Ghrelin regulates Bax and PCNA but not Bcl-2 expressions following scrotal hyperthermia in the rat

More recently, we have reported the beneficial effects of ghrelin in improvement of histopathological features of the rat testis following local heat exposure. However, the exact mechanism and the precise role of apoptosis- and proliferation-specific proteins in this regeneration process remained to be explored. Thus, thirty adult male Wistar rats were allotted for the experiment and subdivided equally into three groups: control-saline (CS), heat-saline (HS) and heat-ghrelin (HG). The scrota of HS and HG groups were immersed once in water bath at 43 °C for 15 min. HG animals received 2 nmol of ghrelin subcutaneously immediately after heating every other day until day 60 and the other groups were given physiological saline using the same method. The testes of all groups were taken after rat killing on days 30 and 60 after heat treatment for immunocytochemical detection of pro-apoptotic factor Bax, anti-apoptotic protein Bcl-2 and proliferation-associated peptide PCNA in the germ cells. Ghrelin could significantly suppress the Bax expression in spermatocytes compared to the HS group at day 30 (P < 0.05). Likewise, the mean percentages of spermatogonia containing Bax substance were lower in ghrelin-exposed animals, however the differences were not statistically significant. There were immunoreactive cells against Bcl-2 in each germ cell neither in the control nor in the heated animals of experimental groups. In contrast, the number of PCNA immunolabeling cells were higher in HG group in compared to HS or CS animals on both experimental days (P < 0.001). Down-regulation of Bax expression concurrent with overexpression of PCNA in HG group indicates the ability of ghrelin in acceleration of testicular germ cells regeneration following heat stress. These findings indicate that ghrelin may be used as a novel and efficient antioxidant agent to induce resumption of spermatogenesis upon environmental heat exposure.     

A new species and new records of Laelaspis Berlese (Acari, Laelapidae) from Iran

This paper reports on three species of mites of the genus Laelaspis in Iran - Laelaspis calidus Berlese from Pheidole pallidula, Laelaspis humeratus (Berlese) from Tetramorium caespitum and Laelaspis dariusi Joharchi & Jalaeian, sp. n. fromsoil. The new species is described and illustrations provided.     

The effect of ghrelin pretreatment on epididymal sperm quality and tissue antioxidant enzyme activities after testicular ischemia/reperfusion in rats

Ghrelin, the endogenous ligand for growth hormone secretagogue receptor, has been reported to prevent ischemia/reperfusion (I/R) injury in various tissues by its antioxidant activity. Therefore, this study was aimed to investigate the effect of ghrelin on sperm quality and antioxidant enzyme activity in a rat testicular ischemia/reperfusion injury model. Forty-two male Wistar rats were divided into groups control, I/R, and I/R plus ghrelin. The right testes were rotated 720° for 1 h and were allowed to reperfuse for 4 h and 30 days thereafter. Ghrelin (40 nmol/kg IP) or vehicle (physiological saline) was administrated 15 min before reperfusion. After 4 h of reperfusion, a right orchiectomy was performed to measure the biochemical parameters. In addition, the sperm was collected from the epididymis after 30 days of reperfusion, and sperm characteristics were examined. The malondialdehyde levels of the testis tissues were significantly increased, but a statistically significant decrease was found in the superoxide dismutase, glutathione peroxidase, and catalase activities in the I/R group as compared with the control, indicating I/R injury. The sperm evaluation showed a significant reduction in all characteristics resulted from I/R compared with the control. In the ghrelin-treated group, the malondialdehyde values were significantly lowered, and only enzyme activity of glutathione peroxidase showed significant increases compared with the I/R group. Ghrelin significantly enhanced sperm motility, movement, and concentration but did not prevent I/R-induced reduction in membrane integrity in the testes of rats compared to the I/R group. Our results suggest that ghrelin treatment has a protective role on IR-induced testicular injury, and this effect may be due to its antioxidant properties.     

Regulation of catecholamine-responsive adenylate cyclase activity in rat reticulocyte membranes by endogenous factors General characteristics and resolution into protein and nucleotide components

A 100 000 × g soluble, supernatant fraction obtained from the hemolysate of rat reticulocytes was studied for its effect upon catecholamine-sensitive adenylate cyclase activity in reticulocyte membranes. The supernatant material, devoid of adenylate cyclase activity itself, amplified isoproterenol-dependent activity in responsive membranes and was an essential requirement for the expression of hormone sensitivity in membranes rendered unresponsive to isoproterenol alone. The increment in catecholamine-associated activity conferred upon reticulocyte membranes by the supernatant material was β-adrenergic because it did not affect basal or fluoride-related activity and was completely inhibited by propranolol. Guanine nucleotides were present in the supernatant but could account for only a fraction of the total activity because the supernatant was able to cause greater stimulation than maximal concentrations of GTP and when specified concentrations of exogenous GTP were compared with equivalent nucleotide concentrations in the supernatant, the supernatant always led to greater activity. The supernatant was resolved into protein- and nucleotide-containing components by ion-exchange chromatography. Each component was approximately one-half as active in amplifying catecholamine-dependent adenylate cyclase as the unresolved, crude supernatant material. The activity eluted in the first peak of the DEAE chromatogram was resistant to alkaline phosphatase, sensitive to trypsin, not dialyzable and contained no detectable concentrations of GTP or GDP. In contrast, the activity eluted in the second peak of the DEAE chromatogram was sensitive to alkaline phosphatase, resistant to trypsin, completely dialyzable and contained both GTP (30 μM) and GDP (10 μM) in significant concentrations. Neither the crude supernatant not its two active components affected the binding of [¹²⁵I]-iodohydroxybenzylpindolol to reticulocyte membranes. These observations establish in rat reticulocytes the presence of protein and guanine nucleotide constituents which have independent influences upon the catecholamine-responsive adenylate cyclase of reticulocyte membranes.     

Dominance–diversity relationships in ant communities differ with invasion

The relationship between levels of dominance and species richness is highly contentious, especially in ant communities. The dominance‐impoverishment rule states that high levels of dominance only occur in species‐poor communities, but there appear to be many cases of high levels of dominance in highly diverse communities. The extent to which dominant species limit local richness through competitive exclusion remains unclear, but such exclusion appears more apparent for non‐native rather than native dominant species. Here we perform the first global analysis of the relationship between behavioral dominance and species richness. We used data from 1,293 local assemblages of ground‐dwelling ants distributed across five continents to document the generality of the dominance‐impoverishment rule, and to identify the biotic and abiotic conditions under which it does and does not apply. We found that the behavioral dominance–diversity relationship varies greatly, and depends on whether dominant species are native or non‐native, whether dominance is considered as occurrence or relative abundance, and on variation in mean annual temperature. There were declines in diversity with increasing dominance in invaded communities, but diversity increased with increasing dominance in native communities. These patterns occur along the global temperature gradient. However, positive and negative relationships are strongest in the hottest sites. We also found that climate regulates the degree of behavioral dominance, but differently from how it shapes species richness. Our findings imply that, despite strong competitive interactions among ants, competitive exclusion is not a major driver of local richness in native ant communities. Although the dominance‐impoverishment rule applies to invaded communities, we propose an alternative dominance‐diversification rule for native communities.     

Transcriptional Repressor HIC1 Contributes to Suppressive Function of Human Induced Regulatory T Cells

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Cloning, expression and characterization of two new IgE-binding proteins from the yeast Malassezia sympodialis with sequence similarities to heat shock proteins and manganese superoxide dismutase.

Malassezia sympodialis is an opportunistic yeast that colonizes human skin and may induce IgE and T cell reactivity in patients with atopic eczema/dermatitis syndrome (AEDS). Previously, we have cloned and expressed six recombinant allergens (rMala s 1 and rMala s 5 to rMala s 9) from this yeast. By combining high throughput screening and phage surface display techniques, 27 complete and partial IgE-binding clones of M. sympodialis have been identified. Here we enlarged the panel of recombinant M. sympodialis allergens by RACE-PCR, cloning and nucleotide sequencing to obtain the coding sequences of two new IgE-binding clones. The coding sequences of one of the clones showed similarity to the heat shock protein (HSP) family and the other to manganese superoxide dismutase (MnSOD), and both had a high degree of homology to human counterparts. The coding sequences were expressed in Escherichia coli as six-histidine tagged recombinant proteins and generated products with molecular masses of 86.1 kDa for HSP and 22.4 kDa for MnSOD. Their IgE-binding frequencies were shown to be 69% and 75%, respectively, to 28 sera from AEDS patients with serum IgE to M. sympodialis extract, indicating that HSP and MnSOD are major M. sympodialis allergens. In inhibition immunoblotting, M. sympodialis extract could inhibit the binding of serum IgE from AEDS patients to rHSP and rMnSOD in a concentration-dependent manner. The high frequency of sera from AEDS patients, showing IgE binding to both HSP and MnSOD, indicates that these allergens, designated Mala s 10 and Mala s 11, could play a role in AEDS.     

Probing the biological evaluations of a new designed Pt(II) complex using spectroscopic and theoretical approaches: human hemoglobin as a target

In recent years, using heavy metal compounds such as platinum as anticancer agent is one of the common ways in chemical therapy. In this study, a new anticancer compound of glycine derivatives of Pt(II) complex (amyl-glycine1, 10-phenanthroline Platinum nitrate) was designed, and the biological effects of this novel compound on the alterations in the function and structure of human hemoglobin (Hb) at different temperatures of 25 and 37°C were assessed by applying various spectroscopic (fluorescence and circular dichroism (CD)) and theoretical methods. Fluorescence data indicated the strong ability of Pt(II) complex to quench the intrinsic fluorescence of Hb. The binding constant, number of binding sites, and thermodynamic parameters at two temperatures were calculated, and the results indicated the major possibility of occurring van der Waals force or hydrogen bond interactions in the Pt(II) complex–Hb interaction. For evaluating the alteration of secondary structure of Hb upon interaction with various concentrations of complex, far-UV CD spectra were used and it was observed that in high dose of complex, significant changes were occurred which is indicative of some side effects in overdosing of this complex. On the other hand, the molecular docking results illustrate that are well in agreement in obtaining data with spectroscopy. Above results suggested that using Pt(II) complex as an anticancer agent, model drug in high-dose usage might cause some disordering in structure and function of Hb as well as improve understanding of the side effects of newly designed metal anticancer drugs undergoing.     

Chitosan magnetic nanoparticles for drug delivery systems

The potential of magnetic nanoparticles (MNPs) in drug delivery systems (DDSs) is mainly related to its magnetic core and surface coating. These coatings can eliminate or minimize their aggregation under physiological conditions. Also, they can provide functional groups for bioconjugation to anticancer drugs and/or targeted ligands. Chitosan, as a derivative of chitin, is an attractive natural biopolymer from renewable resources with the presence of reactive amino and hydroxyl functional groups in its structure. Chitosan nanoparticles (NPs), due to their huge surface to volume ratio as compared to the chitosan in its bulk form, have outstanding physico-chemical, antimicrobial and biological properties. These unique properties make chitosan NPs a promising biopolymer for the application of DDSs. In this review, the current state and challenges for the application magnetic chitosan NPs in drug delivery systems were investigated. The present review also revisits the limitations and commercial impediments to provide insight for future works.