Floristics, structure and soil of insular vegetation in four quartzite-sandstone outcrops of "Chapada Diamantina", Northeast Brazil

Soil islands on rocky surfaces often harbor aggregated vegetation that consists of insular plant communities. These islands are typical of the rocky outcrops and in various parts of Brazil form the so-called "campos rupestres" vegetation. Four of such sites have been selected in the state of Bahia, Northeast Brazil, for this comparative study on floristics and vegetation structure: three areas situated inside the "Parque Nacional da Chapada Diamantina" (Guiné, Fumaça and "Gerais da Fumaça") and one is at the border of the Environmental Protection Area of "Marimbus-Iraquara" ("Mãe Inácia"). All occurring vegetation islands were studied in four random plots of 10 × 10 m per site. Soil was often shallow, sandy and acidic. Vascular plant species were determined, with respective life forms and canopy coverage areas. The total number of species when all four sites were added was 135, and the number of species per island varied from 2 to 32. The areas of the 214 soil islands varied from 0.015 to 91.9 m², totaling 568 m² in the four sites. Monocotyledon families were dominant, essentially Velloziaceae, as well as Orchidaceae, Bromeliaceae, Amaryllidaceae and Cyperaceae. Among the eudicotyledons, dominant families were mainly Clusiaceae, Asteraceae and Melastomataceae. The biological spectra revealed that phanerophytes and hemicryptophytes predominated among the life forms, while chamaephytes had the largest coverage area. Epilithic and desiccant chamaephytes composed the most conspicuous interspecific associations, and were probably related to early successional processes. Sites closest to one another were not the most similar in structure, indicating that other factors more relevant than distance might be involved in the abundance of species in space.

Leaf and calycine colleters in Odontadenia lutea (Apocynaceae - Apocynoideae - Odontadenieae): their structure and histochemistry

The structure and histochemistry of colleters found on the vegetative and floral apices of Odontadenia lutea are described. Colleters occur on vegetative apices starting at the fourth node, with 68 to 80 colleters being found at each node. Each leaf primordium has only one colleter of axillary origin, 3-5 intra-petiolar, and 12-16 inter-petiolar (intra-stipular). There are four types of colleters: standard, bipartite standard, sessile, and bipartite sessile. Colleters on the reproductive apices alternate with the sepals and are sessile, reduced sessile, tripartite laminar sessile, or asymmetrical. All of the colleters have a central nucleus of parenchymatous cells covered by a palisade uniseriate secretory epidermis and a thin cuticle. Secretory idioblasts were observed in the parenchymatous axis. Vascularization was observed only in standard axillary and laminar colleters. Crystals were observed in the parenchyma of the axillary colleter. Histochemical tests demonstrated that there was no rupturing or distension of the cuticle during the secretion process. Mucilage was identified using the PAS reaction as well as by Mayer's reagent and Ruthenium red staining. The calycine colleters had two distinct secretory phases, the first synthesizing mucilage and the second producing phenolic compounds.

Structure and function of the selectin ligand PSGL-1

P-selectin glycoprotein ligand-1 (PSGL-1) is a dimeric mucin-like 120-kDa glycoprotein on leukocyte surfaces that binds to P- and L-selectin and promotes cell adhesion in the inflammatory response. The extreme amino terminal extracellular domain of PSGL-1 is critical for these interactions, based on site-directed mutagenesis, blocking monoclonal antibodies, and biochemical analyses. The current hypothesis is that for high affinity interactions with P-selectin, PSGL-1 must contain O-glycans with a core-2 branched motif containing the sialyl Lewis x antigen (NeuAcE="Symbol">a2E="Symbol">®3Galß1E="Symbol">®4[FucE="Symbol">a1E="Symbol">®3]GlcNAcß1E="Symbol">®R). In addition, high affinity interactions require the co-expression of tyrosine sulfate on tyrosine residues near the critical O-glycan structure. This review addresses the biochemical evidence for this hypothesis and the evidence that PSGL-1 is an important in vivo ligand for cell adhesion.

Structure and function of the cystic fibrosis transmembrane conductance regulator

Cystic fibrosis (CF) is a lethal autosomal recessive genetic disease caused by mutations in the CF transmembrane conductance regulator (CFTR). Mutations in the CFTR gene may result in a defective processing of its protein and alter the function and regulation of this channel. Mutations are associated with different symptoms, including pancreatic insufficiency, bile duct obstruction, infertility in males, high sweat Cl-, intestinal obstruction, nasal polyp formation, chronic sinusitis, mucus dehydration, and chronic Pseudomonas aeruginosa and Staphylococcus aureus lung infection, responsible for 90% of the mortality of CF patients. The gene responsible for the cellular defect in CF was cloned in 1989 and its protein product CFTR is activated by an increase of intracellular cAMP. The CFTR contains two membrane domains, each with six transmembrane domain segments, two nucleotide-binding domains (NBDs), and a cytoplasmic domain. In this review we discuss the studies that have correlated the role of each CFTR domain in the protein function as a chloride channel and as a regulator of the outwardly rectifying Cl- channels (ORCCs).

Effect of race, genetic population structure, and genetic models in two-locus association studies: clustering of functional renin-angiotensin system gene variants in hypertension association studies

Previous genetic association studies have overlooked the potential for biased results when analyzing different population structures in ethnically diverse populations. The purpose of the present study was to quantify this bias in two-locus association studies conducted on an admixtured urban population. We studied the genetic structure distribution of angiotensin-converting enzyme insertion/deletion (ACE I/D) and angiotensinogen methionine/threonine (M/T) polymorphisms in 382 subjects from three subgroups in a highly admixtured urban population. Group I included 150 white subjects; group II, 142 mulatto subjects, and group III, 90 black subjects. We conducted sample size simulation studies using these data in different genetic models of gene action and interaction and used genetic distance calculation algorithms to help determine the population structure for the studied loci. Our results showed a statistically different population structure distribution of both ACE I/D (P = 0.02, OR = 1.56, 95% CI = 1.05-2.33 for the D allele, white versus black subgroup) and angiotensinogen M/T polymorphism (P = 0.007, OR = 1.71, 95% CI = 1.14-2.58 for the T allele, white versus black subgroup). Different sample sizes are predicted to be determinant of the power to detect a given genotypic association with a particular phenotype when conducting two-locus association studies in admixtured populations. In addition, the postulated genetic model is also a major determinant of the power to detect any association in a given sample size. The present simulation study helped to demonstrate the complex interrelation among ethnicity, power of the association, and the postulated genetic model of action of a particular allele in the context of clustering studies. This information is essential for the correct planning and interpretation of future association studies conducted on this population.

Photic driving in the electroencephalogram of children and adolescents: harmonic structure and relation to the resting state

In order to identify latent bioelectrical oscillators, 15 normal subjects (aged 9-17 years, 8 males, 7 females) were subjected to intermittent photic stimulation. The EEG amplitude spectra corresponding to the 11 fixed frequencies of stimulation presented (3-24 Hz) were combined to form "profiles" of the driving reaction in the right occipital area. The driving response varied with frequency, and was demonstrable in 70-100% of cases (using as criterion peak amplitudes 20% larger than those of the neighbors). The strongest responses were observed at the frequency closest to the alpha peak of the resting EEG. A secondary profile maximum was in the theta band. In 10 subjects, this maximum exceeded half the alpha peak (with an average of 72.4% of the alpha peak), while in the resting spectra, theta amplitudes were much lower than the alpha maxima. This responsiveness in theta activity seems to be characteristic of prepubertal and pubertal subjects. The profiles and resting EEG spectra showed a highly significant Pearson's correlation, with the peak in the theta band of the profiles being the main difference observed between them. The correlation coefficient was significantly correlated with the ratio of the maxima in the theta and alpha bands (R = -0.77, P<0.001). The correlation coefficient between profile and resting spectrum may be a useful indicator in screening methods used to reveal latent cerebral oscillators. Profiles for the second and third harmonics were correlated with those of the first harmonic (fundamental frequency), when considering the corresponding EEG frequencies. Peak frequencies in all three profiles were close to those of the individual's background alpha rhythm, and peak amplitudes in higher harmonics were not much lower than those of the fundamental frequency (mean values of 84 and 63%, for second and third harmonics, respectively).

Insights into the role of hydration in protein structure and stability obtained through hydrostatic pressure studies

A thorough understanding of protein structure and stability requires that we elucidate the molecular basis for the effects of both temperature and pressure on protein conformational transitions. While temperature effects are relatively well understood and the change in heat capacity upon unfolding has been reasonably well parameterized, the state of understanding of pressure effects is much less advanced. Ultimately, a quantitative parameterization of the volume changes (at the basis of pressure effects) accompanying protein conformational transitions will be required. The present report introduces a qualitative hypothesis based on available model compound data for the molecular basis of volume change upon protein unfolding and its dependence on temperature.

The effect of microgravity on tissue structure and function of rat testis

To explore whether an environment of weightlessness will cause damage to the reproductive system of animals, we used the tail-suspension model to simulate microgravity, and investigated the effect of microgravity on the tissue structure and function of the testis in sexually mature male rats. Forty-eight male Wistar rats weighing 200-250 g were randomly assigned to three groups (N = 16 each): control, tail traction, and tail suspension. After the rats were suspended for 7 or 14 days, morphological changes of testis were evaluated by histological and electron microscopic methods. The expression of HSP70, bax/bcl-2 and AR (androgen receptor) in testis was measured by immunohistochemistry. Obvious pathological lesions were present in the testis after the rats were suspended for 7 or 14 days. We detected overexpression of HSP70 and an increase of apoptotic cells, which may have contributed to the injury to the testis. The expression of AR, as an effector molecule in the testis, was significantly decreased in the suspended groups compared to control (P < 0.01). We also observed that, with a longer time of suspension, the aforementioned pathological damage became more serious and some pathological injury to the testis was irreversible. The results demonstrated that a short- or medium-term microgravity environment could lead to severe irreversible damage to the structure of rat testis.

Sensory evaluation and nutritional value of cakes prepared with whole flaxseed flour

The objective of this study was to evaluate the nutritional value, the oxidative stabilitiy, and consumer acceptance of cakes containing four different concentrations of flaxseed flour (5, 15, 30 and 45%) as partial replacement for wheat flour. The oxidative stability of polyunsaturated fatty acids was evaluated through the lipid peroxidation test (TBARS) in the flour and cakes. Linolenic acid was determined by gas chromatography as well as contents of protein, lipid, ash, and dietary fiber. Consumer acceptance was assessed using a structured hedonic scale of nine points. The oxidative stability of lipid flaxseeds was not affected by the heat treatment during flour processing and cake baking. Cakes made with 5, 15, and 30% of flaxseed flour, the most accepted by consumers, had dietary fiber levels ranging from 3.5 to 6.2 g and linolenic acid ranging from 445 to 2,500 mg.100 g-1 of the product. The cakes received claims of good and excellent source of dietary fiber and linolenic acid, respectively, both are bioactive compounds. The use of up to 30% of flaxseed flour in the preparation of cakes is a useful strategy to optimize the consumption of food rich in functional ingredients.

Effect of modified clays on the structure and functional properties of biofilms produced with zein

The purpose of this study was to evaluate changes in the structure and some functional properties of biofilms added with modified clays (Cloisite® 15A and Cloisite® 30B) prepared by the casting method. The analysis of the microstructure of the films, scanning electron microscopy (SEM), Optical microscopy (MO), and Infrared Spectroscopy (FTIR) indicated that the addition of clay in the films resulted in the formation of a heterogeneous microstructure, microcomposite or tactoid. Due to the formation of a microcomposite structure, functional properties of the films added with both clays such as opacity, solubility, and permeability to water vapor (PVA), were not better than those of the control film. Thus, it was concluded that although it is possible to produce a film added with modified clays using the casting method, it was not possible to obtain intercalation or exfoliation in a nanocomposite, which would result in improved functional properties.

Effect of incorporation of amaranth on the physical properties and nutritional value of cheese bread

At the present celiac disease has no known cure, and its only treatment is a strict lifelong adherence to a gluten-free diet. Cheese bread is a traditional Brazilian product and a safe option for celiacs. However, like other gluten-free breads, it has inherent low levels of fibers and minerals. The objective of this study was to evaluate the effect of incorporation of whole amaranth flour on the physical properties and nutritional value of cheese bread. Amaranth flour was incorporated at 10, 15, and 20% proportions in different formulations. The increasing amaranth levels darkened the product, reduced specific volume, and increased compression force. Ten percent amaranth-content cheese breads exhibited slight differences in physical properties compared with the controls. These results demonstrated the possibility of incorporating 10% of whole amaranth flour in the formulation of cheese bread resulting in a product with higher dietary fiber and iron contents and the same level of acceptance as that of the conventional formulation. The aim of this approach is to increase the availability of gluten-free bakery products with added nutritional value contributing to increase the variety of the diet of celiac patients.

Characterization and nutritional value of precooked products of kiwicha grains (Amaranthus caudatus)

AbstractKiwicha has significant nutritional characteristics. It is commonly used as a puffed product, but there is little research on the lamination process. In this paper, the physical, functional properties, chemical composition and acceptability of the precooked kiwicha grains were studied. Puffed (PK) and laminated kiwicha (LK) were made. Puffed amaranth (CPA) was used as a commercial reference standard. The raw grain (RG) showed a higher bulk density (0.85 g/ml) than in PK (0.18 g/ml) and LK (0.38 g/ml). Both products had a good expansion. The yellow index decreased in PK (50.92) and LK (45.87) respect to RG (65.64). The largest was CPA (58.54). In all the products, the precooking increased the index of absorption, solubility and swelling power. Also, they showed major pasting temperature, low peak viscosity and breakdown viscosity. In both formulated products, the content of total, soluble and insoluble dietary fibre decreased during the precooking process. The content of protein was optimal (between 14.57-14.59 g/100g). PK had high acceptability (5.84), preference (84.48%), purchase (38.79%) and consumption (43.96%) intention. The lowest was CPA. This work demonstrates that it’s feasible to make precooked products with good quality characteristics, chemical composition and acceptability for the development of new products.

Chemical composition and nutritive value of hot pepper seed (Capsicum annuum) grown in Northeast Region of China

Chemical composition and nutritive value of hot pepper seeds (Capsicum annuum) grown in Northeast Region of China were investigated. The proximate analysis showed that moisture, ash, crude fat, crude protein and total dietary fiber contents were 4.48, 4.94, 23.65, 21.29 and 38.76 g/100 g, respectively. The main amino acids were glutamic acid and aspartic acid (above 2 g/100 g), followed by histidine, phenylalanine, lysine, arginine, cysteine, leucine, tryptophan, serine, glycine, methionine, threonine and tyrosine (0.8-2 g/100 g). The contents of proline, alanine, valine and isoleucine were less than 0.8 g/100 g. The fatty acid profile showed that linoleic acid, palmitic acid, oleic acid, stearic acid and linolenic acid (above 0.55 g/100 g) as the most abundant fatty acids followed lauric acid, arachidic acid, gondoic acid and behenic acid (0.03-0.15 g/100 g). Analyses of mineral content indicated that the most abundant mineral was potassium, followed by magnesium, calcium, iron, zinc, sodium and manganese. The nutritional composition of hot pepper seeds suggested that they could be regarded as good sources of food ingredients and as new sources of edible oils.