Frontiers in Microbiology最新文献

[This corrects the article DOI: 10.3389/fmicb.2024.1448675.].

Herpes simplex virus type I (HSV-1) infection-induced host transcript ion shutdown is one of the most critical hallmarks of viral lytic infection. However, how HSV-1 and which viral factors accomplish this dramatic effect is not well understood. In this study, we show that ICP22-defined condensates shutdown host global transcription but facilitate viral transcription. This is independent of its effects on viral infection-triggered changes in splicing, readthrough, and read-in events. ICP22 condensates depleted the serine-2 phosphorylated RNA polymerase II (RNAPII Ser-2P) occupancy from the host transcription start site (TSS), resulting in decreased host transcripts output. At the same time, it ensures proper RNAPII Ser-2P distribution on the viral genome to promote viral transcription. This effect is dependent solely on the condensate-forming activity, as condensate-disrupting point mutations abolish it. In addition, ectopic expressed ICP22 alone could decrease host transcription activity and increase histone H3K27me3 modification level. Thus, ICP22 condensates shut down host transcription by reducing RNAPII binding to host TSS to impair the host transcription.

The non-structural protein 4 (NSP4) of porcine reproductive and respiratory syndrome virus (PRRSV) is equipped with 3C-like serine protease (3CLSP) activity, influencing crucial aspects such as virus replication, host IFN-β suppression, host cell apoptosis induction, and PRRSV detection facilitation. In response to wild or attenuated PRRSV strains, antibodies against non-structural proteins are generated, while inactivated vaccines fail to elicit such responses. Employing the Enzyme-Linked Immunosorbent Assay (ELISA) method targeting non-structural proteins helps discern the immune effects of inactivated versus wild or attenuated vaccine strains. The study focused on the NSP4 protein from the PRRSV XH-GD strain (GenBank No. EU624117.1), which was cloned, expressed, and leveraged as a coating protein for establishing an indirect enzyme-linked immunosorbent assay (ELISA) detection method. This method showcased outstanding specificity, repeatability, and sensitivity, exhibiting a notable agreement rate of 91.74% with the PRRSV IDEXX ELISA kit. The successful development of the NSP4 indirect ELISA not only supports the detection of PRRSV antibodies but also provides a robust platform for ongoing antibody monitoring in pig farming. Utilizing PRRSV NSP4 for ELISA antibody detection offers a more sustainable approach for continuous surveillance. The high agreement between this method and commercial kits lays a solid groundwork for effectively differentiating between inactivated and attenuated vaccines, enhancing the management and monitoring of PRRSV in pig populations.

This study aimed to investigate the effects of rumen-protected guanidinoacetic acid (RP-GAA) on growth performance, gut microbiota, and serum metabolism in beef cattle under chronic heat stress. A randomized block design was employed to allocate 14 F1 Simmental crossbred cattle (Simmental ♂ × Bos indicus ♀) with an average body weight of 312.5 ± 55.0 kg into two groups (n = 7): a control group was fed a basal diet without RP-GAA and a treatment group was fed the same basal diet supplemented with 10.0 g/day of RP-GAA. During feeding experiments, at 2 p.m., the average temperature increased to 31.5°C, with a relative humidity of 69.5% and a THI of 83.2. All animals are under chronic heat stress. The results indicated that RP-GAA supplementation significantly increased dry matter intake and feed conversion ratio in beef cattle under chronic heat stress (p < 0.05). RP-GAA supplementation tended to reduce respiratory rate or rectal temperature (p < 0.1). Compared to the control group, the treatment group exhibited significantly higher glucose, blood urea nitrogen, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol levels (p < 0.05). 16S rRNA gene sequencing revealed that RP-GAA supplementation significantly altered the ruminal microbiota composition, increasing the abundance of Firmicutes and Bacteroidota (p < 0.05), while reducing Proteobacteria (p < 0.01). Principal coordinate analysis (PCoA) and Adonis test (R ² = 0.190, p = 0.003) jointly revealed a distinct difference in fecal microbiota structures between the two groups. Metabolomic analysis identified significant changes in pathways related to creatine synthesis, energy metabolism, and nitrogen utilization, supported by the orthogonal partial least squares discriminant analysis model (R ² Y = 0.983, Q ² = 0.836, p < 0.05). These findings suggest that RP-GAAenhances energy homeostasis, supports gut health, and mitigates the adverse effects of heat stress, providing a promising strategy to improve production efficiency and animal welfare in heat-stressed cattle.

Introduction: Phosphate mining wasteland is contaminated with heavy metals, such as lead (Pb) and cadmium (Cd), which pose significant environmental risks. Ecological restoration of these lands is crucial, but limited research has focused on the remediation of heavy metal-contaminated soils using modified biochar and functional microorganisms.

Methods: In this study, we investigated the bioremediation of phosphate mining wasteland soil using modified biochar in combination with the phosphate-solubilizing bacterium Bacillus cereus. The effects of this synergistic approach on soil nutrient content, heavy metal immobilization, and microbial community structure were assessed.

Results and discussion: The results indicated that the available phosphate content in the soil increased by 59.32%. The content of extractable state Pb^{2 +} and Cd^{2 +} decreased by 65.06 and 71.26%, respectively. And the soil nutrient conditions were significantly improved. Synergistic remediation can significantly increase the diversity and abundance of soil microbial communities (p < 0.05). Janibacter, Lysobacter, Ornithinimicrobium, Bacillus, and Salinimicrobium were the main functional flora during soil remediation, with significant correlations for the promotion of Pb^{2 +} and Cd^{2 +} immobilization and the increase of available phosphate and organic matter. ZitB, czcD, zntA, and cmtR are the major heavy metal resistance genes and regulate metabolic pathways to make microbial community function more stable after soil remediation in phosphate mining wasteland.

Introduction: Pediococcus acidilactici CNCM I-4622 (PA) is a homofermentative Gram-positive coccus that produces lactic acid as a major metabolic by-product. However, the potential of PA to improve intestinal function and, as a result, improve production performance and quality in aged laying hens remains unclear. This study aimed to investigate the effects of PA on egg production, egg quality, intestinal health, and cecal microbiota in aged laying hens.

Methods: A total of 180 Lohmann pink laying hens, aged 80 weeks, were randomly assigned to five groups and fed either a basal diet (PA0) or basal diets supplemented with PA at concentrations of 50, 100, 150, and 200 mg/kg (PA50, PA100, PA150, and PA200).

Results: Compared to the PA0 group, PA did not have a significant effect on the production performance of laying hens (p > 0.05). However, the content of diamine oxidase and the expression level of IL-8 mRNA in the PA50, P100, P150, and P200 groups were significantly reduced (p < 0.05). Additionally, the ileal villus height was significantly increased (p < 0.05). The cecal chowder pH and ileal crypt depth were also significantly lower (p < 0.05), while lipase activity in the ileal mucosa of the PA50 group was significantly increased compared to the PA0 group (p < 0.05). Furthermore, the expression of INF-γ and TNF-α mRNA in the jejunal mucosa was significantly down-regulated (p < 0.05), whereas the expression of Claudin mRNA was significantly up-regulated (p < 0.05). Notably, the relative abundance of Bacteroidota, Fusobacteriota, and Fusobacterium in the PA50 group was significantly higher than that in the PA0 group (p < 0.05).

Discussion: Additionally, cecal metabolomic analysis indicated that following the addition of PA, the pathways enriched with differential metabolites were primarily related to arginine and proline metabolism. Therefore, PA has the potential to improve intestinal morphology and flora, mitigate intestinal inflammatory factors, and strengthen intestinal barrier function. These benefits are attributed to the modulation of arginine and proline metabolic pathways, with optimal effects observed at an addition of 50 mg/kg.

Soybean (Glycine max) crops in Bangladesh face significant challenges due to viral diseases, exacerbated by the hot and humid conditions that favor virus and vector proliferation. The emergence of novel or resurgent viruses can jeopardize soybean production because of the difficulties in identifying and characterizing these pathogens. In addition, detecting and characterizing new plant viruses demands considerable resources and commitment. This study examines soybean plants, collected from research fields in Gazipur, Bangladesh, between February 2022 and January 2023, that exhibited green or yellow mosaic, leaf wrinkling, and mild yellowing symptoms. Utilizing high-throughput sequencing, we examined the virome in soybean leaves. Our findings revealed the presence of three RNA viruses-Potyvirus phaseovulgaris (bean common mosaic virus, BCMV), P. phaseoli (bean common mosaic necrosis virus, BCMNV), a novel crinivirus-and one DNA virus, Begomovirus vignaradiataindiaense (mungbean yellow mosaic India virus, MYMIV). This is the first identification of the novel crinivirus, soybean mild yellows Bangladesh virus (SMYBV), in soybean. We assembled four viral genome sequences for phylogenetic analysis. The novel crinivirus is closely related to the criniviruses CCYV, LCV, and PloACV. BCMV and BCMNV exhibited high sequence similarity with a Bangladeshi isolate in the common bean, which indicated the continued spread of BCMV and BCMNV present in Bangladesh. Mixed infections with MYMIV-SMYBV, MYMIV-BCMV-BCMNV, and MYMIV-BCMNV were detected in soybean samples through RT-PCR and PCR.

Background: The prevalence of carbapenem-resistant Enterobacteriaceae (CRE) has emerged as a serious public health problem worldwide, and the data on the fecal carriage of CRE strains in hospitalized children remain limited. This study aimed to investigate the molecular characteristics of intestinal colonization of CRE in hospitalized children in Shandong, China.

Methods: A retrospective study was conducted from August to November 2023. Antimicrobial susceptibility testing was performed by the broth microdilution method. Carbapenemase genes, drug resistance genes, and plasmid replicon types were detected using multiplex real-time PCR and whole-genome sequencing. Multilocus sequence typing (MLST) was used to determine the genetic relationships between strains.

Results: A total of 20 CRE isolates were identified from 432 fecal samples, with a fecal carriage rate of 4.6%. The CRE isolates predominantly consisted of Escherichia coli (E. coli, n = 13) and Klebsiella strains (n = 6). CRE isolates showed a high resistance rate of 90-100% to seven β-lactam antibiotics. Resistance rates for other antibiotics such as trimethoprim-sulfamethoxazole, tetracycline, azithromycin, ciprofloxacin, chloramphenicol, nalidixic acid, and streptomycin were 90, 85, 85, 80, 75, 75, and 75%, respectively. CRE isolates showed low resistance to amikacin (20%), and none of the isolates were resistant to tigecycline. Additionally, the multidrug resistance rate of CRE isolates was 95%. All CRE strains carried sulfonamide antibiotic and β-lactamase resistance genes, of which the most common β-lactamase resistance genes were bla _NDM-1 (n = 9), bla _NDM-5 (n = 7) and bla _OXA-1 (n = 7). Resistance genes to tetracycline and macrolide antibiotics were also widespread among the strains. The study found that IncFIB and IncFII series plasmids were present in 84 and 42% of the CRE strains, respectively. Additionally, Col, IncFIA, IncC, IncHI2, and IncX series plasmids were also detected. MLST analysis revealed diverse sequence types (STs) among CRE isolates, with ST167 being a common ST among E. coli isolates.

Conclusion: This study revealed bla _NDM E. coli were the dominant isolates in fecal samples of hospitalized children in Shandong Province, with a broad multidrug resistance to antibiotics, emphasizing that infection control measures need to be taken to limit the spread of these strains.

Microbial communities in subsurface coastal sediments are highly diverse and play an important role in nutrient cycling. While the major fraction of microorganisms in sandy sediments lives as epipsammon (attached to sand grains), only a small fraction thrives in the interstitial porewaters. So far, little is known about the composition of these free-living microbial communities. In the subsurface of the sandy beach, investigated in this study, we compared the archaeal and bacterial community structures within sediments and corresponding porewaters applying 16S rRNA gene sequencing. We found that the free-living prokaryotes only had a proportion of about 0.2-2.3% of the bulk communities, depending on the pore space. The interstitial microbial communities showed a small overlap with the attached fraction of 4-7% ASVs, and comprised a unique composition of 75-81% ASVs found exclusively in the porewaters. They were more diverse than the respective sediment-attached fraction and showed a much higher archaea-to-bacteria ratio. The archaea were mainly affiliated to Nanoarchaeota of the DPANN superphylum, with a relative abundance up to 50% of the interstitial communities. The bacterial fraction included several species related to the Candidate Phyla Radiation (CPR). Both prokaryotic lineages are known to have small cell sizes, comprising not-yet cultured species with unidentified metabolic functions. Our findings were supported by the investigation of an adjacent tidal flat, showing a similar trend. Thus, our results indicate the presence of distinct interstitial microbial communities in the subsurface of coastal sediments. This natural enrichment of not-yet cultured Nanoarchaeota and members of the CPR provides the opportunity for targeted metagenomic analyses or even isolating members of these groups for further metabolic characterization.