Development of a duplex real-time PCR for the detection of Rickettsia spp. and typhus group rickettsia in clinical samples.

Molecular diagnosis using real-time polymerase chain reaction (PCR) may allow earlier diagnosis of rickettsiosis. We developed a duplex real-time PCR that amplifies (1) DNA of any rickettsial species and (2) DNA of both typhus group rickettsia, that is, Rickettsia prowazekii and Rickettsia typhi. Primers and probes were selected to amplify a segment of the 16S rRNA gene of Rickettsia spp. for the pan-rickettsial PCR and the citrate synthase gene (gltA) for the typhus group rickettsia PCR. Analytical sensitivity was 10 copies of control plasmid DNA per reaction. No cross-amplification was observed when testing human DNA and 22 pathogens or skin commensals. Real-time PCR was applied to 16 clinical samples. Rickettsial DNA was detected in the skin biopsies of three patients. In one patient with severe murine typhus, the typhus group PCR was positive in a skin biopsy from a petechial lesion and seroconversion was later documented. The two other patients with negative typhus group PCR suffered from Mediterranean and African spotted fever, respectively; in both cases, skin biopsy was performed on the eschar. Our duplex real-time PCR showed a good analytical sensitivity and specificity, allowing early diagnosis of rickettsiosis among three patients, and recognition of typhus in one of them.

Three-step pathway engineering results in more incidence rate and higher emission of nerolidol and improved attraction of Diadegma semiclausum

The concentration and ratio of terpenoids in the headspace volatile blend of plants have a fundamental role in the communication of plants and insects. The sesquiterpene (E)-nerolidol is one of the important volatiles with effect on beneficial carnivores for biologic pest management in the field. To optimize de novo biosynthesis and reliable and uniform emission of (E)-nerolidol, we engineered different steps of the (E)-nerolidol biosynthesis pathway in Arabidopsis thaliana. Introduction of a mitochondrial nerolidol synthase gene mediates de novo emission of (E)-nerolidol and linalool. Co-expression of the mitochondrial FPS1 and cytosolic HMGR1 increased the number of emitting transgenic plants (incidence rate) and the emission rate of both volatiles. No association between the emission rate of transgenic volatiles and their growth inhibitory effect could be established. (E)-Nerolidol was to a large extent metabolized to non-volatile conjugates.

The MTR A2756G polymorphism is associated with an increase of plasma homocysteine concentration in Brazilian individuals with Down syndrome

Individuals with Down syndrome (DS) present decreased homocysteine (Hcy) concentration, reflecting a functional folate deficiency secondary to overexpression of the cystathionine ß-synthase gene. Since plasma Hcy may be influenced by genetic polymorphisms, we evaluated the influence of C677T and A1298C polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR), of A2756G polymorphism in the methionine synthase gene (MTR), and of A80G polymorphism in the reduced folate carrier 1 gene on Hcy concentrations in Brazilian DS patients. Fifty-six individuals with free trisomy 21 were included in the study. Plasma Hcy concentrations were measured by liquid chromatography_tandem mass spectrometry with linear regression coefficient r² = 0.9996, average recovery between 92.3 to 108.3% and quantification limits of 1.0 µmol/L. Hcy concentrations >15 µmol/L were considered to characterize hyperhomocystinemia. Genotyping for the polymorphisms was carried out by polymerase chain reaction followed by enzyme digestion and allele-specific polymerase chain reaction. The mean Hcy concentration was 5.2 ± 3.3 µmol/L. There was no correlation between Hcy concentrations and age, gender or MTHFR C677T, A1298C and reduced folate carrier 1 A80G genotype. However, Hcy concentrations were significantly increased in the MTR 2756AG heterozygous genotype compared to the MTR 2756AA wild-type genotype. The present results suggest that the heterozygous genotype MTR 2756AG is associated with the increase in plasma Hcy concentrations in this group of Brazilian patients with DS.

Characterization of polyhydroxyalkanoates accumulating vibrios from marine benthic environments and production studies of polyhydroxyalkanoates by Vibrio sp. BTKB33

The present work deals with the characterization of polyhydroxyalkanoates accumulating vibrios from marine benthic environments and production studies of polyhydroxyalkanoates by vibrio sp.BTKB33. Vibrios are a group of (iram negative, curved or straight motile rods that normally inhabit the aquatic environments.The present study therefore aimed at evaluating the occurrence of PHA accumulating vibrios inhabiting marine benthic environments; characterizing the potential PHA accumulators employing phenotypic and genotypic approaches and molecular characterization of the PHA synthase gene. The study also evaluated the PHA production in V:'hri0 sp. strain BTKB33, through submerged fennentation using statistical optimization and characterized the purified biopolymer. Screening for PHA producing vibrios from marine benthic environments. Characterization of PHA producers employing phenotypic and genotypic approaches.The incidence of PHA accumulation in Vibrio sp. isolated from marine sediments was observed to be high, indicating that the natural habitat of these bacteria are stressful. Considering their ubiquitous nature, the ecological role played by vibrios in maintaining the delicate balance of the benthic ecosystem besides returning potential strains, with the ability to elaborate a plethora of extracellular enzymes for industrial application, is significant. The elaboration of several hydrolytic enzymes by individuals also emphasize the crucial role of vibrios in the mineralization process in the marine environment. This study throws light on the extracellular hydrolytic enzyme profile exhibited by vibrios. It was concluded that apart from the PHA accumulation, presence of exoenzyme production and higher MAR index also aids in their survival in the highly challenging benthic enviromnents. The phylogenetic analysis of the strains and studies on intra species variation within PHA accumulating strains reveal their diversity. The isolate selected for production in this study was Vibrio sp. strain BTKB33, identified as V.azureus by 16S rDNA sequencing and phenotypic characterization. The bioprocess variables for PHA production utilising submerged fermentation was optimized employing one-factor-at-a-time-method, PB design and RSM studies. The statistical optimization of bioprocess variables revealed that NaCl concentration, temperature and incubation period are the major bioprocess variables influencing PHA production and PHA content. The presence of Class I PHA synthase genes in BTKB33 was also unveiled. The characterization of phaC genes by PCR and of the extracted polymer employing FTIR and NMR analysis revealed the presence of polyhydroxybutyrate, smallest known PI-IAs, having wider domestic, industrial and medical application. The strain BTKB33 bearing a significant exoenzyme profile, can thus be manipulatedin future for utilization of diverse substrates as C- source for PHA production. In addition to BTKB33, several fast growing Vibrio sp. having PHA accumulating ability were also isolated, revealing the prospects of this environment as a mine for novel PHA accumulating microbes. The findings of this study will provide a reference for further research in industrial production of PHAs from marine microorganisms .

Immunohistochemical analysis of neuron types in the mouse small intestine

The definition of the nerve cell types of the myenteric plexus of the mouse small intestine has become important, as more researchers turn to the use of mice with genetic mutations to analyze roles of specific genes and their products in enteric nervous system function and to investigate animal models of disease. We have used a suite of antibodies to define neurons by their shapes, sizes, and neurochemistry in the myenteric plexus. Anti-Hu antibodies were used to reveal all nerve cells, and the major subpopulations were defined in relation to the Hu-positive neurons. Morphological Type II neurons, revealed by anti-neurofilament and anti-calcitonin gene-related peptide antibodies, represented 26% of neurons. The axons of the Type II neurons projected through the circular muscle and submucosa to the mucosa. The cell bodies were immunoreactive for choline acetyltransferase (ChAT), and their terminals were immunoreactive for vesicular acetylcholine transporter (VAChT). Nitric oxide synthase (NOS) occurred in 29% of nerve cells. Most were also immunoreactive for vasoactive intestinal peptide, but they were not tachykinin (TK)-immunoreactive, and only 10% were ChAT-immunoreactive. Numerous NOS terminals occurred in the circular muscle. We deduced that 90% of NOS neurons were inhibitory motor neurons to the muscle (26% of all neurons) and 10% (3% of all neurons) were interneurons. Calretinin immunoreactivity was found in a high proportion of neurons (52%). Many of these had TK immunoreactivity. Small calretinin neurons were identified as excitatory neurons to the longitudinal muscle (about 20% of neurons, with ChAT/calretinin/+/- TK chemical coding). Excitatory neurons to the circular muscle (about 10% of neurons) had the same coding. Calretinin immunoreactivity also occurred in a proportion of Type II neurons. Thus, over 90% of neurons in the myenteric plexus of the mouse small intestine can be currently identified by their neurochemistry and shape.

5-Lipoxygenase plays a role in the control of parasite burden and contributes to oxidative damage of erythrocytes in murine Chagas` disease

Chagas` disease is accompanied by severe anemia and oxidative stress, which may contribute to mortality. In this study, we investigated the role of 5-lipoxygenase (5-LO) in the control of parasitism and anemia associated with oxidative damage of erythrocytes in experimental Trypanosoma cruzi infection. Wild-type C57BL/6, 129Sv mice treated or not with nordihydroguaiaretic acid (NDGA, 5-LO inhibitor), mice lacking the 5-LO enzyme gene (5-LO(-/-)) and inducible nitric oxide synthase gene (iNOS(-/-)) were infected with the Y strain of T cruzi. impairment of 5-LO resulted in increased numbers of trypomastigote forms in the blood and amastigote forms in the heart of infected mice. We assessed oxidative stress in erythrocytes by measuring oxygen uptake, induction time and chemiluminescence following treatment with tert-butyl hydroperoxide (TBH). Our results show that 5-LO metabolites increased lipid peroxidation levels in erythrocytes during the early phase of murine T cruzi infection. NDGA treatment reduced oxidative damage of erythrocytes in C57BL/6 T cruzi-infected mice but not in C57BL/6 iNOS-/- infected mice, showing that the action of NDGA is dependent on endogenous nitric oxide (NO). In addition, our results show that 5-LO metabolites do not participate directly in the development of anemia in infected mice. We conclude that 5-LO products may not only play a major role in controlling heart tissue parasitism, i.e., host resistance to acute infection with T cruzi in vivo, but in the event of an infection also play an important part in erythrocyte oxidative stress, an NO-dependent effect. (C) 2009 Elsevier B.V. All rights reserved.

Sugarcane Phosphoribosyl Pyrophosphate Synthetase: Molecular Characterization of a Phosphate-independent PRS

Phosphoribosyl pyrophosphate synthetase (PRS-EC:2.7.6.1) is an important enzyme present in several metabolic pathways, thus forming a complex family of isoenzymes. However, plant PRS enzymes have not been extensively investigated. In this study, a sugarcane prs gene has been characterized from the Sugar Cane Expressed Sequence Tag Genome Project. This gene contains a 984-bp open reading frame encoding a 328-amino acid protein. The predicted amino acid sequence has 77% and 78% amino acid sequence identity to Arabidopsis thaliana and Spinacia oleracea PRS4, respectively. The assignment of sugarcane PRS as a phosphate-independent PRS isoenzyme (Class II PRS) is verified following enzyme assay and phylogenetic reconstruction of PRS homologues. To gain further insight into the structural framework of the phosphate independence of sugarcane PRS, a molecular model is described. This model reveals the formation of two conserved domains elucidating the structural features involved in sugarcane PRS phosphate independence. The recombinant PRS retains secondary structure elements and a quaternary arrangement consistent with known PRS homologues, based on circular dichroism measurements.

Caracterização funcional de fatores de transcrição hipotéticos de Neurospora crassa

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise da expressão dos genes envolvidos na via de síntese de cafeína em plantas de café (Coffea arabica) apresentando diferentes teores de cafeína

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização funcional e estrutural das proteínas RUV-1 e RUV-2 do fungo Neurospora crassa

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Brazilian spotted fever: Real-time PCR for diagnosis of fatal cases

Suspicion of Brazilian spotted fever (BSF) should occur in endemic regions upon surveillance of the acute febrile icteric hemorrhagic syndrome (AFIHS). However, limitations associated with currently available laboratory tests pose a challenge to early diagnosis, especially in fatal cases. Two real-time PCR (qPCR) protocols were evaluated to diagnose BSF in 110 fatal AFIHS cases, collected in BSF-endemic regions in 2009-2010. Of these, 24 were positive and 86 negative by indirect immunofluorescence (IFA) assay (cutoff IgG and/or IgM >= 128). DNA from these samples was used in the qPCR protocols: one to detect Rickettsia spp. (Citrate synthase gene) and another to determine spotted fever group (SFG) Rickettsia species (OmpA gene). Of the 24 IFA-positive samples, 5 (21%) were positive for OmpA and 9 (38%) for citrate synthase. In the IFA-negative group (n = 86), OmpA and citrate synthase were positive in 23 (27%) and 27 (31%), respectively. These results showed that the 2 qPCR protocols were about twice as sensitive as the IFA test alone (93% concordance). In conclusion, qPCR is a sensitive method for the diagnosis of fatal BSF cases and should be considered for routine surveillance of AFIHS in places like Brazil, where spotted fever-related lethality is high and other endemic diseases like dengue and leptospirosis can mislead diagnosis. (C) 2012 Elsevier GmbH. All rights reserved.

Epistasis among eNOS, MMP-9 and VEGF maternal genotypes in hypertensive disorders of pregnancy

Polymorphisms of the endothelial nitric oxide synthase (eNOS), matrix metalloproteinase-9 (MMP-9) and vascular endothelial growth factor (VEGF) genes were shown to be associated with hypertensive disorders of pregnancy. However, epistasis is suggested to be an important component of the genetic susceptibility to preeclampsia (PE). The aim of this study was to characterize the interactions among these genes in PE and gestational hypertension (GH). Seven clinically relevant polymorphisms of eNOS (T-786C, rs2070744, a variable number of tandem repeats in intron 4 and Glu298Asp, rs1799983), MMP-9 (C-1562T, rs3918242 and -90(CA)(13-25), rs2234681) and VEGF (C-2578A, rs699947 and G-634C, rs2010963) were genotyped by TaqMan allelic discrimination assays or PCR and fragment separation by electrophoresis in 122 patients with PE, 107 patients with GH and a control group of 102 normotensive pregnant (NP) women. A robust multifactor dimensionality reduction analysis was used to characterize gene-gene interactions. Although no significant genotype combinations were observed for the comparison between the GH and NP groups (P>0.05), the combination of MMP-9-1562CC with VEGF-634GG was more frequent in NP women than in women with PE (P<0.05). Moreover, the combination of MMP-9-1562CC with VEGF-634CC or MMP-9-1562CT with VEGF-634CC or-634GG was more frequent in women with PE than in NP women (P<0.05). These results are obscured when single polymorphisms in these genes are considered and suggest that specific genotype combinations of MMP-9 and VEGF contribute to PE susceptibility. Hypertension Research (2012) 35, 917-921; doi:10.1038/hr.2012.60; published online 10 May 2012

Aldosterone deficiency adversely affects pregnancy outcome in mice

Circulating aldosterone levels are increased in human pregnancy. Inadequately low aldosterone levels as present in preeclampsia, a life-threatening disease for both mother and child, are discussed to be involved in its pathogenesis or severity. Moreover, inactivating polymorphisms in the aldosterone synthase gene have been detected in preeclamptic women. Here, we used aldosterone synthase-deficient (AS(-/-)) mice to test whether the absence of aldosterone is sufficient to impair pregnancy or even to cause preeclampsia. AS(-/-) and AS(+/+) females were mated with AS(+/+) and AS(-/-) males, respectively, always generating AS(+/-) offspring. With maternal aldosterone deficiency in AS(-/-) mice, systolic blood pressure was low before and further reduced during pregnancy with no increase in proteinuria. Yet, AS(-/-) had smaller litters due to loss of fetuses as indicated by a high number of necrotic placentas with massive lymphocyte infiltrations at gestational day 18. Surviving fetuses and their placentas from AS(-/-) females were smaller. High-salt diet before and during pregnancy increased systolic blood pressure only before pregnancy in both genotypes and abolished the difference in blood pressure during late pregnancy. Litter size from AS(-/-) was slightly improved and the differences in placental and fetal weights between AS(+/+) and AS(-/-) mothers disappeared. Overall, an increased placental efficiency was observed in both groups paralleled by a normalization of elevated HIF1α levels in the AS(-/-) placentas. Our results demonstrate that aldosterone deficiency has profound adverse effects on placental function. High dietary salt intake improved placental function. In this animal model, aldosterone deficiency did not cause preeclampsia.

The role of adrenal steroidogenesis in arterial hypertension

Adrenal aldosterone production, the major regulator of salt and water retention, is discussed with respect to hypertensive diseases. Physiological aldosterone production is tightly regulated, either stimulated or inhibited, in the adrenal zona glomerulosa by both circulating factors and/or by locally derived endothelial factors. Arterial hypertension caused by volume overload is the leading clinical symptom indicating increased mineralocorticoid hormones. Excessive aldosterone production is seen in adenomatous disease of the adrenals. The balance between stimulatory/proliferative and antagonistic signaling is disturbed by expression of altered receptor subtypes in the adenomas. Increased aldosterone production without a detectable adenoma is the most frequent form of primary aldosteronism. Both increased sensitivity to agonistic signals and activating polymorphisms within the aldosterone synthase gene (CYP11B2) have been associated with excessive aldosterone production. 17alpha-Hydroxylase deficiency and glucocorticoidremediable aldosteronism can also cause excessive mineralocorticoid synthesis. In contrast, the severe form of pregnancy-induced hypertension, preeclampsia, is characterized by a compromised volume expansion in the presence of inappropriately low aldosterone levels. Initial evidence suggests that compromised CYP11B2 is causative, and that administration of NaCl lowered blood pressure in pregnant patients with low aldosterone availability due to a loss of function.

High aldosterone-to-renin variants of CYP11B2 and pregnancy outcome

BACKGROUND: Increased aldosterone concentrations and volume expansion of normal pregnancies are hallmarks of normal pregnancies and blunted in pre-eclampsia. Accordingly, we hypothesized an active mineralocorticoid system to protect from pre-eclampsia. METHODS: In pregnant women (normotensive n = 44; pre-eclamptic n = 48), blood pressure, urinary tetrahydro-aldosterone excretion and activating polymorphisms (SF-1 site and intron 2) of the aldosterone synthase gene (CYP11B2) were determined; 185 non-pregnant normotensive individuals served as control. Amino acid-changing polymorphisms of the DNA- and agonist-binding regions of the mineralocorticoid receptor were evaluated by RT-PCR, SSCP and sequencing. RESULTS: Urinary tetrahydro-aldosterone excretion was reduced in pre-eclampsia as compared to normal pregnancy (P < 0.05). It inversely correlated with blood pressure (r = 0.99, P < 0.04). Homozygosity for activating CYP11B2 polymorphisms was preferably present in normotensive as compared to pre-eclamptic pregnancies, identified (intron 2, P = 0.005; SF-1 site, P = 0.016). Two mutant haplotypes decreased the risk of developing pre-eclampsia (RR 0.16; CI 0.05-0.54; P < 0.001). In contrast, intron 2 wild type predisposed to pre-eclampsia (P < 0.0015). No functional mineralocorticoid receptor mutant has been observed. CONCLUSIONS: High aldosterone availability is associated with lower maternal blood pressure. In line with this observation, gain-of-function variants of the CYP11B2 reduce the risk of developing pre-eclampsia. Mutants of the mineralocorticoid receptor cannot explain the frequent syndrome of pre-eclampsia.