Current Microbiology最新文献

Sporadic epidemics of coxsackievirus A4 (CVA4) have been reported worldwide. However, the lack of the whole genome sequence has restricted the study of the gene characterization and evolution of CVA4. In this study, four whole genome sequences and 17 VP1 sequences of CVA4 identified from Linyi, northern China, in summer 2024 were used for genetic characterization and phylogenetic analysis. Four genotypes (A, B, C, and D) and five subgenotypes (C1-C5) were identified based on VP1 sequences. The Linyi CVA4 strains belong to subgenotype C2, which has also been the main prevalent subgenotype in China in recent years. The Linyi CVA4 strains exhibited high homology with the CVA4 prototype strain in the P1 region while exhibited higher homology with some non-CVA4 EV-A strains identified in China, including five CVA2 strains, three CVA5 strains, three CVA6 strains, one CVA8 strain, one CVA12 strain, and one CVA14 strain in the P2 and P3 regions. Recombination analysis of the whole genome sequences of the Linyi CV4 strains revealed that two Linyi CVA4 strains might be recombinants of one Shanghai CVA4 strain (KJ541163) and one Jiangsu CVA2 strain (OL519580). One Linyi CVA4 strain might be a recombinant of one Shandong CVA2 strain (MK967660) and one Shanghai CVA4 strain (KJ541163).

Abies pindrow, a vital conifer in the Kashmir Himalayan forests, faces threats from low regeneration rates, deforestation, grazing, and climate change, highlighting the urgency for restoration efforts. In this context, we investigated the diversity of potential culturable seed endophytes in A. pindrow, assessed their plant growth-promoting (PGP) activities, and their impact on seed germination and seedling growth. We cultured 729 microbial isolates that were resolved into 30 bacterial and 18 fungal species across various phyla. All 48 isolates exhibited various PGP activities. Specifically, all the cultured isolates showed IAA activity with concentrations ranging from 2.07 to 8.453 μg/ml, while ammonia production ranged from 0.936 to 3.436 mM/ml. Only 18 isolates, predominantly fungi, tested positive for phosphate solubilisation. Additionally, 20 isolates exhibited the ability to inhibit the growth of Fusarium oxysporum f.sp. pini. We selected four bacterial and six fungal isolates, which showed positive results for all PGP activities, to evaluate their effects on seed germination and seedling growth. Notably, seed germination rates increased by 750.9% under bacterial and consortium treatments and by 550.45% under fungal treatment. The consortium treatment also led to a 96% increase in needle count, while bacterial treatment enhanced stem length by 55.4%. Furthermore, shoot biomass also showed a significant increase with both bacterial and fungal treatments, underscoring the potential of harnessing seed endophytes to boost A. pindrow seedling health and resilience. This study underscores the crucial role of seed endophytic diversity in enhancing seed germination, seedling growth, and forest restoration efforts.

The fish intestine is a complex ecosystem where microbial communities are dynamic and influenced by various factors. Preservation conditions during field collection can introduce biases affecting the microbiota amplified during sequencing. Therefore, establishing effective, standardized methods for sampling fish intestinal microbiota is crucial. This study used hybrid groupers (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) to examine the effects of six preservation methods: dry ice (1 day), dry ice (1 day) followed by - 80 °C storage (5 days), liquid nitrogen (1 day), liquid nitrogen (1 day) with subsequent - 80 °C storage (5 days), refrigeration at 4 °C (3 days), and freezing at - 20 °C (3 days), with fresh samples as controls. High-throughput 16S rRNA sequencing assessed microbial diversity, community structure, dominant species, and OTU abundance across treatments. Results indicated that dry ice and liquid nitrogen methods, especially with - 80 °C storage, had minimal impact on microbial diversity and structure. Compared to other preservation methods, refrigeration at 4 °C and freezing at - 20 °C may result in suboptimal reproducibility and altered community structure, particularly affecting rare microbial taxa. This study underscores the need for standardized preservation techniques to ensure accurate fish intestinal microbiota analysis and provides a foundation for future research.

Brucella spp. is the bacterium responsible for brucellosis, a zoonotic infection that affects humans. This disease poses significant health challenges and contributes to poverty, particularly in developing countries. This study aimed to assess the seroprevalence, risk factors, and clinical symptoms of human brucellosis within the general population of Multan and Muzaffargarh, Pakistan. A total of 307 blood samples were collected from patients visiting local hospitals in Multan and Muzaffargarh between August 2015 and January 2016. Demographic information, risk factors, and clinical outcomes were documented. Serum samples were initially screened for anti-Brucella antibodies using the Rose Bengal Plate Test, and positive cases were subsequently confirmed through RT-PCR. The chi-square test assessed the link between Brucella positivity and the identified risk factors. The study recorded an overall seroprevalence of 6.8%, with 8.9% in Multan and 4.3% in Muzaffargarh. Genus-specific Brucella detection through RT-PCR confirmed that 20 out of 21 samples were positive. Significant associations with human brucellosis were found for contact with aborted animals (p = 0.032) and consumption of raw milk (p = 0.031), while factors such as age, gender, occupation, urbanicity, and geographical region did not show a significant impact on seropositivity (p > 0.05). Non-specific clinical symptoms were commonly observed among seropositive patients. The findings highlight the significance of close human interaction with infected animals, especially concerning livestock practices and dairy product consumption. The results also emphasize the importance of focusing efforts on raising awareness in risky occupations and developing control programs by healthcare authorities.

Interactions with mycorrhizal fungi are increasingly recognized as crucial ecological factors influencing orchids' distribution and local abundance. While some orchid species interact with multiple fungal partners, others show selectivity in their mycorrhizal associations. Additionally, orchids that share the same habitat often form relationships with different fungal partners, possibly to reduce competition and ensure stable coexistence. However, the direct impact of variations in mycorrhizal partners on seed germination remains largely unknown. We examined how fungal associates' specific identity and origin affect seed germination in Spiranthes spiralis and Serapias orientalis through in situ symbiotic germination experiments. A total of four fungal isolates, Tulasnellaceae and Ceratobasidiaceae were successfully isolated and cultured from S. spiralis and S. orientalis and two additional orchid species  found in the same habitat: Neotinea tridentata and Orchis provincialis. While all fungal strains facilitated the swelling of seed embryos, only the fungal associate, a member of the Ceratobasidiaceae family isolated from N. tridentata, (NT2) was capable of inducing protocorm formation and subsequent seedling growth of S. spiralis seeds. Another fungal associate belonging to the Tulasnellaceae family and isolated from O. provincialis (OP3) supported seed germination up to the seedling stage of S. orientalis seeds. However, the remaining two fungal strains did not support seed germination. We conclude that fungal associates of co-occurring orchids can promote seed germination and seedling growth in S. spiralis and S. orientalis.

Staphylococcus epidermidis (S. epidermidis) live in different human locations and natural environments. For ribotyping S. epidermidis sub-species, 2507 PCR-amplified reads of 16S rRNA genes of S. epidermidis in a public dataset were used for probabilistic sequence analysis. A sequence probability logo (sequence pLogo) as a reference sequence of 16S rRNA genes of S. epidermidis was constructed. Through implementation of Levenshtein Distance algorithm, two 20-base pairs (bp) motifs, commonly present in 2507 PCR-amplified reads, were identified. The top 38 S. epidermidis isolates, which carried 16S rRNA nucleotide domains that were made of different sequences but have high similarity scores to two 20-bp motifs, were found from 11 human, 8 animal, 9 plant and 10 environmental samples, indicating that these two 20-bp motifs were broadly present in diverse S. epidermidis isolates. Thirty-one PCR-amplified reads of 16S rRNA genes, which were currently not in the dataset, were utilized to verify the feasibility of using two 20-bp motifs for ribotyping S. epidermidis sub-species. S. epidermidis S1, S3, but not S2, isolates on the human scalp carried a 20-bp sequence domain with high similarities to a 20-bp motif in the sequence pLogo. The phylogenetic tree showed that S. epidermidis S1, S2 and S3 were not from a single common ancestor. Two newly identified 20-bp motifs here, thus, provided reference nucleotide residues for ribotyping S. epidermidis.

The recent emergence of bile salt hydrolase (BSH) enzyme as a therapeutic target reflects its unbound potential in mitigating hypercholesterolemia, obesity, and gastrointestinal issues. However, to bolster its industrial application, optimization of BSH assay lays the cornerstone for enhancing sensitivity, specificity, and reproducibility. The current study delved into optimizing the BSH assay parameters utilizing response surface methodology (RSM) and one-factor-at-a-time (OFAT) method for two novel, natural BSH producers, Heyndrickxia coagulans ATCC 7050 and Lactiplantibacillus plantarum ATCC 10012. Factors such as pH, temperature, cell concentration, and substrate concentration were optimized using RSM and numerical optimization. The analysis of responses unveiled significant insights into the biochemical characteristics of BSH from both organisms. The optimal pH for BSH activity from H. coagulans ATCC 7050 and L. plantarum ATCC 10012 was determined to be 6.1 and 6.0, with their corresponding optimal temperatures being 60 °C and 40 °C, respectively. Subsequent to RSM, optimization of the remaining parameters such as buffer type, buffer molarity, cells-to-substrate ratio, etc., performed using the classical OFAT approach further enhanced BSH activity, with H. coagulans ATCC 7050 and L. plantarum ATCC 10012 exhibiting a 1.45 and 0.87-fold increase, respectively. Conventionally, even though BSH has been optimized using the OFAT approach, this is the first instance in which a hybrid model using RSM has been applied to achieve a greater performance. These findings offer valuable insights in augmenting the specificity, efficiency, and stability of BSH and broaching new avenues for industrial and therapeutic applications.

Lactic acid bacteria (LAB), traditionally consumed as fermented foods, are now being applied to the medical field beyond health-functional food as probiotics. Therefore, it is necessary to continuously discover and evaluate new strains with suitable probiotic characteristics, mainly focusing on safety. In this study, we isolated eight new strains from postmenopausal vaginal fluid using culturomics approaches, an emerging area of interest. Data showed that most strains possessed significant cell surface hydrophobicity (≥ 76%), auto-aggregation capacity (17 to 61%), strong adhesion activity (8 to 34%), and excellent resistance to gastric acid, bile salt, and digestive enzyme, enhancing their survival in the gastrointestinal tract. Moreover, the strains exhibited functional characteristics, including substantial antibacterial activity with a minimal inhibitory concentration (MIC) ranging from 12.5 to 50%. They also harbored bacteriocins genes, produced short-chain fatty acids (acetate and propionate), exhibited significant phagocytic activity, possessed high antioxidative properties, rapidly depleted sodium nitrite, and exhibited proteolysis and β-glucosidase activity. In addition, heat-killed LAB strains significantly reduced the gene expressions of proinflammatory cytokines such as IL-β, IL-6, and iNOS in macrophages. Safety assessment revealed no cytotoxicity in macrophage cell lines. All strains tested negative for biogenic amine or H₂O₂ production, displayed no gelatinase or hemolytic activity, lacked virulence genes or detrimental enzymes, and displayed antibiotic susceptibility. In summary, these newly isolated strains demonstrate excellent probiotic functionality with a strong focus on safety, making them promising candidates for future drug development in the relevant fields.

Remodelling regulatory pathways to directionally increase the efficiency of specific promoters in chassis cells is an effective strategy for the rational construction of expression systems. However, the repeated utilization of one regulator to modify the host cell to improve expression motif efficiency has a limited effect. Therefore, it is preferable to identify new regulatory factors to activate specific pathways and thus further improve the efficiency of target elements. Heterochromatin protein 1 (HP1) is considered a main factor responsible for heterochromatin maintenance; it binds DNA and thus forms a tight structure to repress gene expression in fungi. This study revealed that the overexpression of HepA (a homologue of HP1) increased amylase expression in Penicillium oxalicum. Furthermore, HepA was overexpressed in two engineered strains in which the endoglucanase TaEG and amylase Amy15B were recombinantly expressed under the control of the amylase promoter Pamy15A, resulting in increased production of these two enzymes. Therefore, HepA could be used as a novel facilitator to modify Penicillium chassis cells, in which the efficiency of expression motifs located in the amylase pathway can be further strengthened.

Brucellosis, a zoonotic disease caused by Brucella spp. globally, is of great significance not only to livestock but also to public health. The most significant of the twelve species is Brucella melitensis. This article is devoted to the endemic region of Iran and aims to uncover the molecular epidemiology of B. melitensis. Biotyping, AMOS-PCR, Bruce-ladder PCR, and the in silico method of MLVA were employed to test 40 B. melitensis isolates from humans, cows, sheep, goats, camels, and horses which are found in thirteen Iranian provinces throughout the years 2015 to 2022. The data from the MLVA-8 analysis showed that there were seven genotypes that could be identified, and the most commonly identified genotype was genotype 63. The data from the MLVA-10 analysis showed that there were seven genotypes, with genotype 213 being the most prevalent in Iran. The data from the MLVA-11 analysis showed that there were eight genotypes, with genotype 111 being the most prevalent in Iran. The MLVA and SNP analysis results showed that the bacteria were grouped into two main groups, known as the Eastern Mediterranean and American groups. Moreover, the outcomes from these analyses have added considerably to our understanding of the genetic/historical relationships among the isolates. Our study indicates a high prevalence of B. melitensis biovar 1 in Iran, accounting for 82.5% of the isolates. The study provides insight into such matters as the complex epidemiology of B. melitensis in Iran, suggesting different ways of transmission and sources of infection. This research points out the vital significance of the continuation of the surveillance and curation of B. melitensis in the diverse species of animals and humans. The simplicity and efficiency of MLVA-based molecular epidemiology offer information on the geographic distribution and genetic diversity of B. melitensis and, therefore, help in the devising of targeted strategies for the prevention of disease in animals.