The effects of streptozotocin-induced diabetes on brucellosis of rats

It is believed that an infection is more common and runs a more protracted course in people with diabetes. In clinical practice, it is important to be aware of these associations, as the prognosis is often dependent upon prompt recognition and appropriate treatment. To show the course of brucellosis in the diabetic state, a model of Brucella melitensis infection was used in the setting of streptozotocin-induced diabetes in rat. B. melitensis infection proceeded more severely in diabetic rats and the severity of diabetes affected the prognosis. However, no association was found between B. melitensis and insulin using in vitro and in vivo experiments. Our study illustrates that B. melitensis infection in diabetes should be taken seriously.     

The chromate-inducible chrBACF operon from the transposable element TnOtChr confers resistance to chromium(VI) and superoxide

Large-scale industrial use of chromium(VI) has resulted in widespread contamination with carcinogenic chromium(VI). The abilities of microorganisms to survive in these environments and to detoxify chromate require the presence of specific resistance systems. Here we report identification of the transposon-located (TnOtChr) chromate resistance genes from the highly tolerant strain Ochrobactrum tritici 5bvl1 surviving chromate concentrations of >50 mM. The 7,189-bp-long TnOtChr of the mixed Tn21/Tn3 transposon subfamily contains a group of chrB, chrA, chrC, and chrF genes situated between divergently transcribed resolvase and transposase genes. The chrB and chrA genes, but not chrF or chrC, were essential for establishment of high resistance in chromium-sensitive O. tritici. The chr promoter was strongly induced by chromate or dichromate, but it was completely unresponsive to Cr(III), oxidants, sulfate, or other oxyanions. Plasmid reporter experiments identified ChrB as a chromate-sensing regulator of chr expression. Induction of the chr operon suppressed accumulation of cellular Cr through the activity of a chromate efflux pump encoded by chrA. Expression of chrB, chrC, or chrF in an Escherichia coli sodA sodB double mutant restored its aerobic growth in minimal medium and conferred resistance to superoxide-generating agents menadione and paraquat. Nitroblue tetrazolium staining on native gels showed that ChrC protein had superoxide dismutase activity. TnOtChr appears to represent a mobile genetic system for the distribution of the chromate-regulated resistance operon. The presence of three genes protecting against superoxide toxicity should provide an additional survival advantage to TnOtChr-containing cells in the environments with multiple redox-active contaminants.     

A retrospective controlled study of thiol disulfide homeostasis as a novel marker in Crimean Congo hemorrhagic fever

Objectives: Crimean Congo hemorrhagic fever (CCHF) is the second most common hemorrhagic fever worldwide. This study aimed to evaluate the oxidant–antioxidant balance of patients with CCHF by detecting dynamic thiol disulfide homeostasis (TDH), which is a novel oxidative stress marker, and other molecules, including paraoxonase (PON), arylesterase (ARES), ceruloplasmin (CLP), myeloperoxidase (MPO), and catalase.

Methods: This retrospective, cross-sectional, controlled study, which involved patients with CCHF and healthy volunteers, measured dynamic TDH using a novel automated method developed by Erel.

Results: We recruited 69 adult patients with CCHF (31 females, 38 males, median age 46 years). The case fatality rate was 1.49% (1/69). Increased disulfide/native thiol and disulfide/total thiol ratios, decreased total antioxidant status (TAS), and increased total oxidant status (TOS) were found in patients with CCHF. TAS, PON, and ARES values were found to be positively correlated with both native and total thiol levels, whereas TOS and CLP were negatively correlated with both, at a significant level. MPO activity was similar in both groups.

Discussion: This is the first study in the literature to evaluate dynamic TDH in CCHF. TDH shifts to the oxidative side in patients with CCHF, leading to an increase in TOS.     

The progenitor cells of the embryonic telencephalon and the neonatal anterior subventricular zone differentially regulate their cell cycle

For the last 10 years our laboratory has been studying the proliferation, migration and differentiation of neuronal progenitor cells located in the anterior part of the postnatal forebrain subventricular zone (SVZa). SVZa-derived cells possess a number of proliferative characteristics that distinguish them from the other progenitor cells in the central nervous system. This review summarizes our recent findings, in which we compared the pattern of cell cycle inhibitory proteins expressed by the neonatal SVZa to that of telencephalic ventricular zone cells.     

Cyclic di-GMP-dependent Signaling Pathways in the Pathogenic Firmicute Listeria monocytogenes

We characterized key components and major targets of the c-di-GMP signaling pathways in the foodborne pathogen Listeria monocytogenes, identified a new c-di-GMP-inducible exopolysaccharide responsible for motility inhibition, cell aggregation, and enhanced tolerance to disinfectants and desiccation, and provided first insights into the role of c-di-GMP signaling in listerial virulence. Genome-wide genetic and biochemical analyses of c-di-GMP signaling pathways revealed that L. monocytogenes has three GGDEF domain proteins, DgcA (Lmo1911), DgcB (Lmo1912) and DgcC (Lmo2174), that possess diguanylate cyclase activity, and three EAL domain proteins, PdeB (Lmo0131), PdeC (Lmo1914) and PdeD (Lmo0111), that possess c-di-GMP phosphodiesterase activity. Deletion of all phosphodiesterase genes (ΔpdeB/C/D) or expression of a heterologous diguanylate cyclase stimulated production of a previously unknown exopolysaccharide. The synthesis of this exopolysaccharide was attributed to the pssA-E (lmo0527-0531) gene cluster. The last gene of the cluster encodes the fourth listerial GGDEF domain protein, PssE, that functions as an I-site c-di-GMP receptor essential for exopolysaccharide synthesis. The c-di-GMP-inducible exopolysaccharide causes cell aggregation in minimal medium and impairs bacterial migration in semi-solid agar, however, it does not promote biofilm formation on abiotic surfaces. The exopolysaccharide also greatly enhances bacterial tolerance to commonly used disinfectants as well as desiccation, which may contribute to survival of L. monocytogenes on contaminated food products and in food-processing facilities. The exopolysaccharide and another, as yet unknown c-di-GMP-dependent target, drastically decrease listerial invasiveness in enterocytes in vitro, and lower pathogen load in the liver and gallbladder of mice infected via an oral route, which suggests that elevated c-di-GMP levels play an overall negative role in listerial virulence.     

In vivo and in vitro activity of venom from the endoparasitic wasp Pimpla turionellae (L.) (Hymenoptera: Ichneumonidae)

The biological activity of venom from Pimpla turionellae L. (Hymenoptera: Ichneumonidae) was examined in vivo toward larvae and pupae of Galleriae mellonella L. (Lepidoptera: Pyralidae), and in vitro toward bacterial and fungal cultures, as well as cultured insect cells. Pupae of G. mellonella were far more susceptible to the venom than larvae. At low doses of venom [0.1 venom reservoir equivalents (VRE)], pupal abdominal mobility was inhibited within 30 min, and by 24 h, all pupae injected with venom concentrations >0.5 VRE were completely paralyzed. These same doses of venom resulted in an inhibition of adult emergence. Host larvae were far less sensitive to wasp venom as evidenced by all venom injected larvae remaining responsive to mechanical stimulation by 1 h post injection, even at concentrations equivalent to 1 venom reservoir. Eventually (>2 h at 25 degrees C), venom-injected larvae became immobile, then flaccid, and all died within 24 h post-injection. At lower concentrations of wasp venom, the onset of paralysis was delayed by comparison to that evoked by 1 VRE, and few host larvae were able to pupate. Development of host larvae to adult emergence was also reduced in a dose-dependent manner, with eclosion completely prevented at high concentrations (>0.5 VRE) of venom. Venom doses <0.5 VRE did not appear to induce paralysis or alter larval development. When venom was incubated with bacterial or fungal cultures, no antimicrobial activity was detected. However, wasp venom was found to be cytotoxic and cytolytic to cultured cells derived from the cabbage looper Trichoplusia ni Hubner (Lepidoptera: Noctuidae) and the yellow fever mosquito, Aedes aegypti (L.) (Diptera: Culcidae). Though both cell types displayed similar susceptibility in terms of LC50s, the lepidopteran cells responded much more rapidly with regard to the onset of morphological changes and the timing of cell death. A possible mode of action for the venom is discussed.     

Immunization with a tumor-cell-lysate-loaded autologous-antigen-presenting-cell-based vaccine in melanoma

The discoveries of human melanoma-associated antigens in molecular terms have renewed interest in peptide- or peptide- and antigen-presenting-cell (APC)-based cancer vaccines. Considering the limited scope of immunization using defined peptides, we have studied an alternative approach of specific immunization with tumor-lysate-loaded autologous APC (adherent peripheral mononuclear cells cultured in 1000 U granulocyte/macrophage-colony-stimulating factor for 14 days) as a surrogate vaccine. Seventeen patients (11 with active metastatic disease) were intradermally immunized with the vaccine in a phased dose escalation (10⁵–10⁷ cells/injection) monthly for 4 months. Thirteen patients completed all four immunizations showing no toxicity (3 patients had to be taken off study because of progressive disease and 1 patient went off study as a result of myocardial infarction due to multi-vessel coronary artery disease). None has shown any immediate or delayed toxicity attributable to the immunization and none has shown any evidence of autoimmunity. One patient showed a partial regression of a subcutaneous nodule. Thirteen patients are alive after 4+ months to 30+ months (17-month median survival for the group). Nine patients showed evidence of delayed-type hypersensitivity at the vaccine sites. Monitoring of biological response in conventional natural killer or cytolytic T lymphocyte assays with pre- and post-immune peripheral blood lymphocytes revealed no consistent differences. The vaccine-infiltrating lymphocytes (VIL) from nine specimens were adequately expanded following in vitro stimulation with the respective autologous-lysate-loaded APC for phenotypic and functional analyses. Five of the nine ex vivo expanded VIL were predominantly CD8⁺. Evidence of an antigen-specific CD8⁺ T cell response (cytotoxicity and/or tumor necrosis factor production) was detected in three of the five CD8⁺ VIL. These observations suggest that this type of vaccine is feasible, that it has biological activity, and that the approach may be improved through additional strategic manipulations. Received: 27 March 1998 / Accepted: 14 May 1998     

The racialization of Kurdish identity in Turkey

Until the 1990s, the Kurdish issue in Turkey largely involved the Turkish state, an ethnic group and the Kurdistan Workers' Party (PKK). The 2000s witnessed community-level clashes between Kurds and Turks, signalling the Turkish population's rise as an actor in the issue. This paper makes two claims. First, communal clashes indicate that Kurdish identity is not an ethnic identity alone, but is experiencing a racialization process, based on four indicators: emphasis on physical characteristics in the definitions of Kurds; linking Kurdish identity with the absence of certain moral characteristics; the increasing assignment, rather than self-assertion, of Kurdish identity; and discourses of racial extinction. Second, the racialization of Kurdish identity corresponds to historical change in conceptions of diversity. Racialization became possible after a distinct Kurdish identity was recognized but normatively unwelcomed.     

Serine Carboxypeptidase SCPEP1 and Cathepsin A Play Complementary Roles in Regulation of Vasoconstriction via Inactivation of Endothelin-1

The potent vasoconstrictor peptides, endothelin 1 (ET-1) and angiotensin II control adaptation of blood vessels to fluctuations of blood pressure. Previously we have shown that the circulating level of ET-1 is regulated through its proteolytic cleavage by secreted serine carboxypeptidase, cathepsin A (CathA). However, genetically-modified mouse expressing catalytically inactive CathA S190A mutant retained about 10–15% of the carboxypeptidase activity against ET-1 in its tissues suggesting a presence of parallel/redundant catabolic pathway(s). In the current work we provide direct evidence that the enzyme, which complements CathA action towards ET-1 is a retinoid-inducible lysosomal serine carboxypeptidase 1 (Scpep1), a CathA homolog with previously unknown biological function. We generated a mouse strain devoid of both CathA and Scpep1 activities (DD mice) and found that in response to high-salt diet and systemic injections of ET-1 these animals showed significantly increased blood pressure as compared to wild type mice or those with single deficiencies of CathA or Scpep1. We also found that the reactivity of mesenteric arteries from DD mice towards ET-1 was significantly higher than that for all other groups of mice. The DD mice had a reduced degradation rate of ET-1 in the blood whereas their cultured arterial vascular smooth muscle cells showed increased ET-1-dependent phosphorylation of myosin light chain 2. Together, our results define the biological role of mammalian serine carboxypeptidase Scpep1 and suggest that Scpep1 and CathA together participate in the control of ET-1 regulation of vascular tone and hemodynamics.