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This page shows you the most recent publications within this specialty of the MedWorm directory. This is page number 34.

Dust from hog confinement facilities impairs Ca2+ mobilization from sarco(endo)plasmic reticulum by inhibiting ryanodine receptors
This study assessed whether the dust generated inside hog confinement facilities contains compounds that alter Ca2+ mobilization via ryanodine receptors (RyRs), key intracellular channels responsible for mobilizing Ca2+ from internal stores to elicit an array of physiologic functions. Hog barn dust (HBD) was extracted with phosphate-buffered saline, sterile-filtered (0.22 μm), and size-separated using Sephadex G-100 resin. Fractions (F) 1 through 9 (Mw >10,000 Da) had no measurable effects on RyR isoforms. However, F10 through F17, which contained compounds of Mw ≤2,000 Da, modulated the [3H]ryanodine binding to R...
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Tian, C., Moore, C. J., Dodmane, P., Shao, C. H., Romberger, D. J., Toews, M. L., Bidasee, K. R. Tags: ARTICLES Source Type: research

Implications of complex anatomical junctions on conductance catheter measurements of coronary arteries
The objective here is to determine how such geometric variations affect the cross-sectional area (CSA) estimates obtained using the cylindrical model. Computer simulations and in vitro and in vivo experiments were used to assess how the electric field and associated CSA measurement accuracy are affected by three typical in vivo conditions: 1) a vessel with abrupt change in lumen diameter (e.g., transition from aorta to coronary ostia); 2) a vessel with a T-bifurcation or a Y-bifurcation; and 3) a vessel curvature, such as in the right coronary artery, aorta, or pulmonary artery. The error in diameter from simulation result...
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Choi, H. W., Zhang, Z.-D., Farren, N. D., Kassab, G. S. Tags: ARTICLES Source Type: research

Electromagnetic fields enhance chondrogenesis of human adipose-derived stem cells in a chondrogenic microenvironment in vitro
We tested the hypothesis that electromagnetic field (EMF) stimulation enhances chondrogenesis in human adipose-derived stem cells (ADSCs) in a chondrogenic microenvironment. A two-dimensional hyaluronan (HA)-coated well (2D-HA) and a three-dimensional pellet culture system (3D-pellet) were used as chondrogenic microenvironments. The ADSCs were cultured in 2D-HA or 3D-pellet, and then treated with clinical-use pulse electromagnetic field (PEMF) or the innovative single-pulse electromagnetic field (SPEMF) stimulation. The cytotoxicity, cell viability, and chondrogenic and osteogenic differentiations were analyzed after PEMF ...
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Chen, C.-H., Lin, Y.-S., Fu, Y.-C., Wang, C.-K., Wu, S.-C., Wang, G.-J., Eswaramoorthy, R., Wang, Y.-H., Wang, C.-Z., Wang, Y.-H., Lin, S.-Y., Chang, J.-K., Ho, M.-L. Tags: ARTICLES Source Type: research

Effects of caffeine and/or nasal CPAP treatment on laryngeal chemoreflexes in preterm lambs
Current knowledge suggests that laryngeal chemoreflexes (LCR) are involved in the occurrence of certain neonatal apneas/bradycardias, especially in the preterm newborn. While caffeine and/or nasal continuous positive airway pressure (nCPAP) are the most frequent options used for treating apneas in preterm newborns, their effects on LCR-related apneas/bradycardias are virtually unknown. The aim of the present study was to test the hypothesis that caffeine and/or nCPAP decreases LCR-related cardiorespiratory inhibition in a preterm ovine model. Seven preterm lambs were born vaginally on gestational day 133 (normal gestation:...
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Boudaa, N., Samson, N., Carriere, V., Germim, P. S., Pasquier, J.-C., Bairam, A., Praud, J.-P. Tags: ARTICLES Source Type: research

Impact of brief exercise on peripheral blood NK cell gene and microRNA expression in young adults
Natural killers (NK) cells are unique innate immune cells that increase up to fivefold in the circulating blood with brief exercise and are known to play a key role in first-response defense against pathogens and cancer immunosurveillance. Whether exercise alters NK cell gene and microRNA (miRNA) expression is not known. Thirteen healthy men (20–29 yr old) performed ten 2-min bouts of cycle ergometer exercise at a constant work equivalent to an average of 77% of maximum O2 consumption interspersed with 1-min rest. Blood was drawn before and immediately after the exercise challenge. NK cells were isolated from periphe...
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Radom-Aizik, S., Zaldivar, F., Haddad, F., Cooper, D. M. Tags: ARTICLES Source Type: research

Effect of altered arterial perfusion pressure on vascular conductance and muscle blood flow dynamic response during exercise in humans
Changes in vascular conductance (VC) are required to counter changes in muscle perfusion pressure (MPP) to maintain muscle blood flow (MBF) during exercise. We investigated the recruitment of VC as a function of peak VC measured in three body positions at two different work rates to test the hypothesis that adaptations in VC compensated changes in MPP at low-power output (LPO), but not at high-power output (HPO). Eleven healthy volunteers exercised at LPO and HPO (repeated plantar flexion contractions at 20–30% maximal voluntary contraction, respectively) in horizontal (HOR), 35° head-down tilt (HDT), and 45°...
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Villar, R., Hughson, R. L. Tags: ARTICLES Source Type: research

Influence of intermittent hypoxic training on muscle energetics and exercise tolerance
Intermittent hypoxic training (IHT) is sometimes used by athletes to enhance nonhematological physiological adaptations to simulated altitude. We investigated whether IHT would result in greater improvements in muscle energetics and exercise tolerance compared with work-matched intermittent normoxic training (INT). Nine physically active men completed 3 wk of intensive, single-leg knee-extensor exercise training. Each training session consisted of 25 min of IHT (FiO2 14.5 ± 0.1%) with the experimental leg and 25 min of INT with the alternate leg, which served as a control. Before and after the training intervention,...
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Holliss, B. A., Fulford, J., Vanhatalo, A., Pedlar, C. R., Jones, A. M. Tags: ARTICLES Source Type: research

Body fat does not affect venous bubble formation after air dives of moderate severity: theory and experiment
For over a century, studies on body fat (BF) in decompression sickness and venous gas embolism of divers have been inconsistent. A major problem is that age, BF, and maximal oxygen consumption (Vo2max) show high multicollinearity. Using the Bühlmann model with eight parallel compartments, preceded by a blood compartment in series, nitrogen tensions and loads were calculated with a 40 min/3.1 bar (absolute) profile. Compared with Haldanian models, the new model showed a substantial delay in N2 uptake and (especially) release. One hour after surfacing, an increase of 14–28% in BF resulted in a whole body increase ...
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Schellart, N. A. M., van Rees Vellinga, T. P., van Hulst, R. A. Tags: ARTICLES Source Type: research

Adiponectin concentration is associated with muscle insulin sensitivity, AMPK phosphorylation, and ceramide content in skeletal muscles of men but not women
Adiponectin is an adipokine that regulates metabolism and increases insulin sensitivity. Mechanisms behind this insulin-sensitizing effect have been investigated in rodents, but little is known in humans, especially in skeletal muscle. Women have higher serum concentrations of adiponectin than men and are generally more insulin sensitive in skeletal muscle than men. We show here that large differences exist between men and women with regard to apparent adiponectin regulation of insulin-stimulated glucose uptake in skeletal muscle. Serum adiponectin was significantly associated with leg glucose uptake in healthy, young, lea...
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Hoeg, L. D., Sjoberg, K. A., Lundsgaard, A.-M., Jordy, A. B., Hiscock, N., Wojtaszewski, J. F. P., Richter, E. A., Kiens, B. Tags: ARTICLES Source Type: research

Relative effects of submersion and increased pressure on respiratory mechanics, work, and energy cost of breathing
Submersion and increased pressure (depth) characterize the diving environment and may independently increase demand on the respiratory system. To quantify changes in respiratory mechanics, this study employed a unique protocol and techniques to measure, in a hyperbaric chamber, inspiratory and expiratory alveolar pressures (interrupter technique), inspiratory and expiratory resistance in the airways (RawI and RawE, esophageal balloon technique), nitric oxide elimination (thought to correlate with Raw), inspiratory and expiratory mechanical power of breathing, and the total energy cost of ventilation. Eight healthy adult me...
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Held, H. E., Pendergast, D. R. Tags: ARTICLES Source Type: research

Critical role for free radicals on sprint exercise-induced CaMKII and AMPK{alpha} phosphorylation in human skeletal muscle
In conclusion, RNOS play a crucial role in AMPK-mediated signaling after sprint exercise in human skeletal muscle. Antioxidant ingestion 2 h before sprint exercise abrogates the Thr172-AMPKα phosphorylation response observed after the ingestion of placebo by reducing CaMKII and increasing Ser485-AMPKα1/Ser491-AMPKα2 phosphorylation. Sprint performance, muscle metabolism, and AMP-to-ATP and NAD+-to-NADH.H+ ratios are not affected by the acute ingestion of antioxidants.
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Morales-Alamo, D., Ponce-Gonzalez, J. G., Guadalupe-Grau, A., Rodriguez-Garcia, L., Santana, A., Cusso, R., Guerrero, M., Dorado, C., Guerra, B., Calbet, J. A. L. Tags: ARTICLES Source Type: research

Sarcopenia and a physiologically low respiratory quotient in patients with cirrhosis: a prospective controlled study
Patients with cirrhosis have increased gluconeogenesis and fatty acid oxidation that may contribute to a low respiratory quotient (RQ), and this may be linked to sarcopenia and metabolic decompensation when these patients are hospitalized. Therefore, we conducted a prospective study to measure RQ and its impact on skeletal muscle mass, survival, and related complications in hospitalized cirrhotic patients. Fasting RQ and resting energy expenditure (REE) were determined by indirect calorimetry in cirrhotic patients (n = 25), and age, sex, and weight-matched healthy controls (n = 25). Abdominal muscle area was quantified by ...
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Glass, C., Hipskind, P., Tsien, C., Malin, S. K., Kasumov, T., Shah, S. N., Kirwan, J. P., Dasarathy, S. Tags: ARTICLES Source Type: research

Intramicroparticle nitrogen dioxide is a bubble nucleation site leading to decompression-induced neutrophil activation and vascular injury
Inert gases diffuse into tissues in proportion to ambient pressure, and when pressure is reduced, gas efflux forms bubbles due to the presence of gas cavitation nuclei that are predicted based on theory but have never been characterized. Decompression stress triggers elevations in number and diameter of circulating annexin V-coated microparticles (MPs) derived from vascular cells. Here we show that ~10% MPs from wild-type (WT) but not inflammatory nitric oxide synthase-2 (iNOS) knockout (KO) mice increase in size when exposed to elevated air pressure ex vivo. This response is abrogated by a preceding exposure to hydrostati...
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Thom, S. R., Yang, M., Bhopale, V. M., Milovanova, T. N., Bogush, M., Buerk, D. G. Tags: ARTICLES Source Type: research

Exercise pressor response and arterial baroreflex unloading during exercise in chronic kidney disease
Patients with chronic kidney disease (CKD) have poor exercise capacity, which contributes to cardiovascular risk. We sought to determine whether patients with stage 2 or stage 3 CKD have an augmented blood pressure (BP) response during exercise, and if so, whether overactivation of the sympathetic nervous system (SNS) during exercise might play a role. In 13 patients with CKD and hypertension and 13 controls with hypertension, we measured hemodynamics and muscle sympathetic nerve activity (MSNA) during the following maneuvers: low-level rhythmic handgrip (RHG 20%), which primarily stimulates mechanoreceptors, and moderate ...
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Park, J., Quyyumi, A. A., Middlekauff, H. R. Tags: ARTICLES Source Type: research

Effects of eccentric training on mechanical properties of the plantar flexor muscle-tendon complex
Eccentric training is a mechanical loading classically used in clinical environment to rehabilitate patients with tendinopathies. In this context, eccentric training is supposed to alter tendon mechanical properties but interaction with the other components of the muscle-tendon complex remains unclear. The aim of this study was to determine the specific effects of 14 wk of eccentric training on muscle and tendon mechanical properties assessed in active and passive conditions in vivo. Twenty-four subjects were randomly divided into a trained group (n = 11) and a control group (n = 13). Stiffness of the active and passive pa...
Source: Journal of Applied Physiology - March 1, 2013 Category: Physiology Authors: Foure, A., Nordez, A., Cornu, C. Tags: ARTICLES Source Type: research

Fetal development of complex autonomic control evaluated from multiscale heart rate patterns
Development of the fetal autonomic nervous system's integrative capacity in relation to gestational age and emerging behavioral pattern is reflected in fetal heart rate patterns. Conventional indices of vagal and sympathetic rhythms cannot sufficiently reflect their complex interrelationship. Universal behavioral indices of developing complex systems may provide additional information regarding the maturating complex autonomic control. We investigated fetal magnetocardiographic recordings undertaken at 10-min intervals in active (n = 248) and quiet (n = 111) states between 22 and 39 wk gestational age. Standard deviation o...
Source: AJP: Regulatory, Integrative and Comparative Physiology - March 1, 2013 Category: Physiology Authors: Hoyer, D., Nowack, S., Bauer, S., Tetschke, F., Rudolph, A., Wallwitz, U., Jaenicke, F., Heinicke, E., Gotz, T., Huonker, R., Witte, O. W., Schleussner, E., Schneider, U. Tags: Hormones, Reproduction and Development Source Type: research

Hypoxic effects on sympathetic vasomotor outflow and blood pressure during exercise with inspiratory resistance
The purpose of the present study was to clarify the influence of inspiratory resistive breathing during exercise under hypoxic conditions on muscle sympathetic nerve activity (MSNA) and blood pressure (BP). Six healthy males completed this study. The subjects performed a submaximal exercise test using a cycle ergometer in a semirecumbent position under normoxic [inspired oxygen fraction (FiO2) = 0.21] and hypoxic (FiO2 = 0.12–0.13) conditions. The subjects carried out two 10-min exercises at 40% peak oxygen uptake [spontaneous breathing for 5 min and voluntary breathing with inspiratory resistance for 5 min (breathin...
Source: AJP: Regulatory, Integrative and Comparative Physiology - March 1, 2013 Category: Physiology Authors: Katayama, K., Yamashita, S., Ishida, K., Iwamoto, E., Koike, T., Saito, M. Tags: Respiration Source Type: research

Hindlimb unloading results in increased predisposition to cardiac arrhythmias and alters left ventricular connexin 43 expression
Hindlimb unloading (HU) is a well-established animal model of cardiovascular deconditioning. Previous data indicate that HU results in cardiac sympathovagal imbalance. It is well established that cardiac sympathovagal imbalance increases the risk for developing cardiac arrhythmias. The cardiac gap junction protein connexin 43 (Cx43) is predominately expressed in the left ventricle (LV) and ensures efficient cell-to-cell electrical coupling. In the current study we wanted to test the hypothesis that HU would result in increased predisposition to cardiac arrhythmias and alter the expression and/or phosphorylation of LV-Cx43....
Source: AJP: Regulatory, Integrative and Comparative Physiology - March 1, 2013 Category: Physiology Authors: Moffitt, J. A., Henry, M. K., Welliver, K. C., Jepson, A. J., Garnett, E. R. Tags: Physical Activity and Inactivity Source Type: research

Dietary protein digestion and absorption are impaired during acute postexercise recovery in young men
Previously, we demonstrated that exercise can cause small intestinal injury, leading to loss of gut barrier function. The functional consequences of such exercise-induced intestinal injury on subsequent food digestion and absorption are unclear. The present study determined the impact of resistance-type exercise on small intestinal integrity and in vivo dietary protein digestion and absorption kinetics. Twenty-four young males ingested 20 g specifically produced intrinsically l-[1-13C]phenylalanine-labeled protein at rest or after performing a single bout of resistance-type exercise. Continuous intravenous infusions with l...
Source: AJP: Regulatory, Integrative and Comparative Physiology - March 1, 2013 Category: Physiology Authors: van Wijck, K., Pennings, B., van Bijnen, A. A., Senden, J. M. G., Buurman, W. A., Dejong, C. H. C., van Loon, L. J. C., Lenaerts, K. Tags: Physical Activity and Inactivity Source Type: research

Reduced mitochondrial ROS, enhanced antioxidant defense, and distinct age-related changes in oxidative damage in muscles of long-lived Peromyscus leucopus
In this study, we measured ROS generation in the young adult animals of the long-lived white-footed mouse, Peromyscus leucopus (maximal life span potential, MLSP = 8 yr) and the common laboratory mouse, Mus musculus (C57BL/6J strain; MLSP = 3.5 yr). Consistent with the hypothesis, our results show that skeletal muscle mitochondria from adult P. leucopus produce less ROS (superoxide and hydrogen peroxide) compared with M. musculus. Additionally, P. leucopus has an increase in the activity of antioxidant enzymes superoxide dismutase 1, catalase, and glutathione peroxidase 1 at young age. P. leucopus compared with M. musculus...
Source: AJP: Regulatory, Integrative and Comparative Physiology - March 1, 2013 Category: Physiology Authors: Shi, Y., Pulliam, D. A., Liu, Y., Hamilton, R. T., Jernigan, A. L., Bhattacharya, A., Sloane, L. B., Qi, W., Chaudhuri, A., Buffenstein, R., Ungvari, Z., Austad, S. N., Van Remmen, H. Tags: Obesity, Diabetes and Energy Homeostasis Source Type: research

High-intensity interval training increases in vivo oxidative capacity with no effect on Pi->ATP rate in resting human muscle
Mitochondrial ATP production is vital for meeting cellular energy demand at rest and during periods of high ATP turnover. We hypothesized that high-intensity interval training (HIT) would increase ATP flux in resting muscle (VPi->ATP) in response to a single bout of exercise, whereas changes in the capacity for oxidative ATP production (Vmax) would require repeated bouts. Eight untrained men (27 ± 4 yr; peak oxygen uptake = 36 ± 4 ml·kg–1·min–1) performed six sessions of HIT (4–6 x 30-s bouts of all-out cycling with 4-min recovery). After standardized meals and a 10-h fast, ...
Source: AJP: Regulatory, Integrative and Comparative Physiology - March 1, 2013 Category: Physiology Authors: Larsen, R. G., Befroy, D. E., Kent-Braun, J. A. Tags: Obesity, Diabetes and Energy Homeostasis Source Type: research

Medullary GABAergic mechanisms contribute to electroacupuncture modulation of cardiovascular depressor responses during gastric distention in rats
Electroacupuncture (EA) at P5–P6 acupoints overlying the median nerves typically reduces sympathoexcitatory blood pressure (BP) reflex responses in eucapnic rats. Gastric distention in hypercapnic acidotic rats, by activating both vagal and sympathetic afferents, decreases heart rate (HR) and BP through actions in the rostral ventrolateral medulla (rVLM) and nucleus ambiguus (NAmb), leading to sympathetic withdrawal and parasympathetic activation, respectively. A GABAA mechanism in the rVLM mediates the decreased sympathetic outflow. The present study investigated the hypothesis that EA modulates gastric distention-i...
Source: AJP: Regulatory, Integrative and Comparative Physiology - March 1, 2013 Category: Physiology Authors: Tjen-A-Looi, S. C., Guo, Z.-L., Li, M., Longhurst, J. C. Tags: Neural Control Source Type: research

The Utility of Copy Number Variation (CNV) in Studies of Hypertension-related Left Ventricular Hypertrophy (LVH): Rationale, Potential and Challenges
The ultimate goal of human genetics is to understand the role of genome variation in elucidating human traits and diseases. Besides single nucleotide polymorphism (SNP), copy number variation (CNV), defined as gains or losses of a DNA segment larger than 1 kb, has recently emerged as an important tool in understanding heritable source of human genomic differences. It has been shown to contribute to genetic susceptibility of various common and complex diseases. Despite a handful of publications, its role in cardiovascular diseases remains largely unknown. Here, we deliberate on the currently available technologies for CNV d...
Source: Molecular Cytogenetics - March 1, 2013 Category: Molecular Biology Authors: Hoh BoonPengKhalid Yusoff Source Type: research

Effects of flow restoration on mussel growth in a Wild and Scenic North American River
Conclusions: Because growth patterns between internal and external processing methods were consistent, we suggest that external processing is an effective method to obtain growth information despite providing inaccurate age information. External processing is advantageous over internal processing due to its non-destructive nature. Applying this information to analyze the influence of the operation change in the hydroelectric dam, we suggest that changing to run-of-the-river/partial peaking operation has benefited the growth of older mussels below the dam.
Source: Saline Systems - March 1, 2013 Category: Molecular Biology Authors: Brandon SansomDaniel HornbachMark HoveJason Kilgore Source Type: research

BiNoM 2.0, a Cytoscape plugin for accessing and analyzing pathways using standard systems biology formats
Conclusions: Here, we provide an in-depth overview of the BiNoM functions, and we also detail novel aspectssuch as the support of the BioPAX Level 3 format and the implementation of a new algorithm for thequantification of pathways for influence networks. At last, we illustrate some of the BiNoM functionson a detailed biological case study of a network representing the G1/S transition of the cell cycle, acrucial cellular process disturbed in most human tumors.
Source: BMC Systems Biology - Latest articles - March 1, 2013 Category: Molecular Biology Authors: Eric BonnetLaurence CalzoneDaniel RoveraGautier StollEmmanuel BarillotAndrei Zinovyev Source Type: research

Continental phylogeography of an ecologically and morphologically diverse neotropical songbird, zonotrichia capensis
Conclusions: The Pleistocene history of the rufous-collared sparrow involved extensive range expansion from a probable Central American origin. Its remarkable morphological and behavioral diversity probably represents recent responses to local conditions overlying deeper patterns of lineage diversity, which are themselves produced by isolation and the history of colonization of South America.
Source: BMC Evolutionary Biology - Latest articles - March 1, 2013 Category: Molecular Biology Authors: Stephen LougheedLeonardo CampagnaJosé DávilaPablo TubaroDarío LijtmaerPaul Handford Source Type: research

Basophilic histamine content and release during venom immunotherapy: Insights by flow cytometry
Conclusions:We introduce a novel technique that enables to assess the effects of venom immunotherapy on basophils. This new technique may help to monitor treatment effects in individual patients and could aid in the development of more efficient and better tolerated immunotherapy protocols. © 2013 International Clinical Cytometry Society
Source: Cytometry Part B: Clinical Cytometry - March 1, 2013 Category: Molecular Biology Authors: S. Nullens, V. Sabato, M. Faber, J. Leysen, C. H. Bridts, L. S. De Clerck, F. H. Falcone, M. Maurer, D. G. Ebo Tags: Original Article Source Type: research

DCJ-Indel sorting revisited
Conclusions: Encoding indels as DCJ operations offers a new insight into why the problem of DCJ-indel sorting isnot ultimately any more difficult than that of sorting by DCJs alone. There is still room for research inthis area, most notably the problem of sorting when the cost of indels is allowed to vary with respectto the cost of a DCJ and we demand a minimum cost transformation of one genome into another.
Source: Algorithms for Molecular Biology - March 1, 2013 Category: Molecular Biology Authors: Phillip Compeau Source Type: research

Implementing the NICE Osteoarthritis Guidelines in Primary Care: A Role for Practice Nurses
Source: Musculoskeletal Care - March 1, 2013 Category: Physiotherapy Authors: K. S. Dziedzic, E. L. Healey, C. J. Main Tags: Editorial Source Type: research

1,3,4‐Thiadiazole and Its Derivatives: A Review on Recent Progress in Biological Activities
Abstract The 1,3,4‐thiadiazole nucleus is one of the most important and well known heterocyclic nuclei, which is a common and integral feature of a variety of natural products and medicinal agents. Thiadiazole nucleus is present as a core structural component in an array of drug categories such as antimicrobial, anti‐inflammatory, analgesic, antiepileptic, antiviral, antineoplastic and antitubercular agents etc. The broad and potent activity of thiadiazole and their derivatives has established them as pharmacologically significant scaffolds. In the present paper, an attempt has been made with recent research findings o...
Source: Chemical Biology and Drug Design - March 1, 2013 Category: Biology Authors: Abhishek Kumar Jain, Simant Sharma, Ankur Vaidya, V. Ravichandran, Ram kishore Agrawal Tags: Review Source Type: research

Function and fate of myofibroblasts after myocardial infarction
The importance of cardiac fibroblasts in the regulation of myocardial remodelling following myocardial infarction (MI) is becoming increasingly recognised. Studies over the last few decades have reinforced the concept that cardiac fibroblasts are much more than simple homeostatic regulators of extracellular matrix turnover, but are integrally involved in all aspects of the repair and remodelling of the heart that occurs following MI. The plasticity of fibroblasts is due in part to their ability to undergo differentiation into myofibroblasts. Myofibroblasts are specialised cells that possess a more contractile and synthetic...
Source: Fibrogenesis and Tissue Repair - March 1, 2013 Category: Biomedical Science Authors: Neil TurnerKaren Porter Source Type: research

Enhanced algal growth rate in a Taylor vortex reactor
In this report it is demonstrated that highly organized and robust toroidal flow structures known as Taylor vortices cause significant increases in the rate of biomass production, efficiency of light utilization, and CO2 uptake, and these effects become more pronounced at higher Reynolds numbers. In light of these findings and previously reported experiments using Taylor vortex flow to culture algae, it is argued that the flashing light effect, rather than mass transport effects, is responsible for the observed increases in the rate of photosynthesis. Biotechnol. Bioeng. © 2013 Wiley Periodicals, Inc.
Source: Biotechnology and Bioengineering - March 1, 2013 Category: Biomedical Science Authors: Bo Kong, Jacqueline V. Shanks, R. Dennis Vigil Tags: Article Source Type: research

Glycans‐by‐design: Engineering bacteria for the biosynthesis of complex glycans and glycoconjugates
Abstract There is an urgent need for new tools that enable a better understanding of the structure, recognition, metabolism, and biosynthesis of glycans as well as the production of biologically important glycans and glycoconjugates. With the discovery of glycoprotein synthesis in bacteria and functional transfer of glycosylation pathways between species, Escherichia coli cells have become a tractable host for both understanding glycosylation and the underlying glycan code of living cells as well as for expressing glycoprotein therapeutics and vaccines. Here, we review recent efforts to harness natural biological pathways ...
Source: Biotechnology and Bioengineering - March 1, 2013 Category: Biomedical Science Authors: Judith H. Merritt, Anne O. Ollis, Adam C. Fisher, Matthew P. DeLisa Tags: Review Source Type: research

Visualizing cellulase activity
Abstract Commercial exploitation of lignocellulose for biotechnological production of fuels and commodity chemicals requires efficient ‐ usually enzymatic ‐ saccharification of the highly recalcitrant insoluble substrate. A key characteristic of cellulose conversion is that the actual hydrolysis of the polysaccharide chains is intrinsically entangled with physical disruption of substrate morphology and structure. This “substrate deconstruction” by cellulase activity is a slow, yet markedly dynamic process that occurs at different length scales from and above the nanometer range. Little is currently known about the ...
Source: Biotechnology and Bioengineering - March 1, 2013 Category: Biomedical Science Authors: Patricia Bubner, Harald Plank, Bernd Nidetzky Tags: Review Source Type: research

Enzyme production by the mixed fungal culture with nano‐shear pretreated biomass and lignocellulose hydrolysis
Abstract Cellulase, xylanase and β‐glucosidase production was studied on novel nano‐shear pretreated corn stover by the mixed fungi culture. The high shear force from a modified Tayor‐Couette nano‐shear mixing reactor efficiently disintegrated corn stover, resulting in a homogeneous watery mash with particles in much reduced size. Scanning electron microscope (SEM) study showed visible mini‐pores on the fiber cell wall surface, which could improve the accessibility of the pretreated corn stover to microorganisms. Mixed fungal culture of Trichoderma reesei (T. reesei) RUT‐C30 and Aspergillus niger (A. niger) pr...
Source: Biotechnology and Bioengineering - March 1, 2013 Category: Biomedical Science Authors: Jue Lu, Rankothge Ranjith Weerasiri, Yan Liu, Wei Wang, Shaowen Ji, Ilsoon Lee Tags: Article Source Type: research

Rhythm of carbon and nitrogen fixation in unicellular cyanobacteria under turbulent and highly aerobic conditions
In this study, we explore the growth and nitrogen fixing potential of this organism under turbulent conditions with volumetric oxygen mass transfer coefficient (KLa) values that are up to 20‐times greater than in shake flasks. In a stirred vessel, the organism grows well in turbulent regime possibly due to a simulated flashing light effect with optimal growth at Reynolds number of approximately 35000. A respiratory burst lasting for about 4 hours creates anoxic conditions intracellularly with near saturating levels of dissolved oxygen in the extracellular media. This is concomitant with complete exhaustion of intracellul...
Source: Biotechnology and Bioengineering - March 1, 2013 Category: Biomedical Science Authors: S Krishnakumar, Sandeep B Gaudana, Ganesh A Viswanathan, Himadri B Pakrasi, Pramod P Wangikar Tags: Article Source Type: research

Laser exposure of gold nanorods can increase neuronal cell outgrowth
Abstract The usage of gold nanoparticles (Au NPs) in biological applications has risen significantly over the last ten years. With the wide variety of chemical and biological functionalization available and their distinctive optical properties, Au NPs are currently used in a range of biological applications including sensing, labelling, drug delivery and imaging applications. Amongst the available particles, gold nanorods (Au NRs) are particularly useful because their optical absorption can be tuned across the visible to near infrared region. Here we present a novel application of Au NRs associated with low power laser exp...
Source: Biotechnology and Bioengineering - March 1, 2013 Category: Biomedical Science Authors: Chiara Paviolo, John W. Haycock, Jiawey Yong, Aimin Yu, Paul R. Stoddart, Sally L. McArthur Tags: Article Source Type: research

Improved polyhydroxybutyrate production by Saccharomyces cerevisiae through the use of the phosphoketolase pathway
In this study, we investigated the effect of engineering the supply of precursor, acetyl‐CoA, and cofactor, NADPH, on the biosynthesis of the bacterial biopolymer polyhydroxybutyrate (PHB), in S. cerevisiae. Supply of acetyl‐CoA was engineered by overexpression of genes from the ethanol degradation pathway or by heterologous expression of the phophoketolase pathway from Aspergillus nidulans. Both strategies improved the production of PHB. Integration of gapN encoding NADP+ glyceraldehyde‐3‐phosphate dehydrogenase from Streptococcus mutans into the genome enabled an increased supply of NADPH resulting in a decrease ...
Source: Biotechnology and Bioengineering - March 1, 2013 Category: Biomedical Science Authors: Kanokarn Kocharin, Verena Siewers, Jens Nielsen Tags: Article Source Type: research

FGF-2 Prevents Cancer Cells from ER Stress-Mediated Apoptosis via Enhancing Proteasome-mediated Nck Degradation
Induction of Endoplasmic Reticulum (ER) stress-mediated apoptosis in cancer cells represents an alternative approach for cancer therapy. Whether fibroblast growth factor 2 (FGF-2)-induced survival signals may interact with ER stress signalling in cancer cells remains elusive. In this work, we showed that pretreatment with FGF-2 decreased the inhibition of DNA synthesis and induction of apoptosis by two different ER stress inducers, tunicamycin (TM) and thapsigargin (TG), in both human hepatoblastoma HepG2 cells and breast cancer MCF-7 cells. Pretreatment with FGF-2 prevented ER stress-mediated apoptosis by decreasing ER st...
Source: BJ Cell - March 1, 2013 Category: Biochemistry Authors: B Li, Z Pi, L liu, B Zhang, X Huang, P Hu, E Chevet, P Yi, J Liu Tags: BJ Signal Source Type: research

Characterisation of a pre-export enzyme-chaperone complex on the twin-arginine transport pathway
The twin-arginine translocation (Tat) system is a protein targeting pathway utilised by prokaryotes and chloroplasts. Tat substrates are produced with distinctive N-terminal signal peptides and are translocated as fully folded proteins. In Escherichia coli Tat-dependent proteins often contain redox cofactors that must be loaded before translocation. Trimethylamine N-oxide reductase (TorA) is a model bacterial Tat substrate and is a molybdenum cofactor-dependent enzyme. Co-ordination of cofactor loading and translocation of TorA is directed by the TorD protein, which is a cytoplasmic chaperone known to physically interact w...
Source: BJ Cell - March 1, 2013 Category: Biochemistry Authors: J M Dow, F Gabel, F Sargent, T Palmer Tags: BJ Structure Source Type: research

Aromatic interactions with naphthylalanine in a β‐hairpin peptide
Stable peptides have been explored as epitope mimics for protein–protein and protein–nucleic acid interactions; however, presentation of a regular structure is critical. Aromatic interactions are ubiquitous and are competent at stabilizing a β‐hairpin fold. The greatest stabilization has been reported from pairs of tryptophan side chains. Naphthylalanine residues are often used as tryptophan replacements, but it is not clear if 1‐naphthylalanine or 2‐naphthylalanine is adequate at replicating the geometry and stability observed with tryptophan aromatic interactions. Herein, a 12‐residue peptide has been constr...
Source: Journal of Peptide Science - March 1, 2013 Category: Biochemistry Authors: Daniel Meyer, Caleb Mutschler, Ian Robertson, Alexandra Batt, Chad Tatko Tags: Research Article Source Type: research

Ovol2 Mediates BMP Function in Cell Fate Decisions [Developmental Biology]
During early embryonic development, bone morphogenetic protein (BMP) signaling is essential for neural/non-neural cell fate decisions. BMP signaling inhibits precocious neural differentiation and allows for proper differentiation of mesoderm, endoderm, and epidermis. However, the mechanisms underlying the BMP pathway-mediated cell fate decision remain largely unknown. Here, we show that the expression of Ovol2, which encodes an evolutionarily conserved zinc finger transcription factor, is down-regulated during neural differentiation of mouse embryonic stem cells. Knockdown of Ovol2 in embryonic stem cells facilitates neura...
Source: Journal of Biological Chemistry - March 1, 2013 Category: Chemistry Authors: Zhang, T., Zhu, Q., Xie, Z., Chen, Y., Qiao, Y., Li, L., Jing, N. Tags: Signal Transduction Source Type: research

S4-S5 Linker and S6 in RyR1 Gating [Computational Biology]
Ryanodine receptor type 1 (RyR1) releases Ca2+ from intracellular stores upon nerve impulse to trigger skeletal muscle contraction. Effector binding at the cytoplasmic domain tightly controls gating of the pore domain of RyR1 to release Ca2+. However, the molecular mechanism that links effector binding to channel gating is unknown due to lack of structural data. Here, we used a combination of computational and electrophysiological methods and cryo-EM densities to generate structural models of the open and closed states of RyR1. Using our structural models, we identified an interface between the pore-lining helix (Tyr-4912�...
Source: Journal of Biological Chemistry - March 1, 2013 Category: Chemistry Authors: Ramachandran, S., Chakraborty, A., Xu, L., Mei, Y., Samso, M., Dokholyan, N. V., Meissner, G. Tags: Molecular Biophysics Source Type: research

Similarities of CALHM1, Connexins, and Pannexins/Innexins [Neurobiology]
CALHM1 (calcium homeostasis modulator 1) forms a plasma membrane ion channel that mediates neuronal excitability in response to changes in extracellular Ca2+ concentration. Six human CALHM homologs exist with no homology to other proteins, although CALHM1 is conserved across >20 species. Here we demonstrate that CALHM1 shares functional and quaternary and secondary structural similarities with connexins and evolutionarily distinct innexins and their vertebrate pannexin homologs. A CALHM1 channel is a hexamer, comprised of six monomers, each of which possesses four transmembrane domains, cytoplasmic amino and carboxyl termi...
Source: Journal of Biological Chemistry - March 1, 2013 Category: Chemistry Authors: Siebert, A. P., Ma, Z., Grevet, J. D., Demuro, A., Parker, I., Foskett, J. K. Tags: Membrane Biology Source Type: research

Hydrophobicity and Insolubility in San1-mediated Degradation [Protein Synthesis and Degradation]
Misfolded proteins present an escalating deleterious challenge to cells over the course of their lifetime. One mechanism the cell possesses to prevent misfolded protein accumulation is their destruction by protein quality control (PQC) degradation systems. In eukaryotes, PQC degradation typically proceeds via multiple ubiquitin-protein ligases that act throughout the cell to ubiquitinate misfolded proteins for proteasome degradation. What the exact feature of misfolding that each PQC ubiquitin-protein ligase recognizes in their substrates remains an open question. Our previous studies of the budding yeast nuclear ubiquitin...
Source: Journal of Biological Chemistry - March 1, 2013 Category: Chemistry Authors: Fredrickson, E. K., Gallagher, P. S., Clowes Candadai, S. V., Gardner, R. G. Tags: Protein Synthesis and Degradation Source Type: research

Allosteric Control of Abl Kinase by SH3/Linker Enhancement [Signal Transduction]
Multidomain kinases such as c-Src and c-Abl are regulated by complex allosteric interactions involving their noncatalytic SH3 and SH2 domains. Here we show that enhancing natural allosteric control of kinase activity by SH3/linker engagement has long-range suppressive effects on the kinase activity of the c-Abl core. Surprisingly, enhanced SH3/linker interaction also dramatically sensitized the Bcr-Abl tyrosine kinase associated with chronic myelogenous leukemia to small molecule inhibitors that target either the active site or the myristic acid binding pocket in the kinase domain C-lobe. Dynamics analyses using hydrogen e...
Source: Journal of Biological Chemistry - March 1, 2013 Category: Chemistry Authors: Panjarian, S., Iacob, R. E., Chen, S., Wales, T. E., Engen, J. R., Smithgall, T. E. Tags: Protein Structure and Folding Source Type: research

Role of the N-terminal Domain in APS Kinase [Plant Biology]
Adenosine 5′-phosphosulfate kinase (APSK) catalyzes the phosphorylation of adenosine 5′-phosphosulfate (APS) to 3′-phosphoadenosine-5′-phosphosulfate (PAPS). Crystallographic studies of APSK from Arabidopsis thaliana revealed the presence of a regulatory intersubunit disulfide bond (Cys86–Cys119). The reduced enzyme displayed improved catalytic efficiency and decreased effectiveness of substrate inhibition by APS compared with the oxidized form. Here we examine the effect of disulfide formation and the role of the N-terminal domain on nucleotide binding using isothermal titration calorimetry (ITC) and steady-stat...
Source: Journal of Biological Chemistry - March 1, 2013 Category: Chemistry Authors: Ravilious, G. E., Westfall, C. S., Jez, J. M. Tags: Enzymology Source Type: research

Catalytic Intermediates in the W188H Mutant of iNOS [Molecular Biophysics]
Nitric-oxide synthase (NOS) catalyzes nitric oxide (NO) synthesis via a two-step process: l-arginine (l-Arg) → N-hydroxy-l-arginine → citrulline + NO. In the active site the heme is coordinated by a thiolate ligand, which accepts a H-bond from a nearby tryptophan residue, Trp-188. Mutation of Trp-188 to histidine in murine inducible NOS was shown to retard NO synthesis and allow for transient accumulation of a new intermediate with a Soret maximum at 420 nm during the l-Arg hydroxylation reaction (Tejero, J., Biswas, A., Wang, Z. Q., Page, R. C., Haque, M. M., Hemann, C., Zweier, J. L., Misra, S., and Stuehr, D. J. (20...
Source: Journal of Biological Chemistry - March 1, 2013 Category: Chemistry Authors: Sabat, J., Egawa, T., Lu, C., Stuehr, D. J., Gerfen, G. J., Rousseau, D. L., Yeh, S.-R. Tags: Enzymology Source Type: research

Vif Alters Processive ssDNA Scanning of APOBEC3G [Immunology]
APOBEC3G is a retroviral restriction factor that can inhibit the replication of human immunodeficiency virus, type 1 (HIV-1) in the absence of the viral infectivity factor (Vif) protein. Virion-encapsidated APOBEC3G can deaminate cytosine to uracil in viral (−)DNA, which leads to hypermutation and inactivation of the provirus. APOBEC3G catalyzes these deaminations processively on single-stranded DNA using sliding and jumping movements. Vif is thought to primarily overcome APOBEC3G through an interaction that mediates APOBEC3G ubiquitination and results in its proteasomal degradation. However, Vif may also inhibit APOBEC3...
Source: Journal of Biological Chemistry - March 1, 2013 Category: Chemistry Authors: Feng, Y., Love, R. P., Chelico, L. Tags: DNA and Chromosomes Source Type: research

A Novel Transition-state Analogue for Lysozyme [Glycobiology and Extracellular Matrices]
4-O-β-Di-N-acetylchitobiosyl moranoline (2) and 4-O-β-tri-N-acetylchitotriosyl moranoline (3) were produced by lysozyme-mediated transglycosylation from the substrates tetra-N-acetylchitotetraose, (GlcNAc)4, and moranoline, and the binding modes of 2 and 3 to hen egg white lysozyme (HEWL) was examined by inhibition kinetics, isothermal titration calorimetry (ITC), and x-ray crystallography. Compounds 2 and 3 specifically bound to HEWL, acting as competitive inhibitors with Ki values of 2.01 × 10−5 and 1.84 × 10−6 m, respectively. From ITC analysis, the binding of 3 was found to be driven by favorable enthalpy chang...
Source: Journal of Biological Chemistry - March 1, 2013 Category: Chemistry Authors: Ogata, M., Umemoto, N., Ohnuma, T., Numata, T., Suzuki, A., Usui, T., Fukamizo, T. Tags: Enzymology Source Type: research