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bacterial symbionts

Maelle Sevellec, Nicolas Derome, Louis Bernatchez
BACKGROUND: It is well established that symbionts have considerable impact on their host, yet the investigation of the possible role of the holobiont in the host's speciation process is still in its infancy. In this study, we compared the intestinal microbiota among five sympatric pairs of dwarf (limnetic) and normal (benthic) lake whitefish Coregonus clupeaformis representing a continuum in the early stage of ecological speciation. We sequenced the 16s rRNA gene V3-V4 regions of the intestinal microbiota present in a total of 108 wild sympatric dwarf and normal whitefish as well as the water bacterial community from five lakes to (i) test for differences between the whitefish intestinal microbiota and the water bacterial community and (ii) test for parallelism in the intestinal microbiota of dwarf and normal whitefish...
March 14, 2018: Microbiome
Anne-Marie Garnerone, Fernando Sorroche, Lan Zou, Céline Mathieu-Demazière, Chang Fu Tian, Catherine Masson-Boivin, Jacques Batut
An ongoing signal exchange fine-tunes the symbiotic interaction between rhizobia and legumes, ensuring the establishment and maintenance of mutualism. In a recently identified regulatory loop, endosymbiotic S. meliloti exert a negative feedback on root infection in response to unknown plant cues. Upon signal perception, three bacterial Adenylate Cyclases (ACs) of the inner membrane, CyaD1, CyaD2 and CyaK, synthesize the second messenger cAMP that, together with the cAMP-dependent Clr transcriptional activator, activates the expression of genes involved in root infection control...
March 12, 2018: Journal of Bacteriology
Toby Spribille
The term symbiosis was first used in biology to describe the 'living together' of fungi and algae in lichens. For much of the 20th century, the fungal partner was assumed to be invested with the ability to produce the lichen body plan in presence of a photosynthesizing partner. However, studies of fungal evolution have uncovered discordance between lichen symbiotic outcomes and genome evolution of the fungus. At the same time, evidence has emerged that the structurally important lichen cortex contains lichen-specific, single-celled microbes, suggesting it may function like a biofilm...
March 9, 2018: Current Opinion in Plant Biology
Seung Ho Chung, Xiangfeng Jing, Yuan Luo, Angela E Douglas
The growth and reproduction of phloem sap-feeding insects requires the sustained function of intracellular bacteria localized in specialized cells known as bacteriocytes, giving the potential to target the bacterial symbiosis as a novel strategy for controlling sap-feeding insect pests. We focused on two genes in the pea aphid Acyrthosiphon pisum, amiD and ldcA1, which were acquired horizontally from bacteria and have the annotated function to degrade immunogenic bacterial peptidoglycan. We hypothesized that AmiD and LdcA1 function to eliminate peptidoglycan fragments released by the bacterial symbiont Buchnera inhabiting the bacteriocytes, thereby protecting the Buchnera from host attack...
March 8, 2018: Insect Biochemistry and Molecular Biology
Cindy J Castelle, Jillian F Banfield
The recent recovery of genomes for organisms from phyla with no isolated representative (candidate phyla) via cultivation-independent genomics enabled delineation of major new microbial lineages, namely the bacterial candidate phyla radiation (CPR), DPANN archaea, and Asgard archaea. CPR and DPANN organisms are inferred to be mostly symbionts, and some are episymbionts of other microbial community members. Asgard genomes encode typically eukaryotic systems, and their inclusion in phylogenetic analyses results in placement of eukaryotes as a branch within Archaea...
March 8, 2018: Cell
Juntra Wattanamethanont, Morakot Kaewthamasorn, Sonthaya Tiawsirisup
Ixodid ticks are important vectors of tick-borne disease agents affecting humans and animals, with wildlife often serving as important reservoirs. This study examined protozoal and bacterial infection in questing ticks in forest habitats in Chonburi Province, Thailand in 2015, using PCR and DNA sequencing techniques. A total of 12,184 ticks were morphologically identified to species and a subset of ticks were confirmed by PCR, targeting the tick mitochondrial 16S rRNA gene. Tick species collected included Haemaphysalis lagrangei (92...
March 5, 2018: Ticks and Tick-borne Diseases
Anna Michalik, Jacek Szwedo, Adam Stroiński, Dariusz Świerczewski, Teresa Szklarzewicz
In contrast to Cicadomorpha, in which numerous symbiotic bacteria have been identified and characterized, the symbionts of fulgoromorphans are poorly known. Here, we present the results of histological, ultrastructural, and molecular analyses of the symbiotic system of the planthopper Ommatidiotus dissimilis. Amplification, cloning, and sequencing of bacterial 16S RNA genes have revealed that O. dissimilis is host to five types of bacteria. Apart from bacteria Sulcia and Vidania, which are regarded as ancestral symbionts of Fulgoromorpha, three additional types of bacteria belonging to the genera Sodalis, Wolbachia, and Rickettsia have been detected...
March 7, 2018: Protoplasma
Sana Zouari, Monia Kamel Ben Halima, Mariana Reyes-Prieto, Amparo Latorre, Rosario Gil
Aphids (Hemiptera: Aphididae) can harbor two types of bacterial symbionts. In addition to the obligate endosymbiont Buchnera aphidicola Munson, Baumann and Kinsey 1991 (Enterobacteriales: Enterobacteriaceae), several facultative symbiotic bacteria, called secondary (S) symbionts, have been identified among many important pest aphid species. To determine interpopulational diversity of S-symbionts, we carried out a survey in a total of 18 populations of six aphid species collected from six localities in Tunisia, by performing a diagnostic polymerase chain reaction analysis of partial 16S-23S rRNA operon sequences...
February 28, 2018: Environmental Entomology
Lingui Xue, Hai Shang, Ping Ma, Xia Wang, Xiaoyan He, Junbo Niu, Juanli Wu
The aim was to study the effect of artificially constructed consortia of microalgae-bacterial symbionts on growth and lipid production by Chlorella vulgaris (C. vulgaris), as well as the inter-relationship between microalgae and bacterial in a photoautotrophic system. The results showed that compared to an axenic culture of C. vulgaris, H1 co-culture system (axenic C. vulgaris-Stenotrophomona smaltophilia) had the strongest effect on the C. vulgaris growth. The biomass, specific growth rate and maximum productivity of C...
February 28, 2018: Journal of Basic Microbiology
Irene Di Lecce, Chiara Bazzocchi, Jacopo G Cecere, Sara Epis, Davide Sassera, Barbara M Villani, Gaia Bazzi, Agata Negri, Nicola Saino, Fernando Spina, Claudio Bandi, Diego Rubolini
BACKGROUND: Ticks are obligate haematophagous ectoparasites of vertebrates and frequently parasitize avian species that can carry them across continents during their long-distance migrations. Ticks may have detrimental effects on the health state of their avian hosts, which can be either directly caused by blood-draining or mediated by microbial pathogens transmitted during the blood meal. Indeed, ticks host complex microbial communities, including bacterial pathogens and symbionts. Midichloria bacteria (Rickettsiales) are widespread tick endosymbionts that can be transmitted to vertebrate hosts during the tick bite, inducing an antibody response...
February 22, 2018: Parasites & Vectors
Kathleen M Morrow, Abbey Rose Tedford, M Sabrina Pankey, Michael P Lesser
Symbiotic associations with subcuticular bacteria (SCB) have been identified and studied in many echinoderms, including the SCB of the brooding brittle star, Amphipholis squamata. Previous studies on the SCB of A. squamata placed the isolated bacterium, designated as AS1, in the genus Vibrio (Gammaproteobacteria), but subsequent studies suggested that the SCB of echinoderms belong to the Alphaproteobacteria. This study examines the taxonomic composition of SCB associated with A. squamata from the Northwest Atlantic using the 16S rRNA gene and next generation sequencing (NGS)...
February 19, 2018: FEMS Microbiology Ecology
Joseph E Knelman, Emily B Graham, Janet S Prevéy, Michael S Robeson, Patrick Kelly, Eran Hood, Steve K Schmidt
Past research demonstrating the importance plant-microbe interactions as drivers of ecosystem succession has focused on how plants condition soil microbial communities, impacting subsequent plant performance and plant community assembly. These studies, however, largely treat microbial communities as a black box. In this study, we sought to examine how emblematic shifts from early successional Alnus viridus ssp. sinuata (Sitka alder) to late successional Picea sitchensis (Sitka spruce) in primary succession may be reflected in specific belowground changes in bacterial community structure and nitrogen cycling related to the interaction of these two plants...
2018: Frontiers in Microbiology
Kelly Brener-Raffalli, Camille Clerissi, Jeremie Vidal-Dupiol, Mehdi Adjeroud, François Bonhomme, Marine Pratlong, Didier Aurelle, Guillaume Mitta, Eve Toulza
BACKGROUND: Although the term holobiont has been popularized in corals with the advent of the hologenome theory of evolution, the underlying concepts are still a matter of debate. Indeed, the relative contribution of host and environment and especially thermal regime in shaping the microbial communities should be examined carefully to evaluate the potential role of symbionts for holobiont adaptation in the context of global changes. We used the sessile, long-lived, symbiotic and environmentally sensitive reef-building coral Pocillopora damicornis to address these issues...
February 20, 2018: Microbiome
Eman M Khalaf, Manish N Raizada
The cucurbit vegetables, including cucumbers, melons and pumpkins, have been cultivated for thousands of years without fungicides. However, their seed germination stage is prone to be infected by soil-borne fungal and oomycete pathogens. Endophytes are symbionts that reside inside plant tissues including seeds. Seed endophytes are founders of the juvenile plant microbiome and can promote host defense at seed germination and later stages. We previously isolated 169 bacterial endophytes associated with seeds of diverse cultivated cucurbits...
2018: Frontiers in Microbiology
Alexandra C Roder, S Patricia Stock
Steinernema nematodes and their Xenorhabdus partners form an obligate mutualistic association. This partnership is insecticidal to a wide range of insects. Steinernema rely on their Xenorhabdus partner to produce toxins inside the insect cadaver to liberate nutrients from the insect, as well as antimicrobials to sterilize the cadaver, thus creating a suitable environment for reproduction. In return, Steinernema vector their Xenorhabdus between insect hosts. Disruption of this partnership may affect the success of both partners...
February 16, 2018: Journal of Invertebrate Pathology
Marta Pinto-Carbó, Karl Gademann, Leo Eberl, Aurelien Carlier
Various plant species establish intimate symbioses with bacteria within their aerial organs. The bacteria are contained within nodules or glands often present in distinctive patterns on the leaves, and have been used as taxonomic marker since the early 20th century. These structures are present in very diverse taxa, including dicots (Rubiaceae and Primulaceae) and monocots (Dioscorea). The symbionts colonize the plants throughout their life cycles and contribute bioactive secondary metabolites to the association...
February 13, 2018: Current Opinion in Plant Biology
Germain Chevignon, Bret M Boyd, Jayce W Brandt, Kerry M Oliver, Michael R Strand
Many insects host facultative, bacterial symbionts that confer conditional fitness benefits to their hosts. Hamiltonella defensa is a common facultative symbiont of aphids that provides protection against parasitoid wasps. Protection levels vary among strains of H. defensa that are also differentially infected by bacteriophages named APSEs. However, little is known about trait variation among strains because only one isolate has been fully sequenced. Generating complete genomes for facultative symbionts is hindered by relatively large genome sizes but low abundances in hosts like aphids that are very small...
February 14, 2018: Genome Biology and Evolution
H Pieter J van Veelen, Joana Falcão Salles, B Irene Tieleman
The microbiome is essential for development, health and homeostasis throughout an animal's life. Yet, the origins and transmission processes governing animal microbiomes remain elusive for non-human vertebrates, oviparous vertebrates in particular. Eggs may function as transgenerational carriers of the maternal microbiome, warranting characterisation of egg microbiome assembly. Here, we investigated maternal and environmental contributions to avian eggshell microbiota in wild passerine birds: woodlark Lullula arborea and skylark Alauda arvensis...
February 14, 2018: ISME Journal
Marisa Skaljac, Phillipp Kirfel, Jens Grotmann, Andreas Vilcinskas
BACKGROUND: Aphids are agricultural pests that damage crops by direct feeding and by vectoring important plant viruses. Bacterial symbionts can influence aphid biology, e.g. by providing essential nutrients or facilitating adaptations to biotic and abiotic stress. RESULTS: We investigated the pea aphid (Acyrthosiphon pisum Harris) and its commonly associated secondary bacterial symbiont Serratia symbiotica to study the effect of this symbiont on host fitness and susceptibility to the insecticides imidacloprid, chlorpyrifos methyl, methomyl, cyantraniliprole and spirotetramat...
February 14, 2018: Pest Management Science
Maho Morita, Eric W Schmidt
Covering: up to 2018Symbiotic microbes interact with animals, often by producing natural products (specialized metabolites; secondary metabolites) that exert a biological role. A major goal is to determine which microbes produce biologically important compounds, a deceptively challenging task that often rests on correlative results, rather than hypothesis testing. Here, we examine the challenges and successes from the perspective of marine animal-bacterial mutualisms. These animals have historically provided a useful model because of their technical accessibility...
February 14, 2018: Natural Product Reports
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