An MRI time course of 512 echo-planar images (EPI) in resting human brain obtained every 250 ms reveals fluctuations in signal intensity in each pixel that have a physiologic origin. Regions of the sensorimotor cortex that were activated secondary to hand movement were identified using functional MRI methodology (FMRI). Time courses of low frequency (< 0.1 Hz) fluctuations in resting brain were observed to have a high degree of temporal correlation (P < 10(-3)) within these regions and also with time courses in several other regions that can be associated with motor function. It is concluded that correlation of low frequency fluctuations, which may arise from fluctuations in blood oxygenation or flow, is a manifestation of functional connectivity of the brain.

Functional connectivity in the motor cortex of resting human brain using echo-planar MRI.

Evolution of Protein Molecules

Gram-negative bacteria characteristically are surrounded by an additional membrane layer, the outer membrane. Although outer membrane components often play important roles in the interaction of symbiotic or pathogenic bacteria with their host organisms, the major role of this membrane must usually be to serve as a permeability barrier to prevent the entry of noxious compounds and at the same time to allow the influx of nutrient molecules. This review summarizes the development in the field since our previous review (H. Nikaido and M. Vaara, Microbiol. Rev. 49:1-32, 1985) was published. With the discovery of protein channels, structural knowledge enables us to understand in molecular detail how porins, specific channels, TonB-linked receptors, and other proteins function. We are now beginning to see how the export of large proteins occurs across the outer membrane. With our knowledge of the lipopolysaccharide-phospholipid asymmetric bilayer of the outer membrane, we are finally beginning to understand how this bilayer can retard the entry of lipophilic compounds, owing to our increasing knowledge about the chemistry of lipopolysaccharide from diverse organisms and the way in which lipopolysaccharide structure is modified by environmental conditions.

Molecular Basis of Bacterial Outer Membrane Permeability Revisited

Salinity is a major factor controlling the distribution of biota in aquatic systems, and most aquatic multicellular organisms are either adapted to life in saltwater or freshwater conditions. Consequently, the saltwater–freshwater mixing zones in coastal or estuarine areas are characterized by limited faunal and floral diversity. Although changes in diversity and decline in species richness in brackish waters is well documented in aquatic ecology, it is unknown to what extent this applies to bacterial communities. Here, we report a first detailed bacterial inventory from vertical profiles of 60 sampling stations distributed along the salinity gradient of the Baltic Sea, one of world's largest brackish water environments, generated using 454 pyrosequencing of partial (400 bp) 16S rRNA genes. Within the salinity gradient, bacterial community composition altered at broad and finer-scale phylogenetic levels. Analogous to faunal communities within brackish conditions, we identified a bacterial brackish water community comprising a diverse combination of freshwater and marine groups, along with populations unique to this environment. As water residence times in the Baltic Sea exceed 3 years, the observed bacterial community cannot be the result of mixing of fresh water and saltwater, but our study represents the first detailed description of an autochthonous brackish microbiome. In contrast to the decline in the diversity of multicellular organisms, reduced bacterial diversity at brackish conditions could not be established. It is possible that the rapid adaptation rate of bacteria has enabled a variety of lineages to fill what for higher organisms remains a challenging and relatively unoccupied ecological niche.

/pdf/transitions-in-bacterial-communities-along-the-2000-km-2cszg1uinl.pdf

Transitions in bacterial communities along the 2000 km salinity gradient of the Baltic Sea

Plants depend upon beneficial interactions between roots and microbes for nutrient availability, growth promotion, and disease suppression. High-throughput sequencing approaches have provided recent insights into root microbiomes, but our current understanding is still limited relative to animal microbiomes. Here we present a detailed characterization of the root-associated microbiomes of the crop plant rice by deep sequencing, using plants grown under controlled conditions as well as field cultivation at multiple sites. The spatial resolution of the study distinguished three root-associated compartments, the endosphere (root interior), rhizoplane (root surface), and rhizosphere (soil close to the root surface), each of which was found to harbor a distinct microbiome. Under controlled greenhouse conditions, microbiome composition varied with soil source and genotype. In field conditions, geographical location and cultivation practice, namely organic vs. conventional, were factors contributing to microbiome variation. Rice cultivation is a major source of global methane emissions, and methanogenic archaea could be detected in all spatial compartments of field-grown rice. The depth and scale of this study were used to build coabundance networks that revealed potential microbial consortia, some of which were involved in methane cycling. Dynamic changes observed during microbiome acquisition, as well as steady-state compositions of spatial compartments, support a multistep model for root microbiome assembly from soil wherein the rhizoplane plays a selective gating role. Similarities in the distribution of phyla in the root microbiomes of rice and other plants suggest that conclusions derived from this study might be generally applicable to land plants.

https://www.pnas.org/content/pnas/112/8/E911.full.pdf

Structure, variation, and assembly of the root-associated microbiomes of rice.

The taxonomic positions of Flavobacterium sp. strain IF

Proposal of Two New Species in the Genus Microbacterium dextranolyticum sp. Microbacterium

/pdf/compound-producing-actinomycete-isolated-from-thai-cave-soil-1wpqwgk3zp.pdf

compound-producing actinomycete isolated from Thai cave soil and

Taxonomic significance of morphological and chemotaxonomic characteristics and phylogeny in Gram-positive bacteria

Abstract. Rachmania MK, Ningsih F, Sari DCAF, Eshananda Y, Sakai Y, Yabe S, Yokota A, Sjamsuridzal W. 2022. Identification and screening of enzymatic abilities of Ktedonobacteria from forest soil of Cisolok Geothermal Area, Indonesia. Biodiversitas 23: 4686-4695. This study aimed to provide information on culturable Ktedonobacteria from forest soil in the Cisolok geothermal area and their potential as enzyme producers. Twelve ktedonobacterial isolates were obtained from this study and identified based on full-sequence of the 16S rRNA gene. Seventeen isolates (including five isolates from previous studies) were used for enzymatic screening and phylogenetic analyses. Screening of amylolytic (0.5% soluble starch) and cellulolytic (0.5% carboxymethylcellulose) (CMC) activities from ktedonobacterial isolates was performed on a ten-fold diluted R2A agar medium, and were incubated at 30 °C for 21 days. The EzBioCloud search revealed that all isolates showed low sequence similarities with Dictyobacter aurantiacus S-27T (97.82 to 98.18%) as their closest related species. The phylogenetic tree showed that all isolates belong to the genus Dictyobacter (family Dictyobacteraceae of the class Ktedonobacteria). All isolates formed a monophyletic group and were placed as the sister clade to D. aurantiacus, as supported by a very strong bootstrap value (99%). Screening of amylolytic and cellulolytic abilities showed that most isolates (88.23%) were able to degrade both 0.5% starch and 0.5% CMC as substrates. This study revealed the presence of Ktedonobacteria with amylolytic and cellulolytic abilities in the forest soil of Cisolok geothermal area.

Identification and screening of enzymatic abilities of Ktedonobacteria from forest soil of Cisolok Geothermal Area, Indonesia

During the course of isolation of actinomycetes from soil in screening programs for pharmacologically active compounds, actinomycete strain AL-50780T (T = type strain), which had unusual morphological characteristics, was isolated from a soil sample collected in Bangkok, Thailand, and its taxonomic status was studied. This isolate formed unique coralloid sporophores on substrate mycelia and rarely formed coremia on solid media. Moreover, this isolate has the following novel chemotaxonomic characteristics: the cell wall type is type I11 (meso-2,6-diaminopimelic acid, meso-diaminopimelic acid, and no glycine), the whole-cell sugar pattern type is type C (no diagnostic sugars), and the fatty acid type is type la. The genera that have type III/C cell walls are Brevibacterium, Geodermatophilus, Actinosynnema , Microtetraspora , Nocardiopsis, Saccharothrix, Streptoalloteichus, Thermomonospora, and Thermoactinomyces. However, the characteristics of these genera are not consistent with the strain AL-50780T morphological or chemotaxonomic characteristics (5). The genera that have fatty acid type la are Actinomyces (cell wall types V and VI), Arcanobacterium (cell wall type VI), Dermatophilus (cell wall type III/B), Corynebacterium (cell wall type IV/A), and Intrasporangium (cell wall type I). The characteristics of these genera also are not consistent with strain AL-50780T cell wall type and morphological characteristics (5). We propose that strain AL-50780T should be included in a new genus, Actinocorallia. Strain IF0 15485 (= AL-50780) is the type strain of the type species, Actinocorallia herbida. In addition, this strain produces an azaserine-like antibiotic.

Actinocovallia gen. nov., a New Genus of the

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