Rumen fermentation and microbial diversity of sheep fed a high-concentrate diet supplemented with hydroethanolic extract of walnut green husks

Wei Huan,Liu Jiancheng,Liu Mengjian,Zhang Huiling,Chen Yong 아세아·태평양축산학회 2024 Animal Bioscience Vol.37 No.4

Objective: This study aimed to assess the impact of a hydroethanolic extract of walnut green husks (WGH) on rumen fermentation and the diversity of bacteria, methanogenic archaea, and fungi in sheep fed a high-concentrate diet. Methods: Five healthy small-tailed Han ewes with permanent rumen fistula were selected and housed in individual pens. This study adopted a self-controlled and crossover design with a control period and an experimental period. During the control period, the animals were fed a basal diet (with a ratio of concentrate to roughage of 65:35), while during the treatment period, the animals were fed the basal diet supplemented with 0.5% hydroethanolic extract of WGH. Fermentation parameters, digestive enzyme activities, and microbial diversity in rumen fluid were analyzed. Results: Supplementation of hydroethanolic extract of WGH had no significant effect on feed intake, concentrations of total volatile fatty acids, isovalerate, ammonia nitrogen, and microbial protein (p>0.05). However, the ruminal pH, concentrations of acetate, butyrate and isobutyrate, the ratio of acetate to propionate, protozoa count, and the activities of filter paper cellulase and cellobiase were significantly increased (p<0.05), while concentrations of propionate and valerate were significantly decreased (p<0.05). Moreover, 16S rRNA gene sequencing revealed that the relative abundance of rumen bacteria Christensenellaceae R7 group, Saccharofermentans, and Ruminococcaceae NK4A214 group were significantly increased, while Ruminococcus gauvreauii group, Prevotella 7 were significantly decreased (p<0.05). The relative abundance of the fungus Pseudomonas significantly increased, while Basidiomycota, Fusarium, and Alternaria significantly decreased (p<0.05). However, there was no significant change in the community structure of methanogenic archaea. Conclusion: Supplementation of hydroethanolic extract of WGH to a high-concentrate diet improved the ruminal fermentation, altered the structure of ruminal bacterial and fungal communities, and exhibited beneficial effects in alleviating subacute rumen acidosis of sheep.

Salt Tolerance is Conferred in Arabidopsis by Overexpression of the Vacuolar Na (+)/H (+) Antiporter Gene SsNHX2, an Alternative Splicing Variant of SsNHX1, from Suaeda salsa

Weihuan Li,Quan Zhang,Xiangqiang Kong,Chunxia Wu,Xiuling Ma,Hui Zhang,Yanxiu Zhao 한국식물학회 2009 Journal of Plant Biology Vol.52 No.2

Vacuolar Na+/H+ antiporters catalyze the exchange of Na+ for H+ across vacuolar membranes and compartmentalize Na+ into vacuoles. They play important roles in cellular pH and Na+ homeostasis. The SsNHX1 gene was previously cloned from a typical euhalophyte, Suaeda salsa. Its cloning revealed another N-terminus truncated transcript, SsNHX2. This potentially alternative splicing variant was truncated from the 49 amino acid residues (aa) of the N terminus of SsNHX1. To compare their degree of salt tolerance, we over-expressed SsNHX1 and SsNHX2 in Arabidopsis. Southern and northern blot analyses showed that both genes had been integrated into that genome and had expressed in several lines. Two types of transgenic plants grew more vigorously than the wild type (WT) under salt stress, but no remarkable differences were found between those SsNHX1 and SsNHX2 transformants. Physiological analyses also supported this phenotype. Both fresh and dry weights of the transgenics as well as their accumulations of Na+ and K+ under salinity were much higher than that of WT, but differences were not significant between SsNHX1 and SsNHX2 plants for any of those parameters. These results suggest that SsNHX2 is a functional Na+/H+ antiporter like SsNHX1 and their levels of salt tolerance are similar.

Integrative medicine research for improving female reproductive health during COVID-19

Jue Zhou,Weihuan Hu,Qu Fan 한국한의학연구원 2022 Integrative Medicine Research Vol.11 No.4

Core-Shell Structured Polystyrene Coated Carbonyl Iron Microspheres and their Magnetorheology

Xuemei Quan,Weihuan Chuah,Yongsok Seo,Hyoung Jin Choi IEEE 2014 IEEE transactions on magnetics Vol.50 No.1

<P>Soft magnetic carbonyl iron (CI) microparticle, possessing high magnetic saturation with less magnetic hysteresis, was mostly applied as an active material in magnetorheological (MR) fluids. However, pure CI suspension is known to have poor dispersion stability in the MR fluid system. To overcome this problem, we fabricated polystyrene (PS)-coated CI particles through a simple coating method of dispersion polymerization. Surface morphology of synthesized PS coated CI was observed using scanning electron microscopy. Performance of this MR fluid dispersed in silicone oil, including shear stress and shear viscosity, was measured using a rotational parallel disk rheometer in a steady shear flow and suspension stability was examined by a Turbiscan apparatus. The PS-coated CI suspension was found to improve settling of the CI particles without much deterioration of MR performance.</P>

Catabolite Control Protein A of Streptococcus suis Type 2 Contributes to Sugar Metabolism and Virulence

Yulong Tang,Wei Wu,Xiaoyan Zhang,Zhongyan Lu,Jianshun Chen,Weihuan Fang 한국미생물학회 2012 The journal of microbiology Vol.50 No.6

Catabolite control protein A (CcpA) is the major transcriptional regulator in carbon catabolite repression in several Gram-positive bacteria. We attempted to characterize the role of a CcpA homologue of Streptococcus suis type 2 in sugar metabolism and virulence. Addition of glucose or sucrose to the defined medium significantly reduced the activity of raffinose-inducible α-galactosidase, cellobiose-inducible β-glucosidase, and maltose-inducible α-glucosidase of the wildtype strain by about 9, 4, and 2-3 fold, respectively. Deletion of ccpA substantially derepressed the effects of repressing sugars on α-galactosidase or β-glucosidase activity. The ccpA deletion mutant showed reduced expression of virulence genes sly and eno (P<0.05), decreased adhesion to and invasion into endothelial cells (P<0.05), and attenuated virulence to mice with significant reduction of death rate and bacterial burden in organs, as compared to the wild-type strain. Both the in vitro and in vivo defect phenotypes were reversible by ccpA complementation. Thus, this study shows that CcpA of S. suis type 2 plays an important role in carbon catabolite repression and virulence.

Deciphering the Biodiversity of Listeria monocytogenes Lineage III Strains by Polyphasic Approaches

Hanxin Zhao,Jianshun Chen,Chun Fang,Ye Xia,Changyong Cheng,Lingli Jiang,Weihuan Fang 한국미생물학회 2011 The journal of microbiology Vol.49 No.5

Listeria monocytogenes is a foodborne pathogen of humans and animals. The majority of human listeriosis cases are caused by strains of lineages I and II, while lineage III strains are rare and seldom implicated in human listeriosis. We revealed by 16S rRNA sequencing the special evolutionary status of L. monocytogenes lineage III, which falls between lineages I and II strains of L. monocytogenes and the non-pathogenic species L. innocua and L. marthii in the dendrogram. Thirteen lineage III strains were then characterized by polyphasic approaches. Biochemical reactions demonstrated 8 biotypes, internalin profiling identified 10 internalin types clustered in 4 groups, and multilocus sequence typing differentiated 12 sequence types. These typing schemes show that lineage III strains represent the most diverse population of L. monocytogenes, and comprise at least four subpopulations IIIA-1, IIIA-2, IIIB, and IIIC. The in vitro and in vivo virulence assessments showed that two lineage IIIA-2 strains had reduced pathogenicity, while the other lineage III strains had comparable virulence to lineages I and II. The IIIB strains are phylogenetically distinct from other subpopulations, providing additional evidence that this sublineage represents a novel lineage. The two biochemical reactions L-rhamnose and L-lactate alkalinization, and 10 internalins were identified as potential markers for lineage III subpopulations. This study provides new insights into the biodiversity and population structure of lineage III strains, which are important for understanding the evolution of the L. monocytogenes-L. innocua clade.

Continuous Passaging of a Recombinant C-Strain Virus in PK-15 Cells Selects Culture-Adapted Variants that Showed Enhanced Replication but Failed to Induce Fever in Rabbits

( Chao Tong ),( Ning Chen ),( Xun Liao ),( Xuemei Yuan ),( Mengjiao Sun ),( Xiaoliang Li ),( Weihuan Fang ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.9

Classical swine fever virus (CSFV) is the etiologic agent of classical swine fever, a highly contagious disease that causes significant economic losses to the swine industry. The lapinized C-strain, a widely used vaccine strain against CSFV, has low growth efficiency in cell culture, which limits the productivity in the vaccine industry. In this study, a recombinant virus derived from C-strain was constructed and subjected to continuous passaging in PK-15 cells with the goal of acquiring a high progeny virus yield. A cell-adapted virus variant, RecCpp80, had nearly 1,000-fold higher titer than its parent C-strain but lost the ability to induce fever in rabbits. Sequence analysis of cell-adapted RecC variants indicated that at least six nucleotide changes were fixed in RecCpp80. Further adaption of RecCpp80 variant in swine testicle cells led to a higher virus yield without additional mutations. Introduction of each of these residues into the wild-type RecC backbone showed that one mutation, M979R (T3310G), located in the C-terminal region of E2 might be closely related to the cell-adapted phenotype. Rabbit inoculation revealed that RecCpp80+10 failed to induce fever in rabbits, whereas RecCpp40₊₁₀ caused a fever response similar to the commercial C-strain vaccine. In conclusion, the C-strain can be adapted to cell culture by introducing specific mutations in its E2 protein. The mutations in RecCpp80 that led to the loss of fever response in rabbits require further investigation. Continuous passaging of the C-strain-based recombinant viruses in PK-15 cells could enhance its in vitro adaption. The non-synonymous mutations at 3310 and 3531 might play major roles in the enhanced capacity of general virus reproduction. Such findings may help design a modified C-strain for improved productivity of commercial vaccines at reduced production cost.

A serine/threonine phosphatase 1 of Streptococcus suis type 2 is an important virulence factor

Lihua Fang,Jingjing Zhou,Pengcheng Fan,Yunkai Yang,Hongxia Shen,Weihuan Fang 대한수의학회 2017 Journal of Veterinary Science Vol.18 No.4

Streptococcus suis is regarded as one of the major pathogens of pigs, and Streptococcus suis type 2 (SS2) is considered a zoonotic bacterium based on its ability to cause meningitis and streptococcal toxic shock-like syndrome in humans. Many bacterial species contain genes encoding serine/threonine protein phosphatases (STPs) responsible for dephosphorylation of their substrates in a single reaction step. This study investigated the role of stp1 in the pathogenesis of SS2. An isogenic stp1 mutant (stp1) was constructed from SS2 strain ZJ081101. The stp1 mutant exhibited a significant increase in adhesion to HEp-2 and bEnd.3 cells as well as increased survival in RAW264.7 cells, as compared to the parent strain. Increased survival in macrophage cells might be related to resistance to reactive oxygen species since the stp1 mutant was more resistant than its parent strain to paraquat-induced oxidative stress. However, compared to parent strain virulence, deletion of stp1 significantly attenuated virulence of SS2 in mice, as shown by the nearly double lethal dose 50 value and the lower bacterial load in organs and blood in the murine model. We conclude that Stp1 has an essential role in SS2 virulence.

DnaJ of Streptococcus suis Type 2 Contributes to Cell Adhesion and Thermotolerance

Zhang, Xiaoyan,Jiang, Xiaowu,Yang, Ling,Fang, Lihua,Shen, Hongxia,Lu, Xingmeng,Fang, Weihuan The Korean Society for Microbiology and Biotechnol 2015 Journal of microbiology and biotechnology Vol.25 No.6

To examine if the molecular chaperone DnaK operon proteins of Streptococcus suis type 2 (SS2) are involved in adhesion to host cells, the abundance values of these proteins from the surface of two SS2 strains of different adhesion capability were compared. Their roles in growth and adhesion to human laryngeal epithelial cell line HEp-2 cells were investigated on SS2 strain HA9801 and its mutants with DnaK operon genes partially knocked-out (PKO mutant) under heat stress. The major difference was that DnaJ was more abundant in strain HA9801 than in strain JX0811. Pretreatment of the bacteria with hyperimmune sera to DnaJ, but not with those to other proteins, could significantly reduce SS2 adhesion to HEp-2 cells. PKO of dnaJ g ene resulted in decreased SS2 growth at 37℃ and 42℃, and reduced its adhesion to HEp-2 cells. The wild-type strain stressed at 42℃ had increased expression of DnaJ on its surface and elevated adhesion to HEp-2 cells, which was also inhibitable by DnaJ specific antiserum. These results indicate that the DnaJ of S. suis type 2 is important not only for thermotolerance but also for adhesion to host cells. Because DnaJ expression is increased upon temperature upshift with increased exposure on the bacterial surface, the febrile conditions of the cases with systemic infections might help facilitate bacterial adhesion to host cells. DnaJ could be one of the potential candidates as a subunit vaccine because of its good immunogenicity.