Dietary supplementation of exopolysaccharides from Lactobacillus rhamnosus GCC-3 improved the resistance of zebrafish against spring viremia of carp virus infection

Spring viremia of carp virus (SVCV) can cause high mortality of fish. The aim of this study was to investigate the effects of Lactobacillus rhamnosus GCC-3 exopolysaccharides (GCC-3 EPS) on zebrafish (Danio rerio) infected with SVCV and elucidate the underlying mechanisms. Zebrafish were fed with a control diet or diet supplemented with 0.5% and 1% of GCC-3 EPS for 2 weeks. The results showed that supplementation of GCC-3 EPS significantly improved the survival rate of zebrafish compared with the control group. In addition, dietary 0.5% and 1% GCC-3 EPS significantly up-regulated the expression of genes related to type I interferon (IFN) antiviral immunity. Consistent with in vivo results, GCC-3 EPS significantly inhibited SVCV replication in zebrafish embryonic fibroblast (ZF4) cells while significantly increased the expression of type I IFN signaling pathway related genes. Furthermore, knocking down TANK-binding kinase 1 significantly blocked the antiviral effect of GCC-3 EPS. Dietary GCC-3 EPS improved gut microbiota, and the culture supernatant of GCC-3 EPS-associated microbiota significantly inhibited SVCV replication in ZF4 cells compared with the control-microbiota counterpart. In conclusion, our results indicate that dietary GCC-3 EPS can improve the resistance of zebrafish against SVCV infection, and the mechanism may involve enhanced type I interferon signaling. KEYW

Effects of nuclease-treated fermentation product of Lactobacillus rhamnosus GCC-3 on growth, hepatic health and gut microbiota of zebrafish (Danio rerio) fed a high-fat diet

Probiotics are reported to improve the nutrition, immunity, and health of fish. Nuclease can hydrolyze nucleic acids of probiotics to produce nucleotides. The present study investigated the effect of stabilized fermentation product of nuclease-treated Lactobacillus rhamnosus GCC-3 (GCC-3 NT) on growth, non-specific immunity, liver health, and gut microbiota of zebrafish (Danio rerio). Compared to the high-fat diet (HFD) group, GCC-3 NT did not affect the growth performance of zebrafish. However, GCC-3 NT treatment can significantly increase the lysozyme activity and the total antioxidant capacity of body surface mucus. In addition, dietary GCC-3 NT significantly reduced the content of hepatic triglycerides (TAG) in zebrafish while significantly increased the expression of acyl-coenzyme A oxidases 3 (ACOX3) and proliferator-activated receptor γ coactivator 1α (PGC1α) compared with the HFD group. The 16S rRNA gene sequencing showed that GCC-3 NT reduced the relative abundance of Actinobacteria while increased Firmicutes at the phylum level. The relative abundance of Rhodococcus was significantly decreased and Lactobacillus and Staphylococcus abundance were significantly increased in the GCC-3 NT group compared to the HFD group. Furthermore, PCoA analysis showed GCC-3 NT diet had a significant effect on the autochthonous microbiota compared to the HFD diet. Together, our results showed that nuclease-treated L. rhamnosus fermentation product can improve the immunity, liver health and gut microbiota of zebrafish, suggesting that it can be potentially used as a functional feed additive for aquaculture

Isolation and Characterization of N-acyl Homoserine Lactone-Producing Bacteria From Cattle Rumen and Swine Intestines

Quorum sensing systems regulate gene expression in response to bacterial population density. Acyl-homoserine lactones are a class of quorum sensing molecules found in cattle rumen that are thought to regulate the gene expression of enterohemorrhagic Escherichia coli and thus help this pathogen survive in animal gastrointestinal tracts. However, the specific bacteria that produce these signaling molecules in bovine and porcine gastrointestinal tracts are unknown. Here we developed methods to concentrate gastrointestinal fluids and screen the bacteria that produce acyl-homoserine lactones. We isolated a Pseudomonas aeruginosa strain YZ1 from cattle rumen, and an Aeromonas hydrophila strain YZ2 from pig intestine. Mass spectrometry analysis of culture supernatants indicated at least three specific classes of acyl-homoserine lactones produced by YZ1, and a C4-acyl-homoserine lactone produced by YZ2. Transformation of E. coli with P. aeruginosa or A. hydrophila luxI homologs,which can produce short- or long-chain acyl-homoserine lactones conferred upon E. coli the ability to synthesize acyl-homoserine lactones and affected gene expression, motility, and acid tolerance of E. coli. This is the first study reporting the isolation and characterization of acyl-homoserine lactone synthase-positive bacteria from cattle rumen and swine intestines

Optimization Plug Mode of External Fuel and Weapons for Less Changing Aircraft Center of Gravity

To achieve the minimum change of aircraft center of gravity, plug mode optimization was carried out. Plug mode, including weight and position of external fuel and weapon load, was selected as design mode. Numerical model for calculating aircraft center of gravity was established and used to generate mode samples. Random search algorithm (RSA) was designed and applied for solving the optimization plug mode, and the precise solution of plug mode was determined by full array method (FAM). Compared with typical plug mode, the optimization mode can reach a minimum change in aircraft center of gravity with fewer samples than the solution by FAM. RSA coupled with FAM is an effective scheme for the optimization of aircraft plug mode

Both flagella and F4 fimbriae from F4ac+ enterotoxigenic Escherichia coli contribute to attachment to IPEC-J2 cells in vitro

The role of flagella in the pathogenesis of F4ac[superscript +] Enterotoxigenic Escherichia coli (ETEC) mediated neonatal and post-weaning diarrhea (PWD) is not currently understood. We targeted the reference C83902 ETEC strain (O8:H19:F4ac[superscript +] LT[superscript +] STa[superscript +] STb[superscript +]), to construct isogenic mutants in the fliC (encoding the major flagellin protein), motA (encoding the flagella motor), and faeG (encoding the major subunit of F4 fimbriae) genes. Both the ΔfliC and ΔfaeG mutants had a reduced ability to adhere to porcine intestinal epithelial IPEC-J2 cells. F4 fimbriae expression was significantly down-regulated after deleting fliC, which revealed that co-regulation exists between flagella and F4 fimbriae. However, there was no difference in adhesion between the ΔmotA mutant and its parent strain. These data demonstrate that both flagella and F4 fimbriae are required for efficient F4ac[superscript +] ETEC adhesion in vitro

Changes in relative peripheral refraction and optical quality in Chinese myopic patients after small incision lenticule extraction surgery.

PurposeTo observe changes in retinal refraction difference values (RDV) and aberrations after small incision lenticule extraction (SMILE) surgery and evaluate their correlations.MethodsThis study recruited 112 patients (112 eyes) who underwent SMILE for myopia. Participants were classified into the Low and Moderate Myopia group (LM, -0.50 to -6.0 D) and High Myopia group (HM, >-6.0 D) according to the central spherical equivalent (SE). RDVs in the five retinal eccentricities from 0° to 10°, 10° to 20°, 20° to 30°, 30° to 40°, and 40° to 53° are recorded as RDV-(0-10), RDV-(10-20), RDV-(20-30), RDV-(30-40), and RDV-(40-53), respectively; additionally, RDVs have four sectors, i.e., RDV-Superior (RDV-S), RDV-Inferior (RDV-I), RDV-Temporal (RDV-T), and RDV-Nasal (RDV-N). With a 3-month follow-up, changes in RDV (ΔRDV) and changes in aberrations [Δtrefoil, Δcoma, Δspherical aberration (SA), and Δtotal higher-order aberrations (HOA)] after surgery were recorded.ResultsNo significant differences were observed in total RDV (TRDV), RDV-(0-53), RDV-S, RDV-I, RDV-N, trefoil, coma, and SA between the two groups before SMILE surgery. However, after SMILE, hyperopic defocus values [TRDV, RDV-(20-53), RDV-S, RDV-T, and RDV-N] in the LM group and hyperopic defocus values [TRDV, RDV-(20-53), RDV-S, and RDV-N] in the HM group were significantly lower at 3 months postoperatively than preoperatively, and the RDV-(40-53), RDV-S, and RDV-N were lower in the HM group than in the LM group. Aberrations [trefoil (vertical), coma, and HOA] in the LM group and aberrations (trefoil, coma, SA, and HOA) in the HM group were significantly higher at 3 months postoperatively than preoperatively, and the coma, trefoil(horizontal), SA, and HOA were higher in the HM group than in the LM group. In the multivariate analysis, ΔRDV-(40-53) was significantly correlated with ΔSA, and ΔRDV-T and ΔRDV-N were significantly correlated with Δcoma (horizontal).ConclusionsOur findings suggest that SMILE reduces retinal peripheral hyperopic defocus but introduces some higher-order aberrations, especially in people with high myopia refractive errors

Escherichia coli type III secretion system 2: a new kind of T3SS?

International audienceType III secretion systems (T3SSs) are employed by Gram-negative bacteria to deliver effector proteins into the cytoplasm of infected host cells. Enteropathogenic Escherichia coli use a T3SS to deliver effector proteins that result in the creation of the attaching and effacing lesions. The genome sequence of the Escherichia coli pathotype O157:H7 revealed the existence of a gene cluster encoding components of a second type III secretion system, the E. coli type III secretion system 2 (ETT2). Researchers have revealed that, although ETT2 may not be a functional secretion system in most (or all) strains, it still plays an important role in bacterial virulence. This article summarizes current knowledge regarding the E. coli ETT2, including its genetic characteristics, prevalence, function, association with virulence, and prospects for future work

Global Research on Cognitive Frailty: A Bibliometric and Visual Analysis of Papers Published during 2013–2021

This study analyzed the current status, hotspots, and emerging trends of global research on cognitive frailty, in order to provide new research ideas for researchers. Articles and reviews related to cognitive frailty, published from 2013 to 2021, were retrieved from the Web of Science Core Collection (WoSCC) database on 26 November 2021. CiteSpace 5.8.R3 was employed for data analyses. A total of 2077 publications were included. There has been a rapid growth of publications on cognitive frailty research since 2016. The United States, Italy, England, and Australia have been the leading research centers of cognitive frailty; however, China has also recently focused on this topic. The National Center for Geriatrics and Gerontology, and Shimada H. were found to be the most prolific institution and author, respectively. Co-citation analysis identified 16 clusters, of which the largest was cognitive frailty. The keywords which occurred most frequently were “older adult”, followed by “cognitive impairment”, “frailty”, “risk”, “dementia”, “prevalence”, “mortality”, “health”, and “Alzheimer’s disease”. Burst keyword detection revealed a rising interest in cognitive frailty models. By analyzing these publications from recent years, this study provides a comprehensive analysis of cognitive frailty research