Protective Effects of Fucoxanthin on Hydrogen Peroxide-Induced Calcification of Heart Valve Interstitial Cells

Cardiovascular diseases such as atherosclerosis and aortic valve sclerosis involve inflammatory reactions triggered by various stimuli, causing increased oxidative stress. This increased oxidative stress causes damage to the heart cells, with subsequent cell apoptosis or calcification. Currently, heart valve damage or heart valve diseases are treated by drugs or surgery. Natural antioxidant products are being investigated in related research, such as fucoxanthin (Fx), which is a marine carotenoid extracted from seaweed, with strong antioxidant, anti-inflammatory, and anti-tumor properties. This study aimed to explore the protective effect of Fx on heart valves under high oxidative stress, as well as the underlying mechanism of action. Rat heart valve interstitial cells under H₂O₂-induced oxidative stress were treated with Fx. Fx improved cell survival and reduced oxidative stress-induced DNA damage, which was assessed by cell viability analysis and staining with propidium iodide. Alizarin Red-S analysis indicated that Fx has a protective effect against calcification. Furthermore, Western blotting revealed that Fx abrogates oxidative stress-induced apoptosis via reducing the expression of apoptosis-related proteins as well as modulate Akt/ERK-related protein expression. Notably, in vivo experiments using 26 dogs treated with 60 mg/kg of Fx in combination with medical treatment for 0.5 to 2 years showed significant recovery in their echocardiographic parameters. Collectively, these in vitro and in vivo results highlight the potential of Fx to protect heart valve cells from high oxidative stress-induced damage.     

Antibiotic susceptibility and prevalence of erythromycin ribosomal methylase gene, erm(B) in Streptococcus spp

The aim of this study was to investigate drug resistance and the genetic relatedness of erythromycin-resistant Streptococcus spp. from different animals and humans in Taiwan. Cumulatively, 248 isolates were collected from 15 animal species and human patients and the susceptibilities of the isolates to six antimicrobial agents including azithromycin (AZI), clarithromycin (CLAR), erythromycin (ERY), spiramycin (SPIR), amoxicillin (AMO), and enrofloxacin (ENRO) were determined by the agar dilution method. The results indicated that resistance among the 248 strains was highest for SPIR, followed by ENRO, CLAR, ERY, AZI, and AMO. The most common resistotypes of the isolates from mammals and aquatic animals were AZI-CLAR-ERY-SPIR (27.5%) and SPIR (55.1%), respectively. The presence of ERY-resistant genes was confirmed by PCR. The erm gene was amplified from 28 isolates (20.6%) by PCR for further investigation. The predominant erm gene in the ERY-resistant isolates was the erm(B) gene. The phylogenetic analysis of the erm(B) gene results indicated that there was a close genetic relationship among all the strains but the genotypic clusters did not show clear segregation of the isolates according to the source or region.     

Farm management factors associated with bulk tank total bacterial count in Irish dairy herds during 2006/07

Research has shown that total bacterial count (TBC), which is the bacterial growth per ml of milk over a fixed period of time, can be decreased by good hygiene and farm management practices. The objective of the current study was to quantify the associations between herd management factors and bulk tank TBC in Irish spring calving, grass-based dairy herds. The relationship between bulk tank TBC and farm management and infrastructure was examined using data from 400 randomly selected Irish dairy farms where the basal diet was grazed grass. Herd management factors associated with bulk tank TBC were identified using linear models with herd annual total bacterial score (i.e., arithmetic mean of the natural logarithm of bulk tank TBC) included as the dependent variable. All herd management factors were individually analysed in a separate regression model, that included an adjustment for geographical location of the farm. A multiple stepwise regression model was subsequently developed. Median bulk tank TBC for the sample herds was 18,483 cells/ml ranging from 10,441 to 130,458 cells/ml. Results from the multivariate analysis indicated that the following management practices were associated with low TBC; use of heated water in the milking parlour; participation in a milk recording scheme; and tail clipping of cows at a frequency greater than once per year. Increased level of hygiene of the parlour and cubicles were also associated with lower TBC. Herd management factors associated with bulk tank TBC in Irish grazing herds were generally in agreement with most previous studies from confinement systems of milk production.     

Molecular characterization of plasmids with antimicrobial resistant genes in avian isolates of Pasteurella multocida

The complete nucleotide sequences of two plasmids from avian isolates of Pasteurella multocida that caused outbreaks of fowl cholera in Taiwan were determined. The entire sequences of the two plasmids, designated as pJR1 and pJR2, were 6792 bp and 5252 bp. Sequence analysis showed that the plasmid pJR1 contained six major genes: the first gene (sulII) encoded a type II sulfonamide resistant dihydropteroate synthase, the second gene (tetG) encoded a tetracycline resistance protein, the third gene (catB2) encoded a chloramphenicol acetyltransferase, the fourth gene (rep) encoded a replication protein, and the fifth and sixth genes (mbeCy and deltambeAy) encoded proteins involved in the mobilization of plasmid. The plasmid pJR2 contained five major genes: the first gene (deltaintI1) encoded a truncated form of a type I integrase, the second gene (aadA1) encoded an aminoglycoside adenylyltransferase that confers resistance to streptomycin and spectinomycin, the third gene (blaP1) encoded a beta-lactamase that confers resistance to ampicillin and carbenicillin, and the fourth and fifth genes might encode proteins involved in the plasmid replication or segregation. Sequence comparisons showed that the antibiotic resistance genes found in pJR1 and pJR2 exhibited a high degree of sequence homology to the corresponding genes found in a great variety of gram-negative bacteria, including Escherichia coli, Salmonella enterica Typhimurium DT104, Psedomonas spp., P. multocida, Mannheimia spp., and Actinobacills pleuropneumoniae, which suggests that these resistance genes were disseminated in these bacteria. Although sulII and tetG genes were found previously in P. multocida or Mannheimia spp., this is the first report on the presence of catB2, aadA1, and blaP1 genes in bacteria of the family Pasturellaceae. Moreover, the aadA1 and blaP1 genes found in pJR2 were organized into an integron structure, which is a site-specific recombination system capable of capturing and mobilizing antibiotic resistance genes. This is also the first report on the presence of an integron in bacteria of the family Pasteurellaceae. The presence of a P. multocida integron might facilitate the spreading of antibiotic resistance genes between P. multocida and other gram-negative bacteria.     

Expression of infectious laryngotracheitis virus glycoproteins in Escherichia coli and their application in enzyme-linked immunosorbent assay

Three glycoproteins of infectious laryngotracheitis virus (ILTV), gC, gE, and gp60, were expressed in Escherichia coli as fusion proteins with a 6-histidine tag at their amino termini. The proteins expressed, designated as r-gC, r-gp60, and r-gE, all retain their antigenicity, as revealed by Western blot with chicken antiserum against ILTV. However, only r-gp60 and r-gE, but not r-gC, were found to be soluble. The soluble r-gp60 and r-gE were purified by a nickel column and then used as the enzyme-linked immunosorbent assay (ELISA) antigen for detecting ILTV-specific antibodies. The diagnostic potential of r-gE and r-gp60 ELISA was assessed with the use of sera prepared from vaccinated or unvaccinated chickens of either specific-pathogen-free (SPF) or field origins. The result shows that r-gp60 and r-gE ELISA could discriminate vaccinated SPF chickens from unvaccinated ones 2 wk postvaccination. Moreover, r-gp60 and r-gE ELISA could also discriminate vaccinated field flocks from unvaccinated ones. This result indicates that r-gp60 and r-gE might serve as an alternative ELISA antigen for detecting ILTV-specific antibodies. Moreover, r-gp60 or r-gE ELISA might play an important role in the eradication of infectious laryngotracheitis (ILT) in the future when the gp60- or gE-deleted marker vaccine of ILT is available.     

Application of response surface methodology to the study of methyl glucoside polyester synthesis parameters in a solvent-free system

Response surface methodology (RSM) and 3-level-3-factor fractional factorial design were used to evaluate the effects of synthesis parameters, including reaction time (4 to 8 h), temperature (110 to 130 degrees C), and substrate molar ratio of fatty acid methyl esters (FAME) from soybean oil to methyl glucoside (4:1 to 6:1) on the percent molar conversion to methyl glucoside polyester (MGPE), utilizing 15 g of methyl glucoside as the reactant in a solvent-free system. All synthesis variables (reaction time, temperature, and substrate molar ratio) exhibited significant effects on percent molar conversion to MPGE in the experimental range. Optimization of the synthesis reaction was suggested by ridge max analysis to compute the estimated ridge of optimum response for increasing radii from the center of the original design. Based on the ridge max analysis, optimum conditions were: reaction time 6.3 h, synthesis temperature 123.8 degrees C, and substrate molar ratio 5.9:1. The predicted molar conversion was 55.68% (i.e., 15 g methyl glucoside yielded 56.5 g MGPE) at the optimum point.