The impact of oxidative stress in thiamine deficiency: A multifactorial targeting issue

Thiamine (vitamin B1) deficiency, the underlying cause of Wernicke–Korsakoff syndrome, is associated with the development of focal neuronal loss in vulnerable areas of the brain. Although the actual mechanism(s) that lead to the selective histological lesions characteristic of this disorder remain unresolved, oxidative stress has been shown to play a major role in its pathophysiology. In this review, the multifactorial influence of oxidative stress on a variety of processes known to take part in the development of structural lesions in TD including excitotoxicity, neuroinflammation, blood–brain barrier integrity, mitochondrial integrity, apoptosis, nucleic acid function, and neural stem cells will be discussed, and therapeutic strategies undertaken for treating neurodegeneration examined which may have an impact on the future treatment of this important vitamin deficiency.     

Auxotrophic recombinant Mycobacterium bovis BCG overexpressing Ag85B enhances cytotoxicity on superficial bladder cancer cells in vitro

BCG therapy remains at the forefront of immunotherapy for treating patients with superficial bladder cancer. The high incidence of local side effects and the presence of non-responder diseases have led to efforts to improve the therapy. Hence, we proposed that an auxotrophic recombinant BCG strain overexpressing Ag85B (BCG ?leuD/Ag85B), could enhance the cytotoxicity to the human bladder carcinoma cell line 5637. The rBCG was generated using an expression plasmid encoding the mycobacterial antigen Ag85B to transform a BCG ?leuD strain. The inhibitory effect of BCG ?leuD/Ag85B on 5637 cells was determined by the MTT method, morphology observation and a LIVE/DEAD assay. Gene expression profiles for apoptotic, cell cycle-related and oxidative stress-related genes were investigated by qRT-PCR. Bax, bcl-2 and p53 induction by BCG ?leuD/Ag85B treatment was evaluated by Western blotting. BCG ?leuD/Ag85B revealed a superior cytotoxicity effect compared to the control strains used in this study. The results showed that the expression level of pro-apoptotic and cell cycle-related genes increased after BCG ?leuD/Ag85B treatment, whereas the mRNA levels of anti-apoptotic genes decreased. Interestingly, BCG ?leuD/Ag85B also increased the mRNA level of antioxidant enzymes in the bladder cancer cell line. Bax and p53 proteins levels increased following treatment. In conclusion, these results suggest that treatment with BCG ?leuD/Ag85B enhances cytotoxicity for superficial bladder cancer cells in vitro. Therefore, rBCG therapy may have potential benefits in the treatment of bladder cancer.     

An Evaluation of the Antinociceptive Effects of Phα1β, a Neurotoxin from the Spider Phoneutria nigriventer, and ω-Conotoxin MVIIA, a Cone Snail Conus magus Toxin, in Rat Model of Inflammatory and Neuropathic Pain

Voltage-sensitive calcium channels (VSCCs) underlie cell excitability and are involved in the mechanisms that generate and maintain neuropathic and inflammatory pain. We evaluated in rats the effects of two VSCC blockers, ω-conotoxin MVIIA and Phα1β, in models of inflammatory and neuropathic pain induced with complete Freund’s adjuvant (CFA) and chronic constrictive injury (CCI), respectively. We also evaluated the effects of the toxins on capsaicin-induced Ca²⁺ influx in dorsal root ganglion (DRG) neurons obtained from rats exposed to both models of pain. A single intrathecal injection of Phα1β reversibly inhibits CFA and CCI-induced mechanical hyperalgesia longer than a single injection of ω-conotoxin MVIIA. Phα1β and MVIIA also inhibited capsaicin-induced Ca²⁺ influx in DRG neurons. The inhibitory effect of Phα1β on capsaicin-induced calcium transients in DRG neurons was greater in the CFA model of pain, while the inhibitory effect of ω-conotoxin MVIIA was greater in the CCI model. The management of chronic inflammatory and neuropathic pain is still a major challenge for clinicians. Phα1β, a reversible inhibitor of VSCCs with a preference for N-type Ca²⁺ channels, has potential as a novel therapeutic agent for inflammatory and neuropathic pain. Clinical studies are necessary to establish the role of Phα1β in the treatment of chronic pain.     

The melatonin action on stromal stem cells within pericryptal area in colon cancer model under constant light

Constant light (LL) is associated with high incidence of colon cancer. MLT supplementation was related to the significant control of preneoplastic patterns. We sought to analyze preneoplastic patterns in colon tissue from animals exposed to LL environment (14 days; 300 lx), MLT-supplementation (10 mg/kg/day) and DMH-treatment (1,2 dimethylhydrazine; 125 mg/kg). Rodents were sacrificed and MLT serum levels were measured by radioimmunoassay. Our results indicated that LL induced ACF development (p < 0.001) with a great potential to increase the number of CD133(+) and CD68(+) cells (p < 0.05 and p < 0.001). LL also increased the proliferative process (PCNA-Li; p < 0.001) as well as decreased caspase-3 protein (p < 0.001), related to higher COX-2 protein expression (p < 0.001) within pericryptal colonic stroma (PCCS). However, MLT-supplementation controlled the development of dysplastic ACF (p < 0.001) diminishing preneoplastic patterns into PCCS as CD133 and CD68 (p < 0.05 and p < 0.001). These events were relative to decreased PCNA-Li index and higher expression of caspase-3 protein. Thus, MLT showed a great potential to control the preneoplastic patterns induced by LL.     

Bicistronic DNA Vaccines Simultaneously Encoding HIV,HSV and HPV Antigens Promote CD8+ T Cell Responses and Protective Immunity

Millions of people worldwide are currently infected with human papillomavirus (HPV), herpes simplex virus (HSV) or human immunodeficiency virus (HIV). For this enormous contingent of people, the search for preventive and therapeutic immunological approaches represents a hope for the eradication of latent infection and/or virus-associated cancer. To date, attempts to develop vaccines against these viruses have been mainly based on a monovalent concept, in which one or more antigens of a virus are incorporated into a vaccine formulation. In the present report, we designed and tested an immunization strategy based on DNA vaccines that simultaneously encode antigens for HIV, HSV and HPV. With this purpose in mind, we tested two bicistronic DNA vaccines (pIRES I and pIRES II) that encode the HPV-16 oncoprotein E7 and the HIV protein p24 both genetically fused to the HSV-1 gD envelope protein. Mice i.m. immunized with the DNA vaccines mounted antigen-specific CD8⁺ T cell responses, including in vivo cytotoxic responses, against the three antigens. Under experimental conditions, the vaccines conferred protective immunity against challenges with a vaccinia virus expressing the HIV-derived protein Gag, an HSV-1 virus strain and implantation of tumor cells expressing the HPV-16 oncoproteins. Altogether, our results show that the concept of a trivalent HIV, HSV, and HPV vaccine capable to induce CD8⁺ T cell-dependent responses is feasible and may aid in the development of preventive and/or therapeutic approaches for the control of diseases associated with these viruses.     

Testis-mediated gene transfer in mice: comparison of transfection reagents regarding transgene transmission and testicular damage

Testis-mediated gene transfer (TMGT) has been used as in vivo gene transfer technology to introduce foreign DNA directly into testes, allowing mass gene transfer to offspring via mating. In this study, we used plasmid DNA (pEGFP-N1) mixed with dimethylsulfoxide (DMSO), N,N-dimethylacetamide (DMA) or liposome (Lipofectin) in an attempt to improve TMGT. Males receiving consecutive DNA complex injections were mated to normal females to obtain F0 progeny. In vivo evaluation of EGFP expression, RT-PCR and PCR were used to detect the expression and the presence of exogenous DNA in the progeny. We also evaluated possible testicular damage by histological procedures. PC R and RT-PCR analyses revealed that liposome and DMSO increased the rate of TMGT. Histological analyses demonstrated that repeated (4 times) injections of DNA complexes can affect spermatogenesis. DMSO was the most deleterious among the reagents tested. In this study, we detected the presence of transgene in the progeny, and its expression in blood cells. Consecutive injections of DNA complexes were associated with impaired spermatogenesis, suggesting requirement of optimal conditions for DNA delivery through TMGT.     

Complete genome sequence of Corynebacterium pseudotuberculosis strain CIP 52.97, isolated from a horse in Kenya

In this work, we report the whole-genome sequence of Corynebacterium pseudotuberculosis bv. equi strain CIP 52.97 (Collection Institut Pasteur), isolated in 1952 from a case of ulcerative lymphangitis in a Kenyan horse, which has evidently caused significant losses to agribusiness. Therefore, obtaining this genome will allow the detection of important targets for postgenomic studies, with the aim of minimizing problems caused by this microorganism.     

NanoSMGT: transgene transmission into bovine embryos using halloysite clay nanotubes or nanopolymer to improve transfection efficiency

The objectives were to investigate whether: 1) nanotransfectants are more effective than other common transfection methods for SMGT; 2) NanoSMGT is able to transmit exogenous DNA molecules to bovine embryos; and 3) halloysite clay nanotubes (HCNs) can be used as a transfection reagent to improve transgene transmission. Four transfection systems were used: naked DNA (without transfectant), lipofection, nanopolymer, and halloysite clay nanotubes. Plasmid uptake by sperm and its transfer to embryos were quantified by conventional and real-time PCR, as well as EGFP expression by florescence microscopy. Furthermore, sperm motility and viability, and embryo development were investigated. Mean number of plasmids taken up was affected (P < 0.05) by transfection procedure, with the nanopolymer being the most effective transfectant (∼153 plasmids per spermatozoon). None of the treatments affected sperm motility or viability. The mean number of plasmids transmitted to four-cell stage embryos was higher (P < 0.05) in nanopolymer and HCNs than liposomes and naked DNA groups. The number of embryos carrying the transgene increased from 8–10% using naked DNA or liposomes to 40–45% using nanopolymer or HCN as transfectants (P < 0.05). There were no significant differences among transfection procedures regarding blastocyst formation rate of resulting embryos. However, no EGFP-expressing embryo was identified in any treatment. Therefore, nanotransfectants improved transgene transmission in bovine embryos without deleterious effects on embryo development. To our knowledge, this was the first time that bovine embryos carrying a transgene were produced by NanoSMGT.     

Bioturbating space enhances the effects of non‐additive interactions among benthic ecosystem engineers on cross‐habitat nutrient regeneration

Understanding the mechanisms that drive complementary interactions among species is key to the progress of the debate over the role of biodiversity in ecosystem functioning. In addition, interspecific interactions among physical ecosystem engineers have rarely been framed in the context of biodiversity experiments. Here, we provide an empirical test of how the physical niche space of species influences the effects of the biodiversity of bioturbators on cross‐habitat nutrient fluxes in benthic sediments. In the laboratory, we orthogonally manipulated the number and composition of three benthic invertebrate bioturbator species that differ in the dimensions of their bioturbating space niche; i.e. their vertical distribution in the sediment over a gradient of sediment depth and volume. The ammonium (NH₄‐N) flux from the sediment to the water was positively related to bioturbator species richness only in the sediments with the deepest depth and greatest volume. The non‐additive effects of bioturbator species richness on the benthic–pelagic NH₄‐N flux increased linearly with sediment depth and volume, but only in the three‐species mixtures. Furthermore, no individual species dominated the rates of H₄‐N fluxes, indicating that biodiversity effects were mainly driven by complementarity. These results suggest that sediment bioturbating space mediates the magnitude of non‐additive effects among the three invertebrate species and sheds light on the importance of physical niche space in modulating the positive effects of biodiversity on ecosystem functioning.     

Testing and estimating the non-disjunction fraction in Meiosis I using reference priors

In this paper we analyze the fraction of non-disjunction in Meiosis I assuming reference (non-informative) priors. We consider Jeffreys's approach to built a non-informative prior (Jeffreys's prior) for the fraction of non-disjunction in Meiosis I. We prove that Jeffreys's prior is a proper distribution. We perform Monte Carlo studies in order to compare Bayes estimates obtained assuming Jeffreys's and uniform priors. We consider full Bayesian significance test (FBST) and Bayes factor (BF) for testing precise hypothesis on the fraction of non-disjunction in Meiosis I. The ultimate goal of this paper is to compare these two test procedures through simulation studies using both prior specifications. An application to Down Syndrome data is also presented.