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Nocardioides , a genus belonging to Actinomycetes , can endure various low-nutrient conditions. It can degrade pollutants using multiple organic materials such as carbon and nitrogen sources. The characteristics and applications of Nocardioides are described in detail in this review, with emphasis on the degradation of several hard-to-degrade pollutants by using Nocardioides , including aromatic compounds, hydrocarbons, haloalkanes, nitrogen heterocycles, and polymeric polyesters. Nocardioides has unique advantages when it comes to hard-to-degrade pollutants. Compared to other strains, Nocardioides has a significantly higher degradation rate and requires less time to break down substances. This review can be a theoretical basis for developing Nocardioides as a microbial agent with significant commercial and application potential.

A novel actinomycete, strain 1_25 T , was isolated from soil under a black Gobi rock sample from Shuangta, PR China, and characterized using a polyphasic taxonomic approach. The results of comparative analysis of the 16S rRNA gene sequences indicated the 1_25 T represented a member of the genus Streptomyces . Chemotaxonomic data revealed that 1_25 T possessed MK-9(H 8 ) as the major menaquinone. The cell wall contained ll-diaminopimelic acid (ll-DAP) and the whole-cell sugar pattern consisted of ribose, glucose and galactose. Major fatty acid methyl esters were observed to be iso-C 16 : 0 (23.6 %), and anteiso-C 15 : 0 (10.4 %). The genomic DNA G+C content of 1_25 T was 69 mol %. The results of phylogenetic analysis based on 16S rRNA gene sequence indicated that 1_25 T had high sequence similarity with Streptomyces qinglanensis 172205 T (98.1 %), Streptomyces lycii TRM 66187 T (98 %), and Streptomyces griseocarneus JCM4580 T (98 %). In addition to the differences in phenotypic characters, the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between 1_25 T and closely related species were below the recommended threshold values for assigning strains to the same species. The fermentation product of 1_25 T in ISP2 had an inhibitory effect on Staphylococcus aureus . On the basis of these genotypic and phenotypic characteristics, strain 1_25 T (=JCM 34936 T =GDMCC 4.216 T ) represents a novel species of the genus Streptomyces , for which the name Streptomyces gobiensis sp. nov. is proposed.

Simple Summary: Adaptative extremophiles are frequently found in various glacial ecological niches, such as glacial meltwater, ice, snow, and permafrost. However, no systematic study has investigated the diverse and temporary survival of culturable bacteria in newly exposed moraines around glacier snouts. The findings of this study revealed the diversity of culturable heterotrophic bacteria in a newly exposed moraine and demonstrated the evolution, competition, and selective growth of bacteria facing primary succession. This study not only helps to understand the high diversity of culturable bacteria in the newly exposed moraine at a glacier snout but also provides a theoretical basis for the study of microbial resources surviving in the transition region between glaciers and retreats. Laohugou Glacier No. 12 is located on the northern slope of the western Qilian Mountains with a temperate continental wet climate and an extremely cold winter. Bacteria in a newly exposed moraine have to cope with various pressures owing to deglaciation at the glacier snout. However, limited information is available regarding the high diversity and temporary survival of culturable heterotrophic bacteria under various environmental stresses. To examine the tolerance of extremophiles against varying environmental conditions in a newly exposed moraine, we simulated environmental stress in bacterial cultures. The results showed that the isolated strains belonged to actinobacteria, Proteobacteria, Bacteroidetes, Deinococcus-Thermus, and Firmicutes. Actinobacteria was the most abundant phylum, followed by Proteobacteria, at both high and low temperatures. Pseudarthrobacter was the most abundant genus, accounting for 14.2% of the total isolates. Although several microorganisms grew at 10 °C, the proportion of microorganisms that grew at 25 °C was substantially higher. In particular, 50% of all bacterial isolates grew only at a high temperature (HT), whereas 21.4% of the isolates grew at a low temperature (LT), and 38.6% of the isolates grew at both HT and LT. In addition, many radiation-resistant extremophiles were identified, which adapted to both cold and oxidative conditions. The nearest neighbors of approximately >90% of bacteria belonged to a nonglacial environment, such as oil-contaminated soil, rocks, and black sand, instead of glacial niches. This study provides insights into the ecological traits, stress responses, and temporary survival of culturable heterotrophic bacteria in a newly exposed moraine with variable environmental conditions and the relationship of these communities with the non-glacial environment. This study may help to understand the evolution, competition, and selective growth of bacteria in the transition regions between glaciers and retreats in the context of glacier melting and retreat owing to global warming. [ABSTRACT FROM AUTHOR]

The dissacharide trehalose is an important intracellular osmoprotectant and the OtsA/B pathway is the principal pathway for trehalose biosynthesis in a wide range of bacterial species. Scaffolding proteins and other cytoskeletal elements play an essential role in morphogenetic processes in bacteria. Here we describe how OtsA, in addition to its role in trehalose biosynthesis, functions as an osmotic stress sensor to regulate cell morphology in Arthrobacter strain A3. In response to osmotic stress, this and other Arthrobacter species undergo a transition from bacillary to myceloid growth. An otsA null mutant exhibits constitutive myceloid growth. Osmotic stress leads to a depletion of trehalose-6-phosphate, the product of the OtsA enzyme, and experimental depletion of this metabolite also leads to constitutive myceloid growth independent of OtsA function. In vitro analyses indicate that OtsA can self-assemble into protein networks, promoted by trehalose-6-phosphate, a property that is not shared by the equivalent enzyme from E. coli, despite the latter’s enzymatic activity when expressed in Arthrobacter. This, and the localization of the protein in non-stressed cells at the mid-cell and poles, indicates that OtsA from Arthrobacter likely functions as a cytoskeletal element regulating cell morphology. Recruiting a biosynthetic enzyme for this morphogenetic function represents an intriguing adaptation in bacteria that can survive in extreme environments. [ABSTRACT FROM AUTHOR]

In this study, a culture-independent Illumina MiSeq sequencing strategy was applied to investigate the microbial communities colonizing the ancient painted sculptures of the Maijishan Grottoes, a famous World Cultural Heritage site listed by UNESCO in China. Four mixed samples were collected from Cave 4–4 of the Maijishan Grottoes, the so-called Upper Seven Buddha Pavilion, which was built during the Northern Zhou Dynasty (557-581AD). The 16/18S rRNA gene-based sequences revealed a rich bacterial diversity and a relatively low fungal abundance, including the bacterial groups Actinobacteria, Acidobacteria, Bacteroidetes, Cyanobacteria, Chloroflexi, Firmicutes, Proteobacteria and Verrucomicrobia and the fungal groups Ascomycota, Basidiomycota and Chytridiomycota. Among them, the bacteria genera of Pseudonocardia and Rubrobacter and unclassified fungi in the order of Capnodiales were dominant. The relative abundance of Pseudonocardia in the painted layer samples was higher than that in the dust sample, while Cyanobacteria dominated in the dust sample. Many of them have been discovered at other cultural heritage sites and associated with the biodeterioration of cultural relics. The presence and activity of these pioneering microorganisms may lead to an unexpected deterioration of the painted sculptures that are preserved in this heritage site. Thus, proper management strategies and potential risk monitoring should be used in the Maijishan Grottoes to improve the conservation of these precious painted sculptures. [ABSTRACT FROM AUTHOR]

Permafrost degradation affects soil properties and vegetation, but little is known about its consequent effects on the soil bacterial community. In this study, we analyzed the bacterial community structure of 12 permafrost-affected soil samples from four principal permafrost types, sub-stable permafrost (SSP), transition permafrost (TP), unstable permafrost (UP) and extremely unstable permafrost (EUP), to investigate the effects of vegetation characteristics and soil properties on bacterial community structure during the process of permafrost degradation. Proteobacteria, Acidobacteria, Actinobacteria and Bacteroidetes were the predominant phyla in all four permafrost soil types. The relative abundance of Proteobacteria decreased in the order SSP > TP> UP > EUP, whereas the abundance of Actinobacteria increased in the order SSP < TP < UP < EUP. Moreover, the Actinobacteria/Proteobacteria ratio increased significantly in the order SSP < TP < UP < EUP along with permafrost degradation, which may be useful as a sign of permafrost degradation. Redundancy analysis (RDA) showed that bacterial communities could be clustered by permafrost types. Analysis of single factors revealed that soil moisture (SM) was the most important factor affecting the bacterial community structure and diversity, followed by soil total nitrogen (STN) and vegetation cover (VC). Partial RDA analysis showed that the soil properties and vegetation characteristics jointly shaped the bacterial community structure. Hence, we can conclude that permafrost degradation, caused by global warming, affects vegetation and soil properties and consequently drives changes in the soil bacterial community structure. [ABSTRACT FROM PUBLISHER]

The aim of this study was to survey the response of the microbial community to crude oil and the diversity of alkane hydroxylase ( alkB) genes in soil samples from the Qinghai-Tibet Plateau (QTP). The enrichment cultures and clone libraries were used. Finally, 53 isolates and 94 alkB sequences were obtained from 10 pristine soil samples after enrichment at 10 °C with crude oil as sole carbon source. The isolates fell into the phyla Proteobacteria, Actinobacteria, and Bacteroidetes, with the dominance of Pseudomonas and Acinetobacter. The composition of degraders was different from polar habitats where Acinetobacter sp. is not a predominant responder of alkane degradative microbial communities. Phylogenetic analysis showed that the alkB genes from isolates and enrichment communities formed eight clusters and mainly related with alkB genes of Pseudomonas, Rhodococcus, and Acinetobacter. The alkB gene diversity in the QTP was lower than marine environments and polar soil samples. In particular, a total of 10 isolates exhibiting vigorous growth with crude oil could detect no crude oil degradation-related gene sequences, such as alkB, P450, almA, ndoB, and xylE genes. The Shannon-Wiener index of the alkB clone libraries from the QTP ranged from 1.00 to 2.24 which is similar with polar pristine soil samples but lower than that of contaminated soils. These results indicated that the Pseudomonas, Acinetobacter, and Rhodococcus genera are the candidate for in situ bioremediation, and the environment of QTP may be still relatively uncontaminated by crude oil. [ABSTRACT FROM AUTHOR]

Actinobacteria are typically soil bacteria that have important roles in soil development and biogeochemical cycling. However, little is known about the occurrence or the succession of communities of Actinobacteria in new habitats. In this study, we investigated the diversity and succession of the actinobacterial communities that inhabited the forelands of the Tianshan Glacier (China), which ranged in successional age from 0 to 100 years since the forefield was deglaciated. Actinobacteria was one of the dominant phyla in the glacier foreland and included the orders Acidimicrobiales, Actinomycetales, Rubrobacteriales and Solirubrobacteriales. Actinomycetales was the dominant order, but its relative abundance decreased through the chronosequence. Acidimicrobiales and Solirubrobacteriales were more abundant in the late stages of succession than in the early ones. The abundance of Rubrobacteriales was only high at 74a. The dominant genera Nocardioides and Arthrobacter were widely distributed and were found in each stage of succession. With nonparametric and rarefaction estimated analyses, we found that the phylotype richness of Actinobacteria was significantly correlated with time (r = 0.886, p = 0.019). The succession of actinobacterial communities was divided into 3 stages: the early stage (6a), the intermediate stage (10a and 20a) and the late stage (60a, 74a, and 100a). Based on the canonical correspondence analysis, the actinobacterial communities were affected significantly by soil pH (r = -0.834, p = 0.039) and somewhat by the C/N ratio (r = 0.783, p = 0.066). The nonmetric multidimensional scaling analysis showed that the effect of geographical isolation on the actinobacterial communities was greater than that of the soils in the development of the chronosequence. [ABSTRACT FROM AUTHOR]

Tiantishan Grottoes, a famous site well known for its historical status in the spread of Buddhism art in ancient China, were selected for a comparison and analysis of microbial taxonomic characteristics on the wall paintings under different preservation conditions: in situ and ex situ conservation. A total of 12 samples were collected from three different cave wall paintings preserved in situ or ex situ . The 16/18S rRNA gene-based sequences revealed a high bacterial diversity and a relative low fungal abundance, including bacterial groups Firmicutes, Actinobacteria, Proteobacteria, Bacteroidetes, Cyanobacteria, Acidobacteria, Deinococcus-Thermus and Fusobacteria; and fungal groups Ascomycota and Basidiomycota. Among them, two bacterial genera of the Promicromonospora and Planomicrobium and fungal order of the Sordariales and the family of Trichocomaceae were dominant in the samples preserved ex situ . Some of them have been reported at other cultural heritage sites and associated with the biodeterioration of cultural relics. The over-growth of these microbes led to the abundant filaments formed visible on the surface of the ex situ wall paintings, which preserved under museum conditions. Application of preservation materials including animal glue and wet gypsum to take them off from grottoes and strengthen, and subsequent long-term preservation under poor conditions in museums were mainly responsible for the microbial outbreaks. To avoid similar problems in the future, reasonable intervention measures and strict micro-environmental control must be implemented to the ex situ preservation of wall paintings. Our results have profound significance for clarify the occurrence of microbial invasions and mechanisms on the wall paintings; it is helpful to development a reasonable artificial intervention measures for conservation work of the wall paintings in the future. [ABSTRACT FROM AUTHOR]