Novel spectral method for the study of viral carcinogenesis in vitro

Fourier transform infrared (FTIR) spectroscopy is a unique technique for the laboratory diagnosis of cellular variations based on the characteristic molecular vibrational spectra of the cells. Microscopic FTIR was used to investigate spectral differences between normal and malignant fibroblasts transformed by retrovirus infection. A detailed analysis showed significant differences between cancerous and normal cells. The contents of vital cellular metabolites were significantly lower in the transformed cells than in the normal cells. In an attempt to identify the cellular components responsible for the observed spectral differences between normal and cancerous cells, we found significant differences between DNA of normal and cancerous cells.     

Inactivation of West-Nile virus during peptic cleavage of horse plasma IgG.

Peptic cleavage of horse plasma IgG is a common procedure for the preparation of F(ab)(2) products for human use, such as antivenin and antitoxin. The removal of the Fc fragment from the IgG molecule by enzymatic cleavage at low pH, ensures fewer side-effects of the F(ab)(2) product for passive immunotherapy compared with the whole IgG molecule. Since the starting material may be contaminated by zoonotic horse viruses, it is necessary to demonstrate the removal or inactivation of possible viral contaminants. Guidelines for performing such studies were published by the Commission for Plasma-Derived Medical Products (CPMP), and updated by the Committee for Proprietary Medical Products. It is recommended that viral clearance studies be performed on scaled down production processes that have been identified as possibly contributing to virus clearance and spiking of a model virus to the starting material. The model virus should be non-pathogenic but closely related to the potential infective virus. By quantifying the amount of virus in the product before and after the production process, the amount of virus cleared can be determined. Log(10) reductions of the order of 4 logs or more, and a biphasic inactivation curve (fast initial phase followed by a slower phase), are indicative of a clearance effect with a particular test virus under investigation.     

Characterization of catechol derivative removal by lignin peroxidase in aqueous mixture

The use of lignin peroxidase (LIP) as an alternative method for the removal of four catechols (1,2-dihydroxybenzene): catechol (CAT), 4-chlorocatechol (4-CC), 4,5-dichlorocatechol (4,5-DCC) and 4-methylcatechol (4-MC) typical pollutants in wastewater derived from oil and paper industries, was evaluated. The removal of 2 mM catecholic substrates by 1 μM LIP after 1 h was in the following order: 4,5-DCC (95%) > 4-CC(90%) > CAT(55%) > 4-MC(43%). Except for 4-MC, all reactions were accompanied by the formation of insoluble products, leading to LIP precipitation. LIP was exposed to soluble or insoluble product-dependent inactivation, depending on the substrates tested, immediately at the start of the reactions. Despite immediate enzyme inactivation, removal of catecholic substrates continued, resulting in oligomeric product formation. Major oxidation products analyzed were compatible with dimeric, trimeric and tetrameric structures. Ether linkages and a benzoquinone structure were detected in two purified oligochlorocatechols.Catechol derivatives removal initiated by LIP, seems to be different for each catecholic substrate in terms of substrate consumption and transformation, and of enzyme activity.     

Reverse hierarchies and sensory learning

Revealing the relationships between perceptual representations in the brain and mechanisms of adult perceptual learning is of great importance, potentially leading to significantly improved training techniques both for improving skills in the general population and for ameliorating deficits in special populations. In this review, we summarize the essentials of reverse hierarchy theory for perceptual learning in the visual and auditory modalities and describe the theory's implications for designing improved training procedures, for a variety of goals and populations.     

Seasonal changes in recombination characteristics in a natural population of Drosophila melanogaster

Environmental seasonality is a potent evolutionary force, capable of maintaining polymorphism, promoting phenotypic plasticity and causing bet-hedging. In Drosophila, environmental seasonality has been reported to affect life-history traits, tolerance to abiotic stressors and immunity. Oscillations in frequencies of alleles underlying fitness-related traits were also documented alongside SNPs across the genome. Here, we test for seasonal changes in two recombination characteristics, crossover rate and crossover interference, in a natural D. melanogaster population from India using morphological markers of the three major chromosomes. We show that winter flies, collected after the dry season, have significantly higher desiccation tolerance than their autumn counterparts. This difference proved to hold also for hybrids with three independent marker stocks, suggesting its genetic rather than plastic nature. Significant between-season changes are documented for crossover rate (in 9 of 13 studied intervals) and crossover interference (in four of eight studied pairs of intervals); both single and double crossovers were usually more frequent in the winter cohort. The winter flies also display weaker plasticity of both recombination characteristics to desiccation. We ascribe the observed differences to indirect selection on recombination caused by directional selection on desiccation tolerance. Our findings suggest that changes in recombination characteristics can arise even after a short period of seasonal adaptation (~8–10 generations).Subject terms: Structural variation, Evolutionary biology, Evolutionary genetics     

Four USH2A founder mutations underlie the majority of Usher syndrome type 2 cases among non-Ashkenazi Jews

Type 2 Usher syndrome (USH2) is a recessively inherited disorder, characterized by the combination of early onset, moderate-to-severe, sensorineural hearing loss, and vision impairment due to retinitis pigmentosa. From 74% to 90% of USH2 cases are caused by mutations of the USH2A gene. USH2A is composed of 72 exons, encoding for usherin, an extracellular matrix protein, which plays an important role in the development and maintenance of neurosensory cells in both retina and cochlea. To date, over 70 pathogenic mutations of USH2A have been reported in individuals of various ethnicities. Many of these mutations are rare private mutations segregating in single families. The aim of the current work was to investigate the genetic basis for USH2 among Jews of various origins. We found that four USH2A mutations (c.239-240insGTAC, c.1000C>T, c.2209C>T, and c.12067-2A>G) account for 64% of mutant alleles underlying USH2 in Jewish families of non-Ashkenazi descent. Considering the very large size of the USH2A gene and the high number of mutations detected in USH2 patients worldwide, our findings have significant implications for genetic counseling and carrier screening in various Jewish populations.     

Genetic carrier screening for spinal muscular atrophy and spinal muscular atrophy with respiratory distress 1 in an isolated population in Israel

Spinal muscular atrophy (SMA) is an autosomal recessive disease characterized by progressive muscle weakness. It is caused by a mutation in the survival motor neuron gene 1 (SMN1) gene. SMA with respiratory distress 1 (SMARD1), an uncommon variant of infantile SMA also inherited in an autosomal recessive manner, is caused by mutations in the immunoglobulin mu-binding protein 2 (IGHMBP2) gene. We carried out genetic carrier screening among the residents of an isolated Israeli Arab village with a high frequency of SMA in order to identify carriers of SMA type I and SMARD1. During 2006, 168 women were tested for SMA, of whom 13.1% were found to be carriers. Of 111 women tested for SMARD1, 9.9% were found to be carriers. Prenatal diagnosis was performed in one couple where both spouses were carriers of SMARD1; the fetus was found to be affected, and the pregnancy was terminated. To the best of our knowledge, this is the first example of the establishment of a large-scale carrier-screening program for SMA and SMARD1 in an isolated population. SMA has a carrier frequency of 1:33-1:60 in most populations and should be considered for inclusion in a population-based genetic-screening program.     

Dual fatty acyl modification determines the localization and plasma membrane targeting of CBL/CIPK Ca2+ signaling complexes in Arabidopsis

Arabidopsis thaliana calcineurin B-like proteins (CBLs) interact specifically with a group of CBL-interacting protein kinases (CIPKs). CBL/CIPK complexes phosphorylate target proteins at the plasma membrane. Here, we report that dual lipid modification is required for CBL1 function and for localization of this calcium sensor at the plasma membrane. First, myristoylation targets CBL1 to the endoplasmic reticulum. Second, S-acylation is crucial for endoplasmic reticulum-to-plasma membrane trafficking via a novel cellular targeting pathway that is insensitive to brefeldin A. We found that a 12-amino acid peptide of CBL1 is sufficient to mediate dual lipid modification and to confer plasma membrane targeting. Moreover, the lipid modification status of the calcium sensor moiety determines the cellular localization of preassembled CBL/CIPK complexes. Our findings demonstrate the importance of S-acylation for regulating the spatial accuracy of Ca2+-decoding proteins and suggest a novel mechanism that enables the functional specificity of calcium sensor/kinase complexes.     

A novel ROP/RAC GTPase effector integrates plant cell form and pattern formation

ROPs/RACs are the only known signaling Ras superfamily small GTPases in plants. As such they have been suggested to function as central regulators of diverse signaling cascades. The ROP/RAC signaling networks are largely unknown, however, because only few of their effector proteins have been identified. In a paper that was published in the June 5, 2007 issue of Current Biology we described the identification of a novel ROP/RAC effector designated ICR1 (Interactor of Constitutive active ROPs 1). We demonstrated that ICR1 functions as a scaffold that interacts with diverse but specific group of proteins including SEC3 subunit of the exocyst vesicle tethering complex. ICR1-SEC3 complexes can interact with ROPs in vivo and are thereby recruited to the plasma membrane. ICR1 knockdown or silencing leads to cell deformation and loss of the root stem cells population, and ectopic expression of ICR1 phenocopies activated ROPs/RACs. ICR1 presents a new paradigm in ROP/RAC signaling and integrates mechanisms regulating cell form and pattern formation at the whole plant level.Key words: Rho, auxin, root development, vesicle trafficking, RAC, ROP, polarity, Arabidopsis, exocyst