Establishment of X-linked Alport syndrome model mice with a Col4a5 R471X mutation

Alport syndrome (AS) is an inherited disorder characterized by glomerular basement membrane (GBM) abnormality and development of chronic kidney disease at an early age. The cause of AS is a genetic mutation in type IV collagen, and more than 80% of patients have X-linked AS (XLAS) with mutation in COL4A5. Although the causal gene has been identified, mechanisms of progression have not been elucidated, and no effective treatment has been developed. In this study, we generated a Col4a5 mutant mouse harboring a nonsense mutation (R471X) obtained from a patient with XLAS using clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated system. Col4a5 mRNA and protein expressions were not observed in the kidneys of hemizygous R471X male mice. R471X mice showed proteinuria and hematuria. Pathology revealed progression of glomerulosclerosis and interstitial fibrosis by age. Electron microscopy identified irregular thickening in GBM accompanied by irregular lamination. These observations were consistent with the clinical and pathological features of patients with AS and other established models. In addition, our mice models develop end-stage renal disease at the median age of 28 weeks, much later compared to previous models much more consistent with clinical course of human XLAS. Our models have advantages for future experiments in regard with treatment for human XLAS.     

Mitochondrial diseases: Drosophila melanogaster as a model to evaluate potential therapeutics

While often presented as a single entity, mitochondrial diseases comprise a wide range of clinical, biochemical and genetic heterogeneous disorders. Among them, defects in the process of oxidative phosphorylation are the most prevalent. Despite intense research efforts, patients are still without effective treatment. An important part of the development of new therapeutics relies on predictive models of the pathology in order to assess their therapeutic potential. Since mitochondrial diseases are a heterogeneous group of progressive multisystemic disorders that can affect any organ at any time, the development of various in vivo models for the different diseases-associated genes defects will accelerate the search for effective therapeutics. Here, we review existing Drosophila melanogaster models for mitochondrial diseases, with a focus on alterations in oxidative phosphorylation, and discuss the potential of this powerful model organism in the process of drug target discovery.This article is part of a Directed Issue entitled: Energy Metabolism Disorders and Therapies.     

The influence of terpinen-4-ol and eucalyptol – The essential oil components - on fungi and plant sterol monolayers

Antifungal and herbicidal activity of terpenes, being the components of the essential oils, is directly related to the incorporation of these compounds into cellular membranes. Thus, the differences in the lipid composition of various pathogenic membranes may be the factor determining the activity of these molecules. One of the class of lipids, which form the membrane environment are sterols. The aim of this work was to compare the effect of two terpenes: terpinen-4-ol and eucalyptol on the monolayers formed by ergosterol and β – sitosterol, which are the components of fungi and plant membranes, respectively. The modifications in the sterol monolayer properties were investigated in the surface pressure-area measurements and penetration studies as well as in a micrometer scale (Brewster angle microscopy experiments) and in nanoscale (GIXD technique). It was evidenced that although at higher surface pressure the terpene molecules are in part removed from the interface, they are able to substantially modify the condensation, morphology and molecular organization of the sterol film. It was also found that the incorporation of terpenes into sterol films is comparable for both sterols, however, β – sitosterol monolayers properties are affected more strongly than ergosterol films. Finally, the analysis of the results of the studies performed on model membrane systems and the results of antimicrobial studies reported in literature, enabled us to suggest that the activity of terpenes depends on the membrane composition and that the sterol concentration may be important from the point of view of antifungal effect of terpinen-4-ol and eucalyptol.     

Mutation rate and pattern of microsatellites in common carp (<Emphasis Type="Italic">Cyprinus carpio</Emphasis> L.)

Microsatellites are popular molecular markers in genetic and evolutionary studies. Their mutational dynamics have been extensively studied in humans and fruit flies, but few data were available in fish. By genotyping 55 individuals of a F1 pedigree, we investigated the mutation rates and patterns of 49 microsatellites in one of the most important fresh water fish species, the common carp (Cyprinus carpio L.). The overall mutation rate of the 49 loci was 5.56×10⁻⁴/locus/generation (95% confidence interval 1.52×10⁻⁴ and 1.63×10⁻³). The change of allele size was between +2 to −5 repeat units, assuming that the mutation allele arose from the parental allele most similar in size to the mutant.     

Assessment of hepatic integrity after ischemic preservation by isolated perfusion in vitro: the role of albumin

Isolated perfusion of rat livers (IPRL) represents an attractive set-up to be used as a an evaluative tool in the easy and reproducible assessment of liver injury, allowing for screening of new approaches to organ preservation without the expenditure of actual transplantation experiments. Depending on the pathology under investigation, controversy exists concerning the inclusion of albumin in the IPRL. The present study evaluates the use of bovine serum albumin (BSA), simultaneously comparing its effect on healthy and ischemically challenged livers in the same model. Rat livers were excised, flushed via portal vein with Histidine-Tryptophan-Ketoglutarate (HTK) solution and preserved for up to 18 h in HTK at 4 degrees C. Perfusion was performed with Krebs-Henseleit buffer with or without addition of 3% BSA. Control preparations were perfused without prior ischemic storage. In the described model, stability of the preparations was documented for up to 120 min of isolated perfusion and addition of 3% BSA had no adverse effects on the viability of nonischemic livers. While liver perfusion without albumin was inappropriate to reveal alterations in parenchymal or vascular integrity after 18 h of cold preservation, albumin in the perfusate significantly and gradually unmasked differences between nonischemic liver preparations and livers stored ischemically for 8 or 18 h. It could be shown that BSA did have a significant modulatory effect on hepatic induction of apoptosis after ischemia in reducing cleavage of caspase 3. The implementation of albumin is advocated since experimental results are pivotally influenced by the presence or absence of this physiologically constitutive compound in the perfusate.     

A mathematical model on the effect of M. denticulata weed on different winter crops

Many weeds interfere with the productivity of wheat and other winter annual crops; however, one common weed Medicago denticulata, appears to have a beneficial effect. An experiment was conducted at Agricultural Experimental Farm of the Indian Statistical Institute, Giridih, Jharkhand to observe the effect of M. denticulata (a legume) on different crops yield of barley (Hordeum vulgare Sensu lato), linseed (Linum usitatissimum L.), Indian mustard [Brassica juncea (L.) Czernj. & Cosson] and wheat (Triticum aestivum L.). The commensalisms interaction was studied, in which one species benefits, while the other is unaffected, between the crops, M. denticulata and other weeds, to observe the role of medicago as biological control agent of other weeds for enhancement of crop productivity. Further, a statistical test was performed to establish the effect of M. denticulata and weed infestations based on one-step Markov structure of the covariance matrix of the biomass. This permitted development of a mathematical model of a crop–M. denticulata–other weeds system and their interactions through direct and indirect competition for resources. Crops yield decreased considerably due to the presence of other weeds, while it increased due to introduction of medicago and hence medicago acted as a controlling agent in a crop–M. denticulata–other weeds system. Our mathematical analysis supported the experimental findings. The model parameters are estimated through a nonlinear least square and stochastic differential equations. Moreover, some thresholds for the growth of medicago population came out from our analysis that may be used as a biological control threshold for the enhancement of crop productivity.     

Concentration Dependent Different Action of Tamoxifen on Membrane Fluidity

Tamoxifen (TAM) is a non-steroidal antiestrogen drug, which is widely used to prevent and treat breast, liver, pancreas and brain cancers. The present work investigates, in detail, the concentration dependent behavior of TAM (varying from 1 mol% to 45 mol%) on membrane fluidity. The differential scanning calorimetry (DSC) studies showed that tamoxifen eliminates the pre-transition and decreases the main phase transition to lower temperatures. Using visible spectroscopy at 440 nm and Fourier transform infrared (FTIR) spectroscopy it was found that membrane dynamics decreases for 1 and 3 mol% tamoxifen in both the gel and liquid crystalline phases. Above these concentrations up to 18–24 mol%, it increases and reaches its maximum values. As tamoxifen concentration was further increased, the membrane dynamics is found to be gradually decreased, although TAM still has fluidifying effect in comparison to pure phospholipid membrane. These findings are important for the effective use of tamoxifen in the cancer therapy to eliminate its dose dependent side effects reported in the literature.     

The effect of size-dependent growth and environmental factors on animal size variability

The origin of variation in animal growth rate and body size is not well understood but central to ecological and evolutionary processes. We develop a relationship that predicts the change in relative body size variation within a cohort will be approximately equal to the relative change in mean per unit size growth rate, when only size-dependent factors affect growth. When modeling cohort growth, relative size variation decreased, remained unchanged, or increased, as a function of growth rate-size scaling relationships, in a predictable manner. We use the approximation to predict how environmental factors (e.g., resource level) affect body size variation, and verified these predictions numerically for a flexible growth model using a wide range of parameter values. We also explore and discuss the assumptions underlying the approximation. We find that factors that similarly affect mean growth rate may differently affect size variation, and competition may increase body size variation without changing size-independent relationships. We discuss implications of our results to the choice of growth equations used in models where body size variation is an important variable or output.     

Body mass distribution and gait mechanics in fat-tailed dwarf lemurs (Cheirogaleus medius) and patas monkeys (Erythrocebus patas)

Most quadrupeds walk with lateral sequence (LS) gaits, where hind limb touchdowns are followed by ipsilateral forelimb touchdowns. Primates, however, typically walk with diagonal sequence (DS) gaits, where hind limb touchdowns are followed by contralateral forelimb touchdowns. Because the use of DS gaits is nearly ubiquitous among primates, understanding gait selection in primates is critical to understanding primate locomotor evolution. The Support Polygon Model [Tomita, M., 1967. A study on the movement pattern of four limbs in walking. J. Anthropol. Soc. Nippon 75, 120-146; Rollinson, J., Martin, R.D., 1981. Comparative aspects of primate locomotion, with special reference to arboreal cercopithecines. Symp. Zool. Soc. Lond. 48, 377-427] argues that primates' use of DS gaits stems from a more caudal position of the whole-body center of mass (COM) relative to other mammals. We tested the predictions of the Support Polygon Model by examining the effects of natural and experimental variations in COM position on gait mechanics in two distantly related primates: fat-tailed dwarf lemurs (Cheirogaleus medius) and patas monkeys (Erythrocebus patas). Dwarf lemur experiments compared individuals with and without a greatly enlarged tail (a feature associated with torpor that can be expected to shift the COM caudally). During patas monkey experiments, we experimentally shifted the COM cranially with the use of a weighted belt (7-12% of body mass) positioned above the scapulae. Examination of limb kinematics revealed changes consistent with systematic deviations in COM position. Nevertheless, footfall patterns changed in a direction contrary to the predictions of the Support Polygon Model in the dwarf lemurs and did not change at all in the patas monkey. These results suggest that body mass distribution is unlikely to be the sole determinant of footfall pattern in primates and other mammals.