Solubility of amaranth seed proteins in sodium sulphate and sodium chloride: the main factor in quantitative extraction for analysis

Nitrogen was extracted more efficiently from amaranth seed with 0.04 M Na₂SO₄ (5% w/v) than with either 0.09 M or 0.17 M NaCl (5% or 10% w/v), despite both solutions having the same ionic strength (μ= 1). Solubility of saline soluble proteins (albumin ± globulin) was very poor in either water or 1M NaCl, but increased in 0.4M NaCl at alkaline pH between 7 and 10. Globulins were very soluble in 0.4M NaCl at a pH 9. Albumin was the main storage protein. Saline soluble proteins formed very weak gels.     

Modulation of the antioxidant/pro-oxidant balance,cytotoxicity and antiviral actions of grape seed extracts

Grape seed extracts (GSEs) were investigated in yeast cells harbouring defects in their antioxidant system (regarding the cellular growth and growth recovery from H₂O₂ insult). GSEs antioxidant activity was detected in wild-type and mutant strains Δcta1, Δgsh1 and Δoye2glr1, while pro-oxidant activity in Δsod1 cells was seen. Assessment of proliferation of prostate cancer PC3 and HBV-replicating HepG2 2.2.15 cells treated with GSEs has shown higher cytotoxicity of red grape seed extract (RW) than white grape seed extract (WW) subjective to dose and period of administration. No antiviral effect was detected by measuring the secreted virion particles in HepG2 2.2.15 cells treated with GSEs. The GSEs play a dual antioxidant/pro-oxidant role in vivo according with the cellular antioxidant system deficiencies and exhibit cytotoxic properties in PC3 and HepG2 2.2.15 cell lines, but no antiviral action against HBV.     

初乳、常乳及其制品中的雌性激素

简要介绍了人和牛初乳、常乳及其制品中天然雌性激素的种类、结构、含量、存在状态,并讨论了常规乳品加工对不同雌性激素的影响.     

制造高档牛皮擦色革的技术关键

介绍了高档牛皮擦色革在生产中的一些技术关键和技术难点。通过笔者的亲身实践,创新地设计开发了一种不同于传统擦色革效应层加工技术。     

Thromboelastography in healthy dairy cows

Thromboelastography is a whole blood-based coagulation assay that can be used to investigate hypocoagulability and hypercoagulability, as seen with thromboembolic diseases and disseminated intravascular coagulation. Numerous coagulopathies due to different causes are reported in cows. The objective was to establish reference intervals for thromboelastography using the TEG 5000 (Haemonetics GmbH, Munich, Germany) with citrated whole blood samples and kaolin activation in dairy cows and to investigate possible thromboelastographic changes between cows in different lactation periods. An additional objective was to test the stability of samples for up to 100 h. Sixty blood samples from healthy Holstein-Friesian cows were examined. The samples were allocated to 3 different lactation groups (≤30 d postcalving, 31–99 d postcalving, ≥100 d postcalving). Thromboelastography was performed by using the TEG 5000 analyzer with citrated whole blood samples with kaolin activation. The calculated reference intervals were as follows: reaction time = 2.2 to 6.2 min, coagulation time = 0.8 to 2.0 min, angle α = 58.2 to 81.8°, maximum amplitude = 64.3 to 89.2 mm, and clot rigidity = 9.2 to 41.2 dyn/cm². The 3 different lactation groups showed no significant differences in TEG parameters. No significant difference was seen in samples stored for up to 48 h at room temperature, which indicates that delays in processing samples, such as those arising during transit, are not an issue.     

Molecular Epidemiology and Population Structure of Bovine Streptococcus uberis

The molecular epidemiology and population structure of 30 bovine subclinical mastitis field isolates of Streptococcus uberis, collected from 6 Portuguese herds (among 12 farms screened) during 2002 and 2003, were examined by using pulsed-field gel electrophoresis (PFGE) for clustering of the isolates and multilocus sequence typing (MLST) to assess the relationship between PFGE patterns and to identify genetic lineages. The 30 isolates were clustered into 18 PFGE types, using a similarity cutoff of 80%, and 3 PFGE types accounted for almost half of the isolates (46.6%). These major types were herd specific, suggesting either cow-to-cow transmission or infection with isolates from the same environmental reservoirs. The remaining unrelated PFGE types of isolates were from different herds strongly suggesting environmental sources of Strep. uberis infection. All 30 isolates were analyzed by MLST and clustered into 14 sequence types (ST). These ST were found to be novel, either with 10 new alleles of 6 housekeeping genes or with different combinations of previously assigned alleles. Five of these ST were clustered into 3 clonal complexes (lineages), ST-143, ST-86, and ST-5, known to include bovine isolates from several geographic locations (Australia, New Zealand, United Kingdom, Sweden, and Denmark) and 9 singletons. To our knowledge, this is the first report that documents molecular typing studies of bovine isolates of Strep. uberis from Portugal, which were shown to represent novel genomic backgrounds of this pathogen.     

牛蒡抗氧化、降血脂保健功能研究

利用大白鼠进行动物实验,研究牛蒡的抗氧化、降血脂保健作用.结果表明:牛蒡能显著降低高血脂大鼠的血清总胆固醇、甘油三酯和低密度脂蛋白水平,减小动脉硬化指标,对大白鼠高脂血症和动脉硬化具有胶玫脑し雷饔?牛蒡还能显著降低高血脂大鼠的肝系数、肝脏总胆固醇和甘油三酯水平,缓解肝脏的脂肪病变;牛蒡能提高大鼠红细胞内SOD活力、降低红细胞中MDA含量、提高血液中GSH-Px活力,从而清除机体内的超氧阴离子,减少机体受自由基的攻击.     

Identification of ubiquitin in bovine milk and its growth inhibitory effects on human cancer cell lines

Bovine milk is associated with improved health and reduced risk of several diseases, among them cancer. Milk is a complex mixture of known and unknown components. The components and the mechanisms that contribute to the cancer-preventive effects are largely unknown. We set out to find new peptides in milk and identified ubiquitin (Ub) using matrix-assisted laser desorption ionization-time of flight mass spectrometry and Western blot. Using quantitative Western blot, we estimated the Ub concentration to be about 0.003 μmol/L in milk. We then decided to investigate the effect of treating human colon cancer CaCo-2 cells with Ub, using higher concentrations than in milk. CaCo-2 cells treated with 0.02 to 2.0 μmol/L Ub showed significantly decreased proliferation compared with untreated control cells. A higher growth inhibitory effect than in CaCo-2 cells was found in the neuroblastoma cell line SH-SY5Y treated with 0.02 to 0.2 μmol/L Ub. A bromodeoxyuridine DNA flow cytometric method was used to study cell cycle kinetics in Ub-treated CaCo-2 cells. The data point toward a prolongation of the G₁ phase. The levels of several cell cycle regulatory proteins were affected. Our data point to Ub possibly being one of the components in milk reducing the risk of cancer.