Airborne pollen patterns in Mar del Plata atmosphere (Argentina) and its relationship with meteorological conditions

This work is part of a series of aerobiological researches conducted in the city of Mar del Plata, Argentina. The annual, seasonal and daily features of the pollen cloud were analyzed over 2 years, together with the effects of the meteorological variables. Cupressaceae amounted to 75 and 54% of the annual total in each year, and it was analyzed separately due to its proven overrepresentation. Eighty-five pollen types were registered during the 2 years, bearing a similar annual pattern (more than 50% from August to November, December also being an important month). Arboreal pollen predominated between late winter and spring (61 and 49% of the annual total), while non-arboreal pollen did so from late spring to summer. The observed seasonality was significantly correlated with the monthly mean temperatures and associated with its effect on phenology. No significant differences along the day were detected between years and 50% of the daily total was recorded between 1000 and 1600 hours. The maximum concentration was registered at 1000 hours in spring and summer, but later in autumn and winter. Regarding the hourly scale, the significant correlation of total pollen with temperature and wind speed was positive, albeit negative with relative humidity. These effects are linked to airborne pollen release and transport. The role rainfall plays on airborne pollen is discussed. To interpret the results, it is important to consider the time scale at which the aerobiological phenomenon is analyzed.     

Heterologous expression in Escherichia coli of Neurospora crassa neutral trehalase as an active enzyme

Neutral trehalase from Neurospora crassa was expressed in Escherichia coli as a polypeptide of 84 kDa in agreement with the theoretical size calculated from the corresponding cDNA. The recombinant neutral trehalase, purified by affinity chromatography exhibited a specific activity of 80–150 mU/mg protein. Optima of pH and temperature were 7.0 and 30 °C, respectively. The enzyme was absolutely specific for trehalose, and was quite sensitive to incubation at 40 °C. The recombinant enzyme was totally dependent on calcium, and was inhibited by ATP, copper, silver, aluminium and cobalt. K_M was 42 mM, and V_max was 30.6 nmol of glucose/min. The recombinant protein was phosphorylated by cAMP-dependent protein kinase, but not significantly activated. Immunoblotting with polyclonal antiserum prepared against the recombinant protein showed that neutral trehalase protein levels increased during exponential phase of N. crassa growth and dropped at the stationary phase. This is the first report of a neutral trehalase produced in E. coli with similar biochemical properties described for fungi native neutral trehalases, including calcium-dependence.     

First report of human myiasis in GoiáS state, Brazil: frequency of different types of myiasis, their various etiological agents, and associated factors

The objective of this study was to show which species of flies are responsible for human myiasis in the Brazilian state of Goiás and to determine the frequency of cases. Patients at the Clinical Hospital of the Federal University of Goiás (UFG) were examined, and any fly larvae found in their wounds were collected for taxonomic identification. First instar larvae were observed using light microscopy; second and third instars were examined using stereoscopy. The following screwworm flies were observed, in decreasing order of prevalence: Cochliomyia hominivorax, Sarcodexia lambens, Dermatobia hominis, Chrysomya albiceps, Chrysomya megacephala, Lucilia cuprina, and Eristalis tenax. Myiasis was most frequent in the legs in adults, male patients, elderly people, and people of reproductive age. It was lowest in children, females, and patients with neurologic or psychiatric disorders. Frequency was high in patients living in low socioeconomic conditions with poor personal hygiene. Education and sanitation measures are needed to counteract this situation.     

Identification of two proteins that interact with the Erp virulence factor from Mycobacterium tuberculosis by using the bacterial two-hybrid system

Background  

The exported repetitive protein (erp) gene encodes a secreted 36-kDa protein with a central domain containing several proline-glycine-leucine-threonine-serine (PGLTS) repeats. It has been demonstrated that erp is a virulence-associated factor since the disruption of this gene impairs the growth of Mycobacterium bovis and Mycobacterium tuberculosis in mice.     

Modification of plant hormone levels and signaling as a tool in plant biotechnology

Plant hormones are signal molecules, present in trace quantities, that act as major regulators of plant growth and development. They are involved in a wide range of processes such as elongation, flowering, root formation and vascular differentiation. For many years, agriculturists have applied hormones to their crops to either increase the yield, or improve the quality of the commercial product. Nowadays, the knowledge of hormone biosynthesis, degradation and signaling pathways has allowed the utilization of biotechnological tools to further improve the main agricultural crops. Natural or artificial mutants, with impaired functioning of the corresponding genes, have been adopted because of their superior phenotype in specific agricultural traits. In addition, transgenic plants have been generated to regulate internal hormone levels, or their signaling pathways, resulting in some crops that have revolutionized agriculture.     

Protein tyrosine phosphatases regulate arachidonic acid release, StAR induction and steroidogenesis acting on a hormone-dependent arachidonic acid-preferring acyl-CoA synthetase

The activation of the rate-limiting step in steroid biosynthesis, that is the transport of cholesterol into the mitochondria, is dependent on PKA-mediated events triggered by hormones like ACTH and LH. Two of such events are the protein tyrosine dephosphorylation mediated by protein tyrosine phosphatases (PTPs) and the release of arachidonic acid (AA) mediated by two enzymes, ACS4 (acyl-CoA synthetase 4) and Acot2 (mitochondrial thioesterase). ACTH and LH regulate the activity of PTPs and Acot2 and promote the induction of ACS4. Here we analyzed the involvement of PTPs on the expression of ACS4. We found that two PTP inhibitors, acting through different mechanisms, are both able to abrogate the hormonal effect on ACS4 induction. PTP inhibitors also reduce the effect of cAMP on steroidogenesis and on the level of StAR protein, which facilitates the access of cholesterol into the mitochondria. Moreover, our results indicate that exogenous AA is able to overcome the inhibition produced by PTP inhibitors on StAR protein level and steroidogenesis. Then, here we describe a link between PTP activity and AA release, since ACS4 induction is under the control of PTP activity, being a key event for AA release, StAR induction and steroidogenesis.     

Antimutagenicity of ursolic acid and oleanolic acid against doxorubicin-induced clastogenesis in Balb/c mice

Ursolic acid (UA) and oleanolic acid (OA) are triterpenoid compounds found in food, medicinal herbs and various other plants in free form or bound to glycosides. Both substances are known for their antimicrobial, hepatoprotective, anti-inflammatory, antiallergic, antiviral and cytotoxic activities. In the present study, we evaluated the antimutagenic potential of UA and OA using the micronucleus test in peripheral blood and bone marrow of Balb/c mice. The animals were divided into 10 treatment groups: mice treated with UA (80 mg/kg b.w.); OA (80 mg/kg b.w.); a mixture of UA and OA (80 mg/kg b.w.); the antineoplastic agent doxorubicin (DXR, 90 mg/kg b.w.); DMSO and DXR; UA and DXR; OA and DXR; UA, OA and DXR, and negative and solvent controls. UA, OA and a mixture of UA and OA were administered to the animals by gavage, followed by the intraperitoneal injection of DXR. The results showed a significant reduction in micronucleus frequency in the groups concomitantly treated with the triterpenoid compounds and DXR compared to that treated with DXR alone. The present results demonstrate the antimutagenic activity of UA and OA under the experimental conditions used in this study.     

Basal and Fasting/Refeeding‐regulated Tissue Levels of Endogenous PPAR‐α Ligands in Zucker Rats

N‐oleoylethanolamine (OEA) and N‐palmitoylethanolamine (PEA) are endogenous lipids that activate peroxisome proliferator–activated receptor‐α with high and intermediate potency, and exert anorectic and anti‐inflammatory actions in rats, respectively. We investigated OEA and PEA tissue level regulation by the nutritional status in lean and obese rats. OEA and PEA levels in the brainstem, duodenum, liver, pancreas, and visceral (VAT) or subcutaneous (SAT) adipose tissues of 7‐week‐old wild‐type (WT) and Zucker rats, fed ad libitum or following overnight food deprivation, with and without refeeding, were measured by liquid chromatography–mass spectrometry. In WT rats, duodenal OEA, but not PEA, levels were reduced by food deprivation and restored by refeeding, whereas the opposite was observed for OEA in the pancreas, and for both mediators in the liver and SAT. In ad lib fed Zucker rats, PEA and OEA levels were up to tenfold higher in the duodenum, slightly higher in the brainstem, and lower in the other tissues. Fasting/refeeding‐induced changes in OEA levels were maintained in the duodenum, liver, and SAT, and lost in the pancreas, whereas fasting upregulated this compound also in the VAT. The observed changes in OEA levels in WT rats are relevant to the actions of this mediator on satiety, hepatic and adipocyte metabolism, and insulin release. OEA dysregulation in Zucker rats might counteract hyperphagia in the duodenum, but contribute to hyperinsulinemia in the pancreas, and to fat accumulation in adipose tissues and liver. Changes in PEA levels might be relevant to the inflammatory state of Zucker rats.