碘的安全摄入量范围研究进展

动物实验表明,短期或长期高碘摄入会对机体产生一定的毒性,包括发育毒性、遗传毒性和致畸性等。目前世界各国家及组织对于碘的推荐摄入量（reference nutrition intake,RNI）和可耐受最高摄入量（tolerable upper intake level,UL）的制定一般是基于一些的人体实验研究和人群调查,但由于地理环境及人种差异等原因,所得数据并不统一。由于参照的研究数据不同,各国对不同人群设定的碘安全摄入量参照标准也不尽相同。鉴于此,分析了国际上主要的国家及国际组织制订标准的过程与依据,概述了我国相关标准的制订过程与依据以及El前的研究进展,明确了进一步探讨和研究更适合我国人群的碘的安全摄入量是当前和今后的工作重点之一,也是食盐加碘计划（universal salt iodization,USI）科学实施的重要保障。     

How NOT to Approach the Obesity Problem

FLATT, JP. How NOT to approach the obesity problem. The emphasis given to the energy balance equation has fostered the widespread belief that obesity is a problem of energy balance. This mistaken view has led to many unjustified and unfortunate interpretations, because obesity is, rather, a problem of the interaction between body composition and food intake regulation.     

An Approach to Quantitative Nutrition of Phytoplankton

SYNOPSIS. An outline is given of the 2-compartment model of algal growth developed by the author over the last decade, The model, as fully developed, claims to be able to handle simultaneously as many nutrients and organisms as desired in an environment of changing inputs and outputs.     

Allelic frequencies and statistical data obtained from 12 codis STR loci in an admixed population of the Brazilian Amazon

The allelic frequencies of 12 short tandem repeat loci were obtained from a sample of 307 unrelated individuals living in Macapá, a city in the northern Amazon region, Brazil. These loci are the most commonly used in forensics and paternity testing. Based on the allele frequency obtained for the population of Macapá, we estimated an interethnic admixture for the three parental groups (European, Native American and African) of, respectively, 46%, 35% and 19%. Comparing these allele frequencies with those of other Brazilian populations and of the Iberian Peninsula population, no significant distances were observed. The interpopulation genetic distances (F(ST) coefficients) to the present database ranged from F(ST) = 0.0016 between Macapá and Belém to F(ST) = 0.0036 between Macapá and the Iberian Peninsula.     

生态系统的人口承载力理论初探

人口膨涨是当今人类面临的五大问题之一,也是我国目前所面临的最棘手的一个问题。近年来,人口学的发展很快,但是目前人口学研究的主要问题是人口统计、人口预测、人口控制和人口经济等方面,其中对于人口控制的目标,即定量研究理想人口数量的工作则刚开始。从生态学角度讨论人口承载力问题的更少。生态系统人口承载力的研究不仅可以给出一个生态系统(如全球生态系统或一个流域或一个地区)在保证系统结构和功能不受破坏条件下所能供养的最大人口数,而且可以给出该生态系统的人口控制目标,使人口控制的目标选择具有科学的基础。     

Digital dermatoglyphic patterns in a sample of the Nigerian population

Eight hundred Nigerians (400 males and 400 females) were screened for the analysis of digital dermatoglyphic patterns. The frequency distribution of the patterns are 52.09%, 27.67%, 19.20% and 1.13% for ulnar loops, whorls, arches and radial loops respectively. Except for arches, the males have more of the patterns than females. The pattern intensity indices for males and females are 11.2 and 9.9 respectively. Bilateral symmetry is similar in both sexes and the percent distribution is as high as 81.5% and 84% on digit V in males and females respectively.     

An Experimental Approach to the Effects of Predictability on Community Structure

This paper considers the effects of different levels of resourcepredictability on niche widths, competition and diversity ina community of three hummingbird species. Three pairs of hypothesesare tested: whether decreasing predictability (a) increasesor decreases niche width, (b) increases or decreases competitionand (c) increases or decreases diversity. The results show thatcomplementary increases and decreases in niche width occur withdecreasing predictability, while competition and diversity decrease,at least with extreme unpredictability. A model, which assumesthe species to have similar resource preferences, and its predictionsare examined. The dominant species, Lampornis clemenciae, excludes a subordinatespecies, Archilochus alexandri, from preferred resources. Thisdefense becomes unprofitable with decreasing predictabilityand Archilochus invades the resources once vigorously defendedby Lampornis. When the spectrum of resources is altered in thedirection of decreasing suitability for both species, Lampornisbecomes even more specialized and sensitive to the effects ofunpredictability. A third species, Eugenes fulgens, steals resourcesundefended by Lampornis. These characteristics seem to be commonto a number of communities in very different taxonomic groups,and characteristic of communities in which species share a commonpreferred resource. The question of how a community organizedwith distinct resource preferences responds to decreasing predictabilityremains open.     

Isoelectric subtyping of the PGM1 in the Icelandic population

Phenotypes for the red blood cell enzyme phosphoglucomutase (PGM1) were determined by isoelectric focusing for a population of 2,501 Icelandic individuals. All ten phenotypes were observed, and the frequencies of four alleles at the PGM1 locus were as follows: PGM1 1+=0.6875; PGM1 1−=0.1124; PGM1 2+=0.1419, and PGM1 2−=0.0582. These results have been compared with those found in other northern European populations.     

Blood group and protein polymorphism gene frequencies for seven breeds of horses in the United States

Gene frequencies at 20 blood group and protein polymorphism loci ( A, C, D, K, P, Q, U, Al, Tf, Pi, Xk, Es, Gc, PGD, CA, Cat, PGM, AP, Hb and PHI ) are given for seven horse breeds in the United States (Thoroughbred, Arabian, Standard bred, Morgan, Quarter Horse, Paso Fino and Peruvian Paso). These data are used to calculate that the battery of tests is at least 96% effective for recognizing incorrect paternity in these breeds. In addition to paternity testing, these tests can be applied to studies of breed relationships.     

Characterization of the Microbial Community in Indoor Environments: a Chemical-Analytical Approach

An integrated procedure is presented whereby gas chromatography-ion trap mass spectrometry is used to determine chemical markers of gram-negative bacterial lipopolysaccharide (3-hydroxy fatty acids with 10 to 18 carbon atoms), gram-positive bacteria (branched-chain fatty acids with 15 and 17 carbon atoms), bacterial peptidoglycan (muramic acid), and fungal biomass (ergosterol) in samples of settled house dust. A hydrolysate of ¹³C-labeled cyanobacterial cells is used as an internal standard for the first three markers. These analyses require two dust samples, one for 3-OH fatty acids, branched-chain fatty acids, and muramic acid and another for ergosterol. The method may be used to characterize microbial communities in environmental samples.     

Enzyme Production-Based Approach for Determining the Functions of Microorganisms within a Community

The functions of specific microorganisms in a microbial community were investigated during the composting process. Cerasibacillus quisquiliarum strain BLx^T and Bacillus thermoamylovorans strain BTa were isolated and characterized in our previous studies based on their dominance in the composting system. Strain BLx^T degrades gelatin, while strain BTa degrades starch. We hypothesized that these strains play roles in gelatinase and amylase production, respectively. The relationship between changes in the abundance ratios of each strain and those of each enzyme activity during the composting process was examined to address this hypothesis. The increase in gelatinase activity in the compost followed a dramatic increase in the abundance ratio of strain BLx^T. Zymograph analysis demonstrated that the pattern of active gelatinase bands from strain BLx^T was similar to that from the compost. Gelatinases from both BLx^T and compost were partially purified and compared. Homologous N-terminal amino acid sequences were found in one of the gelatinases from strain BLx^T and that of compost. These results indicate strain BLx^T produces gelatinases during the composting process. Meanwhile, the increase in the abundance ratio of strain BTa was not concurrent with that of amylase activity in the compost. Moreover, the amylase activity pattern of strain BTa on the zymogram was different from that of the compost sample. These results imply that strain BTa may not produce amylases during the composting process. To our knowledge, this is the first report demonstrating that the function of a specific microorganism is directly linked to a function in the community, as determined by culture-independent and enzyme-level approaches.     

Assessment of a Novel Approach to Identify Trichiasis Cases Using Community Treatment Assistants in Tanzania

Background

Simple surgical intervention advocated by the World Health Organization can alleviate trachomatous trichiasis (TT) and prevent subsequent blindness. A large backlog of TT cases remain unidentified and untreated. To increase identification and referral of TT cases, a novel approach using standard screening questions, a card, and simple training for Community Treatment Assistants (CTAs) to use during Mass Drug Administration (MDA) was developed and evaluated in Kongwa District, a trachoma-endemic area of central Tanzania.

Methodology/Principal Findings

A community randomized trial was conducted in 36 communities during MDA. CTAs in intervention villages received an additional half-day of training and a TT screening card in addition to the training received by CTAs in villages assigned to usual care. All MDA participants 15 years and older were screened for TT, and senior TT graders confirmed case status by evaluating all screened-positive cases. A random sample of those screened negative for TT and those who did not present at MDA were also evaluated by the master graders. Intervention CTAs identified 5.6 times as many cases (n = 50) as those assigned to usual care (n = 9, p < 0.05). While specificity was above 90% for both groups, the sensitivity for the novel screening tool was 31.2% compared to 5.6% for the usual care group (p < 0.05).

Conclusions/Significance

CTAs appear to be viable resources for the identification of TT cases. Additional training and use of a TT screening card significantly increased the ability of CTAs to recognize and refer TT cases during MDA; however, further efforts are needed to improve case detection and reduce the number of false positive cases.     

Response of the Sulfate-Reducing Community to the Re-establishment of Estuarine Conditions in Two Contrasting Soils: a Mesocosm Approach

We studied the response of the sulfate-reducing prokaryote (SRP) communities to the experimental variation of salinity and tide in an outdoor mesocosm setup. Intact soil monoliths were collected at two areas of the Haringvliet lagoon (The Netherlands): one sampling location consisted of agricultural grassland, drained and fertilized for at least the last century; the other of a freshwater marshland with more recent sea influence. Two factors, i.e., “salinity” (freshwater/oligohaline) and “tide” (nontidal/tidal), were tested in a full-factorial design. Soil samples were collected after 5 months (June–October). Dissimilatory (bi)sulfite reductase β subunit-based denaturing gradient gel electrophoresis (dsrB-DGGE) analysis revealed that the SRP community composition in the agricultural grassland and in the freshwater marshland was represented mainly by microorganisms related to the Desulfobulbaceae and the Desulfobacteraceae, respectively. Desulfovibrio-related dsrB were detected only in the tidal treatments; Desulfomonile-related dsrB occurrence was related to the presence of oligohaline conditions. Treatments did have an effect on the overall SRP community composition of both soils, but not on the sulfate depletion rates in sulfate-amended anoxic slurry incubations. However, initiation of sulfate reduction upon sulfate addition was clearly different between the two soils.     

Community seed rain patterns and a comparison to adult community structure in a West African tropical forest

We examined the seed rain throughout a twelve month period in a lowlandtropical forest in Cameroon, West Africa, 1996–97. Traps (0.5m², n = 216) were erected throughout a 25km² area in 24 randomly placed clusters of nine trapseach. Fruits and seeds that landed in traps were collected every 7–10daysand classified by species and dispersal type. More than 32,000 seeds fromapproximately 200 species fell into the traps, an average of 297 seedsm^–2 yr^–1 Thirty species represent 82%of the total seed rain while an additional 175 species comprise the remaining18%. When we compared the adult community to the seed rain community within thesame plots, we found no apparent correlation between seed rain patterns andadult community structure for this year of study. Furthermore, only 49% of theadult tree community produced and dispersed seed into traps in this year. Morethan 100 species (52%) found in the seed rain represented long-distanceimmigrant seed rain. Seed rain was highly variable at several scales, bothspatially and seasonally, although seeds arrived in traps during eachcollectionperiod. Cluster analyses showed that traps within plots were seldom moresimilarto one another than traps between plots. While 82% of the tree species in thecommunity are thought to be animal dispersed, only 28% of all seeds that fellinto traps had been obviously handled (bitten, chewed, or passed)by animals. Tests for fruit and seed removal by predators or dispersers found5%or less removal rate from traps.     

The Role of Remarriage in a Microevolutionary Process: Considerations from a 19th-Century Italian Community

In this study, we investigate the extent to which social norms and cultural constraints might affect the genetic contribution of remarriage to future generations in a mid–19th century Italian population. By reconstructing the life histories of the inhabitants of Casalguidi, 1,028 marriages were recorded and analyzed. Frequency and reproductive pattern of remarriages were found to play a quantitatively important role in the process of population renewal, featuring 20 percent of total unions and 12 percent of total children borne between 1820–58. Cultural patterns shaped the access to remarriage, but widows resulted more open than widowers in the partner choice. Furthermore, remarriages were more likely consanguineous than first unions because of socioeconomic reasons. As a result, a genotypic differentiation between the offspring of first marriage and remarriage was found. However, the lower intensity of female remarriage and the predominance of widowers' unions limited the potential differentiation in the gene pool of offspring.     

Twelve years after: Child development as related to social,nutritional and cultural changes in the Czech Republic

Modifications of social, political, cultural, nutritional and behavioral factors in the Czech Republic during the nineties were not homogeneous, and/or of the same rate and character; however, the effect on child population was manifested. In all former socialist countries social contrasts have increased along with the modifications of the availability of the foodstuffs and changes in food preferences and aversions. In this respect, new commercials and advertising play an important role. Modifications of spontaneous food selection have effects on the development of children, which is already apparent in early age. Body Mass Index of Czech children, which used to be higher than that of Western Europe, has not change since the end of the eighties, and is now nearly identical to them. Prevalence of serious obesity in children, its treatment and prevention has become a more urgent health problem. The level of physical fitness in Czech children on the average tends to decrease, and is more divergent and its lower level in normal hypo-kinetic youth contrasts with small groups of growing subjects involved in certain sport disciplines in which training starts early (e.g. gymnastics, tennis, figure skating etc.).     

Novel Approach to Quantitative Detection of Specific rRNA in a Microbial Community, Using Catalytic DNA

We developed a novel method for the quantitative detection of the 16S rRNA of a specific bacterial species in the microbial community by using deoxyribozyme (DNAzyme), which possesses the catalytic function to cleave RNA in a sequence-specific manner. A mixture of heterogeneous 16S rRNA containing the target 16S rRNA was incubated with a species-specific DNAzyme. The cleaved target 16S rRNA was separated from the intact 16S rRNA by electrophoresis, and then their amounts were compared for the quantitative detection of target 16S rRNA. This method was used to determine the abundance of the 16S rRNA of a filamentous bacterium, Sphaerotilus natans, in activated sludge, which is a microbial mixture used in wastewater treatment systems. The result indicated that this DNAzyme-based approach would be applicable to actual microbial communities.     

A New Approach for the Modelling of Sediment Reworking Induced by a Macrobenthic Community

A new model of bioturbation has been developed to describe short term sediment reworking induced by macrobenthic communities. The design of the model had to consider the mixing processes, firstly, at the organism level, and secondly, at community level. This paper describes the mixing mode of the four types of bioturbators defined by the authors: the biodiffusors, the upward-conveyors, the downward-conveyors and the regenerators. The mathematical formulation of these sub-models consists of ordinary differential equations. They take into account the size of the bioturbated zone, the output fluxes to the water column, tracer decay, physical mixing due to local currents and the type and intensity of the bioturbation processes. These sub-models make it possible to describe correctly the mixing events that have occurred in cores with each type of bioturbator. They also provide the basis for general bioturbation model, that will take into account the respective degrees of involvement of (i) the different bioturbation processes and their characteristics, (ii) the interference between the different processes, and (iii) make possible to predict the particle reworking in order to include it in studies of organic matter in early diagenesis. This revised version was published online in June 2006 with corrections to the Cover Date.