布氏田鼠母体青春期捕食风险应激对后代反捕食行为和HPA轴基础活动水平的影响

本研究以28日龄的青春期雌性布氏田鼠作为亲代实验动物,每天分别暴露于蒸馏水、兔尿和猫尿60min,连续18d,成年后与正常雄鼠交配.随后检测其子代在28日龄(青春期)和90日龄(成年期)时暴露于这3种气味源的行为反应,以及下丘脑促肾上腺皮质激素释放激素、血浆促肾上腺皮质激素和皮质酮的基础水平.结果显示:与母体青春期暴露...     

Annual variation in maternal age and calving date generate cohort effects in moose (<Emphasis Type="Italic">Alces alces</Emphasis>) body mass

A general feature of the demography of large ungulates is that many demographic traits are dependent on female body mass at early ages. Thus, identifying the factors affecting body mass variation can give important mechanistic understanding of demographic processes. Here we relate individual variation in autumn and winter body mass of moose calves living at low density on an island in northern Norway to characteristics of their mother, and examine how these relationships are affected by annual variation in population density and climate. Body mass increased with increasing age of their mother, was lower for calves born late in the spring, decreased with litter size and was larger for males than for female calves. No residual effects of variation in density and climate were present after controlling for annual variation in mother age and calving date. The annual variation in adult female age structure and calving date explained a large part (71–75%) of the temporal variation in calf body mass. These results support the hypotheses that (a) body mass of moose calves are affected by qualities associated with mother age (e.g. body condition, calving date); and (b) populations living at low densities are partly buffered against temporal fluctuations in the environment.     

Population genetic models can be used to study the evolution of the interacting behaviours of parents and their progeny

An example of the evolution of the interacting behaviours of parents and progeny is studied using iterative equations linking the frequencies of the gametes produced by the progeny to the frequencies of the gametes in the parental generation. This population genetics approach shows that a model in which both behaviours are determined by a single locus can lead to a stable equilibrium in which the two behaviours continue to segregate. A model in which the behaviours are determined by genes at two separate loci leads eventually to fixation of the alleles at both loci but this can take many generations of selection. Models of the type described in this paper will be needed to understand the evolution of complex behaviour when genomic or experimental information is available about the genetic determinants of behaviour and the selective values of different genomes.     

Maternal effects on phase characteristics in the desert locust, Schistocerca gregaria: a review of current understanding

Desert locusts demonstrate pronounced density-dependent polyphenism: a complex suite of traits shifts over the lifetime of an individual in response to crowding or isolation. These changes also accumulate across generations through a maternal effect. Female desert locusts alter the developmental trajectory of their offspring in response to their own experience of crowding. The mother possesses a memory of both the recency and extent of crowding and shifts the phase state of her hatchlings accordingly. Extensive experimental work has shown that offspring behaviour is controlled by a low molecular weight, polar compound (or compounds) released from the mother's accessory glands. The chemical identity of this agent is not yet known.     

Identification of a B-cell epitope of hyaluronidase, a major bee venom allergen, from its crystal structure in complex with a specific Fab

The major allergens of honeybee venom, hyaluronidase (Hyal) and phospholipase A2, can induce life-threatening IgE-mediated allergic reactions in humans. Although conventional immunotherapy is effective, up to 40% of patients develop allergic side effects including anaphylaxis and thus, there is a need for an improved immunotherapy. A murine monoclonal anti-Hyal IgG1 antibody (mAb 21E11), that competed for Hyal binding with IgEs from sera of bee venom allergic patients, was raised. The fragment of these IgG antibodies which bind to antigen (Fab) was produced and complexed (1:1) with Hyal. The crystal structure determination of Hyal/Fab 21E11 complex (2.6 A) enabled the identification of the Hyal-IgG interface which provides indirect information on the Hyal-IgE interaction (B-cell epitope). The epitope is composed of a linear array of nine residues (Arg138, His141-Arg148) located at the tip of a helix-turn-helix motive which protrudes away from the globular core and fits tightly into the deep surface pocket formed by the residues from the six complementarity determining regions (CDRs) of the Fab. The epitope is continuous and yet its conformation appears to be essential for Ab recognition, since the synthetic 15-mer peptide comprising the entire epitope (Arg138-Glu152) is neither recognized by mAb 21E11 nor by human IgEs. The structure of the complex provides the basis for the rational design of Hyal derivatives with reduced allergenic activity, which could be used in the development of safer allergen-specific immunotherapy.     

Maternal behavior in pigs

When sows kept under commercial conditions were put into crates in the early 1960s, the neuro-endocrine regulation of the maternal behavior in these domestic animals was disputed. Thus, the study of sow maternal behavior intensified and today a significant body of knowledge has accumulated to support the hormonal regulation of sow maternal behavior. The onset of nest building is associated with a periparturient decline in progesterone, an increase in prolactin and a major rise in plasma concentrations of PGF2alpha the day before parturition. Some nest building behaviors, such as pawing and gathering straw, have been found to correlate with changes in the levels of progesterone, prolactin and somatostatin. The duration of the birth process correlates negatively with peripheral oxytocin levels. During lactation, the stimuli from the piglets affect the release of several hormones which not only regulate the let down of milk but also sow metabolism and mammary milk production. The sow's nursing behavior ensures an even distribution of milk to her piglets. The piglets suckling behavior, in turn, is mainly a way to communicate their individual nutritional needs.     

Maternal behavior in cattle

We provide a critical summary of the literature on maternal behavior in cattle. The studies we review increase our basic understanding of this behavior and provide insights into practical problems in cattle production. When domesticated cattle are permitted to rear their young, the behaviors associated with maternal care are for the most part similar to those observed in wild ungulates. These behaviors allow the cow to bond with her calf, protect and provide it with nourishment and ultimately break down this bond at weaning. Different commercial production systems have emphasized different maternal behaviors, some being viewed as advantageous while others are considered a hindrance. Extensive production systems (most beef cattle production) place the responsibility of rearing the newborn largely on the cow and risk factors that affect the maternal bonding process (e.g. cross licking) remain important practical challenges. Most dairy cattle production discourages all aspects of maternal behavior with the exception of milk production, but changing consumer demand (e.g. increases in organic production) will make an understanding of maternal behavior in this system a priority in years to come.     

Indo-Fijian Children’s BMI

Health research has shown that overweight and obesity in children and adults are becoming significant public health problems in the developing world. Evidence suggests that this phenomenon is more marked in urban than rural areas and may be associated with modernization. However, the underlying reasons for this nutrition transition remain unclear. Dietary shifts, often in conjunction with income and time constraints in urban environments, may entail a greater reliance on more convenient sugar and fat-dense food. Also, the necessity of labor-intensive agricultural work to meet rural subsistence needs is supplanted in urban environments by sedentary work. This paper extends the application of human behavioral ecology theory into the realm of international development and policy by applying Kaplan’s embodied capital theory to explore differences in food habits and nutritional status of Indo-Fijian children within the context of urbanization. Urban high-embodied-capital women demonstrate higher rates of wage-earning employment than urban low-embodied-capital or rural women. Findings indicate that urban high-embodied-capital households spend significantly more on food purchases, purchase a greater proportion of processed foods, and have children with higher body mass indexes (BMI) than do urban low-embodied-capital or rural households. This suggests that urban high-embodied-capital mothers, who tend to be employed, may be making trade-offs between income and food choices.

van der Waals forces influencing adhesion of cells

Adhesion molecules, often thought to be acting by a ‘lock and key’ mechanism, have been thought to control the adhesion of cells. While there is no doubt that a coating of adhesion molecules such as fibronectin on a surface affects cell adhesion, this paper aims to show that such surface contamination is only one factor in the equation. Starting from the baseline idea that van der Waals force is a ubiquitous attraction between all molecules, and thereby must contribute to cell adhesion, it is clear that effects from geometry, elasticity and surface molecules must all add on to the basic cell attractive force. These effects of geometry, elasticity and surface molecules are analysed. The adhesion force measured between macroscopic polymer spheres was found to be strongest when the surfaces were absolutely smooth and clean, with no projecting protruberances. Values of the measured surface energy were then about 35 mJ m⁻², as expected for van der Waals attractions between the non-polar molecules. Surface projections such as abrasion roughness or dust reduced the molecular adhesion substantially. Water cut the measured surface energy to 3.4 mJ m⁻². Surface active molecules lowered the adhesion still further to less than 0.3 mJ m⁻². These observations do not support the lock and key concept.