Functional ultrastructure of the midgut of the fire ant Solenopsis saevissima Forel 1904 (Formicidae : Myrmicinae)

Solenopsis saevissima has a midgut composed of columnar, regenerative, and goblet cells. The midgut epithelium was covered by a basal lamina. Outside the basal lamina, layers of inner oblique, circular, and outer longitudinal muscles were present. Columnar cells showed a basal plasma membrane containing numerous folds, mitochondria, and the nucleus. Rough endoplasmic reticulum, Golgi bodies, membrane bounded vacuoles, and spherocrystals were found in this region. The apical plasma membrane was constituted by microvilli, which were above a region rich in mitochondria. Regenerative cells were found in groups lying by the basal lamina. Goblet cells were associated with an ion-transporting mechanism between the haemolymph and the midgut epithelium. These cells were lying by the midgut lumen and large microvilli were evident, but the cytoplasmic features were similar to the columnar cells.

Structural and functional characterization of neuwiedase, a nonhemorrhagic fibrin(ogen)olytic metalloprotease from Bothrops neuwiedi snake venom

A fibrino(geno)lytic nonhemorrhagic metalloprotease (neuwiedase) was purified from Bothrops neuwiedi snake venom by a single chromatographic step procedure on a CM-Sepharose column, Neuwiedase represented 4.5% (w/w) of the crude desiccated venom, with an approximate Mr of 20,000 and pI 5.9, As regards the amino acid composition, neuwiedase showed similarities with other metalloproteases, with high proportions of Asx, Glx, Leu, and Ser, Atomic absorption spectroscopy showed that one mole of Zn2+ and one mole of Ca2+ were present per mole olf protein. The cDNA encoding neuwiedase was isolated by RT-PCR from venom gland RNA, using oligonucleotides based on the partially determined amino-acid sequences of this metalloprotease. The fall sequence contained approximately 594 bp, which codified the 198 amino acid residues with an estimated molecular weight of 22,375. Comparison of the nucleotide and amino acid sequences of neuwiedase with those of other snake venom metalloproteases showed a high level of sequential similarity, Neuwiedase has two highly conserved characteristics sequences H(142)E(143)XXH(146)XXG(140)XXH(152) and C164I165M166. The three-dimensional structure of neuwiedase was modeled based on the crystal structure of Crotalus adamanteus Adamalysin II. This model revealed that the zinc binding site region showed a I high structural similarity with other metalloproteases,, the proteolyitc specificity, using the B beta-chain of oxidized insulin as substrate, was shown to be directed to the Ala(14)-Leu(15) and Tyr(16)-Leu(17) peptide bonds which were preferentially hydrolyzed. Neuwiedase is a A alpha,B beta fibrinogenase, Its activity upon the A alpha chain of fibrinogen was detected within 15 min of incubation. The optimal temperature and pH for the degradation of both A alpha and B beta chains were 37 degrees C and 7.4-8.0, respectively. This activity was inhibited by EDTA and 1,10-phenantroline, Neuwiedase also showed proteolytic activity upon fibrin and some components of the extracellular matrix. However, it did not show TAME esterase activity and was not able to inhibit platelet aggregation. (C) 2000 Academic Press.

The influence of the thickness on the functional properties of cassava starch edible films

The properties of edible films are influenced by several factors, including thickness. The purpose of this paper was to study the influence of thickness on the viscoelasticity properties, water vapor permeability, color and opacity of cassava starch edible films. These films were prepared by a casting technique, the film-forming solutions were 1, 2, 3 and 4% (w/v) of starch, heated to 70degreesC. Different thicknesses were obtained by putting 15 to 70 g of each solution on plexiglass plates. After drying at 30degreesC and ambient relative humidity, these samples were placed for 6 days at RH of 75%, at 22degreesC. The sample thicknesses were determined by a digital micrometer (+/-0.001 mm), as the average of nine different points. The viscoelasticity properties were determined by stress relaxation tests with a texture analyser TA.XT2i (SMS), being applied the Burgers model of four parameters. The water vapor permeability was determined with a gravimetric method, and color and opacity were determined using a Miniscan XE colorimeter, operated according to the Hunterlab method. All the tests were carried out in duplicate at 22degreesC. Practically, the four visco-elasticity properties calculated by the Burgers model had the same behavior, increasing with the thickness of all films, according to a power law model. The water vapor permeability and the color difference increased linearly with the thickness (0.013-0.144 mm) of all films prepared with solution of 1 to 4% of starch. on the other hand, the effect of the variation of the thickness over the opacity, was more important in the films with 1 and 2% of starch. It can be concluded that the control of the thickness in the elaboration of starch films by the casting technique is of extreme importance.

Consequences of refuge for the functional response of Dermestes ater (Coleoptera : Dermestidae) to Musca domestica (Diptera : Muscidae)

It is well known that a predator has the potential to regulate a prey population only if the predator responds to increases in prey density and inflicts greater mortality rates. Predators may cause such density-dependent mortality depending on the nature of the functional and numerical responses. Yet, few studies have examined the relationship between the addition of refuges and the characteristic of functional response fits. We investigated whether addition of a refuge changed the type of functional response exhibited by Dermestes ater on Musca domestica, comparing the inherent ability of D. ater to kill houseflies in the absence and in the presence of refuge. An additional laboratory experiment was also carried out to assess handling and searching times exhibited by D. ater. Logistic regression analyses revealed a type III functional response for predator-prey interaction without refuge, and results were described by the random predator equation. The mean number of prey killed did not differ between experimental habitats, indicating that the addition of refuge did not inhibit predation. However, predators that interacted with prey without refuge spent less time searching for prey at higher densities, increasing predatory interaction. We concluded that this interaction may be weak, because data from experiments with refuge fitted poorly to models. However, the high variability and the nonsignificance of the data from the experiment with refuge show the importance of refuge for promoting spatial heterogeneity, which may prevent prey extinction.

Efficient flotation of yeast cells grown in batch culture

A fast flotation assay was used to select new floating yeast strains. The flotation ability did not seem to be directly correlated to total extracellular protein concentration of the culture. However, the hydrophobicity of the cell was definitely correlated to the flotation capacity. The Saccharomyces strains (FLT strains) were highly hydrophobic and showed an excellent flotation performance in batch cultures without additives (flotation agents) and with no need for a special flotation chamber or flotation column. A stable and well-organized structure was evident in the dried foam as shown by scanning electron microscopy which revealed its unique structure showing mummified cells (dehydrated) attached to each other. The attachment among the cells and the high protein concentration of the foams indicated that proteins might be involved in the foam formation. The floating strains (strains FLT) which were not flocculent and showed no tendency to aggregate, were capable of growing and producing ethanol in a synthetic medium containing high glucose concentration as a carbon source. The phenomenon responsible for flotation seems to be quite different from the flocculation phenomenon. (C) 1996 John Wiley & Sons, Inc.

Structural and functional characterization of myotoxin I, a Lys49 phospholipase A(2) homologue from Bothrops moojeni (Caissaca) snake venom

Myotoxin-I (MjTX-I) was purified to homogeneity from the venom of Bothrops moojeni by ion-exchange chromatography on CM-Sepharose. Its molecular weight, estimated by SDS-PAGE, was 13,400 (reduced) or 26,000 (unreduced). The extinction coefficient (E-1.0 cm(1.0 mg/ml)) of MjTX-I was 1.145 at lambda = 278 nm, pH 7.0, and its isoelectric point was 8.2 at ionic strength mu = 0.1. When lyophilized and stored at 4 degrees C, dimeric, trimeric, and pentameric forms of the protein were identified by SDS-PAGE. This heterogeneous sample could be separated into three fractions by gel filtration on Sephadex 6-50. The fractions were analyzed by isoelectric focusing, immunoelectrophoresis, and amino acid composition, which indicated that heterogeneity was the result of different levels of self-association. Protein sequencing indicated that MjTX-I is a Lys49 myotoxin and consists of 121 amino acids (M-r = 13,669), containing a high proportion of basic and hydrophobic residues. It shares a high degree of sequence identity with other Lys49 PLA(2)-like myotoxins, but shows a significantly lower identity with catalytically active Asp49 PLA(2)s. The three-dimensional structure of MjTX-I was modeled based on the crystal structures of three highly homologous Lys49 PLA(2)-like myotoxins. This model showed that the amino acid substitutions are conservative, and mainly the beta-wing region, and the C-terminal extended random coil. MjTX-I displays local myotoxic and edema-inducing activities in mice, and is lethal by intraperitoneal injection, with an LD50 value of 8.5 +/- 0.8 mg/kg, In addition, it is cytotoxic to myoblasts/ myotubes in culture, and disrupts negatively charged liposomes. In comparison with the freshly prepared dimeric sample, the more aggregated forms showed significantly reduced myotoxic activity. However, the edema-inducing activity of MjTX-I was independent of molecular association. Phospholipase A(2) activity on egg yolk, as well as anticoagulant activity, were undetectable both in the native and in the more associated forms. His, Tyr, and Trp residues of the toxin were chemically modified by specific reagents. Although the myotoxic and lethal activities of the modified toxins were reduced by these treatments, neither its edema-inducing or Liposome-disrupting activities were significantly altered. Rabbit antibodies to native MjTX-I cross-reacted with the chemically modified forms, and both the native and modified MjTX-I preparations were recognized by antibodies against the C-terminal region 115-129 of myotoxin II from B. asper, a highly Lys49 PLA(2)-homologue with high sequencial similarity. (C) 2000 Academic Press.

Flotation for cell recovery from small volumes of yeast cultures

Flotation or cell recovery in foams (proportion of the total cells in the medium transferred to the foam) and flotation efficiency (proportion of the cells transferred from an initial volume of medium equal to the residual volume after flotation) are functions of time, aeration rate, initial volume of medium, and initial concentration of cells. Cell recovery reached constant values (around 96.4 +/- 6.3%) and flotation efficiency decreased (owing to increases in the liquid content of the foam), with increases in air how rate (above 6-7 ml air s(-1)) and volumes of medium (above 11 ml) added to the column. Increases in concentration of cells in the medium led to increases in the concentration of cells in the foam.

Disulfide Biochemistry in 2-Cys Peroxiredoxin: Requirement of Glu50 and Arg146 for the Reduction of Yeast Tsa1 by Thioredoxin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nutritional status and functional capacity of hospitalized elderly

Background: The nutritional status of the aging individual results from a complex interaction between personal and environmental factors. A disease influences and is influenced by the nutritional status and the functional capacity of the individual. We asses the relationship between nutritional status and indicators of functional capacity among recently hospitalized elderly in a general hospital.Methods: A cross-sectional study was done with 240 elderly (women, n = 127 and men, n = 113) hospitalized in a hospital that provides care for the public and private healthcare systems. The nutritional status was classified by the MNA (Mini Nutritional Assessment) into: malnourished, risk of malnutrition and without malnutrition (adequate). The functional autonomy indicators were obtained by the self-reported Instrumental Activity of Daily Living (IADL) and Activity of Daily Living (ADL) questionnaire. The chi-square test was used to compare the proportions and the level of significance was 5%.Results: Among the assessed elderly, 33.8% were classified as adequate regarding nutritional status; 37.1% were classified as being at risk of malnutrition and 29.1% were classified as malnourished. All the IADL and ADL variables assessed were significantly more deteriorated among the malnourished individuals. Among the ADL variables, eating partial (42.9%) or complete (12.9%) dependence was found in more than half of the malnourished elderly, in 13.4% of those at risk of malnutrition and in 2.5% of those without malnutrition.Conclusion: There is an interrelationship between the nutritional status of the elderly and reduced functional capacity.

Functional activity of neutrophils and systemic inflammatory response of Down's syndrome patients with periodontal disease

Periodontal disease (PD) is characterized as an inflammatory process that compromises the support and protection of the periodontium. Patients with Down's syndrome (DS) are prone to develop PD. Neutrophils (NE) are the first line of defense against infection and their absence sets the stage for disease. Aim: To compare the activity and function of NE in the peripheral blood from DS patients with and without PD, assisted at the Center for Dental Assistance to Patients with Special Needs affiliated with the School of Dentistry of Araçatuba, Brazil. Methods: Purified NE were collected from peripheral blood of 22 DS patients. NE were used to detect the 5-lypoxigenase (5-LO) expression by RT-PCR. Plasma from peripheral blood was collected to measure tumor necrosis factor-a (TNF-α) and interleukin-8 (IL-8) by ELISA and nitrite (NO 3) using a Griess assay. Results: Data analysis demonstrated that DS patients with PD present high levels of TNF-a and IL-8 when compared with DS patients without PD. However, there was no statistically significant difference in the levels of NO 3 production between the groups. The levels of the inflammatory mediator 5-LO expression increased in DS patients with PD. Conclusions: According with these results, it was concluded that TNF-α and IL-8 are produced by DS patients with PD. Furthermore, DS patients with PD presented high levels of 5-LO expression, suggesting the presence of leukotriene B 4 (LTB 4) in PD, thus demonstrating that the changes in NE function due to the elevation of inflammatory mediators contribute to PD.

Productive structure and the functional distribution of income: an application of the input-output model

Includes bibliography

Antioxidant Effect of Melatonin on the Functional Activity of Colostral Phagocytes in Diabetic Women

Melatonin is involved in a number of physiological and oxidative processes, including functional regulation in human milk. The present study investigated the mechanisms of action of melatonin and its effects on the functional activity of colostral phagocytes in diabetic women. Colostrum samples were collected from normoglycemic (N = 38) and diabetic (N = 38) women. We determined melatonin concentration, superoxide release, bactericidal activity and intracellular Ca2+ release by colostral phagocytes treated or not with 8-(Diethylamino) octyl-3,4,5-trimethoxybenzoate hydrochloride (TMB-8) and incubated with melatonin and its precursor (N-acetyl-serotonin-NAS), antagonist (luzindole) and agonist (chloromelatonin-CMLT). Melatonin concentration was higher in colostrum samples from hyperglycemic than normoglycemic mothers. Melatonin stimulated superoxide release by colostral phagocytes from normoglycemic but not hyperglycemic women. NAS increased superoxide, irrespective of glycemic status, whereas CMTL increased superoxide only in cells from the normoglycemic group. Phagocytic activity in colostrum increased significantly in the presence of melatonin, NAS and CMLT, irrespective of glycemic status. The bactericidal activity of colostral phagocytes against enterophatogenic Escherichia coli (EPEC) increased in the presence of melatonin or NAS in the normoglycemic group, but not in the hyperglycemic group. Luzindole blocked melatonin action on colostrum phagocytes. Phagocytes from the normoglycemic group treated with melatonin exhibited an increase in intracellular Ca2+ release. Phagocytes treated with TMB-8 (intracellular Ca2+ inhibitor) decreased superoxide, bactericidal activity and intracellular Ca2+ release in both groups. The results obtained suggest an interactive effect of glucose metabolism and melatonin on colostral phagocytes. In colostral phagocytes from normoglycemic mothers, melatonin likely increases the ability of colostrum to protect against EPEC and other infections. In diabetic mothers, because maternal hyperglycemia modifies the functional activity of colostrum phagocytes, melatonin effects are likely limited to anti-inflammatory processes, with low superoxide release and bactericidal activity. © 2013 Morceli et al.

Functional extinction of birds drives rapid evolutionary changes in seed size

Local extinctions have cascading effects on ecosystem functions, yet little is known about the potential for the rapid evolutionary change of species in human-modified scenarios. We show that the functional extinction of large-gape seed dispersers in the Brazilian Atlantic forest is associated with the consistent reduction of the seed size of a keystone palm species. Among 22 palm populations, areas deprived of large avian frugivores for several decades present smaller seeds than nondefaunated forests, with negative consequences for palm regeneration. Coalescence and phenotypic selection models indicate that seed size reduction most likely occurred within the past 100 years, associated with human-driven fragmentation. The fast-paced defaunation of large vertebrates is most likely causing unprecedented changes in the evolutionary trajectories and community composition of tropical forests.

Time-course morphological and functional disorders of the kidney induced by long-term high-fat diet intake in female rats

BackgroundEvidence is emerging that highlights the far-reaching consequences of a high-fat diet (HFD) on kidney morphology and function disorders.MethodsThe present study was performed on 3-, 5-, 7- and 9-week-old HFD female rats compared with the appropriate gender and age-matched animals. We evaluated the kidney expression of angiotensin type II receptor and fibrotic and epithelial-to-mesenchymal transition (EMT) markers, by immunoblotting and immunohistochemical and histological techniques, in parallel with kidney function.ResultsIn the current study, the time-course HFD-treated group showed, by immunoblotting and immunohistochemical analysis, an early time-course increase in the expression of transforming growth factor β-1 (TGFβ-1) in the entire kidney of HFD-treated rats, compared with that observed in the control group. Simultaneously, the study shows a transient increase in the expression of ZEB2 in the HFD whole kidney accompanied by a fall in the E-cadherin expression and increased collagen and fibronectin deposition. A pronounced decrease in fractional urinary sodium excretion was also demonstrated in the long-term HFD-treated rats. The decreased FENa + was accompanied by a fall in FEPNa + and FEPP Na +, which occurred in association with significantly decreased CCr and, certainly on the sodium-filtered load. The reduction in the glomerular filtration rate (GFR) occurred in parallel to proteinuria and glomerular desmin overexpression.ConclusionsThe results of the current study suggest that podocyte injury in parallel with observed proteinuria and evidence of EMT transformation are associated with long-term loss of kidney function and renal sodium and water retention. © 2013 The Author. All rights reserved.

The functional biogeography of species: Biogeographical species roles of birds in Wallacea and the West Indies

Biogeographical systems can be analyzed as networks of species and geographical units. Within such a biogeographical network, individual species may differ fundamentally in their linkage pattern, and therefore hold different topological roles. To advance our understanding of the relationship between species traits and large-scale species distribution patterns in archipelagos, we use a network approach to classify birds as one of four biogeographical species roles: peripherals, connectors, module hubs, and network hubs. These roles are based upon the position of species within the modular network of islands and species in Wallacea and the West Indies. We test whether species traits - including habitat requirements, altitudinal range-span, feeding guild, trophic level, and body length - correlate with species roles. In both archipelagos, habitat requirements, altitudinal range-span and body length show strong relations to species roles. In particular, species that occupy coastal- and open habitats, as well as habitat generalists, show higher proportions of connectors and network hubs and thus tend to span several biogeographical modules (i.e. subregions). Likewise, large body size and a wide altitudinal range-span are related to a wide distribution on many islands and across several biogeographical modules. On the other hand, species restricted to interior forest are mainly characterized as peripherals and, thus, have narrow and localized distributions within biogeographical modules rather than across the archipelago-wide network. These results suggest that the ecological amplitude of a species is highly related to its geographical distribution within and across bio geographical subregions and furthermore supports the idea that large-scale species distributions relate to distributions at the local community level. We finally discuss how our biogeographical species roles may correspond to the stages of the taxon cycle and other prominent theories of species assembly. © 2013 The Authors.