Gibberellic acid—Binding proteins from pea stems

Summary The formation of complexes of gibberellic acid (GA₃) and proteins under in vitro conditions was studied. It was shown that labelled GA₃ binds to soluble cytoplasmic proteins, although a considerable amount of radioactivity remains in the pellet containing nuclei and cell debris. GA₃-protein complexes are excluded from Sephadex G-10 column with the void volume. They sediment in linear sucrose density gradients as three distinct peaks, having higher S values than bovine serum albumin, used as a marker. Soluble GA₃-protein complexes can be separated into four zones of radioactivity upon ion exchange chromatography on DEAE-Sephadex A-50 column, each of them eluting with a different KCl concentration. Agarose gel electrophoresis of GA₃-protein complexes reveals two zones of radioactivity at the anodic part of the electrophoretogram. After extraction of the complex with ethanol, more than 90% of radioactivity is found in the ethanolic phase, which indicates that the binding is not covalent. GA₄₊₇ and GA₁₃ decrease the binding of GA₃ to cytoplasmic proteins for 30%, suggesting that some common binding sites exist at the same binding proteins.Abbreviations BAP benzylaldenine - GA gibberellic acid - IAA indolyl-3-acetic acid - TSS tris-sucrose-salts     

Distribution of superoxide dismutase in the ground squirrel (Citellus citellus): effect of the hibernation and arousal

The activity of superoxide dismutase (SOD) was studied in the liver, kidney, interscapular brown adipose tissue (IBAT), lung, heart and spleen of the active and hibernating ground squirrel (Citellus citellus). One group was examined immediately after the arousal from the hibernation. A considerable activity of this enzyme was found in homogenates of all tissues studied except the lung. This activity was lower in the liver and lung of the ground squirrel than in the rat (P less than 0.01). In the other tissues studied the enzyme activity was about the same level in both animals. In the ground squirrel hibernation didn't produce the significant change in SOD activity, as compared with the active state, except in the spleen. Tested immediately after the arousal, SOD activity was significantly higher in all tissues studied except in the IBAT, as compared with the hibernating ones (P less than 0.01).     

Spatio-temporal pattern of the Chironomidae community: toward the use of non-biting midges in bioassessment programs

We employed the self-organizing map (SOM) method to investigate the spatio-temporal pattern of the Chironomidae community in the Southern Morava River basin (Serbia) and to examine to what extent the Chironomidae community is affected by environmental factors. Additionally, this study explores the problems of utilizing chironomids in bioassessment programs. The SOM analysis of the chironomid community data produced 3 groups of sites. The indicator species analysis presented indicator taxa for two groups. Twenty taxa (at species, species group and genus level), according to the Kruskal–Wallis test, showed the most pronounced differences among the temporal units. Out of 15 measured environmental parameters, one-way ANOVA pointed out that 10 significantly differ between the groups. Elevation had the most important influence on the chironomid community, also affecting other environmental parameters. According to our findings, the winter season and the periods with high water level are the main sources of natural variability. To avoid such variability and to successfully incorporate Chironomidae in bioassessment programs, we suggest exclusion of the arguable months from monitoring programs.     

The Influence of Enzymatic Hydrolysis on Adsorption and Interfacial Dilatational Properties of Pumpkin (<Emphasis Type="Italic">Cucurbita pepo</Emphasis>) Seed Protein Isolate

Pumpkin seed protein isolate, PSPI, was enzymatically hydrolysed by alcalase to obtain pumpkin seed protein hydrolysate, PSPH. Kinetics of PSPI and PSPH adsorption layer formation at oil–protein solution interface and interfacial dilatational properties of the layers were investigated by the drop profile analysis tensiometer (PAT) in order to determine the influence of enzimatic hydrolysis on the interfacial properties of pumpkin seed proteins. The properties were investigated at different protein solution concentrations (0.0008–0.8 g/100 mL), ionic strengths (0–0.5 mol/L NaCl), and at two acidic pH (3 and 5, where PSPI’s pI?=?5). It was found that both, PSPI and PSPH, contribute to an increase in the interfacial pressure, π, at the oil–protein solution interface and form the interfacial proteinaceous films. Dilatational elasticity, E’, of the interfacial films was found to be a few times higher than the dilatational viscosity, E”, regardless of the experimental conditions. The obtained diffusion rate and adsorption rate constants, k_diff and k_ads respectively, were higher for PSPH than for PSPI. k_diff was found to increase as protein concentration was increased, and to decrease as ionic strength was increased, for both PSPI and PSPH. At pI?=?5, PSPH showed an increased π and E’, as well as mitigated influence of ionic strength on k_ads when compared to PSPI.     

Induction of sucrose synthase in the phloem of phytoplasma infected maize

In this study, we have analyzed the expression of the low oxygen inducible sucrose synthase isozyme SH1 (SUS-SH1) in the phloem of maize (Zea mays L.) infected with maize bushy stunt phytoplasma. Immunolocalization and Western blot analysis revealed several fold induction of SUS-SH1 in companion cells of phytoplasma inhabited phloem of leaf sheaths and stems. The results imply higher rates of sucrose metabolism and intensified hypoxia in the phloem.     

Genetic interactions between a phospholipase A2 and the Rim101 pathway components in S. cerevisiae reveal a role for this pathway in response to changes in membrane composition and shape

Modulating composition and shape of biological membranes is an emerging mode of regulation of cellular processes. We investigated the global effects that such perturbations have on a model eukaryotic cell. Phospholipases A₂ (PLA₂s), enzymes that cleave one fatty acid molecule from membrane phospholipids, exert their biological activities through affecting both membrane composition and shape. We have conducted a genome-wide analysis of cellular effects of a PLA₂ in the yeast Saccharomyces cerevisiae as a model system. We demonstrate functional genetic and biochemical interactions between PLA₂ activity and the Rim101 signaling pathway in S. cerevisiae. Our results suggest that the composition and/or the shape of the endosomal membrane affect the Rim101 pathway. We describe a genetically and functionally related network, consisting of components of the Rim101 pathway and the prefoldin, retromer and SWR1 complexes, and predict its functional relation to PLA₂ activity in a model eukaryotic cell. This study provides a list of the players involved in the global response to changes in membrane composition and shape in a model eukaryotic cell, and further studies are needed to understand the precise molecular mechanisms connecting them.     

SARS-CoV-2 S glycoprotein binding to multiple host receptors enables cell entry and infection

Glycoconjugate Journal - The severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) infection displays a wide array of clinical manifestations. Although some risk factors for...     

Effects of progesterone and estradiol benzoate on glutathione dependent antioxidant enzyme activities in the brain of female rats.

The activities of glutathione dependent antioxidant enzymes were measured in subcellular fractions of whole brain homogenates prepared from ovariectomized (OVX) female rats, untreated or treated 2 h or 24 h prior to sacrifice with a single dose of 2 mg progesterone (P) or 5 micrograms estradiol benzoate (EB). Glutathione peroxidase (GSH-Px) activity was not changed following systemic administration of EB, but P increased GSH-Px in the brain of OVX rats 24 h after the treatment. The activity of glutathione reductase (GR) was suppressed by EB short time, only 2 h following treatment, whereas P increased the enzyme activity 24 h after treatment. On the other hand, the activities of catalase (CAT) and glutathione-S-transferase (GST) were not changed following systemic administration of EB or P. The present work was carried out to study the involvement of ovarian steroids, especially P, in the control of GSH-Px and GR activities, and our results suggest that oxidative stress in the brain of female rats may be modulated by the level of progesterone.     

Antimicrobial activity of Thymus longicaulis C. Presl essential oil against respiratory pathogens

Thymus longicaulis C. Presl is a small aromatic perennial herb used as a traditional remedy for cold, flu and cough. Composition of the essential oil of T. longicaulis from Croatia and its in vitro antimicrobial activity against the most common respiratory pathogens were evaluated. The yield of essential oil obtained by hydrodistillation from aerial plant parts was 1.2%. According to the GC-MS analysis, a total of forty one compounds (99%) were identified. Thymol (46.3%), ??-terpinene (16.2%), thymyl methyl ether (11.4%), and p-cymene (9.4%) were the main components. Antimicrobial activity of the essential oil against six clinically isolated bacterial and yeast strains was determined using standard disc agar diffusion method and microdilution broth assay. The essential oil exhibited antimicrobial activity towards all tested respiratory pathogens. The most sensitive strains were Haemophilus influenzae and Streptococcus pneumoniae(MIC=0.78 mg/mL), while Staphylococcus aureus was the most resistant (MIC>25.00 mg/mL). Our results indicate that T. longicaulis essential oil could be effective against clinically relevant respiratory pathogens which have the ability to develop resistance to antimicrobial drugs.