Diabetes-related changes in the protein composition of rat cerebral microvessels

To determine the effect of diabetes mellitus on cerebral microvessel protein composition, post translational modification of proteins with glucose and malondialdehyde (MDA) was determined and the abundant protein species found in cerebral microvessels isolated from control and streptozotocin-induced diabetic rats were studied. Two dimensional gel electrophoresis and computer assisted densitometry revealed that only one out of 25 quantitated proteins was significantly altered in diabetic rats after 5 weeks of uncontrolled hyperglycemia. The level of glycosylation of cerebral microvessel protein mixture was significantly increased in diabetic rats compared to control rats (168.8±25 vs 109.5±4.8 nmol/mg) (p<0.05). Western blot analysis of cerebral microvessel proteins from diabetic rats using a specific antibody against MDA-modified proteins revealed three protein spots with molecular weights of approximately 60,000 Kd. These were shown not to be contaminants from cerebral tissue or plasma proteins modified with MDA. It is concluded that short duration of streptozotocin-induced diabetes mellitus in rats is associated with some qualitative changes in protein composition of cerebral microvessels. These changes may contribute to the diabetes-related alterations in the blood-brain barrier.     

Cell death: critical control points

Programmed cell death is a distinct genetic and biochemical pathway essential to metazoans. An intact death pathway is required for successful embryonic development and the maintenance of normal tissue homeostasis. Apoptosis has proven to be tightly interwoven with other essential cell pathways. The identification of critical control points in the cell death pathway has yielded fundamental insights for basic biology, as well as provided rational targets for new therapeutics.     

v-Abl signaling disrupts SOCS-1 function in transformed pre-B cells

The v-Abl oncogene activates Jak-Stat signaling during transformation of pre-B cells in mice. Disrupting Jak activation by deleting the Jak binding domain of v-Abl or by expressing a dominant-negative Jak1 decreases v-Abl transformation efficiency. As SOCS-1 is a known potent inhibitor of Jak kinases, the mechanism by which v-Abl bypasses SOCS-1 regulation to constitutively activate Jak kinases was investigated. SOCS-1 is expressed in v-Abl-transformed cells but is unable to inhibit v-Abl-mediated Jak-Stat signaling. In v-Abl transformants, SOCS-1 can inhibit cytokine signals, but it is more efficient at doing so when the cells are treated with STI571, an Abl kinase inhibitor. Downstream effects of v-Abl signaling include phosphorylation of SOCS-1 on nontyrosine residues, disruption of the interaction between SOCS-1 and the Elongin BC complex, and inhibition of SOCS-1-mediated proteasomal targeting of activated Jaks. These findings reveal a mechanism by which Jak-dependent oncogenes may bypass SOCS-1 inhibition.     

Positive regulation of interleukin-4-mediated proliferation by the SH2-containing inositol-5'-phosphatase

The SH2-containing inositol 5'-phosphatase (SHIP) is tyrosine-phosphorylated in response to cytokines such as interleukin (IL)-3, granulocyte-macrophage colony-stimulating factor, and macrophage colony-stimulating factor. SHIP has been shown to modulate negatively these cytokine signalings; however, a potential role in IL-4 signaling remains uncharacterized. It has been recently shown that IL-4 induces tyrosine phosphorylation of SHIP, implicating the phosphatase in IL-4 processes. Tyrosine kinases, Jak1 and Jak3, involved in IL-4 signaling can associate with SHIP, yet only Jak1 can tyrosine-phosphorylate SHIP when co-expressed. In functional studies, cells overexpressing wild type SHIP are found to be hyperproliferative in response to IL-4 in comparison to parental cells. In contrast, cells expressing catalytically inactive form, SHIP(D672A), show reduced proliferation in response to IL-4. These changes in IL-4-induced proliferation correlate with alterations in phosphatidylinositol 3,4,5-triphosphate levels. However, no differential activation of STAT6, Akt, IRS-2, or p70(S6k), in response to IL-4, was observed in these cells. These data suggest that the catalytic activity of SHIP acts in a novel manner to influence IL-4 signaling. In addition, these data support recent findings that suggest there are uncharacterized signaling pathways downstream of phosphatidylinositol 3,4,5-triphosphate.     

Genetic diversity analysis of chrysopidae family (insecta,neuroptera) via molecular markers

In entomology, improvement of molecular methods would be beneficial tools for accurate identification and detecting the genetic diversity of insect species to discover a corroborative evidence for the traditional classification based on morphology. The aim of this study was focused on RAPD-PCR method for distinguishing the genetic diversity between eight species of Chrysopidae family. In current research, many specimens were collected in different locations of Tehran province (Iran), between them 24 specimens were identified. The wing venation, male genitalia and other morphological characters were used for identification and also the sexing of species was recognized with study of external genitalia. Then, the DNA was extracted with CTAB method. The RAPD-PCR method was carried out with twenty random primers. The agarose gel electrophoresis was used for separation of the PCR products. Based on electrophoresis results, 133 bands were amplified and between them, 126 bands were poly-morph and others were mono-morph. Also, among the applied primers, the primers OPA02 with 19 bands and OPA03 with 8 bands were amplified the maximum and minimum of bands, respectively. The results showed that 80.35 and 73.21 % of genetic similarity existed between Chrysopa pallens–Chrysopa dubitans, and between the Chrysoperla kolthoffi and Chrysoperla carnea, respectively. The minimum (45.53 %) of genetic similarity was observed between C. kolthoffi and C. dubitans, and the maximum (0.80 %) was seen between C. pallens and C. dubitans.     

From affinity selection to kinetic selection in Germinal Centre modelling

Affinity maturation is an evolutionary process by which the affinity of antibodies (Abs) against specific antigens (Ags) increases through rounds of B-cell proliferation, somatic hypermutation, and positive selection in germinal centres (GC). The positive selection of B cells depends on affinity, but the underlying mechanisms of affinity discrimination and affinity-based selection are not well understood. It has been suggested that selection in GC depends on both rapid binding of B-cell receptors (BcRs) to Ags which is kinetically favourable and tight binding of BcRs to Ags, which is thermodynamically favourable; however, it has not been shown whether a selection bias for kinetic properties is present in the GC. To investigate the GC selection bias towards rapid and tight binding, we developed an agent-based model of GC and compared the evolution of founder B cells with initially identical low affinities but with different association/dissociation rates for Ag presented by follicular dendritic cells in three Ag collection mechanisms. We compared an Ag collection mechanism based on association/dissociation rates of B-cell interaction with presented Ag, which includes a probabilistic rupture of bonds between the B-cell and Ag (Scenario-1) with a reference scenario based on an affinity-based Ag collection mechanism (Scenario-0). Simulations showed that the mechanism of Ag collection affects the GC dynamics and the GC outputs concerning fast/slow (un)binding of B cells to FDC-presented Ags. In particular, clones with lower dissociation rates outcompete clones with higher association rates in Scenario-1, while remaining B cells from clones with higher association rates reach higher affinities. Accordingly, plasma cell and memory B cell populations were biased towards B-cell clones with lower dissociation rates. Without such probabilistic ruptures during the Ag extraction process (Scenario-2), the selective advantage for clones with very low dissociation rates diminished, and the affinity maturation level of all clones decreased to the reference level.     

PVA based nanofiber containing cellulose modified with graphitic carbon nitride/nettles/trachyspermum accelerates wound healing

Today, bacterial cellulose has received a great deal of attention for its medical applications due to its unique structural properties such as high porosity, good fluid uptake, good strength, and biocompatibility. This study aimed to fabricate and study bacterial cellulose/graphitic carbon nitride/nettles/trachyspermum nanocomposite by immersion and PVA/BC/g-C₃N₄/nettles/trachyspermum nanofiber by electrospinning method as a wound dressing. The g-C₃N₄ and g-C₃N₄ solution were synthesized and then were characterized using Fourier transform infrared, X-ray diffraction, Zeta Potential, and scanning electronic microscope analyzes. Also, the antibacterial properties of the synthesized materials were proved by gram-positive and gram-negative bacteria using the minimum inhibitory concentration method. Besides, the toxicity, migration, and cell proliferation results of the synthesized materials on NIH 3T3 fibroblasts were evaluated using MTT and scratch assays and showed that the BC/PVA/g-C₃N₄/nettles/trachyspermum composite not only had no toxic effect on cells but also contributed to cell survival, cell migration, and proliferation has done. To evaluate the mechanical properties, a tensile strength test was performed on PVA/BC/g-C₃N₄/nettles/trachyspermum nanofibers, and the results showed good strength of the nanocomposite. In addition, in vivo assay, the produced nanofibers were used to evaluate wound healing, and the results showed that these nanofibers were able to accelerate the wound healing process so that after 14 days, the wound healing percentage showed 95%. Therefore, this study shows that PVA/BC/g-C₃N₄/nettles/trachyspermum nanofibers effectively inhibit bacterial growth and accelerate wound healing.     

Phytotoxicity of green synthesized silver nanoparticles on Camelina sativa L

Due to the increased production and release of silver nanoparticles (AgNPs) in the environment, the concerns about the possibility of toxicity and oxidative damage to plant ecosystems should be considered. In the present study, the effects of different concentrations of AgNPs (0, 0.5, 1, 2, 3 and 4 g/L) synthesized using the extract of camelina (Camelina sativa) leaves on the growth and the biochemical traits of camelina seedlings were investigated. The results showed that AgNPs significantly increased Ag accumulation in the roots and shoots which decreased the growth and photosynthetic pigments of camelina seedlings. The highest decrease in the height and total dry weight was observed by 53.1 and 61.8% under 4 g/L AgNPs, respectively over control plants. AgNPs application over 2 g/L enhanced the accumulation of proline, malondialdehyde, hydrogen peroxide and methylglyoxal, and up-regulated the activity of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase) and glyoxalase (glyoxalase I and II) system which indicates oxidative stress induction in camelina seedlings. Moreover, AgNPs reduced ASA and GSH contents and increased DHA and GSSG contents, hence disrupting the redox balance. These results showed that AgNPs at 4 g/L had the most toxic effects on the camelina growth. Therefore, increasing oxidative stress markers and the activity of antioxidant enzymes and enzymes involved in glyoxalase system indicated the oxidative stress induced by AgNPs treatments over 2 g/L as well as the induction of antioxidant defense systems to combat AgNPs-induced oxidative stress.     

Optimization of phytase production by Penicillium purpurogenum GE1 under solid state fermentation by using Box–Behnken design

Phytase production by Penicillium purpurogenum GE1 isolated from soil around bean root nodules was investigated by solid state fermentation (SSF) using mixed substrates consisted of corn cob and corn bran. The SSF conditions were optimized by using one-variable–at-a-time strategy. The optimum conditions for phytase production were at 27 °C, pH 8 and 66% moisture content. The study of different carbon and nitrogen sources revealed that glucose and peptone registered the highest enzyme productivity (92 ± 5.6 U/g ds, 125 ± 4.9 U/g ds). Among different surfactants, maximum phytase productivity was observed with Tween 80 at 0.001 concentrations (170 ± 4.2 U/g ds). A Box–Behnken design was employed to investigate the optimization of the most significant variables affecting the enzyme production. Maximal phytase production was detected after the addition of (g/5 g ds): 0.75 glucose, 0.375 peptone and 0, 01 tween 80. This result represented an improvement in phytase production of 2.6 folds when compared to that previously obtained using the basal medium under the same cultivation conditions. The generated model was found to be very adequate for phytase production (90% accuracy) as the experimental value was 444 ± 3.5 U/g ds compared to 401 U/g ds for the predicted value. In brief, the production of phytase using corn cob and corn bran is a novel and cheap way for the production of this important enzyme and opens a new way for researchers to discover and explore this arena.