Materi Mikro microorganism interactions and microbial ecology

ren(e of

ci:sease.

"

Microorganisms

alsc

interact

by

the

use

of

chemical signal

I

icroorganism

Inte!'actions and

Microbial

Ecology

Concepts

.

Most

microorganisms

in

complex communities

have not

been grorvn

or

characterized.

This

has

limited our

under-standing

of

microorganism interactions and

their

roles

in

nature and

disease.

Molecular techniques are

providing

a

better

uncierstanding

of

these

uncultured

organisms.

.

The

term

syrnbiosis,

or "together-life,"

can be

used

to

de-scribe

many

of the

interactions between

microorganisms,

and

also

microbial interactions

with

higher

organisms.

in-gtuding

plants and animals. These

interactions

may be

pos-itive or

negative.

.

Microbiai

ecology is

the study

of

microbial

relationships

with

other

organisms

and

also

with

their

nonliving

envi-ronr..er+s.

ihese

relationships, based

on interactive

uses

of

resources, have

effects extending

to

the

global

scale.

.

Symbiotic interactions

includd'

mutualism,

cooperation,

commensalism.

parasitism, predation,

amensalism,

and

competition-

These

interactions

are

important in natural

processes

and

in

the

occurrence

of

dis-ease.

The

interactions

can

vary

de-pending

or

the

envi;'cnment

and

changes

in ihe

interaciing

or-ganisms.

l,'i;:'ccrga',s.ias,

a!

:1e, ir:eral:,

<an

iorm

con-rp!ex

o::i,sir;i

assern-blages

that

incluoe

particularly

bicfilms.

Ti-:ese

forn

cn iiving

and

ineri

surfaces and

ha;e

,'najor impacts

on microbial

survivai and

the

occur-molecules, r.,;hich

-

lov.'

the microbial

popula-tion to

respond

to

increased

population

density. 5uch responses incluce quorum sensing,

which

con-trois

a wicie variety

of

nricroorganism properties.

llicrrr.-rganisnir iir

in!

in c;., ironnrcnt\ $ here

ntost knotln trr-girnisttts cann()t \un i\ e are

imporlant tor understandin,r m:e robial diversitr. Thcrc :lrands of iron-oridizinS Fct'ntplu:nttt $ ere discole red

:rroi

ng at

pH f) in an abandoncd rnine near Ret-lding.

Calitirrnia. This hardv micrrxrrcanisni ..:r: onlv

a plasma nre rrbrane to pr()te.t itsell'tionr the

rigors oi this h:,irsh envinrnme nt.

{

a'@

i Jt''f

L

I

.\

+

Energy, electrons,

and nutrients

must be

available in

a suit-aUte "pfrvsicat

environment

{or

microorganisms

to function'

Microbes

interact'.'.'ith

their

environment

to

obtain

energy

(from light or

chemical

sources),

electrons'

and

nutrients'

r..vhich iJads

to

a p,'ocess called biogeochemical

cyciing

Mi-croorganisms chanqe

the

physical

state and mobility of

many-nutrients

as

ihey

use

them

in

their growth

processes'

,

Microorganisms

a'e

an important part

of

ecosystems' or

sel{-regrJlating

biological

communities

and

their

physical

environments. Mictoorganisms

play an important role

in

succession,orthecredictablechangesthatoccurinecosys.

tems

when

theY are

disturbed'

,

Extreme

environments

restrict

the

range

of

microbial

types

abletosurviveancfunction.Thiscanbeduetophysicalfac-tors such as

temperature,

pH, pressure, or

salinity'

Many

mi-croorganisms

iound in

"extreme"

environments

are

"rp".Ltty

adapteo

not

only

to

survive,

but

to

function

metabolically

under- these

particular conditions'

.

Methods

used

to

sluciy

microbial interactions

and microbial ecology

provide

lnfcrmation

on

environmental

characteris-tics;

riicrobial

biomass, numbers, types,

activity'

and

com-munity structure-

Microscopic, chemical,

enzymatic'

and molecular

techniques

are used in these studies'

.

lt

is

now

possible

to

determine

the

nucleic acid sequences

of

specif ic microcrganisms

or

organelles isolated

from

nat-ural environmer:s

and

tc

study

the

phylogeny

of

uncul-tured

microorEanlsms. Tnis shoulci lead

to

important

new advances in

:re

s',,-:dy

ot

rr'icrobial

ecology'

Et

eniItitt? ls r'i t

n

i; -/irtr , tite cnvirottttre'$ selects'

-il.\V

Beijerinck

Chapter2ShlicroorganismlnteractionsandMicrobialEcology

28.2

the area

of

n.ricrobial ecologv

(Nlicrobial Diversitl

&

E'cologl'

28.1i.

The ternr sl,rnbiosis is usecl

in

its

original brr.iJcst

sen:e.

fr

its an association

of

t\\'o ()r ntore clillerent species

r)i

trrganisl-lls.

,\rlJ\

as susgestecl

br

H.

A.

cleBary

in

1879.

;;

V"

\licroorcanisnls

function as

populations

t)l

11\\i

i.llirlrtgt':'rt

sirnilar organisnts. ancl as

communities.

or ttlixture> trf c1itl'erent

rnicr,--rbial

populations. These tllicrotlrganistrts

hrLr

e

e voir ed

while

interacting rvith the

inorganic

*'orld

and

rvirh higher

trr-ganisrns. and

thel'

Iar-ue11' play beneficial and Yital

rtrle::

disease-causi,tg organisnis are rtnly a minor colllponent

ol

the

rlicrobial

world.

if,licroorganisnts. as thcy inte ract u ith tlther trr{;.lt.tisttts arid

their

enr.ironnlellt. also contribute to the ful-rctit'rnin:

of

ecos)'s-tems.

or

self-regulating

biological cotllutunitics

an'i

their

phl:i-cai enr.ironnrent (pp. 603_.+). Knou'leclge ot- litcse i1i3;1161ipn: is

important

in

understanding

both microbial

cotttribr,iiiolls tt-r tire natural u'orld and nricrobial roles in disease

processi:'

.\

major prtiblet-tl in understandin-rr nricrobial interr'-iit]ns is lhi]t

most microscctpicalll, obserVablc nticrclorganisnls cannrrt be -9ro$'n.

The

,lifl'erences between observable and culturable nicroorsen-isms. $,hich

limit

this field even today. har,e been

notei

tbr at least 70 years. This problem $.as discussed in

I

1931 textbcxrk ort soil

nli-crobiology u.ritten bl.Selman waksrnan, the discor

er:r

of strepto-mYcin. anci advances continue

in

this in-rponant

:Ircl

'-\rg

-rc'( _''i()ri

6.-5). \''lolecular rechniclues and sequence data provitle valuable in-tbmrution on rhc-re uncultured

nlicr!)olganislrlr

Pr.,be: .dn be u>r-d

to bt-rrh identit-r specitrc

t'rlrirnisn>r;$ilqk{

r-ttrr]er'tlnd

phi:i-'rii

relationships het* een nticrohes.

(ttentpt!y'r,r :lrtr*

liiesc uticul-tured

micr.tes

re'rains

r

cL-rltrirl

.ffiln

rnicroL'.iui ecol.Sr

t4

P'c0a-b'vw

1nt

)

{/

n prci

n,it. chaptcri

nitcrt>ors.rnirtns

usuallr

h:* e io-en

.,,,r.,,,.rcJ

3.

i:oiriiirl

crltirier. Thc basic ch-'irailcri\tics

Jl.i.rn.,rg"tii.;tl-.

inciuiiiilg

lh:

structurt' enii l'unctiitn

of

micro-bial

cell>.

rltcl:ti.,rli:i-,.

Sr,-,rilh

anil

the a()ntr()l

ol

grorrth'

have been

discti::cd. ln iridrtion.

nlL'labolisnl' gcnetics' and molecular aspects

ol

micrilorganisms.

inciuding

genoniics' har.e been

de-scribeci.Intiiirch;.ipier.riliertlbiliiintcr'ictiotl.rrithbilththephl,s.

ical environtlle nl itnd g

ilil

t'r.her t'rrgatristtl: rr

ili

be contidcred'

Fzar

FoUNDATIoNS

oF MlcRoBlAL EcoLoGY

\,

Tuo

major therllc>

riill

be developed

in

this chapter: (1) the na-ture of microbial relationship: u ith other

living

organisrns' or the nature

of

sl.mbioses. and

tl

r tl-ic intc'ractitlns ot-

tile.e

organisms

rriih

each other and $ ith their nonliYing phy'sical environment' or

I=ZeZ

MICROBIAL

INTERACTIONS

\,'ry

Ir{icroorganislns can

b,--

phl'sicallr

ass0ciatt:ti

ri:ih

oiher

'-rr-ganisrns

in

a

varietr oi

r"ltr.s. One

org]ni:rll

cirtl

n-- lrr''11!-d t'n ttre

:urfacc rrl-lnotltcr.

ls

rin ectosl

nrhiont'

i1i

illi'

;l.:'c''

!h'

'J-tosl'mbiont usuailr

is a snlalier organism located on the surtace

of

a

larger orsanisnt.

ofren.

clissinrilar

tlrranisn'.\ (rl'sirnilar

size are

in phlsical

c()lllllcl.

The

rerrl consortium

can br- u>cd

to

describc'

this phrsical relationship. Consortia

ir

aqurttic

cn-vironments

are

frequentll

complex. involrin-u

nluit'iplc

lircrs

of

similar-looking

rnicroorganisms

that oiten

haie

conlple-mentar)'ph1

siological

properties.

In

contrast'

Lrr'

(r-!lLnL\nl can be located

rrithin

another

organisnl

as an

endosl'mbiont'

There also are rllanv

cases

in uhich

microorgenitms

lire

on both the inside and rhe outside

of

another or-eanism- a

phert\rrll-enon

calleti

ecto/endos)'mbiosis.

Irlteresting erarnple: of

ecto/endosvlrlbioscs i ncl Lrcle it T h i rtt h r i-r specics'

;

:ulfur-''r'

i n g

bacteriurn.

$

hich

is

ettached

to

the surface

oi

ri

navtlr

lar!a

and

u'hich

itscll'corttairls

a parasitic

biicterium'

Fungi

as''"i-ated

u,ith plant roots

(nrvcorrhiz-al

fungi) often contain

en-dosl

mbiotic

bacteria. as ri,e11 as havinc bacteria 1ir ing on

their

surfaces (see PP. 6-t-t--t6).

These

phlsical

associations can be

interrnittent

and

c"clic

or permanent. E,xarnples of

intermittent

and

c}'clic

associatitlns

28.3

Microbial

lnteractio.i

579

r$

v

\rersus

Environment

The ternr "microbial ecology"' is

nor

used in a gcncral *'av to describe

the presence and contributions of microorglLnirnls. through their actil'-ities, to the places uhere they'are l'ound. Studtnts of microbiologl' should be a\\'are that mr-rch of the intbrnration

rx

microbial presence and contributions to soils. \\'aters. anrl associittions *'ith plants. non

de-scribed

bl

this term. u.ould havc bL'L'n con\iLiL-red as "enr ironment:rl

nricrobiologl" in the past. Thornas D. Brock. rhe discorerer of Tlu:r'

ntus utluaticus, rvhich is kno*n the ri'orld

o\-r

as the source

of

IarT

pr:rl1'nrerase for the poll merasc chain reaction r PCR). hl.s civell a de

t'-inition oimicrobial ecologl'that n3\'be useiui: "\licrobial ecologf is

the studl' of the behavior and actir itics of nricr.rorganisms in their nat-ural environments." The important operator in this sentence is r/reir

en-vironment instead of

lle

environnrent. To emphesize this poinr. Bro:k

ha.s noted that "microbes are small: their environments also are small." In these small environments or "micr<xnvironments." other kinds of microorganisms (and macrcx.rrganisms) oftr'n also are present- a critical point that w'as emphasized by' Sergei Winogradsky in

19'r.

Environmental microbiolo-u1'. in comparison. reletes prir:i:iriIr t,r

all-over micrc.bial pr(rcesses that occur in a soi[. \\ i"]ter. or tbt.d. us er-amples.

It

is not concerned u'ith the ptnicular "microenr ir..nrnertt" *,here the microorganisms actually' are tunctioning. but s i15 15.'

broader-scale effects

of

microbial presence and activities. Onc cair

studl these microbialll" mediated prL)cesses and their possiblr' globai impacts at the scale of "environmental microbiologl " n ithout ktxrrr

-in-s about the specihc microenvironment (and the or.-si.rnisnr.

t'Lrnu-tionin,q there) s-here these pr@esses actually' trke place. Ilorr cr er. it is critical to be aware that microbes function in their localizeJ cnr

i-ronments and affect ecos),stems at greater scales. including cuusing

global-level effects. In the last decades the term "microbial

-.ol()S)"

\

largely has lost its original meaning, and recentll the statenrent h:rr

been made that -microbial ecology has become a 'catch-all' teiin." -{s

you read various textbooks and scientilic papers, possible ditlerences bet$'een "microbial ecology" and "environmental microhirrlogr'" should be kepr in mind.

in table

-Z[1.],

Irnportilnl

htltt)lin !ii\L-li\L's. 1:i.,!1olnS

listeriosis.

rnalaria. leptospirosis.

legioncllo:i:.

atrd \

itinosi:

alsrr

inr

oir c

such

intcrrnitlent

and c)

clic

s)

mbiosl\.

ThL-i. tliscrt:c':

ri

ill

ht

discussed

in

chaptcrs

-19 and J(-).

Intertsi:;tg perrllan.nl

relr-tionships also occur betrveen ba.-teria

lnd

riiliitttlis. a:

shori n in

table 28.2.

Hosts

incluclc

sqLrirl. leechcs.

aphids.

ncnlaitrdi-s. enrj moilu-.ks.

In

each

of

thcsc'clr:as. un ir:rirortant

Cl-rri-aJlr'rt.-tic of

thc

hos{

llnintli

i\

conierred bv the n.'rttlancnt

h:1--t.riai

svmhionl.

1

Alth0ugh

it

is

pt,..ihi.' li)

()i\cr\a

Illt-a\!\)r!.tr::.1:..

::l

lit-'t

varicrJ

pirl:iiel

ass,,.i-rii,rti.

',r i'.h

i'iilcl

L':--..lli:lli\.

lilL-

l::-l

iii.ri

therL'is \(rmc tYpe 01'phrsical coniact pror

ii;.

tltr

ir:it'rltt:Ii'.rtl

t'n thc _{lr 1ri'. ()i'}

inl.racli,)it.

til:rt

rrliSi:l l.c

t,:ii:-inS.

T1':c':

iililrr,i-tirtnr

incllde

ntutuali\nt.

;trqrpgr'.r'.ir\n. !L)rttitr-'nsalisnr.

!-rciltitrn.

parasitirnr. un)enslllr\rn. ilnd

.orrlcc't;tiott

,

tigure

2!i.l:.

In

llrisc

p3n.

thJ\

\\ L'rc f-ir\t tic:e ribetl ilitd rle f ined 'c;' bioit,rgist:

:turil

ing

Srmtrimis

H6t

Cvclical Svmbionr

Plant-bacterial

l\{arine animak

Gurncra (tropical

angiosperm)

Azollalrict, paddy fern)

Pruseo{us (bean)

Adisia (angiosperm)

Cmal ccle*tcrares

I-uminots fish

Squid

.\'os;,,c i Cr anobaaia:;un )

Anubatnu 1r\ 3lr\r-.. lrriunl !

Rlii:.rtitiu.nt i \. llrg: .

Prtfi tb.tL lt t iiqt:

Sltnhiro!:tiut:

{ dinillmari ir'rtl ,

llhrio- P ltoit,i,,r. :. ., _:,'r

Phrtnit:;:t ri:t,r: ;: ':, ,t

AdaFed 116 L $*frrtis std lf- J. at lrua 1998. Erd*;.,mbios: Ct.llal anJ rtr.rt.r in c\

\Eri@-Treadsin,rit al,i,t og; Atf32--46,t bles I,Zaei3.

Examples

of

Permanent Bacterial-Animal Symbioses and

the

Characteristics

Contributed by

the

Bacterium

to the

Symbiosis

Animal

Host

Svmbionl

S!'mbionl Contribution

lntermittent

and

Cyclical

Symbioses

of

Microorqanisms

with

Plants and Marine Animals

Sepiolid squid iErpnrrrrrtt scolttltts\

l\'ledicinal leech I H i rudo med ic i na I i s\

Aphid (Sclu:nplt i s _I rlil i tl um )

Nemattxle *orm (lteterurltabditis spp. t

Ship*'onn mollusk (Llrorhs pedlt ellatus i

Luminous bacteriu'

Enteric bacteriu m ( A e mn n tuts re ronii)

Bacterium t B uchne ra aph id i colal

Luminous bacterium ( _I

'.otorhabdus luntinescens)

Gill cell bacterium

Luminescence (\/i b rirL

-fi.t I t t' ri :

Blood digestion

Amino acid synthesis

Predation and antibiotic s1 ntheris

Cellulose digestion and nitrogen fixation

lnteraction

type

lnteraction example

Mutualism

Cooperation

Commensalism

Predation Predator

J\e

->

Parasitism

Amensalism

Comp€t,tion

One outc$mpetes the

other for the site's resources

^

a

!.-____--__

A.-}4E

\J

-Both coexist at i"c:yer leveis. cue to

their sharing the limiting resource

Figure28.1

llicrobial Interactions.

Basicchareitclr.ii.:.,i

sr nrbiotic inic-ractions that can tx'cur betr'* een diftcr.-nt ()r!r1i'ri.nt\.

piants. aninrals. and

easilr

ob:cn

ahlc

nicrobill

:r:scnri-l:,ri..

H.

A. deBarl's

uork

u

ith

lichens is an er--ellcnt e rrirttplc.

'I

.

_Define

the

_{terms symbiosis and microbial ecoiogy. Ho,,'., are}

they similar and different?

2.

Define the terms population, communit\,, and ecosystem. -1. ln what ways can different microorganisrns be in phr,sical contact?

4.

List several important diseases

that

involve cyclic and inter-mittent symbioses.

saG

Chapter

28

Microorganism lnteractions and Microbial

Ecology zo4

/---7

prey

(__S**

\Iutualisnr ILatin

rrrrrrrrrr.r. lrorrnuc'cl

or

reciprocal

Idefinc'r tit:

rci.,iirrr)ship

in

u

hich

5ir111g pggiprl-i'rcal bcnr'f

it

lc(-ru.':

to

b.'::r

Iriiriilirs.

J-hir

i.

an ohliSatrrtv relatitrnslrip

in

rvhich thc

nrutual-ist rrnri tirc

ho.t

are nlctuh()licalll'clepcndent on c-ach othcr.

\\'hr':t

\c|.rratLrd.

in

nrenr

cascs. the rndit idual organisnrs \\

ill

not

\u:-vir e. Sevcral e\anrplr's

of

rnutLlalisrlr are presented next.

Microorganism-lnsect Mutualisms

\lLrrullistic

r-issi)ciuti()rls are conrmon in the insects. This is

rclat:;

to

thl

iirods used

bt

insects. rvhich oticrr includc _{Irlunt siip} or

ar',i-nlil

llirids

lrckinq

in

esscntial vitanrins and anrino acids.

l'hc

i-.,-rlulr'.J

\

itartiin:

:.rnd

anritto acids

lire

provitl.-d

hr

bactcri;r

\-\ nlirronts in erchange

lirr

a secure phi'sical habitat and anrple nl.,

rricir!..

The aphid is an c'rce Ilent exanrplc

oi'this

nrutualistic

r.'lr,-tirrnrhip.

This

insect

cclntains [Juclurcru

rtpitilicttlu

in

il.

irtopiasrn.

anJ a rnature insc-ct contains

literalll

nrillions of

the':

brrit.'ria

in

its kxJl'.

The Buclttrcra provides

its

host

uith

anrin.r ricids.

particularll

tryptophan. and

if

the insect is treated rvith an-tibicrtics.

it

dies. I1/o/1-rrrt'ltiu _ltipietttis. a rickettsia. is a cvtoplasn',i; cndrrsvmbiont tbund

in

15 to 209t of insect species and can Cofltr-trl

tii.- r:prtiducLi(rn

of

its host. J'his microbial association is thouSr: t() i1a

il

nra.ior tactor

in

the el'olr-rtion

of

r

-'r

:r.r.l s, e - ia.,or.

ir.

.1.-i-irl::iii!

rr usp:. II?r/lrzrr'1rirr ul:o cun c:.lusc cvtoplx\nric ine

(,ntptr::-rililr

in irt:r';i:.

parthcn()SL'nesis

in

butterllies. antl the

lcnriniz.-t.i,r.

,,i

SCn.iii

nrales

in

i\()p()ds.

\\'hat

could bc Ihr- adrantasc ti,

,.i-':

\il,lltti'ltitr

'

Br

limiting

_sexual

virrirbilitt'.

_thc

blcteriunt

_rliS'i::

i-'rnclli

br

e rc.iting a nt()rc stablc a\L'xLlal enr ironnrent

tbr

it\

o\\ il

i,,n iL-

j'-lcrril

li:;irrtcnancc-.

Our

undL'r:trnding

of

rricrobe-i nsc.-t

:ruiLi-rli\nrs.

il;luding

thc'role ol'lIi;lDirr'lirir

in

irt.ects.

ir;,.;-,-.lrrir'il\

.\Funiir:l

u ith

lht

incrca:c'd u\c of molL'cLtlar techniuuc:. -l-irc

1-1'.,11,;,111n-terrtritc

rclationship

ir

a

clus'ic

e

xantirlc

,,:

.'

.:::r,,li.lr

ir: ri hich

tlrt

ll:r:.:lllitcLl

pr-(-rtrr./()ir lir e

ir

iirc .-gul lJi

t.:

;..;t:.

::n.i

rrr'.,.i

ro::cltc:

tfigure

28.h\.

Thesc

lltscilutcs

criri

i,:,

.

.ii'-t t.i'c:iri'.'h,rdralc\.

iicquircd

us

criluloic

inucrt.-d

h'.

thcl:

t:

,-:

ll_lLtri 1..11:).

I

lt.

lr()tr)loi.r

cnrLrlt

rioirtj

nuriiclr-s.

tiirc.:

i:ri .rllui,i.c.

urd

nrct.ihtrlize it to acctalr'anrl other

L)rodu.t\.-fa:-r':rr,-:'

r.ridizr

llic

uccta!c rclca.ed b_i thcir

lluscllutc'.

BcclLuse

ti::

ir,,.t

I'

lilnro.l

al*'ar

s incapable

of

:r

nthesizing cellulasr's

(cl

/\ nri\

thul

cr:lLIVsc th.-

hrJrolrsis

ol'c.-llulose).

it

is depentie

r:

\,:1

i-ili

nr.rtui.rii-tic prot0zoa

lirr

its existcncL'.

T:rjr

nrutLi:,li.tie

rclation:hip

can be readil_r'tcst!,d in the

llt,-i);;ri{)r-\ i1'*tr,'.1 roacher arc placc'tl in a

bcll.jar contarnin! \\(),,*

riri1..

1,r',.i a

hrth

conccntrati()n

cll'O..

Bccausc-

O.

is

to\ic

t()

iitj

ll:i.:.'llatcs. thr'_r tlic. Thc

sood

r()ucitcs arc unallcctc'd b1 thc hig:.

().

e.,ltecltlratr,'li;.rrtr-l u()t)tinue to in_cest r|ortd. Lrut

thc\

soon

iiic

()1

\tiir\

ation duc to a Iack of celltrlases.

Zooxanthellae

\l:Lnr

ntrrine

inrertebrates

(sponges.

jclll'tish.

sea anenrone:.

e

orril..

ciliatc': r harhor endost'ntbic'rtic. sphcrical algal ceils call.-.i zoo.ranthellae

*

ithin

their tissue

(figure

28.3a t. Bccause the dc-gree

rrf

host dependencv

on

the

rnutualistic

alga

is

sonte*hai

r ltri:thlc.

trnlr

one ,'r'ell-knog _{n exantple is presentcd.}

Parasite

@ --->

-+

.,,^:.

--- 8

,

\_,'

/:

\o

8,,

-t

2 8.5 M

icrobial lnteractions

Figure

28.2

N{utualism.

Light n.ricro-graphs

of

(a) a

s'orker termite

of

the senus Relicrr litenrtes eating $'ood ( X

l0).

and

(b)

Trit'hotttmplta.

a multillagell::tr.d protozoan

tiom

the termite's gut

(x

I-l-i). Notice the rnany

flagella

that occur

trrer

nrost

of

its

length. The

abiliq ol

Trit-ittt-tttrrtphu

to

break do,'r,n cellulo5g iillorvs ternrites to use wood as a fbod source.

{a) (b)

Figure

28.3

Zor-rxanthrllae.

(a ) Ztxrranthellae igrc-en t u

ithin

rhe

tip of

a hvdra

tt:ieclc

i

.;

1-i())

(b)

The green

color

of

this rore etrral ,

1/ruiiliirlt

i.

due to the abundant z,ooxanthL'llae

*ithin

its tissues.

'l

i:r

it,:r';:trrtrpl-

rl.s1l-[llildinei

_cirrals

(ligurc -S.i/ri :liii'i-'

iri{r\i

(,:

tht:r

cne

r:,r

rctluircrttents usins thcir l()()\l.inthal1.ic.

P;i

iIcnl.

ar(\i,.i-,:.i

irr thl

u()rrrl pr()tcct thc algae

frtltrt

thc

hltrtl,iul

c11c.i.

ii1- r-rll:-lrr

ilict rridiltion. Clearlr

Ihe

zor,rlrtiitcllae

:rl.rr 1...'r::ll llrt' .,'r-itl

tr':,.iu.e

the calcille uli()n r:.ltc is lrt l.-ust

l0 til:l::

!r..rlui

irr

tl.ir irgirl

ihrrrr

irt thc

dtrk.

Hcrntatrpic

c!rrrrls

lx.l.inr

/!)(\\ilillire

ll.ri

hlir.'l

r crr.

los

rate o1'calcitlcatiolt. B:r:ctl ttn lhrr'it'

\ilirl.

aurb(,n j*1rlrrpic crrrnposition.

it

has heen dcterrninr'd Iirat nr\)\l (,1 the

i,rllini.'curhon

in

thr'tissue:

of the

hcrntatvpi!

e()rel\

llrs

uornc 1'roir thc ziroranthellae. Becnusc of this corel-algal nru-tLrlrli.tie

rclriti,rrrr[iip-c:r|lpt;jpo.

crrrtra-11 jp-o.

lnd crc]inq

nuirt-inlr

urrJ

cncr:-)

!(ri-al rcL'1s are iinl()nS the nlost prrrdLrctir.e lnci \uauc..tLll

ot'kn0$

n ec()s\ stems.

Sulfide-Based Mutualisms

Tube u'orm-bacterial relationships exist several thousand meters below the surface

of

the ocean, where the Earth's crustal plares are spreadin-e apan (,figure 28.4;. Vent

fluids

are anoxic, contain high concentratilrns of h; Jrogen sulfide, and can reach a temper-ature of _-3,50'C. The sea\\'ater surrounding these vents has sulfide concentrations around 2-5C

pM

and temperatures

l0

to

20'C

above the normal seawater temperature

of

2.1"C.

\

5$2

Chapter

28

Microorganism lnteractions and Microbial

Ecology

Figure

28.4

Rasic

Structure of

a

Hl.drothermal

inciLlJinq :ult'i.-it

tra

rL'i.il\eJ

lls \e3\\'ater penetrates crL'aIing L'uvir()nrlteni\ tirr _-crtlu.th

of

the tube lvorrns

Ir,

.i:rrt

eli ltlcmpt. io

cltlture

these isolated

bacteria-likc

or-gllil,:.ir:

i.ilii c

i.':ctl tln\llaaa\\iill.

J'l::

tLrl.l ,.i(rnri

i.ii.\

up

itrtlrogen:ultltlc

irtrtrl thc \ca\\lltLrr anrl i-.iild\ it 1rr

h;litlrlrrhiri

ttilc

rea:Lrn the

$orll'ls

are bright

rcdi

'l-hc

hldror:cn

'ultide

i.

thcn transPoned

in

thi:

lirrm

to thc

bac-tc'ri-.

rlhici-r r.r\c

tlrc

\Lllfide-reducing pou'er

to

llr

carbon

diox-itl.'ir

thc

Celrirt r.

cli

(.,t'r'

ligttrt'

1{t.1).

The

COl

required

lirr

thi: ire

lr

is t1'r1r1>p(rried t,) the bacteria

in

three $'a1's:

freell

dis-solretl

in thc t lot-,ti. bound to hen-rogiobin. and in the

tirnn

ot'or-garic

aci.ls \ttch

1:

tttalale

and \uccinate. Thes.'acids

arc dL:ciri-h()\\'liiie il t() rclcuse CO. in the trophosome. the tissue

crln-tainin!

Iracicrtal

\\ Il,r':i)itl\.

Using the:e mechanisnls. the

bactc-ria

l\

ntir.\ilc

lcr.iuccti ()rganic

nlaterial

fronl

inorganic

sub\ttnce\. Thc o|cani-

ntaterial

is

then supplied

to

the

tLlbc

\\'()rnr

lhroush

its

circulatorv

svstem and sen'es as the main

nu-tritional

soLtrcc

for

the tissL'

'

cells.

A

.inriIur

nrutualistic relationship occurs in Ridge iu pisc'c.tttt'.

I

tuh,c

*ornr

lound in the north.astern Pacitlc. This aninlal

rnain-rain:

its

cndosr

nrbiotic sull'ur-oxidizing

bacteria

in

specializccl

tissue

:.

sinrilar to the nutritional strategv of Riliirr.

\-ent

u'ith

its

\Iutualistic

)licrobr-.{ninral Associations.

Reduced chetnicals the fracturetl

hlsaltic,)ccr,l

li,,,,.-

:'

itr'lrtct1. irttti returns

r\

\'ant

lluiil

to thc- txt-an. and their procarr

otic

lnulr,rali.t..

Methane-Based Mutualisms

Other unique

tr,>rd chains

inrolr'e

rnethane-fixins

nricroorgan-isnts as the

llr.t

rtci) in

pror iding

orglnic

nlatter tor consuflrers. i\{ethanotrophs- bacteria capuble

of

using rlrethanL-. rru-cur as in-tracellul:rr sr nraionts

of

methanr'-r'ent mussels. In these rnussels the

thick fleshr gills

are

tllled

ri'ith bacteria. ln addition. methan-crtrophic carnivtrrous sponces have been discovered in a mud

vol-cano

at

a depth ,ri' -1.9-1-1

nr

in

the Barbados Trench. Abundant methanotrophic

.r

mbionts u ere contlrmcd

br

the presence of en-zymes

related

lo

nr-thane

oxidation

in

sponse tissues. These sponges are not

ratisllcd

to

use bacteria

to

suppon themselves: thel' also trap sr,."iinrnin-s

prc\

to give r

urietr

to their diet.

1.

V/hat is the

l'lical

characieristic of a mutualistic relationship?

2.

What are

irir'lrtant

rcles of bacteria, such as Buchnera and Wolbachia in insects?

3.

How do tube .', crms obtain energy and organic compounds for

their growth?

4.

What is the s:urce of the rvaters released in a deep hydrother-mal vent, anci how is

it

heated?

28.6

hydroxides and iron silicates f.om

rising vent fluid precipitate in seawater

forming white and black "smoke.'

precipitate inside vent and chimney

Seawater seeps through

6.t

he Rumen

Ecosystem

Luminants urc

r

gri.',i!r,,i^l:ri-b:ro1 ,r1.1.;1,;jv-r11il. ihril

i:lre

a

\t{rlll-:h

dir iderl int0

iirit:

a\)nriiliiirite

ili\

:1il!i

.llc\\

u e ud crrnsisting

tli

:gurgitated.

partialrr

digc-t.-ri li.lo.i. Eranrplr-. include

cattle.

ier,

alk.

calll!'l\.

bur'iilr'-:1lJCi'.

-!r':rt'':rnrl r:lliic:

The pllrnt

ialcrill: u.td

as

thcir

rtllritt iqrqrli:qr11;-3

il.ili!ill'

.rlc

(tl

_P.)or

nLl--itionll

qu;litr

_:

lar:;

_i

olturt';.

(\l-lllri-r-lil\

_{ttlLi.l l-c rttscsteti ilnd} r'(\]c\:ed in thc gLrt.

ir

co0lrll:.riii,r':

i,';llt

e olttf

l.:r

ttritrrlhiltl

eonl-runities. I{r nrect the nirtritii,rr:ii ncc.1. ir1'lhe

lt:inllrl..'\r

liotrld

hi

\p.ctrrl. thr'Sttt in lhc.c.,tll:il:rl' i:

LlrlitlLrtlr :rilllJrlgll l'rrr p;o---:sirtg plant lllatr-fi:r1..

Br

Lr.:rll

11,i.i,,ir191i11l.itl: tt, cielrlidc lhe rick ccllu]rrrc r,r, _alls

ot

!fli\-

.:ild ()lhai \ t'!cl:.lti{)ll, fLlnlinanl\

di-r\l

\

ir\t

ililt!)Llnls

of

itthcru

i\d

urtli\

lillrhlc

ti)i-ugL'. Ilcultusc

nt-)in!nts

cannot

s\nthe\irc ccllulu'cs. ihet hlrc

c:tablisitcd

a

rutualistjc

relntionrhip

\\

ilh

rnacr()bic nricroorsertislrts that pro-uce

thes.

L-nr)'nrc\.

Cellulrrc. Itrclrllrzc

the _[3t

l+Jt

lirrkages Jt\\'r-cn

\uaccssi\e Ir-!lLtco:,;

rt:idrte.

ol'

ccllulrlsc

lnd

rclcasc lr:cos.-. r" hich is the n tcrntc'nl.'tl to ttrulrnic

acitl:

sttclt lr\ aceliile.

Microbia I

lnteractions

543

Gill plume Girl

plume o2 CO, H,S

o2

Co.

H,S

HSHbC-Transloc:'ion products

Sulfide

oxidation

Calvin

cycle

Vestimentum

Circulatory sys'iem

Coelom Trophosome cell

Bacteria Capillary Capillary

Nutrients

Endosymbiotic bacteria Opisthosome

igure

28.5

The

Tuht

\\ornt-lJacttrial

Relationship.

(a)

A comnrunitl of

tubc \\'()rrns

(Ri.liiti

_{1t.it'ltt1)tilot ,\t the} Galirpart-r:

Rift

vdrothcmral

rent.iic

rrlepql

l.-i-ilt

r:r.,. F-lch

\\orrn

i\

more than a nleter

in

length and has a a0 cnt

siil

plume. 1b.

c)Sclrernatic

ilirrs-menturn..{t its

itni.ii():

r:tLl

is ri ii.;riritt():-\

r:il1

plunre. Insidc

thc trunk

r-rf

the

uornr

is

a

trophosonre ccrr)sistin!:

primlrily

of

ndosvntbirrtic

bacrtria.

lrs:r,gilitcd .e

llr.

aird L,ltrrd rersels.

At

the p()sterior end

of

the animal is thc opisthi)sonte.

\\hi.h

ancht)rs the

lrbon

c\lrrpoLlnd.

.);ithr\i.,;'!j Lr ,ir.

.;l1iirrr rir)i(rn1

i\

trllnsl(rrrled

to thc aninlal'S tissues.

o2

co.

Hr"

(d) (c)

(b)

hutr rate. and pro;ritrnatc

{.\('('./i(i/r(

9. /r/r. -I'ticsL'():glLnic

rJii:

iiri

thc' trur' enL-rg\ s()urcc'

fitr

thc

runtiitilnt.

Organic

Ir:ltler

[]i!)ac\\-ing can cither

stop

at

the

aictlle

lc-r

el

()r

continLle

ttr

forrn

lnethane as a major end product. These

trio

pattL'rn\

of

process-inr

rppear lt,r he undcr genctiL'

iind

ph\ loScnetic cLrntroi as dis-cussed in

\Iicrobial

f)irersitl

&

Ficologl 2t1.2.

The uppc'r porti()n of a

rurlinlnt'\

stonrJch crpuncls to

lornr

a

laruc'pouch

called

tire

rumen

({igure

2lJ.6l anrl al:ro

r,t.nraller

honelcornb-likc

rcticulr-rnr.

The

bottonr

portion

,r1' the si.rnrach consists

of

an antcchnrnhcr call3(l tha ornusurn. r,.

lth

thc

"trr-re"

stonrach (abonrr:urn) behind it.

The

insolublc polvsacchliridcr

and

ccllulosc

caten

b\

the rurninant are

nrircd

q

ith

saliva and enter the rllmen.

\\'ithin

the rumen.

lood

is churned

in

a constant

rotiirv nrriiit.rn;lni

eren-tuallv

reduced to a

pulpy'mas\.

\\'hich is

partialll

diqested and f'ernrcntcd

bl

lnicroorganisrns.

Later the

1'ood nroves

inio

the

reticulunr.

It

is

thc'n

rcgu|uitated

as

a "cud." $'hich

i:

thor-ouchl\

cherr'ed

forthe

tlrst

tirrc-. Thc t'ood is nrixecl

riith

saliva.

584

Chapter

28

Microorganism lnteractions and Microbial

Ecology

Organisms with digestive tracts had to make an interesting el'olution-ary choice: rvill the microbial conimunitl' procluce methane or not? The use of plant materials as a major firod sourcc does not alrval s iead

to methane production in the di-gestiYe tract. For exaniple. kan-qrrt'ns

do not produce methane. u'hereas sireep and cattle do. The kangaroo

has a distinct advantage in terms of nutrition. \\'hen complex plant nla-terials are degradetl only to organic acids such as acetate' the aninl:rl's digestive system can <lirectl;'absorb thc acids. In sheep and cattl--' the

microbial communitl is more complex and conr erts acetate-ler''-i

:ub-strates tLr methane and carbon dioride. Ieading to nutrient los: 1-'om

the original plant material. This loss can be substantial. u ith l 0 to I 59i

of the r.-rganic matter in the feed lost to the atntc'sphere as meth:rne'

An

eramination

of

over

2'i0

reptiles. birds. and maninals

shou,ed that their nraintenance of methanogenic nlicrftrr,eanisms and

methane production

is

under phvlogenetic and not dietary control

(see Box figure). Although low levels of methanogens can b.'

de-tected

in

venebrates that do not produce much

of

this imp()rtant

greenhouse gas, the lack of methane production seenls to result troul

absence

of

methanogen receptor sites

in

the digestive svst!'nl. As shou'n in this figure, the ability to maintain methanogens otten has

been lost. A similar situation occurs s ith a(hropods: nltthane is

pr()-duced by only a t'erv organisms, including tropical millipedes. ctrck-roaches. termites, and scarab beetles. If the presence of nrethanoqens

results

in

u'aste

of

nutrients, '*'hv have so many venebrates and

anhropods maintained rhis "energerically rvasteful" process.) It is an

interesting question that relates back to the basic nature of venebrate-gut microbial communiry evolution.

Cervidae

26.6

Dan uacaca- /

v

papio

Cercopitnecinue

/

\1

Galagonidae

! I t

1

i

fdtoae - r

I I

r,

'.. ,'

TalPa

Tenrecidae

_----_._,

r.

Caprinae Bovidae

Tragelaphinae Choreopsis

Equidae

Tapiridae

Rhinocerotidae Loridae

Suidae

Tupaia

ChiroqteG Tayassuidae

\

Dolphinapterus

----g--

rurs,aps

Trichechus

OrycteroPus LoxoConta

Choleopus

Elephas Dasypodinae

Procayia

Myrmacophagidae

\Iicrobial

Dirersit-v-

and Ecolog1.

Cloerolurion

of

animals

and their gut microbial

communities:

the

methane choicc. lUethane-producing \.ertcbrate s are noted rvirh

solitl

recl iines and roman letters; nonmethane producers are noted

u'ith

blue dot-ted lines and italics.

r.\\\

rllo+

r'd. and reclltcr\ tite rtttncll rr hile atlothcr cud

i:

pas'*J u1l

ro the mouth. As

thi:

pr()ccss colltillLlcs. thc pirrrialh di"csted trlant rnarerial becorrtes ntore liqtrid

in

nllture. The

liquid

ihcn

begrr:

ttr

t']ou,out

of

the reticulLrnt und into the

louer

pli.rts

oithc

ston,uch:

irst

the onrll\urn and then the atrotttasunr. ]t is in the abtlnlasur:', that the

ltxxl

encounters the host's nortrlltl digestirc

ellz\nlei

and

th:

di-gestive pr(Eess continues in thc regular manlmaliltn rr ar.

The rumen clt'methane-producin! anintitls such as eattlc criil tains a large and diverse microbial

ctlnrnlunitl'(about

l(lir,'t!.tit

i"n:

per

milliliter).

including

procarvotcs. anaerobic ir.tn!'i

:tr.ir

as ,\'eocullim.lsll.r. ciliates.

iind

other protozoans. Ftxrd

entcrirlr

the

,lnren

is

quicklt'altacked

br

the

celiulolvtic

aneerohic prt''

carlotes. fungi.

and protozoa.

Although

the nlasscs

ol

procarr otes and protozoa

are apprtlrinlatelv equal. the

prt,ues:it.t': , rl

Homo

Gorilla

Giraffidae

Camelus

28 -o

Omasum

lmall intestine

AbomasLm

(true stcrach) Reticulum

Figure

28.6

Ruminant

Stomach.

The

stotnach c()rlrplrt-ments

of

a co*'- The microorganisms are active

mainlv

in the

rLr-rnen.

Arrou

s indicate direction

of

food molen')ent.

runren contents

is

carried

out mainll'

bl

the procarrotc:.

\li-croorganisms break

do$n

the plant material. Bc'ceuie thc

ritiue-tion

potcntial

in

the

rumen

is - 30

nr\-.

ail

indigc;r',1r. n:icrtrrrrqanismi engage

in

anaerobic

mL'ubolisnl. Thc

hlrctcl'irr

It'ilncnt

carbtlhrilrates to tatt-r' acids. carbirn

clioxi.ll.

al.tti

il,r.:r,'-!rn.

The

archaea {nrethano-eens} produce methane

tC}l-rir"r:l

ru.atiltL'. CO1. and H1.

Dic'tarl' carbrrh)'drates degraded

in

thl-

nlnlen

include :,'l'-ri'l'-:

\Lllilrs.

starch. _FEctin. hemicellulose. and cellulose.

Thi

ilLi-gc'l lL-rccntase

of

each carboh)'drate

is

fermented

to rollilil':

i.:l1r

ruids

(acetic.

propionic. butyric. formic.

and

valcric;.

C()r.

i{--rn,J m.-thane- Fanl'acids producc-d b1'the rumen trrsanisltt: rir.

:!b-.rlrbcd into the bloodstream and are oxidized

bl

the

anilrrrl

:r' ilr

nrain source of energ)'. The

COl

and methanc.

produicti

lli

l

l".rte

oi ltXl

to -100

liters

per

daf in

a

co*',

are rcleaseri

hr

_{'-rttcl:,l:ott} I,l-lrtin

enrt'turc.

to

ht'lch].

a continuous.

scarcell eudihlc

icl;cr

prL)ce\\ sinrilar to roLlching. ATP produced during

tcrnlclllirl;,'rl

r\ u\rLl to \upport the grou'th

of

rumen

nlicrt,organitttt'.

-l-ht>.:

llli-cr()organisms

in

turn proiJuce nlost

of

the I

itlnlins

nc'!'d.(l

b\

ih.

runlinant'

In

the renlaining

tuo

stomachs'

the

nlicr' r( )iq'rrrl\rlr\'

h:.ir

in.

performe.J thcir s1 ntbiotic lask. are digr-stcd to r

itltl

r,::lIil"

acids. sugars, and other nutrients

tirr

ruminanl use.

Cooperation

Cooperation and cotrlnlensalisln are

t$o f\)5iti\c

btti

lltrt

ol'll:rr

tor\

I\

pes

of

sr ntbioscs

tirund

ri

idc-lr

in thc nlicrobial

rl, _'; 1i.1.

J'hese involve

slntrophic

relationships. 51

ntrophisnr

IGreci

'rr;. togcther. ant) tntplte. nottrishment] is an

a':ociation

in u llie 1-r thr:

tirr\\.!h

ol

one organism

either depend\

Lin

or is inlplCrc.l

ltr

gro\\'rh

factors. nutrients.

or

substrates pror ided

br

rnothr-r or ganism grou'ing nearh\'. Sometinles both c.rgiinisnls hent'l'it.

As

noted

in

ll.,ure

2E.1.

cooperation

benefits bt'tl.i ttticrLrot

-sanisms. but

this

relationship is not

obligaton.

Beneflcjal

cotrr-tr,iroJen \.----l\ _/

fixer i \

,/ Azotobactei / \

tuvtv@elatt /

\-

ctucosei

N2

Microbial

lnteractions

5a5

coa

H,S

Light

Chromatium Desulfovibria

//+NH4'

/

/

/ \t

/\

tl

\t

l.riroSen \.-r--l\

(b)

Figure

28.7

Iiramplcs

of

Cooperative 51

mbiotic

Processt's.

iarThr'org:rnic

nratler (O\1 ) and sultate required b,v

Dcsul.fovib-r.il

are prrrdu;ed b1 the Cltrtnnatiran

in

its pholost'nthesis-driren

r.riLre tir)n o1'CO. 1o organic mattc-r and

oridation

of sulfide to sui-i;.rl'.:. i tt

I

.-\;1t!rltLtc-t€r uses

glucose

pror

ided

bt

a

e

cllult,.t-.i-:::i:-rrlitt!

ir::i,xrrg;ritisrlr

such

ltt

Ccllulomrtrtri.t. u

hicit

tt\cs lhL'

,,:trorcn

Irrc.i

h1

.\:otoltot

!t'r.

;lcilrcntarr

r.>()urces are

provided

b1

each

of

thc

paired

rIi-!t'{)()rqallislr\

-flrc irrsanirrlls irrr.olYed in

thi\ t\

pe 01're iliti0nship

.en

he scparatcd.

anil

il'thc'

resources pror ided b1 the

corttplc--rlcntan

nici-oorganism are supplied in the

sro$th

enYironnlent.

.ilih

nlie ro(rrSanisrn ,,r'ill 1'unction independentlr. Tu'o cranrplcs

',;

thi:

t_\ pc

()l

rclatiortshrp :rrc the as\(rciation

ol

I)cstrl.fttviltritt

'.\ril

_{C.'ltr()nttilllorr}

{tigure

28.7a t.

in

u hich thc carbon and sult-r.rr

.\

clL-s

arc

iinkcd.

and

the intcraction

oi

a

nitroSctr-tlrin::

rtri-ulrrrrr-irnirlir

"i

itlt

li

e e llLrlrrlr

tic

ttrpanisnl such

ts

C.'tlltrlrtrrtttr:rt';

, r

i!,.rrc

lS.-l,,. ln

thc

sccond exarrtple.

thc

ccllulose -tlcuradinS

iriir..r()ilrqani.nr

lihcrltc:

glucose

fiont

the ccllr-rlrrse. ri hiclt can 'oe

ri\a(l

h\

nitrrrrcn-t'iring

tnicrobes.

.-\n

crccIlcnt

crlinr!lc

of acoopcratire biodegraclatirc

associ-ririon

ir

slro,.i

n in

{igure 2fl.tl.

In

this

case

i-chlort)beilzr)r1-.ilsradatitin

dcpe

nd.

i,rt thc functionin-c

of nticrtlorgani.rlls

rr ith a()nrplL-nrcntlrr caplrhilitic-s.

It'anv

one

ol

thc- three

tnicr,r)r!rtll-i.ntr

i:

11()l present and actiVe. the degradation o1- the subslratc

\\

ill

not ()ce ur.

\":::)

5a6

Chapter

28

Microorganism lnteractions and Microbial

Ecology

Desulfomonile tiediei

3-chlorobenzoate

\\

\*

.,

/

/

MethanosPirillum sP.

Figure

28.8

Associations

in

a Defined Three-IVlembered

Cooperative and Commensalistic Community

That

Can Degrade

3-Chlorobenzoate. If

any member is missing' degra-.iation

$ill

nor take place. The soiid arro[,s denronstrate nutrient

tlo*

s. anci the dashed Iines represent hyp:the

:i

:d

ll^n

'

l

l

otirc r . urpcra!i r c relations. .ul f iclc-drper,.1g11i 3Ll11111 oirh i

-liii.rll.nt()u5

rnie rot,rgunisltls

tlx

carbttn

ditrridc

lltd

sr nthc;iz-c-()i-I11tlie ntal!ai

thtt

:e r\ cs as a carbon and energr s0ttrce

ftlr

ii

ilsi-.r ()'rr()piric organisnt. Solne

of

the ntosl intcrcstillg

inclucle thc pirl'. chrtc'tc \\ ()rlns

.'\lt'inella

pontpejatru

(figure

2tl'9t'

thc

I)orn-peii

irtrnrr.

:.,rrl

ltlr,,

PLtrulvittellu Pttlrtti.lltt'ttti.s, the

Paltll

ut'rrn'

il,,ih

ir ar c tl ;l:l lc tl i, , Ll. bae Icrilt oI) the ir dorsal :r-trl ace-' '

l-hc:e

Il

l-28.1 0

Figure

28.9

A

N{arine

\\brm-Bacterial

Cooperative

Relationship.

Alt'i'telltt

potnpejana, a

l0

cm lon-s worm- forms

a cooperative reiationship u'ith bacteria that grou' as Iong threads on the

\\'orrn's

surface.

The

bacteria and

Alrinellu

are

found

in 'unnels near lhe black s.-roker-heated water

tonts-ilnrent()ri. hecrcria can

ilileralc high lerels

of

rn.-tals such a-s ar senic. cadtttiurrt. uttd copPer. \\'her,

gro*'illg

()n thc surl'ace

ol

thL

aninral.

ther

nlir prorii:

proteclion

lrom

these

toric

nielals. a'

',rcll

lts

thcrnlal

pl'()lL'cti()n: in addition.

ther

appear to be used a'

il

tilod

5()urcc. -'\ dL'eP-\aa crtlstacean

hat

been

discolercd

tha

u:e,s suli'ur-oridizirtg ar-riotropiric bactcria as iis tbod source. Thi .1rrrrill.-.

liirirrtrrrr.r

('.\i)'-itl(tt(t

ttigurt

lll.10r

has

tllamentou

p/

s/

s'i

Sr

I

I

I

s's

,EI

Figure2g.10 AltarineCrustacean-IlacterialCooperatireRelationship.

ra)Apicture,-rf thenlarineshrinlp

Rintir:urisetoculutu

thi.

t1-rirt SCill'ri1.

587

28 11 l'vl icrobia I lnteractions

Figure

28.'1

1 ,\

\Iarinc

\ernutodr-Ilacterial Cooperatire

Relationsliip.

\Lu-ine i.ru..-li:'irr

IiJ;i:r,i,,11;'..

\\hich

:.:rtrrr

at

thc

(b)

(a)

-LrllL:r.-rrritl:,:irl.t

b.,-al;-ii !rr,,r

1;;;

,,;l

ii:

:urlace

(trgure 18.1i)hl.

\\-htir

therc

rrc

t1i-i.,.j-lc,,i

ilrr

.hli

irt:-r ingr--sts them.

This

ntlrni-nuilr

"blilr

j"

.h"ii:rl

!:,1 1-J\ii,

iri

!,,

iir:

_{Slou r'mitted} b1 thc

bllck

\:il(riii'. t-t.:l!

l,

l,li-:J-i:"r

(ri'ii.:il

r,ll ils

hack. ThL'()rgan

i\.1-ll\i-ii..r'to

l

iishi

r'.iirtllltlih

lil.1'!

i:

tt,rl tlct.-cteble bv humans.

.\nolire:

intcrc:i:r:

c\unrllla

oi

brictc'rial epigro\\'th is shor"n br

ncnliiode\.

in;iudin: Etittt:tririrtt'

l)uru:iti.f(ru.\. that

lire

at the in-tcrliraL- bL-i\\cJrl

irr'ii,5i. llll!..rllit.roiria

sulilde-t-ttntainins

n'lunnr-:e.ilnr.-nts

tfigurc

2E.1lri,Dt. -l-hr'rc animrls are covered b1 sultidc-t

i;.lizing

b,ectcrilr

iililt

.rre

ri(\.nt

ir,

intncatc- pafierns ttigure

:\.

1 1 /) ). Thc b:rctcrii ni)t r)nl\ tir'.rcirrc ler els of

toric

sultlde. rl hich

(1itdn \Urrcr,-rnLl

thJiteillltode:.

irllt th!-\

llso

sen-e as a t-ood supplr.

In

I 9!)i r. hr t1r,,',i::r-nlrl 1

3

.

\\ r-i'i Jr:covered

in

a fieshu atcr

cni

ilrnrnciri.

at titi''t:r.rttonr

oi

L-lrke Ueikal. the oldest (15

million

-\u-ar':

oldr

rntl

iir'c'p::rt lakc

in

ti.-

uorld.

This

lake

is

located in

th-r far

cr\i

()1

Ru..i:r

rfigure

28.1kt.h.cl

and ha\ the largest

vol-ur,-re

ol'an\

ire sh\\

rtcr

lakc (rt()t

litr

'rrgest

area-\\.hich

is Lake

Sup.'r-ior). Thc

hlcterial gplrriih:.

uith

ltrng

r"hite

strands. are in th!. ecntL-r r.r1'the

rr-nt

f

ield

,,ihc'rc

thc

,righest

tclrperaturcs

are

ior,rnd (t'igurc 18. I

li

i. At tltr- .d

!c

()t'th.

r ent

tlcld.

ri here thc \\'a-tar te rrperrti.irc

i'

liri.er.

thc

brite

rill

nrrt ends. and sponces.

gas-trlirlils.

rrr,l

otlie

r

. rrgirlli\t11.. ',r

lliilt

:.

.i tit:

:uliur-rlridizing

bactcria 11 1 |irr,11 11

,r.;;---though

le ss

cicr.l(,i).d

Lake. \\"r'e,nrin!:.

A

hr r-irogci:

.Lliil,i.:

',.rrt.i

'.'a, !\-',

\i.ll'.

lr.r\

h:iiil tii:.'ilr

crc.i

tti Southem Ri,ttt:rltili titui

i- -1',.:r

tirl,:rr- [--l::l::

'.tl:1ii-C. (-l',es ili

thc area

contlin n1li.

L)t

nii-lL,or!nr.ti:ilr iirili

i:\

cirrh()n

dioxidc'u.in!

h) drogen sultlde

ls

lhc .1!-ctron 111 )n\lr. Fon-\ -ci-sht sp-'cic-s of car

t-ldrptcd

inr

cn.'5:-lic:

ilr.

\ir:i iri

ld(l

rt

\

iit

i.

jl'rc _nl()xLrt\ ltr!'lrhic

b]:a.

.-\

ittfill

()1'uil{)ll(fil'rir,ti iri.r} t}-.i-:t':

ril;:ir

_{li it(}pLlliilir)t)}

(]l'.int-ilar

nlier-tltlrsLrli:rll:

Ill,,-rii()i\ i:. \,\\Ii

r:.'ii.itr. lhc procc:r

o1'

quorunt sat)sinS. r', itich ri ir.

tiirJl-i..r.l

itt

.r--iiolt

6.-<.

l'ire

lrticrttrr-canisrts produ!'a specilri iliri(rin(iuaJi-c(,il)1 )Linii\.

lntl

_{ar the}

3rp-Lillriit,il incrcli..' trnti litc !!1it!aiililllir,:-r,1

liic.r'.irlltPirLinJs

rcacha\

criiical

1r'rel:.

.rrr.iiit i-rJs :i:r

.\Prd\:ci.I. l-lrcsc

rc-spon\cs

llrc

intn\)rltint

l\)i

illi.l-r)(\iL:inisn,.

ihitt lirrnt

lrrsociatirrnr

*ith

plants antl

ininral..

lurrl

Iliuli.ulxr'lr

1,,; hunran pilth()!cn\.

\1-rcorrhizai

t fungal-yrlerrt

r(ii)i

intcr-:lalir)n\)

prc\cnt

u

\pe-cial

casc c.rf a ci,opcreti\

c lL-ilili(rn.hip

i .3s- chapte

r

-1() t.

"\or-Inal"

chlorophr

ll-contrrinrnr Ii1n1. i:.;r

--rr,)\\

$

ithout

thc l'uncus.

plrrticularl\

in the rlee nhLru:e .

in.licutins thiit

this is not an oLrligat()r\ rc-1:rtion:hip. Sonrc 1unqi.

ln contra\t.

d() n()t

sur-rircuithoLttLrJil{u.\().ililttl

',',;ti,lrIi.1',1

l-hcu.lll',tlirirrlloLi:

i.

l::-' j)re \-:

ji

,ll:::r lr 1}

,- Silrtilar

;"ri-lirclL:

hrr

t

ir.:cir

lr)un!1

in

Ycllou'slcrnr'

l-Frolikha

Bav

Lake t'

5aa

(c)

Figure

28.12

Hrclrotliernrul

\ent

l--eos-rstems

ilt

l.'resh*uter

Environntent.s.

Lake

Ilrikal

r

in Rlr..ili

r

lli:

hce n tirunti

ii,

irar c

lo*

tentperliturc

hvdtort-:rnrlil

r.r'tt\.

t:l)

l-ocutiorr

oi

L,lLkc

Blikal.

sitc

oi

the

hr drL'rhcnnul

r:nr

ilcld.

rb

r

lJactcriril

nrii

near

the

ccnt:r

o1'

thc

...n1

_tie

itl.

rc

r

Iltrctt'riul lllurntnt.

unrl sPt)nSes at thr- adsC o1'tit.:

rcnt

i'ititi.

/iri.\,/t//i.

l)riiti

tnttrt tlit \'.rri, t:.tl C,

,,r

. . '

\,,

Chaoter'

28

lilrcr-oorganism Interactions

and Microbial

Ecology

5.

28.1 2

monotropoid

plants _{(scr, 1t.} 656). horvever. are

dilt'ereni.

These plants depend greatl), on the

llycorrhizal

funeal net\\,ork ro pro-vide nutrients

"taken"

frorn other

chlorophl ll-containinS

plants.

1.

What structural features of the rumen make

it

suitable for a

herbivorous type of diet? Why does a cow chew its cucj?

2.

What biochemical roles do the rumen microorganisms play in

this type of symbiosis?

3.

What is syntrophism? ls physical contact required for this rela-tionship?

Why are Alvinella. Rimicaris. and Eublstric,tus good ex::r.lples of cooperative microorganism-animal interactions?

Where is Lake Baikal located, and why is this unique

rr

ierms of its microbial communities?

6.

Why do chlorophyllous and achlorophyllous plants have differ-ent degrees of dependence on mycorrhizai fungi?

Commensalism

Commensalism ILatin

(.)//1. to-sether. atrcl

nlt,it.rl.

tab]r-l

i:

u

re-lationship in u'hich one

sr,nrhiont.

the

comnrensal. :;nc1rr:

*

hile the other (sontctinrcs callcd the host)

i\

naithe r hrir;::e.i nor hclped. as shou n

in tlgule

lS.l.

l-his

is li Ltnitlirectionlil r:,r.-cs..

Otien

both

1't- ''a' t

I t,' Il,- r

rit-

l.

1,.,1

r^i.

ti. ihc \...1..

:

'rla."

I-hc

spatitl

prorintitl

Lrt

llie tir()

put-tltci'\

I.tl-;lits

the

.:,:t-.ilr'rr-.lrl

ttr

lced

!)il \ulr\llnae\

altJrtLrfaLl t,r'iri-9c:i.:.1

br

tite

i:,.i.

llnri thc

comntenial

ol'tcn obtair.r: shcitcr b-r Iir i:t:: tithe

r,,n ,.:

:n thc host.'fhc- corr-intcrr:lil

ir

not

dircctll

clcpenclr.ni ()n thc

lt{,-:

ntflli-boiicallr

and caLlsL'\

it

no palticrrilir

lrlrnt. \\'ltcn

tite e()ii-..1-iJnsll

i:

separatc'd

iront

its htrsl

cxpcrintcntlillr.

ii

crr|r :rrrr

ir.,

...

ititi,itl

hcing pror idcd sr-rnte t'rctor or f iictttrs

oi'Ittrsi

rr;

itin.

Conrnrensalistic

rclatitrnsliips

[.etrr

c.-n

rjti.l-,,, ,r

-!lLir

-

.

,:

in

iludt

sitr.rations in

*lti.:h

titc \\11.ia pr()rlLtet (r: Lrit;.

nliLl{.,.'i.rtri.i.,

ir

thc subsireir'tiri'anrr:hi.r sP.-i::'.. L)lt-:

tt,,,.i

U\-iiltIle ;.

:t.::iii,.,,-lrrrn. thc oridatton ot arrtn.l(rrtiurri ir)n t()

ltitritc

i.) nIri,,,,--_.i:l\nl.

:uch

3\

\tilrut:otttoiltt.r. lrntl thc

\!b\cLilrcitt

t,tij.:iioi.r ()l-riJ lltlriic

Ir)nitrJtehr

-\'irrzrlrrrr'llrantl

siltillrhuetcrill

t..r-t

i)lt.7r.\-.'-,r..\;,

inrixtcter henctlts 1rtln;

ri:

lrssiit iull0rt

\

itlt .\'rlr|r,ri?(/,f :.r,.\

^l!]U\e

il

Lr:c: nitritc ttr

obtlin rncrS\

lor::r'truth. ,-\:C-rriiii e

rlintl.:

,,l tltir

tvpe

()l'relationship is

fbund

in

.rn:ierobic ntL-tilunr)lcriiu

=-,,\\

\-lc'rtt\ SUCh a-s sludge digesters (.r(,(, .\(,('/1r,i 1

ltl./r

r. lLr.ttrcrol-l: il-c'slt

\\ atcr Jquiltic seditttcnt.. anrl tlootle rl

:cil:.

ln tirc:c e rrr ir,,..-lr-nls.

iuttr

acids cun r-+ dcsnrrlctj ttr jtr rrrluce

H.

antl iltcthuna ir..

:ltt

in-tcnleti()n o1'trrrr

rlillcrcnl

hltetcrirrl tr()ups. \lc,titane

protlii.:r.,n

br nlcthanogcn\ dtpcn,.i. t,n interspecic.s h-r'drogen

translcr.

.\

lcr-nle ntati\ c hactcriurn

!ancilrlc\

h\ !ln,gan Llis. i-inLj thc rilcLi:..:,.r-gcr;

tr:es it quickl-r

J\

lt

\ub\lrillt'

lor-ntctiilute _{-!lt\ irr\)LiLlctii)n}

Various terntentatir c bactcria protiuce i().,\ ntol!.e ulr:r '.', _JiSltt

lattr

acids

that cltn

hc

desrailctj

[rr lnucrol-i.

hticteriu

-:.ait

ir\ SvtrtroltltohaL

lcr

io

produce

H. a: lirliou

s:

Propionic acid

+

acetate

+

CO.

-

H,

St'tttropltobut'Ier- uses protons (H

- +

H-

J

H. ) as ternrinal

elec-tron

acceptors

in

ATP synthesis. The bacterium

gaini

surilcient

(a)

lyrt4-.

fotdW'gl-ttvt

re

4

1

f,r.,lM

\

{..*"L\v

W)*t<rv'

'J'--8*ltbp"t

*y

energv tbr grorvth

onlr

u'hr-n the

H.

it generiites is consunle.l. The products

H,

ancl

CO-

are usecl

bv

tllethanogenic archaea te.g.. lvlatItatutspi ril/trrrr)

a:

tollou's:

-lH.

+

co,

--+ CH.*

+

lH.O

B1 s-rnthesizing Itrethane. Mellrttrtrt.tpirililrrrr

ttraintlitls

a

lt-q'H'

concentration

in

lhe

ilnnlediatu-

enVirotttllellt

of

htltll

bacteria. Continut'rus rentoval

ot'H.

prornotes furtirer

fattl'

acicl

f-r'rtllentil-tion

anci

H.

production.

Because increased

H.

production

and consumption stimulate the grorr,'th rates

of

S.t'ilIntpItrthttttcr- and il[ e t hu n o s p i ril1rorr. both particiP]nts i n the re lationsh i p br-nefi t.

Conrmensalistic associations also

occur

when

tlrle

tlricr,rhial group nrodifies the cn\.ironrllent to make

it

tllore suite,-l for

lntrtiter

organism. For eranrple. in the intestine the ctrtt-ttt.ttltt. nollPathouellic strain of Eschericltiu

trrli

lives in the hurnan colon. btlt ltlstl

srous

quite u'ell outside the host. and thus is a

nprcal

corllnletlsal.

\\'hcn

ox\'-qen

ir

used up

bt

the tacultativelv anaertlbic E.

t'ttli.

trbligate anaerobes such as Bcrctentides are able to Sro\\'

in

the colon. The anaerobes benet]t

tiom

their association

uith

the host and E.

toli.

but

E

c'oll derives no obvious benetrt

liom

the anaerobes.

[n

t.h;s

c&se the commensal

E

Cr.,1i contribuies io the ri eltare trl- other

sYm-bionts. Comnrensalism can involve other cnvironnlental

nltvjitlca-tir.rns. The svnthcsi\ o1'acitlic rraste

Irt'ltt'-':

cluring

lcrnlentrtiotl

stinrulate the prolileratitrtt o1'llrore acid-ttliL-r.rnt

illiar('\'l--iil,\lll\.

rrhich arc

onlr

a lninor part of thc nlicrobiai ct,rntttiuniir xt Il.'.rtl'i.rl

pl{s.

A

scxrt! exarnple is the successitln c'rI

nlicroorgitni.trl: ililring

rnilk spxtilage.

A:

ittitrthcr exalnpie. rl hen biolllms

trc

lonrl:i

t

:ec-tion lti.-1 ). the colonizrtiott of a neri

ll'

e.rpo:etl surilice

br

orre t} pe

ol

nricroorganisnr (an

initial

coionizer) nlakL's

it

pilssiLrl.'

tilr

c'iher nticrtnrganisnrs to attach to thc

nlicrobiaill

nloclitieri

:uri-r.tce

t'

Cornmensalisrtt

alro

is itllportant

in

the

colorlization

oi

ti,e

hun-ian

bodl

and the surfaces cll'other unirnal: and plant:. Thc rni-crrxrrganisnts assoeialed

riilh

ltn

anirtlal

:Lin

ani

i'L'dr

t'riilit'

aan Ll\c

rolatilc.

strlublc. and panicr.rlatc t'rSlrltie ao:l)Ir()i-li'ld\ ii-()n1

rhe htrst as

nutricnts

I see sectitttt -11.1t. L'ntle

r III()\l

condilion\

there nticrobes tlrt n(ri cattst-' hltrnl. othc'r thlin

pos:ihlr

contrihLtl-in-r: to hrix11'uior. Sontclintcs

$hcil

the

ho:t trrglni-':tl

i::ire::crl

or thc skin is punctured. these

nornllllr

ctrtt.tltlensli

lnicroorgan-isms

nrar

bcconie

palhogcnic. These interactions

riill

be

dis-cussed in chapter 3 1.

1.

How does commensalism d!ffer from cooperation?

2.

Why

is

nitrification

a

good

example

of

a

commensalistic

process?

3.

What is interspe(ies hydrogen transfer, and why can

this

be

beneficial to both the producer and consumer of hydrogen?

4.

Why are commensalistic microorganisms important

for

hu-mans? Where are these found in relation to the human body?

28.1 3

Microbial lnteractions

Predation

Predation

is a u idespread phL-nomenon u here gulfs or attacks the pre). as sht)* n in figure 28. I

(a\ Bdeilovibrio

(b\ Vampirococcus

(c) Daptobacter

Figure

28.13

Eramples

of

Predatory Bacteria Found

in

\ature.

tal

Bdcllovibrio.

a peripla-srnic predator

thlt pcnctrrit.

rhc'

ceil

uall

and grou's outside the plasma menrbrane.

(bt

li;r,;

;,jp,i

1r1-1'11.s x ith its unique epibiotic nrtxle of attackinS

l

prcr

lrr,i-lcriunr.

and (c) Duplobacler shou'ing its cytoplasmia ioeltlir,tt

l:

it

rttlckr

x su\ceptihlc bacteriunt.

lrrser

or smaller ihan the predator. and this nomrallY re\ults in

th.

death

of

the pre).

An interesting arra)' of predatory bacteria are acti\ e itr trrtLtrc. Sereral

of

the best exanrples are

shoun in

tigure

28.13. incltrd-ing

Bdcllovibrio.

Vutrt1tiroc'occus, and Duptobactcr: Eech of tlte

:c

''lt\

a

unique

mode

of

attack

against

a

susceptible hactcrituir.

Bdellovibrio

penetrates the

cell u'all

and

multiplies

'oelseen

tlit

s'l-

and the plasma membrane. a periplasmic ntode

oi

attack.

fol-Irrrred

b1'l1'sis

of

the pre,'- and release

of

progenr

rsec.fi,r,urt'

l-1.-lJ

This bacterium has an interesting

life

cycle. u hich is

di:-cussed

in

section 22.4.

Nonl_,

tic forms

also are observed

.

Vampiroc'ttt'c it.s atlache:

to the

surface

of

the

prey'(an

epibiotic relationshipi

artd thcn

\ecretes

enz\.mes

to

release

the

cell

contents. Di;ptobacter

the prcdator

en-The prt-'r' e an be

t :,'.

:

Cl-.apier

28

Microorganism lnteractions and Microbial

Ecology 28.1 4

The Many

Faces

of

Predation

te 5i irr n

-'te ntion

.ri!'clion and increased fitncss

The nricrobial loop. Soluble orgrni. nlriler tiont prirnrn pr()du.c,-\ i\ nLrnlirll) u'e.i br bacteria. $hich hcconre a prrticulale tirod siturce

for higher consumeF. Flagellates end ciliates prer rrn thr':c' h:r.lcri.r rrnil djr:rrt thrr':t. rrakin-c the nutrients they c()nl3in available again in

mineral form for use in primary production- crc-ating th!- nllgsqrir irrl l1r _'p. I'r tlii: rr :r r larle portion of the carbon fired b-v.' the

photosl.nthetic microbes is minerelized and rc'c}cletl (thu: tht tcrrr rriicrr,l.ill lot,pi rtnd d(^-s nr)t reach the higher trophic levels of the

ecos)'stem lsee _figure )9.J r.

than *'ould rrccur if the predator \\ ere not a.ti\e.

Bacteria retained s.ithin rhe predaror serve a useful purp()\c. ris in lltc trrl.iLrmriru(';', .ri toric h)drosen produced by ciliatcs in the rumen

toharmlessmethane.Also.trapping()fchloroplasts(klcptLrirlrrroirlr\l\ib\ prolo/,riiproridestheprc'clatorlvithphotosl'nthate.

The intracellular sun'ir.al of Legionelltt ingested hr ciliatcs pr()tccL\ it li,,i.-r :lr.\\d. \:.h as heating and chlorination. ln-gc'stion also results

in increase6 pathogenicit), when rhe prel is again rele rscd 11r tir. . \ l.in-:: ctt r r ronn::nl. and this ma1' bc required ftlr infection of human:.

Tbe predator sen'es a-s a resen'oir host.

Nanoplanktonmaybeingestedby'zotrplanktonandgro$ inthcl()Llil.rftL1.,udigcstire\\stem.Thc)'areth!'nrelcasedlotheenYironment

in r t'itter state. Dissemination to neu locations also rtccur..

ietrates

a

susceptible host and

uses

the

c)'toplasmic

con-ts as a

nutrient

source.

Ciliates are excellent examples

of

predators that

engull

their

\. rnJ

based on \\'ork $ ith

fluorescenll)

marked pre)' bacteria. 'r-rle

ciliatc

_{can in-sest 60} to _{70 Pre)'} bacleria _Per

hourl

Preda-I

on

bactL-ria

is

important

in

the aquatic environment and in .irS!'

trcltnrclrl

\\here

thc ciliates remo\.e suspEnded bacteria

'. _{har c- ntrl sr'itled.}

.{

:rirpririnS tlnding

is that predation has

man} bcnellcial

c1-l:.

crpr'ciullr

uhen

one considers

interactil'e population\

()t'

.-i;.i'rrrr: unii

prc\.

as sumrnarized

in table

2t1.3.

Simplc

ingc':-r

lnJ

lr\\iiiliiation ol

a

pre)

bacteriunr can lead

to incrt-rt'trl

r*r'l'

n1111'1.'i11

clciing. critical tbr

the iunctioninq

ol'the

rni-,hial

ltxrp

r tt't'

st'ttirttt

29.1 urul

figttrt' )9.1).

In

thi:

prtrcc-".

.r.ri.

ntriiir-

produced

through

photos\nlhetic and

chcnl$-.hr;

rr;lir

ri\

is

n)ineralized belore

it

reaches the

hi!hcr

corr-'i-.'ir. 3li1ru ing the mincrals to be made arailable to the

Prillrrn

.1ii,l;-.. in

u "itxrp."'

This is important

in

ircshu;rtcr.

nlltriil.-. r

igrc.irilri

.n\

ironrncnts.

Inccslion 3nJ

\hon-icrlll

retL-nti\)11

'ir!.t.ri.r .i!..,

are

critical for ciliate functioning

in

the

runlett-lrr

rnrthxnLrgcnic bacteria contribule

to

the health ol"Ihc

ciii-.

L'] decreasin-s toxic h)'dro-sen levels through usine

H'

to

prt'-re .,]ethrne.

\\hich

then is passed

tiom

the

rumen-Pr.-ilation also can provide a protective- hieh-nutrie nt etlr ir.'i'l-nt i()r panicLrlar pre)'. Ciliates ingest Lr',qirrnt'lltr and protc'ct

thi:

ronlnt

paiholen from

chlorine.

uhich

orien

i\

u\eJ

in

an

at-'tp'i _{t(r c()ntr()l}

lteit)nellu

_in cooling to\\'ers and air-conditioning

t:. L;c

ciliatc

sen.cs as

a

reservoir

hr):1. 1,2'1j1t11a'1111

ltrit,it-,'rltrltr also lias been tbund to have a sreater potential to inrade

.r(rphr,!is

and epithelial cells

atier

predation.

indicating

that

e.Iion

not

onlr

provides protcction but also

nlar

nlakc the hac-unr a betle. ,)uthogcn. A similar phenonlenon of surr ir al in

pro-rra has hccn rrbserred for !v'{vobacteriunt avirrrrr. a pltthogen ()f

rltlrridc

conccrn. These protective aspo-cts

oi

pr.'dlltion

harc

jor

intplications tbr survival and control o1'di:eatc--e uLtsipo

p11-,()rglnisnrs

in

the

biofllrrl\

f

rc\ent

in

rr

rtr'r

:rrpplies

and

air-contlitroning

s\

stenrs.

In

marine

s)'stems

the

ingestion of

rllilr,,rplenktor.r

bl

zooplankton provides

a

nutrient-rich

enYiron-nr!-lrt thirt allo$ s nlnoplanktcrn reproduction in the digestil'e tract Iili(i _irl',\nlote

\

dis.enrination in the enYironment. A sinlilar process

i

ri;::i' llir-i

bli;trnu

rrc

ing!'\lL-d

b1

ptlll'chac'tes (segnlen!!-d

\\ r,: Ill\ li,ul'ti ttt, r.ll) ll) Il)lrnllC CnvirollmCnt: l.

I'r:;l'ii i,li..n

sl',,,,,i

intereslinr

prc-riatorr skills. Sonle

lunci

can

ii.:i:

i',:(1'.()1\r:i

irr

li-,r'u:r-

rli

rtiekr

h1 phae

or

knobs.

stickl

n':t-r,.

' :i.. t,i

lt', rhac. {)a

i(\n\trii--ling

r)r

nonc()n\lrictinl

rings. A

cles-\ia

e

\.:ilniria

t>

.\,t:i;rttltrtins.

\\'hich

traPs nenlat()des

b1

tlsL- ol'

.i,it:ii-ictinl

l.ir;-1..

.-\ticr thc

nematode

is

trappcd. hvphar' grou :t

:,

.

.

rrrir: ,"il;/-'J

prcr

und the

clt0plarnr

is used as a

nlltricnl.

(

)ir.';

_{tirnSi hur}

t

i..iriJia

_that. af ier incc'stion hv ltn un:urpc'cting i1.ir\. ,jt.,\\i. :,itrj trii.r.jl,

th.:.u'ceftiblg

fiost I'rrrnt inside tlrc

intcs-i;;r.ii

iiit!i.

i:,

lit;. .;lulrii'ril Ih.

Iun-gus

p.'nclrliia\

thc

htlrl

ccllr

ir-t

li. '::,Il-'1

:j

iai:r-'.:\- ff(\a\\

I

iru.

pre

tliriir.i:.

u hie h

u.uiill)'

has a l'atal and

tjnal

outconle

i,';

,:r

in.1ir;!irilrl

i.i.\ (,r-!rni.nl.hasauitlcrangcof

henct-icilrl

cl'-' cl'-'. ,:,

_{!,._ :'}

,'

.'r,\ir\.

_lrn.: r. critie:rl ln

thi

l'utltti()tlin'j

()l n;rl-tii:!l en\ irir;lrtlitli..

Pa

rasitis

m

I'arasiti-snr !s onr

ol'thr

rlrost eLlntple\ nricrobial interaclions: the

lin.'

h.'rri r-cn pararitisrn and predation is

difficult

to def rne

tlig-Lrr.

l:i,1.

'ti

,r/.r,, .\('(ti()n _-iJ.

lr.

l'his

is u relationship

in rihich

()nu

rrl'ri

irilir bdlr.flts tiont thc

othcr.

and

the host

is

usuallY hrr-nrr:ti.

l-hi.

rrin

ir.:r,rlr

c

nutrient acquisition

and,/or

phr:ical

nririn!alllnlc

in or on tlie- hosl.

ln

parasitism there is a degree

ol

ci'e r.isicnie r)1'th. p.lrasite

in

a:sociation ,'r'ith the host.

Depend-ilrl

on the ctlrriiihrir-inr betueen thc

tuo

organisms. this ma1'

:hift

anrl ri Irrt rrriSht hlir c becn a \tablc parasitic relationship ntav then bccoilr.'

r

prth()sL-nic one \\'hich can be dellned as predation.

Microbial

lnteractions

591 28.15

Figure

28.14

l-ichens.

Crustose (encrusting) lrcherlt gro\\ rns

{,11 ir !

l:!nili

Po:t-:,r\iJr 1rr!,!lilation

hr

Crrnrrellocleritutt

tliphtltcriut (\"t

\"(Irr)/r\

,'-.-i

,,,,,,' -i+--i

t. itai-eriiic

fungi

include

Rhi-oplttdiurtt

spltttttti-.ir.,ri.r,r. .,',

rllt

rhe

llLl

.!;,.r'rp1,.'

1i. ,\l:'.'.

Rlri:.octt;ttirt sr'/itrri

i'

lt

a,,,,.,,.',. r,i'

l/:tt

lt-llllti

P.r'I/titirrl' u hich

i:

itllport:rnt in

triocontrol

1rr,ra"rt"r.

iiir-

tt'i'

rrj li;11- 111i611 _{'rrr!lLIlislll}

ltl

Crrntrol an()thct-

Hr'l-,;t,,ii

.::..-..:' -iiil.ari

irq

i

i111sgr. nlicletia. l'ungi. i1nd pr()t();/()lt

ltr'

l-iehens irle

til.

:-l:\(t.iJtion {L*l\\cen r1e-cilic

a''eolll\ccte:

(ih!'

l.:n-!:ii.

.:i,!j .lil-1lliir rana:-li oi-

'lihci

!:rL-'n algiie ()r L\ itnrlbitctcriit'

i,t,,

li.i",'.111r

lu:lSr'i _irlll1 ncr

i\ l'rllleJ

the

nllcribiont

und tlle

li--:..r1

i'r -\iril,'a,li.tirilil

f:11111cr- rht-

phlcobiont'

[-icht-'ns

i]rL'illl

c\-..iic,,t;r.,r,1lie

t''t

ii

c()rllrolied parlt:itisnr

ttigure 2ti'lJl ln

thc

ir:!\tti)cliilicn.rnltrio\i\\\'as(jollsideredttlbeanlutualisticinler-,,-li,,l.

ir iirLtn,rl\ he. i'ccrr lil,rnJ thlrr lr lichen \\

ill

i()rlll

t'lilr

shcn

',ltr

iiio

Ir\riarlljlti fr:il-rllcir ',13 nr;1fi1iottltlli

dcprired

Untlcr

tltlrtltll

-,,;,,liiti,t't. lllc

l)t)tanlilrl

f.lnncr'

:'1rcll't interl-sted in each

uherl

-fltl

rcrllarkllhlc illpe.l ()l lhi) ll::ociatii)n is

that

it:

ttlor-'r1,,11,,1.. i.iit.1

tllatilt'()lii

i"e

iatit'il'hif \

are so c()nstant that

lichcn'

.,:. tr..i:rtr'J 'lallil'la

iirrrl

'Pccir'' Il:tlllc\'

'l-hc

chl'rlrclr--rirtit

tll"r-:r,,,i.,1r

,,1

"

lit,:rl

liche rl is x

!l()pert\ tlf

the asstlciatitln and

is

:r'.r

.'rhihireLl

br citilc; srtrllionl irldiridtralll''\':

:

ilte aute rhe phr coiriont

i\

a ph()tL)autotroph--depcndent onlr

,,r

lirht.

earhorl

tliori,lt-

lrnd cenain

nlinerll ntltrients-the

l'un--,.,r J,,,, qct

it\

()rqunic e lrb()n

directlr ironl

the aiga or

cr.anobac-1., i,,,,r.

Tlrt

lLrtlgus olte

n

ttblirins llutrients

frorn

its

panne

r

b\ hlrurtor-ia

lf

roicctions o1' l-unqrl hvphae) that penetrate the phl

-Cr\tir.ri.tI

ccli rrull.

lt iil\o

Llsc\ thc

o.

ploclscer.l dtrring pfi1'cobi6nt

Irl-i,)ir)lth()\iittr;t

llitigtt

itt e .trtr

itr!

,rttt I'Cipirlllir)ll. In turn the

ful-rr.t\

prolccl\

tIc

pltr cLriri(.)ttt l'l'prlr high

light iltensitits.

prgyi'-1es

r,. .::r-f

lllttl

,,'rincrals 1.,

it.

lilt(i

cielltts ll t'irtll

strhslr'atutrl $

ithitl

\\

:'rJh thc

i.it)

c0hiotll

ciill qr()\\

Pr()tcctcti

frrlitt

c-nr irtlnnlentel

\itj>\.

-f

he

-,i.ilin'

ot-thc tirtlsLt: to pal'asitizc' thc' alga or

cvanobJC-t.;-iulil undir

\Llch lonscr-tcl't'll ctlrtditiotls alst'r has bec'n tlescribed

ii:

.r

li)rIIl r,i

ir-rlt gal -,.i i rL-ctccl "ili gliclr I{ trre

"'

.\tr

irttp.,rtlitlt

rsJ'eit

o1'I)lil'ilsitisll'l is that tlr't-r

tinle'

the

para-.il;'.

trttce

it hls

cstahlishc-il a relatiorlship r'r'ith the host'

\\'ill

tend to .1i:cat'tl e \ccss.

tilttt:cil gcllolllic inf