Development of Lactococcus lactis encoding fluorescent proteins,GFP, mCherry and iRFP regulated by the nisin-controlled gene expression system

Fluorescent proteins are useful reporter molecules for a variety of biological systems. We present an alternative strategy for cloning reporter genes that are regulated by the nisin-controlled gene expression (NICE) system. Lactoccocus lactis was genetically engineered to express green fluorescent protein (GFP), mCherry or near-infrared fluorescent protein (iRFP). The reporter gene sequences were optimized to be expressed by L. lactis using inducible promoter pNis within the pNZ8048 vector. Expression of constructions that carry mCherry or GFP was observed by fluorescence microscopy 2 h after induction with nisin. Expression of iRFP was evaluated at 700 nm using an infrared scanner; cultures induced for 6 h showed greater iRFP expression than non-induced cultures or those expressing GFP. We demonstrated that L. lactis can express efficiently GFP, mCherry and iRFP fluorescent proteins using an inducible expression system. These strains will be useful for live cell imaging studies in vitro or for imaging studies in vivo in the case of iRFP.     

Flower and fruit abortion in sweet pepper in relation to source and sink strength

Source strength (assimilate supply) and sink strength (assimilate demand) of the plant were varied in different ways to investigate to what extent flower/fruit abortion in sweet pepper (Capsicum annuum L.) is determined by the availability of assimilates. Source strength was varied by changing the light level, plant density, and leaf pruning. Sink strength was varied by changing the temperature and the number and position of earlier formed fruits. Shading as well as heating for short periods showed that flowers/fruits were the most susceptible to abortion during the first week after anthesis. The different experiments where source strength was varied all showed that when source strength decreased, the rate of abortion increased linearly, whether source strength was decreased by shading, high plant density, or leaf pruning. That flower and fruit abortion not only depends on the source strength but also on the sink strength of competing organs is shown by varying the number or the position of earlier formed fruits. With the same source strength, the rate of abortion showed a close relationship with the growth rate of the earlier formed competing fruits, suggesting that the induction of abortion by earlier formed fruits is due to their sink strength. Most of the variation in abortion could be related to differences in vegetative growth rate, the latter being an indicator of the source-sink ratio. However, with the same vegetative growth rate, the rate of abortion was lower for the leaf pruning treatments where no competing fruits were retained than for the fruit load treatments. This indicates that although most of the variation in abortion can be related to the source and sink strength of the plant, some effects of competing fruits can only be explained by a combination of competition and dominance.     

Apolipoprotein C3 SstI polymorphism and triglyceride levels in Asian Indians

Background  

A close association between Sst I polymorphism in the 3' untranslated region of the apolipoproteinC3 (APOC3 ) gene and levels of plasma triglycerides (TG) had been reported by different investigators. Hypertriglyceridemia(HTG) is a known risk factor for coronary artery disease (CAD) in the context of Asian Indians. We conducted a study on the relationship between APOC3 SstI polymorphism (S1S1, S1S2 and S2S2 genotypes) and plasma TG levels in a group of 139 male healthy volunteers from Northern India.     

混合线性模型下猪群间遗传联系的度量

采用关联指数(IC)和决定系数(CD)两种方法,度量混合线性模型遗传评估下 猪群体间的遗传关联性。结果表明,加拿大安大略省的大约克夏猪、长白猪、杜洛克猪和汉普夏猪4个主要品种群体间具有良好的遗传联系。CD法既组合了数据结构和信息量,又考虑了预测误差方差和遗传变异性,是一个选择判断遗传评估精度的好方法。 Abstract:Two criteria for the measures of genetic connectedness in mixed linear model of genetic evaluation are used:the degree of connectedness(IC)and the generalized coefficient of determination(CD).The results indicated that the data of four dominant swine breeds:Yorkshire,Landrace,Duroc and Hampshire in Ontario,Canada are well connected.The CD,which combines data structure and amount of information and also accounts for both prediction error variance and genetic variability,is a good method to select for judging the precision of a genetic evaluation.     

The many roles of small RNAs in leaf development

Leaf development involves many complex genetic interactions,signals between adjacent cells or between more distant tissues and consequent changes in cell fate.This review describes three stages in leaf development where regulation by small RNAs have been used to modulate gene expression patterns.     

Factors affecting the accuracy of urine-based biomarkers of BSE

Background  

Transmissible spongiform encephalopathy diseases are untreatable, uniformly fatal degenerative syndromes of the central nervous system that can be transmitted both within as well as between species. The bovine spongiform encephalopathy (BSE) epidemic and the emergence of a new human variant of Creutzfeldt-Jakob disease (vCJD), have profoundly influenced beef production processes as well as blood donation and surgical procedures. Simple, robust and cost effective diagnostic screening and surveillance tools are needed for both the preclinical and clinical stages of TSE disease in order to minimize both the economic costs and zoonotic risk of BSE and to further reduce the risk of secondary vCJD.     

Evaluation of zona pellucida birefringence intensity during in vitro maturation of oocytes from stimulated cycles

Background  

This study evaluated whether there is a relationship between the zona pellucida birefringence (ZP-BF) intensity and the nuclear (NM) and cytoplasmic (CM) in vitro maturation of human oocytes from stimulated cycles.     

Motile sperm organelle morphology examination (MSOME): intervariation study of normal sperm and sperm with large nuclear vacuoles

Background  

Although the motile sperm organelle morphology examination (MSOME) was developed only as a selection criterion, its application as a method for classifying sperm morphology may represent an improvement in evaluation of semen quality, with potential clinical repercussions. The present study aimed to evaluate individual variations in the motile sperm organelle morphology examination (MSOME) analysis after a time interval.