Variation of natural reproduction parameters and Crow’s indices in different ethnic groups in the two largest megacities of Russia

Genetic-demographic parameters of natural reproduction in the most numerous ethnic groups of Moscow and St. Petersburg were assessed on the basis of the 2002 All-Russia Population Census data and other sources. The intensity of intragroup selection due to individual differences in fertility in the cohorts of women born in the 1930s–1950s decreased in all ethnic groups studied. It was concluded that, in both megacities, the relaxation of the selection component due to differential fertility almost stopped: the values of the Crow’s index I_f stabilized at 0.3 < I_f < 0.4, which was associated with relative stabilization of the interfamily variance of fertility. The temporal dynamics of the intensity of intergroup selection due to interethnic differences in fertility rates was more complex. It was only recently that this type of selection came into action, since even at the beginning of the 20th century fertility rates in various ethno-territorial and ethno-confessional groups of the population of the Russian Empire were similar (5–6 offspring per marriage). In the subsequent decades, interethnic differentiation in progeny size increased because the reproductive behavior of different population groups underwent “modernization” with uneven speed. In Moscow and St. Petersburg, the intensity of intergroup selection decreased in women birth cohorts of the 1930s–1950s, while it was an order of magnitude lower than the intragroup selection. Currently, the average number of offspring varies among ethnic groups in a narrow range from 1.3 to 1.6. It can be expected that interethnic differences in fertility rates in these megacities will increase again owing to growing numbers of migrants from regions with traditionally high birth rates, resulting in differential natural growth of ethnic groups and the corresponding dynamics of the gene pool of the population.     

Adaptive changes in the concentration of the mitochondrial ‘uncoupling’ protein in brown adipose tissue of hamsters acclimated at different temperatures

The effect of acclimation at different temperatures on the activity of interscapular brown adipose tissue has been investigated in the hamster, a hibernator. Between 31° and 4°C the cytochrome oxidase activity of the tissue increased 4- to 5-fold, mitochondrial GDP binding per mg of mitochondrial protein doubled, and the amount of uncoupling protein rose from 1.7% to 5.4% of total mitochondrial protein. It is concluded that there are clear adaptive changes induced by temperature in brown adipose tissue of the hamster, but the changes are limited in comparison with those in the mouse.     

Variation of the parameters of natural reproduction and Crow’s indices in the ethnic groups of Dagestan

Using the 2002 All-Russian population census data, the parameters of differential fertility as a component of natural selection (Crow??s indices) have been calculated for women of seven age cohorts of the seven most numerous ethnic groups of the Republic of Dagestan. It has been shown that in the population of Dagestan in the second half of the 20th century the intensities of two types of selection tended to decrease, viz., intragroup selection relaxed in each ethnic group due to considerable reduction of interfamily variance in fertility and intergroup selection relaxed due to reduction of interethnic differences in fertility. A reduction of the average number of offspring (k) was observed in all ethnic groups, suggesting the spread of birth regulation practices (abortion and contraception). Nevertheless, all Muslim groups (aboriginal Dagestan ethnic groups and Azerbaijanis) are still characterized by an extended pattern of reproduction (2.7 < k < 3.3); in Russians k = 2.1. Interethnic differentials in natural reproduction rates, along with migration processes, account for the dynamics of the ethnic composition and gene-pool structure of the population of the Republic of Dagestan.     

Cumulative indices of DNA synthesizing myocytes in different compartments of the working myocardium and conductive system of the rat’s heart muscle following extensive left ventricle infarction

Ten successive³H-thymidine injections at 12h intervals (which is a little shorter than the adult heart myocyte S phase) were performed for labeling of the majority of cardiac myocytes synthesizing DNA at any moment of such a 5 days experiment. In the hearts of control unoperated rats ten-fold repeated³H-thymidine administration results in labeling of 2–3% myocyte nuclei, in both atria, ca. 1% of the specialized muscle cell nuclei in the atrioventricular conductive system, only occasional muscle cells being labeled in the working ventricular myocardium. When ten successive³H-thymidine injections were made between the 5th and 10th days following extended left ventricle infarction, the percentage of labeled myocytes in left and right atria reaches, respectively, 51.4±4.4% and 34.7±3.6%. In the left ventricle labeled muscle nuclei are accumulated predominantly (9.3±2.1%) within the thin subepicardial layer of the surviving myofibers, while myofibers located in other perinecrotic areas contained only 1.3±0.5% labeled muscle nuclei. The number of these nuclei in the atrioventricular system remains at the level observed in control hearts (up to 2%), approaching closely the zero level in the working myocardium of both the ventricles and interventricular septum, located at the considerable distance from the infarcted region. When similar experiments with ten-fold repeated³H-thymidine injections were performed between 15th and 20th post-infarction days the number of labeled myocyte nuclei was found to be reduced 4–6 times in atria, being changed rather a little in the perinecrotic ventricular myocardium and in the specialized myocardium of the atrioventricular system. Some possible reasons of the observed differences in the proliferative behaviour of cardiac myocytes in terms of their topology and/or specialization are discussed     

Should ecological factors affect the evolution of age at maturity in freshwater clams?

We studied the evolution of age at maturity in freshwater clams of the genus Anodonta in relation to their ecology. We analysed an age-structured density-dependent population dynamics model, which we developed for freshwater clams, using several different options for density dependence. As evolutionary optimality criteria we applied both the maximization of a fitness measure (either intrinsic rate of increase or expected lifetime fecundity) and the concept of evolutionarily stable strategies (ESSs). All three evolutionary criteria yielded estimates which were too high for the optimal age at maturity in a deterministic model with a constant survival rate. The predictions are improved when size-selective predation is included in the model. Mature clams also face a risk of infection by castrating parasites, which would select for delayed maturity. Variable newborn survival selects for earlier reproduction, though the observed levels of stochasticity probably have a negligible effect.     

Paradigm shift in treatment of coarctation of the aorta?

Netherlands Heart Journal -     

Estimation of genetic parameters for longevity considering the cow’s age at last calving

The aim of this study was to estimate heritability and predict breeding values for longevity among cows in herds of Nellore breed, considering the trait cow’s age at last calving (ALC), by means of survival analysis methodology. The records of 11,791 animals from 22 farms were used. The variable ALC has been used by a criterion that made it possible to include cows not only at their first calving but also at their ninth calving. The criterion used was the difference between the date of each cow’s last calving and the date of the last calving on each farm. If this difference was greater than 36 months, the cow was considered to have failed and uncensored. If not, this cow was censored, thus indicating that future calving remained possible for this cow. The survival model used for the analyses was the proportional hazards model, and the base risk was given by a Weibull distribution. The heritability estimate obtained was equal to 0.25. It was found that the ALC variable had the capacity to respond to selection for the purpose of increasing the longevity of the cows in the herds.     

Does age affect the relationship between control at work and sleep disturbance for shift workers?

Among miners, shift work, aging and lack of control at work may be factors leading to increased sleep problems. Such risk factors may also operate in interaction, resulting in an even increased harm for sleep disruption. The present study aims at evaluating these relationships drawing on a sample of Australian mine and energy workers and their partners. The workers were mainly men. All performed shift work that included either nights (95%) or multiple shifts (92%), usually both (87%), while 36% were aged 50 years or above. The results show that low latitude over work activities is associated with higher sleep disturbances across the sample, though the effects are clearer amongst younger workers. By contrast, for younger workers, control over shift scheduling is not associated with sleep disturbances but for workers aged 50 or more, low control results in more sleep disturbance. Misalignment between shift workers and partner work schedules, and partner dissatisfaction with shift worker's employment and shift worker's work-life balance, are also associated with more sleep disturbances amongst shift workers.     

Growth,reproduction, and age at maturity of Lessa’s butterfly ray Gymnura lessae in the northern Gulf of Mexico

Environmental Biology of Fishes - In the northern Gulf of Mexico, batoids are caught as bycatch in the shrimp trawl fishery and targeted by recreational bowfishers. The vulnerability of these...     

The Specificity of Controlled Protein Disorder in the Photoprotection of?Plants

Light-harvesting pigment-protein complexes of photosystem II of plants have a dual function: they efficiently use absorbed energy for photosynthesis at limiting sunlight intensity and dissipate the excess energy at saturating intensity for photoprotection. Recent single-molecule spectroscopy studies on the trimeric LHCII complex showed that environmental control of the intrinsic protein disorder could in principle explain the switch between their light-harvesting and photoprotective conformations in vivo. However, the validity of this proposal depends strongly on the specificity of the protein dynamics. Here, a similar study has been performed on the minor monomeric antenna complexes of photosystem II (CP29, CP26, and CP24). Despite their high structural homology, similar pigment content and organization compared to LHCII trimers, the environmental response of these proteins was found to be rather distinct. A much larger proportion of the minor antenna complexes were present in permanently weakly fluorescent states under most conditions used; however, unlike LHCII trimers the distribution of the single-molecule population between the strongly and weakly fluorescent states showed no significant sensitivity to low pH, zeaxanthin, or low detergent conditions. The results support a unique role for LHCII trimers in the regulation of light harvesting by controlled fluorescence blinking and suggest that any contribution of the minor antenna complexes to photoprotection would probably involve a distinct mechanism.     

Assessment of intersegmental coordination of rats during walking at different speeds – Application of continuous relative phase

The present study investigated the feasibility and reliability of continuous relative phase (CRP) and deviation phase (DP) to assess intersegmental hind limb coordination pattern and coordination variability in rats during walking. Twenty-six adult rats walked at 8 m/min, 12 m/min and 16 m/min while two-dimensional kinematics were recorded. Segment angles and segment angular velocities of the paw, shank and thigh on the left hind-limb were extracted from 15 strides and CRP was calculated for the paw-shank and shank-thigh coupling. The effect of walking speed on the time point average curve of the CRP (ACRP) and DP and on the mean ACRP and mean DP was established by statistical parametric mapping (SPM) and a one-way ANOVA for repeated measures. Absolute and relative reliability were assessed by measurement error and intra-class correlation coefficient. The SPM analysis revealed time dependent differences in the effect of speed. Thus, the CRP of the paw-shank coupling decreased with increasing speed during most of the gait cycle while the CRP of the shank-thigh coupling was decreased during the swing phase. The session-to-session reliability was fair to good for the coordination measure and poor for the variability measure.     

Huntington’s disease: the coming of age

Huntington’s disease (HD) is caused due to an abnormal expansion of polyglutamine repeats in the first exon of huntingtin gene. The mutation in huntingtin causes abnormalities in the functioning of protein, leading to deleterious effects ultimately to the demise of specific neuronal cells. The disease is inherited in an autosomal dominant manner and leads to a plethora of neuropsychiatric behaviour and neuronal cell death mainly in striatal and cortical regions of the brain, eventually leading to death of the individual. The discovery of the mutant gene led to a surge in molecular diagnostics of the disease and in making different transgenic models in different organisms to understand the function of wild-type and mutant proteins. Despite difficult challenges, there has been a significant increase in understanding the functioning of the protein in normal and other gain-of-function interactions in mutant form. However, there have been no significant improvements in treatments of the patients suffering from this ailment and most of the treatment is still symptomatic. HD warrants more attention towards better understanding and treatment as more advancement in molecular diagnostics and therapeutic interventions are available. Several different transgenic models are available in different organisms, ranging from fruit flies to primate monkeys, for studies on understanding the pathogenicity of the mutant gene. It is the right time to assess the advancement in the field and try new strategies for neuroprotection using key pathways as target. The present review highlights the key ingredients of pathology in the HD and discusses important studies for drug trials and future goals for therapeutic interventions.     

Inverse agonism at α2A adrenoceptors augments the hypophagic effect of sibutramine in rats

Because the use of monoamine reuptake inhibitors as weight-reducing agents is limited by adverse effects, novel antiobesity drugs are needed. We studied acute effects of the noradrenaline (NA) and serotonin (5-HT) reuptake inhibitor sibutramine (SIB), alone and after pretreatment with α1- and α2-adrenoceptor (AR), and 5-HT1/2/7, 5-HT1B and 5-HT2C receptor antagonists in order to determine which ARs and 5-HT receptors act downstream of SIB on feeding and locomotion. Acute effects on caloric and water intake, meal microstructure and locomotion were assessed, using an automated weighing system and telemetry in male rats with restricted 18-h access to Western style diet. SIB 3 mg/kg reduced meal size and frequency, which suggests enhanced within- and postmeal satiety. Imiloxan (α2B-AR), WB4101 (α1-AR), SB-224289 (5-HT1B), and modestly BRL 44408 (α2A/D-AR) attenuated SIB's effect on meal size, suggesting that α2B- and α1-ARs and 5-HT1B receptors mediate within-meal satiety, with a modest role for α2A/D-ARs. Only prazosin (α1/2B/2C-AR) counteracted SIB's effect on meal frequency. At 3 mg/kg, SIB modestly increased locomotion. This effect was blocked by metergoline (5-HT1/2/7), WB4101 (α1-AR), and RX821002 (α2-AR). Interestingly, the α2-AR antagonists atipamezole and RX821002 enhanced SIB's effect on caloric intake, probably due to inverse agonistic actions at α2A-autoreceptors that further enhanced release of NA that regulates caloric intake. Thus, an inverse agonist of presynaptic α2A-ARs might beneficially enhance SIB's weight-reducing effect and offer novel treatment for obesity. All in all, the present data supports the ARs and 5-HT receptors involved in the effects of SIB on different aspects of caloric intake and locomotion.     

The renoprotective effects of berberine via the EP4-Gαs-cAMP signaling pathway in different stages of diabetes in rats

Abstract

Aims: To investigate the renoprotective roles of berberine (BBR) in different stages of diabetic nephropathy (DN) in streptozotocin (STZ)-induced diabetic rats fed a high-sugar and high-fat diet. Methods: Diabetes was induced in mice by intraperitoneal injection of STZ, and the mice were then randomly divided into groups: normal, diabetes, high-sugar and high-fat and BBR (high, median and low dose) groups. The body weight (BW), kidney weight to body weight (KW/BW), blood urea nitrogen, urine total protein to urine creatinine ratio and serum creatinine were measured on different weeks throughout the study. The protein levels of E prostanoid receptor 4 (EP4), Gαs and content of cAMP in the kidney were, respectively, detected by western blot analysis and RIA analysis. Results: In the DN rats, there was remarkable renal damage. BBR restored renal functional parameters, suppressed alterations in histological and ultrastructural changes in the kidney tissues and increased EP4, Gαs and cAMP levels compared with those of the DN model group. In addition, BBR has different therapeutic effects during the different stages of the development of DN, and it works best in the sixth week. Conclusion: These studies demonstrate, for the first time, that BBR exerts renoprotective effects in different stages of DN via EP4- Gαs- AC-cAMP signaling pathway in STZ-induced DN rats fed a high-sugar and high-fat diet.     

Does the age of fine root carbon indicate the age of fine roots in boreal forests?

To test the reliability of the radiocarbon method for determining root age, we analyzed fine roots (originating from the years 1985?C1993) from ingrowth cores with known maximum root age (1?C6?years old). For this purpose, three Scots pine (Pinus sylvestris L.) stands were selected from boreal forests in Finland. We analyzed root ¹⁴C age by the radiocarbon method and compared it with the above-mentioned known maximum fine root age. In general, ages determined by the two methods (root ¹⁴C age and ingrowth core root maximum age) were in agreement with each other for roots of small diameter (<0.5?mm). By contrast, in most of the samples of fine roots of larger diameter (1.5?C2?mm), the ¹⁴C age of root samples of 1987?C1989 exceeded the ingrowth core root maximum age by 1?C10?years. This shows that these roots had received a large amount of older stored carbon from unknown sources in addition to atmospheric CO₂ directly from photosynthesis. We conclude that the ¹⁴C signature of fine roots, especially those of larger diameter, may not always be indicative of root age, and that further studies are needed concerning the extent of possible root uptake of older carbon and its residence time in roots.