Histochemical detection of glycoproteins and glycosaminoglycans in the respiratory mucosa of albino rats during estrous cycle, pregnancy and puerperium

In this work we attempted to detect, with histochemical methods, the possible modifications in the mucus of the respiratory mucosa of albino female rats during estral cycle, pregnancy and puerperium. Based on its results, it was possible to conclude that: a--There were no modifications in the nature of the epithelial and supraepithelial mucus during the studied periods: b--The Alcian Blue staining from lamina propria is absent during pregnancy and present during puerperium.     

Metallothionein-like proteins in the blue crab Callinectes sapidus: Effect of water salinity and ions

The effect of water salinity and ions on metallothionein-like proteins (MTLP) concentration was evaluated in the blue crab Callinectes sapidus. MTLP concentration was measured in tissues (hepatopancreas and gills) of crabs acclimated to salinity 30 ppt and abruptly subjected to a hypo-osmotic shock (salinity 2 ppt). It was also measured in isolated gills (anterior and posterior) of crabs acclimated to salinity 30 ppt. Gills were perfused with and incubated in an isosmotic saline solution (ISS) or perfused with ISS and incubated in a hypo-osmotic saline solution (HSS). The effect of each single water ion on gill MTLP concentration was also analyzed in isolated and perfused gills through experiments of ion substitution in the incubation medium. In vivo, MTLP concentration was higher in hepatopancreas than in gills, being not affected by the hypo-osmotic shock. However, MTLP concentration in posterior and anterior gills significantly increased after 2 and 24 h of hypo-osmotic shock, respectively. In vitro, it was also increased when anterior and posterior gills were perfused with ISS and incubated in HSS. In isolated and perfused posterior gills, MTLP concentration was inversely correlated with the calcium concentration in the ISS used to incubate gills. Together, these findings indicate that an increased gill MTLP concentration in low salinity is an adaptive response of the blue crab C. sapidus to the hypo-osmotic stress. This response is mediated, at least in part, by the calcium concentration in the gill bath medium. The data also suggest that the trigger for this increase is purely branchial and not systemic.     

Cell cytoskeleton and tether extraction

We perform a detailed investigation of the force × deformation curve in tether extraction from 3T3 cells by optical tweezers. Contrary to conventional wisdom about tethers extracted from cells, we find that actin filaments are present within them, so that a revised theory of tether pulling from cells is called for. We also measure steady and maximum tether force values significantly higher than previously published ones for 3T3 cells. Possible explanations for these differences are investigated. Further experimental support of the theory of force barriers for membrane tube extension is obtained. The potential of studies on tether pulling force × deformation for retrieving information on membrane-cytoskeleton interaction is emphasized.     

Ovum pick up, in vitro embryo production, and pregnancy rates from a large-scale commercial program using Nelore cattle (Bos indicus) donors

The objective was to clarify in vitro production of bovine embryos in Brazil. Data from 656 ovum pick-up/in vitro production (OPU/IVP) procedures, performed on 317 Nelore (Bos indicus) donors, without hormone stimulation or control of ovarian follicular waves, were analysed. Donors were subjected to OPU from one to nine times (no specific schedule), with < 15 d between consecutive procedures. There were 20,848 oocytes, of which 15,747 (75.53%) were considered viable, 5,446 embryos were obtained, 5,398 embryos were immediately transferred, resulting in 1,974 pregnancies (36.57%) at Day 30 and 1,788 (33.12%) pregnancies at Day 60. The average number of total and viable oocytes produced per OPU session was (mean ± SEM) 30.84 ± 0.88 and 23.35 ± 0.7 (average of 8.1 ± 0.3 embryos and 3.0 ± 0.1 pregnancies per OPU-IVP procedure). Since oocyte production varied widely among donor, they were designated as very high, high, intermediate, and low, with 58.94 ± 2.04, 32.61 ± 0.50, 22.13 ± 0.50, and 10.26 ± 0.57 oocytes, respectively, produced by 78, 80, 79, and 80 donors. The number of viable oocytes recovered ranged from 0 to 128; since donors with numerous viable oocytes produced many viable embryos and pregnancies, oocyte production was useful for donor selection. However, there was no significant effect of the number of OPU sessions per donor on mean numbers of oocytes produced. In conclusion, we confirmed field reports of high oocyte production by some Nelore donors and demonstrated individual variation in oocyte yield, which was associated with embryo production and pregnancy rates.     

Water relations of Caatinga trees in the dry season

The Caatinga is one of the world's richest dry forests. This forest occurs only in Brazil, but is the least studied and protected Brazilian ecosystem. There are few reports about drought tolerance mechanisms in Caatinga trees. This work evaluates water relations of six adult species in the middle of the dry season to further understand water relations in this ecosystem, which will be important for future reforestation and management projects. Based on results, the trees were classified into four groups: (I), Mimosa caesalpiniifolia had low leaf water potential (Ψ_w) at predawn and no significant decrease at midday. Stomatal conductance (g_s) analyses indicates that plants have reached its lowest Ψ_w; (II), Caesalpinia pyramidalis and Auxemma oncocalyx had low Ψ_w at predawn and significant decrease at midday. For these species the recuperation of water status at night may have been sufficient for maintaining stomata open during the day; (III), Caesalpinia ferrea and Calliandra spinosa had relatively high Ψ_w at predawn and a significant decrease at midday. These species might maintain their water status similar to individuals of group II, but they might also have deeper root systems; and (IV), Tabebuia caraiba with the highest Ψ_w at predawn and no significant decrease at midday, possibly indicating a combination of good stomatal control of water loss and a deeper root system. Moreover, except for individuals of group I, both in species with lower and higher Ψ_w at predawn it was not observed strong inhibition of g_s.     

Chitobiase of planktonic crustaceans from South Atlantic coast (Southern Brazil): Characterization and influence of abiotic parameters on enzyme activity

Chitobiase is one of the enzymes involved in chitin degradation in nature. It is produced and released by a variety of organisms from bacteria to fish. In crustaceans, it is associated with digestive function and acts on the epidermis during the molting process. In the present study, the influence of water pH, temperature and salinity on maximum chitobiase activity (MCA), as well as the enzyme affinity (Km) for a substrate, the methylumbelliferyl N-acetyl-ß-d-glucosaminide (MUFNAG) was evaluated in the copepod Acartia tonsa. Km values for chitobiases of other crustaceans from the Patos Lagoon estuary and Cassino Beach (Southern Brazil) were also determined. For A. tonsa, MCA was observed at pH 5-6 and 30-35 °C. The range of pH was quite similar to that reported for other aquatic organisms. However, the range of temperature was lower than that previously reported. For salinity, no previous studies have considered the influence of this parameter on MCA. For A. tonsa, MCA was observed in freshwater, showing a significant linear decrease with increasing salinity. Considering that maximum copepod survival and growth rates are observed between 15 and 25 ppt, these findings suggest that the observed enzyme activity in this range of salinity (68 to 47% of that measured in freshwater) is not a limiting factor for A. tonsa growth. However, the extremely decreased enzyme activity observed in salinity 30 ppt (33% of that measured in freshwater) suggests that chitobiase activity might be one of the limiting factor for copepod growth at 30 ppt salinity or higher. Km values (μM) determined for organisms evaluated in the present study (copepod A. tonsa = 20.77; mysid Metamysidopsis elongata atlantica = 14.67; nauplii barnacle Balanus improvisus = 18.19; decapod zoea = 14.30; decapod megalopa = 24.77) were lower than those reported for other crustaceans from Northern Hemisphere. Also, they were much lower than those of organisms from different taxonomic groups like bacteria and fungi, but much higher than in protozoans and dinoflagelates. These findings suggest that chitobiase might be differentially evolved in each specific group of organism, and even within different ontogenetic stages of the same species, for a better adaptation to cope with its respective environmental needs.     

A concerted DNA methylation/histone methylation switch regulates rRNA gene dosage control and nucleolar dominance

Eukaryotes regulate the effective dosage of their ribosomal RNA (rRNA) genes, expressing fewer than half of the genes at any one time. Likewise, genetic hybrids displaying nucleolar dominance transcribe rRNA genes inherited from one parent but silence the other parental set. We show that rRNA gene dosage control and nucleolar dominance utilize a common mechanism. Central to the mechanism is an epigenetic switch in which concerted changes in promoter cytosine methylation density and specific histone modifications dictate the on and off states of the rRNA genes. A key component of the off switch is HDT1, a plant-specific histone deacetylase that localizes to the nucleolus and is required for H3 lysine 9 deacetylation and subsequent H3 lysine 9 methylation. Collectively, the data support a model in which cytosine methylation and histone deacetylation are each upstream of one another in a self-reinforcing repression cycle.     

Consensus statement understanding health and malnutrition through a systems approach: the ENOUGH program for early life

Nutrition research, like most biomedical disciplines, adopted and often uses experimental approaches based on Beadle and Tatum’s one gene—one polypeptide hypothesis, thereby reducing biological processes to single reactions or pathways. Systems thinking is needed to understand the complexity of health and disease processes requiring measurements of physiological processes, as well as environmental and social factors, which may alter the expression of genetic information. Analysis of physiological processes with omics technologies to assess systems’ responses has only become available over the past decade and remains costly. Studies of environmental and social conditions known to alter health are often not connected to biomedical research. While these facts are widely accepted, developing and conducting comprehensive research programs for health are often beyond financial and human resources of single research groups. We propose a new research program on essential nutrients for optimal underpinning of growth and health (ENOUGH) that will use systems approaches with more comprehensive measurements and biostatistical analysis of the many biological and environmental factors that influence undernutrition. Creating a knowledge base for nutrition and health is a necessary first step toward developing solutions targeted to different populations in diverse social and physical environments for the two billion undernourished people in developed and developing economies.     

Genetic associations with micronutrient levels identified in immune and gastrointestinal networks

The discovery of vitamins and clarification of their role in preventing frank essential nutrient deficiencies occurred in the early 1900s. Much vitamin research has understandably focused on public health and the effects of single nutrients to alleviate acute conditions. The physiological processes for maintaining health, however, are complex systems that depend upon interactions between multiple nutrients, environmental factors, and genetic makeup. To analyze the relationship between these factors and nutritional health, data were obtained from an observational, community-based participatory research program of children and teens (age 6–14) enrolled in a summer day camp in the Delta region of Arkansas. Assessments of erythrocyte S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH), plasma homocysteine (Hcy) and 6 organic micronutrients (retinol, 25-hydroxy vitamin D3, pyridoxal, thiamin, riboflavin, and vitamin E), and 1,129 plasma proteins were performed at 3 time points in each of 2 years. Genetic makeup was analyzed with 1 M SNP genotyping arrays, and nutrient status was assessed with 24-h dietary intake questionnaires. A pattern of metabolites (met_PC1) that included the ratio of erythrocyte SAM/SAH, Hcy, and 5 vitamins were identified by principal component analysis. Met_PC1 levels were significantly associated with (1) single-nucleotide polymorphisms, (2) levels of plasma proteins, and (3) multilocus genotypes coding for gastrointestinal and immune functions, as identified in a global network of metabolic/protein–protein interactions. Subsequent mining of data from curated pathway, network, and genome-wide association studies identified genetic and functional relationships that may be explained by gene–nutrient interactions. The systems nutrition strategy described here has thus associated a multivariate metabolite pattern in blood with genes involved in immune and gastrointestinal functions.

Electronic supplementary material

The online version of this article (doi:10.1007/s12263-014-0408-4) contains supplementary material, which is available to authorized users.