Characterization and potential lipid-lowering effects of lactic acid bacteria isolated from cats.

Introduction: This study aimed to study the characterization and the potential lipid-lowering effects of new isolated lactic acid bacteria from the feces of healthy adult cats. Methods: We collected 85 cat fecal samples, isolated, screening lactic acid bacteria strains from samples, and investigated their in vitro and in vivo biological properties. Results: A total of 221 lactic acid bacteria strains were isolated from 85 cat fecal samples. Sixteen strains with calcium dissolution rings greater than 1 mm were identified and selected for further characterization. Three lactic acid bacteria strains, Lactobacillus plantarum L-27-2, Pediococcus lactis L-14-1, and Enterococcus faecium, were identified as showing the most promising rates of cholesterol degradation (greater than 20%) and bacteriostatic radius (over 15 mm). These three strains exhibited robust growth and adherence to epithelial cells, along with adaptability to low pH (greater than 70%) and high bile salt conditions (greater than 60%), and remarkable cholesterol degradation and anti-pathogen activity. Sixteen mice were fed a high-fat diet (HFD) from 4 to 8 weeks of age, while a control group of the same size received a normal diet (ND). At 8 weeks of age, serum, feces and adipose tissue were collected. The results showed that, compared with mice fed an HFD diet alone, all mice fed an HFD diet plus lactic acid bacteria could decrease weight gain. P < 0.05 and the pathological changes of adipose tissue were alleviated. In addition, mice fed L-14-1 and F203 showed abdominal fat accumulation decreased (P < 0.05). Mice fed L-27-2 showed serum and liver triglyceride (TG) decreased (P < 0.05) and mice fed F203 showed serum high density lipoprotein cholesterol (HDL-C) increased (P < 0.01). mice fed L-27-2 and L-14-1 showed inflammatory cytokines (IL-6) was decreased (P < 0.01) Analysis of the fecal microbiota of mice fed these three lactic acid bacteria strains revealed alterations in the gut microbial community. There were common changes in intestinal microbes in mice fed these three lactic acid bacteria: (1) Bacteroides decreased; (2) Myxococcus increased; (3) Lachnoclostridium decreased. The microbes mentioned are all part of the core intestinal flora. Discussion: This study provided three potential lactic acid bacteria for alleviating animal obesity and inflammation.

Novel Label-Free Nanocrystalline Gold Interdigitated Microelectrode Immunosensor for the Rapid and Ultrasensitive Detection of SARS-CoV-2.

Waves of COVID-19 outbreaks have dragged down the global economy and endangered human life. There is an urgent need for timeliness and sensitive SARS-CoV-2 detection techniques to complement the existing PCR assay. Herein, the controllable growth of gold crystalline grains was achieved by applying the reverse current during pulse electrochemical deposition (PED) interval. The proposed method validates the effects of pulse reverse current (PRC) on the atomic arrangement, crystal structures, orientations, and film characteristics in Au PED. The gap between the gold grains on the surface of the nanocrystalline gold interdigitated microelectrodes (NG-IDME) fabricated by the PED+PRC process matches the size of the antiviral antibody. Immunosensors are prepared by binding a large number of antiviral antibodies on the surface of NG-IDME. The NG-IDME immunosensor has a high specific capture ability for SARS-CoV-2 nucleocapsid protein (SARS-CoV-2/N-Pro) and completes ultrasensitive and quantification of SARS-CoV-2/N-Pro in humans and pets within 5 min (the LOQ as low as 75 fg/mL). The specificity, accuracy, stability, and actual blind sample tests show that the NG-IDME immunosensor is suitable for the detection of SARS-CoV-2 in humans and animals. This approach assists in monitoring the transmission of SARS-CoV-2-infected animals to humans.

Progesterone Promotes In Vitro Maturation of Domestic Dog Oocytes Leading to Successful Live Births.

Gene-edited dogs are promising models for biomedical research because they have hundreds of genetic diseases that are similar to humans. A common method for producing gene-edited dogs is assisted reproductive technology (ART) using in vivo oocytes or embryos, but it is much more inefficient and has a higher cost. ART for dogs has lagged mostly because of the lack of an efficient in vitro maturation system. Because early maturation of canine oocytes occurs in follicles with extremely high concentrations of progesterone (P4), we hypothesize that P4 has an important role during maturation. In this study, we obtained ovaries of female dogs and collected cumulus−oocyte complexes, which were cultured in vitro in microdrops containing different P4 concentrations (0, 10, 40, 100 or 200 µg/mL). We found that 40 µg/mL P4 produced the highest oocyte maturation rate (29.7% ± 7.1%, p < 0.05). We also evaluated the quality of in vitro matured oocytes by in vitro fertilization and single-cell RNA sequencing, and both indicated an improvement in oocyte developmental potential. In conclusion, we successfully obtained the first live dogs using in vitro matured oocytes by adding P4 to optimize the in vitro maturation system of canine oocytes, and established a new and low-cost method to produce dogs via in vitro maturation and in vitro fertilization.

Prevalence and risk analysis of mobile colistin resistance and extended-spectrum ß-lactamase genes carriage in pet dogs and their owners: a population based cross-sectional study.

Mobile colistin resistance gene mcr-1 and extended-spectrum ß-lactamase gene bla CTX-M are highly prevalent in human - and pet-derived bacteria. Isolation of identical strains of mcr-1-positive Escherichia coli (MCRPEC) or bla CTX-M-positive E. coli (CTX-MPEC) from pets and humans highlighted the potential for co-colonization of antibiotic-resistant bacteria which can be a risk for dissemination of resistance genes. In this study, the prevalence of mcr-1 and bla CTX-M carriage from rectal swabs in 299 families (dogs and their owners) were 2.7 and 5.3%, respectively. We identified a significant association of mcr-1 carriage between dogs and their owners. Whilst antibiotic use in the previous three months was associated with bla CTX-M carriage in dogs. Only one instance of dog and owner carrying identical CTX-MPEC was observed. Although the prevalence of identical strains in one family is rare, the huge number of dog ownership worldwide suggest that this threat should not be underestimated.

Sodium houttuyfonate inhibits inflammation by blocking the MAPKs/NF-κB signaling pathways in bovine endometrial epithelial cells.

Sodium houttuyfonate (SH) has traditionally been used for the therapy of inflammatory diseases. In this research, we tried to assess the anti-inflammatory effects of SH on LPS-induced bovine endometrial epithelial cell (bEEC) inflammation. SH cell toxicity was measured using the MTT and LDH assays, and inflammatory cytokine expression was assessed by ELISA, qRT-PCR and Western blotting. We demonstrated that SH was not cytotoxic to bEECs, and that it significantly decreased the LPS-induced mRNA and protein expression of tumor necrosis factor (TNF) α, interleukin (IL)-1ß, IL-6 and IL-8. Furthermore, in LPS-induced bEECs, SH inhibited IκBα degradation and NF-κB p65 phosphorylation, and suppressed the phosphorylation of the mitogen-activated protein kinases (MAPKs), p38, c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK). In conclusion, we found that SH could effectively block the NF-κB-mediated signaling pathway and reduce the inflammatory process, thereby exerting a protective effect on bEECs.

C-Type natriuretic peptide maintains domestic cat oocytes in meiotic arrest.

Recent studies have shown that C-type natriuretic peptide (CNP; encoded by the natriuretic peptide C (NPPC) gene) plays an essential role in maintaining meiotic arrest of mouse and porcine oocytes. However, whether CNP inhibits feline meiotic resumption is not known. In the present study we used a domestic cat model to explore the role played by CNP in feline oocyte meiotic resumption. We determined mRNA expression of genes encoding CNP and its cognate receptor natriuretic peptide receptor 2 (NPR2) in antral follicles. NPPC mRNA was primarily expressed in mural granulosa cells, whereas NPR2 mRNA was predominantly expressed in cumulus cells. Following in vitro culture for 24h, 100nM CNP increased cGMP levels, and maintained meiotic arrest of oocytes associated with cumulus cells. When the duration of in vitro culture increased from 24h to 36h, the ability of CNP to maintain meiotic arrest decreased, and this was accompanied by a decrease in the steady state levels of NPR2 mRNA in cumulus cells. In addition, CNP decreased the rate of degeneration of oocytes. These results indicate that CNP is required to maintain meiotic arrest and prevent degeneration in domestic cat oocytes.

Involvement of oxidative stress and mitogen-activated protein kinase signaling pathways in heat stress-induced injury in the rat small intestine.

Extreme heat stress-induced gastrointestinal injury and dysfunction may occur during summer. We investigated possible mechanisms of heat stress-induced damage in the small intestine using male Sprague-Dawley rats subjected to 2 h of heat stress (40 °C, 60% relative humidity) daily for 10 consecutive days. Rats were killed at specific times immediately following heat treatment to determine: morphological changes by optical and electron microscopy; intestinal permeability using fluorescein isothiocyanate-dextran; production of reactive oxygen species (ROS), malondialdehyde (MDA), and activities of superoxide-dismutase and glutathione-peroxidase by specific assays; phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) by immunocytochemistry and western-blot analysis. The rat intestinal epithelial cell line (IEC-6) and specific MAPK inhibitors were used for in vitro investigation of effects of activation of MAPKs by heat stress. Heat stress caused marked morphological damage to the small intestine and significantly increased intestinal permeability. Heat stress increased ROS and MDA production, and significantly reduced anti-oxidase activity. MAPK activity in small intestine was increased by heat stress. In vitro, heat stress caused damage and apoptosis in IEC-6 cells; inhibition of ERK1/2 activation (by U0126) exacerbated these effects, which were attenuated by inhibition of JNK (by SP600125) and p38 (by SB203580) activation. Hence, heat stress caused severe small intestine injury, increased oxidative stress, and activated MAPK signaling pathways. The in vitro studies indicated that ERK1/2 activation is anti-apoptotic, and JNK and p38 activation are pro-apoptotic in heat stressed intestinal epithelial cells.

Reduction of intestinal mucosal immune function in heat-stressed rats and bacterial translocation.

PURPOSE: The aim of this study was to further understand the effects and mechanism of heat stress on the intestinal mucosal immune system of the rat, including changes in the intestinal mucosal barrier and immune function and their effects on bacterial translocation. MATERIALS AND METHODS: Sprague Dawley (SD) rats were randomly divided into control and heat-stress groups. Both groups were housed in a 25°C environment of 60% relative humidity. The heat-stress group was subjected to 40°C for 2 h daily over 3 days. RESULTS: Compared with the control group villi length in the small intestines of the heat-stress group was shortened. Jejunal mucosa were seriously damaged and the number of goblet cells in the epithelia of the duodenum and jejunum was significantly reduced. Electron microscopy revealed intestinal mucosal disorder, a large number of exudates of inflammatory fibrous material, fuzzy tight junction structure between epithelial cells, and cell gap increases in the heat-stress group. Transcription of IFN-γ, IL-2, IL-4, and IL-10, was significantly reduced, as was that of the intestinal mucosal immune-related proteins TLR2, TLR4, and IgA. The number of CD3(+) T cells and CD3(+)CD4(+)CD8(-) T cells in the mesenteric lymph nodes (MLNs) was significantly lower, while the number of CD3(+)CD4(-)CD8(+) T cells was significantly increased. The bacteria isolated from the MLNs were Escherichia coli. CONCLUSIONS: Heat stress damages rat intestinal mechanical and mucosal immune barriers, and reduces immune function of the intestinal mucosa and mesenteric lymphoid tissues, leading to bacterial translocation.

Frequencies of blood types A, B, and AB in non-pedigree domestic cats in Beijing.

BACKGROUND: Frequencies of blood types A, B, and AB in domestic cats vary geographically and among breeds and have not been reported in China. OBJECTIVE: The purpose of this study was to survey the frequency of blood types in domestic cats in the Beijing area. METHODS: A total of 262 cats from the city of Beijing were blood-typed using a standard tube agglutination assay. All cats were nonpedigree domestic shorthaired and longhaired cats; purebred cats were excluded. Serum obtained from type-B cats and a lectin (Triticum vulgaris) solution served as anti-A and anti-B reagents, respectively. The presence of alloantibodies was also determined in some cats. RESULTS: The frequency of blood types was 88.2% type A, 11.4% type B, and 0.4% type AB. The tube assay resulted in 3+ to 4+ agglutination reactions with either the anti-A or anti-B reagents. The 1 type AB sample showed 3+ agglutination with both anti-A and anti-B reagents; the plasma of that sample did not react with either type-A or type-B RBCs. Tested type-B cats had strong anti-A antibodies. CONCLUSIONS: The frequency of blood type B in the Beijing area was relatively high and similar to that reported for other Asian countries and Australia. Blood-typing is recommended to match donors and recipients before transfusion therapy and planned matings to avoid hemolytic transfusion and neonatal isoerythrolysis reactions, respectively, due to blood-type incompatibility.

Enhancement of Astragalus polysaccharide on the immune responses in pigs inoculated with foot-and-mouth disease virus vaccine.

The effects of Astragalus polysaccharides (APS) on the immune response in pigs immunized with foot-and-mouth disease virus (FMDV) vaccine were investigated. Fifteen pigs were randomly divided into five groups. Four groups were vaccinated with a FMDV inactivated vaccine. Pigs in three experimental groups were administered varying doses of APS (APS1, 5mg/kg; APS2, 10mg/kg; APS3, 20mg/kg). The influence of APS on the number of CD3(+)CD4(-)CD8(+) cytotoxic T cells, CD3(+)CD4(+)CD8(+) T helper memory cells, and CD3(-)CD4(-)CD8(+) natural killer cells among peripheral blood lymphocytes (PBL) in the three APS groups were significant compared to the vaccine group. In vitro stimulation of PBL by Con A and LPS in APS groups induced a stronger proliferative response at 2 and 6 weeks post-inoculation (PI). APS markedly increased the titer of FMDV-specific antibody in a dose-dependent manner, and up-regulated mRNA expression of IFN-γ and IL-6. APS could potentially be used as an immunomodulator for a FMDV vaccine and provide better protection against FMDV.