Coxiella burnetii, the agent of Q fever in Brazil: its hidden role in seronegative arthritis and the importance of molecular diagnosis based on the repetitive element IS1111 associated with the transposase gene

Coxiella burnetii is the agent of Q fever , an emergent worldwide zoonosis of wide clinical spectrum. Although C. burnetii infection is typically associated with acute infection, atypical pneumonia and flu-like symptoms, endocarditis, osteoarticular manifestations and severe disease are possible, especially when the patient has a suppressed immune system; however, these severe complications are typically neglected. This study reports the sequencing of the repetitive element IS1111 of the transposase gene of C. burnetii from blood and bronchoalveolar lavage (BAL) samples from a patient with severe pneumonia following methotrexate therapy, resulting in the molecular diagnosis of Q fever in a patient who had been diagnosed with active seronegative polyarthritis two years earlier. To the best of our knowledge, this represents the first documented case of the isolation of C. burnetii DNA from a BAL sample.     

Enzymatic synthesis of ascorbyl ester derived from linoleic acid

Bioprocess and Biosystems Engineering - Antioxidants are substances that defend cells against damage, kidnapping and destroying free radicals. They have been largely used in the food industry due...     

Production and characterization of collagenase from a new Amazonian Bacillus cereus strain

Abstract

A new collagenase producing a strain of Bacillus cereus, isolated from the pollen of a bee of Amazon Region (Brazil), had its enzyme characterized and the production medium composition and culture conditions enhanced. A two-level design on three factors, namely initial medium pH, the substrate (gelatin) concentration and agitation intensity, allowed identifying the first two variables as the most significant ones, while a central composite design (CCD) was subsequently used to identify their optimal levels. Statistics highlighted maximized collagenolytic activity when substrate concentration and initial medium pH were selected at their highest levels (positive effects), whereas agitation intensity at the lowest (negative effect). Triplicate runs performed under predicted optimal conditions (pH 7.8 and 1.7% gelatin concentration) yielded a collagenolytic activity (305.39?±?5.15?U) 4.6- to 15-fold those obtained with the preliminary design. The enzyme displayed optimum activity at 45?°C and pH 7.2, was stable over wide ranges of pH values and temperatures (7.2–11.0 and 25–50?°C, respectively) and was strongly inhibited by 10?mM phenylmethylsulphonyl fluoride. The zymogram showed two prominent bands at 50 and 76?kDa. These results are a first attempt to elucidate the features of this new collagenase, its production conditions, and possible scale-up.     

Protein arginine methyl transferases-3 and -5 increase cell surface expression of cardiac sodium channel

The α-subunit of the cardiac voltage-gated sodium channel (Na_V1.5) plays a central role in cardiomyocyte excitability. We have recently reported that Na_V1.5 is post-translationally modified by arginine methylation. Here, we aimed to identify the enzymes that methylate Na_V1.5, and to describe the role of arginine methylation on Na_V1.5 function. Our results show that protein arginine methyl transferase (PRMT)-3 and -5 methylate Na_V1.5 in vitro, interact with Na_V1.5 in human embryonic kidney (HEK) cells, and increase Na_V1.5 current density by enhancing Na_V1.5 cell surface expression. Our observations are the first evidence of regulation of a voltage-gated ion channel, including calcium, potassium, sodium and TRP channels, by arginine methylation.     

Interaction of proliferation cell nuclear antigen (PCNA) with c-Abl in cell proliferation and response to DNA damages in breast cancer

Cell proliferation in primary and metastatic tumors is a fundamental characteristic of advanced breast cancer. Further understanding of the mechanism underlying enhanced cell growth will be important in identifying novel prognostic markers and therapeutic targets. Here we demonstrated that tyrosine phosphorylation of the proliferating cell nuclear antigen (PCNA) is a critical event in growth regulation of breast cancer cells. We found that phosphorylation of PCNA at tyrosine 211 (Y211) enhanced its association with the non-receptor tyrosine kinase c-Abl. We further demonstrated that c-Abl facilitates chromatin association of PCNA and is required for nuclear foci formation of PCNA in cells stressed by DNA damage as well as in unperturbed cells. Targeting Y211 phosphorylation of PCNA with a cell-permeable peptide inhibited the phosphorylation and reduced the PCNA-Abl interaction. These results show that PCNA signal transduction has an important impact on the growth regulation of breast cancer cells.     

How the Leopard Hides Its Spots: ASIP Mutations and Melanism in Wild Cats

The occurrence of melanism (darkening of the background coloration) is documented in 13 felid species, in some cases reaching high frequencies at the population level. Recent analyses have indicated that it arose multiple times in the Felidae, with three different species exhibiting unique mutations associated with this trait. The causative mutations in the remaining species have so far not been identified, precluding a broader assessment of the evolutionary dynamics of melanism in the Felidae. Among these, the leopard (Panthera pardus) is a particularly important target for research, given the iconic status of the ‘black panther’ and the extremely high frequency of melanism observed in some Asian populations. Another felid species from the same region, the Asian golden cat (Pardofelis temminckii), also exhibits frequent records of melanism in some areas. We have sequenced the coding region of the Agouti Signaling Protein (ASIP) gene in multiple leopard and Asian golden cat individuals, and identified distinct mutations strongly associated with melanism in each of them. The single nucleotide polymorphism (SNP) detected among the P. pardus individuals was caused by a nonsense mutation predicted to completely ablate ASIP function. A different SNP was identified in P. temminckii, causing a predicted amino acid change that should also induce loss of function. Our results reveal two additional cases of species-specific mutations implicated in melanism in the Felidae, and indicate that ASIP mutations may play an important role in naturally-occurring coloration polymorphism.     

A characterization of a MutM/Fpg ortholog in sugarcane--A monocot plant

Plant genomic projects, such as Arabidopsis thaliana, rice, and maize, have provided excellent tools for comparative genome analysis on Base Excision DNA Repair (BER). A data-mining study associated with the SUCEST Genome project identified two EST clusters that shared homology to the bacteria MutM/Fpg protein. Comparative analyses presented here show a duplication of the MutM/Fpg gene in sugarcane, wheat and rice. The complementation assays show that both cDNAs from sugarcane are able to complement the Fpg and MutY-glycosylase deficiency in a double mutant Escherichia coli strain (CC104mutMmutY), reducing the spontaneous mutation frequency by 10-fold. The expression analyses by semi-quantitative RT-PCR show that these two mRNAs have different expression levels.     

Stilbenoid pterostilbene complexed with cyclodextrin preserves left ventricular function after myocardial infarction in rats: possible involvement of thiol proteins and modulation of phosphorylated GSK-3β

Abstract

Oxidative stress alters signalling pathways for survival and cell death favouring the adverse remodelling of postmyocardial remnant cardiomyocytes, promoting functional impairment. The administration of pterostilbene (PTS), a phytophenol with antioxidant potential, can promote cardioprotection and represents a therapeutic alternative in acute myocardial infarction (AMI). The present study aims to explore the effects of oral administration of PTS complexed with hydroxypropyl-β-cyclodextrin HPβCD (PTS:HPβCD complex) on the glutathione cycle, thiol protein activities and signalling pathways involving the protein kinase B (AKT) and glycogen synthase kinase-3β (GSK-3β) proteins in the left ventricle (LV) of infarcted rats. Animals were submitted to acute myocardial infarction through surgical ligation of the descending anterior branch of the left coronary artery and received over 8 days, by gavage, PTS:HPβCD complex at dose of 100?mg?kg^?1?day^?1 (AMI?+?PTS group) or vehicle (aqueous solution with HPβCD) divided into Sham-operated (SHAM) and infarcted (AMI) groups. The results showed that the PBS: HPβCD complex decreased lipid peroxidation, prevented the decrease in thioredoxin reductase (TRxR) activity, and increased the activity of glutathione-S-transferase (GST) and glutaredoxin (GRx). Additionally, the expression of nuclear factor-erythroid two (Nrf2) and p-GSK-3β was increased, whereas the p-GSK-3β/GSK-3β ratio was reduced in the LV of the infarcted animals. Overall, the PTS:HPβCD complex modulates activity of thiol-dependent enzymes and induces to the expression of antioxidant proteins, improving systolic function and mitigating the adverse cardiac remodelling post infarction.