Unraveling the mechanism of norfloxacin removal and fate of antibiotics resistance genes (ARGs) in the sulfur-mediated autotrophic denitrification via metagenomic and metatranscriptomic analyses.

The co-contamination of antibiotics and nitrogen has attracted widespread concerns due to its potential harm to ecological safety and human health. Sulfur-driven autotrophic denitrification (SAD) with low sludge production rate was adopted to treat antibiotics laden-organic deficient wastewater. Herein, a lab-scale sequencing batch reactor (SBR) was established to explore the simultaneous removal of nitrate and antibiotics, i.e. Norfloxacin (NOR), as well as microbial response mechanism of SAD sludge system towards NOR exposure. About 80.78 % of NOR was removed by SAD sludge when the influent NOR level was 0.5 mg/L, in which biodegradation was dominant removal route. The nitrate removal efficiency decreased slightly from 98.37 ± 0.58 % to 96.58 ± 1.03 % in the presence of NOR. Thiobacillus and Sulfurimonas were the most abundant sulfur-oxidizing bacteria (SOB) in SAD system, but Thiobacillus was more sensitive to NOR. The up-regulated genes related to Xenobiotics biodegradation and metabolism and CYP450 indicated the occurrence of NOR biotransformation in SAD system. The resistance of SAD sludge to the exposure of NOR was mainly ascribed to antibiotic efflux. And the effect of antibiotic inactivation was enhanced after long-term fed with NOR. The NOR exposure resulted in the increased level of antibiotics resistance genes (ARGs) and mobile genetic elements (MGEs). Besides, the enhanced ARG-MGE co-existence patterns further reveals the higher horizontal mobility potential of ARGs under NOR exposure pressures. The most enriched sulfur oxidizing bacterium Thiobacillus was a potential host for most of ARGs. This study provides a new insight for the treatment of NOR-laden wastewater with low C/N ratio based on the sulfur-mediated biological process.

Material and microbial perspectives on understanding the role of biochar in mitigating ammonia inhibition during anaerobic digestion.

With the increasing adoption of carbon-based strategies to enhance methanogenic processes, there is a growing concern regarding the correlation between biochar properties and its stimulating effects on anaerobic digestion (AD) under ammonia inhibition. This study delves into the relevant characteristics and potential mechanisms of biochar in the context of AD system under ammonia inhibition. The introduction of optimized biochar, distinguished by rich CO bond, abundant defect density, and high electronic capacity, resulted in a significant reduction in the lag period of anaerobic digestion system under 5.0 g/L ammonia stress, approximately by around 63 % compared to the control one. Biochar helps regulate the community structure, promotes the accumulation of acetate-consuming bacteria, in the AD system under ammonia inhibition. More examinations show that biochar promotes direct interspecies electron transfer in AD system under ammonia inhibition, as evidenced by diminished levels of bound electroactive extracellular polymeric substances, increased abundance of electroactive bacteria, and notably, the up-regulation of direct interspecies electron transfer associated genes, including the conductive pili and Cytochrome C genes, as revealed by meta-transcriptomic analysis. Additionally, gene expression related to proteins associated with ammonium detoxification were found to be up-regulated in systems supplemented with biochar. These findings provide essential evidence and insights for the selection and potential engineering of effective biochar to enhance AD performance under ammonia inhibition.

Metatranscriptomics revealed the molecular characterization of circulating enterovirus strains causing aseptic meningitis in children in Wuxi, China.

Enteroviruses are major etiological agents of aseptic meningitis globally, however information on circulating enterovirus types associated with this disease in Wuxi, China is limited. In this study, cerebrospinal fluid samples were collected from 20 pediatric aseptic meningitis cases in a Wuxi hospital in 2020 and subjected to metagenomic analysis to detect pathogens. Enterovirus B was detected in 9 cases, including 7 echovirus 18 (E18) and 2 echovirus 11 (E11) strains. The E18 strains exhibited 87.5-98.2% nucleotide identity and phylogenetically clustered with other China E18 strains, while the E11 strains showed 97.59% identity and clustered within the D5 subgroup along with other China E11 strains. One E18 strain was identified as a novel recombinants with a distinct recombination breakpoint within 3D gene. These findings expand knowledge on enteroviruses associated with pediatric aseptic meningitis in Wuxi, and highlight the circulation of genetically diverse E18 and E11 strains, including novel E18 recombinants. Characterization of enterovirus diversity by metagenomic analysis is important for molecular diagnosis and epidemiological tracking of aseptic meningitis cases. Continued surveillance of circulating enterovirus strains in Wuxi that may cause future outbreaks is warranted.

Identification of novel mammalian viruses in tree shrews ( Tupaia belangeri chinensis).

The Chinese tree shrew ( Tupaia belangeri chinensis), a member of the mammalian order Scandentia, exhibits considerable similarities with primates, including humans, in aspects of its nervous, immune, and metabolic systems. These similarities have established the tree shrew as a promising experimental model for biomedical research on cancer, infectious diseases, metabolic disorders, and mental health conditions. Herein, we used meta-transcriptomic sequencing to analyze plasma, as well as oral and anal swab samples, from 105 healthy asymptomatic tree shrews to identify the presence of potential zoonotic viruses. In total, eight mammalian viruses with complete genomes were identified, belonging to six viral families, including Flaviviridae, Hepeviridae, Parvovirinae, Picornaviridae, Sedoreoviridae, and Spinareoviridae. Notably, the presence of rotavirus was recorded in tree shrews for the first time. Three viruses - hepacivirus 1, parvovirus, and picornavirus - exhibited low genetic similarity (<70%) with previously reported viruses at the whole-genome scale, indicating novelty. Conversely, three other viruses - hepacivirus 2, hepatovirus A and hepevirus - exhibited high similarity (>94%) to known viral strains. Phylogenetic analyses also revealed that the rotavirus and mammalian orthoreovirus identified in this study may be novel reassortants. These findings provide insights into the diverse viral spectrum present in captive Chinese tree shrews, highlighting the necessity for further research into their potential for cross-species transmission.

A mixed blessing of influent leachate microbes in downstream biotreatment systems of a full-scale landfill leachate treatment plant.

In landfill leachate treatment plants (LLTPs), the microbiome plays a pivotal role in the decomposition of organic compounds, reduction in nutrient levels, and elimination of toxins. However, the effects of microbes in landfill leachate influents on downstream treatment systems remain poorly understood. To address this knowledge gap, we collected 23 metagenomic and 12 metatranscriptomic samples from landfill leachate and activated sludge from various treatment units in a full-scale LLTP. We successfully recovered 1,152 non-redundant metagenome-assembled genomes (MAGs), encompassing a wide taxonomic range, including 48 phyla, 95 classes, 166 orders, 247 families, 238 genera, and 1,152 species. More diverse microbes were observed in the influent leachate than in the downstream biotreatment systems, among which, an unprecedented ∼30 % of microbes with transcriptional expression migrated from the influent to the biological treatment units. Network analysis revealed that 399 shared MAGs across the four units exhibited high node centrality and degree, thus supporting enhanced interactions and increased stability of microbial communities. Functional reconstruction and genome characterization of MAGs indicated that these shared MAGs possessed greater capabilities for carbon, nitrogen, sulfur, and arsenic metabolism compared to non-shared MAGs. We further identified a novel species of Zixibacteria in the leachate influent with discrete lineages from those in other environments that accounted for up to 17 % of the abundance of the shared microbial community and exhibited notable metabolic versatility. Meanwhile, we presented groundbreaking evidence of the involvement of Zixibacteria-encoded genes in the production of harmful gas emissions, such as N2O and H2S, at the transcriptional level, thus suggesting that influent microbes may pose safety risks to downstream treatment systems. In summary, this study revealed the complex impact of the influent microbiome on LLTP and emphasizes the need to consider these microbial characteristics when designing treatment technologies and strategies for landfill leachate management.

Microscopic and metatranscriptomic analyses revealed unique cross-domain parasitism between phylum Candidatus Patescibacteria/candidate phyla radiation and methanogenic archaea in anaerobic ecosystems.

To verify whether members of the phylum Candidatus Patescibacteria parasitize archaea, we applied cultivation, microscopy, metatranscriptomic, and protein structure prediction analyses on the Patescibacteria-enriched cultures derived from a methanogenic bioreactor. Amendment of cultures with exogenous methanogenic archaea, acetate, amino acids, and nucleoside monophosphates increased the relative abundance of Ca. Patescibacteria. The predominant Ca. Patescibacteria were families Ca. Yanofskyibacteriaceae and Ca. Minisyncoccaceae, and the former showed positive linear relationships (r2 ≥ 0.70) Methanothrix in their relative abundances, suggesting related growth patterns. Methanothrix and Methanospirillum cells with attached Ca. Yanofskyibacteriaceae and Ca. Minisyncoccaceae, respectively, had significantly lower cellular activity than those of the methanogens without Ca. Patescibacteria, as extrapolated from fluorescence in situ hybridization-based fluorescence. We also observed that parasitized methanogens often had cell surface deformations. Some Methanothrix-like filamentous cells were dented where the submicron cells were attached. Ca. Yanofskyibacteriaceae and Ca. Minisyncoccaceae highly expressed extracellular enzymes, and based on structural predictions, some contained peptidoglycan-binding domains with potential involvement in host cell attachment. Collectively, we propose that the interactions of Ca. Yanofskyibacteriaceae and Ca. Minisyncoccaceae with methanogenic archaea are parasitisms.IMPORTANCECulture-independent DNA sequencing approaches have explored diverse yet-to-be-cultured microorganisms and have significantly expanded the tree of life in recent years. One major lineage of the domain Bacteria, Ca. Patescibacteria (also known as candidate phyla radiation), is widely distributed in natural and engineered ecosystems and has been thought to be dependent on host bacteria due to the lack of several biosynthetic pathways and small cell/genome size. Although bacteria-parasitizing or bacteria-preying Ca. Patescibacteria have been described, our recent studies revealed that some lineages can specifically interact with archaea. In this study, we provide strong evidence that the relationship is parasitic, shedding light on overlooked roles of Ca. Patescibacteria in anaerobic habitats.

Analysis of endoglucanases production using metatranscriptomics and proteomics approach.

The cellulases are among the most used enzyme in industries for various purposes. They add up to the green economy perspective and cost-effective production of enterprises. Biorefineries, paper industries, and textile industries are foremost in their usage. The production of endoglucanases from microorganisms is a valuable resource and can be exploited with the help of biotechnology. The present review provides some insight into the uses of endoglucanases in different industries and the potent fungal source of these enzymes. The advances in the enzyme technology has helped towards understanding some pathways to increase the production of industrial enzymes from microorganisms. The proteomics analysis and systems biology tools also help to identify these pathways for the enhanced production of such enzymes. This review deciphers the use of proteomics tools to analyze the potent microorganisms and identify suitable culture conditions to increase the output of endoglucanases. The review also includes the role of quantitative proteomics which is a powerful technique to get results faster and more timely. The role of metatranscriptomic approaches are also described which are helpful in the enzyme engineering for their efficient use under industrial conditions. Conclusively, this review helps to understand the challenges faced in the industrial use of endoglucanases and their further improvement.

New insights into the typical nitrogen-containing heterocyclic compound-quinoline degradation and detoxification by microbial consortium: Integrated pathways, meta-transcriptomic analysis and toxicological evaluation.

As the primary source of COD in industrial wastewater, quinoline has aroused increasing attention because of its potential teratogenic, carcinogenic, and mutagenic effects in the environment. The activated sludge isolate quinoline-degrading microbial consortium (QDMC) efficiently metabolizes quinoline. However, the molecular underpinnings of the degradation mechanism of quinoline by QDMC have not been elucidated. High-throughput sequencing revealed that the dominant genera included Diaphorobacter, Bacteroidia, Moheibacter and Comamonas. Furthermore, a positive strong correlation was observed between the key bacterial communities (Diaphorobact and Bacteroidia) and quinoline degradation. According to metatranscriptomics, genes associated with quorum sensing, ABC transporters, component systems, carbohydrate, aromatic compound degradation, energy metabolism and amino metabolism showed high expression, thus improving adaptability of microbial community to quinoline stress. In addition, the mechanism of QDMC in adapting and resisting to extreme environmental conditions in line with the corresponding internal functional properties and promoting biogegradation efficiency was illustrated. Based on the identified products, QDMC effectively mineralized quinoline into low-toxicity metabolites through three major metabolic pathways, including hydroxyquinoline, 1,2,3,4-H-quinoline, 5,6,7,8-tetrahydroquinoline and 1-oxoquinoline pathways. Finally, toxicological, genotoxicity and phytotoxicity studies supported the detoxification of quinoline by the QDMC. This study provided a promising approach for the stable, environmental-friendly and efficient bioremediation applications for quinoline-containing wastewater.

Metatranscriptomic data mining together with microfluidic card uncovered the potential pathogens and seasonal RNA viral ecology in a drinking water source.

AIMS: Despite metatranscriptomics becoming an emerging tool for pathogen surveillance, very little is known about the feasibility of this approach for understanding the fate of human-derived pathogens in drinking water sources. METHODS AND RESULTS: We conducted multiplexed microfluidic cards and metatranscriptomic sequencing of the drinking water source in a border city of North Korea in four seasons. Microfluidic card detected norovirus, hepatitis B virus (HBV), enterovirus, and Vibrio cholerae in the water. Phylogenetic analyses showed that environmental-derived sequences from norovirus GII.17, genotype C of HBV, and coxsackievirus A6 (CA6) were genetically related to the local clinical isolates. Meanwhile, metatranscriptomic assembly suggested that several bacterial pathogens, including Acinetobacter johnsonii and V. cholerae might be prevalent in the studied region. Metatranscriptomic analysis recovered 349 species-level groups with substantial viral diversity without detection of norovirus, HBV, and CA6. Seasonally distinct virus communities were also found. Specifically, 126, 73, 126, and 457 types of viruses were identified in spring, summer, autumn, and winter, respectively. The viromes were dominated by the Pisuviricota phylum, including members from Marnaviridae, Dicistroviridae, Luteoviridae, Potyviridae, Picornaviridae, Astroviridae, and Picobirnaviridae families. Further phylogenetic analyses of RNA (Ribonucleic Acid)-dependent RNA polymerase (RdRp) sequences showed a diverse set of picorna-like viruses associated with shellfish, of which several novel picorna-like viruses were also identified. Additionally, potential animal pathogens, including infectious bronchitis virus, Bat dicibavirus, Bat nodavirus, Bat picornavirus 2, infectious bursal disease virus, and Macrobrachium rosenbergii nodavirus were also identified. CONCLUSIONS: Our data illustrate the divergence between microfluidic cards and metatranscriptomics, highlighting that the combination of both methods facilitates the source tracking of human viruses in challenging settings without sufficient clinical surveillance.

VIGA: a one-stop tool for eukaryotic virus identification and genome assembly from next-generation-sequencing data.

Identification of viruses and further assembly of viral genomes from the next-generation-sequencing data are essential steps in virome studies. This study presented a one-stop tool named VIGA (available at https://github.com/viralInformatics/VIGA) for eukaryotic virus identification and genome assembly from NGS data. It was composed of four modules, namely, identification, taxonomic annotation, assembly and novel virus discovery, which integrated several third-party tools such as BLAST, Trinity, MetaCompass and RagTag. Evaluation on multiple simulated and real virome datasets showed that VIGA assembled more complete virus genomes than its competitors on both the metatranscriptomic and metagenomic data and performed well in assembling virus genomes at the strain level. Finally, VIGA was used to investigate the virome in metatranscriptomic data from the Human Microbiome Project and revealed different composition and positive rate of viromes in diseases of prediabetes, Crohn's disease and ulcerative colitis. Overall, VIGA would help much in identification and characterization of viromes, especially the known viruses, in future studies.

Viral Diversity in Samples of Freshwater Gastropods Benedictia baicalensis (Caenogastropoda: Benedictiidae) Revealed by Total RNA-Sequencing.

Previously, the main studies were focused on viruses that cause disease in commercial and farmed shellfish and cause damage to food enterprises (for example, Ostreavirusostreidmalaco1, Aurivirus haliotidmalaco1 and Aquabirnavirus tellinae). Advances in high-throughput sequencing technologies have extended the studies to natural populations of mollusks (and other invertebrates) as unexplored niches of viral diversity and possible sources of emerging diseases. These studies have revealed a huge diversity of mostly previously unknown viruses and filled gaps in the evolutionary history of viruses. In the present study, we estimated the viral diversity in samples of the Baikal endemic gastropod Benedictia baicalensis using metatranscriptomic analysis (total RNA-sequencing); we were able to identify a wide variety of RNA-containing viruses in four samples (pools) of mollusks collected at three stations of Lake Baikal. Most of the identified viral genomes (scaffolds) had only distant similarities to known viruses or (in most cases) to metagenome-assembled viral genomes from various natural samples (mollusks, crustaceans, insects and others) mainly from freshwater ecosystems. We were able to identify viruses similar to those previously identified in mollusks (in particular to the picornaviruses Biomphalaria virus 1 and Biomphalaria virus 3 from the freshwater gastropods); it is possible that picorna-like viruses (as well as a number of other identified viruses) are pathogenic for Baikal gastropods. Our results also suggested that Baikal mollusks, like other species, may bioaccumulate or serve as a reservoir for numerous viruses that infect a variety of organisms (including vertebrates).

Autoinducer-2 quorum sensing regulates biofilm formation and chain elongation metabolic pathways to enhance caproate synthesis in microbial electrochemical system.

Quorum sensing (QS) have been explored extensively. However, most studies focused on N-acyl homoserine lactones (AHLs) participating in intraspecies QS. In this study, autoinducer-2 (AI-2, participating in interspecies QS) with different concentration was investigated for chain elongation in microbial electrosynthesis (MES). The results demonstrated that the R3 treatment, which involved adding 10 µM of 4,5-dihydroxy-2,3-pentanedione (DPD) in the reactor, exhibited the best performance. The concentration of caproate was increased by 66.88% and the redox activity of cathodic electroactive biofilms (EABs) was enhanced. Meanwhile, microbial community data indicated that Negativicutes relative abundance was increased obviously in R3 treatment. In this study, the transcriptome Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) databases were used to analyze the metabolic pathway of chain elongation involving fatty acid biosynthesis (FAB) pathway and reverse ß-oxidization (RBO) pathway. KEGG analysis revealed that fatty acid elongation metabolism (p < 0.001), tryptophan metabolism (p < 0.01), arginine and proline metabolism (p < 0.05) were significantly improved in R3 treatment. GO analysis suggested that R3 treatment mainly upregulated significantly transmembrane signaling receptor activity (p < 0.01), oxidoreductase activity (p < 0.05), and phosphorelay signal transduction (p < 0.05). Moreover, metatranscriptomic analyses also showed that R3 treatment could upregulate the LuxP extracellular receptor, LuxO transcriptional activator, LsrB periplasmic protein, and were beneficial to both FAB and RBO pathways. These findings provided a new insight into chain elongation in MES system.

Effect of inoculated Daqu on the spontaneous fermentation of Chinese liquor.

Inoculated fermentation is widely used to improve the efficiency and quality of food production. However, it is still unclear how the inoculated multi-species starters influence food fermentation. Here we prepared two different types of Daqu, with/without the inoculation of Bacillus licheniformis in spontaneous Daqu fermentation, and studied their effects on liquor fermentation. These two types of Daqu were different in microbial community, and the inoculated Daqu had significantly higher relative abundance of Bacillus (69.2%) and lower relative abundance of Lactobacillus (3.2%) than those of Daqu without inoculation (Bacillus, 13.5%; Lactobacillus, 14.0%). After using with these two types of Daqu, metatranscriptomic analysis revealed that Kazachstania, Naumovozyma, Saccharomyces, Nakaseomyces and Lactobacillus were the transcriptional active genera during liquor fermentation. The transcription of Lactobacillus decreased on days 10 and 20 in liquor fermentation with the inoculated Daqu. The transcription of Kazachstania, Naumovozyma and Saccharomyces decreased on day 10 but increased on day 20 with the inoculated Daqu. Although lactate dehydrogenase decreased in Lactobacillus, alcohol dehydrogenase, aldehyde dehydrogenase and lactate dehydrogenase increased in Saccharomyces on day 20 in fermentation with inoculated Daqu, it indicated an extended succession of Saccharomyces in liquor fermentation. This would facilitate the increase of ethanol, acetic acid and lactic acid contents in liquor fermentation with inoculated Daqu. This work would be beneficial for improving Chinese liquor fermentation.

Metatranscriptome revealed how carbon brush addition affected the fermentation of food wastewater in the low-temperature environment.

Improving the anaerobic digestion (AD) performance in low-temperature environments has become a key factor in the development of waste treatment and resource recovery in cold regions. The utilization of external carriers to form a biofilm is the simplest and most practical way to enhance the psychrophilic AD performance in cold regions. In this study, the effect of carrier addition on the fermentation performance of low-temperature (15 ± 2 °C) food wastewater was investigated by forming biofilms with carbon brushes. The results showed that although the biofilm formation enhanced methane yields (15.24%), it also caused more accumulation of propionic acid (306.99-626.89 mg/L), and the concentration of acetic acid (86.78-254.71 mg/L) was relatively low. The microbial community revealed the highest abundance of the fermentative bacterium Firmicutes and the carbon brush carrier significantly increased its relative abundance (23.74%). Metatranscriptomic sequencing revealed that the abundance level of Clostridium, Bacteroides, Sedimentibacter and Pelotomaculum was the highest, reaching 80% in all groups. In addition, the abundance level of electroactive microorganisms in biofilms was higher, while the fermentation bacteria and methanogens were lower. This showed that biofilm can enrich more electroactive microorganisms, and granular sludge needs to enrich more fermentation bacteria and methanogens to ensure metabolic activity. Further studies have found that carbon metabolism had the highest activity (27.86%-30.39%) and H+-transporting ATPase (atp) was the most dominant functional enzyme (85.50%-86.65%) involved in electron transport in low-temperature fermentation of food wastewater. Interestingly, these expression levels of active granular sludge were higher than the biofilm formed by carbon brushes. Meanwhile, analysis of the methanogenic pathway found that active granular sludge tends to be directly metabolized to realize acetate to acetyl-CoA by acetyl-CoA synthetase (ACSS), while biofilms were not significantly different in the two metabolic pathways of acetate. These results deepen the understanding of treating low-temperature food wastewater.

Effect of chlorine disinfectant influx on biological sewage treatment process under the COVID-19 pandemic: Performance, mechanisms and implications.

Since the onset of the COVID-19 Pandemic, large amounts of chlorine-containing disinfectants have been used to interrupt the spread of SARS-CoV-2 and residual chlorine eventually entered the hospital or municipal sewage treatment facilities. However, little is known about the effect of chlorine influx on the biological sewage treatment process. Here we investigated the effect of chlorine on the microbiome and the mechanism of microbial chlorine resistance in the activated sludge of the aerobic treatment process, using metagenomic and metatranscriptomic sequencing. We found that chlorine could negatively impact the aerobic treatment performance regarding nitrogen/COD removal with a dose-dependent effect, and the dual effects of chlorine dose and interaction time differentiated the microbial community in activated sludge. The decline of nitrogen/COD removal was attributed to the compressed activity of functional microorganisms, such as the ammonia oxidation bacteria, under chlorinated conditions, and the damage cannot be recovered in a short term. In addition, some microorganisms could survive in chlorinated conditions by up-regulating the chlorine resistance genes (CRGs) expression (approximately 1.5 times) and stimulating new CRGs expression. In particular, species Acinetobacter johnsonii could resist high concentrations of chlorine through various mechanisms, especially the overexpression of efflux pump function encoded by qac genes play a key role. Based on these results, considering the persistence of the epidemic and extensive use of chlorine disinfectants, it cannot be ignored that large amounts of residual chlorine are entering the biological treatment facility, and strictly de-chlorination measures or microbial chlorine resistance regulations before entering should be implemented.

The active synergetic microbiota with Aspergillus as the core dominates the metabolic network of ester synthesis in medium-high temperature Daqu.

The active ester-synthesis microorganisms in medium-high temperature Daqu (MHT-Daqu) largely impact the strong-flavor Baijiu quality, while their actual composition and metabolic mechanism remain unclear. Here, to explore how the active microbiota contributes to MHT-Daqu ester biosynthesis, metatranscriptomic and metaproteomic analyses coupled with experimental verification were performed. The results showed that the MHT-Daqu microbiota with the higher ester-forming ability exhibited a more active dynamic alteration from transcription to translation. The genera Aspergillus, Bacillus, Leuconostoc, and Pediococcus could transcribe and translate obviously more ester-forming enzymes. In the ester-synthesis metabolic network, the synergetic microbiota confirmed by interaction analysis, containing Eurotiales, Bacillales, and Saccharomycetales, played an essential role, in which the Eurotiales and its representative genus Aspergillus contributed the highest transcript and protein abundance in almost every metabolic process, respectively. The recombined fermentation verified that their corresponding genera could produce the ester and precursor profiles very close to that of the original MHT-Daqu active microbiota, while the microbiota without Aspergillus caused a polar separation. These results indicated that the synergetic microbiota with Aspergillus as the core dominated the metabolic network of ester synthesis in MHT-Daqu. Our study provides a detailed framework of the association between the active synergetic microbiota and ester synthesis in MHT-Daqu.

Functional gene transcription variation in bacterial metatranscriptomes in large freshwater Lake Ecosystems: Implications for ecosystem and human health.

Little is known regarding the temporal and spatial functional variation of freshwater bacterial community (BC) under non-bloom conditions, especially in winter. To address this, we used metatranscriptomics to assess bacterial gene transcription variation among three sites across three seasons. Our metatranscriptome data for freshwater BCs at three public beaches (Ontario, Canada) sampled in the winter (no ice), summer and fall (2019) showed relatively little spatial, but a strong temporal variation. Our data showed high transcriptional activity in summer and fall but surprisingly, 89% of the KEGG pathway genes and 60% of the selected candidate genes (52 genes) associated with physiological and ecological activity were still active in freezing temperatures (winter). Our data also supported the possibility of an adaptively flexible gene expression response of the freshwater BC to low temperature conditions (winter). Only 32% of the bacterial genera detected in the samples were active, indicating that the majority of detected taxa were non-active (dormant). We also identified high seasonal variation in the abundance and activity of taxa associated with health risks (i.e., Cyanobacteria and waterborne bacterial pathogens). This study provides a baseline for further characterization of freshwater BCs, health-related microbial activity/dormancy and the main drivers of their functional variation (such as rapid human-induced environmental change and climate change).

Metatranscriptomic analysis revealed Prevotella as a potential biomarker of oropharyngeal microbiomes in SARS-CoV-2 infection.

Background and objectives: Disease severity and prognosis of coronavirus disease 2019 (COVID-19) disease with other viral infections can be affected by the oropharyngeal microbiome. However, limited research had been carried out to uncover how these diseases are differentially affected by the oropharyngeal microbiome of the patient. Here, we aimed to explore the characteristics of the oropharyngeal microbiota of COVID-19 patients and compare them with those of patients with similar symptoms. Methods: COVID-19 was diagnosed in patients through the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by quantitative reverse transcription polymerase chain reaction (RT-qPCR). Characterization of the oropharyngeal microbiome was performed by metatranscriptomic sequencing analyses of oropharyngeal swab specimens from 144 COVID-19 patients, 100 patients infected with other viruses, and 40 healthy volunteers. Results: The oropharyngeal microbiome diversity in patients with SARS-CoV-2 infection was different from that of patients with other infections. Prevotella and Aspergillus could play a role in the differentiation between patients with SARS-CoV-2 infection and patients with other infections. Prevotella could also influence the prognosis of COVID-19 through a mechanism that potentially involved the sphingolipid metabolism regulation pathway. Conclusion: The oropharyngeal microbiome characterization was different between SARS-CoV-2 infection and infections caused by other viruses. Prevotella could act as a biomarker for COVID-19 diagnosis and of host immune response evaluation in SARS-CoV-2 infection. In addition, the cross-talk among Prevotella, SARS-CoV-2, and sphingolipid metabolism pathways could provide a basis for the precise diagnosis, prevention, control, and treatment of COVID-19.

Novel Gene Clusters for Natural Product Synthesis Are Abundant in the Mangrove Swamp Microbiome.

Natural microbial communities produce a diverse array of secondary metabolites with ecologically and biotechnologically relevant activities. Some of them have been used clinically as drugs, and their production pathways have been identified in a few culturable microorganisms. However, since the vast majority of microorganisms in nature have not been cultured, identifying the synthetic pathways of these metabolites and tracking their hosts remain a challenge. The microbial biosynthetic potential of mangrove swamps remains largely unknown. Here, we examined the diversity and novelty of biosynthetic gene clusters in dominant microbial populations in mangrove wetlands by mining 809 newly reconstructed draft genomes and probing the activities and products of these clusters by using metatranscriptomic and metabolomic techniques. A total of 3,740 biosynthetic gene clusters were identified from these genomes, including 1,065 polyketide and nonribosomal peptide gene clusters, 86% of which showed no similarity to known clusters in the Minimum Information about a Biosynthetic Gene Cluster (MIBiG) repository. Of these gene clusters, 59% were harbored by new species or lineages of Desulfobacterota-related phyla and Chloroflexota, whose members are highly abundant in mangrove wetlands and for which few synthetic natural products have been reported. Metatranscriptomics revealed that most of the identified gene clusters were active in field and microcosm samples. Untargeted metabolomics was also used to identify metabolites from the sediment enrichments, and 98% of the mass spectra generated were unrecognizable, further supporting the novelty of these biosynthetic gene clusters. Our study taps into a corner of the microbial metabolite reservoir in mangrove swamps, providing clues for the discovery of new compounds with valuable activities. IMPORTANCE At present, the majority of known clinical drugs originated from cultivated species of a few bacterial lineages. It is vital for the development of new pharmaceuticals to explore the biosynthetic potential of naturally uncultivable microorganisms using new techniques. Based on the large numbers of genomes reconstructed from mangrove wetlands, we identified abundant and diverse biosynthetic gene clusters in previously unsuspected phylogenetic groups. These gene clusters exhibited a variety of organizational architectures, especially for nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS), implying the presence of new compounds with valuable activities in the mangrove swamp microbiome.

Skin infectome of patients with a tick bite history.

Introduction: Ticks are the most important obligate blood-feeding vectors of human pathogens. With the advance of high-throughput sequencing, more and more bacterial community and virome in tick has been reported, which seems to pose a great threat to people. Methods: A total of 14 skin specimens collected from tick-bite patients with mild to severe symptoms were analyzed through meta-transcriptomic sequencings. Results: Four bacteria genera were both detected in the skins and ticks, including Pseudomonas, Acinetobacter, Corynebacterium and Propionibacterium, and three tick-associated viruses, Jingmen tick virus (JMTV), Bole tick virus 4 (BLTV4) and Deer tick mononegavirales-like virus (DTMV) were identified in the skin samples. Except of known pathogens such as pathogenic rickettsia, Coxiella burnetii and JMTV, we suggest Roseomonas cervicalis and BLTV4 as potential new agents amplified in the skins and then disseminated into the blood. As early as 1 day after a tick-bite, these pathogens can transmit to skins and at most four ones can co-infect in skins. Discussion: Advances in sequencing technologies have revealed that the diversity of tick microbiome and virome goes far beyond our previous understanding. This report not only identifies three new potential pathogens in humans but also shows that the skin barrier is vital in preventing horizontal transmissions of tick-associated bacteria or virus communities to the host. It is the first research on patients' skin infectome after a tick bite and demonstrates that more attention should be paid to the cutaneous response to prevent tick-borne illness.