Regulating the human HECT E3 ligases

Ubiquitination, the covalent attachment of ubiquitin to proteins, by E3 ligases of the HECT (homologous to E6AP C terminus) family is critical in controlling diverse physiological pathways. Stringent control of HECT E3 ligase activity and substrate specificity is essential for cellular health, whereas deregulation of HECT E3s plays a prominent role in disease. The cell employs a wide variety of regulatory mechanisms to control HECT E3 activity and substrate specificity. Here, we summarize the current understanding of these regulatory mechanisms that control HECT E3 function. Substrate specificity is generally determined by interactions of adaptor proteins with domains in the N-terminal extensions of HECT E3 ligases. These N-terminal domains have also been found to interact with the HECT domain, resulting in the formation of inhibitory conformations. In addition, catalytic activity of the HECT domain is commonly regulated at the level of E2 recruitment and through HECT E3 oligomerization. The previously mentioned regulatory mechanisms can be controlled through protein–protein interactions, post-translational modifications, the binding of calcium ions, and more. Functional activity is determined not only by substrate recruitment and catalytic activity, but also by the type of ubiquitin polymers catalyzed to the substrate. While this is often determined by the specific HECT member, recent studies demonstrate that HECT E3s can be modulated to alter the type of ubiquitin polymers they catalyze. Insight into these diverse regulatory mechanisms that control HECT E3 activity may open up new avenues for therapeutic strategies aimed at inhibition or enhancement of HECT E3 function in disease-related pathways

Use of Unpalatable Forages by Ruminants: The Influence of Experience with the Biophysical and Social Environment

Unpalatable forage resources (low nutrient density, potentially toxic metabolites) are widespread and represent a challenge for ruminant nutrition, health, and welfare. Our objective was to synthesize the role of biophysical and social experience on the use of unpalatable forages by ruminants, and highlight derived behavioural solutions for the well-being of soils, plants, and animals. Environmental experiences early in life modulate gene expression and promote learning, which alters morpho-physiological and psychological mechanisms that modify behavioural responses and change food and habitat selection. In this process, ruminants can become better adapted to the habitat where they are reared. Moreover, experiential learning provides flexibility in diet selection, which is critical for changing foraging environments. Learned associations between unpalatable and palatable foods, if ingested in appropriate amounts, sequence, and close temporal association, induce the development of preference for the former type of food. In this way, a more uniform use of resources can be achieved from the landscape level down to the individual plant, with the associated benefits to ecosystem integrity and stability. Ruminants can also learn the medicinal benefits of ingesting foods with toxins (e.g., condensed tannins and saponins with antiparasitic properties). This knowledge on behavioural processes can be translated into behavioural applications that provide low-cost solutions to many challenges that producers face in managing sustainable livestock production systems

Chromosome 9: linkage for borderline personality disorder features.

Objective A large-scale twin study implicated genetic influences on borderline personality disorder (BPO) features, with a heritability estimate of 42%. To date, no genome-wide linkage study has been conducted to identify the genomic region(s) containing the quantitative trait loci that influence the manifestation of BPD features. Methods We conducted a family-based linkage study using Merlin regress. The participating families were drawn from the community-based Netherlands Twin Register. The sample consisted of 711 sibling pairs with phenotype and genotype data, and 561 additional parents with genotype data. BPD features were assessed on a quantitative scale. Results Evidence for linkage was found on chromosomes 1, 4, 9, and 18. The highest linkage peak was found on chromosome 9p at marker D9S286 with a logarithm of odds score of 3.548 (empirical P= 0.0001). Conclusion To our knowledge, this is the first linkage study on BPD features and shows that chromosome 9 is the richest candidate for genes influencing BPD. The results of this study will move the field closer to determining the genetic etiology of BPD and may have important implications for treatment programs in the future. Association studies in this region are, however, warranted to detect the actual genes. © 2008 Wolters Kluwer Health|Lippincott Williams & Wilkins

Role of early experience in the development of preference for low-quality food in sheep

Domestic ruminant selectivity induces floristic changes in pasturelands, risking sustainability and limiting the subsequent availability of susceptible plant species. Development of preferences for species of lower nutritional quality may help to overcome those problems. In this study, we tested the hypothesis that early experience of sheep with a low-quality food (LQF) in a nutritional enriched context increases preference for LQF in adulthood. We predicted a higher proportional consumption of LQF in experienced lambs (EL) than in inexperienced lambs (IL) in choice situations involving LQF and alternative foods. Additionally, we determined intake of LQF by EL and IL at different levels of high-quality food (HQF) availability. From 60 to 210 days of age, EL were fed in separated feed bunks mature oat hay (LQF) simultaneously with sunflower meal (SM) and corn grain (CG), whereas IL were fed alfalfa hay (HQF) simultaneously with SM and CG. After exposure, EL and IL were offered LQF in free choice situations involving alternative foods, and also at five levels of HQF availability (100%, 75%, 50%, 25% and 0% of ad libitum intake). Proportional consumption of LQF was lower or similar in EL than IL. Intake of LQF was also lower or similar in EL than IL at all levels of HQF availability, except when the LQF was the only food available. Our results did not support the hypothesis that early experience with a LQF in a nutritional enriched context increases preference for LQF in adulthood. On the contrary, experience with LQF diminished subsequent preference for LQF in adulthood. It is proposed that, in the conditions of our study, continuous comparison between the LQF and the high-quality supplements (CG and SM) during the early exposure period lead to devaluation of LQF by EL through a simultaneous negative contrast effect.Fil: Catanese, Francisco Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Distel, Roberto Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Rodriguez Iglesias, R. M.. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Villalba, J. J.. State University of Utah; Estados Unido

Contribution of Fdh3 and Glr1 to Glutathione Redox State, Stress Adaptation and Virulence in Candida albicans

Acknowledgments: We thank Aaron Mitchell and Dominique Sanglard for providing the C. albicans protein kinase and transposon mutant libraries, and Louise Walker for the strain CAMY203.Peer reviewedPublisher PD

Feasibility of a 12-month-exercise intervention during and after radiation and chemotherapy in cancer patients: impact on quality of life, peak oxygen consumption, and body composition

Background Accumulating evidence suggests that exercise is effective in treating many of the acute and chronic side effects of anti-cancer therapy. A recent meta-analysis supported the use of exercise to prevent or treat fatigue and lymphoedema and to improve functional status in breast cancer patients. Patients and methods This trial was intended as a controlled, prospective feasibility study evaluating the impact of physical exercise (PE) in cancer patients during and after treatment with radio- and chemotherapy. Inclusion criteria were previous or ongoing treatment for cancer, motivation for PE of 0.5-1hour duration at least twice weekly for at least 3 months. Continuation of PE was encouraged thereafter. Every three months the following endpoints were assessed: Peak oxygen consumption as measured by supervised cardiopulmonary exercise test, body composition and quality of life. Results A total of 45 patients were included with a median age of 49 years. Forty were female and five male. Cancer types were: Breast cancer (n = 30/67 %), gastrointestinal cancer (n = 5/12 %), other types (n = 10/22 %). Thirty-eight (84 %) of the patients were included during curative treatment of their disease. Seven (16 %) were considered palliative. Adherence to the PE-programme longer than 6 months was noted for 41/45 (91 %) of the patients. Intensity of PE was thrice weekly in 32/45 (71 %), twice weekly in 11/45 (24 %). Two of 45 patients (5 %) had no PE. Mean peak oxygen consumption increased from 18.8 ± 5.6 ml/min/kg to 20.5 ± 3 ml/min/kg and 19.9 ± 4.7 ml/min/kg at 3 months (p = 0.005) and 12 months (p = 0.003), respectively. Median fat mass decreased from 30.7 ± 15 kg to 28.9 ± 15 kg and 29.5 ± 13 kg at 3 months (p = 0.001) and 12 months (p = 0.017), respectively. Global health status scores increased from a median baseline value of 54.9 ± 16.3 to 66.4 ± 14 % and 68.0 ± 20.3 % at 3 months (p = 0.001) and 12 months (p = 0.002), respectively. Conclusion This exercise programme in cancer patients with 2–3 weekly supervised sessions over three months was well feasible and demonstrated measurable improvement of oxygen consumption, body composition and quality of life. In addition, a 90 %-adherence rate to the PE-programme beyond 6 months was encouraging. Further randomized prospective data in a larger patient population will be collected comparing the impact of two versus four months supervision

Targeting Olfactory Bulb Neurons Using Combined In Vivo Electroporation and Gal4-Based Enhancer Trap Zebrafish Lines

In vivo electroporation is a powerful method for delivering DNA expression plasmids, RNAi reagents, and morpholino anti-sense oligonucleotides to specific regions of developing embryos, including those of C. elegans, chick, Xenopus, zebrafish, and mouse 1. In zebrafish, in vivo electroporation has been shown to have excellent spatial and temporal resolution for the delivery of these reagents 2-7. The temporal resolution of this method is important because it allows for incorporation of these reagents at specific stages in development. Furthermore, because expression from electroporated vectors occurs within 6 hours 7, this method is more timely than transgenic approaches. While the spatial resolution can be extremely precise when targeting a single cell 2, 6, it is often preferable to incorporate reagents into a specific cell population within a tissue or structure. When targeting multiple cells, in vivo electroporation is efficient for delivery to a specific region of the embryo; however, particularly within the developing nervous system, it is difficult to target specific cell types solely through spatially discrete electroporation. Alternatively, enhancer trap transgenic lines offer excellent cell type-specific expression of transgenes 8. Here we describe an approach that combines transgenic Gal4-based enhancer trap lines 8 with spatially discrete in vivo electroporation 7, 9 to specifically target developing neurons of the zebrafish olfactory bulb. The Et(zic4:Gal4TA4,UAS:mCherry)hzm5 (formerly GA80_9) enhancer trap line previously described 8, displays targeted transgenic expression of mCherry mediated by a zebrafish optimized Gal4 (KalTA4) transcriptional activator in multiple regions of the developing brain including hindbrain, cerebellum, forebrain, and the olfactory bulb. To target GFP expression specifically to the olfactory bulb, a plasmid with the coding sequence of GFP under control of multiple Gal4 binding sites (UAS) was electroporated into the anterior end of the forebrain at 24-28 hours post-fertilization (hpf). Although this method incorporates plasmid DNA into multiple regions of the forebrain, GFP expression is only induced in cells transgenically expressing the KalTA4 transcription factor. Thus, by using the GA080_9 transgenic line, this approach led to GFP expression exclusively in the developing olfactory bulb. GFP expressing cells targeted through this approach showed typical axonal projections, as previously described for mitral cells of the olfactory bulb 10. This method could also be used for targeted delivery of other reagents including short-hairpin RNA interference expression plasmids, which would provide a method for spatially and temporally discrete loss-of-function analysis

Neuroprotection by Exogenous and Endogenous Neuregulin-1 in Mouse Models of Focal Ischemic Stroke.

Identifying novel neuroprotectants that can halt or reverse the neurological effects of stroke is of interest to both clinicians and scientists. We and others previously showed the pre-clinical neuroprotective efficacy of neuregulin-1 (NRG-1) in rats following focal brain ischemia. In this study, we examined neuroprotection by exogenous and endogenous NRG-1 using a mouse model of ischemic stroke. C57BL6 mice were subjected to middle cerebral artery occlusion (MCAO) followed by reperfusion. NRG-1 or vehicle was infused intra-arterially (i.a.) or intravenously (i.v.) after MCAO and before the onset of reperfusion. NRG-1 treatment (16 μg/kg; i.a.) reduced cerebral cortical infarct volume by 72% in mice when delivered post-ischemia. NRG-1 also inhibited neuronal injury as measured by Fluoro Jade B labeling and rescued NeuN immunoreactivity in neurons. Neuroprotection by NRG-1 was also observed in mice when administered i.v. (100 μg/kg) in both male and female mice. We investigated whether endogenous NRG-1 was neuroprotective using male and female heterozygous NRG-1 knockout mice (NRG-1+/-) compared with wild-type mice (WT) littermates. NRG-1+/- and WT mice were subjected to MCAO for 45 min, and infarct size was measured 24 h following MCAO. NRG-1+/- mice displayed a sixfold increase in cortical infarct size compared with WT mice. These results demonstrate that NRG-1 treatment mitigates neuronal damage following cerebral ischemia. We further showed that reduced endogenous NRG-1 results in exacerbated neuronal injury in vivo. These findings suggest that NRG-1 represents a promising therapy to treat stroke in human patients

Discontinuous roughage delivery on digestion, rumen metabolism, feed efficiency and liveweight gain of beef steers fed a concentrate diet

Two experiments were carried out to study the effect of feeding a total mixed ration (TMR) compared to feeding the roughage portion of the diet once every two days and separated of the daily delivered concentrate mixture on dry matter intake, nutrient digestibility, ruminal metabolism, feed efficiency and liveweight gain. In Trial 1, thirty beef steers (Braford and Braford × Criollo; initial BW = 259 ± 27 kg) were used in a 69-d feeding trial. Treatments were: total mixed ration (TMR), and the same proportion of ingredients for the ration but roughage offered once every 2-d and separated from the daily delivered concentrate portion of the diet (REOD). Treatments were arranged in a completely randomized design (three pens/ treatment). In both treatments, daily offered ration had on dry matter basis 90% concentrate and 10% grass hay (Setaria italica). Average daily gain (ADG) did not differ among treatment (1013 vs. 1080 g/d for TMR vs. REOD respectively; SEM = 95 g/d). Dry matter intake was greater in TMR compared to REOD (P < 0.01). Gain to feed ratio tended to be better for REOD than TMR (P = 0.07). In Trial 2, four rumen cannulated steers (Braford) were used in an experiment with a crossover design. Treatments were arranged as a 2*2 factorial design, where the first factor consisted of roughage level (RL): (R14) 14% roughage: 86% concentrate and (R7) 7% roughage: 93% concentrate. The second factor was roughage delivery system (RDS; as it was described for Trial 1): TMR and REOD. There were no RL*RDS interactions for intake and digestion (OM, CP, NDF and starch). Both RL were similar for intake and digestion. Roughage delivery system did not significantly affect intake and digestion of OM, CP, NDF, and starch measured by total fecal collection. Total organic acids (TOA), acetate to propionate ratio (A:P), pH, and rumen ammonia concentrations were not affected by RL and RDS. In conclusion, under the conditions of these trials, steers fed a separated roughage source once every 2-d had similar ADG, and tended to be more efficient compared with TMR. Total tract digestibility and rumen environment traits (pH, VFA, and ammonia) were not affected in response to discontinuous roughage delivery.Fil: Arroquy, Jose Ignacio. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucumán-Santiago del Estero; Argentina. Universidad Nacional de Santiago del Estero. Facultad de Agronomía y Agroindustrias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santiago del Estero. Universidad Nacional de Santiago del Estero. Centro de Investigaciones y Transferencia de Santiago del Estero; ArgentinaFil: Nazareno, Mónica Azucena. Universidad Nacional de Santiago del Estero. Facultad de Agronomía y Agroindustrias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santiago del Estero. Universidad Nacional de Santiago del Estero. Centro de Investigaciones y Transferencia de Santiago del Estero; ArgentinaFil: Avila, M.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucumán-Santiago del Estero; ArgentinaFil: Garcia, M.. Universidad Nacional de Santiago del Estero. Facultad de Agronomía y Agroindustrias; ArgentinaFil: Cervetto, J.. Universidad Nacional de Santiago del Estero. Facultad de Agronomía y Agroindustrias; ArgentinaFil: Distel, Roberto Alejandro. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Saravia, J. J.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucumán-Santiago del Estero; Argentin