Phototactic response and light sensitivity in an epigean and a hypogean population of a barb (Garra barreimiae, Cyprinidae)

We investigated the response of two populations of the barb Garra barreimiae to different light intensities (0.5–2000 lx) from a light source. Adults of both the surface (epigean) and cave (hypogean) G. barreimiae populations show photophobic behavior. A photophobic response in the cave form was seen only at higher light intensities because the cavefish are eyeless and rely on extra-retinal light receptors to detect light. In contrast, juveniles (surface and cave) showed photophilic behavior, and their preference for the photic zone of the test tank decreased with increasing age. We discuss the potential role played by photophobic behavior for the colonization of caves by previously surface-dwelling fishes.     

Microwave-assisted modification of starch for compatibilizing LLDPE/starch blends

Modification of activated cassava starch (S) was performed by using octenyl succinic anhydride (OSA) at different starch/OSA ratios under microwave radiation. FTIR and titration results indicated that, within a reaction time of 7 min, degrees of substitution (DS) of about 0.045 may be achieved with 20% OSA. Subsequently, linear low density polyethylene/starch (LLDPE/S) blends were prepared employing succinylated starches (S-g-OSA) as compatibilizers. The morphology and mechanical properties of LLDPE/S blends with and without compatibilizer were compared. It was observed that the addition of 10% of compatibilizer with respect to the dispersed phase content led to a reduction of the starch phase size and to an improvement of the blends mechanical properties.     

Scanning electron microscopic and X-ray diffraction studies of otoconia in the lizard Podarcis s. sicula

Summary The otoliths of embryos and young animals of the lizard Podarcis s. sicula were studied by X-ray diffraction and scanning electron microscopy. Two types of crystal that give different X-ray diffraction patterns were found in the membranous labyrinth of Podarcis. The crystals consist of calcite or aragonite and are easily distinguished by scanning electron microscopy because of their different morphology. The two calcium carbonate crystal forms are not mixed at random but are present in the embryo from the very beginning in specific sites. The endolymphatic sac contains aragonite crystals while the saccule contains calcite crystals adjacent to the wall, in addition to a preponderance of aragonite crystals. The utricle and lagena contain only calcite crystals. The presence of two crystal forms of calcium carbonate in the membranous labyrinth are discussed in terms of differing genetic and functional significance.     

The cooperation between hMena overexpression and HER2 signalling in breast cancer

hMena and the epithelial specific isoform hMena(11a) are actin cytoskeleton regulatory proteins belonging to the Ena/VASP family. EGF treatment of breast cancer cell lines upregulates hMena/hMena(11a) expression and phosphorylates hMena(11a), suggesting cross-talk between the ErbB receptor family and hMena/hMena(11a) in breast cancer. The aim of this study was to determine whether the hMena/hMena(11a) overexpression cooperates with HER-2 signalling, thereby affecting the HER2 mitogenic activity in breast cancer. In a cohort of breast cancer tissue samples a significant correlation among hMena, HER2 overexpression, the proliferation index (high Ki67), and phosphorylated MAPK and AKT was found and among the molecular subtypes the highest frequency of hMena overexpressing tumors was found in the HER2 subtype. From a clinical viewpoint, concomitant overexpression of HER2 and hMena identifies a subgroup of breast cancer patients showing the worst prognosis, indicating that hMena overexpression adds prognostic information to HER2 overexpressing tumors. To identify a functional link between HER2 and hMena, we show here that HER2 transfection in MCF7 cells increased hMena/hMena(11a) expression and hMena(11a) phosphorylation. On the other hand, hMena/hMena(11a) knock-down reduced HER3, AKT and p44/42 MAPK phosphorylation and inhibited the EGF and NRG1-dependent HER2 phosphorylation and cell proliferation. Of functional significance, hMena/hMena(11a) knock-down reduced the mitogenic activity of EGF and NRG1. Collectively these data provide new insights into the relevance of hMena and hMena(11a) as downstream effectors of the ErbB receptor family which may represent a novel prognostic indicator in breast cancer progression, helping to stratify patients.     

Utilization of Grasses for Potential Biofuel Production and Phytoremediation of Heavy Metal Contaminated Soils

This research focuses on investigating the use of common biofuel grasses to assess their potential as agents of long-term remediation of contaminated soils using lead as a model heavy metal ion. We present evidence demonstrating that switch grass and Timothy grass may be potentially useful for long-term phytoremediation of heavy metal contaminated soils and describe novel techniques to track and remove contaminants from inception to useful product. Enzymatic digestion and thermochemical approaches are being used to convert this lignocellulosic feedstock into useful product (sugars, ethanol, biocrude oil + biochar). Preliminary studies on enzymatic hydrolysis and fast pyrolysis of the Switchgrass materials that were grown in heavy metal contaminated soil and non-contaminated soils show that the presence of lead in the Switchgrass material feedstock does not adversely affect the outcomes of the conversion processes. These results indicate that the modest levels of contaminant uptake allow these grass species to serve as phytoremediation agents as well as feedstocks for biofuel production in areas degraded by industrial pollution.     

A novel cell response triggered by interphase centromere structural instability

Interphase centromeres are crucial domains for the proper assembly of kinetochores at the onset of mitosis. However, it is not known whether the centromere structure is under tight control during interphase. This study uses the peculiar property of the infected cell protein 0 of herpes simplex virus type 1 to induce centromeric structural damage, revealing a novel cell response triggered by centromere destabilization. It involves centromeric accumulation of the Cajal body-associated coilin and fibrillarin as well as the survival motor neuron proteins. The response, which we have termed interphase centromere damage response (iCDR), was observed in all tested human and mouse cells, indicative of a conserved mechanism. Knockdown cells for several constitutive centromere proteins have shown that the loss of centromeric protein B provokes the centromeric accumulation of coilin. We propose that the iCDR is part of a novel safeguard mechanism that is dedicated to maintaining interphase centromeres compatible with the correct assembly of kinetochores, microtubule binding, and completion of mitosis.     

Starvation survival of Gordonia polyisoprenivorans CCT 7137, isolated from contaminated groundwater in Brazil

Gordonia polyisoprenivorans CCT7137, exopolysaccharide-producing bacterium, was isolated from groundwater contaminated with leachate in a former municipal landfill site (São Paulo, Brazil). The strain was submitted to starvation in phosphate-buffered saline solution for 56 days so as to evaluate its behavior regarding cuturability and cell morphology. As a response to starvation, G. polyisoprenivorans CCT7137 presented reduction in viable cell count, cell size and cell shape alteration. The initial number of viable cells was 1.51 × 10⁷ c.f.u. ml. After 7 days of starvation culturability dropped to 13.70% (2.07 × 10⁶ c.f.u/ml) and, after 56 days, to 3.25% (4.93 × 10⁵ c.f.u/ml). It was also observed that after 7 days of starvation the cell size presented an average reduction in the values of length, length/width ratio, volume and area of 50, 58, 40 and 42%, respectively. The length/width ratio showed a change of shape from rod to coccobacillus. Changes in cell dimensions and distribution of cell into classes were not significant after day 7 of starvation. The results obtained show that it is not necessary for the strain to starve for more than a week to obtain G. polyisoprenivorans CCT7137 size- reduced cells. The results also indicate the potential for its starved forms to be used in future tests in porous medium to study the production of exopolysaccharide in situ.     

Alterations in CDH15 and KIRREL3 in Patients with Mild to Severe Intellectual Disability

Cell-adhesion molecules play critical roles in brain development, as well as maintaining synaptic structure, function, and plasticity. Here we have found the disruption of two genes encoding putative cell-adhesion molecules, CDH15 (cadherin superfamily) and KIRREL3 (immunoglobulin superfamily), by a chromosomal translocation t(11;16) in a female patient with intellectual disability (ID). We screened coding regions of these two genes in a cohort of patients with ID and controls and identified four nonsynonymous CDH15 variants and three nonsynonymous KIRREL3 variants that appear rare and unique to ID. These variations altered highly conserved residues and were absent in more than 600 unrelated patients with ID and 800 control individuals. Furthermore, in vivo expression studies showed that three of the CDH15 variations adversely altered its ability to mediate cell-cell adhesion. We also show that in neuronal cells, human KIRREL3 colocalizes and interacts with the synaptic scaffolding protein, CASK, recently implicated in X-linked brain malformation and ID. Taken together, our data suggest that alterations in CDH15 and KIRREL3, either alone or in combination with other factors, could play a role in phenotypic expression of ID in some patients.     

The succinate receptor GPR91 in neurons has a major role in retinal angiogenesis

Vascularization is essential for tissue development and in restoration of tissue integrity after an ischemic injury. In studies of vascularization, the focus has largely been placed on vascular endothelial growth factor (VEGF), yet other factors may also orchestrate this process. Here we show that succinate accumulates in the hypoxic retina of rodents and, via its cognate receptor G protein-coupled receptor-91 (GPR91), is a potent mediator of vessel growth in the settings of both normal retinal development and proliferative ischemic retinopathy. The effects of GPR91 are mediated by retinal ganglion neurons (RGCs), which, in response to increased succinate levels, regulate the production of numerous angiogenic factors including VEGF. Accordingly, succinate did not have proangiogenic effects in RGC-deficient rats. Our observations show a pathway of metabolite signaling where succinate, acting through GPR91, governs retinal angiogenesis and show the propensity of RGCs to act as sensors of ischemic stress. These findings provide a new therapeutic target for modulating revascularization.