Intestinal Epithelial Cell Exosome Launches IL-1β-Mediated Neuron Injury in Sepsis-Associated Encephalopathy

BackgroundGut–microbiota–brain axis links the relationship between intestinal microbiota and sepsis-associated encephalopathy (SAE). However, the key mediators between them remain unclear.MethodsMemory test was determined by Water maze. Intestinal flora was measured by 16S RNA sequencing. Neurotransmitter was detected by high-performance liquid chromatography (HPLC). Histopathology was determined by H&E, immunofluorescence (IF), and terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) staining. Flow cytometry was employed to determine the proportion of macrophages.ResultsFecal microbiota transplantation (FMT) relieved hippocampus impairment of SAE rats by inhibiting inflammation cytokine secretion, the expression of IBA-1 and neurotransmitter disturbance, and cell apoptosis and autophagy, accompanied by the reduced M1 polarization and M1 pro-inflammation factors produced by macrophages in mesenteric lymph nodes (MLNs). Actually, M1 polarization in SAE rats depended on intestinal epithelial cell (IEC)-derived exosome. GW4869-initiated inhibition of exosome secretion notably abolished M1 polarization and the secretion of IL-1β. However, GW4869-mediated improvement of hippocampus impairment was counteracted by the delivery of recombinant interleukin (IL)-1β to hippocampus. Mechanistically, IEC-derived exosome induced the excessive circulating IL-1β produced by CP-R048 macrophages, which subsequently induced damage and apoptosis of hippocampal neurons H19-7 in an autophagy-dependent manner. And reactivation of autophagy facilitates intestinal IL-1β-mediated hippocampal neuron injury.ConclusionCollectively, intestinal flora disturbance induced the exosome release of IECs, which subsequently caused M1 polarization in MLNs and the accumulation of circulating IL-1β. Circulating IL-1β promoted the damage and apoptosis of neurons in an autophagy-dependent manner. Possibly, targeting intestinal flora or IEC-derived exosome contributes to the treatment of SAE.

A Summer of Cyanobacterial Blooms in Belgian Waterbodies: Microcystin Quantification and Molecular Characterizations

In the context of increasing occurrences of toxic cyanobacterial blooms worldwide, their monitoring in Belgium is currently performed by regional environmental agencies (in two of three regions) using different protocols and is restricted to some selected recreational ponds and lakes. Therefore, a global assessment based on the comparison of existing datasets is not possible. For this study, 79 water samples from a monitoring of five lakes in Wallonia and occasional blooms in Flanders and Brussels, including a canal, were analyzed. A Liquid Chromatography with tandem mass spectrometry (LC-MS/MS) method allowed to detect and quantify eight microcystin congeners. The mcyE gene was detected using PCR, while dominant cyanobacterial species were identified using 16S RNA amplification and direct sequencing. The cyanobacterial diversity for two water samples was characterized with amplicon sequencing. Microcystins were detected above limit of quantification (LOQ) in 68 water samples, and the World Health Organization (WHO) recommended guideline value for microcystins in recreational water (24 µg L−1) was surpassed in 18 samples. The microcystin concentrations ranged from 0.11 µg L−1 to 2798.81 µg L−1 total microcystin. For 45 samples, the dominance of the genera Microcystis sp., Dolichospermum sp., Aphanizomenon sp., Cyanobium/Synechococcus sp., Planktothrix sp., Romeria sp., Cyanodictyon sp., and Phormidium sp. was shown. Moreover, the mcyE gene was detected in 75.71% of all the water samples.

Wolbachia Detection in Field-Collected Mosquitoes from Cameroon

Wolbachia spp., known to be maternally inherited intracellular bacteria, are widespread among arthropods, including mosquitoes. Our study assessed the presence and prevalence of Wolbachia infection in wild mosquitoes collected in Cameroon, using the combination of 23s rRNA Anaplasmatacea and 16s rRNA Wolbachia genes. Mosquitoes that were positive for Wolbachia were sequenced for subsequent phylogenetic analysis. Out of a total of 1740 individual mosquitoes belonging to 22 species and five genera screened, 33 mosquitoes (1.87%) belonging to eight species (namely, Aedes albopictus, A. contigus, Culex quinquefasciatus, C. perfuscus, C. wigglesworthi, C. duttoni, Anopheles paludis and Coquillettidia sp.) were found to be positive for Wolbachia infections. Wolbachia spp. were absent in A. gambiae and A. aegypti, the main vectors of malaria and dengue, respectively. Phylogenetic analysis of the 16S RNA sequences showed they belong mainly to two distinct subgroups (A and B). This study reports the presence of Wolbachia in about eight species of mosquitoes in Cameroon and suggests that future characterisation of the strains is needed.

Klebseilla Oxytoca; An Efficient Pyrene-Degrading Bacterial Strain Isolated from Petroleum Contaminated Soil

Polycyclic aromatic hydrocarbons (PAHs) are the hazardous xenobiotic agents of oil production. One of the methods to eliminate hazardous compounds is bioremediation, which is the most efficient and cost-effective method to eliminate the harmful byproducts of crude petroleum processing. In this study, five pure bacterial isolates were isolated from petroleum-contaminated soil, four of which showed a robust growth on pyrene as a sole carbon source. Various methods viz mass spectroscopy, biochemical assays, and 16s RNA sequencing employed to identify the isolates ascertained the consistent identification of Klebsiella oxytoca by all three methods. Scanning electron microscopy and Gram staining further demonstrated the characterization of the K. oxytoca. High-performance liquid chromatography of the culture supernatant of K. oxytoca grown in pyrene containing media showed that the cells started utilizing pyrene from the 6th day onwards and by the 14th day of growth 3/4th of the pyrene was completely degraded. Genome search for the genes predicted to be involved in pyrene degradation using Kyoto Encyclopedia of Genes and Genomes (KEGG) confirmed their presence in the genome of K. oxytoca. These results suggest that K. oxtoca would be a suitable candidate for removing soil aromatic hydrocarbons.

Anticolonization of Carbapenem-Resistant Klebsiella pneumoniae by Lactobacillus plantarum LP1812 Through Accumulated Acetic Acid in Mice Intestinal

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is highly prevalent and poses a significant threat to public health. In critically ill patients, gut colonization is considered to be the reservoir of recurrent CRKP infection. Therefore, eliminating CRKP carriage in the intestine is critical for preventing subsequent CRKP infection. In the present study, Lactobacillus plantarum LP1812, a probiotic that can inhibit CRKP in vitro, was used as a candidate probiotic to investigate its efficacy for CRKP anticolonization. Compared with the control, mice fed with 1×10 8 CFU L. plantarum LP1812 exhibited significant CRKP clearance from 1×10 4 CFU/mg to less than 10 CFU/mg in mice feces. Furthermore, 16S RNA gene sequencing revealed that L. plantarum LP1812 modulated mice microbiota by increasing the relative abundance of the genus Halomanas, Blautia, and Holdemania. Further KEGG pathway enrichment analysis revealed that fatty acid-utilizing bacteria, such as acetate-producing Bacteroidetes and Blautia flourished in mice fed with L. plantarum LP1812. Moreover, we found that the concentration of acetic acid was higher in L. plantarum LP1812, which inhibited the growth of K. pneumoniae strains in vitro. Meanwhile, mice intragastrically administered with acetic acid exhibited significantly increased CRKP elimination in vivo. In conclusion, L. plantarum LP1812 is a potential candidate for intestinal CRKP anticolonization by regulating the intestinal microbiota and inhibiting CRKP via increased acetic acid in the intestinal lumen.

PROSPECTS FOR USING PSEUDOMONAS ZHAODONGENSIS TO MITIGATE HERBICIDAL STRESS IN WHEAT

The proliferation of herbicide-resistant forms of weeds provokes herbicide application in higher doses. It may have a negative impact on agricultural crops, causing oxidative stress, inhibiting the growth of plants, reducing yield potential. An important task is to find methods to mitigate herbicidal stress in crops. One approach may be to treat crops with microorganisms that favorably affect the growth of plants. Under the conditions of the light site, two-week wheat plants were sprayed with herbicides Octapon estra (0.1 µl/plant) based on 2,4-D and Nanomet (1.3 µg/plant) based on metsulfuron-methyl and a culture of bacteria 12N1 (107 CFU/plant). Herbicide-resistant strain 12N1, previously isolated from soil from the territory of a chemical industry enterprise (Republic of Bashkortostan, Russia), showed nitrogenase activity of 10.1 nmol C2H4•h-1•ml-1.The use of bacteria stimulated the growth of wheat roots both in the variants of the experiment with and without herbicides. Treatment with bacterial culture reduced the proline content in wheat leaves by 1.9 times against the background of the herbicide Octapon extra and by 6.6 times against the background of Nanomet, as well as the return of the total chlorophyll content to the control values. On the basis of the obtained data, the bacterial strain 12N1 was recognized as a potential antidote for mitigating herbicidal stress in wheat and was identified as member of the species Pseudomonas zhaodongensis based on the cultural, morphological, physiological, biochemical features and the sequence of the 16S RNA gene.

Probiotic Characterization And Safety Assessment of Lactococcus Lactis Subsp. Lactis R7 Isolated From Ricotta Cheese

The aim of this study was to identify and characterize in vitro Lactococcus lactis R7 isolated from commercial ricotta cheese. The results from phenotypic characterization demonstrated that L. lactis R7 had growth potential in a wide temperature range (15 °C and 45 °C), ability to tolerate high osmotic concentrations (sodium chloride 4.0 %), ability to growth in acidic and alkaline condition (pH 2.0 and 9.6), and ability to sugar fermentation (glucose, maltose and ribose). The findings confirm that L. lactis R7 belong to the genus Lactococcus. The results from molecular identification by 16S RNA identified the isolate as Lactococcus lactis subsp. lactis R7. The phenotypic characteristics combined with the molecular identification, indicate that the isolate R7 belongs to the lactis subspecies. The isolate L. lactis R7 was tolerant to acidity and bile salts. In the intestinal tract, cell concentrations were higher than 7.98 log CFU.mL-1 in the presence and absence of bile salts. L. lactis R7 showed antioxidant and inhibitory capacity for lipid peroxidation. It also demonstrated capacity for self-aggregation (25.8%), coaggregation (18.3%) and hydrophobicity (11.1%). The antagonist activity of the isolate was greater against Staphylococcus aureus (12.2 mm), when compared to Escherichia coli (11.1 mm) and Salmonella enteritidis (9.5 mm). In the MTT assays, L. lactis R7 did not show cytotoxicity to VERO cells at the evaluated concentrations. In conclusion, L. lactis R7 isolated from ricotta cheese presented probiotic characteristics and compatible safety aspects for use as a food technology culture.

Bovine Visceral Schistosomosis Caused By Schistosoma Indicum in Migrant Cattle Slaughtered at Chennai City, Southern India

One hundred and eighty mesentery samples of cattle were collected during a period of October 2019- March 2020 for screening visceral schistosomosis from Perambur slaughter house, Chennai, Tamil Nadu, India. Schistosoma indicum was identified in eleven mesenteries of Nellore breed of cattle based on morphology and worm number varied from 1-114 per mesentry. Molecular confirmation based on 16s RNA revealed it to be S. indicum. It was found that the infection of S. indicum in cattle was first report in Tamil Nadu in last two decades. The slaughtered cattle originated from neighboring states especially Andhrapradesh. The tract of infection needs to be traced accordingly for future control strategies. Awareness must be created among the livestock farmers to prevent production loss due to S. indicum infection while purchasing cattle from neighboring states within India.

Gut Microbiota and SCFAs Play Key Roles in QingFei Yin Recipe Anti-Streptococcal Pneumonia Effects

Emerging evidence has revealed the presence in animals of a bidirectional regulatory “lung-gut axis” that provides resistance to respiratory infections. Clues to the existence of this system stem from observations that respiratory infections are often accompanied by gastrointestinal symptoms, whereby intestinal microbiota appear to play pivotal roles in combating pathogenic infections. Importantly, short-chain fatty acids (SCFAs) produced by the gut microbiota appear to serve as the biological link between host immune defenses and gut flora. Streptococcus pneumoniae (S.pn), the main cause of lower respiratory tract infections, is involved in more than 1.189 million deaths per year. QingFei Yin (QFY) is known for its excellent therapeutic efficacy in combating bacterial lung infections. In this study, effects of S.pn infection on gut homeostasis were assessed using 16S RNA-based microbiota community profiling analysis. In addition, potential mechanisms underlying QFY recipe beneficial therapeutic effects against bacterial pneumonia were explored using S.pn-infected gut microbiota-depleted mice. Results of data analysis indicated that QFY treatment alleviated lung infection-associated pathogenic processes, while also promoting repair of disordered gut flora and counteracting S.pn infection-associated decreases in levels of SCFAs, particularly of acetate and butyrate. Mechanistically, QFY treatment suppressed inflammatory lung injury through inhibition of the host NF-κB-NLRP3 pathway. These results inspired us to identify precise QFY targets and mechanisms underlying QFY anti-inflammatory effects. In addition, we conducted an in-depth evaluation of QFY as a potential treatment for bacterial pneumonia.

Distinctive Gut Microbiota Alteration Is Associated with Poststroke Functional Recovery: Results from a Prospective Cohort Study

Objectives. Functional prognosis is potentially correlated with gut microbiota alterations following the dysregulation of the gut-microbiota-brain axis after stroke. This study was designed to explore the poststroke alterations of gut microbiota and potential correlations between gut microbiota and global functions. Methods. A total of thirty-eight patients with stroke and thirty-five healthy demographics-matched controls were recruited. Their fecal DNAs were extracted, and the V3-V4 regions of the conserved bacterial 16S RNA were amplified and sequenced on the Illumina MiSeq platform. Microbial composition, diversity indices, and species cooccurrence were compared between groups. Random forest and receiver operating characteristic analysis were used to identify potential diagnostic biomarkers. Relationships between discriminant bacteria and poststroke functional outcomes were estimated. Results. Higher alpha diversity of gut microbiota was observed in poststroke patients as compared to the healthy controls ( p < 0.05 ). Beta diversity showed that microbiota composition in the poststroke group was significantly different from that in the control group. Relative abundance of nine genera increased significantly in poststroke patients, while 82 genera significantly decreased ( p < 0.05 ). The accuracy, specificity, and susceptibility of the optimal model consisted of the top 10 discriminant species were 93%, 100%, and 86%, respectively. Subgroup analysis showed that bacterial taxa abundant between subacute and chronic stroke patients were overall different ( p < 0.05 ). The modified Rankin scale (mRS) ( r = − 0.370 , p < 0.05 ), Fugl-Meyer assessment (FMA) score ( r = 0.364 , p < 0.05 ), water swallow test (WST) ( r = 0.340 , p < 0.05 ), and Barthel index (BI) ( r = 0.349 , p < 0.05 ) were significantly associated with alterations of distinctive gut microbiota. Conclusions. The gut microbiota in patients with stroke was significantly changed in terms of richness and composition. Significant associations were detected between alterations of distinctive gut microbiota and global functional prognosis. It would facilitate novel treatment target selection in the context of stroke while the causal relationships between distinctive gut microbiota alterations and functional variations need to be further verified with well-designed studies.