Effect of Chitosan as Part of Biologically Active Feeding BiHit on Economically Useful Features of Bees

Applied Biochemistry and Microbiology - Currently biostimulants based on chitosan and its derivatives are increasingly used in veterinary medicine. Chitosan and its modifications have many...     

Delayed effect of prenatal exposure to hypoxia on the susceptibility of rats to electric seizures

We studied the delayed effects of prenatal exposure to hypoxia on the susceptibility of rats to seizures. The later was estimated using graded electroshock. The experiments were performed in two groups of 1.5-year-old male Wistar rats. The experimental group consisted of the animals that were exposed to hypoxia on day 14 of prenatal development, and the control group consisted of the animals that developed under the normal conditions. In the rats subjected to prenatal hypoxia, seizure episodes induced by weak currents in the range of 10–40 mA and their average duration were more pronounced as compared to the control animals.     

Dehydroepiandrosterone inhibits glucose flux through the pentose phosphate pathway in human and mouse endometrial stromal cells, preventing decidualization and implantation

Endometrial stromal cells (ESC) must undergo a hormone-driven differentiation to form decidual cells as a requirement of proper embryo implantation. Recent studies from our laboratory have demonstrated that decidualizing cells require glucose transporter 1 expression and an increase in glucose use to complete this step. The present study focuses on the glucose-dependent molecular and metabolic pathways, which are required by ESC for decidualization. Inhibition of glycolysis had no effect on decidualization. However, blockade of the pentose phosphate pathway (PPP) with pharmacologic inhibitors 6-aminonicotinamide or dehydroepiandrosterone (DHEA), and short hairpin RNA-mediated knockdown of glucose-6-phosphate dehydrogenase, the rate-limiting step in the PPP, both led to strong decreases in decidual marker expression in vitro and decreased decidualization in vivo. Additionally, the studies demonstrate that inhibition is due, at least in part, to ribose-5-phosphate depletion, because exogenous nucleoside administration restored decidualization in these cells. The finding that PPP inhibition prevents decidualization of ESC is novel and clinically important, because DHEA is an endogenous hormone produced by the adrenal glands and elevated in a high proportion of women who have polycystic ovary syndrome, the most common endocrinopathy in reproductive age women. Together, this data suggest a mechanistic link between increased DHEA levels, use of glucose via the PPP, and pregnancy loss.     

Influence of lowered temperature on the resistance and functional activity of the photosynthetic apparatus of wheat plants

The dynamics of cold resistance and the activity of the photosynthetic apparatus (PSA) of wheat germs at 4°C were studied. It was shown that in the first hours of cold, a certain functional readjustment to the changed conditions takes place in the plant organism. A decrease in the activity of the PSA and cessation of the linear growth of the leaf are registered at this stage along with an increase in resistance, as well as an increase in the coefficient of non-photochemical quenching of the fluorescence of chlorophyll. In one to four days, when resistance reaches its maximum, photosynthesis and the rate of electron transport are stabilized, the chlorophyll content in the lightcollecting complex increases, and the growth recommences. The final stage of adaptation (days 4–7) is characterized not only by the steady level of resistance but also by new functional organization of the PSA, which allows the plants to endure the lowered temperature successfully.     

Plant-made trastuzumab (herceptin) inhibits HER2/Neu+ cell proliferation and retards tumor growth

Background

Plant biotechnology provides a valuable contribution to global health, in part because it can decrease the cost of pharmaceutical products. Breast cancer can now be successfully treated by a humanized monoclonal antibody (mAb), trastuzumab (Herceptin). A course of treatment, however, is expensive and requires repeated administrations of the mAb. Here we used an Agrobacterium-mediated transient expression system to produce trastuzumab in plant cells.

Methodology/Principal Findings

We describe the cloning and expression of gene constructs in Nicotiana benthamiana plants using intron-optimized Tobacco mosaic virus- and Potato virus X-based vectors encoding, respectively, the heavy and light chains of trastuzumab. Full-size antibodies extracted and purified from plant tissues were tested for functionality and specificity by (i) binding to HER2/neu on the surface of a human mammary gland adenocarcinoma cell line, SK-BR-3, in fluorescence-activated cell sorting assay and (ii) testing the in vitro and in vivo inhibition of HER-2-expressing cancer cell proliferation. We show that plant-made trastuzumab (PMT) bound to the Her2/neu oncoprotein of SK-BR-3 cells and efficiently inhibited SK-BR-3 cell proliferation. Furthermore, mouse intraperitoneal PMT administration retarded the growth of xenografted tumors derived from human ovarian cancer SKOV3 Her2+ cells.

Conclusions/Significance

We conclude that PMT is active in suppression of cell proliferation and tumor growth.     

Purification and primary structure of two isoforms of arenicin, a novel antimicrobial peptide from marine polychaeta Arenicola marina

Two novel 21-residue antimicrobial peptides, arenicin-1 and arenicin-2, exhibiting activity against Gram-positive and Gram-negative bacteria and fungi, were purified from coelomocytes of marine polychaeta Arenicola marina (lugworm) by preparative gel electrophoresis and RP-HPLC. Molecular masses (2758.3 and 2772.3 Da) and complete amino acid sequences (RWCVYAYVRVRGVLVRYRRCW and RWCVYAYVRIRGVLVRYRRCW) were determined for each isoform. Each arenicin has one disulfide bond (Cys3-Cys20). The total RNA was isolated from the lugworm coelomocytes, RT-PCR and cloning were performed, and cDNA was sequenced. A 202-residue preproarenicin contains a putative signal peptide (25 amino acids) and a long prodomain. Arenicins have no structure similarity to any previously identified antimicrobial peptides.