Black Yeast Biota in the Mangrove, in Search of the Origin of the Lethargic Crab Disease (LCD)

Knowledge of natural ecology is essential for a better understanding of pathogenicity and opportunism in black yeast-like fungi. Although etiological agents of diseases caused by these fungi are supposed to originate from the environment, their isolation from nature is difficult. This is probably due to their oligotrophic nature, low competitive ability, and, overall, insufficient data on their natural habitat. We obtained environmental samples from mangrove areas where mortalities by lethargic crab disease (LCD) are reported and areas without disease recorded. Isolation of chaetothyrialean black yeasts and relatives was performed using a highly selective protocol. Species-specific primers were used to determine if these isolates represented Exophiala cancerae or Fonsecaea brasiliensis, two proven agents of LCD, in order to test hypotheses about the origin of the disease. Isolates, identified by morphology as Fonsecaea- or Exophiala-like, were tested specific diagnostic markers for the fungi associated with LCD. Although several black fungi were isolated, the main causative agent of the LCD, E. cancerae, was not found. Molecular markers for F. brasiliensis revealed 10 positive bands for isolates from biofilms on mangrove leaves, branches, and aerial roots, of which four were confirmed by ITS sequencing. The absence of E. cancerae in environmental samples suggests that the species is dependent on the crab, as a genuine pathogen, different from F. brasiliensis, which is probably not dependent on the host species, U. cordatus. However, we did not attempt isolation from the marine water, which may represent the pathway of dispersion of the black yeast species between neighbor mangroves.     

Estimation of the mean distance of closest approach of some heavy metal ions in aqueous solutions: some experimental and theoretical calculations

The estimation of numerical values of the mean distance of closest approach of ions, a, of heavy metal ion salts in aqueous solutions, determined from activity coefficients, as well as from different theoretical approaches, is presented and discussed.     

Depression in Medical School: The Influence of Morningness‐Eveningness

Medical students are at higher risk for depression, affecting not only their lives but also patient care. This article studied a population of medical students engaged in lecture‐based learning regarding the presence of depressive symptoms and its relation to morningness‐eveningness. Depressive symptoms were assessed by the Beck Depressive Inventory scale (BDI>10), and diurnal preference was assessed by the Horne & Östberg Morningness/Eveningness Questionnaire (MEQ). Family history of depression and involvement in regular physical activity were also investigated. A total of 161 students, 77 (47.8%) males, aged 19 to 30 yrs (22.1±2.1) living in a city close to the equator were evaluated. Fifty‐three individuals (32.9%) had depressive symptoms. Depressive individuals showed a trend to be female (p=0.07). Also, female gender showed a non‐significant shift toward morningness. Fifty‐eight (36.0%) subjects participated in regular physical activity. In 57 cases (35.4%), there was a history of depression in the family. Fifteen individuals (9.3%) were definitely evening type, 42 (26.1%) were moderately evening type, 44 (27.3%) were indifferent, 42 (26.1%) were moderately morning type, and 18 (11.2%) were definitely morning type. Family history of depression (OR=0.29, 95% CI=1.37–6.12) and sedentary life (OR=0.28, 95% CI=0.12–0.65) were associated with depressive symptoms. Eveningness was associated with depressive symptoms (OR=0.66, 95% CI=0.50–0.88), and this association remained significant after adjusting for the presence of familial depression and physical activity (OR=0.71, 95% CI=0.52–0.95). In conclusion, depressive symptoms are independently associated with “eveningness” in medical students. These results should be confirmed by future studies involving a larger number of subjects.     

Polyamines affect the cellular growth and structure of pro‐embryogenic masses in Araucaria angustifolia embryogenic cultures through the modulation of proton pump activities and endogenous levels of polyamines

Polyamines (PAs) are abundant polycationic compounds involved in many physiological processes in plants, including somatic embryogenesis. This study investigates the role of PAs on cellular growth and structure of pro‐embryogenic masses (PEMs), endogenous PA and proton pump activities in embryogenic suspension cultures of Araucaria angustifolia. The embryogenic suspension cultures were incubated with putrescine (Put), spermidine (Spd), spermine (Spm) and the inhibitor methylglyoxal‐bis(guanylhydrazone) (MGBG), respectively (1 mM). After 24 h and 21 days, the cellular growth and structure of PEMs, endogenous PA contents and proton pump activities were analyzed. The addition of Spm reduced the cellular growth and promoted the development of PEMs in embryogenic cultures, which could be associated with a reduction in the activities of proton pumps, such as H⁺‐ATPase P‐ and V‐types and H⁺‐PPases, and alterations in the endogenous PA contents. Spm significantly affected the physiology of the A. angustifolia somatic embryogenesis suspension, as it potentially affects cellular growth and structure of PEMs through the modulation of proton pump activities. This work demonstrates the involvement of exogenous PAs in the modulation of cellular growth and structure of PEMs, endogenous PA levels and proton pump activities during somatic embryogenesis. To our knowledge, this study is the first to report a relationship between PAs and proton pump activities in these processes. The results obtained in this study offer new perspectives for studies addressing the role of PAs and proton pump on somatic embryogenesis in this species.     

Impact of iron toxicity on oxidative metabolism in young Eugenia uniflora L. plants

In excess, iron can induce the production and accumulation of reactive oxygen species (ROS), causing oxidative stress. The objective of this work was to evaluate the impact of toxic concentrations of iron (Fe) on the antioxidative metabolism of young Eugenia uniflora plants. Forty-five-day-old plants grown in Hoagland nutrient solution, pH 5.0, were treated with three Fe concentrations, in the form of FeEDTA, during three periods of time. At the end of the treatment, the plants were harvested and relative growth rate, iron content, lipid peroxidation and enzymes and metabolites of the antioxidative metabolism were determined. Iron-treated plants showed higher iron contents, reduced relative growth rates and iron toxicity symptoms in both leaves and roots. There was an increase in lipid peroxidation with increasing Fe, only in the leaves. The enzymatic activities of superoxide dismutase (SOD) and glutathione reductase (GR) increased with increasing Fe concentration and treatment exposure time. The activities of catalase (CAT), peroxidase (POX) and ascorbate peroxidase (APX) also increased with increasing Fe concentration but decreased with increasing treatment exposure time. Glutathione peroxidase activity (GPX) decreased with increasing Fe concentration and exposure time. The ascorbate (AA) and reduced glutathione (GSH) contents and the AA/DHA and GSH/GSSG ratios, in general, increased with increasing Fe concentration and treatment exposure time. The results indicate that under toxic levels of Fe, young E. uniflora plants suffer increased oxidative stress, which is ameliorated through changes in the activities of antioxidative enzymes and in the contents of the antioxidants AA and GSH.     

Ultrasonication of insulin-loaded microgel particles produced by internal gelation: Impact on particle's size and insulin bioactivity

Alginate-dextran sulfate (ADS) microgel has been used to protect insulin from gastrointestinal attack and as a carrier to promote insulin permeation through intestinal epithelium. The throughput of ADS submicron particles generation by emulsification/internal gelation is limited by its wide size distribution.     

Colony Populations and Biomass in Nests of the Amazonian Forest Termite Anoplotermes banksi Emerson (Isoptera: Termitidae)

The arboreal nests of the termite Anoplotermes banksi are abundant in Central Amazonian primary rain forests. Colony size of 7 nests (weight 92–6891 g) varied between 2,593 and 39,256 individuals/nest (1.5 – 22.1 g termites/nest). Average body fresh weight was 0.9 mg for workers and 2.1 mg for alates. Queens weighed 10–30 mg. No relationship between nest weight and maturity was detected, as the ratio of workers to larvae was 1:1, independent of nest size, and alates were found in nests weighing less than 200 g. Nests of A. banksi (12–18 ha -1) accounted for 12–15% of the nest density of all Isopteran species, but the calculated fresh weight of the termites of this species (15–23 mg/m 2) represented only 0.2–0.4% of the total termite biomass in the study area.     

Coagulase-negative staphylococci strains resistant to oxacillin isolated from neonatal blood cultures

Coagulase-negative staphylococci (CoNS) are the microorganisms most frequently isolated from clinical samples and are commonly found in neonatal blood cultures. Oxacillin is an alternative treatment of choice for CoNS infections; however, resistance to oxacillin can have a substantial impact on healthcare by adversely affecting morbidity and mortality. The objective of this study was to detect and characterise oxacillin-resistant CoNS strains in blood cultures of newborns hospitalised at the neonatal ward of the University Hospital of the Faculty of Medicine of Botucatu. One hundred CoNS strains were isolated and the mecA gene was detected in 69 of the CoNS strains, including 73.2% of Staphylococcus epidermidis strains, 85.7% of Staphylococcus haemolyticus strains, 28.6% of Staphylococcus hominis strains and 50% of Staphylococcus lugdunensis strains. Among these oxacillin-resistant CoNS strains, staphylococcal cassette chromosome mec (SCCmec) type I was identified in 24.6%, type II in 4.3%, type III in 56.5% and type IV in 14.5% of the strains. The data revealed an increase in the percentage of CoNS strains isolated from blood cultures from 1991-2009. Furthermore, a predominant SCCmec profile of the oxacillin-resistant CoNS strains isolated from neonatal intensive care units was identified with a prevalence of SCCmec types found in hospital-acquired strains.