Changes in Purkinje cell firing and gene expression precede behavioral pathology in a mouse model of SCA2.

Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominantly inherited disorder, which is caused by a pathological expansion of a polyglutamine (polyQ) tract in the coding region of the ATXN2 gene. Like other ataxias, SCA2 most overtly affects Purkinje cells (PCs) in the cerebellum. Using a transgenic mouse model expressing a full-length ATXN2(Q127)-complementary DNA under control of the Pcp2 promoter (a PC-specific promoter), we examined the time course of behavioral, morphologic, biochemical and physiological changes with particular attention to PC firing in the cerebellar slice. Although motor performance began to deteriorate at 8 weeks of age, reductions in PC number were not seen until after 12 weeks. Decreases in the PC firing frequency first showed at 6 weeks and paralleled deterioration of motor performance with progression of disease. Transcription changes in several PC-specific genes such as Calb1 and Pcp2 mirrored the time course of changes in PC physiology with calbindin-28 K changes showing the first small, but significant decreases at 4 weeks. These results emphasize that in this model of SCA2, physiological and behavioral phenotypes precede morphological changes by several weeks and provide a rationale for future studies examining the effects of restoration of firing frequency on motor function and prevention of future loss of PCs

A positive feedback loop linking enhanced mGluR function and basal calcium in spinocerebellar ataxia type 2

Metabotropic glutamate receptor 1 (mGluR1) function in Purkinje neurons (PNs) is essential for cerebellar development and for motor learning and altered mGluR1 signaling causes ataxia. Downstream of mGluR1, dysregulation of calcium homeostasis has been hypothesized as a key pathological event in genetic forms of ataxia but the underlying mechanisms remain unclear. We find in a spinocerebellar ataxia type 2 (SCA2) mouse model that calcium homeostasis in PNs is disturbed across a broad range of physiological conditions. At parallel fiber synapses, mGluR1-mediated excitatory postsynaptic currents (EPSCs) and associated calcium transients are increased and prolonged in SCA2 PNs. In SCA2 PNs, enhanced mGluR1 function is prevented by buffering [Ca 2+ ] at normal resting levels while in wildtype PNs mGluR1 EPSCs are enhanced by elevated [Ca 2+ ]. These findings demonstrate a deleterious positive feedback loop involving elevated intracellular calcium and enhanced mGluR1 function, a mechanism likely to contribute to PN dysfunction and loss in SCA2

THE EFFECTS OF ULTRA-FILTERED MILK CONSUMPTION ON STRENGTH AND PERFORMANCE FOLLOWING RESISTANCE TRAINING IN FEMALE COLLEGIATE ATHLETES

Resistance training is beneficial in the improvement of skeletal muscle functionality. Improvements in performance, increased resistance to injury, and great force production are associated with resistance training. Hypertrophy of skeletal muscle mass is important for improving fitness, decreasing body fat percentage, improvements in whole-body metabolism, and enhancements in quality of life. The ability to recovery properly following subsequent training sessions is critical for maximizing training adaptations. Nutrient supplementation has been previously studied. The supplementation of carbohydrates has been shown to replenish muscle glycogen stores. The consumption of carbohydrates following resistance training benefits muscle protein balance by attenuating muscle protein breakdown. Another commonly consumed supplement is amino acids/protein. Supplementation of protein has demonstrated improvements in body composition (i.e. increased fat free mass), increases in hypertrophy, and muscular strength. Two type of proteins used by individuals that resistance train are whey protein and casein protein. Whey protein is a fast digesting protein that leads to quick stimulation of protein synthesis. Casein protein is a slower digesting protein that also attenuates the breakdown of muscle protein. Milk is a natural product that contains carbohydrates, whey protein, and casein protein. Whole milk, low fat milk (i.e., 1-2%), and fat free milk have shown positive results in the ability to improve muscle protein synthesis, lean body mass, strength gains. Therefore, the purpose of the following dissertation is to compare the effects of higher protein, less sugar content chocolate milk to traditional low fat chocolate milk on adaptations to (1) strength and performance measures and (2) body composition following resistance training

Evidence of reproductive isolation confirms that Apis andreniformis (Smith, 1858) is a separate species from sympatric Apis florea (Fabricius, 1787).

The species Apis andreniformis (Smith, 1858), the small dwarf honey bee of South-east Asia, is recognized as a valid biological species. This recognition is based on distinctive endophallus characteristics in comparison with sympatric Apis florea (Fabricius, 1787). Additionally, scanning electron microscope images of drone basitarsi are presented, as are preliminary comparisons of wing venation

Multivariate morphometric analysis of Apis cerana of southern mainland Asia

Multivariate morphometric analyses were performed on a series of worker honeybees, Apis cerana, representing 557 colonies from all of southern mainland Asia extending from Afghanistan to Vietnam south of the Himalayas. Scores from the principal components analysis revealed five statistically separable but not entirely distinct morphoclusters of bees: (1) the Hindu Kush, Kashmir, N. Myanmar, N. Vietnam and S. China; (2) Himachal Pradesh region of N. India; (3) N. India, Nepal; (4) central and S. Myanmar and Vietnam, Cambodia, Thailand, S. China and peninsular Malaysia; (5) central and S. India. The major morphoclusters are distributed coherently with the different climatic zones of the region. While populations are definable, nomenclatural adjustments remain for the future

Cicada nymphs dominate American black bear diet in a desert riparian area

American black bears are considered dependent on high-elevation forests or other montane habitats in the drylands of western North America. Black bear sign, including that of cubs, was observed throughout the summers of 2015, 2016, and 2018 along a perennial desert river in the Sonoran Desert of Arizona. We analyzed the contents of 21 black bear scats, collected from May to October of 2016 and 2018. Apache cicada nymphs (Diceroprocta apache) were the dominant food item, occurring in 90% of scats and comprising an average of 59% of scat contents. In the process of excavating these nymphs, bears created large areas of turned-over soil, a form of ecosystem engineering with potential implications for soils, vegetation, and fluvial geomorphology. Given that species distributions are shaped by physiological and ecological contexts, as well as anthropogenic legacies, it is possible that black bears once occurred more commonly in desert riparian systems prior to widespread agricultural development, hunting, and dewatering. Although more research is necessary, we suggest that desert riparian systems may be an alternative habitat for black bears. Better understanding the diet and habitat breadth of American black bears is important in the context of increasing landscape fragmentation and militarization in the U.S.-Mexican borderlands