Cryosphere: a frozen home of microbes and a potential source for drug discovery.

The world is concerned about the emergence of pathogens and the occurrence and spread of antibiotic resistance among pathogens. Drug development requires time to combat these issues. Consequently, drug development from natural sources is unavoidable. Cryosphere represents a gigantic source of microbes that could be the bioprospecting source of natural products with unique scaffolds as molecules or drug templates. This review focuses on the novel source of drug discovery and cryospheric environments as a potential source for microbial metabolites having potential medicinal applications. Furthermore, the problems encountered in discovering metabolites from cold-adapted microbes and their resolutions are discussed. By adopting modern practical approaches, the discovery of bioactive compounds might fulfill the demand for new drug development.

Bacteria populating freshly appeared supraglacial lake possess metals and antibiotic-resistant genes.

Antibiotic resistance (AR) has been extensively studied in natural habitats and clinical applications. AR is mainly reported with the use and misuse of antibiotics; however, little is known about its presence in antibiotic-free remote supraglacial lake environments. This study evaluated bacterial strains isolated from supraglacial lake debris and meltwater in Dook Pal Glacier, northern Pakistan, for antibiotic-resistant genes (ARGs) and metal-tolerant genes (MTGs) using conventional PCR. Several distinct ARGs were reported in the bacterial strains isolated from lake debris (92.5%) and meltwater (100%). In lake debris, 57.5% of isolates harbored the blaTEM gene, whereas 58.3% of isolates in meltwater possessed blaTEM and qnrA each. Among the ARGs, qnrA was dominant in debris isolates (19%), whereas in meltwater isolates, qnrA (15.2%) and blaTEM (15.2%) were dominant. ARGs were widely distributed among the bacterial isolates and different bacteria shared similar types of ARGs. Relatively greater number of ARGs were reported in Gram-negative bacterial strains. In addition, 92.5% of bacterial isolates from lake debris and 83.3% of isolates from meltwater harbored MTGs. Gene copA was dominant in meltwater isolates (50%), whereas czcA was greater in debris bacterial isolates (45%). Among the MTGs, czcA (18.75%) was dominant in debris strains, whereas copA (26.0%) was greater in meltwater isolates. This presents the co-occurrence and co-selection of MTGs and ARGs in a freshly appeared supraglacial lake. The same ARGs and MTGs were present in different bacteria, exhibiting horizontal gene transfer (HGT). Both positive and negative correlations were determined between ARGs and MTGs. The research provides insights into the existence of MTGs and ARGs in bacterial strains isolated from remote supraglacial lake environments, signifying the need for a more detailed study of bacteria harboring ARGs and MTGs in supraglacial lakes.

Patterns of bacterial communities in the rhizosphere and rhizoplane of alpine wet meadows.

Wet meadows, a type of wetland, are vulnerable to climate change and human activity, impacting soil properties and microorganisms that are crucial to the ecosystem processes of wet meadows. To decipher the ecological mechanisms and processes involved in wet meadows, it is necessary to examine the bacterial communities associated with plant roots. To gain valuable insight into the microbial dynamics of alpine wet meadows, we used Illumina MiSeq sequencing to investigate how environmental factors shape the bacterial communities thriving in the rhizosphere and rhizoplane of three plant species: Cremanthodium ellisii, Caltha scaposa, and Cremanthodium lineare. The most abundant bacterial phyla in rhizosphere and rhizoplane were Proteobacteria > Firmicutes > Actinobacteria, while Macrococcus, Lactococcus, and Exiguobacterium were the most abundant bacterial genera between rhizosphere and rhizoplane. The mantel test, network, and structure equation models revealed that bacterial communities of rhizosphere were shaped by total nitrogen (TN), soil water content (SWC), soil organic carbon (SOC), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), pH, however, rhizoplane bacterial communities exhibited varying results. The bacterial communities exhibited significant heterogeneity, with stochastic process predominating in both the rhizosphere and rhizoplane. PICRUSt2 and FAPROTAX analysis revealed substantial differences in key biogeochemical cycles and metabolic functional predictions. It was concluded that root compartments significantly influenced the bacterial communities, although plant species and elevation asserted varying effects. This study portrays how physicochemical properties, plant species, and elevations can shift the overall structure and functional repertoire of bacterial communities in alpine wet meadows.

Temperature-dependent transformation of microbial community: A systematic approach to analyzing functional microbes and biogas production.

The stability and effectiveness of the anaerobic digestion (AD) system are significantly influenced by temperature. While majority research has focused on the composition of the microbial community in the AD process, the relationships between functional gene profile deduced from gene expression at different temperatures have received less attention. The current study investigates the AD process of potato peel waste and explores the association between biogas production and microbial gene expression at 15, 25, and 35 °C through metatranscriptomic analysis. The production of total biogas decreased with temperature at 15 °C (19.94 mL/g VS), however, it increased at 35 °C (269.50 mL/g VS). The relative abundance of Petrimonas, Clostridium, Aminobacterium, Methanobacterium, Methanothrix, and Methanosarcina were most dominant in the AD system at different temperatures. At the functional pathways level 3, α-diversity indices, including Evenness (Y = 5.85x + 8.85; R2 = 0.56), Simpson (Y = 2.20x + 2.09; R2 = 0.33), and Shannon index (Y = 1.11x + 4.64; R2 = 0.59), revealed a linear and negative correlation with biogas production. Based on KEGG level 3, several dominant functional pathways associated with Oxidative phosphorylation (ko00190) (25.09, 24.25, 24.04%), methane metabolism (ko00680) (30.58, 32.13, and 32.89%), and Carbon fixation pathways in prokaryotes (ko00720) (27.07, 26.47, and 26.29%), were identified at 15 °C, 25 °C and 35 °C. The regulation of biogas production by temperature possibly occurs through enhancement of central function pathways while decreasing the diversity of functional pathways. Therefore, the methanogenesis and associated processes received the majority of cellular resources and activities, thereby improving the effectiveness of substrate conversion to biogas. The findings of this study illustrated the crucial role of central function pathways in the effective functioning of these systems.

Evaluating the relative influence of climate and human activities on recent vegetation dynamics in West Bengal, India.

Assessing the relative importance of climate change and human activities is important in developing sustainable management policies for regional land use. In this study, multiple remote sensing datasets, i.e. CHIRPS (Climate Hazard Group InfraRed Precipitation with Station Data) precipitation, MODIS Land Surface Temperature (LST), Enhanced Vegetation Index (EVI), Potential Evapotranspiration (PET), Soil Moisture (SM), WorldPop, and nighttime light have been analyzed to investigate the effect that climate change (CC) and regional human activities (HA) have on vegetation dynamics in eastern India for the period 2000 to 2022. The relative influence of climate and anthropogenic factors is evaluated on the basis of non-parametric statistics i.e., Mann-Kendall and Sen's slope estimator. Significant spatial and elevation-dependent variations in precipitation and LST are evident. Areas at higher elevations exhibit increased mean annual temperatures (0.22 °C/year, p < 0.05) and reduced winter precipitation over the last two decades, while the northern and southwest parts of West Bengal witnessed increased mean annual precipitation (17.3 mm/year, p < 0.05) and a slight cooling trend. Temperature and precipitation trends are shown to collectively impact EVI distribution. While there is a negative spatial correlation between LST and EVI, the relationship between precipitation and EVI is positive and stronger (R2 = 0.83, p < 0.05). Associated hydroclimatic parameters are potent drivers of EVI, whereby PET in the southwestern regions leads to markedly lower SM. The relative importance of CC and HA on EVI also varies spatially. Near the major conurbation of Kolkata, and confirmed by nighttime light and population density data, changes in vegetation cover are very clearly dominated by HA (87%). In contrast, CC emerges as the dominant driver of EVI (70-85%) in the higher elevation northern regions of the state but also in the southeast. Our findings inform policy regarding the future sustainability of vulnerable socio-hydroclimatic systems across the entire state.

Agricultural Waste Management by Production of Second-Generation Bioethanol from Sugarcane Bagasse Using Indigenous Yeast Strain.

In the wake of rapid industrialization and burgeoning transportation networks, the escalating demand for fossil fuels has accelerated the depletion of finite energy reservoirs, necessitating urgent exploration of sustainable alternatives. To address this, current research is focusing on renewable fuels like second-generation bioethanol from agricultural waste such as sugarcane bagasse. This approach not only circumvents the contentious issue of food-fuel conflicts associated with biofuels but also tackles agricultural waste management. In the present study indigenous yeast strain, Clavispora lusitaniae QG1 (MN592676), was isolated from rotten grapes to ferment xylose sugars present in the hemicellulose content of sugarcane bagasse. To liberate the xylose sugars, dilute acid pretreatment was performed. The highest reducing sugars yield was 1.2% obtained at a temperature of 121 °C for 15 min, a solid-to-liquid ratio of 1:25 (% w/v), and an acid concentration of 1% dilute acid H2SO4 that was significantly higher (P < 0.001) yield obtained under similar conditions at 100 °C for 1 h. The isolated strain was statistically optimized for fermentation process by Plackett-Burman design to achieve the highest ethanol yield. Liberated xylose sugars were completely utilized by Clavispora lusitaniae QG1 (MN592676) and gave 100% ethanol yield. This study optimizes both fermentation process and pretreatment of sugarcane bagasse to maximize bioethanol yield and demonstrates the ability of isolated strain to effectively utilize xylose as a carbon source. The desirable characteristics depicted by strain Clavispora lusitaniae shows its promising utilization in management of industrial waste like sugarcane bagasse by its conversion into renewable biofuels like bioethanol.

Cultivable bacteria in the supraglacial lake formed after a glacial lake outburst flood in northern Pakistan.

Recently, a supraglacial lake formed as a result of a glacial lake outburst flood (GLOF) in the Dook Pal Glacier. Lake debris and meltwater samples were collected from the supraglacial lake to determine bacterial diversity. Geochemical analyses of samples showed free amino acids (FAAs), anions, cations, and heavy metals. Comparable viable bacterial counts were observed in meltwater and debris samples. Using R2A media, a total of 52 bacterial isolates were identified: 40 from debris and 12 from meltwater. The relative abundance of Gram-positive (80.8%) bacteria was greater than Gram-negative (19.2%). Molecular identification of these isolates revealed that meltwater was dominated by Firmicutes (41.6%) and Proteobacteria (41.6%), while lake debris was dominated by Firmicutes (65.0%). The isolates belonged to 14 genera with the greatest relative abundance in Bacillus. Tolerance level of isolates to salts was high. Most of the Gram-positive bacteria were eurypsychrophiles, while most of the Gram-negative bacteria were stenopsychrophiles. Gram-negative bacteria displayed a higher minimum inhibitory concentration of selected heavy metals and antibiotics than Gram-positive. This first-ever study of culturable bacteria from a freshly formed supraglacial lake improves our understanding of the bacterial diversity and antibiotic resistance released from the glaciers as a result of GLOF.

High prevalence of antibiotic-resistant and metal-tolerant cultivable bacteria in remote glacier environment.

Studies of antibiotic-resistant bacteria (ARB) have mainly originated from anthropic-influenced environments, with limited information from pristine environments. Remote cold environments are major reservoirs of ARB and have been determined in polar regions; however, their abundance in non-polar cold habitats is underexplored. This study evaluated antibiotics and metals resistance profiles, prevalence of antibiotic resistance genes (ARGs) and metals tolerance genes (MTGs) in 38 ARB isolated from the glacier debris and meltwater from Baishui Glacier No 1, China. Molecular identification displayed Proteobacteria (39.3%) predominant in debris, while meltwater was dominated by Actinobacteria (30%) and Proteobacteria (30%). Bacterial isolates exhibited multiple antibiotic resistance index values > 0.2. Gram-negative bacteria displayed higher resistance to antibiotics and metals than Gram-positive. PCR amplification exhibited distinct ARGs in bacteria dominated by ß-lactam genes blaCTX-M (21.1-71.1%), blaACC (21.1-60.5%), tetracycline-resistant gene tetA (21.1-60.5%), and sulfonamide-resistant gene sulI (18.4-52.6%). Moreover, different MTGs were reported in bacterial isolates, including mercury-resistant merA (21.1-63.2%), copper-resistant copB (18.4-57.9%), chromium-resistant chrA (15.8-44.7%) and arsenic-resistant arsB (10.5-44.7%). This highlights the co-selection and co-occurrence of MTGs and ARGs in remote glacier environments. Different bacteria shared same ARGs, signifying horizontal gene transfer between species. Strong positive correlation among ARGs and MTGs was reported. Metals tolerance range exhibited that Gram-negative and Gram-positive bacteria clustered distinctly. Gram-negative bacteria were significantly tolerant to metals. Amino acid sequences of blaACC,blaCTX-M,blaSHV,blaampC,qnrA, sulI, tetA and blaTEM revealed variations. This study presents promising ARB, harboring ARGs with variations in amino acid sequences, highlighting the need to assess the transcriptome study of glacier bacteria conferring ARGs and MTGs.

Isolation and characterization of a cold-active, detergent-stable protease from Serratia sp. TGS1.

Psychrophiles are cold-adapted microorganisms living in cold regions and are known to generate cold-active enzymes such as proteases, lipases, and peptidases. These types of enzymes are a major part of the market of the food and textile sector. This study aimed to isolate and characterize the cold-active and detergent-stable, extracellular protease from psychotrophic bacteria Serratia sp. TGS1 (OQ654005). Protease was purified by gel permeation chromatography using Sephadex G-75. The specific activity of the purified protease was 250 U/mg at 15°C, with a purification fold of 5.68 and a percentage yield of 60%. The cold active protease was stable within a temperature range of 5-30°C and a pH range of 6-10. Ca+2 and Mg+2 enhanced its activity while chelators like ethylenediaminetetraacetic acid inhibited cold active protease, showing it as metalloprotease in nature. The enzyme was sensitive to Cu+2 , Zn+2 , and Hg+2 , and the proteolytic activity decreased upon treatment with heavy metals. The molecular weight of the protease was estimated to be 47 kDa using sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. Proteins within a specific range of molecular weight possess desirable properties for industrial enzyme use. By working on a specific range, the researchers intended to examine an enzyme to examine its specific characteristics. The purified protease showed high stability to detergents like SDS, Tween 20, Tween 60, and Triton X. The maximum velocity Vmax and Km values were 59.90 mg/min/mL and 1.53 mg/mL, respectively. The obtained protease exhibited an interesting activity at a broad range of pH (6-10) and stability at low temperatures (5-30°C) and detergents. Such enzymatic features of versatile and potent cold-active enzymes enhance their industrial applications to meet food, dairy, and laundry requirements.

Quorum Quenchers from Reynoutria japonica in the Battle against Methicillin-Resistant Staphylococcus aureus (MRSA).

Over the past decade, methicillin-resistant Staphylococcus aureus (MRSA) has become a major source of biofilm formation and a major contributor to antimicrobial resistance. The genes that govern biofilm formation are regulated by a signaling mechanism called the quorum-sensing system. There is a need for new molecules to treat the infections caused by dangerous pathogens like MRSA. The current study focused on an alternative approach using juglone derivatives from Reynoutria japonica as quorum quenchers. Ten bioactive compounds from this plant, i.e., 2-methoxy-6-acetyl-7-methyljuglone, emodin, emodin 8-o-b glucoside, polydatin, resveratrol, physcion, citreorosein, quercetin, hyperoside, and coumarin were taken as ligands and docked with accessory gene regulator proteins A, B, and C and the signal transduction protein TRAP. The best ligand was selected based on docking score, ADMET properties, and the Lipinski rule. Considering all these parameters, resveratrol displayed all required drug-like properties with a docking score of -8.9 against accessory gene regulator protein C. To further assess the effectiveness of resveratrol, it was compared with the commercially available antibiotic drug penicillin. A comparison of all drug-like characteristics showed that resveratrol was superior to penicillin in many aspects. Penicillin showed a binding affinity of -6.7 while resveratrol had a score of -8.9 during docking. This was followed by molecular dynamic simulations wherein inhibitors in complexes with target proteins showed stability inside the active site during the 100 ns simulations. Structural changes due to ligand movement inside the cavity were measured in the protein targets, but they remained static due to hydrogen bonds. The results showed acceptable pharmacokinetic properties for resveratrol as compared to penicillin. Thus, we concluded that resveratrol has protective effects against Staphylococcus aureus infections and that it suppresses the quorum-sensing ability of this bacterium by targeting its infectious proteins.

Transcriptional and biochemical analyses of Planomicrobium strain AX6 from Qinghai-Tibetan Plateau, China, reveal hydrogen peroxide scavenging potential.

BACKGROUND: The bacterial mechanisms responsible for hydrogen peroxide (H2O2) scavenging have been well-reported, yet little is known about how bacteria isolated from cold-environments respond to H2O2 stress. Therefore, we investigated the transcriptional profiling of the Planomicrobium strain AX6 strain isolated from the cold-desert ecosystem in the Qaidam Basin, Qinghai-Tibet Plateau, China, in response to H2O2 stress aiming to uncover the molecular mechanisms associated with H2O2 scavenging potential. METHODS: We investigated the H2O2-scavenging potential of the bacterial Planomicrobium strain AX6 isolated from the cold-desert ecosystem in the Qaidam Basin, Qinghai-Tibet Plateau, China. Furthermore, we used high-throughput RNA-sequencing to unravel the molecular aspects associated with the H2O2 scavenging potential of the Planomicrobium strain AX6 isolate. RESULTS: In total, 3,427 differentially expressed genes (DEGs) were identified in Planomicrobium strain AX6 isolate in response to 4 h of H2O2 (1.5 mM) exposure. Besides, Kyoto Encyclopedia of Genes and Genomes pathway and Gene Ontology analyses revealed the down- and/or up-regulated pathways following H2O2 treatment. Our study not only identified the H2O2 scavenging capability of the strain nevertheless also a range of mechanisms to cope with the toxic effect of H2O2 through genes involved in oxidative stress response. Compared to control, several genes coding for antioxidant proteins, including glutathione peroxidase (GSH-Px), Coproporphyrinogen III oxidase, and superoxide dismutase (SOD), were relatively up-regulated in Planomicrobium strain AX6, when exposed to H2O2. CONCLUSIONS: Overall, the results suggest that the up-regulated genes responsible for antioxidant defense pathways serve as essential regulatory mechanisms for removing H2O2 in Planomicrobium strain AX6. The DEGs identified here could provide a competitive advantage for the existence of Planomicrobium strain AX6 in H2O2-polluted environments.

Structural and compositional segregation of the gut microbiota in HCV and liver cirrhotic patients: A clinical pilot study.

Gut microbial dysbiosis during the development of Hepatitis C virus and liver-related diseases is not well studied. Nowadays, HCV and liver cirrhosis are the major concerns that cause gut bacterial alteration, which leads to dysbiosis. For this purpose, the present study was aimed at correlating the gut bacterial community of the control group in comparison to HCV and liver cirrhotic patients. A total of 23 stool samples were collected, including control (9), liver cirrhotic (8), and HCV (6). The collected samples were subjected to 16 S rRNA Illumina gene sequencing. In comparison with control, a significant gut bacterial alteration was observed in the progression of HCV and liver cirrhosis. Overall, Firmicutes were significantly abundant in the whole study. No significant difference was observed in the alpha diversity of the control and patient studies. Additionally, the beta diversity based on non-metric multidimensional scaling (NMDS) has a significant difference (p = 0.005) (ANOSIM R2 = 0.14) in all groups. The discriminative results based on the LEfSe tool revealed that the HCV-infected patients had higher Enterobacteriaceae and Enterobacterial, as well as Lactobacillus and Bacilli in comparison than the liver-cirrhotic patients. These taxa were significantly different from the control group (p < 0.05). Regarding prospects, a detailed analysis of the function through metagenomics and transcriptomics is needed.

Phosphate solubilizing epilithic and endolithic bacteria isolated from clastic sedimentary rocks, Murree lower Himalaya, Pakistan.

Rock microbes are capable to solubilize phosphate present in the rocks.. In this study, we focused on the isolation of phosphate solubilizing bacteria from rocks of Murree, Pakistan. Both endolithic and epilithic bacteria were screened for phosphate solubilization. Three bacterial strains were selected based on halozone formation inNational Botanical Research Institute for phosphate) medium supplemented with TCP (tribasic calcium phosphate). The solubilization index for these bacteria was recorded as 4.29, 4.03 and 3.99. The pH of the medium dropped from 7.0 to 4.0 after 5 days with continuous shaking at 150 rpm, which facilitate the phosphate solubilization. The strains P26, P4 and N27 were identified as Pseudomonas putida strain (KT004381), Pseudomonas grimontii (KT223621) and Alcaligenes faecalis (KT004385). Strain P26 showed maximum phosphate solubilization (367.54 µg/ml), while P4 and N27 showed 321.88 and 291.36 µg/ml after 3 days of incubation. Such inorganic phosphate solubilization could be attributed to the organic acids production by bacteria. The presence of organic acids is determined by high-performance liquid chromatography. Three different types of acids, gluconic, oxalic and malic acid were the dominant acids found in the culture medium. It may be assumed that these bacteria can play a role in weathering of rocks as well. PSB is likely to serve as an efficient biofertilizer, especially in areas deficient in P to increase the overall performance of crops.

Seasonal taxonomic composition of microbial communal shaping the bioaerosols milieu of the urban city of Lanzhou.

Here, the taxonomical composition and seasonal dynamics of airborne microbial communities were described in the urban city of Lanzhou, Northwest China. Year-long samples were studied in two filter membranes (Quartz and PTFE). Higher microbial loads were reported in the PTFE than in the quartz filter. Onefold decrease was reported in bacterial loads in spring and summer than winter and autumn for both filters. The fungal loadings were lowest during winter and highest during autumn, followed by summer. The microbial communities included Actinobacteria and Proteobacteria, Ascomycota, and Basidiomycota as major components. Maximum abundance of the members from Gammaproteobacteria, Coriobacteria and Clostridia were studied in all seasons on PTFE membrane, followed by, Erysipelotrichia, Negativicutes and Fusobacteria. Members of Actinobacteria and Bacilli showed higher abundance in spring and winter, with a small proportion during autumn. Members of Clostridia, Gammaproteobacteria, Bacilli, and Actinobacteria showed maximum abundance on the quartz filter in all the seasons. Similarly, on the PTFE, fungi including Dothideomycetes and Agaricomycetes were dominant, followed by Saccharomycetes during summer and winter. The result showed that PM2.5, SO42-, NO2-, Na+, EC, and OC are important environmental parameters influencing the seasonal microbial community. However, the relation of the microbiome with the environment cannot be confidently defined because the environmental factors are changeable and yet interrelated.

Cave Microbes as a Potential Source of Drugs Development in the Modern Era.

The world is constantly facing threats, including the emergence of new pathogens and antibiotic resistance among extant pathogens, which is a matter of concern. Therefore, the need for natural and effective sources of drugs is inevitable. The ancient and pristine ecosystems of caves contain a unique microbial world and could provide a possible source of antimicrobial metabolites. The association between humans and caves is as old as human history itself. Historically, cave environments have been used to treat patients with respiratory tract infections, which is referred to as speleotherapy. Today, the pristine environment of caves that comprise a poorly explored microbial world is a potential source of antimicrobial and anticancer drugs. Oligotrophic conditions in caves enhance the competition among microbial communities, and unique antimicrobial agents may be used in this competition. This review suggests that the world needs a novel and effective source of drug discovery. Therefore, being the emerging spot of modern human civilization, caves could play a crucial role in the current medical crisis, and cave microorganisms may have the potential to produce novel antimicrobial and anticancer drugs.

Soot biodegradation by psychrotolerant bacterial consortia.

To probe the bioavailability of soot released into the atmosphere is pivotal to understanding their environmental impacts. Soot aerosol absorbs organic matter, creating a hot spot for biogeochemical transformation and the global carbon cycle. Soot primarily contains condensed aromatics chemically recalcitrant; however, oligotrophic microorganisms might use it as a nutritional source. This study investigated the influence of psychrotolerant bacterial consortia on soot. Significant increase in the bacterial biomass, reduction in water-insoluble organic carbon (OC) and elemental carbon (EC) in soot residues and increase in water-soluble OC in the filtrate signifies the use of soot as a carbon and nutritional source. The influence on morphology and composition of soot was reported using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy, and Energy Dispersive X-Ray analysis (EDX). The FTIR analysis showed significant variations in the pattern of soot spectra, suggesting degradation. Elemental analysis and EDX showed a reduction in carbon percentage. Besides, the reduction of optical density with incubation time signifies the OC and EC consumption. This study shows that soot can be a substrate and pivotal factor in the microbial food web. Nowadays, soot emission to the environment is growing; therefore, soot involvement in microbe-mediated processes should be closely focused.

Bacterial diversity patterns of desert dunes in the northeastern Qinghai-Tibet Plateau, China.

Limited knowledge about the variation patterns of bacterial community composition in the sand and vegetative ecosystems confines our understanding regarding the contribution of the sand dune to desert areas. In this study, 454 pyrosequencing platforms were adopted to determine the community structure of bacteria and diversity of sand dunes in northeastern Qinghai-Tibet Plateau, China: 50 cm deep, rhizosphere, physical crusts, and biological crusts representing sand and vegetative ecosystems, respectively. The findings revealed significant variation in bacterial diversities and the structure of communities in the sand and vegetative ecosystems. The dominant bacterial phyla of sand and vegetative ecosystems were Firmicutes (47%), Actinobacteria (21%), Proteobacteria (16%), and Bacteroidetes (13%), while Lactococcus (50%) was found to be the dominant genus. Furthermore, samples with high alpha-diversity indices (Chao 1 and Shannon) for the vegetative ecosystem have the lowest modularity index and the largest number of biomarkers, with some exceptions. Redundancy analysis exhibited that environmental factors could explain 72% (phyla) and 67% (genera) of the bacterial communities, with EC, TC, and TOC being the major driving factors. This study expands our understanding of bacterial community composition in the desert ecosystem. The findings suggest that variations in the sand and vegetative ecosystems, such as those predicted by environmental factors, may reduce the abundance and diversity of bacteria, a response that likely affects the provision of key ecosystem processes by desert regions.

Effect of pyrene and phenanthrene in shaping bacterial communities in seagrass meadows sediments.

Polycyclic aromatic hydrocarbons (PAHs), originating from anthropogenic and natural sources, are highly concerned environmental pollutants. This study investigated the impact of two model PAHs (pyrene and phenanthrene) on bacterial community succession in the seagrass meadows sediment in a lab-scale microcosm. Halophila ovalis sediment slurry microcosms were established, one group was placed as a control, and the other two were treated with pyrene and phenanthrene. Bacterial community succession in response to respective PAHs was investigated by 16S rRNA amplicon sequencing. The results demonstrated that bacterial diversity decrease in each microcosm during the incubation process; however, the composition of bacterial communities in each microcosm was significantly different. Proteobacteria (37-89%), Firmicutes (9-41%), and Bacteroides (7-21%) were the predominant group at the phylum levels. Their abundance varies during the incubation process. Several previously reported hydrocarbon-degrading genera, such as Pseudomonas, Spinghobium, Sphingobacterium, Mycobacterium, Pseudoxanthomonas, Idiomarina, Stenotrophomonas, were detected in higher abundance in pyrene- and phenanthrene-treated microcosms. However, these genera were distinctly distributed in the pyrene and phenanthrene treatments, suggesting that certain bacterial groups favorably degrade different PAHs. Statistical analyses, such as ANOSIM and PERMANOVA, also revealed that significant differences existed among the treatments' bacterial consortia (P < 0.05). This work showed that polycyclic aromatic hydrocarbon significantly affects bacterial community succession, and different PAHs might influence the bacterial community succession differently.

Epidemiology of molecular probes in Xpert MTB/RIF assay in Khyber Pakhtunkhwa, Pakistan.

Regardless of a plethora of advanced diagnostics, TB and drug resistance remains a principal killer. We proposed gold nanoparticles (AuNPs) attached with probes to enhance the efficiency of GeneXpert MTB/RIF assay instead of conventional dye probes for molecular detection. A total of 15,000 samples were collected from TB suspects and subjected to Xpert MTB/RIF assay, where 6800 (45.3%) were detected as MTB positive, 280 (4.3%) were detected to harbor mutations in the RRDR, while invalid /errors were found in 690 (4.6%) cases. The mutations were detected by probe E, 199 (71.1%), while probes B and D, 30 and 26 (10% and 9%), respectively. In the Xpert MTB/RIF Assay were found mutations picked by probes E and B codons 529-533 (71%) and 512-518 (10%), respectively. The fast-rising works of TB nano-diagnostics, of Xpert probes, may improve by the applications of gold nanoparticle probes.

Bacterial Diversity and Communities Structural Dynamics in Soil and Meltwater Runoff at the Frontier of Baishui Glacier No.1, China.

Comprehensive knowledge of bacterial ecology mainly in supraglacial habitats is pivotal particularly at the frontier of accelerated glacier retreat. In this study, bacterial diversity and community composition in glacial soil and meltwater runoff at the frontier of Baishui Glacier No.1 were evaluated using high throughput sequencing. Significant variations in the physiochemical parameters formed an ecological gradient between soil and meltwater runoff. Based on the richness and evenness indexes, the bacterial diversity was relatively higher in soil compared with meltwater runoff. Hierarchical clustering and bi-plot ordination revealed that the taxonomic composition of soil samples was highly similar and significantly influenced by the ecological parameters than the meltwater runoff. The overall relative abundance trend of bacterial phyla and genera were greatly varied in soil and water samples. The relative abundance of Proteobacteria was higher in water runoff samples (40.5-87%) compared with soil samples (32-52.7%). Proteobacteria, Firmicutes, and a little part of Cyanobacteria occupied a major portion of water runoff while the soil was dominated by Acidobacteria (6-16.2%), Actinobacteria (5-16%), Bacteroidetes (0.5-8.8%), and Cyanobacteria (0.1-8.3%) besides Proteobacteria and Firmicutes. Higher numbers of biomarkers were found in soil group compared with the water group. The study area is diverse in terms of richness, while community structures are not evenly distributed. This study provides a preliminary understanding of the bacterial diversity and shifts in community structure in soil and meltwater runoff at the frontier of the glacial. The findings revealed that the environmental factors are a significantly strong determinant of bacterial community structures in such a closely linked ecosystem.