Archives of Microbiology最新文献

Salmon calcitonin is a small peptide hormone synthesised and released by a specialised gland called ultimobranchial gland in fish. This hormone has been used to treat osteoporosis for over 50 years. The aim of this study was to compare the efficacy of five repeats of salmon calcitonin (5sCT) produced in two different hosts (bacteria and fish cell line). The 5sCT gene was synthesised and cloned in prokaryotic (pET32b(+)) and eukaryotic (pcDNA 3.1 + and pGenlenti) vectors. The pET32 b cloned plasmid was transformed into bacterial host BL 21 (DE3) and expression of recombinant 5sCT was induced by IPTG. The 5sCT cloned pcDNA 3.1 and pGenlenti plasmids were transfected using Lipofectamine 3000 in snubnose pompano fin (SPF) cell line. The expression of recombinant 5sCT protein in both hosts was confirmed by Western blot and ELISA using a polyclonal antibody raised against r-5sCT in mice. The results of Western blot and ELISA confirmed the expression of 5sCT protein in E. coli and SPF cells. The purified r-5cST expressed from both hosts was evaluated in mice via intramuscular injection at various dosages, and it was found that it significantly decreased serum calcium levels in mice when compared to normal mice.

Multiple studies have been conducted to investigate the impact of space conditions on human, plant, and microbial life. This research investigated the virulence of spaceflight mutants of the entomopathogenic fungus Purpureocillium lilacinum (HP7, HP36, HP52) and its original strain (SP535) against Tetranychus cinnabarinus as well as examination of the T. cinnabarinus immune response, including alterations in enzyme profiles and microbiome composition post fungal application. Our observations revealed contrasting, time-specific differences in pathogenicity and tissue infection between the ground-based isolate and spaceflight mutant isolates. Analysis of detoxifying and antioxidant enzymes showed a significant reduction in enzyme activities T. cinnabarinus infected with the most virulent spaceflight mutants at 36 h post-fungal infection, compared to ground-based isolates. Additionally, the microbiota was reduced due to a fungal infection, partly due to decreased antioxidant enzyme activities. Our findings indicate that changes in the microbiota of T. cinnabarinus following infection with P. lilacinum (both ground-based and spaceflight mutant isolates) resulted in variations in metabolism and genetic information-related KEGG pathways. This data can help identify potential changes in the host immune system that drive increased virulence after spaceflight mutation.

During recent survey for the investigation of foliar fungi in Kerala, India, a new species of foliicolous hyphomycete, Paramyrothecium kamalii was discovered on living leaves of Matourea azurea (Plantaginaceae) based on morpho-cultural characteristics and multigene (ITS, LSU, cmdA, tub2, and rpb2) phylogenetic analysis; is described, illustrated and discussed. In vitro Pathogenicity tests were performed and confirmed the pathogenic nature of the fungus, thereby fulfilling Koch’s postulates. Phylogenetically, P. kamalii forms a distinct clade, closely related to P. verroridum, P. indicum, and P. roridum. However, it differs morphologically by having longer conidiophores and conidia and lacks setae, unlike the closer species. The identification of P. kamalii as a new foliar pathogen provides critical insights for surveillance and effective control measure of this foliar disease of M. azurea in tropical ecosystems.

Bacteria experience a continual array of environmental stresses, necessitating adaptive mechanisms crucial for their survival. Thermophilic bacteria, such as Thermus thermophilus, face constant environmental challenges, particularly high temperatures, which requires robust adaptive mechanisms for survival. Studying these extremophiles provides valuable insights into the intricate molecular and physiological processes used by extremophiles to adapt and survive in harsh environments. Through meta-analysis of microarray data, we revealed the key genes in T. thermophilus HB8 that respond to various environmental stresses. The analysis revealed 20 differentially expressed genes (DEGs), including 13 upregulated and seven downregulated genes, with a threshold of|log fold change| > 1 and an adjusted p-value < 0.05. Several genes identified as up-regulated in our analysis belonged to the CRISPR-associated protein (Cas) family. To validate these findings, we further evaluated the relative expression levels of TTHB188 (cas1/casA), TTHB189 (cas2/casB), TTHB190 (cas7/casC), TTHB191 (cas5/casD), TTHB192 (cas6/casE), and TTHB193 (cas1e) using RT-qPCR under H₂O₂ and salt stress conditions. The RT-qPCR analysis revealed significant up-regulation of transcripts, casA, casB, casC, casD, casE, and cas1e under salt stress. However, under H₂O₂ stress, only, casA, casB, and casC exhibited substantial increases in expression. Our findings may indicate that the CRISPR-associated proteins significantly impact the adaptive response of T. thermophilus HB8 to various environmental stresses, particularly salt stress, highlighting its significance in extremophile survival and adaptation. This research offers an important understanding of the complex strategies used by extremophiles to survive in challenging conditions.

Rabies is a deadly neurotropic, zoonotic disease with a mortality rate of 100% after symptoms appear. Rabies virus (RABV) is the primary cause of rabies disease in humans, and it mainly spreads via dog bites in developing countries. Over the course of RABV evolution, multiple RABV variants, called clades, have emerged. However, our understanding of these clades is limited, as the only method to identify a clade is sequencing, followed by phylogeny. In this study, we have developed a rapid, PCR-based method for typing two RABV clades. We utilised highly conserved amino acid changes specific to the Arctic and Africa-2 clades of the rabies virus (RABV). A single nucleotide substitution from adenine to thymine at position 178 within the nucleoprotein gene was found to be clade-specific in the Arctic clade. Similarly, adenine at position 638 is a distinctive marker for the Africa-2 clade. The assay demonstrated high specificity and offers the added benefit of PCR-based amplification, enabling virus detection even when viral titers are low. The assay can identify the Arctic clade and Africa-2 clade without sequencing and is highly specific and sensitive. Furthermore, this method can be adapted to detect other RABV clades and a wide range of viruses.

Antibacterial screening of endophytic fungi from Salacia intermedia identified Diaporthe longicolla as a potent strain exhibiting good activity against multidrug-resistant Staphylococcus aureus and Pseudomonas aeruginosa, with an MIC of 39.1 µg/mL. Scale-up fermentation and chromatographic purification of this strain yielded three known compounds, which were cytochalasin J (1), cytochalasin H (2), and dicerandrol C (3), as identified by liquid chromatography – high mass resolution mass spectrometry (LC-HRMS) and nuclear magnetic resonance (NMR) spectroscopy. Among those compounds, dicerandrol C exhibited broad-spectrum antibacterial activity against ATCC and multidrug-resistant strains of Bacillus subtilis, S. aureus, and P. aeruginosa, and multidrug-resistant strains of Klebsiella pneumoniae and Escherichia coli, with MIC values ranging from 1.04 to 33.30 µM. Furthermore, dicerandrol C outperformed tetracycline in antibacterial efficacy against S. aureus ATCC 6538 and methicillin-resistant S. aureus (MRSA) strains (MIC of 1.04 µM). Further antibacterial evaluation showed that cytochalasin J (221.43 µM), cytochalasin H (202.59 µM), and dicerandrol C (tested at its MIC values of 1.04 µM for S. aureus ATCC 6538 and 16.65 µM for P. aeruginosa ATCC 15442) significantly inhibited bacterial biofilm formation. The biofilm inhibition percentages ranged from 61.09 to 78.17% for S. aureus and 41.22–56.83% for P. aeruginosa. In cytotoxicity assays against MCF-7 cells, all three compounds reduced cell viability (48.68–74.50%), with dicerandrol C demonstrating the highest potency. These findings highlight the potential of dicerandrol C as a powerful antibacterial and cytotoxic agent, facilitating further investigations into its therapeutic applications.

Throughout the life cycle of mushrooms, countless spores are released from the fruiting bodies. The spores have significant implications in the food and medicine industries due to pharmacological effects attributed to their bioactive ingredients. Moreover, high concentration of mushroom spores can induce extrinsic allergic reactions in mushroom cultivation workers. Therefore, it is important to study the bioactive ingredients of medicinal mushroom spores and molecular mechanisms of spore formation to develop healthcare products utilizing medicinal mushroom spores and breed sporeless/low- or high-spore-producing strains. This review summarizes the bioactive compounds of mushroom spores, the influence factors and molecular mechanisms of spore formation. Many bioactive compounds extracted from mushroom spores have a wide range of pharmacological activities. Several exogenous factors such as temperature, humidity, light, nutrients, and culture matrix, and endogenous factors such as metabolism-related enzymes activities and expression levels of genes related to sporulation individually or in combination affect the formation, size, and discharge of spores. The future research directions are also discussed for supplying references to analyze the bioactive compounds of spores and the molecular mechanisms of spore formation in mushrooms.

Candida is a commensal fungus of clinical interest that commonly lives in oral cavity and intestine but can become an opportunist microrganism and cause severe infections. A serie of 10 aminochalcones were designed and synthetized to obtain compounds anti-Candida with potent and broad-spectrum activity. The most active compound J34 demonstrated excellent in vitro activity against Candida albicans, Candida tropicalis, Candida parapsilosis, Candida glabrata and Candida krusei with minimum inhibitory concentration between 1.9 and 7.8 µg/mL. The association of aminochalcone J34 with amphotericin B demonstrated synergistic effect against C. albicans, with Fractional Inhibiroty Concentration Index (FICI) value of 0.5. Subinhibitory concentration of J34 inhibited the C. albicans adhesion to human keratinocytes. Treatment with J34 reduced C. albicans biofilm formation, as well as acts on preformed biofilm in concentration-dependent mode. Time-kill curve demonstrated that J34 had fungicidal action after 12 h of treatment. Preliminary mechanism of action study showed J34 interacts with membrane ergosterol but does not act on fungal cell wall of C. albicans. In additon, in vivo studies using Galleria mellonella indicated low toxic effect of chalcone J34 after 72 h of treatment.

Treponema denticola, a bacterium that forms a “red complex” with Porphyromonas gingivalis and Tannerella forsythia, is associated with periodontitis, pulpitis, and other oral infections. The major surface protein (Msp) is a surface glycoprotein with a relatively well-established overall domain structure (N-terminal, central and C-terminal regions) and a controversial tertiary structure. As one of the key virulence factors of T. denticola, Msp is associated with adherence, immune response, and pore formation by the microorganism. It also mediates several pathological changes in histocytes, such as cytoskeleton disruption, neutrophil phagocytosis, and phosphoinositide balance interruption. In addition, the Msp of T. denticola is also an ortholog of the Treponema pallidum repeat (Tpr) proteins and Msp or Msp-like proteins that have been detected in other oral treponeme species. This review will discuss the structure, pathogenicity and homologs of Msp produced by T. denticola, illuminate the controversy regarding the structure and membrane topology of native Msp, explore the potential roles of Msp in the mechanism of T. denticola immune escape and provide an overview of the cytotoxicity and adherence ability of Msp. Further understanding of the structure and functions of Msp will offer new insights that will help promote further investigations of the pathogenic mechanisms of T. denticola and other treponemes, leading to more effective prophylactic or therapeutic treatments for relevant diseases.

Infection with H. pylori (Helicobacter pylori) is the most prevalent human infection worldwide and is strongly associated with many gastrointestinal disorders, including gastric cancer. Endoscopy is mainly used to diagnose H. pylori infection in gastric biopsies. However, this approach is invasive, time-consuming and expensive. On the other hand, serology-based methods can be considered as a non-invasive approach to detecting H. pylori infection. The LFA (lateral flow assay) serves as a rapid point-of-care diagnostic tool. This paper-based platform facilitates the detection and quantification of analytes within human fluids such as blood, serum and urine. Due to ease of production, rapid results, and low costs, LFAs have a wide application in clinical laboratories and hospitals. In this comprehensive review, we examined LFA-based approaches for detection of H. pylori infection from human fluids and compare them with other high-sensitivity methods like ELISA (Enzyme-linked immunosorbent assay). Furthermore, we reviewed methods to elevate LFA sensitivity during H. pylori infection including, CRISPR/Cas system and isothermal amplification approaches. The development and optimization of novel labeling agents such as nanozyme to enhance the performance of LFA devices in detecting H. pylori were reviewed. These innovations aim to improve signal amplification and stability, thereby increasing the diagnostic accuracy of LFA devices. A combination of advances in LFA technology and molecular insight could significantly improve diagnostic accuracy, resulting in a significant improvement in clinical and remote diagnostic accuracy.