Energetic irrelevance of aerobiosis for S. cerevisiae growing on sugars

Summary The net benefit that Saccharomyces cerevisiae obtains from aerobiosis as compared to anaerobiosis has been studied. For this purpose yeasts with different respiratory capacities have been obtained by growing them in batch cultures on different substrates. Even with sugars with low catabolite repression effect, as is the case of galactose, aerobiosis increased the growth rate and the growth yield by less than two-fold. These variations, which are much lower than the expected considering the actual oxygen utilization, indicate that either the amount of ATP produced in respiration is much lower than the theoretically expected or a much greater expenditure of ATP occurs in aerobic than in anaerobic growth. The results show that S. cerevisiae obtains only a slight benefit from aerobiosis when growing on sugars at the relatively high concentration prevailing in its natural habitats.The inhibition of sugar consumption rate by aerobiosis (Pasteur effect) has also been studied, Pasteur effect was almost unnoticeable during growth on any tested sugar and very low during ammonia starvation. These results contrast with the general belief that Pasteur effect is a quantitatively important phenomenon in yeast. It is concluded that the relevant observations of Louis Pasteur have little relationship with the phenomenon that bears his name.     

The brain-derived neurotrophic factor Val66Met polymorphism modulates the effects of parental rearing on personality traits in healthy subjects

There is a growing body of data suggesting that gene-environment interaction is critical in the characterization of personality traits; however, previous studies have not taken into consideration variability in parental rearing as an environmental factor. In this study, we examined the effects of the interaction between the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism and parental rearing on personality traits in 710 healthy Japanese subjects. Perceived parental rearing was assessed by the Parental Bonding Instrument (PBI), which consists of the care and protection factors. Assessment of personality traits was performed by the temperament and character inventory (TCI), which has seven dimensions, i.e. novelty seeking, harm avoidance, reward dependence, persistence, self-directedness, cooperativeness and self-transcendence. Parental rearing has significant main effects on some TCI dimensions, but no significant main effects of the BDNF genotype on the TCI scores were found. The interaction between the BDNF genotype and maternal care of the PBI had significant effects on harm avoidance and self-directedness of the TCI. Post hoc analyses showed that decreased maternal care was correlated with increased harm avoidance and decreased self-directedness, and for both personality traits the partial correlation coefficient was highest in the Met/Met genotype group and lowest in the Val/Val genotype group and the value of the Val/Met genotype group was in the middle. Data from this study suggest that the BDNF Val66Met polymorphism modulates the effects of parental rearing, especially maternal care, on harm avoidance and self-directedness in healthy subjects.     

黄曲条跳甲人工饲养技术改进

通过室内人工饲养建立实验种群,是开展黄曲条跳甲Phyllotreta striolata(Fabricius)各种研究的基础,解决其幼虫阶段的人工饲养技术是建立其实验种群的关键。介绍经改进后的黄曲条跳甲室内人工饲养技术,该方法简单易行,可以方便地获取试虫的不同虫态;采用"小菜苗法"和"萝卜薄片堆叠法"室内饲养黄曲条跳甲幼虫,最高存活率可达90%以上。     

Verification of daily growth increment formation in saury otoliths by rearing larvae from hatching

Naturally spawned eggs of the Pacific saury,Cololabis saira, were collected in the field and reared in a tank to examine daily periodicity of growth increment formation in the otolith. Larvae were 6.9 mm in knob length at hatching. Their otoliths (sagittae) were 31 μm in radius and had 3–6 faint concentric rings. They started feeding within two days and grew at a rate of 1.1 mm/day on average through larval and juvenile stages feeding on rotifers,Artemia nauplii, and artificial diets. Otolith growth increments showed a concentric pattern with a distance of 3.5–5.0 μm between two adjacent increments. The number of growth increments was almost equal to a known age in days plus 4 or 5. A regression line of number of increments (N) on known age in days (D) between 0–30 days after hatching was N = 4.81 + 1.01D, which shows that one increment was deposited per day.     

Influence of parents' eating behaviors and child feeding practices on children's weight status

Objective : To investigate the effects of mothers’ and fathers’ eating behaviors, child feeding practices, and BMI on percentage body fat and BMI in their children. Research Methods and Procedures : Four hundred fifty‐eight parents (239 mothers, 219 fathers) were asked to complete two questionnaires: the Three‐Factor Eating Questionnaire and the Child Feeding Questionnaire, which measure dimensions of parent eating behavior and child feeding practices, respectively. Parent BMI was calculated from self‐reported height and weight; children's measures included BMI and percentage fat assessed by DXA. Regression analyses were used to analyze relationships between parents’ BMI and questionnaire scores and children's weight status. Results : One hundred forty‐three mothers and 68 fathers returned questionnaires, representing parents of 148 children 3 to 5 years old (78 boys). Children's weight was related to mothers’ BMI, but not fathers’. Girls had a greater BMI if either parent reported being overweight as a child, and both girls and boys were likely to be overweight if their mothers believed they had risky eating habits (fussiness, eating too much, etc.). Girls with fathers who were more controlling had a higher percentage fat; these fathers were also more concerned about their daughters’ future health. Discussion : Mothers exert a strong influence over their children's weight and seem to be more concerned about their children's eating behaviors; however, fathers play a role in imposing child feeding practices. Gender bias may be present in child feeding, as suggested by dissimilar effects of parent practices on the weight status of girls vs. boys. Fathers should be included in future studies analyzing parent feeding practices and children's weight outcome.     

Infant feeding practices and chronic child malnutrition in the Indian states of Karnataka and Uttar Pradesh

As measured by degree of stunting, close to half of India's children suffer from chronic malnutrition and about a quarter from severe chronic malnutrition. Data from the 1998-1999 National Family Health Survey (NFHS) are analysed to assess whether recommended infant feeding practices help to alleviate the prevalence of stunting. The evidence supports some recommended practices, including the advice that mother not squeeze the colostrum from her breasts, not use a feeding bottle with a nipple, exclusive breastfeeding for the first 4-6 months and feeding supplementary foods (solids and mushy foods) at about 7 months, and suggests that, for some children, better feeding practices could reduce the prevalence of severe stunting by up to 30%. The paper also examines a range of other issues related to stunting--whether medical supplementations and inoculations have an effect, whether mothers more actively involved in health decisions have less stunted children, and the links between stunting, diarrhoea and anaemia. An explanation is offered for the positive relationship between using oral rehydration salts and stunting.     

棉蚜饲养技术——笼罩法

在长期的试虫饲养过程中 ,摸索出一种新的棉蚜饲养方法———笼罩法。利用A4幅面的透明胶片和纱网制成笼罩。并于室内催芽 ,培育棉花种苗 ,可利用自制笼罩于光照培养箱内隔离饲养棉蚜 ,经与琼脂叶片法和自制Blackmanbox方法比较 ,笼罩法具有省时省力、不受季节限制、棉蚜生长条件好以及取食活体植株等许多突出的优点。     

On the potential use of echocardiography for assessing the formation of alcoholic cardiomyopathy

Chronic alcohol abuse not only leads to significant human psychic and social degradation, but also promotes the formation of alcoholic cardiomyopathy, which is one of the leading causes of high mortality of alcoholics. However, to date, there are no unified approaches in the prevention and treatment of alcoholic cardiomyopathy in clinics, primarily due to the lack of an adequate model in experimental pharmacology that could assess the stages of the formation of alcoholic cardiomyopathy objectively in real time, and thereby create the basis for the search and study of the mechanisms of action of drugs for the treatment of this serious disease. Studying the possibility of the use of echocardiography in experiments on rats with prolonged forced alcoholism is one of the approaches to solve this problem. It was shown that significant changes in intracardiac echocardiography hemodynamics corresponding to that known from the clinics begin to form from the 20th week of systematic consumption of alcohol by rats. By this time, the reduction in inotropic function of the heart in alcoholized rats compared to control rats is observed: the shortening fraction (SF) is 41.9% (40.3–42.2) and 51.3% (48.8–59.1), respectively, and the ejection fraction (EF) is 78.8% (77.4–79.2) and 87.5% (84.6–92.4), respectively, p ≈ 0.0215. The dilated heart failure develops in rats from the 24th week of regular alcohol consumption, as illustrated not only by the dynamic reduction of SF and EF, but also by the dilatation of the heart. For example, the end-systolic dimension of the left ventricle in animals consuming alcohol compared with the control rats more than doubled (4.31 mm (3.80–4.41) and 2.0 mm (1.85–2.36), p ≈ 0.0008, and the end-diastolic dimension was 5.95 mm (5.13–6.37) and 4.52 mm (3.85–4.90), respectively; p ≈ 0.0171. Thus, the echocardiographic picture characteristic of alcoholic dilated cardiomyopathy is formed by the end of the 24th week of chronic alcoholization.     

On the requirement of oxidizing reagent for the formation of a disulfide bond

Cyclization of a peptide through the formation of a disulfide bond between the SH groups of cysteines on the N- and C-terminals of peptide was studied in degassed water solution under vacuum. Cyclization went to completion although the solution was oxygen deficient (the number of oxygen molecules available for the reaction was at least 16 times less than the number of peptide molecules). This result indicates that, contrary to the common assumption, disulfide bond formation does not necessarily require an oxidant (O(2), I(2), etc.) to occur.     

On the statistical thermodynamics of membrane formation

Modifying a procedure developed by Scheutjens and Fleer (J. Phys. Chem. 83 (1979) 1619: J. Phys. Chem. 84 (1980) 178) to describe adsorption of polymers, a lattice theory is proposed to formulate the formation and properties of amphiphilic bilayer membranes. In this theory individual conformations are distinguished and lateral interactions are taken into account in a Flory-Huggins approximation. Probability distributions of head tail and solvent segments are computed and it is shown that they are not narrow, i.e., membrane properties are subject to considerable fluctuations. The average concentration of the water in the hydrophobic core is nonzero. Various extensions, consequences and applications are proposed.