树鼩乳汁的主要成分检测及其意义

目的：探讨树鼩乳汁的基本成份,并和其它乳制品成份进行了比较分析。方法选取10只分娩后（1-21）d期间的哺乳期母树鼩,用人工被动母乳喂养方法让仔树鼩自由吮吸母乳,立即采用无菌操作的方法用注射器直接采取仔树鼩胃内的乳汁,1次／2 d,连续3-5次,每只母树鼩采取18 mL乳汁,按照国家标准的方法进行成分检测。结果树鼩乳汁总固形物为43.63％、脂肪为26.01％、蛋白质为10.41％、乳糖为0.45％、灰分为0.99％。树鼩乳的总固形物、灰分、蛋白质、脂肪、乳糖含量分别为牛乳的3.36、1.24、2.74、6.67、0.09倍;树鼩乳的总固形物、灰分、蛋白质、脂肪、乳糖含量分别为婴幼儿配方乳的1.44、0.20、0.58、1.53、0.06倍;与牛乳及婴幼儿配方乳矿物质成分含量相比,树鼩乳的矿物质成分钙、磷、钾、钠、镁、铁、锌含量均大于牛乳,分别为1.83、2.73、1.25、1.93、1.28、1.48倍,而均小于婴幼儿配方乳,分别为0.66、0.85、0.34、0.26、0.85、0.24、0.49倍。结论树鼩乳的主要营养成分呈现高脂高蛋白低糖的类型,可为树鼩人工育幼和饲养工作提供依据。     

Cronobacter species (formerly known as Enterobacter sakazakii) in powdered infant formula: a review of our current understanding of the biology of this bacterium

Cronobacter species (formerly known as Enterobacter sakazakii) are opportunistic pathogens that can cause necrotizing enterocolitis, bacteraemia and meningitis, predominantly in neonates. Infection in these vulnerable infants has been linked to the consumption of contaminated powdered infant formula (PIF). Considerable research has been undertaken on this organism in the past number of years which has enhanced our understanding of this neonatal pathogen leading to improvements in its control within the PIF production environment. The taxonomy of the organism resulted in the recognition of a new genus, Cronobacter, which consists of seven species. This paper presents an up-to-date review of our current knowledge of Cronobacter species. Taxonomy, genome sequencing, current detection protocols and epidemiology are all discussed. In addition, consideration is given to the control of this organism in the manufacturing environment, as a first step towards reducing the occurrence of this pathogen in PIF.     

Teasing apart the contributions of hard dietary items on 3D dental microtextures in primates

3D dental microtexture analysis is a powerful tool for reconstructing the diets of extinct primates. This method is based on the comparison of fossils with extant species of known diet. The diets of primates are highly diversified and include fruits, seeds, grass, tree leaves, bark, roots, tubers, and animal resources. Fruits remain the main component in the diets of most primates. We tested whether the proportion of fruit consumed is correlated with dental microtexture. Two methods of microtexture analysis, the scale-sensitive fractal analysis (SSFA) and the Dental Areal Surface Texture Analysis (DASTA; after ISO/FDIS 25178-2), were applied to specimens of eight primate species (Alouatta seniculus, Gorilla gorilla, Lophocebus albigena, Macaca fascicularis, Pan troglodytes, Papio cynocephalus, Pongo abelii, Theropithecus gelada). These species largely differ in the mean annual proportion of fruit (from 0 to 90%) in their diet, as well as in their consumption of other hard items (seeds, bark, and insect cuticles) and of abrasive plants. We find the complexity and heterogeneity of textures (SSFA) to correlate with the proportion of fruits consumed. Textural fill volume (SSFA) indicates the proportion of both fruits and other hard items processed. Furthermore, anisotropy (SSFA) relates to the consumption of abrasive plants like grass and other monocots. ISO parameters valley height, root mean square height, material volume, density of peaks, and closed hill and dale areas (DASTA) describe the functional interaction between food items and enamel facets during mastication. The shallow, plastic deformation of enamel surfaces induced by small hard particles, such as phytoliths or dust, results in flat microtexture relief, whereas the brittle, deep fracture caused by large hard items such as hard seeds creates larger relief.     

Antimicrobial resistance in Gram-negative bacilli isolated from infant formulas

A total of 90 samples of infant formula (IF) were collected from the lactary of a teaching hospital, during a 4-month period from July to August 1999. The sanitary conditions of the formulas were analyzed, and a physiological characterization of Gram-negative bacillus isolates and antimicrobial susceptibility testing were performed. Colony counts were considered to be unacceptable for the majority of the IF samples and the contamination rates were related to inadequate handling. Coliforms (35 degrees C and 45 degrees C growth) were detected in most of the IF tested. Klebsiella pneumoniae, Citrobacter freundii, Cedacea davisae, Klebsiella planticola and Enterobacter cloacae were the isolates most commonly identified. Antimicrobial susceptibility testing showed significant resistance rates, particularly to amoxicillin/clavulanic acid, cefoxitin, cephalotin or ampicillin. One extended-spectrum beta-lactamase-producing K. pneumoniae strain was also recovered.     

A new sampling formula for neutral biodiversity

The neutral model of biodiversity, proposed by Hubbell (The Unified Neutral Theory of Biodiversity and Biogeography, Princeton University Press, Princeton, NJ, 2001) to explain the diversity of functionally equivalent species, has been subject of hot debate in community ecology. Whereas Hubbell studied the model mostly by simulations, recently analytical treatments have yielded expressions of the expected number of species of a particular abundance in a local community with dispersal limitation. Moreover, a formula has been offered for the joint likelihood of observing a given species‐abundance dataset in a local community with dispersal limitation, but this formula is too complicated to allow practical applications. Here, I present a much simplified expression that can be regarded as an enhanced version of the famous Ewens sampling formula. It can be used in maximum likelihood methods for quick estimation of the model parameters, using all information in the data, and for model comparison. I also show how to rapidly generate examples of species‐abundance distributions for a given set of model parameters and how to calculate Simpson's diversity index.     

中国温带粒毛盘菌初探之一

报道了来自安徽与江西省的拉毛盘菌属8个分类单元,包括Lachnum abnorme,L ciliare,L.controvernm,L.lushanense,L.minutum,L.montanum,L.sclerotii var.sclerotii and L.virgineum。     

The IBD process along four chromosomes

In this note, we present the continuous-time Markov rate matrix that models identity by descent (ibd) patterns among four chromosomes in a population. The equilibrium distribution of this Markov process along a chromosome is the set of 4-gene state probabilities given by the Ewens sampling formula. This model will facilitate inference of identity by descent among the four chromosomes of a pair of individuals, using data at dense SNP loci among which there may be linkage disequilibrium.     

蒙古国喀尔喀部蒙古族4项群体指趾遗传学特征研究

在内蒙古民族大学调查了160例(男66例,女94例)来自蒙古国的喀尔喀蒙古族留学生的拇指类型、环食指长、指甲形状、足趾长4项群体指趾遗传学特征。研究结果:1)直型拇指率为44.38%,环指长率78.13%,指甲形状长型率58.75%、方型率6.88%、扁型率34.38%,足趾类型拇趾长率35.00%;2)指甲形状出现率性别间差异具统计学意义,两两特征间均未表现出明显相关关系;3)与我国10个蒙古族族群相比,多数差异具有统计学意义。     

The Effect of Breast‐Feeding with and without Formula Use on the Risk of Obesity at 4 Years of Age

Objective: To determine the minimal duration of breast‐feeding required to protect against later obesity, whether the concurrent use of formula lessened any protective effect of breast‐feeding, and what maternal or child characteristics might modify the association between breast‐feeding and child obesity. Research Methods and Procedures: This was a retrospective cohort study. Participants were 73, 458 white and black low‐income children followed from birth through 4 years of age. Obesity at age 4 years was defined as measured BMI ≥ 95th percentile. Feeding exposure was based on breast‐feeding duration and the age of formula initiation. Covariates were obtained from the children's birth certificates. Results: At age 4 years, the prevalence of obesity was 11.5%. Only 16% of children were breast‐fed 8 weeks or longer. Breast‐feeding was associated with a reduced risk of obesity only in white children whose mothers had not smoked in pregnancy. In this subgroup, the reduction in obesity risk (adjusted odds ratio, 95% confidence interval), compared with those never breast‐fed, occurred only for children who were breast‐fed at least 16 weeks without formula (0.71, 0.56 to 0.92) or at least 26 weeks with concurrent formula (0.70, 0.61 to 0.81). Among whites whose mothers smoked in pregnancy and among blacks, breast‐feeding was not associated with a reduced risk of obesity at age 4 years. Discussion: In a population of low‐income children, breast‐feeding was associated with a reduced risk of obesity at age 4 years only among whites whose mothers did not smoke in pregnancy and only when breast‐feeding continued for at least 16 weeks without formula or at least 26 weeks with formula.     

The Importance of Spatial Effects for Environmental Health Policy and Research

Issues of spatial scale and resolution are intrinsic to efforts aimed at protecting and improving environmental health. Deciding on an appropriate policy or selecting a suitable research design implies a decision, either implicit or explicit, about spatial scale and resolution. This article looks at issues in the context of environmental health, reviews crucial problems and questions, and examines examples of spatial effects on analytical results related to causal inference, disease clustering, and analysis and interpretation of census data. The discussion focuses on the need to consider spatial issues as a key component of informed, well- reasoned decisions about safeguarding environmental health.