Molecular and allergenic characterization of recombinant tropomyosin from mud crab Scylla olivacea

Molecular Biology Reports - Tropomyosin is a major allergen in crustaceans, including mud crab species, but its molecular and allergenic properties in Scylla olivacea are not well known. Thus, this...     

Inhibition by L-valine and L-norleucine of 3-phenylpyruvate-induced insulin release

Insulin release induced by 3-phenylpyruvate in isolated rat pancreatic islets was inhibited by L-valine, L-norleucine or aminooxyacetate. The inhibitory effect of these three agents coincided with a lesser stimulation by 3-phenylpyruvate of 14CO2 output from islets prelabelled with L-[U-14C] glutamine. Conversely, 3-phenylpyruvate augmented the rate of conversion of L-valine to 2-ketoisovalerate and that of L-norleucine to 2-ketocaproate. However, 3-phenylpyruvate, which increased 2-ketoisovalerate oxidative decarboxylation, inhibited 14CO2 production by islets exposed to D, L-[1-14C] norleucine. These findings reveal that distinct nutrient secretagogues (e.g. 3-phenylpyruvate and L-norleucine), which are each able to stimulate insulin release, may act antagonistically upon the secretory process when used in combination. The present results also emphasize the relevance of both mitochondrial oxidation and intracellular transfer of reducing equivalents as determinants of the secretory response to such nutrients as 3-phenylpyruvate and norleucine.     

Bladder tissue characterization using probe‐based Raman spectroscopy: Evaluation of tissue heterogeneity and influence on the model prediction

Existing approaches for early‐stage bladder tumor diagnosis largely depend on invasive and time‐consuming procedures, resulting in hospitalization, bleeding, bladder perforation, infection and other health risks for the patient. The reduction of current risk factors, while maintaining or even improving the diagnostic precision, is an underlying factor in clinical instrumentation research. For example, for clinic surveillance of patients with a history of noninvasive bladder tumors real‐time tumor diagnosis can enable immediate laser‐based removal of tumors using flexible cystoscopes in the outpatient clinic. Therefore, novel diagnostic modalities are required that can provide real‐time in vivo tumor diagnosis. Raman spectroscopy provides biochemical information of tissue samples ex vivo and in vivo and without the need for complicated sample preparation and staining procedures. For the past decade there has been a rise in applications to diagnose and characterize early cancer in different organs, such as in head and neck, colon and stomach, but also different pathologies, for example, inflammation and atherosclerotic plaques. Bladder pathology has also been studied but only with little attention to aspects that can influence the diagnosis, such as tissue heterogeneity, data preprocessing and model development. The present study presents a clinical investigative study on bladder biopsies to characterize the tumor grading ex vivo, using a compact fiber probe‐based imaging Raman system, as a crucial step towards in vivo Raman endoscopy. Furthermore, this study presents an evaluation of the tissue heterogeneity of highly fluorescent bladder tissues, and the multivariate statistical analysis for discrimination between nontumor tissue, and low‐ and high‐grade tumor.     

The stimulus-secretion coupling of amino acid-induced insulin release metabolic interaction L-asparagine and L-leucine in pancreatic islets

1. Because L-asparagine augments insulin release evoked by L-leucine, the metabolism of these two amino acids was investigated in rat pancreatic islets. 2. L-Leucine inhibited the uptake and deamidation of L-asparagine, but failed to exert any obvious primary effect upon the further catabolism of aspartate derived from exogenous asparagine. 3. L-Asparagine augmented the oxidation of L-leucine, and effect possibly attributable to activaion of 2-ketoisocaproate dehydrogenase. 4. The association of L-asparagine and L-leucine exerted a sparing action on the utilization of endogenous amino acids, so that the integrated rate of nutrients oxidation was virtually identical in the sole presence of L-leucine and simultaneous presence of L-asparagine and L-leucine, respectively. 5. It is proposed that the enhancing action of L-asparagine upon insulin release evoked by L-leucine is attributable to an increased generation rate of cytosolic NADPH rather than any increase in nutrients oxidation.     

Selective Targeting of Tumorigenic Cancer Cell Lines by Microtubule Inhibitors

For anticancer drug therapy, it is critical to kill those cells with highest tumorigenic potential, even when they comprise a relatively small fraction of the overall tumor cell population. We have used the established NCI/DTP 60 cell line growth inhibition assay as a platform for exploring the relationship between chemical structure and growth inhibition in both tumorigenic and non-tumorigenic cancer cell lines. Using experimental measurements of “take rate” in ectopic implants as a proxy for tumorigenic potential, we identified eight chemical agents that appear to strongly and selectively inhibit the growth of the most tumorigenic cell lines. Biochemical assay data and structure-activity relationships indicate that these compounds act by inhibiting tubulin polymerization. Yet, their activity against tumorigenic cell lines is more selective than that of the other microtubule inhibitors in clinical use. Biochemical differences in the tubulin subunits that make up microtubules, or differences in the function of microtubules in mitotic spindle assembly or cell division may be associated with the selectivity of these compounds.     

Selective Divalent Cobalt Ions Detection Using Ag2O3-ZnO Nanocones by ICP-OES Method for Environmental Remediation

Here, we have synthesized Ag₂O₃-ZnO nanocones (NCs) by a wet-chemical route using reducing agents at low temperature. The structural, optical and morphological properties of Ag₂O₃-ZnO NCs were investigated by several conventional techniques such as powder XRD, XPS, FESEM, XEDS, FTIR and UV/vis. spectroscopy. The analytical parameters of prepared NCs were also calculated for a selective detection of divalent cobalt [Co(II)] prior to its determination by inductively coupled plasma-optical emission spectrometry (ICP-OES). The selectivity of NCs toward various metal ions, including Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Ni(II), and Zn(II) was studied. Results of the selectivity study demonstrated that Ag₂O₃-ZnO NC phase was the most selective towards Co(II) ion. The uptake capacity for Co(II) ion was experimentally calculated to be ∼76.69 mgg⁻¹. Moreover, adsorption isotherm data provided that the adsorption process was mainly monolayer on homogeneous adsorbent surfaces of Ag₂O₃-ZnO NCs. Kinetic study revealed that the adsorption of Co(II) on Ag₂O₃-ZnO NCs phase followed the pseudo-second-order kinetic model. In addition, thermodynamic results provided that the adsorption mechanism of Co(II) ions on Ag₂O₃-ZnO NCs was a spontaneous process and thermodynamically favorable. Finally, the proposed method was validated by applying it to real environmental water samples with reasonable results.     

Stimulus-secretion coupling of arginine-induced insulin release. Metabolism of L-arginine and L-ornithine in pancreatic islets

Exogenous L-arginine and L-ornithine rapidly accumulate in rat pancreatic islets. L-Arginine is converted to L-ornithine and urea. Endogenous or exogenous L-ornithine generates di- and polyamines, the putrescine turnover being faster than that of spermidine and spermine. However, the major pathway for L-ornithine metabolism consists of its transamination to L-glutamaldehyde and further conversion to L-glutamate. The amines and L-glutamate derived from exogenous L-ornithine are incorporated into islet proteins at the intervention of transglutaminase and cycloheximide-sensitive biosynthetic processes, respectively. These findings suggest the hypothesis that the insulinotropic action of L-arginine and L-ornithine could somehow be related to the metabolism of these cationic amino acids in islet cells.     

Positive Maternal Attitude to the Family Eating Together Decreases the Risk of Adolescent Overweight

Objectives: To determine whether maternal attitude towards the family regularly eating together and maternal report of how often the family eat together are associated with adolescent offspring overweight. Research Methods and Procedures: A cross‐sectional mother‐child‐linked analysis was carried out using 14‐year follow‐up data from a population‐based prospective birth cohort of 3795 children (52% males) who were participants in the Mater‐University study of pregnancy, Brisbane, Australia. Maternal reports on family eating pattern reported at age 14 were used. Results: The prevalence of overweight at age 14 was 24.1% (95% confidence interval (CI), 22.3, 26.1) for males and 27.1% (CI, 25.1, 29.2) for females. The majority of mothers (78%) reported that the family ate together at least once a day, but only 43% reported that they felt that family eating together was important. The offspring of women who felt that the family eating together was not important had increased odds of being overweight at age 14 (odds ratio, 1.27; 95% CI, 1.05, 1.53) in age‐ and sex‐adjusted models. Adjustment for potential confounding factors had no substantive effect on the association. There was no association between maternal reports of how often the family actually did eat together and overweight at age 14 in the offspring. Discussion: These findings suggest that maternal attitude towards family eating patterns, but not maternal report of how often the family do eat together, are associated with childhood overweight status. Maternal attitude towards family eating (as opposed to a report of actual frequency at one time‐point) may reflect broader maternal influences (beyond family eating pattern) on their child's diet and eating patterns over a long time course.     

Converting differential-equation models of biological systems to membrane computing

This paper presents a method to convert the deterministic, continuous representation of a biological system by ordinary differential equations into a non-deterministic, discrete membrane computation. The dynamics of the membrane computation is governed by rewrite rules operating at certain rates. That has the advantage of applying accurately to small systems, and to expressing rates of change that are determined locally, by region, but not necessary globally. Such spatial information augments the standard differentiable approach to provide a more realistic model. A biological case study of the ligand–receptor network of protein TGF-β is used to validate the effectiveness of the conversion method. It demonstrates the sense in which the behaviours and properties of the system are better preserved in the membrane computing model, suggesting that the proposed conversion method may prove useful for biological systems in particular.