Anopheles species composition explains differences in Plasmodium transmission in La Guajira, northern Colombia

Malaria in La Guajira, the most northern state of Colombia, shows two different epidemiological patterns. Malaria is endemic in the municipality of Dibulla whereas in Riohacha it is characterised by sporadic outbreaks. This study aimed to establish whether differences in transmission patterns could be attributed to different vector species. The most abundant adult female species were Anopheles aquasalis, exclusive to Riohacha, and Anopheles darlingi, restricted to Dibulla. Anopheles mosquitoes were identified using morphology and the molecular markers internal transcribed spacer 2 and cytochrome c oxidase I. All specimens (n = 1,393) were tested by ELISA to determine natural infection rates with Plasmodium falciparum and Plasmodium vivax. An. darlingi was positive for P. vivax 210, with an infection rate of 0.355% and an entomological inoculation rate of 15.87 infective bites/person/year. Anopheles albimanus larvae were the most common species in Riohacha, found in temporary swamps; in contrast, in Dibulla An. darlingi were detected mainly in permanent streams. Distinctive species composition and larval habitats in each municipality may explain the differences in Plasmodium transmission and suggest different local strategies should be used for vector control.

Ritchie [Josia George] [et] Hunter [Alfred C.] Cannes, 21-1-20 [tournoi de lawn-tennis du Carlton de Cannes] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 57738

Estimation of surface roughness in a semiarid region from C-band ERS-1 synthetic aperture radar data

In this study, we investigated the feasibility of using the C-band European Remote Sensing Satellite (ERS-1) synthetic aperture radar (SAR) data to estimate surface soil roughness in a semiarid rangeland. Radar backscattering coefficients were extracted from a dry and a wet season SAR image and were compared with 47 in situ soil roughness measurements obtained in the rocky soils of the Walnut Gulch Experimental Watershed, southeastern Arizona, USA. Both the dry and the wet season SAR data showed exponential relationships with root mean square (RMS) height measurements. The dry C-band ERS-1 SAR data were strongly correlated (R² = 0.80), while the wet season SAR data have somewhat higher secondary variation (R² = 0.59). This lower correlation was probably provoked by the stronger influence of soil moisture, which may not be negligible in the wet season SAR data. We concluded that the single configuration C-band SAR data is useful to estimate surface roughness of rocky soils in a semiarid rangeland.

T cell receptor beta chain gene rearrangements and V beta gene usage in horse cytochrome c-specific T cell hybridomas.

Comparison of T cell receptor alpha and beta-chain genes in murine major histocompatibility complex (MHC) class I and class II-restricted T cell clones and hybridomas recognizing different antigens indicates that no simple correlation exists between the observed antigen/MHC specificity and the expression of certain alpha and beta-chain heterodimers. We have attempted to establish a possible correlation by analyzing T cell receptor beta chain gene rearrangements and V beta gene usage in five T cell hybridomas with identical antigen/MHC specificity and another hybridoma recognizing a different antigenic determinant in association with the same restriction molecule. We report here that in each of the five clones a uniquely rearranged beta chain gene is expressed in combination with at least two different V beta gene segments. The presence of the differently rearranged T cell receptor beta chain genes correlated with the finding of distinct fine specificity pattern of antigen recognition in each of the hybridomas. Interestingly, two hybridomas specific for different epitopes showed identical beta chain D-J rearrangements indicating that the differences might be encoded by the alpha chain gene or/and the V beta gene element.

The novel ss469415590 variant predicts virological response to therapy in patients with chronic hepatitis C virus type 1 infection.

BACKGROUND: A novel dinucleotide variant TT/W10;G (ss469415590) has been associated with hepatitis C virus clearance. AIM: To assess the role of the ss469415590 variant, compared with the known IL28B polymorphisms (rs8099917, rs12979860 and rs12980275) for predicting virological response to therapy in chronic hepatitis C, and its association with the CXCL10 chemokine serum levels - a surrogate marker of interferon-stimulated genes activation. METHODS: Multivariate analysis of factors predicting rapid and sustained virological response in 280 consecutive, treatment-naïve, nondiabetic, Caucasian patients with chronic hepatitis C treated with peginterferon alpha and ribavirin. RESULTS: In hepatitis C virus genotype 1, the OR (95% CI) for rapid and sustained virological response for the wild-type ss469415590 TT was 9.88 (1.99-48.99) and 7.25 (1.91-27.51), respectively, similar to those found for rs12979860 CC [9.55 (1.93-47.37) and 6.30 (1.71-23.13)] and for rs12980275 AA [9.62 (1.94-47.77] and 7.83 (2.02-30.34)], but higher than for rs8099917 TT [4.8 (1.73-13.33) and 4.75 (2.05-10.98)]. In hepatitis C virus genotype 1, mean (SD) CXCL10 levels in patients with the TT/TT, TT/W10;G and W10;G/W10;G variants were, respectively, 355.1 (240.6), 434.4 (247.4) and 569.9 (333.3) (P = 0.04). In patients with genotypes 2 and 3 no significant association was found for TT/W10;G with viral response. The predictive value of ss469415590 was stronger in patients with advanced fibrosis. CONCLUSIONS: The novel IL28B variants at marker ss469415590 predict response to IFN alpha in chronic hepatitis C patients, especially in those with advanced fibrosis. Their determination may be superior to that of known IL28B variants for patient management using IFN-based regimens.

Different antigen-presenting cells differ in their capacity to induce lymphokine production and proliferation of an apo-cytochrome c-specific T cell clone.

The activation of an apo-cytochrome c-specific T cell clone was found to differ, depending on the antigen-presenting cell population. Whereas total syngeneic spleen cells and bone marrow macrophages could be shown to trigger proliferation, IL 2, and MAF production by the T cell clone, a B cell lymphoma only induced MAF secretion. Further studies demonstrated that this effect was not due to a different antigen processing by the B lymphoma or to limiting amounts of Ia and antigen molecules on the B lymphoma cell surface. The dissociation of induction of MAF production from IL-2 production/proliferation found with the different antigen-presenting cells indicates strongly that molecules other than Ia and antigen may be required for the complete functional activation of antigen-specific T cell clones.

T-cell hybridoma specific for a cytochrome c peptide: specific antigen binding and interleukin 2 production.

T-cell hybridomas were obtained after fusion of BW 5147 thymoma and long-term cultured T cells specific for cytochrome c peptide 66-80 derivatized with a 2,4-dinitroaminophenyl (DNAP) group. The resulting hybridomas were selected for their capacity to specifically bind to soluble radiolabeled peptide antigen. One T-cell hybrid was positive for antigen binding. This hybrid T cell exhibits surface phenotypic markers of the parent antigen-specific T cells. The binding could be inhibited either by an excess of unlabeled homologous antigen or by cytochrome c peptide 11-25 derivatized with a 2-nitrophenylsulfenyl group. Several other peptide antigens tested failed to inhibit binding of the radioactive peptide. This suggests that a specific amino acid sequence, modified by a DNAP group, is the antigenic structure recognized by the putative T-cell receptor. In addition, direct interaction of DNAP-66-80 peptide with the hybridoma cell line induced production of the T-cell growth factor interleukin 2. Furthermore, supernatants derived from syngeneic macrophages pulsed with the relevant peptide also induced the antigen-specific hybridoma to produce interleukin 2.

The redox state of cytochrome C modulates resistance to methotrexate in human MCF7 breast cancer cells

Background: Methotrexate is a chemotherapeutic agent used to treat a variety of cancers. However, the occurrence of resistance limits its effectiveness. Cytochrome c in its reduced state is less capable of triggering the apoptotic cascade. Thus, we set up to study the relationship among redox state of cytochrome c, apoptosis and the development of resistance to methotrexate in MCF7 human breast cancer cells. Results: Cell incubation with cytochrome c-reducing agents, such as tetramethylphenylenediamine, ascorbate or reduced glutathione, decreased the mortality and apoptosis triggered by methotrexate. Conversely, depletion of glutathione increased the apoptotic action of methotrexate, showing an involvement of cytochrome c redox state in methotrexateinduced apoptosis. Methotrexate-resistant MCF7 cells showed increased levels of endogenous reduced glutathione and a higher capability to reduce exogenous cytochrome c. Using functional genomics we detected the overexpression of GSTM1 and GSTM4 in methotrexate-resistant MCF7 breast cancer cells, and determined that methotrexate was susceptible of glutathionylation by GSTs. The inhibition of these GSTM isoforms caused an increase in methotrexate cytotoxicity in sensitive and resistant cells. Conclusions: We conclude that overexpression of specific GSTMs, GSTM1 and GSTM4, together with increased endogenous reduced glutathione levels help to maintain a more reduced state of cytochrome c which, in turn, would decrease apoptosis, thus contributing to methotrexate resistance in human MCF7 breast cancer cells.

Impact of soluble CD26 on treatment outcome and hepatitis C virus-specific T cells in chronic hepatitis C virus genotype 1 infection.

BACKGROUND: Interferon and ribavirin therapy for chronic hepatitis C virus (HCV) infection yields sustained virological response (SVR) rates of 50-80%. Several factors such as non-1 genotype, beneficial IL28B genetic variants, low baseline IP-10, and the functionality of HCV-specific T cells predict SVR. With the pending introduction of new therapies for HCV entailing very rapid clearance of plasma HCV RNA, the importance of baseline biomarkers likely will increase in order to tailor therapy. CD26 (DPPIV) truncates the chemokine IP-10 into a shorter antagonistic form, and this truncation of IP-10 has been suggested to influence treatment outcome in patients with chronic HCV infection patients. In addition, previous reports have shown CD26 to be a co-stimulator for T cells. The aim of the present study was to assess the utility of CD26 as a biomarker for treatment outcome in chronic hepatitis C and to define its association with HCV-specific T cells. METHODS: Baseline plasma from 153 genotype 1 and 58 genotype 2/3 infected patients enrolled in an international multicenter phase III trial (DITTO-HCV) and 36 genotype 1 infected patients participating in a Swedish trial (TTG1) were evaluated regarding baseline soluble CD26 (sCD26) and the functionality of HCV-specific CD8(+) T cells. RESULTS: Genotype 1 infected patients achieving SVR in the DITTO (P = 0.002) and the TTG1 (P = 0.02) studies had lower pretreatment sCD26 concentrations compared with non-SVR patients. Sixty-five percent of patients with sCD26 concentrations below 600 ng/mL achieved SVR compared with 39% of the patients with sCD26 exceeding 600 ng/mL (P = 0.01). Patients with sCD26 concentrations below 600 ng/mL had significantly higher frequencies of HCV-specific CD8(+) T cells (P = 0.02). CONCLUSIONS: Low baseline systemic concentrations of sCD26 predict favorable treatment outcome in chronic HCV infection and may be associated with higher blood counts of HCV-specific CD8(+) T cells.

Preclinical evaluation of the immunogenicity of C-type HIV-1-based DNA and NYVAC vaccines in the Balb/C mouse model.

As part of a European initiative (EuroVacc), we report the design, construction, and immunogenicity of two HIV-1 vaccine candidates based on a clade C virus strain (CN54) representing the current major epidemic in Asia and parts of Africa. Open reading frames encoding an artificial 160-kDa GagPolNef (GPN) polyprotein and the external glycoprotein gp120 were fully RNA and codon optimized. A DNA vaccine (DNA-GPN and DNA-gp120, referred to as DNA-C), and a replication-deficient vaccinia virus encoding both reading frames (NYVAC-C), were assessed regarding immunogenicity in Balb/C mice. The intramuscular administration of both plasmid DNA constructs, followed by two booster DNA immunizations, induced substantial T-cell responses against both antigens as well as Env-specific antibodies. Whereas low doses of NYVAC-C failed to induce specific CTL or antibodies, high doses generated cellular as well as humoral immune responses, but these did not reach the levels seen following DNA vaccination. The most potent immune responses were detectable using prime:boost protocols, regardless of whether DNA-C or NYVAC-C was used as the priming or boosting agent. These preclinical findings revealed the immunogenic response triggered by DNA-C and its enhancement by combining it with NYVAC-C, thus complementing the macaque preclinical and human phase I clinical studies of EuroVacc.

Bartonella apis sp. nov., a honey bee gut symbiont of the class Alphaproteobacteria.

Here, we report the culture and characterization of an alphaproteobacterium of the order Rhizobiales, isolated from the gut of the honey bee Apis mellifera. Strain PEB0122T shares >95̴1;% 16S rRNA gene sequence similarity with species of the genus Bartonella, a group of mammalian pathogens transmitted by bloodsucking arthropods. Phylogenetic analyses showed that PEB0122T and related strains from the honey bee gut form a sister clade of the genus Bartonella. Optimal growth of strain PEB0122T was obtained on solid media supplemented with defibrinated sheep blood under microaerophilic conditions at 35-37̴1;°C, which is consistent with the cultural characteristics of other species of the genus Bartonella. Reduced growth of strain PEB0122T also occurred under aerobic conditions. The rod-shaped cells of strain PEB0122T had a mean length of 1.2-1.8̴1;μm and revealed hairy surface structures. Strain PEB0122T was positive for catalase, cytochrome c oxidase, urease and nitrate reductase. The fatty acid composition was comparable to those of other species of the genus Bartonella, with palmitic acid (C16̴1;:̴1;0) and isomers of 18- and 19-carbon chains being the most abundant. The genomic DNA G+C content of PEB0122T was determined to be about 45.5 mol%. The high 16S rRNA gene sequence similarity with species of Bartonella and its close phylogenetic position suggest that strain PEB0122T represents a novel species within the genus Bartonella, for which we propose the name Bartonella apis sp. nov. The type strain is PEB0122T (̴1;=̴1;NCIMB 14961T̴1;=̴1;DSM 29779T).

Assessment of the degree of contamination of rat germ cell preparations using specific cDNA probes

Recent reports showing a decrease in sperm count in men have brought new concerns about male infertility. Animal models have been widely used to provide some relevant information about the human male gamete, and extrapolations are made to men and to the clinical context. The present study assesses one of the methods used for separation of germ cells of the adult rat testis, namely centrifugal elutriation followed by density gradients (Percoll®). This method was chosen since it presents the best results for cell purity in separating germ cells from the rat testis. A comparison between continuous and discontinuous Percoll® gradients was performed in order to identify the best type of gradient to separate the cells. Maximal cell purity was obtained for spermatocytes (81 ± 8.2%, mean ± SEM) and spermatids (84 ± 2.6%) using centrifugal elutriation followed by continuous Percoll® gradients. A significant difference in purity was observed between elongating spermatids harvested from continuous Percoll® gradients and from discontinuous gradients. Molecular analysis was used to assess cell contamination by employing specific probes, namely transition protein 2 (TP2), mitochondrial cytochrome C oxidase II (COX II), and sulfated glycoprotein 1 (SGP1). Molecular analysis of the samples demonstrated that morphological criteria are efficient in characterizing the main composition of the cell suspension, but are not reliable for identifying minimal contamination from other cells. Reliable cell purity data should be established using molecular analysis