Interactions between different predator–prey states: a method for the derivation of the functional and numerical response

Journal of Mathematical Biology - In this paper we introduce a formal method for the derivation of a predator’s functional response from a system of fast state transitions of the prey or...     

Growth Arrest Specific 1 (GAS1) Is Abundantly Expressed in the Adult Mouse Central Nervous System

Growth arrest specific 1 (GAS1) is a pleiotropic protein that induces apoptosis and cell arrest in different tumors, but it is also involved in the development of the nervous system and other tissues and organs. This dual ability is likely caused by its capacity to interact both by inhibiting the intracellular signaling cascade induced by glial cell-line derived neurotrophic factor and by facilitating the activity of the sonic hedgehog pathway. The presence of GAS1 mRNA has been described in adult mouse brain, and here we corroborated this observation. We then proceeded to determine the distribution of the protein in the adult central nervous system (CNS). We detected, by western blot analysis, expression of GAS1 in olfactory bulb, caudate-putamen, cerebral cortex, hippocampus, mesencephalon, medulla oblongata, cerebellum, and cervical spinal cord. To more carefully map the expression of GAS1, we performed double-label immunohistochemistry and noticed expression of GAS1 in neurons in all brain areas examined. We also observed expression of GAS1 in astroglial cells, albeit the pattern of expression was more restricted than that seen in neurons. Briefly, in the present article, we report the widespread distribution and cellular localization of the GAS1 native protein in adult mammalian CNS.     

Erythematous Oral Candidiasis in Patients with Controlled Type II Diabetes Mellitus and Complete Dentures

Diabetes mellitus (DM) is a systemic condition characterized by a deficient sugar metabolism, which affects the immune system and favors the development of yeasts. The aim of the present study was to perform biochemical, morphological, exoenzyme analyses of Candida species and the molecular identification (DNA) of C. albicans in patients with type II diabetes mellitus. The exoenzyme quantification was compared to non-diabetic patients as controls. Two hundred and seventy-four patients who make use of complete dentures were evaluated, 28 of whom had diabetes and erythematous oral candidiasis. Other thirty patients presented the same clinical feature but without diabetes. Samples were isolated for biochemical identification (auxonogram), morphological identification (production of germ tubes) and PCR molecular identification (DNA). The capability of the Candida samples in producing phospholipases and proteinases was also determined. The diabetic patients had a greater diversity of Candida species (Fischer’s exact test, P = 0.04). The production of proteinases by C. albicans in patients with diabetes was greater than in the control group (unpaired “t” test P < 0.003). However, there was no difference between groups for phospholipase production (unpaired “t” test P > 0.05). It was concluded that patients with controlled DM exhibited systemic conditions predisposing C. albicans proteinase increased production.     

Visual contrast sensitivity in patients with impairment of functional independence after stroke

ABSTRACT: BACKGROUND: Stroke has been considered a serious public health problem in many countries, accounting for complex disorders involving perception, such as visual, cognitive and functional deficits. The impact of stroke on the visual perception of individuals with impairments in functional independence was investigated. METHODS: We measured changes in functional independence and visual function in 40 patients with stroke (M = 52.3, SD = 0.65) and 10 controls (M = 52.5, SD = 0.66). The patients were divided into four subgroups following the Barthel Index (Group A: 20--35, serious dependence; Group B: 40--55, moderate dependence; Group C: 60--95, mild dependence; and Group D: 100 points, independence). Visual function was evaluated using the Contrast Sensitivity Function (CSF). The contrast threshold was measured using a temporal, two-alternative, forced-choice psychophysical method. RESULTS: The results show significant differences in CSF between healthy volunteers and patients with stroke (F (1.56) = 151.2, p < 0.001) for all frequencies (F (2.56) = 125.96, p < 0.001). The results also show that patients with low functional independence had lower contrast sensitivity than those with greater functional independence (F (3.56) = 344.82, p < 0.001). CONCLUSIONS: An association exists between CSF and a worsening in the functional potential for performing daily living activities. Our results suggest that the CSF can be used as a diagnostic tool to analyze visual function associated with deficits in functional independence after stroke. These findings should be considered across the continuum of care for these patients.     

Function and redundancy of the chaplin cell surface proteins in aerial hypha formation, rodlet assembly, and viability in Streptomyces coelicolor

The chaplins are a family of eight secreted proteins that are critical for raising aerial hyphae in Streptomyces coelicolor. These eight chaplins can be separated into two main groups: the long chaplins (ChpA to -C) and the short chaplins (ChpD to -H). The short chaplins can be further subdivided on the basis of their abilities to form intramolecular disulfide bonds: ChpD, -F, -G, and -H contain two Cys residues, while ChpE has none. A "minimal chaplin strain" containing only chpC, chpE, and chpH was constructed and was found to raise a substantial aerial mycelium. This strain was used to examine the roles of specific chaplins. Within this strain, the Cys-containing ChpH was identified as the major polymerization unit contributing to aerial hypha formation and assembly of an intricate rodlet ultrastructure on the aerial surfaces, and the two Cys residues were determined to be critical for its function. ChpC augmented aerial hypha formation and rodlet assembly, likely by anchoring the short chaplins to the cell surface, while ChpE was essential for the viability of wild-type S. coelicolor. Interestingly, the lethal effects of a chpE null mutation could be suppressed by the loss of the other chaplins, the inactivation of the twin arginine translocation (Tat) secretion pathway, or the loss of the rodlins.     

Incidence of Rotavirus and Circulating Genotypes in Northeast Brazil during 7 Years of National Rotavirus Vaccination

Background and Aims

Rotavirus causes severe diarrhoea and Brazil introduced the Rotarix G1P[8] vaccine in 2006. We aimed to describe changes in rotavirus incidence and diarrhoea epidemiology before and after vaccine introduction.

Methods

Design: (i) hospital-based survey of children with diarrhoea (2006–2012); (ii) diarrhea-mortality and hospitalization surveillance (1999–2012).

Setting

(i) Aracaju and (ii) state and national level.

Results

1841 children were enrolled and 231 (12.5%) had rotavirus. Rotavirus was less frequent from January-June than from July-December (9.4% versus 20.9%, p<0.01), but the seasonal variation was less defined after 2009. Very few rotavirus cases (8–3.9%) were detected in 2011, with an increase in 2012 (13–18.5%). In 2006, unvaccinated children were more likely to have rotavirus, but thereafter unvaccinated and vaccinated children had equally low incidence. Older children and those with rotavirus were more likely to have severe diarrhea episodes. The most frequent genotype from 2006 to 2010 was G2P[4]; except in 2009, when most cases were G1P[8]. Very few G2P[4] were detected from 2011 and 50% cases in 2012 were G8P[4]. Diarrhoea-hospitalizations decreased nationally from 89,934 (2003) to 53,705 (2012; 40.3% reduction) and in the state from 1729 to 748 (56.7% reduction). Diarrhoea-deaths decreased nationally from 4368 in 1999 to 697 in 2012 (84% reduction, p<0.001) and in the state from 132 to 18 (86% reduction). These changes were much larger after vaccine introduction.

Conclusions

The vaccine was associated with substantial reductions in rotavirus incidence and diarrhoea-hospitalizations and deaths. The G2P[4] genotype predominance disappeared over time and may be replaced by other heterotypic genotypes.