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bacterial symbionts

Alejandro Manzano-Marín, Gitta Szabo, Jean-Christophe Simon, Matthias Horn, Amparo Latorre
Virtually all aphids maintain an obligate mutualistic symbiosis with bacteria from the Buchnera genus, which produce essential nutrients for their aphid hosts. Most aphids from the Lachninae subfamily have been consistently found to house additional endosymbionts, mainly Serratia symbiotica. This apparent dependence on secondary endosymbionts was proposed to have been triggered by the loss of the riboflavin biosynthetic capability by Buchnera in the Lachninae last common ancestor. However, an integral large-scale analysis of secondary endosymbionts in the Lachninae is still missing, hampering the interpretation of the evolutionary and genomic analyses of these endosymbionts...
November 30, 2016: Environmental Microbiology
Pierre Dupuy, Benjamin Gourion, Laurent Sauviac, Claude Bruand
The soil bacterium Sinorhizobium meliloti, a nitrogen-fixing symbiont of legume plants, is exposed to numerous stress conditions in nature, some of which cause the formation of harmful DNA double strand breaks (DSB). In particular, the reactive oxygen (ROS) and nitrogen (RNS) species produced during symbiosis, and the desiccation occurring in dry soils, are conditions which induce DSB. Two major systems of DSB repair are known in S. meliloti: homologous recombination (HR) and non-homologous end-joining (NHEJ)...
November 23, 2016: Microbiology
Hsiao-Ling Lu, Chun-Che Chang, Alex C C Wilson
BACKGROUND: Many insects host their obligate, maternally transmitted symbiotic bacteria in specialized cells called bacteriocytes. One of the best-studied insect nutritional endosymbioses is that of the aphid and its endosymbiont, Buchnera aphidicola. Aphids and Buchnera are metabolically and developmentally integrated, but the molecular mechanisms underlying Buchnera transmission and coordination with aphid development remain largely unknown. Previous work using electron microscopy to study aphid asexual embryogenesis has revealed that Buchnera transmission involves exocytosis from a maternal bacteriocyte followed by endocytotic uptake by a blastula...
2016: EvoDevo
N P Havill, J Elkinton, J C Andersen, S B Hagen, Hannah J Broadley, G J Boettner, A Caccone
The European winter moth, Operophtera brumata, is a non-native pest in the Northeastern USA causing defoliation of forest trees and crops such as apples and blueberries. This species is known to hybridize with O. bruceata, the Bruce spanworm, a native species across North America, although it is not known if there are hybrid generations beyond F1. To study winter moth population genetics and hybridization with Bruce spanworm, we developed two sets of genetic markers, single nucleotide polymorphisms (SNPs) and microsatellites, using genomic approaches...
November 23, 2016: Bulletin of Entomological Research
Eleanor R Heyworth, Julia Ferrari
Many insects carry facultative bacterial symbionts, which provide benefits including resistance to natural enemies and abiotic stresses. Little is known about how these beneficial phenotypes are affected when biotic or abiotic threats occur simultaneously. The pea aphid (Acyrthosiphon pisum) can host several well-characterized symbiont species. The symbiont known as X-type can protect against both parasitoid wasps and heat stress. Here, we used three pea aphid genotypes that were naturally infected with X-type and the symbiont Spiroplasma sp...
2016: PloS One
Aline Sartori Guidolin, Fernando Luis Cônsoli
Aphids are well known for their association with endosymbiont bacteria. Almost all aphids harbor Buchnera aphidicola as an obligate symbiont and several other bacteria as facultative symbionts. Associations of facultative symbionts and aphids are quite variable in terms of diversity and prevalence across aphid species. Facultative symbionts can have a major impact on aphid bioecological traits. A number of factors shape the outcome of the facultative symbiont-aphid association, including aphid clone, bacterial genotype, geography, and host plant association...
November 21, 2016: Microbial Ecology
Juliane Wippler, Manuel Kleiner, Christian Lott, Alexander Gruhl, Paul E Abraham, Richard J Giannone, Jacque C Young, Robert L Hettich, Nicole Dubilier
BACKGROUND: The gutless marine worm Olavius algarvensis has a completely reduced digestive and excretory system, and lives in an obligate nutritional symbiosis with bacterial symbionts. While considerable knowledge has been gained of the symbionts, the host has remained largely unstudied. Here, we generated transcriptomes and proteomes of O. algarvensis to better understand how this annelid worm gains nutrition from its symbionts, how it adapted physiologically to a symbiotic lifestyle, and how its innate immune system recognizes and responds to its symbiotic microbiota...
November 21, 2016: BMC Genomics
A S Meseguer, A Manzano-Marín, A Coeur d'Acier, A-L Clamens, M Godefroid, E Jousselin
Symbiotic associations with bacteria have facilitated important evolutionary transitions in insects and resulted in long-term obligate interactions. Recent evidence suggests that these associations are not always evolutionarily stable and that symbiont replacement and/or supplementation of an obligate symbiosis by an additional bacterium has occurred during the history of many insect groups. Yet, the factors favoring one symbiont over another in this evolutionary dynamic are not well understood; progress has been hindered by our incomplete understanding of the distribution of symbionts across phylogenetic and ecological contexts...
November 14, 2016: Molecular Ecology
Lukas Rothacher, Mar Ferrer-Suay, Christoph Vorburger
It has become increasingly evident that many organisms rely on microbial symbionts for defense against natural enemies, but the ecological importance of defensive symbionts for natural communities still needs to be investigated. A well-known example is Hamiltonella defensa, a heritable endosymbiotic bacterium commonly found in aphids. Laboratory experiments have shown that H. defensa strongly protects aphids against parasitic wasps (parasitoids), although this protection is not equally effective against different species of parasitoids, or even different genotypes of the same species...
July 2016: Ecology
J Elijah Powell, Sean P Leonard, Waldan K Kwong, Philipp Engel, Nancy A Moran
Animal guts are often colonized by host-specialized bacterial species to the exclusion of other transient microorganisms, but the genetic basis of colonization ability is largely unknown. The bacterium Snodgrassella alvi is a dominant gut symbiont in honey bees, specialized in colonizing the hindgut epithelium. We developed methods for transposon-based mutagenesis in S. alvi and, using high-throughput DNA sequencing, screened genome-wide transposon insertion (Tn-seq) and transcriptome (RNA-seq) libraries to characterize both the essential genome and the genes facilitating host colonization...
November 14, 2016: Proceedings of the National Academy of Sciences of the United States of America
Jun Ling, Hui Wang, Ping Wu, Tao Li, Yu Tang, Nawar Naseer, Huiming Zheng, Catherine Masson-Boivin, Zengtao Zhong, Jun Zhu
Horizontal gene transfer (HGT) of genomic islands is a driving force of bacterial evolution. Many pathogens and symbionts use this mechanism to spread mobile genetic elements that carry genes important for interaction with their eukaryotic hosts. However, the role of the host in this process remains unclear. Here, we show that plant compounds inducing the nodulation process in the rhizobium-legume mutualistic symbiosis also enhance the transfer of symbiosis islands. We demonstrate that the symbiosis island of the Sesbania rostrata symbiont, Azorhizobium caulinodans, is an 87...
November 14, 2016: Proceedings of the National Academy of Sciences of the United States of America
Jorge Morales, Sofia Kokkori, Diana Weidauer, Jarrod Chapman, Eugene Goltsman, Daniel Rokhsar, Arthur R Grossman, Eva C M Nowack
BACKGROUND: Bacterial endosymbionts are found across the eukaryotic kingdom and profoundly impacted eukaryote evolution. In many endosymbiotic associations with vertically inherited symbionts, highly complementary metabolic functions encoded by host and endosymbiont genomes indicate integration of metabolic processes between the partner organisms. While endosymbionts were initially expected to exchange only metabolites with their hosts, recent evidence has demonstrated that also host-encoded proteins can be targeted to the bacterial symbionts in various endosymbiotic systems...
November 11, 2016: BMC Evolutionary Biology
Ho Am Jang, Eun Sil Seo, Min Young Seong, Bok Luel Lee
Riptortus pedestris, a common pest in soybean fields, harbors a symbiont Burkholderia in a specialized posterior midgut region of insects. Every generation of second nymphs acquires new Burkholderia cells from the environment. We compared in vitro cultured Burkholderia with newly in vivo colonized Burkholderia in the host midgut using biochemical approaches. The bacterial cell envelope of in vitro cultured and in vivo Burkholderia differed in structure, as in vivo bacteria lacked lipopolysaccharide (LPS) O-antigen...
November 5, 2016: Developmental and Comparative Immunology
Katharina Kesy, Sonja Oberbeckmann, Felix Müller, Matthias Labrenz
Plastic is ubiquitous in global oceans and constitutes a newly available habitat for surface-associated bacterial assemblages. Microplastics (plastic particles <5 mm) are especially susceptible to ingestion by marine organisms, as the size of these particles makes them available also to lower trophic levels. Because many marine invertebrates harbour potential pathogens in their guts, we investigated whether bacterial assemblages on polystyrene are selectively modified during their passage through the gut of the lugworm Arenicola marina and are subsequently able to develop pathogenic biofilms...
October 28, 2016: Environmental Pollution
Hao Zheng, Alex Nishida, Waldan K Kwong, Hauke Koch, Philipp Engel, Margaret I Steele, Nancy A Moran
: Social bees collect carbohydrate-rich food to support their colonies, and yet, certain carbohydrates present in their diet or produced through the breakdown of pollen are toxic to bees. The gut microbiota of social bees is dominated by a few core bacterial species, including the Gram-negative species Gilliamella apicola We isolated 42 strains of G. apicola from guts of honey bees and bumble bees and sequenced their genomes. All of the G. apicola strains share high 16S rRNA gene similarity, but they vary extensively in gene repertoires related to carbohydrate metabolism...
November 1, 2016: MBio
Martin T Jahn, Sebastian M Markert, Taewoo Ryu, Timothy Ravasi, Christian Stigloher, Ute Hentschel, Lucas Moitinho-Silva
Assigning functions to uncultivated environmental microorganisms continues to be a challenging endeavour. Here, we present a new microscopy protocol for fluorescence in situ hybridisation-correlative light and electron microscopy (FISH-CLEM) that enabled, to our knowledge for the first time, the identification of single cells within their complex microenvironment at electron microscopy resolution. Members of the candidate phylum Poribacteria, common and uncultivated symbionts of marine sponges, were used towards this goal...
October 31, 2016: Scientific Reports
Kai Battenberg, Jannah A Wren, Janell Hillman, Joseph Edwards, Liujing Huang, Alison M Berry
: The actinobacterial genus Frankia establishes nitrogen-fixing root nodule symbioses with specific hosts within the nitrogen-fixing plant clade. Of four genetically distinct subgroups of Frankia, Clusters I, II, and III are capable of forming effective nitrogen-fixing symbiotic associations, while Cluster IV strains generally do not. Cluster II Frankia has rarely been detected in soil devoid of host plants, unlike Cluster I or III, suggesting a stronger association with their host. To investigate the degree of host influence, we characterized the Cluster II Frankia distribution in rhizosphere soil in three locations in northern California...
October 21, 2016: Applied and Environmental Microbiology
Kathleen M Morrow, Katrina Bromhall, Cherie A Motti, Colin B Munn, David G Bourne
: Pervasive environmental stressors on coral reefs are attributed with shifting the competitive balance in favour of alternative dominants such as macroalgae. Previous studies have demonstrated that macroalgae compete with corals via a number of mechanisms, including the production of potent primary and secondary metabolites that can influence coral-associated microbial communities. The present study investigates the effect of the Pacific brown macroalga, Lobophora sp., on coral bacterial isolates, coral larvae, and the microbiome associated with the coral Porites cylindrica...
October 21, 2016: Applied and Environmental Microbiology
Nicolás F Vozza, Patricia L Abdian, Daniela M Russo, Elías J Mongiardini, Aníbal R Lodeiro, Søren Molin, Angeles Zorreguieta
In natural environments most bacteria live in multicellular structures called biofilms. These cell aggregates are enclosed in a self-produced polymeric extracellular matrix, which protects the cells, provides mechanical stability and mediates cellular cohesion and adhesion to surfaces. Although important advances were made in the identification of the genetic and extracellular factors required for biofilm formation, the mechanisms leading to biofilm matrix assembly, and the roles of extracellular proteins in these processes are still poorly understood...
2016: Frontiers in Microbiology
Gwynneth F Matcher, Samantha C Waterworth, Tara A Walmsley, Tendayi Matsatsa, Shirley Parker-Nance, Michael T Davies-Coleman, Rosemary A Dorrington
The Latrunculiidae are a family of cold water sponges known for their production of bioactive pyrroloiminoquinone alkaloids. Previously it was shown that the bacterial community associated with a Tsitsikamma sponge species comprises unusual bacterial taxa and is dominated by a novel Betaproteobacterium. Here, we have characterized the bacterial communities associated with six latrunculid species representing three genera (Tsitsikamma, Cyclacanthia, and Latrunculia) as well as a Mycale species, collected from Algoa Bay on the South African southeast coast...
October 26, 2016: MicrobiologyOpen
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