Localization of penultimate carbohydrate residues in zona pellucida and acrosomes by means of lectin cytochemistry and enzymatic treatments

Lectins from peanuts (PNA) and soy beans (SBA) bind terminal residues of galactose (Gal) and N-acetyl-galactosamine (GalNAc) respectively. Galactose oxidase oxidizes the hydroxyl group at C-6 of terminal Gal and GalNAc blocking the binding of PNA and SBA. Binding of these lectins to sugar residues is also severely limited by the existence of terminal residues of sialic acid. In the present study, lectin cytochemistry in combination with enzymatic treatments and quantitative analysis has been applied at light and electron microscopical levels to develop a simple methodology allowing the in situ discrimination between penultimate and terminal Gal/GalNAc residues. The areas selected for the demonstration of the method included rat zona pellucida and acrosomes of rat spermatids, which contain abundant glycoproteins with terminal Gal/GalNAc residues. Zona pellucida was labelled by LFA, PNA and SBA. After galactose oxidase treatment, terminal Gal/GalNAc residues are oxidized, and reactivity to PNA/SBA is abolished. The sequential application of galactose oxidase, neuraminidase and PNA/ SBA has the following effects: (i) oxidation of terminal Gal/GalNAc residues; (ii) elimination of terminal sialic acid residues rendering accessible to the lectins preterminal Gal/GalNAc residues; and (iii) binding of the lectins to the sugar residues. Acrosomes were reactive to PNA and SBA. No LFA reactivity was detected, thus indicating the absence of terminal sialic acid residues. Therefore, no labelling was observed after both galactose oxidase--PNA/SBA and galactose oxidase--neuraminidase--PNA/SBA sequences. In conclusion, the combined application of galactose oxidase, neuraminidase and PNA/SBA cytochemistry is a useful technique for the demonstration of penultimate carbohydrate residues with affinity for these lectins. This revised version was published online in November 2006 with corrections to the Cover Date.     

Costs and Epidemiological Changes of Chronic Diseases: Implications and Challenges for Health Systems

Background

The need to integrate economic and epidemiological aspects in the clinical perspective leads to a proposal for the analysis of health disparities and to an evaluation of the health services and of the new challenges which are now being faced by health system reforms in middle income countries.

Objective

To identify the epidemiological changes, the demand for health services and economic burden from chronic diseases (diabetes and hypertension) in a middle income county.

Methods

We conducted longitudinal analyses of costs and epidemiological changes for diabetes and hypertension in the Mexican health system. The study population included both the insured and uninsured populations. The cost-evaluation method was used, based on the instrumentation and consensus techniques. To estimate the epidemiological changes and financial consequences for 2014–2016, six models were constructed according to the Box-Jenkins technique, using confidence intervals of 95%, and the Box-Pierce test.

Results

Regarding epidemiological changes expected in both diseases for 2014 vs. 2016, an increase is expected, although results predict a greater increase for diabetes, 8–12% in all three studied institutions, (p < .05). Indeed, in the case of diabetes, the increase was 41469 cases for uninsured population (SSA) and 65737 for the insured population (IMSS and ISSSTE). On hypertension cases the increase was 38109 for uninsured vs 62895 for insured. Costs in US$ ranged from $699 to $748 for annual case management per patient in the case of diabetes, and from $485 to $622 in patients with hypertension. Comparing financial consequences of health services required by insured and uninsured populations, the greater increase (23%) will be for the insured population (p < .05). The financial requirements of both diseases will amount to 19.5% of the total budget for the uninsured and 12.5% for the insured population.

Conclusions

If the risk factors and the different health care models remain as they currently are, the economic impact of expected epidemiological changes on the social security system will be particularly strong. Another relevant challenge is the appearance of internal competition in the use and allocation of financial resources with programs for other chronic and infectious diseases.     

Studies on the role and mode of operation of the very-lysine-rich histone H1 (F1) in eukaryote chromatin. The conformation of histone H1.

Proton magnetic resonance, circular dichroism and other studies of whole and cleaved calf thymus histone H1 (formerly F1) reveal the presence of specific folded structures in the region approximately from residue 40--115. Ionic, hydrogen-bond and hydrophobic interactions all appear to contribute to the stability of the structure, which is predicted to contain alpha-helices in regions 42--55 and 58--75. No evidence was found for beta-structures, either inter or intramolecular, or for any structure formation outside the region 40--115. At 18 degrees C and a protein concentration of 2 mM the first-order exchange rate between random-coil and structured forms is slower than 80 s-1; at 40 degrees C the exchange rate is faster than 330 s-1.     

Edaphic Factors are a More Important Control on Surface Fine Roots than Stand Age in Secondary Tropical Dry Forests

Although there are generalized conceptual models that predict how above and belowground biomass increase during secondary succession after abandonment from agriculture, there are few data to test these models for fine roots (defined as ≤2 mm diameter) in tropical forests. We measured live and dead fine roots (0–10 cm depth) in 18 plots of regenerating tropical dry forest in Costa Rica that varied in age from 5 to 60 yrs, as well as in soil properties. We predicted that both stand age and soil fertility would affect fine roots, with greater values in older forests on low fertility soils. Across two sampling dates and locations, live fine roots varied from 0.35 to 3.53 Mg/ha and dead roots varied from 0.15 to 0.93 Mg/ha. Surprisingly, there was little evidence that surface fine roots varied between sampling dates or in relation to stand age. By contrast, total, live, and dead fine roots averaged across sampling dates within plots were negatively correlated with a multivariate index of soil fertility (Pearson correlations coefficients were ?0.64, ?0.58, and ?0.68, respectively; P < 0.01) and other individual edaphic variables including pH, silt, calcium, magnesium, nitrogen, and phosphorus. These results suggest that soil fertility is a more important determinant of fine roots than forest age in tropical dry forests in Costa Rica, and that one‐way these plant communities respond to low soil fertility is by increasing fine roots. Thus, simple conceptual models of forest responses to abandonment from agriculture may not be appropriate for surface fine roots.     

Increased susceptibility to Pseudomonas aeruginosa infection under hindlimb-unloading conditions.

It has been reported that spaceflight conditions alter the immune system and resistance to infection [Belay T, Aviles H, Vance M, Fountain K, and Sonnenfeld G. J Allergy Clin Immunol 170: 262-268, 2002; Hankins WR and Ziegelschmid JF. In: Biomedical Results of Apollo. Washington, DC: NASA, 1975, p. 43-81. (NASA Spec. Rep. SP-368)]. Ground-based models, including the hindlimb-unloading model, have become important tools for increasing understanding of how spaceflight conditions can influence physiology. The objective of the present study was to determine the effect of hindlimb unloading on the susceptibility of mice to Pseudomonas aeruginosa infection. Hindlimb-unloaded and control mice were subcutaneously infected with 1 LD50 of P. aeruginosa. Survival, bacterial organ load, and antibody and corticosterone levels were compared among the groups. Hindlimb unloading had detrimental effects for infected mice. Animals in the hindlimb-unloaded group, compared with controls, 1). showed significantly increased mortality and reduced time to death, 2). had increased levels of corticosterone, and 3). were much less able to clear bacteria from the organs. These results suggest that hindlimb unloading may induce the production of corticosterone, which may play a critical role in the modulation of the immune system leading to increased susceptibility to P. aeruginosa infection.     

Arl13b regulates ciliogenesis and the dynamic localization of Shh signaling proteins

Arl13b, a ciliary protein within the ADP-ribosylation factor family and Ras superfamily of GTPases, is required for ciliary structure but has poorly defined ciliary functions. In this paper, we further characterize the role of Arl13b in cilia by examining mutant cilia in vitro and determining the localization and dynamics of Arl13b within the cilium. Previously, we showed that mice lacking Arl13b have abnormal Sonic hedgehog (Shh) signaling; in this study, we show the dynamics of Shh signaling component localization to the cilium are disrupted in the absence of Arl13b. Significantly, we found Smoothened (Smo) is enriched in Arl13b-null cilia regardless of Shh pathway stimulation, indicating Arl13b regulates the ciliary entry of Smo. Furthermore, our analysis defines a role for Arl13b in regulating the distribution of Smo within the cilium. These results suggest that abnormal Shh signaling in Arl13b mutant embryos may result from defects in protein localization and distribution within the cilium.     

TranScout: prediction of gene expression regulatory proteins from their sequences

MOTIVATION: The advent of genomics yields thousands of reading frames in search of function. Identification of conserved functional motifs in protein sequences can be helpful for function prediction. RESULTS: A database and a classification of reported DNA-binding protein motifs has been designed. A program ('TranScout') has been developed for the detection and evaluation of conserved motifs in prokaryotic and eukaryotic sequences of proteins with a gene regulatory function. The efficiency of the program is shown in a benchmark against a database obtained from SWISS-PROT without the protein sequences used to train the program. All motifs were detected with a mean average sensitivity of 0.98 and a mean average specificity of 0.92. AVAILABILITY: The program is freely available for use on the internet at http://luz.uab.es/transcout/. The user can find additional information at this site.     

Ligand screening by exoproteolysis and mass spectrometry in combination with computer modelling

Here, we present a new approach for protein ligand screening based on the use of limited exoproteolysis coupled to MALDI-TOF mass spectrometry, combined with computational modelling and prediction of binding energies. As a test for this combined approach, we have screened a combinatorial library containing 8000 peptides (organized in 60 peptide samples) based on positional scanning format. This library is attached to a poly-Pro framework, and screened against the Abl-SH3 domain. The results obtained demonstrated the validity of the experimental and theoretical approaches in identifying better ligands and in rationalizing the changes in affinity. Exoproteolysis coupled to MALDI-TOF mass spectrometry could be used to screen complex libraries in a fast and efficient way.     

Catecholamines and in vitro growth of pathogenic bacteria: enhancement of growth varies greatly among bacterial species

The purpose of this study was to examine the effects of catecholamines on in vitro growth of a range of bacterial species, including anaerobes. Bacteria tested included: Porphyromonas gingivalis, Bacteriodes fragilis, Shigella boydii, Shigella sonnie, Enterobacter Sp, and Salmonella choleraesuis. The results of the current study indicated that supplementation of bacterial cultures in minimal medium with norepinephrine or epinephrine did not result in increased growth of bacteria. Positive controls involving treatment of Escherichia coli with catecholamines did result in increased growth of that bacterial species. The results of the present study extend previous observations that showed differential capability of catecholamines to enhance bacterial growth in vitro.