Hormonal control of fructose 2,6-bisphosphate concentration in the HT29 human colon adenocarcinoma cell line. Alpha 2-adrenergic agonists counteract effect of vasoactive intestinal peptide.

Vasoactive intestinal peptide (VIP) was found to cause a dose-dependent decrease in fructose 2,6-bisphosphatase concomitant with an increase in cyclic AMP in cultured HT29 cancer cells from human colon. The maximum effect was a 41% decrease obtained with 10 nM-VIP, and half-maximum effect was obtained with 0.75 nM-VIP. The effect of 2.5 nM-VIP was almost totally counteracted (i.e. fructose 2,6-bisphosphate concentration was restored) by either adrenaline (1 microM) or the alpha 2-adrenergic agonist UK-14304 (1 microM); the alpha 2-agonist clonidine (1 microM) was less efficient, since the VIP effect was decreased by 72% only. The adrenaline effect was totally antagonized by 1 microM-yohimbine. It is concluded that, in the HT29 cancer cells, the fructose 2,6-bisphosphate-producing system is sensitive to variations of cyclic AMP concentration and is under the dual control of VIP and alpha 2-adrenergic receptors.     

Activity of glycogen metabolizing enzymes in glucose deprived HT 29 adenocarcinoma cell-line

When deprived of glucose, the cultured HT 29 adenocarcinoma cells are able to mobilize their glycogen within 4 hours. Glycogen phosphorylase is strongly activated during the first hour of glucose starvation. Then, while the a/a + b ratio for phosphorylase is declining, glycogen synthase is partially converted into the a form; this conversion does occur although glycogen phosphorylase is far from being totally inactivated. After 4 hours, activity of both a and total forms of glycogen synthase decrease. Cell UDP-glucose and glucose-6-P levels are declining during the 24 hours period of glucose starvation. Cell ATP content decreases by only 50 percent over the same period of time.     

Activity of enzymes related to carbohydrate metabolism in the HT 29 colon adenocarcinoma cell line and tumor

Activity of several enzymes of the glycogen and carbohydrate metabolism is studied in HT 29 colon adenocarcinoma cell line and in HT 29 tumors developed in nude mice, by reference to the normal human colon mucosa. Activity of glycogen synthase, glycogen phosphorylase, pyruvate kinase, fructose-1,6-diphosphatase, glucose-6-phosphate dehydrogenase and lactate dehydrogenase is found to be increased in both the cultured cells and the tumors. It indicates that the biochemical strategy of malignant cells, due to the neoplastic transformation process, involves specific changes in the carbohydrate metabolism of tumor as well as in vitro growing correspondent cell line.     

Differentiations of Chitin Content and Surface Morphologies of Chitins Extracted from Male and Female Grasshopper Species

In this study, we used Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), thermogravimetric analysis (TGA), X-ray diffractometry (XRD), and scanning electron microscopy (SEM) to investigate chitin structure isolated from both sexes of four grasshopper species. FT-IR, EA, XRD, and TGA showed that the chitin was in the alpha form. With respect to gender, two main differences were observed. First, we observed that the quantity of chitin was greater in males than in females and the dry weight of chitin between species ranged from 4.71% to 11.84%. Second, using SEM, we observed that the male chitin surface structure contained 25 – 90nm wide nanofibers and 90 – 250 nm nanopores, while no pores or nanofibers were observed in the chitin surface structure of the majority of females (nanofibers were observed only in M. desertus females). In contrast, the elemental analysis, thermal properties, and crystalline index values for chitin were similar in males and females. Also, we carried out enzymatic digestion of the isolated chitins using commercial chitinase from Streptomyces griseus. We observed that there were no big differences in digestion rate of the chitins from both sexes and commercial chitin. The digestion rates were for grasshoppers’ chitins; 88.45–95.48% and for commercial chitin; 94.95%.     

Novel polymeric microspheres: Synthesis,enzyme immobilization,antimutagenic activity,and antimicrobial evaluation against pathogenic microorganisms

New polymeric microspheres containing azomethine ( 1a ‐ 1c and 2a ‐ 2c ) were synthesized by condensation to compare the enzymatic properties of the enzyme glucose oxidase (GOx) and to investigate antimutagenic and antimicrobial activities. The polymeric microspheres were characterized by elemental analysis, infrared spectra (FT‐IR), proton nuclear magnetic resonance spectra, thermal gravimetric analysis, and scanning electron microscopy analysis. The catalytic activity of the glucose oxidase enzyme follows Michaelis‐Menten kinetics. Influence of temperature, reusability, and storage capacity of the free and immobilized glucose oxidase enzyme were investigated. It is determined that immobilized enzymes exhibit good storage stability and reusability. After immobilization of GOx in polymeric supports, the thermal stability of the enzyme increased and the maximum reaction rate (V_max) decreased. The activity of the immobilized enzymes was preserved even after 5 months. The antibacterial and antifungal activity of the polymeric microspheres were evaluated by well‐diffusion method against some selected pathogenic microorganisms. The antimutagenic properties of all compounds were also examined against sodium azide in human lymphocyte cells by micronuclei and sister chromatid exchange tests.     

Native supported membranes on planar polymer supports and micro-particle supports

To bridge soft biological materials and hard inorganic materials is an interdisciplinary scientific challenge. Despite of experimental difficulties, the deposition of native biological membranes on supports is a straightforward strategy. This review provides an overview of advances in the fabrication and characterization of native biological membranes on planar polymer supports and micro-particles.     

Are we aware how contaminated our mobile phones with nosocomial pathogens?

Vibrio spp. is a pathogen rarely isolated in cancer patients, and in most cases it is associated with haematological diseases. Cutaneous manifestations of this organism are even rarer. We report a case of Non-O1 Vibrio cholerae inguinal skin and soft tissue infection presenting bullous skin lesions in a young type II diabetic patient with a penis squamous cell carcinoma having a seawater exposure history.