Intergenerational transmission of insulin resistance and type 2 diabetes

Studies in women with type 1 or type 2 diabetes mellitus (DM) and their children suggest that the in utero ‘diabetic’ environment in which the fetus develops can increase the risk of diabetes in the child, in a non-genetic but heritable fashion. Studies in rodents provide strong evidence for maternal transmission of diabetes, but are based primarily on a model type 1 DM and there is no standard animal model of type 2 DM in pregnancy or of gestational diabetes mellitus (GDM), although those reported uniformly show glucose intolerance in the offspring. Rodent models of diet-induced obesity have relevance to current upward trends in maternal obesity and GDM, although maternal glucose homeostasis is not always assessed and elements of the diet may have an independent influence. The mechanisms by which maternal type 2DM evokes a higher risk of the disorder in the offspring are likely to result from epigenetic modification in early life of pathways of pancreatic β cells and of liver and muscle insulin signalling pathways. Also, epigenetic processes associated with hormonal imbalance may lead to irreversible ‘reordering’ of hypothalamic neural networks in fetal/neonatal life, permanently alter energy balance and lead to obesity with associated insulin resistance.     

Impact of Phyllostachys heterocycla ‘Pubescens’ expansion on mycorrhizal associations of the adjacent forests

 毛竹(Phyllostachys heterocycla ‘Pubescens’)凭借其独特的生长特性极易扩张进入周边的常绿或针阔混交森林群落并取而代之。菌根减弱假说对毛竹林扩张导致周边林分枯亡并抑制林下幼苗更新的机制进行了解释, 即毛竹林的成功扩张是由于毛竹蔓延引起森林群落的菌根系统紊乱, 使宿主植物与菌根真菌的共生关系受到干扰, 进而影响了宿主植物的分布与更新。该研究以浙江省西天目山国家自然保护区为研究区域, 对菌根减弱假说进行了检验。通过在毛竹-针阔混交林交接区沿毛竹扩张方向设置毛竹纯林、竹-林过渡带、针阔混交林3种类型的样带, 选取在针阔混交林、竹-林过渡带同时存在的6种优势乔灌树种——杉木(Cunninghamia lanceolata)、枫香树(Liquidambar formosana)、青冈(Cyclobalanopsis glauca)、柳杉(Cryptomeria fortunei)、江浙山胡椒(Lindera chienii)、毛柄连蕊茶(Camellia fraterna), 测定这6个树种在两样带中的菌根侵染频率和强度, 检测在毛竹林扩张中周边森林群落菌根的响应, 同时对比了毛竹在毛竹纯林和竹-林过渡带菌根感染率和强度的变化, 检验该假设。实验结果表明: 1)针阔混交林和竹-林过渡带的主要树种菌根都具有较高的菌根侵染频率(> 95%), 且不同林分间林木的侵染频率无显著差异(p > 0.1); 2)在竹-林过渡带杉木和江浙山胡椒的丛枝菌根侵染强度较针阔混交林明显增加(p < 0.1); 3)毛竹的丛枝菌根侵染频率和强度远低于其他针阔树种, 且在扩张前后没有显著变化(p > 0.1)。实验结果否定菌根减弱假说。     

Agility and search and rescue training differently affects pet dogs’ behaviour in socio-cognitive tasks

Both genetic factors and life experiences appear to be important in shaping dogs’ responses in a test situation. One potentially highly relevant life experience may be the dog's training history, however few studies have investigated this aspect so far. This paper briefly reviews studies focusing on the effects of training on dogs’ performance in cognitive tasks, and presents new, preliminary evidence on trained and untrained pet dogs’ performance in an ‘unsolvable task’. Thirty-nine adult dogs: 13 trained for search and rescue activities (S&R group), 13 for agility competition (Agility group) and 13 untrained pets (Pet group) were tested. Three ‘solvable’ trials in which dogs could obtain the food by manipulating a plastic container were followed by an ‘unsolvable’ trial in which obtaining the food became impossible. The dogs’ behaviours towards the apparatus and the people present (owner and researcher) were analysed. Both in the first ‘solvable’ and in the ‘unsolvable’ trial the groups were comparable on actions towards the apparatus, however differences emerged in their human-directed gazing behaviour. In fact, results in the ‘solvable’ trial, showed fewer S&R dogs looking back at a person compared to agility dogs, and the latter alternating their gaze between person and apparatus more frequently than pet dogs. In the unsolvable trial no difference between groups emerged in the latency to look at the person however agility dogs looked longer at the owner than both pet and S&R dogs; whereas S&R dogs exhibited significantly more barking (always occurring concurrently to looking at the person or the apparatus) than both other groups. Furthermore, S&R dogs alternated their gaze between person and apparatus more than untrained pet dogs, with agility dogs falling in between these two groups. Thus overall, it seems that the dogs’ human-directed communicative behaviours are significantly influenced by their individual training experiences.     

The Relationship of Sugar to Population-Level Diabetes Prevalence: An Econometric Analysis of Repeated Cross-Sectional Data

While experimental and observational studies suggest that sugar intake is associated with the development of type 2 diabetes, independent of its role in obesity, it is unclear whether alterations in sugar intake can account for differences in diabetes prevalence among overall populations. Using econometric models of repeated cross-sectional data on diabetes and nutritional components of food from 175 countries, we found that every 150 kcal/person/day increase in sugar availability (about one can of soda/day) was associated with increased diabetes prevalence by 1.1% (p <0.001) after testing for potential selection biases and controlling for other food types (including fibers, meats, fruits, oils, cereals), total calories, overweight and obesity, period-effects, and several socioeconomic variables such as aging, urbanization and income. No other food types yielded significant individual associations with diabetes prevalence after controlling for obesity and other confounders. The impact of sugar on diabetes was independent of sedentary behavior and alcohol use, and the effect was modified but not confounded by obesity or overweight. Duration and degree of sugar exposure correlated significantly with diabetes prevalence in a dose-dependent manner, while declines in sugar exposure correlated with significant subsequent declines in diabetes rates independently of other socioeconomic, dietary and obesity prevalence changes. Differences in sugar availability statistically explain variations in diabetes prevalence rates at a population level that are not explained by physical activity, overweight or obesity.     

VDR TaqI is associated with obesity in the Greek population

The prevalence of obesity has increased dramatically during the last thirty years in western countries with severe complications for health and economy. Obesity is the outcome of the strong interplay between genetic and environmental factors and is therefore widely expected that the discovery of the many genetic factors underlying the heritable risk of obesity will contribute critically to our basic knowledge of the disease etiopathogenesis and the identification of new targets for therapeutic intervention. The aim of the present study was to assess the genetic contribution of known polymorphisms in two genes that are linked to the pathogenetic mechanism of obesity. Analysis of vitamin D receptor (VDR) TaqI (rs731236; T/C) and fat mass and obesity-associated (FTO) (rs9930506; A/T) polymorphisms in 82 obesity subjects and 102 controls showed significant association for VDR TaqI ‘T’ allele and obesity (OR: 2.07; 1.123–3.816; P = 0.019), contributing to an elevated BMI of 3 kg/m² per risk allele. No association was observed for the FTO polymorphism. These results further support a role for VDR as risk factor for obesity and suggest its further validation in larger independent populations as well as highlight a target for functional analysis towards therapeutic intervention in obese individuals.     

Change in Obesity Prevalence across the United States Is Influenced by Recreational and Healthcare Contexts,Food Environments,and Hispanic Populations

Objective

To examine change in county-level adult obesity prevalence between 2004 and 2009 and identify associated community characteristics.

Methods

Change in county-level adult (≥20 years) obesity prevalence was calculated for a 5-year period (2004–2009). Community measures of economic, healthcare, recreational, food environment, population structure, and education contexts were also calculated. Regression analysis was used to assess community characteristics associated (p<0.01) with change in adult obesity prevalence.

Results

Mean±SD change in obesity prevalence was 5.1±2.4%. Obesity prevalence decreased in 1.4% (n = 44) and increased in 98% (n = 3,060) of counties from 2004–2009. Results showed that both baseline levels and increases in physically inactive adults were associated with greater increases in obesity prevalence, while baseline levels of and increases in physician density and grocery store/supercenter density were related to smaller increases in obesity rates. Baseline levels of the Hispanic population share were negatively linked to changing obesity levels, while places with greater Hispanic population growth saw greater increases in obesity.

Conclusions

Most counties in the U.S. experienced increases in adult obesity prevalence from 2004 to 2009. Findings suggest that community-based interventions targeting adult obesity need to incorporate a range of community factors, such as levels of physical inactivity, access to physicians, availability of food outlets, and ethnic/racial population composition.     

Obesity, attention deficit-hyperactivity disorder and the dopaminergic reward system

The obesity epidemic has focused attention on obesity's health consequences beyond cardio-vascular disease and diabetes. To evaluate the potential consequences of obesity for Attention Deficit-Hyperactivity Disorder (ADHD), we surveyed the literature. Current findings link both obesity and ADHD to the dopamine system and implicate dopamine genes in body weight, eating, and ADHD. Detailed consideration suggests that dopaminergic changes in the prefrontal cortex among individuals with the ADHD subtype Attention Deficit Disorder (ADD) may increase their risk for obesity. Thus, individuals and populations with a high prevalence of hyperdopaminergic genes may experience higher rates of obesity in the presence of abundant food. From an evolutionary perspective, alterations in the dopamine system appear to effect a wide range of behavioral phenotypes. We suggest that recent evolutionary changes in the dopamine receptor genes selected to increase cognitive and behavioral flexibility may now be associated with attention problems and increased food consumption in an obesogenic environment.     

Culture and the evolution of obesity

Human predispositions to fatness and obesity are best understood in the context of cultural and biological evolution. Both genes and cultural traits that were adaptive in the context of past food scarcities play a role today in the etiology of maladaptive adult obesity. The etiology of obesity must account for the social distribution of the condition with regard to gender, ethnicity, social class, and economic modernization. This distribution, which has changed throughout history, undoubtedly involves cultural factors. A model of culture is presented that has advantages over an undifferentiated concept of the “environment” for hypothesis generation. Cultural predispositions to obesity are found in the productive economy, the mode of reproduction, social structure, and cultural beliefs about food and ideal body size. Cross-cultural comparison can contribute to an understanding of the prevalence of obesity in some modern affluent societies.     

Obestatin, obesity and diabetes

The high prevalence of obesity and diabetes will lead to higher rates of morbidity and mortality. It is well known that ghrelin plays a potential role in obesity and diabetes. Obestatin, a novel 23 amino acid amidated peptide encoded by the same gene that encodes ghrelin, was initially reported to have opposite actions to ghrelin in the regulation of food intake, emptying of the stomach and body weight. Recent work suggests that obestatin also regulate beta-cell survival and insulin secretion. The ghrelin-obestatin system is, therefore, a promising target for the developing of new drugs for the treatment of obesity and diabetes. This review summarizes the interrelationship between obestatin, obesity and diabetes.     

Muscle proteins — their actions and interactions

Muscle contracts by the myosin cross-bridges ‘rowing’ the actin filaments past the myosin filaments. In the past year many structural details of this mechanism have become clear. Structural studies indicate distinct states for myosin S1 in the rigor, ATP or ‘down’ conformation and in the products complex (ADP·P_i) or ‘up’ state. Crystallographic studies substantiate this classification and yield details of the transformation. The isomerization ‘up’ to ‘down’ is the power stroke of muscle. This consists in the main of large changes of angle of the ‘lever arm’ (at the distal part of the myosin head) which can account for an 11 nm power stroke.     

The effects of enhancing cage complexity on the behaviour and welfare of laboratory rats

This experiment was carried out to investigate the long-term effects of enhancing cage complexity on behavioural measures of welfare in laboratory rats. We housed 72 rats in groups of four in either ‘enriched’ or ‘unenriched’ cages for six weeks. Scan and focal animal sampling were conducted in both the light and dark phase of the second, fourth and sixth weeks. Results revealed that rats in the ‘enriched’ cages showed longer durations of sleep behaviour, and low levels of agonistic behaviour compared to rats in the ‘unenriched’ cages. Results importantly demonstrated that the behavioural changes observed in the enriched environment were due to the presence of the enrichments themselves in the cages (indirect effects) and not due merely to rats interacting with the enrichment items in their environment. Thus, enhancing the complexity of conventional laboratory cages can promote behaviour such as longer bouts of sleep that is likely to be indicative of good welfare, and diminish levels of behaviour such as aggression that is likely to lead to poor welfare.     

Species, clusters and the ‘Tree of life’: A graph-theoretic perspective

A hierarchical structure describing the inter-relationships of species has long been a fundamental concept in systematic biology, from Linnean classification through to the more recent quest for a ‘Tree of Life’. In this paper we use an approach based on discrete mathematics to address a basic question: could one delineate this hierarchical structure in nature purely by reference to the ‘genealogy’ of present-day individuals, which describes how they are related with one another by ancestry through a continuous line of descent? We describe several mathematically precise ways by which one can naturally define collections of subsets of present day individuals so that these subsets are nested (and so form a tree) based purely on the directed graph that describes the ancestry of these individuals. We also explore the relationship between these and related clustering constructions.     

Rise rate and timing variability of surface electromyographic activity during rhythmic drumming movements in the world’s fastest drummer

The winner of an international contest to find the world’s fastest drummer (WFD) can perform repetitive wrist tapping movements with one hand using a handheld drumstick at 10 Hz, much faster than the maximum tapping frequency of 5-7 Hz in the general population. The muscle activity facilitating this improved performance, however, has only recently been explored. The present study investigated the rise rate and timing variability of surface electromyographic (EMG) activity of wrist flexor/extensor muscles in the WFD, and compared them with those in two control groups: non-drummers (NDs) and ordinary drummers (ODs). The WFD showed more rapid EMG amplitude rise, earlier decline of EMG activity, and more stable muscle activation time than the NDs and ODs. In addition, there was a significant correlation between the EMG rise rate and the duration of drum training in the group of drummers (i.e., ODs and WFD). These results indicate that the 10-Hz performance of the WFD was achieved by a ‘sharper’ and ‘less noisy’ burst pattern of wrist muscles, and that drum training would have the effect to increase the speed of development of muscle tension.     

The effect of female presence on spermiation, and of male sexual activity on ‘ready’ sperm in the male guppy

This study examines the effect of female presence on the amount of ‘strippable’ sperm, and the relationship between male sexual activity and the amount of ‘ready’ sperm in the male guppy Poecilia reticulata. The amount of strippable sperm was greater in males paired for one week with females than in isolated males. We separated these ‘paired’ males from females by a clear partition and thus exposed males to visual and possibly olfactory stimuli. In the second experiment, control males spent more time attending females and performed more sexual acts during a 15-min test period than males previously stripped of spermatophores. These results indicate that females play an important role in stimulating sperm availability in males and that the amount of ready sperm influences male sexual behaviour. Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.      

Reversible vesicles based on one and two head supramolecular cyclodextrin amphiphile induced by methanol

Reversible vesicles based on supramolecular inclusion of hydroxypropyl-β-CD (HPβCD) and N,N′-bis(ferrocenylmethylene)-diaminohexane (BFD) were prepared in water and methanol-water mixtures. The inclusion stoichiometry of HPβCD with BFD was in a molar ratio of 2:1, which could be named as ‘two head’ supramolecular amphiphile when the solvent was water. However, the inclusion stoichiometry of HPβCD with BFD would tend to be a molar ratio of 1:1 based on introduction of methanol to the solvent, especially when the volume ratio of methanol and water was more than 1:4, which could be named as ‘one head’ supramolecular amphiphile. The inclusion compounds could switch between ‘one head’ and ‘two head’ conformations by changing the methanol concentration of the solvents. The vesicles were also found to be responsive to the stimulus of external molecules. When the inclusion ability between HPβCD and an external guest was relatively stronger, the vesicles were easily destroyed. Furthermore, the vesicles disappeared after adding an oxidizing agent. NMR was used to confirm the conformation of the mixture of HPβCD and BFD in water. The structure and morphology of the vesicles were characterized by TEM and DLS. The vesicles may be used in smart materials, drug delivery and molecular recognition.     

Seasonal variations in the energy budget of Elliot’s pheasant (Syrmaticus ellioti) in cage

This study aimed to discuss the energy budget of Elliot’s pheasant Syrmaticus ellioti in different seasons, with life and health, good growth and normal digestion of Elliot’s pheasant as the tested objects, The energy budget of Elliot’s pheasant was measured by daily collection of the trial pheasants’ excrement in the biological garden of Guangxi Normal University from March 2011 to February 2012. The results showed that the gross energy consumption, metabolic energy and excrement energy varied by season, increasing as temperature decreased. There was significant difference in gross energy consumption, metabolic energy, excrement energy between adults and nonages. There was also a trend that food digestibility of pheasants increases as temperature increases. In the same season, the food digestibility of adults was better than that of nonages. Throughout spring, summer, autumn and winter, the metabolic energy of 4-year adults were 305.77±13.40 kJ/d, 263.67±11.89 kJ/d, 357.23±25.49 kJ/d and 403.12±24.91 kJ/d, respectively, and the nonages were 284.86±17.22 kJ/d, 284. 66±15.16 kJ/d, 402. 26±31.46 kJ/d and 420. 30±31.98 kJ/d, respectively. The minimum metabolic energies were 247.65±21.81 g, 265.86±26.53 g, respectively for each group, detected between 4-year adults and 1-year nonages. Further study is needed to determine whether 29.6 C is the optimal temperature for the Elliot’s pheasant.     

Ecological consequences of global bifurcations in some food chain models

Food chain models of ordinary differential equations (ode’s) are often used in ecology to gain insight in the dynamics of populations of species, and the interactions of these species with each other and their environment. One powerful analysis technique is bifurcation analysis, focusing on the changes in long-term (asymptotic) behaviour under parameter variation. For the detection of local bifurcations there exists standardised software, but until quite recently most software did not include any capabilities for the detection and continuation of global bifurcations. We focus here on the occurrence of global bifurcations in four food chain models, and discuss the implications of their occurrence. In two stoichiometric models (one piecewise continuous, one smooth) there exists a homoclinic bifurcation, that results in the disappearance of a limit cycle attractor. Instead, a stable positive equilibrium becomes the global attractor. The models are also capable of bistability. In two three-dimensional models a Shil’nikov homoclinic bifurcation functions as the organising centre of chaos, while tangencies of homoclinic cycle-to-cycle connections ‘cut’ the chaotic attractors, which is associated with boundary crises. In one model this leads to extinction of the top predator, while in the other model hysteresis occurs. The types of ecological events occurring because of a global bifurcation will be categorized. Global bifurcations are always catastrophic, leading to the disappearance or merging of attractors. However, there is no 1-on-1 coupling between global bifurcation type and the possible ecological consequences. This only emphasizes the importance of including global bifurcations in the analysis of food chain models.