Structural insights into leishmanolysins encoded on chromosome 10 of Leishmania (Viannia) braziliensis

BACKGROUND Leishmanolysins have been described as important parasite virulence factors because of their roles in the infection of promastigotes and resistance to host's defenses. Leishmania (Viannia) braziliensis contains several leishmanolysin genes in its genome, especially in chromosome 10. However, the functional impact of such diversity is not understood, but may be attributed partially to the lack of structural data for proteins from this parasite. OBJECTIVES This works aims to compare leishmanolysin sequences from L. (V.) braziliensis and to understand how the diversity impacts in their structural and dynamic features. METHODS Leishmanolysin sequences were retrieved from GeneDB. Subsequently, 3D models were built using comparative modeling methods and their dynamical behavior was studied using molecular dynamic simulations. FINDINGS We identified three subgroups of leishmanolysins according to sequence variations. These differences directly affect the electrostatic properties of leishmanolysins and the geometry of their active sites. We identified two levels of structural heterogeneity that might be related to the ability of promastigotes to interact with a broad range of substrates. MAIN CONCLUSION Altogether, the structural plasticity of leishmanolysins may constitute an important evolutionary adaptation rarely explored when considering the virulence of L. (V.) braziliensis parasites.

Enterotoxigenic and non-enterotoxigenic Bacteroides fragilis from fecal microbiota of children

Enterotoxigenic Bacteroides fragilis (ETBF) is an important part of the human and animal intestinal microbiota and is commonly associated with diarrhea. ETBF strains produce an enterotoxin encoded by the bft gene located in the B. fragilis pathogenicity island (BfPAI). Non-enterotoxigenic B. fragilis (NTBF) strains lack the BfPAI and usually show two different genetic patterns, II and III, based on the absence or presence of a BfPAI-flanking region, respectively. The incidence of ETBF and NTBF strains in fecal samples isolated from children without acute diarrhea or any other intestinal disorders was determined. All 84 fecal samples evaluated were B. fragilis-positive by PCR, four of them harbored the bft gene, 27 contained the NTBF pattern III DNA sequence, and 52 were considered to be NTBF pattern II samples. One sample was positive for both ETBF and NTBF pattern III DNA sequences. All 19 B. fragilis strains isolated by the culture method were bft-negative, 9 belonged to pattern III and 10 to pattern II. We present an updated overview of the ETBF and NTBF incidence in the fecal microbiota of children from Sao Paulo City, Brazil.

Biological and molecular characteristics of zymv isolates from cucumber [cucumis sativus] plant grown in Riyadh, KSA

Zucchini yellow mosaic virus[ZYMV] is potyvirus with a worldwide distribution. The virus is the most prevalent in cucurbits. Samples of cucumber plants [Cucumls sativus L.] that show symptoms of virus infection were collected during the 18-May-2009 growing season from field-grown cucumber in Riyadh Saudi Arabia. Based on DAS-ELISA with a polyclonal antiserum against ZYMV and reverse transcription polymerase chain reaction [RT-PCR] analysis using two primer pairs, the potyvirus was identified as strain of ZYMV. The anti-ZYMV antibodies in dot-blot, confirming the identity of the isolated viral particles as a potyvirus immunogenically related to ZYMV. Nucleotides Sequence analysis confirms that the isolated virus belong to potyvirus and its gen bank is GU808330.1. This is the first report on ZYMV as causal virus infecting cucumber in KSA

Prenatal Diagnosis of Restrictive Dermopathy.

We report three cases of Restrictive dermopathy from unrelated families. All were small for gestational age with small eyes and open mouth. Taut, stretched skin caused restriction of movements. Clavicular hypoplasia was a consistent radiological feature. Molecular diagnosis in the parents facilitated prenatal diagnosis from chorionic villous sample (CVS) in the subsequent pregnancy.

High expression of human carboxypeptidase M in Pichia pastoris: Purification and partial characterization

Carboxypeptidase M (CPM) is an extracellular glycosylphosphatidyl-inositol-anchored membrane glycoprotein, which removes the C-terminal basic residues, lysine and arginine, from peptides and proteins at neutral pH. CPM plays an important role in the control of peptide hormones and growth factor activity on the cell surface. The present study was carried out to clone and express human CPM in the yeast Pichia pastoris in order to evaluate the importance of this enzyme in physiological and pathological processes. The cDNA for the enzyme was amplified from total placental RNA by RT-PCR and cloned in the vector pPIC9, which uses the methanol oxidase promoter and drives the expression of high levels of heterologous proteins in P. pastoris. The cpm gene, after cloning and transfection, was integrated into the yeast genome, which produced the active protein. The recombinant protein was secreted into the medium and the enzymatic activity was measured using the fluorescent substrate dansyl-Ala-Arg. The enzyme was purified by a two-step protocol including gel filtration and ion-exchange chromatography, resulting in a 1753-fold purified active protein (16474 RFU mg protein-1 min-1). This purification protocol permitted us to obtain 410 mg of the purified protein per liter of fermentation medium. SDS-PAGE showed that recombinant CPM migrated as a single band with a molecular mass similar to that of native placental enzyme (62 kDa), suggesting that the expression of a glycosylated protein had occurred. These results demonstrate for the first time the establishment of a method using P. pastoris to express human CPM necessary to the development of specific antibodies and antagonists, and the analysis of the involvement of this peptidase in different physiological and pathological processes.

Análisis de expresión global del cáncer cérvico uterino: rutas metabólicas y genes alterados / Global expression analysis in uterine cervical cancer: Metabolic pathways and altered genes

High risk human papillomavirus (HPV) infection is considered to be the most important etiological factor of Cervical Uterine Cancer. In order to determine the global expression pattern and to identify possible molecular markers of cervical cancer, cDNA arrays with probe sets complementary to 8,000 human genes were used to examine the expression profiles among 5 cell lines derived from human cervical cancer, three HPV16(+) tumor samples and three normal cervical tissues HPV(-). The levels of expression of different cellular processes were identified. Hierarchical clustering was performed and the gene expression using RT-PCR was confirmed. Two genes were found to be consistently overexpressed in invasive cervical cancer biopsies; one of them, IL-6 was previously reported to be overexpressed in cervical cancer and one novel gene, MMP10, previously not known to be related to cervical cancer. Hierarchical clustering of the expression data revealed that samples with common HPV type infection grouped together, maybe this could mean that differences between HPV types could be indirectly determined by expression profiles.

La infección por virus de papiloma de alto riesgo (VPH) es considerada como el factor etiológico más importante del cáncer cérvico uterino (CaCU). Con el fin de determinar el patrón de expresión global e identificar algunos posibles genes marcadores del CaCU, se utilizaron microhileras de DNA que contenían 8,000 secuencias que codificaban para transcritos diferentes, para estudiar los perfiles de expresión de cinco líneas celulares derivadas de CaCU, tres muestras tumorales conteniendo VPH 16 y tres muestras normales negativas para la presencia de VPH. Se identificaron los niveles de expresión de genes relacionados con diferentes rutas metabólicas. Se llevó a cabo el análisis de agrupamiento jerárquico y posteriormente se confirmó la sobrexpresión de dos genes mediante RT-PCR. Estos dos genes se encontraron sobrexpresados en biopsias tumorales cervicales. Uno de ellos, el gen de IL6, que ha sido previamente reportado en relación con CaCU, así como el gen de la matriz-metaloproteasa 10 (MMP10) por primera vez relacionado con esta neoplasia. El análisis de agrupamiento jerárquico, además, reveló que las muestras que contienen el mismo tipo viral están asociadas, sugiriendo posibles diferencias en expresión entre tipos virales.

Virulence factors of non-O1 non-O139 Vibrio cholerae isolated in Córdoba, Argentina / Factores de virulencia de Vibrio cholerae no-O1 no-O139 aislados en Córdoba, Argentina

V. cholerae non-O1 non-O139 serogroups isolated from clinical and environmental sources in Córdoba, Argentina, were analyzed for the presence and expression of virulence genes. Most of the strains studied contained the genes toxR and hlyA, but lacked ctxA, zot, ace, tcpA and stn. The culture supernatants were tested for hemolytic and cytotoxic activity. The enterotoxic potential of the strains was studied in a rabbit ileal loop assay and their genetic profiles were compared by PFGE. The environmental strains varied in their virulence phenotype and showed no-clonal relationships. The clinical strains were highly enterotoxic, hemolytic, proteolytic and showed indistinguishable PFGE profiles, although they differed in their cytotoxic activity. This is the first description, using cell culture and “in vivo” studies, of the virulence properties of non-O1 non-O139 V. cholerae from Argentina.

En este trabajo se analizó la presencia y expresión de genes de virulencia en V. cholerae no-O1 no-O139 de origen clínico y ambiental, aislados en Córdoba, Argentina. La mayoría de las cepas estudiadas contiene los genes toxR y hlyA, pero no ctxA, zot, ace, tcpA y stn. Se analizó la actividad hemolítica y citotóxica de estas cepas en los sobrenadantes de cultivo, así como su potencial enterotóxico en ensayos de asa ileal ligada de conejo. Además, los aislamientos fueron comparados por sus perfiles genéticos en PFGE. Las cepas del medio ambiente mostraron variación en su fenotipo de virulencia y no mostraron relación clonal. Las cepas clínicas fueron muy enterotóxicas, hemolíticas, proteolíticas y mostraron perfiles indistinguibles de PFGE, aunque mostraron diferencias en su actividad citotóxica. En este trabajo se describen por primera vez, utilizando ensayos de cultivo celular e “in vivo”, propiedades de virulencia de V. cholerae no-O1 no-O139 aislados en Argentina.

Thrombotic thrombocytopenic purpura.

A 6-year-old boy presented with microangiopathic hemolytic anemia, thrombo-cytopenia, altered sensorium and intractable bleeding. A diagnosis of thrombotic thrombocytopenic purpura was made and the child recovered dramatically after plasmapheresis. Recent developments in the understanding of TTP are reviewed, including the importance of a metaloprotease required to cleave multimers of von Willibrand factor.

Matrix metalloproteinases in human gliomas: activation of matrix metalloproteinase-2 (MMP-2) may be correlated with membrane-type-1 matrix metalloproteinase (MT1-MMP) expression

To evaluate possible roles of matrix metalloproteinase (MMP)-1, -2, tissue inhibitor of metalloproteinase (TIMP)-1, -2 and membrane-type-1 matrix metalloproteinase (MT1-MMP) in invasion of human gliomas, expressions of these proteins were investigated in ten cases of human glioma and two meningioma tissues and eight human glioma cell lines. In gelatin zymography, MMP-2 activities of glioblastomas were higher than astrocytomas. The activated form of MMP-2 was seen in five of six cases of glioblastomas, but not in astrocytomas. MMP-9 activity was detected in all cases of malignant astrocytomas but the reactivity of MMP-9 was weaker than that of MMP-2. MT1-MMP mRNA expression in glioblastomas was higher than that in astrocytomas. Five cases of glioblastomas with activated form of MMP-2 had MT1-MMP expressions. In vitro, human glioma cell lines with high expression of MT1-MMP also showed high MMP-2 activity. TIMP-1 transcripts were constitutively present in almost all glioma tissues and cell lines, whereas TIMP-2 mRNA were weak especially in malignant gliomas. Imbalance of TIMP-2/MMP-2 was observed using immunoprecipitation analysis in a glioma cell line. High expression of MMP-2 and MT1-MMP is possibly involved in invasiveness of malignant glioma.

Matrix metalloproteinases in human gliomas: activation of matrix metalloproteinase-2 (MMP-2) may be correlated with membrane-type-1 matrix metalloproteinase (MT1-MMP) expression

To evaluate possible roles of matrix metalloproteinase (MMP)-1, -2, tissue inhibitor of metalloproteinase (TIMP)-1, -2 and membrane-type-1 matrix metalloproteinase (MT1-MMP) in invasion of human gliomas, expressions of these proteins were investigated in ten cases of human glioma and two meningioma tissues and eight human glioma cell lines. In gelatin zymography, MMP-2 activities of glioblastomas were higher than astrocytomas. The activated form of MMP-2 was seen in five of six cases of glioblastomas, but not in astrocytomas. MMP-9 activity was detected in all cases of malignant astrocytomas but the reactivity of MMP-9 was weaker than that of MMP-2. MT1-MMP mRNA expression in glioblastomas was higher than that in astrocytomas. Five cases of glioblastomas with activated form of MMP-2 had MT1-MMP expressions. In vitro, human glioma cell lines with high expression of MT1-MMP also showed high MMP-2 activity. TIMP-1 transcripts were constitutively present in almost all glioma tissues and cell lines, whereas TIMP-2 mRNA were weak especially in malignant gliomas. Imbalance of TIMP-2/MMP-2 was observed using immunoprecipitation analysis in a glioma cell line. High expression of MMP-2 and MT1-MMP is possibly involved in invasiveness of malignant glioma.

Role of tissue inhibitors of metalloproteinases (TIMPs) in colorectal carcinoma

Increased production of matrix metalloproteinases (MMPs) has been associated with increases in invasive and metastatic potential in many types of human carcinoma. Tissue inhibitors of metalloproteinase (TIMP)-1 inhibits most interstitial collagenases and MMP-9. TIMP-2 binds specifically and noncovalently to the pro-form of MMP-2 and inhibits its enzyme activity. In this study, we examined TIMP-1 and TIMP-2 expressions in relation to clinicopathological variables in colorectal carcinoma with in situ hybridization and immunohistochemistry. TIMP-1 and TIMP-2 expressions were localized overwhelmingly to pericancer stromal cells, while malignant and normal mucosal cells were weak or negative. Strong stromal TIMP-1 immunoreactivity correlated with Dukes' stage (p=0.022), status of lymph node metastasis (p=0.044) and poor survival (p= 0.005). The degree of immunohistochemical staining of TIMP-2 did not correlate with all clinicopathological variables. The correlation between enhanced TIMP-1 expression and advanced stage and poor survival suggest a growth promoting activity of TIMP-1 in colorectal carcinoma.