Sampling Rhyparida nitida Clark (Coleoptera: Chrysomelidae) and symptoms of their damage on sugarcane

Sampling statistics were determined for larvae, pupae and adults of the chrysomelid Rhyparida nitida associated with sugarcane in Australia and for symptoms of their damage. Iwao's patchiness regression was inappropriate for modelling the mean–variance relationships of the insect counts. Taylor's power law was used to model these data and relationships were developed for counts of small, medium and large larvae, all larvae combined, pupae and adults. The mean–variance relationships of counts of live shoots and shoots killed by larvae of R. nitida were modelled using Iwao's patchiness regression; Taylor's power law was not appropriate to either data set. Relationships to determine sample sizes for fixed levels of precision and fixed-precision-level stop lines for sequential sampling of the different stages and live and dead shoots were also developed. Neither the ln(x + 1) transformation nor the Healy and Taylor transformation consistently standardised the mean–variance relationships of insect counts and the appropriate transformation should be selected on a case-by-case basis. Counts of both live and dead shoots were adequately transformed by the Iwao and Kuno transformation.     

Calorie restriction-like effects of 30 days of resveratrol supplementation on energy metabolism and metabolic profile in obese humans

Resveratrol is a natural compound that affects energy metabolism and mitochondrial function and serves as a calorie restriction mimetic, at least in animal models of obesity. Here, we treated 11 healthy, obese men with placebo and 150?mg/day resveratrol (resVida) in a randomized double-blind crossover study for 30?days. Resveratrol significantly reduced sleeping and resting metabolic rate. In muscle, resveratrol activated AMPK, increased SIRT1 and PGC-1α protein levels, increased citrate synthase activity without change in mitochondrial content, and improved muscle mitochondrial respiration on a fatty acid-derived substrate. Furthermore, resveratrol elevated intramyocellular lipid levels and decreased intrahepatic lipid content, circulating glucose, triglycerides, alanine-aminotransferase, and inflammation markers. Systolic blood pressure dropped and HOMA index improved after resveratrol. In the postprandial state, adipose tissue lipolysis and plasma fatty acid and glycerol decreased. In conclusion, we demonstrate that 30?days of resveratrol supplementation induces metabolic changes in obese humans, mimicking the effects of calorie restriction.     

Paradoxical increase in TAG and DAG content parallel the insulin sensitizing effect of unilateral DGAT1 overexpression in rat skeletal muscle

Background

The involvement of muscle triacylglycerol (TAG) storage in the onset of insulin resistance is questioned and the attention has shifted towards inhibition of insulin signalling by the lipid intermediate diacylglycerol (DAG). The enzyme 1,2-acylCoA:diacylglyceroltransferase-1 (DGAT1) esterifies a fatty acyl-CoA on DAG to form TAG. Therefore, the aim of the present study was to investigate if unilateral overexpression of DGAT1 in adult rat Tibialis anterior (TA) muscle will increase conversion of the lipid intermediate DAG into TAG, thereby improving muscle insulin sensitivity.

Methodology/Principal Findings

The DGAT1 gene construct was injected in the left TA muscle of male rats on chow or high-fat (45% kcal) diet for three weeks, followed by application of one 800 V/cm and four 80 V/cm pulses, using the contralateral leg as sham-electroporated control. Seven days after electroporation, muscle specific insulin sensitivity was assessed with a hyperinsulinemic euglycemic clamp using 2-deoxy-[3H]glucose. Here, we provide evidence that unilateral overexpression of DGAT1 in TA muscle of male rats is associated with an increased rather than decreased DAG content. Strikingly, this increase in DAG content was accompanied by improved muscle insulin sensitivity. Interestingly, markers of muscle lipolysis and mitochondrial function were also increased in DGAT1 overexpressing muscle.

Conclusions/Significance

We conclude that unilateral DGAT1 overexpression can rescue insulin sensitivity, possibly by increasing DAG and TAG turnover in skeletal muscle. In case of a proper balance between the supply and oxidation of fatty acids in skeletal muscle, the lipid intermediate DAG may not exert harmful effects on insulin signalling.     

A new electric method for non-invasive continuous monitoring of stroke volume and ventricular volume-time curves

ABSTRACT: BACKGROUND: In this paper a new non-invasive, operator-free, continuous ventricular stroke volume monitoring device (Hemodynamic Cardiac Profiler, HCP) is presented, that measures the average stroke volume (SV) for each period of 20 seconds, as well as ventricular volume-time curves for each cardiac cycle, using a new electric method (Ventricular Field Recognition) with six independent electrode pairs distributed over the frontal thoracic skin. In contrast to existing non-invasive electric methods, our method does not use the algorithms of impedance or bioreactance cardiography. Instead, our method is based on specific 2D spatial patterns on the thoracic skin, representing the distribution, over the thorax, of changes in the applied current field caused by cardiac volume changes during the cardiac cycle. Since total heart volume variation during the cardiac cycle is a poor indicator for ventricular stroke volume, our HCP separates atrial filling effects from ventricular filling effects, and retrieves the volume changes of only the ventricles. METHODS: In-vitro experiments on a post-mortem human heart have been performed to measure the effects of increasing the blood volume inside the ventricles in isolation, leaving the atrial volume invariant (which can not be done in-vivo). These effects have been measured as a specific 2D pattern of voltage changes on the thoracic skin. Furthermore, a working prototype of the HCP has been developed that uses these in-vitro results in an algorithm to decompose voltage changes, that were measured in-vivo by the HCP on the thoracic skin of a human volunteer, into an atrial component and a ventricular component, in almost real-time (with a delay of maximally 39 seconds). The HCP prototype has been tested in-vivo on 7 human volunteers, using G-suit inflation and deflation to provoke stroke volume changes, and LVot Doppler as a reference technique. RESULTS: The in-vitro measurements showed that ventricular filling caused a pattern over the thorax quite distinct from that of atrial filling. The in-vivo tests of the HCP with LVot Doppler resulted in a Pearson's correlation of R = 0.892, and Bland-Altman plotting of SV yielded a mean bias of -1.6 ml and 2SD = 14.8 ml. CONCLUSIONS: The results indicate that the HCP was able to track the changes in ventricular stroke volume reliably. Furthermore, the HCP produced ventricular volume-time curves that were consistent with the literature, and may be a diagnostic tool as well.     

The lipid droplet coat protein perilipin 5 also localizes to muscle mitochondria

Perilipin 5 (PLIN5/OXPAT) is a lipid droplet (LD) coat protein mainly present in tissues with a high fat-oxidative capacity, suggesting a role for PLIN5 in facilitating fatty acid oxidation. Here, we investigated the role of PLIN5 in fat oxidation in skeletal muscle. In human skeletal muscle, we observed that PLIN5 (but not PLIN2) protein content correlated tightly with OXPHOS content and in rat muscle PLIN5 content correlated with mitochondrial respiration rates on a lipid-derived substrate. This prompted us to examine PLIN5 protein expression in skeletal muscle mitochondria by means of immunogold electron microscopy and Western blots in isolated mitochondria. These data show that PLIN5, in contrast to PLIN2, not only localizes to LD but also to mitochondria, possibly facilitating fatty acid oxidation. Unilateral overexpression of PLIN5 in rat anterior tibialis muscle augmented myocellular fat storage without increasing mitochondrial density as indicated by the lack of change in protein content of five components of the OXPHOS system. Mitochondria isolated from PLIN5 overexpressing muscles did not possess increased fatty acid respiration. Interestingly though, (14)C-palmitate oxidation assays in muscle homogenates from PLIN5 overexpressing muscles revealed a 44.8% (P?=?0.05) increase in complete fatty acid oxidation. Thus, in mitochondrial isolations devoid of LD, PLIN5 does not augment fat oxidation, while in homogenates containing PLIN5-coated LD, fat oxidation is higher upon PLIN5 overexpression. The presence of PLIN5 in mitochondria helps to understand why PLIN5, in contrast to PLIN2, is of specific importance in fat oxidative tissues. Our data suggests involvement of PLIN5 in directing fatty acids from the LD to mitochondrial fatty acid oxidation.     

Geometrical models for cardiac MRI in rodents: comparison of quantification of left ventricular volumes and function by various geometrical models with a full-volume MRI data set in rodents

MRI has been proven to be an accurate method for noninvasive assessment of cardiac function. One of the current limitations of cardiac MRI is that it is time consuming. Therefore, various geometrical models are used, which can reduce scan and postprocessing time. It is unclear how appropriate their use is in rodents. Left ventricular (LV) volumes and ejection fraction (EF) were quantified based on 7.0 Tesla cine-MRI in 12 wild-type (WT) mice, 12 adipose triglyceride lipase knockout (ATGL(-/-)) mice (model of impaired cardiac function), and 11 rats in which we induced cardiac ischemia. The LV volumes and function were either assessed with parallel short-axis slices covering the full volume of the left ventricle (FV, gold standard) or with various geometrical models [modified Simpson rule (SR), biplane ellipsoid (BP), hemisphere cylinder (HC), single-plane ellipsoid (SP), and modified Teichholz Formula (TF)]. Reproducibility of the different models was tested and results were correlated with the gold standard (FV). All models and the FV data set provided reproducible results for the LV volumes and EF, with interclass correlation coefficients ≥0.87. All models significantly over- or underestimated EF, except for SR. Good correlation was found for all volumes and EF for the SR model compared with the FV data set (R(2) ranged between 0.59-0.95 for all parameters). The HC model and BP model also predicted EF well (R(2) ≥ 0.85), although proved to be less useful for quantitative analysis. The SP and TF models correlated poorly with the FV data set (R(2) ≥ 0.45 for EF and R(2) ≥ 0.29 for EF, respectively). For the reduction in acquisition and postprocessing time, only the SR model proved to be a valuable method for calculating LV volumes, stroke volume, and EF.     

Asymmetric introgression between sympatric molestus and pipiens forms of Culex pipiens (Diptera: Culicidae) in the Comporta region, Portugal

Background  

Culex pipiens L. is the most widespread mosquito vector in temperate regions. This species consists of two forms, denoted molestus and pipiens, that exhibit important behavioural and physiological differences. The evolutionary relationships and taxonomic status of these forms remain unclear. In northern European latitudes molestus and pipiens populations occupy different habitats (underground vs. aboveground), a separation that most likely promotes genetic isolation between forms. However, the same does not hold in southern Europe where both forms occur aboveground in sympatry. In these southern habitats, the extent of hybridisation and its impact on the extent of genetic divergence between forms under sympatric conditions has not been clarified. For this purpose, we have used phenotypic and genetic data to characterise Cx. pipiens collected aboveground in Portugal. Our aims were to determine levels of genetic differentiation and the degree of hybridisation between forms occurring in sympatry, and to relate these with both evolutionary and epidemiological tenets of this biological group.     

Lysosomal dysfunction in muscle with special reference to glycogen storage disease type II

The importance of proper lysosomal activity in cell and tissue homeostasis is underlined by "experiments of nature", i.e. genetic defects in one of the at least 40 lysosomal enzymes/proteins present in the human cell. The complete lack of 1-4 alpha-glucosidase (glycogen storage disease type II (GSD II) or Pompe disease) is life-threatening. Patients suffering from GSD II commonly die before the age of 2 years because of cardiorespiratory insufficiency. Striated muscle cells appear to be particularly vulnerable in GSD II. The high cytoplasmic glycogen content in muscle cells most likely gives rise to a high rate of glycogen engulfment by the lysosomes. The polysaccharides become subsequently trapped in these organelles when 1-4 alpha-glucosidase activity is absent. During the course of the disease, muscle wasting occurs. It is hypothesised that the gradual loss of muscle mass is caused by a combination of disuse atrophy and lipofuscine-mediated apoptosis of myocytes. Moreover, we hypothesise that in the remaining skeletal muscle cells, longitudinal transmission of force is hampered by swollen lysosomes, clustering of non-contractile material and focal regions with degraded contractile proteins, which results in muscle weakness.     

Serum calcium and magnesium concentrations and the use of a calcium-magnesium-borogluconate solution in the treatment of Friesian mares with retained placenta

The purpose of the present study was to compare serum calcium and magnesium concentrations in mares with or without a retained placenta (RP) and to evaluate treatment of mares with RP with oxytocin versus oxytocin combined with Ca-Mg-borogluconate solution. Blood samples were obtained within 12 h of foaling from Friesian mares with and without an RP (n = 90 and 65, respectively). Serum Ca and Mg concentrations were analyzed by atomic absorption spectrophotometry. In total, we treated 112 cases of RP in 101 Friesian mares by infusion of either oxytocin dissolved in saline solution or oxytocin dissolved in Ca-Mg-borogluconate solution. We defined RP as the failure to expel all or a part of the fetal membranes up to 3 h after delivery of the foal. We defined a positive response to the treatment as the passage of the entire placenta within 2 h after the infusion. Mares with RP had significantly lower serum calcium levels within 12 h of foaling than mares without RP. Serum magnesium levels showed no difference. Sixty-four percent of the mares treated with oxytocin in Ca-Mg-borogluconate solution responded positively to the treatment, compared to 44% of the mares treated with oxytocin in saline solution (P < 0.05).     

Impaired muscular contractile performance and adenine nucleotide handling in creatine kinase-deficient mice

Creatine kinase (CK) forms a small family of isoenzymes playing an important role in maintaining the concentration of ATP and ADP in muscle cells. To delineate the impact of a lack of CK activity, we studied contractile performance during a single maximal tetanic contraction and during 12 repeated tetanic contractions of intact dorsal flexors of CK knockout (CK(-/-)) mice. To investigate the effect on ATP regeneration, muscular high-energy phosphate content was determined at rest, immediately after the contraction series, and after a 60-s recovery period. Maximal torque of the dorsal flexors was significantly lower in CK(-/-) mice than in wild-type animals, i.e., 23.7 +/- 5.1 and 33.3 +/- 6.8 mN. m. g(-1) wet wt, respectively. Lower muscle ATP (20.1 +/- 1.4 in CK(-/-) vs. 28.0 +/- 2.1 micromol/g dry wt in controls) and higher IMP (1.2 +/- 0.5 in CK(-/-) vs. 0.3 +/- 0.1 micromol/g dry wt in controls) levels at the onset of contraction may contribute to the declined contractility in CK(-/-) mice. In contrast to wild-type muscles, ATP levels could not be maintained during the series of 12 tetanic contractions of dorsal flexors of CK(-/-) mice and dropped to 15.5 +/- 2.4 micromol/g dry wt. The significant increase in tissue IMP (2.4 +/- 1.1 micromol/g dry wt) content after the contraction series indicates that ATP regeneration through adenylate kinase was not capable of fully compensating for the lack of CK. ATP regeneration via the adenylate kinase pathway is a likely cause of reduced basal adenine nucleotide levels in CK(-/-) mice.