A comparison of three methods for the determination of available lysine in barley

The protein quality of barley was determined by the measurement of the protein efficiency ratio (PER). Available lysine in the same samples was determined chemically and by microbiological assay, and relationships were obtained between PER and either total or available lysine content.In the PER test, groundnut meal was found to be a suitable protein supplement to barley for the purpose of detecting differences in the protein quality of barley. The method was sufficiently sensitive to detect a reduction in protein quality of one variety as a result of micronization. Available lysine values obtained by the modified Tetrahymena method were significantly correlated (r = 0.99) with PER values; there was no significant correlation between total lysine content and the PER value.The available lysine values measured by the two chemical methods were higher than the Tetrahymena values. The Silcock method gave results better correlated (r = 0.93) with the Tetrahymena values than did the Carpenter method (r = 0.82). The results of chemical methods were not significantly related with PER values, but the methods ranked the barleys in an order similar to that obtained with the PER and Tetrahymena tests.     

A human NK cell activation/inhibition threshold allows small changes in the target cell surface phenotype to dramatically alter susceptibility to NK cells

NK cell activation is negatively regulated by the expression of target cell MHC class I molecules. We show that this relationship is nonlinear due to an NK cell activation/inhibition threshold. Ewing's sarcoma family tumor cell monolayers, which were highly susceptible to NK cells in vitro, developed a highly resistant phenotype when cultured as three-dimensional multicellular tumor spheroid structures. This suggested that tumor architecture is likely to influence the susceptibility to NK cells in vivo. Resistance of the multicellular tumor spheroid was associated with the increased expression of MHC class I molecules and greatly reduced NK cell activation, implying that a threshold of NK cell activation/inhibition had been crossed. Reducing MHC class I expression on Ewing's sarcoma family tumor monolayers did not alter their susceptibility to NK cells, whereas increased expression of MHC class I rendered them resistant and allowed the threshold point to be identified. This threshold, as defined by MHC class I expression, was predictive of the number of NK-resistant target cells within a population. A threshold permits modest changes in the target cell surface phenotype to profoundly alter the susceptibility to NK cells. Whereas this allows for the efficient detection of target cells, it also provides a route for pathogens and tumors to evade NK cell attack.     

Pegasys: software for executing and integrating analyses of biological sequences

Background  

We present Pegasys – a flexible, modular and customizable software system that facilitates the execution and data integration from heterogeneous biological sequence analysis tools.     

Poly(ethylene glycol)-carboxymethyl chitosan-based pH-responsive hydrogels: photo-induced synthesis, characterization, swelling, and in vitro evaluation as potential drug carriers

In this study, carboxymethyl chitosan was prepared, characterized, and then photo-induced graft copolymerized with poly(ethylene glycol) under a nitrogen atmosphere in aqueous solution using 2,2-dimethoxy-2-phenyl acetophenone (DMPA) as the photo-initiator. The grafting copolymerization process was confirmed and the resulting copolymers were characterized using differential scanning calorimetry (DSC), FTIR spectroscopy, 2D-X ray diffraction, and elemental analysis. The kinetics of the grafting reactions was also studied. Under the applied experimental conditions, the optimum grafting values were obtained at: CMCs = 0.2 g, PEGA = 249 mM, DMPA = 10.4 mM at a 2 h reaction time. Some of the resulting copolymers were selected and used in the presence of methylene bisacrylamide (MBA) as a crosslinking agent to develop pH-responsive hydrogel matrices. The swelling characteristics and the in vitro release profiles of 5-fluorouracil (5-FU), as a model drug, from the hydrogels were investigated. The results revealed that the hydrogel matrices developed in this study can be customized to act as good candidates in drug delivery systems.     

Synthesis and antitumor activity of indolylpyrimidines: marine natural product meridianin D analogues

Marine indole alkaloid meridianin D analogues have been synthesized starting from the appropriate 3-cyanoacetyl indole. A facile two-step conversion of 3-cyanoacetyl indole to the corresponding cyano meridianin D analogue by treatment with dimethylformamide-dimethylacetal and further cyclization of the resulting enaminonitrile with aminoguanidine is described. Then, alkaline hydrolysis of cyano meridianin D afforded the carboxylic acid analogue. The treatment of acid with 75% H(2)SO(4) afforded the desired 6-debromomeridianin D. Simply treatment of cyano meridianin D analogue with hydrazine hydrate afforded the amidrazone analogue. The biological evaluation indicated that cyano analogue showed good cytotoxic activity with IC(50) values of 0.85 and 2.65microg (against MCF7 and HeLa, respectively), but acid and amidrazone analogues showed high cytotoxicity with IC(50) values of 0.75 and 0.25microg, respectively (against MCF7).     

First report of Phytopythium vexans causing the “Avocado sadness” in Michoacan,Mexico

Mexico is the main producer, consumer and exporter of avocado in the world, being Michoacan the main producer state contributing more than 80% of the national production. There are phytopathogens that decimate the production causing the death of the tree. Root samples were collected in avocado trees that showed the characteristic symptomatology of the disease known as avocado sadness, the sampling was carried out in four of the main avocado producing towns, in the state of Michoacan, Mexico. The isolation consisted in sowing root tissue in Petri dishes with V8^®-PARPH culture medium, subsequently they were identified morphologically and for species level it was determined by molecular biology, with the PCR-ITS technique. Pathogenicity tests were performed in triplicate with avocado seedlings with more than six leaves. After 24 hours, the inoculated plants expressed decay in the apical part, after 120 hours the leaves showed yellowing and after 15 days there was a generalized wilt on the stem and leaves, re-isolating the phytopathogen Phytopythium vexans. This study confirms the first report of the oomycete P. vexans affecting avocado trees in the most important producing region of the Mexican Republic.     

First report of the presence of Acartia bispinosa Carl, 1907 (Copepoda,Calanoida) in a semi-enclosed Bay (Sharm El-Maya), northern Red Sea with some notes on its seasonal variation in abundance and body size

The calanoid copepod, Acartia bispinosa Carl, 1907, is reported for the first time in the Red Sea, where it is found to be an important copepod in the mesozooplankton community structure of the Sharm El-Maya Bay. Female and male are fully redescribed and illustrated of as the mouthparts of this species have never previously been described and figured. Acartia bispinosa was collected in the plankton samples throughout the year and showed two peaks of abundance, a pronounced one in April (4234 individuals m^-3), and second smaller peak during November (1784 individuals m^-3). The average total length of females varied between 1.32 and 1.53 mm at the end of June and January respectively. For males, the average total length fluctuated between 1.07 and 1.16 mm at end of June and March respectively. Temperature showed an inverse relationship with the body length (P > 0.001) and seemed to be one of the prime factors affecting the body length of both sexes.     

Labidocera boxshalli sp. nov., a new calanoid copepod (Crustacea; Pontellidae) from the Red Sea

A pontellid copepod, Labidocera boxshalli sp. nov., is described from the Egyptian coast of the northern Red Sea. This species is most readily distinguished from its congeners by the presence of a mid-dorsal process on the female genital double somite, the female fifth leg exopod terminating in two superimposed processes (the ventral of which is shorter), and by the elongated first exopodal segment of the male right fifth leg carrying a stout, blunt-tipped process and a small papilla laterally near the base of the thumb that bears one seta. The new species belongs to the L. detruncata species group, which is distributed mainly in the tropical/subtropical waters of the Indo-West Pacific.