Do Cyanobacteria Communicate With Each Other?

Bacterial CommunicationQuorum Sensing

• Important to perform group functions

• Secretion of toxins to kill competitors, production of luminescent compounds, etc.

• Small numbers of bacteria don’t activate their Quorum Sensing genes

Bacterial CommunicationQuorum Sensing

• Gram negative bacteria secrete acylhomoserine lactone (AHL) quorum sensing signals also called Autoinducers (AI’s)

• These molecules can easily diffuse through the membrane and are detected by proteins in the cytoplasm

• In this way the gram negative bacteria can communicate with each other

• When concentration of AI’s is high enough (numbers of bacteria are high enough) it can trigger genes to become expressed

Bacterial Communication

Vibrio fischeri

http://www.biologie.uni-hamburg.de/lehre/mikro/allgmi00/alg07f13.jpghttp://www.genomenewsnetwork.org/articles/2004/01/09/squid.php

Hawaiian Bobtailed SquidEuprymna scolopes

Light OrganContaining Vibrio fischeri

Cell Density

Time

growth

bioluminescence

Induction of Bioluminescence in Vibrio Fischeri

(Auto-induction)

Auto-induction in Vibrio Fischeri

LuxI

AHL’s

LuxR

luxC luxD luxA luxB luxE

Auto-induction in Vibrio Fischeri

LuxI

AHL’s

LuxR

luxC luxD luxA luxB luxE

luciferase

Autoinducerbinds

LuxR activated

Moves to promoterof luciferase genes

Gram Positive Communication

• Gram positive bacteria secrete small oligopeptides as their signal molecule

• The other bacteria have receptors for the signal peptides (also called auto-inducers)

• When the receptor binds the signal peptide it triggers the target genes

Gram Positive Quorum Sensing ABC (ATP binding cassette) transporter Recognizes GG containing sequence, Cleaves the peptide, and secretes it

GG

PP

sensor kinase- binding of autoinducer leads toautophosphorylation at conservedhistidine residue

response regulator- phosphorylation leads to binding of regulator to specific target promoters

HisP

D

ACTTTGCGATTGGCC

Peptide signal Precursor genes

Precursor peptide

Final Peptide Signal

How do you find what type of signaling cyanobacteria use?

• Are they similar to the gram positive bacteria?

• The gram negative?

• Or something entirely different?

Do Cyanobacteria use gram negative type signaling?

• The LuxI protein in Vibrio fischeri has a specific motif

• [LMFYA]-R-x(3)-F-x(2)-[KRQ]-x(2)-W-x-[LIVM]-x(6,9)-E-x-D-x-[FY]-D

• Search proteins of cyanobacteria for this motif = nil

Do Cyanobacteria use gram negative type signaling?

• Use Pfam to find the sequence of proteins related to Luxi

• Use conserved sequences to create a PSSM to compare with cyanobacterial proteins

Q9ZIU1_BURCE/10-189           .NAEWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-IHAHRA..G..PPK....q-V.DGRLV.VAC..Q9AM57_BURCE/10-189          .NAEWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-IHAHRA..G..PPK....q-V.DGRLV.VAC..Q9AM55_BURCE/10-189          .NAEWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-IHAHRA..G..PPK....q-V.DGRLV.VAC..Q9AM54_9BURK/10-189          .NAEWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-IHAHRA..G..PPK....q-V.DGRLV.VAC..Q93PD3_BURVI/10-173           .NAEWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-IHAHRA..G..PPK....q-V.DG---.---..Q93PF8_BURCE/10-173           .NAEWAVRP..ML.AA.AVECAAQLGARQLIGVTFASMERLFRRIG-IHAHRA..G..PPK....q-V.DG---.---..Q9AER2_9BURK/10-189          .NAEWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC..Q9AM52_BURCE/10-189          .NAEWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC..Q9AM53_BURVI/10-189           .NADWAVRP..ML.AV.VVECAAQLGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC..Q93PF5_9BURK/10-173           .NADWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DG---.---..Q9AM56_BURML/9-189           .GADWAVRP..ML.AA.VVACAAERGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC..Q9AM45_BURML/9-189           .GADWAVRP..ML.AA.VVACAAERGARQLIGVTFASKERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC..Q9AM44_BURML/9-189           .GADWAVRP..ML.AA.VVACAAERGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC..Q93NN9_BURML/9-189           .GADWAVRP..ML.AA.VVACAAERGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC..Q9AM42_BURML/9-189           .GADWAVRP..ML.AA.VVACAAERGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC..Q9AM43_BURML/9-189           .GADWAVRP..ML.AA.VVACAAERGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC..Q8L2M9_BURPS/13-190          .NLAWAVRP..ML.AA.VVECAARLGAKQLIGVTFLSMERLFRRIG-VHAHRT..G..PAQ....q-I.DGRMV.VAC..Q8KRT8_BURMA/10-190       .GGNPAWAVrpML.AA.VVECAARLGAKQLIGVTFLSMERLFRRIG-VHAHRA..G..PAQ....q-I.DGRMV.VAC..Q6UBQ0_BURPS/10-190       .GGNPAWAVrpML.AA.VVECAARLGAKQLIGVTFLSMERLFRRIG-VHAHRA..G..PAQ....q-I.DGRMV.VAC..Q6Q6F8_BURTH/10-190        .TGNPAWAVrpML.AA.VVECAARLGARQLIGVTFLSMERLFRRIG-VHAHRA..G..PAQ....q-I.DGRMV.VAC..SOLI1_RALSO/10-191            .RPDWAVRP..ML.AS.VVQCAAQRGARRLIGVTFVSMVRLFRRIG-VRAHHA..G..PVR....c-I.GGRPV.VAC..SOLI2_RALSO/10-191            .RADWAVRP..ML.AS.VVQCAAQRGARRLIGATFVSMVRLFRRIG-VRAHRA..G..PVR....c-I.GGRPV.VAC..Q9AHP8_BURCE/9-191           .ESWQNTRA..MM.SE.IVRVAHAHGANRLIAFSVLGNERLLKRMG-VNVHRA..A..PPQ....m-I.EGKPT.LPF..

Pfam search results for LuxI

Alignment of Conserved sequences for autoinducer synthase

(LuxI like proteins)

Comparison of s7942 protiens against Luxi-PSSM

• (#$S7942.p-Ser0724 (19 "LLQAASGLGAGLIVV" 1.1923437) (208 "RLAHWLDRGYSQIAV" 3.6059587)

• (#$S7942.p-Ser1616 (44 "AVLTAAPSSAAERIT" 1.884795) (294 "HVTTSARSFENVLVG" 63.0499) (409 "VAAVAADGLASDVFG" 2.342644) (431 "TVPTLIWGGSRDVVT" 16.80221)

• (#$S7942.p-Ser2323 (65 "IRKWNRELDYRLIKE" 14.655321) (77 "IKEVWAWHDNRIAVR" 3.8783476)

• (#$S7942.p-Sef2443 (51 "TGKPAWELRTPQIVY" 14.529033) (307 "SAKDQARLQANRLIW" 58.11094)

• (#$S7942.p-Sef2642 (5 "WVRCARLLKLCFCTA" 8.126585) (132 "VGEVAAERLTPAIAT" 7.601579)

• (#$S7942.p-SSELR002 (146 "IVASSSLNGIQQVVK" 1160.4387) (206 "NTAIAGGHGLTNSIT" 2.1221216) (229 "LIEYLVESGLPQDMA" 2.472199)

Results Name of protein, starting position of sequence, sequence, score

Do cyanobacteria use gram positive type signaling

• The peptides used in gram positive bacteria have a conserved GG leader sequence which allows them to be secreted by their ABC transporter

• This GG containing sequence has its own motif as well LSX2ELX2IXGG

• Searching cyanobacteria for this motif = nil

• Possible GG containing sequences found in other experiments

Do cyanobacteria use gram positive type signaling

Peptide signal molecules and bacteriocins in Gram-negative bacteria: agenome-wide in silico screening for peptides containing a double-glycineleader sequence and their cognate transportersbyG. Dirixa, P. Monsieursb, B. Dombrechta, R. Danielsa, K. Marchalb,J. Vanderleydena, J. Michielsa,.

MRELTLTEIDNVSGA MKELTQTEVMEVSGA NEELSTDELKSVSGG LQELSFDEIDQVSGA SQELSPQELANISGG IRELNEAELNCICGG TRELTENELEMTAGG FKELKENELTAITGG LKDLSEKELAAVFGG LQELTPEELEQIAGG LQELSTEELEQIAGG MQELSEEQLQATAGG MLELSNQELDYIAGG RQTLSDDELESVAGG RQTLSEDELESVAGG RQTLSDRELEGVAGG GRELSEEELESVAGG PIELSAEELDNVAGG PVELSAEELDNVAGG MKELHTSELVEVSGG MKELNDIEVTCVSGG MIELQLHELKLVSGG MRELTSNEMNNVSGG MRELTSIEMNNVSGG MRELTSYELQAVSGG MRTINDVEMEEVSGG MRTINAAEMEEVSGG MRTLTLNELDSVSGG MRELAFQEIENVDGA MRELVIQEIESVDGG VRELTVREIESVDGG MRELSKVEIEQISGA MRTELEIHEIESIGGA MRKLSENEIKQISGG MREITESQLRYISGA MREISQKDLNLAFGA MRELDREELNCVGGA LFINLSDEQQAFVAG LFINLSDEQQAFVAG LFMNLSDEQQAVVKG LFINLSDTQQAVVTG LFRNVSLEQQEMVVG LLADLSTEQQQFLVG LLEDLSLDQQQSLAG LLVELSTEDQQNLAG YLQDLSEQEQEIICG LFIDIYPEKSESVSG LFTQISVEESGVAAG EQDTLSEAELESVAG

Comparison of s7942 proteins against GG-PSSM

• (#$S7942.p-Sef1302 1280.0376 MQHLVDGDLAANNGG)• (#$S7942.p-Ser0408 1193.9419 MEERMTVCNMAIEGG)• (#$S7942.p-Sef2007 39.282513 LGPEASSVIQSIAGG) • (#$S7942.p-Ser0406 24.167059 AEKMMQAAWQEISGG) • (#$S7942.p-Ser1379 40.601192 YEQLLAPIYEWMAGG) • (#$S7942.p-Sef0291 (28.36743 FLSLLSRDQVQWQGG)• (#$S7942.p-Ser0724 (2.1610742 RQVVVHRHLGAMLGG)

(122.12031 LRQLPLDALGLVFGG)

This protein comes from an unknown gene it is small Like most Peptide signal molecules (less than 300 aa’s)So it could be a likely candidate for an autoinducer

Do cyanobacteria communicatewith eachother?

• It would be beneficial for them to do so in some cases

• Tricodesmium grows in clusters• Fixes N2 But not with heterocysts• Cells in middle of the clusters are Surrounded by much less O2 than thoseOutside the clusters• Thus N2 fixation can occur in this organism

Do cyanobacteria communicate with each other?

• Cant give a definate answer based on these results

• However there are sequences similar to both types of Autoinducers present in the proteins of cyanobacteria

What I would do differently

• Screen nucleotides instead of proteins

• Look for nearby ABC transporters for the possible GG-hits

• Search more cyanobacteria for quorum sensing systems

Thanks to colaborators

• Rakefet Schwarz Bar llan University

• Alex from Bar llan university

• Yitschak Friedman

• Jeff Elhai VCU