Oscillation Criteria for Some Higher Order Integrodynamic Equations on Timescales

We study the oscillation behavior for some higher order integrodynamic equations on timescales. We establish some new sufficient conditions guaranteeing that all solutions of theses equations are oscillatory. Some numerical examples in the continuous case are given to validate the theoretical results

Development of chitosan-glucose and chitosan-citric complexes edible coating to improve tomatoes post-harvest quality

 The effect of different shrimp chitosan molecular weights as well as shrimp chitosan complexes (chitosan-glucose and chitosan-citric) on the quality characteristics of the stored (at 7°C±2°C and 90% RH) tomato fruits (Lycopersicum esculentum) was investigated.  Coating tomatoes with high molecular weight chitosan (H.M.C.G) significantly improved firmness and weight loss.  The lowest weight loss was found in high molecular weight chitosan-glucose (H.M.C.G) treatment followed by the fruits coated with high molecular weight chitosan (HMC) and then uncoated tomato fruits.  Both molecular weights was clear on retarding the total acidity loss especially for stored tomato fruit coated with low molecular weight chitosan, while control tomatoes exhibited a larger reduction (p ≤ 0.05) in total acidity over storage.  Meanwhile, the increasing of cold storage time significantly (p ≥ 0.05) increased the pH in all uncoated and coated tomatoes.  Generally, no significant (P > 0.05) difference was observed in pH, titratable acidity and total soluble solids (T.S.S.) as well as sensory attributes among the tomato fruits coated with chitosan, chitosan citric and chitosan glucose.  Meanwhile, the fruits coated with low molecular weight chitosan had a higher (p ≥ 0.05) T.S.S. compared with that coated by the high molecular weight chitosan.   Keywords: chitosan, edible coating, tomatoes, firmness and weight loss

Purification of kappa (k)-carrageenase from locally isolated Cellulosimicrobium cellulans

Partial purification of the crude kappa (k)-carrageenase present in the culture filtrates of Cellulosimicrobium cellulans was carried out by fractional precipitation, using ammonium sulphate, acetone and ethanol individually. The highest recovered protein (37.08%) combined with enzyme activity was obtained with ammonium sulphate. The fraction precipitated by 90% ammonium sulphate was re-purified by anion exchange chromatography diethylaminoethyl (DEAE) cellulose, A-52 and 79 fractions were obtained. The loaded protein was separated into 4 peaks. The third protein peak was the major one which contained the most recovered enzyme activity (84.95%) from the eluted fractions. The collected fractions of this peak were subjected to further purification by re-chromatography on Sephadex G-100. The k-carrageenase activity was fractionated into 2 peaks. The first peak was the major one containing 95.622% of the total recovered activity. The pooled fractions of the major protein component showed a specific k-carrageenase activity of 46.22 U/mg protein, yielding about 4.6 fold purification of the crude enzyme preparation. Some properties of purified k-carrageenase obtained from cellusimicrobium cellulans cultures were studied. The optimum reaction temperature of the purified k-carrageenase was 30°C and the maximum activity occurred at a reaction pH of 6.Key words: Cellulosimicrobium cellulans, k-carrageenase, purification, sephadex G-100, diethylaminoethyl (DEAE) sephadex A-52

Purification and characterization of alginate lyase from locally isolated marine Pseudomonas stutzeri MSEA04

An alginate lyase with high specific enzyme activity was purified from Pseudomonas stutzeri MSEA04, isolated from marine brown algae. The alginate lyase was purified by precipitation with ammonium sulphate, acetone and ethanol individually. 70% ethanol fraction showed maximum specific activity (133.3 U/mg). This fraction was re-purified by anion exchange chromatography DEAE- Cellulose A-52. The loaded protein was separated into 3 peaks. The second protein peak was the major one which contained 48.2% of the total protein recovered and 79.4% of the total recovered activity. The collected fractions of this peak were subjected to further purification by re-chromatography on Sephadex G-100. Alginate lyase activity was fractionated in the Sephadex column into one major peak, and the specific activity of this fraction reached 116 U/mg. The optimal substrate concentration, pH and temperature for alginate lyase activity were 8 mg/ml, pH 7.5 and 37 °C, respectively. While, Km and Vmax values were 1.07 mg alginate/ ml and 128.2 U/mg protein, respectively. The enzyme was partially stable below 50 °C, and the activity of the enzyme was strongly enhanced by K+, and strongly inhibited by Ba+2, Cd+2, Fe+2 and Zn+2. The purified enzyme yielded a single band on SDS-PAGE with molecular weight (40.0 kDa)

Cell cultures of the Manila clam and their possible use in biomonitoring and species preservation

A huge progress has been achieved in mammalian in vitro technique. Instead, of the many trials to develop marine invertebrate cell cultures, only a few have obtained them and only from few tissues. Since in vitro cell culture of invertebrates could be very useful for many aspects of basic and applied science, in this work we investigate and describe the development of a technique for the establishment of cell cultures from gill, mantle and gonadic tissue of the Manila clam (Ruditapes philippinarum). We maintained viable cultures for up to 25 days. Culture viability and proliferation were tested with 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) and with trypan blue, while an antibody against the ATP-dependent RNA helicase VASA, a protein expressed in the germline, and in multipotent stem cells of some animals, was used to verify the presence of these cell types. Following the described protocol: 1) explant resulted the better source to obtain cell cultures, when compared to enzymatic dissociation; 2) cultures of suspended cells were viable for longer period than adherent cells; 3) cell cultures obtained from tissues sampled in September-October performed better compared to other periods of the year, regarding maintenance and growth; 4) the tissue from which we obtained longer-lived cell cultures was gonadic tissue, especially form samples that show more undifferentiated germ cells and more VASA-stained cells. This study describes the challenges concerning the development of in vitro culture techniques for aquatic invertebrates

Non-invasive index of liver fibrosis induced by alcohol, thioacetamide and schistosomal infection in mice

<p>Abstract</p> <p>Background</p> <p>Non invasive approaches will likely be increasing utilized to assess liver fibrosis. This work provides a new non invasive index to predict liver fibrosis induced in mice.</p> <p>Methods</p> <p>Fibrosis was generated by thioacetamide (TAA), chronic intake of ethanol, or infection with <it>S. mansoni </it>in 240 mice. Both progression and regression of fibrosis (after treatment with silymarin and/or praziquantel) were monitored. The following methods were employed: (i) The METAVIR system was utilized to grade and stage liver inflammation and fibosis; (ii) Determination of hepatic hydroxyproline and collagen; and (iii) Derivation of a new hepatic fibrosis index from the induced changes, and its prospective validation in a group of 70 mice.</p> <p>Results</p> <p>The index is composed of 4 serum variable including total proteins, γ-GT, bilirubin and reduced glutathione (GSH), measured in diseased, treated and normal mice. These parameters were highly correlated with both the histological stage and the grade. They were combined in a logarithmic formula, which non-invasively scores the severity of liver fibrosis through a range (0 to 2), starting with healthy liver (corresponding to stage 0) to advanced fibrosis (corresponding stage 3).Receiver operating characteristic curves (ROC) for the accuracy of the index to predict the histological stages demonstrated that the areas under the curve (AUC) were 0.954, 0.979 and 0.99 for index values corresponding to histological stages 1, 2 and 3, respectively. Also, the index was correlated with stage and grade, (0.947 and 0.859, respectively). The cut off values that cover the range between stages 0-1, 1-2 and 2-3 are 0.4, 1.12 and 1.79, respectively. The results in the validation group confirmed the accuracy of the test. The AUROC was 0.869 and there was good correlation with the stage of fibrosis and grade of inflammation.</p> <p>Conclusion</p> <p>The index fulfils the basic criteria of non-invasive marker of liver fibrosis since it is liver-specific, easy to implement, reliable, and inexpensive. It proved to be accurate in discriminating precirrhotic stages.</p

Effects of short term feeding of some marine microalgae on the microbial profile associated with Dicentrarchus labrax post larvae

AbstractThis study investigates the microbial profile and antimicrobial activity of four marine microalgae species, Tetraselmis chuii, Nannochloropsis salina, Isochrysis galbana and Chlorella salina used in aquaculture of Dicentrarchus labrax in the post larval stage to estimate which was the best algal species that could be used as a green water technique and achieving the maximum rate of growth and survival of D. labrax post larvae. The results represented a significant increase in the length and width of D. labrax at p<0.05 recorded in the case of enrichment with I. galbana followed by N. salina, and the most weight was recorded in the case of N. salina as compared with the control. Significant increase in percentage of survival of D. labrax was recorded in the case of C. salina and T. chuii (70% and 60.1%, respectively) as compared with the control (22%). The antibacterial activity (AU) of the different microalgal ethanolic extracts against fish indicator pathogens was determined. The results indicated that the ethanolic extracts of C. salina and T. chuii have the most positive records against the fish indicator pathogens (Escherichia coli, Pseudomonas aeruginosa, Vibrio damsela, Vibrio fluvialis and Aeromonas hydrophila). The current study was extended to determine the GC–MS of ethanolic extract of C. salina and T. chuii. The main constituents detected in the ethanolic extract were organic acids like hexadecanoic acid, octadecanoic acid, and an acyclic diterpene alcohol like phytol