Molecular characterisation and antimicrobial resistance of Streptococcus agalactiae isolates from dairy farms in China.

Introduction: Streptococcus agalactiae (S. agalactiae) is a pathogen causing bovine mastitis that results in considerable economic losses in the livestock sector. To understand the distribution and drug resistance characteristics of S. agalactiae from dairy cow mastitis cases in China, multilocus sequence typing (MLST) was carried out and the serotypes and drug resistance characteristics of the bacteria in the region were analysed. Material and Methods: A total of 21 strains of bovine S. agalactiae were characterised based on MLST, molecular serotyping, antimicrobial susceptibility testing, and the presence of drug resistance genes. Results: The serotypes were mainly Ia and II, accounting for 47.6% and 42.9% of all serotypes, respectively. Five sequence types (STs) were identified through MLST. The ST103 and ST1878 strains were predominant, with rates of 52.4% and 28.6%, respectively. The latter is a novel, previously uncharacterised sequence type. More than 90% of S. agalactiae strains were susceptible to penicillin, oxacillin, cephalothin, ceftiofur, gentamicin, florfenicol and sulfamethoxazole. The bacteria showed high resistance to tetracycline (85.7%), clindamycin (52.1%) and erythromycin (47.6%). Resistant genes were detected by PCR, the result of which showed that 47.6%, 33.3% and 38.1% of isolates carried the tet(M), tet(O) and erm(B) genes, respectively. Conclusion: The results of this study indicate that S. agalactiae show a high level of antimicrobial resistance. It is necessary to monitor the pathogens of mastitis to prevent the transmission of these bacteria.

Partial Replacement of Oat Hay with Whole-Plant Hydroponic Barley Seedlings Modulates Ruminal Microbiota and Affects Growth Performance of Holstein Heifers.

The dairy industry is facing challenges in balancing forage supply and crop production. Therefore, forage supply based on a farm land-saving approach should be developed to overcome the human−livestock competition on farmland. The objective of this study was to learn the potential impact of partially replacing oat hay with whole-plant hydroponic barley seedlings (HBS) produced via a land-saving hydroponic method on growth performance, digestibility, and rumen microbiota in Holstein dairy heifers. In total, 39 Holstein heifers were randomly divided into 13 blocks based on age and body weight for an 8-week experimental period. The heifers within each block were randomly allocated to one of three diets group: (1) 0% HBS and 16% oat hay (CON); (2) 4% HBS and 12% oat hay (25% HBS); and (3) 8% HBS and 8% oat hay (50% HBS). Compared to CON, feed intake, growth performance, and body N retention were similar to those in cows fed 25% HBS but lower in 50% HBS-fed animals (p < 0.05). Reduced digestibility (crude protein (CP) and organic matter (OM)) was observed in 50% HBS animals (p < 0.05). Compared to the control, the levels of Lachnospiraceae_XPB1014_group, Bacillus, and Colidextribacter were higher, but the levels of Sphaerochaeta and Ruminiclostridium were lower in 50% HBS animals (p < 0.05). Additionally, the digestibility of CP (p < 0.01, r = −0.61) and ether extract (EE) (p < 0.01, r = −0.58) was negatively correlated with Lachnospiraceae_XPB1014_group. The digestibility of OM (p = 0.01, r = −0.55), neutral detergent fiber (NDF) (p = 0.01, r = −0.56), acid detergent fiber (ADF) (p = 0.02, r = −0.52), and CP (p < 0.01, r = −0.61) was negatively correlated with Bacillus. The digestibility of NDF (p = 0.02, r = −0.52) and ADF (p = 0.03, r = −0.50) was negatively correlated with Colidextribacter. The digestibility of OM (p = 0.03, r = 0.50), NDF (p = 0.03, r = 0.50), and ADF (p = 0.03, r = 0.49) was positively correlated with Ruminiclostridium. The digestibility of OM (p = 0.04, r = 0.47), CP (p < 0.01, r = 0.58), and EE (p = 0.03, r = 0.49) was positively correlated with unclassified_f_Rikenellaceae. The digestibility of CP was positively correlated with Sphaerochaeta (p = 0.02, r = 0.53). In conclusion, the current study suggests that HBS could replace oat hay in a ratio-dependent manner. The reduced growth performance could be caused by lower feed intake and digestibility, which may be attributed to the alteration in the rumen's microbial population. Further exploration of the inhibiting factors of HBS would broaden the application of hydroponic feed in the future.

Integrated meta-omics reveals new ruminal microbial features associated with feed efficiency in dairy cattle.

BACKGROUND: As the global population continues to grow, competition for resources between humans and livestock has been intensifying. Increasing milk protein production and improving feed efficiency are becoming increasingly important to meet the demand for high-quality dairy protein. In a previous study, we found that milk protein yield in dairy cows was associated with the rumen microbiome. The objective of this study was to elucidate the potential microbial features that underpins feed efficiency in dairy cows using metagenomics, metatranscriptomics, and metabolomics. RESULTS: Comparison of metagenomic and metatranscriptomic data revealed that the latter was a better approach to uncover the associations between rumen microbial functions and host performance. Co-occurrence network analysis of the rumen microbiome revealed differential microbial interaction patterns between the animals with different feed efficiency, with high-efficiency animals having more and stronger associations than low-efficiency animals. In the rumen of high-efficiency animals, Selenomonas and members of the Succinivibrionaceae family positively interacted with each other, functioning as keystone members due to their essential ecological functions and active carbohydrate metabolic functions. At the metabolic level, analysis using random forest machine learning suggested that six ruminal metabolites (all derived from carbohydrates) could be used as metabolic markers that can potentially differentiate efficient and inefficient microbiomes, with an accuracy of prediction of 95.06%. CONCLUSIONS: The results of the current study provided new insights into the new ruminal microbial features associated with feed efficiency in dairy cows, which may improve the ability to select animals for better performance in the dairy industry. The fundamental knowledge will also inform future interventions to improve feed efficiency in dairy cows. Video Abstract.

Gastrodin promotes hippocampal neurogenesis via PDE9-cGMP-PKG pathway in mice following cerebral ischemia.

Gastrodin, which is extracted from the Chinese herbal medicine Gastrodia elata Blume, can ameliorate neurogenesis after cerebral ischemia. However, it's possible underlying mechanisms remain still elusive. PDE9-cGMP-PKG signaling pathway is involved in the proliferation of neural stem cells (NSCs) after cerebral ischemia. In this study, we investigated whether the beneficial effect of gastrodin on hippocampal neurogenesis after cerebral ischemia is correlated with the PDE9-cGMP-PKG signaling pathway. Bilateral common carotid artery occlusion (BCCAO) in mice and oxygen-glucose deprivation/reoxygenation (OGD/R) in primary cultured hippocampal NSCs were used to mimic brain ischemic injury. The Morris water maze (MWM) test was executed to detect spatial learning and memory. Proliferation, differentiation, and mature neurons were examined using immunofluorescence. The survival and proliferation of NSCs were assessed by CCK-8 assay and BrdU immunofluorescence staining, respectively. ELISA and western blot were used to detect the level of the PDE9-cGMP-PKG signaling pathway. In BCCAO mice, administering gastrodin (50 and 100 mg/kg) for 14 d restored cognitive behaviors; meanwhile, neurogenesis in hippocampus was stimulated, and PDE9 was inhibited and cGMP-PKG was activated by gastrodin. Consistent with the results, administering gastrodin (from 0.01-1 µmol/L) for 48 h dose-dependently ameliorated the cell viability and promoted greatly the proliferation in primary hippocampal NSCs exposed to OGD/R. Gastrodin further decreased PDE9 activity and up-regulated cGMP-PKG level. KT5823, a PKG inhibitor, markedly abrogated the protective effects of gastrodin on OGD/R-injured NSCs, accompanied by the down-regulation of PKG protein expression, but had no effects on PDE9 activity and cGMP level. Gastrodin could accelerate hippocampal neurogenesis after cerebral ischemia, which is mediated, at least partly, by PDE9-cGMP-PKG signaling pathway.

Activation of ephrinb1/EPHB2/MAP-2/NMDAR Mediates Hippocampal Neurogenesis Promoted by Transcranial Direct Current Stimulation in Cerebral-Ischemic Mice.

tDCS, a new, safe, non-invasive physical therapy method, is often used in motor dysfunction rehabilitation. However, the effects and underlying mechanisms of tDCS on hippocampal neurogenesis after cerebral ischemia (CI) are still unclear. This study aimed to investigate the promotive effect and mechanism of repetitive anodal-tDCS on hippocampal neurogenesis after CI in mice. The CI model in mice was established using bilateral common carotid artery occlusion (BCCAO). The pathological changes in the hippocampal CA1 region and cognitive function were assessed by hematoxylin and eosin staining and Morris water maze test, respectively. Hippocampal neurogenesis was observed by immunofluorescence staining. The levels of expression of ephrinb1, EPHB2, MAP-2, and NMDAR in the hippocampi were analyzed by qRT-PCR and Western blotting. Compared with the sham mice, the model mice showed significant neuronal damage in the hippocampal CA1 region (P < 0.01), cognitive dysfunction (P < 0.01), and endogenous hippocampal neurogenesis (P < 0.01). These results suggested that the CI model was successfully established, and that CI could promote endogenous hippocampal neurogenesis, but this hippocampal neurogenesis was unable to recover cognitive dysfunction. Compared with the model mice, the tDCS mice had ameliorated pathological damage in the CA1 region (P < 0.01), improved cognitive function (P < 0.01), increased hippocampal neurogenesis (P < 0.01), and increased mRNA and protein expression of ephrinb1, EPHB2, MAP-2, and NMDAR (P < 0.05). Repetitive anodal-tDCS can promote hippocampal neurogenesis and improve cognitive function in CI mice. The effect may be related to the activation of the ephrinb1/EPHB2/MAP-2/NMDAR signaling pathway.

Curcumin promotes neurogenesis of hippocampal dentate gyrus via Wnt/ß-catenin signal pathway following cerebral ischemia in mice.

OBJECTIVES: To investigate whether curcumin promotes hippocampal neurogenesis in the cerebral ischemia (CI) mice via Wnt/ß-catenin signaling pathway. METHODS: Male C57BL/6 mice were randomly divided into groups: sham operation group (Sham), cerebral ischemic group (CI), curcumin treatment group (50, 100 mg/kg/d, i.p.) and curcumin (100 mg/kg/d) + DKK1 (a blocker of Wnt receptor, 200 ng/d, icv) group. CI was induced by bilateral common carotid arteries occlusion (BCCAO) for 20 min. The Morris water maze test was conducted to detect spatial learning and memory. Immunofluorescence staining was used to examine the proliferation and differentiation of immature neurons in the hippocampal dentate gyrus. The proteins involved in neurogenesis and Wnt signaling pathway were examined using Western blot assay. RESULTS: Curcumin significantly alleviated cognitive deficits induced by CI. Curcumin dose-dependently increased the proliferation of neural stem cells and promoted the differentiation and maturation of newly generated neural cells into neurons. Curcumin also increased the expression of proteins involved in neurogenesis (including Ngn2, Pax6 and NeuroD 1) and the Wnt/ß-catenin signaling pathway. Moreover, the forenamed effects of curcumin were abolished by pretreatment with DKK1, a blocker of Wnt receptor. CONCLUSION: Curcumin promotes hippocampal neurogenesis by activating Wnt/ß-catenin signaling pathway to ameliorate cognitive deficits after acute CI.

[Gastrodin improves hippocampal neurogenesis by NO-cGMP-PKG signaling pathway in cerebral ischemic mice].

This paper was aimed to investigate the effect of gastrodin( GAS) on hippocampal neurogenesis after cerebral was chemic and to explore its mechanism of action related to NO. The cerebral ischemia model of C57 BL/6 mice was established by bilateral common carotid artery occlusion. The pathological changes in hippocampal CA1 region and the cognitive function of mice were assessed by HE staining and Morris water maze test,respectively. The count of Brd U/Neu N positive cells in dentate gyrus was detected by immunofluorescence assay. The NOS activity and the NO content were determined by colorimetric and nitrate reduction methods,respectively.The level of c GMP was measured by ELISA kit,and the PKG protein expression was tested by Western blot. On postoperative day 8,the hippocampal CA1 pyramidal neurons of mice showed irregular structure,with obvious nuclear pyknosis,loose cell arrangement and obvious decrease in the number of neurons. On postoperative day 29,the spatial learning ability and memory were decreased. These results indicated cerebral ischemia in mice. Meanwhile,the Brd U/Neu N positive cells were increased significantly in ischemic mice,indicating that neurogenesis occurred in hippocampus after cerebral ischemia. Treatment with different doses of gastrodin( 50 and 100 mg·kg-1) significantly ameliorated the pathological damages in the CA1 region,improved the ability of learning and memory,and promoted hippocampal neurogenesis. At the same time,both the NOS activity and the NO concentration were decreased in model group,but the c GMP level was increased,and the PKG protein expression was up-regulated. Gastrodin administration activated the NOS activity,promoted NO production,further increased c GMP level and up-regulated PKG protein expression. These results suggested that gastrodin can promote hippocampal neurogenesis after cerebral ischemia and improve cognitive function in mice,which may be related to the activation of NO-cGMP-PKG signaling pathway.

Hypoxia attenuates Hsp90 inhibitor 17-DMAG-induced cyclin B1 accumulation in hepatocellular carcinoma cells.

Hypoxia stress plays a pivotal role in tumor formation, proliferation, and invasion. Conventional chemotherapy is less effective in the hypoxia microenvironment of solid tumor. Heat shock protein 90 (Hsp90) is an important molecular chaperone in cancer cells and has been a pharmaceutical target for decades. However, Hsp90 inhibitors demonstrate limited effect on solid tumor and the mechanism underlying is not clear. To determine whether hypoxia impairs the therapeutic effect of Hsp90 N-terminal inhibitor, 17-demethoxygeldanamycin hydrochloride (17-DMAG), in live cancer cells, we measured cell proliferation and cell cycle distribution. Cell proliferation assay indicates that hypoxia obviously promotes the proliferation of HepG2 and Huh7 cells after 24, 48, and 72 h and impairs 17-DMAG-induced G2/M arrest in liver cancer cells. As a client protein of Hsp90, cyclin B1 is critical for the transition from G2 to M phase and is related to the prognosis of the patients. We further checked the cyclin B1 messenger RNA (mRNA) level, protein level, ubiquitination of cyclin B1, nuclear translocation, and degradation of cyclin B1 affected by hypoxia after 17-DMAG treatment. The results demonstrate that hypoxia decreases the transcription of cyclin B1 and accelerates the ubiquitination, nuclear translocation, and degradation of cyclin B1. Taken together, our results suggest that hypoxia attenuates cyclin B1 accumulation induced by 17-DMAG and, hence, alleviates 17-DMAG-induced G2/M arrest.

Expression of Hsp90α and cyclin B1 were related to prognosis of esophageal squamous cell carcinoma and keratin pearl formation.

Hsp90α (heat shock protein 90α), one of the important molecular chaperones in cancer cell signal transduction, has been a new candidate target for cancer therapy. Cyclin B1, the client protein of Hsp90α, plays a key role as a mitotic cyclin in the G2-M phase transition during the cell cycle progression. However, the relationship between the level of HSP90α and cyclin B1, the location of Hsp90α and cyclin B1 in prognosis of esophageal squamous cell carcinoma (ESCC) has not been examined. Here, we demonstrate that the diagnostic significance of Hsp90α and cyclin B1 by immunohistochemistry and the association of Hsp90α and cyclin B1 expression in ESCC. In the specimens from 105 ESCC patients (81 stained with Hsp90α antibody by Immunohistochemistry, 65 with cyclin B1 antibody, and among them, 41 paired specimens were stained with Hsp90α and cyclin B1 respectively, and then checked for the correlation of the level and location of Hsp90α and cylcin B1. The positivity rate of Hsp90α and cyclin B1 expression were 96.3% (78 of 81) and 84.6% (55 of 65) respectively. Both of them, the expression levels are associated with the clinical pathological stage (Hsp90α, p=0.027; cyclin B1, p=0.007). No association was found between Hsp90α or cyclin B1 and gender, age, tumor location. As to TMN stage, there is no association with the level of Hsp90α, However, cyclin B1 expression is significantly related to tumor status (p=0.002). Interestingly, Hsp90α expression was negatively correlated to cyclin B1 expression (Gamma=-0.692, p=0.007) in the keratin pearls though there is a positive correlation in the other areas of tumor (Gamma=0.503, p=0.015), which suggest Hsp90α might play diverse roles in the cyclin B1 expression and cyclin B1 related cell cycle regulation in the different area of tumor. These findings demonstrated that the expression of Hsp90α, cyclin B1 protein is associated with tumor malignancy and prognosis for patients with human esophageal squamous cell carcinoma, and Hsp90α might be involved in cyclin B1 expression regulation and cell cycle regulation in keratin peal formation of ESCC.