查看更多>>摘要：Studies on marine epizootics are often based on the identification of a single pathogen. However, the onepathogen-one-disease paradigm is not always sufficient to explain the disease, especially since the evidences on the role of microbiota in health and disease. Vibrio splendidus strains have been associated with Mytilus edulis mortality in France. To assess the role of mussel microbiota in the infectious process, we performed experiments combining the investigation of total microflora dynamics during a realistic experimental infection by V. splendidus and the monitoring of mussel survival and the dominance of potential opportunistic bacteria after antibiotic treatment. We found that Vibrio exposure affected the structure and predictive function of the mussel microbiota. Dysbiosis was accompanied with the appearance of a pathobiont dominated by Bacteroidetes and Fusobacteria phyla. The injection of a homogenate of infected organisms increased Mytilus mortality compared to the direct injection of Vibrio while the antibiotic pretreatment reduced the effect of pathogen exposure and mortalities. The decrease of opportunistic bacteria abundance in antibiotic pretreated animals confirmed their implication in pathogenesis. Our findings suggest that mussel disease results from a collaboration between external pathogens and pathobiont bacteria. Therefore, an insight into microbiota functions is needed to a better understanding of pathosystems.
查看更多>>摘要：New Delhi metallo-13-lactamase-1 (NDM-1) can hydrolyze almost all antibiotics of the 13-lactam group, resulting in the generation of multidrug resistant bacteria. Besides its broad hydrolytic activity, pathogens expressing NDM-1 often harbor other antibiotic-resistant genes, further promoting the pervasion of multi-resistant clinical isolates and making clinically available drugs scantier. Despite the urgent need for NDM-1 inhibitors, there is no approved drug in clinic. Here, we summarize NDM-1 inhibitors developed since 2018, classify these compounds by chemical scaffolds, and propose some inconsistencies and notable problems among these studies, which are expected to benefit future research.
查看更多>>摘要：Soil salinity is one of the major limiting factors of the crop production, it has been constantly increasing in agricultural land due to the impact of climate change and urbanisation. High salinity in the agrolands can lead ionic, oxidative, osmotic and water stress to crops. A potential phosphate solubilising bacterium, Curtobacterium luteum was isolated from marine environment (seagrass meadow) and was evaluated for the enhancement of plant growth promotion of three different agro plants (rice, tomato and chilli) using agro saline soil. The strain C. luteum exhibited efficient phosphate solubilisation in both qualitative (SI-2.88) and quantitative (208.41 mu g/ ml) analysis at optimised conditions. In addition to phosphate solubilisation, it showed numerous valuable traits to promote plant growth such as -production of organic acids (Tartaric and malic acids), phosphatase, phytase (SI-2.9), IAA (4.1 mu g/ml), urease and nitrogen fixation. The bacterium potentially enhances the plant growth under saline stress conditions and exhibited prominent plant growth promotion in all the three plants (rice, tomato and chilli) compared to the control. Also, it enhances the concentration of phosphorous in the soil and balances the soil pH. The present results indicate that the C. luteum can serve as a multifaceted biofertilizer under saline stress condition and be an effective alternative to the toxic chemical phosphate fertilizers that cater to the single purpose of providing phosphorous to plants.
查看更多>>摘要：The emergence of drug-resistant Staphylococcus aureus (S. aureus) has limited drug options for the clinical treatment of S. aureus infections. Considering recent reports, therapeutic strategies targeting bacterial virulence hold great promise, and alpha-hemolysin (encoded by hla), a critical virulence factor of S. aureus, plays a vital role during bacterial infection. Herein, we demonstrated that hispidulin effectively inhibited the hemolytic activity of S. aureus USA300 without suppressing bacterial growth, along with inhibiting hla transcription and expression in a dose-dependent manner. As heptamer formation is essential for hla-mediated invasion of cells, nevertheless, hispidulin did not affect the deoxycholate-induced oligomerization of hla, suggesting that hispidulin did not affect the protein activity of hla. In vitro assays illustrated that hispidulin bound to agrA(C), a crucial protein in quorum sensing. Meanwhile, hispidulin alleviated A549 cell damage caused by S. aureus USA300 and reduced lactate dehydrogenase release. In vivo studies showed that hispidulin had a protective effect against pneumonia caused by S. aureus USA300 in mice. S. aureus did not develop resistance to hispidulin in the short term. Interestingly, our research indicated that hispidulin synergized with the antibacterial activity of cefoxitin. These results showed that hispidulin effectively inhibited alpha-hemolysin expression by inhibiting the agr quorum sensing of S. aureus. It has promise as an agent to treat S. aureus infection.
查看更多>>摘要：The growing interest in low-input agriculture in recent years has focused the use of microbial biofertilizers to improve plant growth and yield through a better mobilization of indigenous source of key nutrients such as nitrogen, phosphorus, potassium etc. In this context, soil microorganisms especially Actinobacteria might play an important role. With their multifunctional activities, they are involved in nutrient cycling, soil quality and crop productivity as well as plant health which make them not only the eco-friendly alternative for agriculture but also for humankind. Bearing this in mind, it is primordial to further explore the special link between these microorganisms and soil -plant ecosystems. Therefore, this review discusses the importance of Actinobacteria as microbial biofertilizers and highlights the future needs and challenges for using them for sustaining crop. The patents and scientific literature analysis from 2000 to 2020 show that 16 patents claiming Actinobacteria as biocontrol or biofertilizer in agriculture and 949 indexed research articles related to Actinobacteria effect on plant growth and phosphate solubilization have been published. Furthermore, Actinobacteria ability to increase growth and yield of staple crops such as wheat maize, tomato, rice, and chickpea plant have been highlighted. Much more effort and progress are expected in the industrial development of actinobacterial bioinoculants as areas such as synthetic biology and nano-biotechnology advance.
查看更多>>摘要：In the past, tumor and microbial infection were commonly regarded as independent diseases with few interrelations. The discovery of bacteria in tumor tissue changed the knowledge of bacteria-tumor relationship. Recently, more and more findings have demonstrated the significant effects of bacteria on the genesis, development and metastasis of tumor. Particularly, the influence of bacteria on tumor immunity is of great interest. Bacteria can inhibit the function of immune system through multiple mechanisms. On the other hand, some bacteria can also enhance the immune response and inhibit tumor progression. Understanding the bacteria-tumor interactions is of great importance for developing novel anticancer approaches. Herein, we aim to provide a comprehensive understanding of the tumor/tumor immunology, the biogenesis of bacteria in tumor and the relation of tumorigenesis with bacteria. In addition, the roles of bacteria in tumor immunology and the potential approaches to use bacteria for cancer therapy are discussed.
查看更多>>摘要：Growing research suggests that endophytic fungi deeply affect plant physiology, development, and metabolism, which has become an indispensable subject in plant research. However, the micromolecular mechanisms remain vague due to the complexity of the interactions. This article summarizes the latest progress in the mechanism studies of the symbiotic relationships between endophytic fungi and plants. We address the aspects from signal generation, plant defense, to fungal coping strategies to establish the balanced constraint relationships between fungi and their hosts that finally form "a community of shared future." These processes do not occur in isolation but in synergy. Both endophytic fungi and their host plants contribute to establishing the stable symbiosis. New insights have been provided into a deeper understanding of the occurrence of species interactions and their applications to solving practical problems.
查看更多>>摘要：Streptococcus suis (S. suis) is an important zoonotic pathogen threatening the global pig farming industry. It causes respiratory and digestive tract infections simultaneously in pigs. The balanced gut microbiota not only affects the local mucosal immune response but also involves the regulation of the immune status of the distant lung tissues that is termed as "gut-lung " axis. Whether S. suis affects the gut during lung infection and how does the intestinal microbial disturbance play role in the development of lung infection during S. suis exposure is not clear yet. Therefore, in the current study, we constructed the animal model using six-week-old mice (N = 48) divided into four groups with S. suis serotype 2 (SS2)-induced lung infection and the antibiotic treated gut microbiota dysbiosis. By means of various techniques (like HE staining, RT-qPCR, Western Blot and ELISA and viability detection) we explored that S. suis can concurrently cause intestinal tissue damage and inflammation after lung infection. Moreover, gut microbiota dysbiosis changes the balance of Th1/Th2 cells that aggravates lung injury during the infection. Thus, "gut-lung " axis of the communication between the gut microbiota and lung infection was established through the spleen and blood. In addition, intestinal dysbacteriosis can affect alveolar macrophage activity for a long time and the balance of gut microbiota plays an important role in lung infection caused by S. suis. Hence, this study clarified the pulmonary infection caused by SS2 from the perspective of the intestinal microbiota providing novel theoretical basis for the treatment of related lung diseases.
查看更多>>摘要：Acinetobacter baumannii (A. baumannii) is an opportunistic pathogen and leading cause of health care-associated infections. Several known pathogenic factors, including lipopolysaccharide, capsular polysaccharides, phospholipase, protein secretion systems, two component efflux pumps and biofilm formation, are associated with the bacteria. However, owing to the new biological characteristics rapidly developed under the external stress, the pathogenesis becomes complicated. The formation of mucoid phenotype is a major adaptive defense response for A. baumannii. The mucus is mainly comprised of capsular polysaccharide, which forms a barrier around the bacterial cell wall, and provides protection from environmental pressures and host immune responses. Importantly, mucoid formation has been shown to confer changes in the pathogenicity and pathogenesis of A. baumannii. Thus, this review aims to highlight the biological characteristics, virulence and underlying pathogenic mechanisms of mucoid A. baumannii. We primarily provide profound insight into the structure, function and detecting methods of the mucus in mucoid A. baumannii. Then we mainly illustrate the current studies on mucoid A. baumannii. Finally, the unsolved areas associated with mucoid A. baumannii are summarized. In summary, this review will critically offer a comprehensive understanding of mucoid A. baumannii and provide novel insight into the diagnosis and intervention strategies for the increasingly deadly human pathogen.
NSTL
Elsevier