A Marine Group A isolate relies on other growing bacteria for cell wall formation.

Most of Earth's prokaryotes live under energy limitation, yet the full breadth of strategies that enable survival under such conditions remain poorly understood. Here we report the isolation of a bacterial strain, IA91, belonging to the candidate phylum Marine Group A (SAR406 or 'Candidatus Marinimicrobia') that is unable to synthesize the central cell wall compound peptidoglycan itself. Using cultivation experiments and microscopy, we show that IA91 growth and cell shape depend on other bacteria, deriving peptidoglycan, energy and carbon from exogenous muropeptide cell wall fragments released from growing bacteria.

Identification and cultivation of anaerobic bacterial scavengers of dead cells.

The cycle of life and death and Earth's carbon cycle(s) are intimately linked, yet how bacterial cells, one of the largest pools of biomass on Earth, are recycled back into the carbon cycle remains enigmatic. In particular, no bacteria capable of scavenging dead cells in oxygen-depleted environments have been reported thus far. In this study, we discover the first anaerobes that scavenge dead cells and the two isolated strains use distinct strategies.

Subcellular Niche Segregation of Co-Obligate Symbionts in Whiteflies.

Many insects contain endosymbiotic bacteria within their bodies. In multiple endosymbiotic systems comprising two or more symbionts, each of the symbionts is generally localized in a different host cell or tissue. Bemisia tabaci (Sweet potato whitefly) possesses a unique endosymbiotic system where co-obligate symbionts are localized in the same bacteriocytes.

gen. nov., sp. nov., and gen. nov., sp. nov., novel lactate-producing bacteria isolated from mouse intestines, and an emended description of the family .

Two strictly anaerobic, Gram-stain-positive, non-motile bacteria (strains OPF53 and TOC12) were isolated from mouse intestines. Strains OPF53 and TOC12 grew at pH 5.5-9.

Complete Genome Sequence of sp. Strain TBR-22.

We report a complete genome sequence of a novel bacterial isolate, strain TBR-22, belonging to the class of the phylum , which was isolated from duckweed fronds. The genome expands our knowledge of the lifestyle of this abundant but rarely characterized phylum.

Draft Genome Sequence of Strain F-183.

Here, we report a draft genome sequence of a bacterial strain, F-183, isolated from a duckweed frond. Strain F-183 belongs to the family of the phylum , and its genomic information would contribute to understanding the ecophysiology of this abundant but rarely characterized phylum.

Host's guardian protein counters degenerative symbiont evolution.

Microbial symbioses significantly contribute to diverse organisms, where long-lasting associations tend to result in symbiont genome erosion, uncultivability, extinction, and replacement. How such inherently deteriorating symbiosis can be harnessed to stable partnership is of general evolutionary interest. Here, we report the discovery of a host protein essential for sustaining symbiosis.

Novel Plant-Associated Promotes Growth of Common Floating Aquatic Plants, Duckweeds.

Duckweeds are small, fast growing, and starch- and protein-rich aquatic plants expected to be a next generation energy crop and an excellent biomaterial for phytoremediation. Despite such an importance, very little is known about duckweed-microbe interactions that would be a key biological factor for efficient industrial utilization of duckweeds. Here we first report the duckweed growth promoting ability of bacterial strains belonging to the phylum , the members of which are known to inhabit soils and terrestrial plants, but their ecological roles and plant-microbe interactions remain largely unclear.

Environmental Acquisition of Gut Symbiotic Bacteria in the Saw-Toothed Stinkbug, (Hemiptera: Pentatomoidea: Dinidoridae).

Many plant-sucking stinkbugs possess a specialized symbiotic organ with numerous crypts in a posterior region of the midgut. In stinkbugs of the superfamily Pentatomoidea, specific γ-proteobacteria are hosted in the crypt cavities, which are vertically transmitted through host generations and essential for normal growth and survival of the host insects. Here we report the discovery of an exceptional gut symbiotic association in the saw-toothed stinkbug, (Hemiptera: Pentatomoidea: Dinidoridae), in which specific γ-proteobacterial symbionts are not transmitted vertically but acquired environmentally.

Isolation of a member of the candidate phylum 'Atribacteria' reveals a unique cell membrane structure.

A key feature that differentiates prokaryotic cells from eukaryotes is the absence of an intracellular membrane surrounding the chromosomal DNA. Here, we isolate a member of the ubiquitous, yet-to-be-cultivated phylum 'Candidatus Atribacteria' (also known as OP9) that has an intracytoplasmic membrane apparently surrounding the nucleoid. The isolate, RT761, is a subsurface-derived anaerobic bacterium that appears to have three lipid membrane-like layers, as shown by cryo-electron tomography.

Bacteriome-Associated Endosymbiotic Bacteria of Tree Sap Beetles (Coleoptera: Nosodendridae).

The family Nosodendridae is a small group of tree sap beetles with only 91 described species representing three genera from the world. In 1930s, bacteria-harboring symbiotic organs, called bacteriomes, were briefly described in a European species . Since then, however, no studies have been conducted on the nosodendrid endosymbiosis for decades.

Bacteriocytes and Endosymbionts of the German Cockroach , the Forest Cockroach , and Other Cockroach Species.

Cockroaches are commonly found in human residences and notorious as hygienic and nuisance pests. Notably, however, no more than 30 cockroach species are regarded as pests, while the majority of 4,500 cockroaches in the world are living in forest environments with little relevance to human life. Why some cockroaches have exceptionally adapted to anthropic environments and established pest status is of interest.

Host-symbiont specificity determined by microbe-microbe competition in an insect gut.

Despite the omnipresence of specific host-symbiont associations with acquisition of the microbial symbiont from the environment, little is known about how the specificity of the interaction evolved and is maintained. The bean bug acquires a specific bacterial symbiont of the genus from environmental soil and harbors it in midgut crypts. The genus consists of over 100 species, showing ecologically diverse lifestyles, and including serious human pathogens, plant pathogens, and nodule-forming plant mutualists, as well as insect mutualists.

Comparative cytology, physiology and transcriptomics of Burkholderia insecticola in symbiosis with the bean bug Riptortus pedestris and in culture.

In the symbiosis of the bean bug Riptortus pedestris with Burkholderia insecticola, the bacteria occupy an exclusive niche in the insect midgut and favor insect development and reproduction. In order to understand how the symbiotic bacteria stably colonize the midgut crypts and which services they provide to the host, we compared the cytology, physiology, and transcriptomics of free-living and midgut-colonizing B. insecticola.

Recurrent symbiont recruitment from fungal parasites in cicadas.

Diverse insects are associated with ancient bacterial symbionts, whose genomes have often suffered drastic reduction and degeneration. In extreme cases, such symbiont genomes seem almost unable to sustain the basic cellular functioning, which comprises an open question in the evolution of symbiosis. Here, we report an insect group wherein an ancient symbiont lineage suffering massive genome erosion has experienced recurrent extinction and replacement by host-associated pathogenic microbes.

Burkholderia insecticola sp. nov., a gut symbiotic bacterium of the bean bug Riptortus pedestris.

A Gram-negative, aerobic, rod-shaped, non-spore-forming, motile bacterium, designated strain RPE64, was isolated from the gut symbiotic organ of the bean bug Riptortus pedestris, collected in Tsukuba, Japan, in 2007. 16S rRNA gene sequencing showed that this strain belongs to the Burkholderia glathei clade, exhibiting the highest sequence similarity to Burkholderia peredens LMG 29314 (100 %), Burkholderia turbans LMG 29316 (99.52 %) and Burkholderia ptereochthonis LMG 29326 (99.

Fusimonas intestini gen. nov., sp. nov., a novel intestinal bacterium of the family Lachnospiraceae associated with diabetes in mice.

Our previous study shows that an anaerobic intestinal bacterium strain AJ110941 contributes to type 2 diabetes development in mice. Here we phylogenetically and physiologically characterized this unique mouse gut bacterium. The 16S rRNA gene analysis revealed that the strain belongs to the family Lachnospiraceae but shows low sequence similarities ( < 92.

A Novel, Extremely Elongated, and Endocellular Bacterial Symbiont Supports Cuticle Formation of a Grain Pest Beetle.

The saw-toothed grain beetle, (Silvanidae), is a cosmopolitan stored-product pest. Early studies on in the 1930s described the presence of peculiar bacteriomes harboring endosymbiotic bacteria in the abdomen. Since then, however, the microbiological nature of the symbiont has been elusive.

Small genome symbiont underlies cuticle hardness in beetles.

Beetles, representing the majority of the insect species diversity, are characterized by thick and hard cuticle, which plays important roles for their environmental adaptation and underpins their inordinate diversity and prosperity. Here, we report a bacterial endosymbiont extremely specialized for sustaining beetle's cuticle formation. Many weevils are associated with a γ-proteobacterial endosymbiont lineage , whose evolutionary origin is estimated as older than 100 million years, but its functional aspect has been elusive.

Novel bacteriocyte-associated pleomorphic symbiont of the grain pest beetle (Coleoptera: Bostrichidae).

Background: The lesser grain borer (Coleoptera: Bostrichidae) is a stored-product pest beetle. Early histological studies dating back to 1930s have reported that and other bostrichid species possess a pair of oval symbiotic organs, called the bacteriomes, in which the cytoplasm is densely populated by pleomorphic symbiotic bacteria of peculiar rosette-like shape. However, the microbiological nature of the symbiont has remained elusive.

A Novel Symbiotic Ciliate (Ciliophora: Peritrichia) in the Hindgut of a Stag Beetle (Coleoptera: Lucanidae).

Bell-shaped ciliates of the subclass Peritrichia, such as Vorticella, Carchesium and Epistylis, are commonly found in freshwater and other aquatic environments, either solitary or colonial. Peritrichs attach to a substratum via a contractile or non-motile stalk, and collect food particles by water current using ciliary rows around the edge of the bell, called the peristome. Some peritrichs are epibiotic and ectocommensalistic associates of aquatic insects and other animals, settling on the surface of their specific hosts.

Lentimicrobium saccharophilum gen. nov., sp. nov., a strictly anaerobic bacterium representing a new family in the phylum Bacteroidetes, and proposal of Lentimicrobiaceae fam. nov.

A novel, strictly anaerobic, short rod-shaped bacterium, designated strain TBC1, was isolated from methanogenic granular sludge in a full-scale mesophilic upflow anaerobic sludge blanket reactor treating high-strength starch-based organic wastewater. Cells of this strain were 2-4 µm long and 0.4-0.