Chitosan magnetic nanoparticles for drug delivery systems

The potential of magnetic nanoparticles (MNPs) in drug delivery systems (DDSs) is mainly related to its magnetic core and surface coating. These coatings can eliminate or minimize their aggregation under physiological conditions. Also, they can provide functional groups for bioconjugation to anticancer drugs and/or targeted ligands. Chitosan, as a derivative of chitin, is an attractive natural biopolymer from renewable resources with the presence of reactive amino and hydroxyl functional groups in its structure. Chitosan nanoparticles (NPs), due to their huge surface to volume ratio as compared to the chitosan in its bulk form, have outstanding physico-chemical, antimicrobial and biological properties. These unique properties make chitosan NPs a promising biopolymer for the application of DDSs. In this review, the current state and challenges for the application magnetic chitosan NPs in drug delivery systems were investigated. The present review also revisits the limitations and commercial impediments to provide insight for future works.     

Bacteria-Based Analysis of HIV-1 Vpu Channel Activity

HIV-1 Vpu is a small, single-span membrane protein with two attributed functions that increase the virus'' pathogenicity: degradation of CD4 and inactivation of BST-2. Vpu has also been shown to posses ion channel activity, yet no correlation has been found between this attribute and Vpu''s role in viral release. In order to gain further insight into the channel activity of Vpu we devised two bacteria-based assays that can examine this function in detail. In the first assay Vpu was over-expressed, such that it was deleterious to bacterial growth due to membrane permeabilization. In the second and more sensitive assay, the channel was expressed at low levels in K⁺ transport deficient bacteria. Consequently, Vpu expression enabled the bacteria to grow at otherwise non permissive low K⁺ concentrations. Hence, Vpu had the opposite impact on bacterial growth in the two assays: detrimental in the former and beneficial in the latter. Furthermore, we show that channel blockers also behave reciprocally in the two assays, promoting growth in the first assay and hindering it in the second assay. Taken together, we investigated Vpu''s channel activity in a rapid and quantitative approach that is amenable to high-throughput screening, in search of novel blockers.     

Biomass axial distribution in airlift bioreactor with yeast and plant cells

This study was aimed at determining the degree of biomass homogeneity in the various parts of an internal loop airlift bioreactor, thus verifying the assumption, often made in bioreactor studies, of a well-mixed liquid-biomass system. Following characterization of the hydrodynamics of the vessel with water, the axial biomass distribution in the riser and downcomer was determined for plant and yeast cell suspensions of 5.8, 8.5, and 12.5 g DW/L Phaseolus vulgaris and of 30 and 46 g DW/L Saccharomyces cerevisiae. The airlift bioreactor with a surface ratio A(D)/A(D) of 1.04 and aspect ratio of 4.95 was investigated under various aeration rates. The yeast cells were found to be distributed practically uniformly throughout the vessel at the aeration rates of 0.1-1.45 vvm. However, in the case of the denser and cluster-forming plant cells, a clear trend of a gradual bio-mass accumulation in the downcomer, a slightly lower but uniform biomass loading in the riser, and a slightly higher biomass concentration in the gas-liquid separator was observed at the lower aeration rates of 0.1-0.61 vvm. In the case of powderized calcium carbonate (55g/L) often used in fermentations of organic acids, a slight trend of a gradual accumulation of solids towards the bottom parts in both the downcomer and riser was observed. A better representative sampling location, in terms of solids and biomass loading, seems to be in the middle part of the vessel. It is suggested that airlift bioreactors with higher aspect ratios (>5) may be prone to a more significant inhomogeneity of solids (biomass and particles).     

Ejaculation Induced by the Activation of Crz Neurons Is Rewarding to Drosophila Males

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The effect of alfalfa saponins on growth and lysis of Physarum polycephalum

The prelytic events associated with the interaction of saponins with Physarum polycephalum membrane components were studied. It was found that alfalfa saponins form interaction products with membranal sterols, proteins and phospholipids. The interaction of saponins with proteins affect also certain membranal enzymic activities such as NADH oxidase and Malate dehydrogenase. It is suggested that although the interaction of the saponin with sterols is much more specific than with other membranal components, the lysis of plasmodia of P. polycephalum should be attributed to a concerted attack on the various membrane constituents. In continuation of these interactions, the changes of permeability of plasmodia membrane were expressed by increment of inorganic sodium ions and water influx, traced by lysis, while no efflux of ions was observed.Killed in action in the October War, October 22, 1973.     

The Central Nervous System as Target of Bacillus anthracis Toxin Independent Virulence in Rabbits and Guinea Pigs

Infection of the central nervous system is considered a complication of Anthrax and was reported in humans and non-human primates. Previously we have reported that Bacillus anthracis possesses a toxin-independent virulent trait that, like the toxins, is regulated by the major virulence regulator, AtxA, in the presence of pXO2. This toxin-independent lethal trait is exhibited in rabbits and Guinea pigs following significant bacteremia and organ dissemination. Various findings, including meningitis seen in humans and primates, suggested that the CNS is a possible target for this AtxA-mediated activity. In order to penetrate into the brain tissue, the bacteria have to overcome the barriers isolating the CNS from the blood stream. Taking a systematic genetic approach, we compared intracranial (IC) inoculation and IV/SC inoculation for the outcome of the infection in rabbits/GP, respectively. The outstanding difference between the two models is exhibited by the encapsulated strain VollumΔpXO1, which is lethal when injected IC, but asymptomatic when inoculated IV/SC. The findings demonstrate that there is an apparent bottleneck in the ability of mutants to penetrate into the brain. Any mutant carrying either pXO1 or pXO2 will kill the host upon IC injection, but only those carrying AtxA either on pXO1 or in the chromosome in the background of pXO2 can penetrate into the brain following peripheral inoculation. The findings were corroborated by histological examination by H&E staining and immunofluorescence of rabbits'' brains following IV and IC inoculations. These findings may have major implications on future research both on B. anthracis pathogenicity and on vaccine development.     

Experimental studies on population genetics of complement 3 (C3) and serum component transferin (Tf) in the population of Northern Bavaria]

Within a population sample concerning 2500 blood donors of Northern Bavaria, the population genetics of the Systems C3 and Tf have been investigated. The calculated gene frequencies are: C3S = 0,789; C3F = 0,2028; C3Var. = 0,0082; TfC = 0,9960; TfVar. = 0,0040. As a "new" variant C3F1,55 has been found.