2013 Vol. 26, No. 9
In dairy and food industries lactic acid bacteria (LAB) have been used in form of starter culture that plays vital role in fermentation;as flavouring and texturizing or as preservative agents.There is increasing evidence that lactobacilli which inhabit the gastrointestinal tract develop antimicrobial activities and participate in the host's defence system.During fermentation,most of the LAB produces a number of different compounds like organic acids,hydrogen peroxide,diacetyl,acetaldehyde,carbon dioxide,polysaccharides,and proteinaceous compounds called bacteriocins or bacteriocinogenic peptides[2-3].
Obesity,one of the most common health problems,is associated with glucose and lipid metabolism abnormalities,increased cardiovascular risk and oxidative stress.Aging is also associated with an increase in oxidative stress.Considering that older adults are already at risk for oxidant stress,the additional metabolic perturbations of obesity aggravated the susceptibility to oxidant stress.Modulating age-related oxidative stress via dietary interventions could reduce free radical production and significantly improve health in aging.
Cadmium (Cd) is an elemental heavy metal with widely recognized toxicity.Its long-term use in industrial processes and daily activities has caused alarming levels of Cd contamination in the natural environment.According to the estimates by the Agency of Toxic Substances and Disease Registry in the US,25 000 to 30 000 metric tons of Cd is annually released to the environment.Results of previous studies have demonstrated that several organs are targets of Cd,but the most important of these targeted organs may be the testes.Cadmium can cause the apoptosis of testis cells and modify the expression of carcinogenesis-related genes to cause cancer in the testes,interfere with the male reproductive endocrine functions,or even alter gene expression at non-toxic doses.To date,the mechanism underlying the reproductive toxicity caused by Cd in male animals remains unclear.Here,the effect of Cd on primary cultures of Leydig cells was investigated in vitro.
The essential effect of vitamin A on immune function occurs through various mechanisms including direct effect on Th1-Th2 balance modulation.However,it is unclear whether or not vitamin A can regulate Th1-Th2 balance under a strong Th1-polarizing condition.Therefore,the purpose of our study was to examine the effect of vitamin A metabolite all-trans retinoic acid (ATRA)on Th1-Th2 differentiation in CD4+ T cells under GATA-3 deficiency,which can induce Th1-polarizing condition.In the present study,GATA-3 deficiency T cells were induced by siRNA and checked by real-time quantitative PCR and western blot.GATA-3 deficiency CD4+ T cells and normal CD4+ T were treated for 48 h with or without ATRA.The expression of Th1 and Th2 cytokines were detected by qPCR and ELISA.The results would contribute to clarify the knowledge of the role of vitamin A in regulating Th1-Th2 balance under some special conditions,and help to explain the mechanism of immune regulatory function of vitamin A.
Yersinia pestis is the causative agent of bubonic and pneumonic plagues.Strains of Y.pestis are classified into four biovars:antiqua,mediaevalis,orientalis,and microtus.There are two microtus-related plague foci in China:the Microtus brandti plague focus in the Xilin Gol Grassland (focus L) and the Microtus fuscus plague focus in the Qinghai-Tibet Plateau (focus M).
Group A streptococcus (GAS) causes a wide range of diseases in the human population.GAS diseases are more common in children than in adults,with clinical manifestations ranging from pharyngitis and impetigo to invasive infections and post streptococcal sequelae,such as acute rheumatic fever and acute post-streptococcal glomerulonephritis.GAS harbors a host of virulence factors that contribute to its complex pathogenicity and differences in the disease severity and frequency.M protein,one of the major virulence factors,is encoded by the emm gene induces a type of specific host immune response and confers antiphagocytic properties.