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Number of results: 15
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Abstract

Prof. Andrzej Dziembowski of the PAS Institute of Biochemistry and Biophysics, laureate of this year’s Prize of the Foundation for Polish Science (FNP), talks about RNA-degrading enzymes, the role of yeast in studies that help humans, and two different types of scientists.
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Abstract

Lipolytic activity was assayed in samples of Antarctic krill frozen in different conditions and in its liquid digesta with synthetic (tributylglycerol, esters of 2-naphtol and fatty acids C3, C9 , C14 and C18 ) and natural (olive oil) substrates. It was testified that the lipolytic activity is several-fold higher in the crustaceans with high food intake than in those with an empty digestive tract. Krill lipases show higher activity against esters of unsaturated fatty acids that against analogous derivatives of saturated ones and 10-fold higher affinity tributylglycerol (Km = 1.12 mM). Their maximal activity is at pH 6.4 and 37°C. E. superba lipases preserve total activity up to 35°C for 45 minutes, and are completely inactivated at 55°C for 5 minutes. Prevailing part of lipolytic activity is present in krill cephalothorax, however, extracts from krill abdomen also display a marked activity. Krill lipases are probably resistant to an attack of crustacean's proteinases.
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Abstract

The influence of ambient solar UV-A or UV-B radiation on growth responses was investigated in three varieties of cotton (Gossypium hirsutum L.) after exclusion of solar UV-A/B radiation: JK-35, IH-63 and Khandwa-2. Cotton plants were grown from seeds in UV-exclusion chambers lined with selective UV filters to exclude either UV-B (280-315 nm) or UV-A/B (280-400 nm) from the solar spectrum under field conditions. Excluding UV-B and UV-A/B significantly increased plant height, leaf area and dry weight accumulation in all three varieties of cotton. The varieties differed considerably in their sensitivity to ambient UV-A/B. Khandwa-2 was most sensitive and JK-35 least sensitive to ambient solar UV. We monitored the activity of the antioxidant enzymes superoxide dismutase (SOD), ascorbic acid peroxidase (APX), glutathione reductase (GR) and guaiacol peroxidase (GPX), as well as the level of the antioxidant ascorbic acid (ASA), in primary leaves of the most UV-sensitive variety (Khandwa-2). The level of UV-B-absorbing substances was significantly decreased by exclusion of solar UV-B and UV-A/B. Exclusion of solar UV decreased the activity of all the antioxidant enzymes monitored and the level of ascorbic acid versus control plants (+UV-A/B) grown under filters transparent to solar UV. Reduction of the antioxidant defense after UV exclusion indicates that ambient solar UV exerts significant stress and induces some reactive oxygen species to accumulate, which in turn retards the growth and development of cotton plants. Ambient solar UV stresses cotton plants, shifting their metabolism towards defense against solar UV. Exclusion of solar UV eliminates the need for that defense and leads to enhancement of primary metabolism.
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Abstract

Cold−adapted marine bacteria producing extracellular hydrolytic enzymes are important for their industrial application and play a key role in degradation of particulate or ganic matter in their natural environment. In this work, members of a previously−obtained protease−producing bacterial collection isolated from different marine sources from Potter Cove (King George Island, South Shetlands) were taxonomically identified and screened for their ability to produce other economically relevant enzymes. Eighty−eight proteolytic bacterial isolates were grouped into 25 phylotypes based on their Amplified Ribosomal DNA Restriction Analysis profiles. The sequencing of the 16S rRNA genes from representative isolates of the phylotypes showed that the predominant culturable protease−producing bacteria belonged to the class Gammaproteobacteria and were affiliated to the genera Pseudomonas , Shewanella , Colwellia , and Pseudoalteromonas , the latter being the predominant group (64% of isolates). In addition, members of the classes Actinobacteria, Bacilli and Flavobacteria were found. Among the 88 isolates screened we detected producers of amylases (21), pectinases (67), cellulases (53), CM−cellulases (68), xylanases (55) and agarases (57). More than 85% of the isolates showed at least one of the extracellular enzymatic activities tested, with some of them producing up to six extracellular enzymes. Our results confirmed that using selective conditions to isolate producers of one extracellular enzyme activity increases the probability of recovering bacteria that will also produce additional extracellular enzymes. This finding establishes a starting point for future programs oriented to the prospecting for biomolecules in Antarctica.
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Abstract

The aim of this study was to determine the effect of carfentrazone-ethyl (CE) doses of 0.265, 5.280, 10.560, 21.180, 42.240 μg kg-1 soil DM on fungi, Acnomycetes, organotrophic bacteria, total oligotrophic bacteria and spore-forming oligotrophic bacteria, and on the activity of dehydrogenases, catalase, urease, alkaline phosphatase, acid phosphatase, arylsulfatase and β-glucosidase. Carfentrazone-ethyl had a stimulating effect on total oligotrophic bacteria and organotrophic bacteria, but it inhibited the growth of Azotobacter, fungi, spore-forming oligotrophic bacteria and Actinomycetes. The analyzed substance modified the structure of soil microbial communities, and it induced the most profound changes in fungi. The highest values of the colony development (CD) index and the eco-physiological (EP) index were observed in organotrophic bacteria. The optimal dose of carfentrazone-ethyl stimulated the activity of dehydrogenases, catalase, urease, alkaline phosphatase, acid phosphatase and β-glucosidase, but it had no effect on arylsulfatase. The highest doses of the analyzed substance inhibited the activity of dehydrogenases (reduction from 11.835 to 11.381 μmol TPF), urease (reduction from 0.545 to 0.500 mmol N-NH4) and arylosulfatase (reduction from 0.210 to 0.168 mmol PNP). Dehydrogenases were most resistant to CE, whereas acid phosphatase and arylsulfatase were least resistant to the analyzed compound
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Abstract

In our previous Genome-wise Association Study we found that Cystic Fibrosis Transmem- brane Conductance Regulator gene (CFTR) is a candidate gene for sperm motility in fresh semen of Holstein-Friesian bulls. Since in cows thawed semen is commonly used for the artificial insem- ination (AI) we have decided to find out whether functional polymorphism within CFTR gene coding sequence is associated with selected parameters of thawed sperm, including their motility evaluated by computer-assisted sperm analysis (CASA), the activity of three antioxidant enzymes: glutathione peroxidase (GPx) catalase (CAT), superoxide dismutase (SOD), ATP con- tent and integrity of sperm membranes. One hundred twenty Holstein Friesian bulls kept in uni- form environmental conditions (one AI company) were included in the study. Significant associ- ations between genotypes of missense mutation within exon 11 of the CFTR gene (Met468Leu) and the activity of antioxidant enzymes and sperm mitochondrial function were revealed. No effect of CFTR genotypes on sperm motility was observed. Significant differences in CAT and SOD activity were found between AA and TT homozygous individuals. Bulls with TT genotype had the lowest activity of both antioxidant enzymes. The same bulls also showed the lowest num- ber of sperm with active mitochondria. Our results demonstrate that missense mutation Met468Leu within CFTR gene is associated with antioxidant enzyme activity and mitochondrial function of bovine thawed sperm without affecting their motility.
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Abstract

Newcastle disease (ND) is a highly contagious and economically important disease in the poultry industry caused by avian avulavirus-1, historically known as Newcastle disease virus (NDV). Control of ND primarily relies on prophylactic vaccination of flocks, and many vaccines are available on the market, both conventional and more recently introduced new generation recombinant types. To assess the protection level achieved by vaccination ELISA tests are typically used, they also are to track an infection with field strains in non-vaccinated flocks. Special modifications of ELISA can be used as a screening tool to detect infection in flocks vaccinated with new generation vaccines. In this study, we have developed an ELISA test for the detection of antibodies against the nucleoprotein (NP) of NDV and for differentiation of chickens vaccinated with commercial and prototype in-house recombinant vector vaccines from those infected with field NDV strains. The NP gene of LaSota NDV strain expressed in a baculovirus vector was used as a coating antigen in the ELISA. The developed test was optimized, validated and compared to other serological tests. The sensitivity, specificity and accuracy of recombinant NP protein-based ELISA were respectively 96.1%, 96.3%, and 96.2%. Inter-rater (kappa) agreement between the NP-ELISA and the gold standard HI test was calculated to be 0.995. In our comparisons, commercially available ELISA tests revealed different specificities ranging from 95.5–100% and sensitivities at variance, ranging from 90.1 to 99.0%. A high level of maternally derived antibodies was measured in the serum of 1-day-old broilers in the NP-ELISA assay. These antibodies had disappeared and were undetected at 3, 5 and 6 weeks post-vaccination but birds became positive again at 2 weeks after control infection with a velogenic NDV strain. In SPF chickens, antibodies against NP protein were detected only after a challenge. The recombinant NP protein-based ELISA test is sensitive, specific and accurate when compared to the gold standard HI test and commercially available kits. Moreover, the method could be also used for the differentiation between vaccinated and infected birds.
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Abstract

In this study, selected heavy metals resistant heterotrophic bacteria isolated from soil samples at the Windmill Islands region, Wilkes Land (East Antarctica), were characterized. Phylogenetic analysis revealed affiliation of isolates to genera Bacillus , Lysinibacillus , Micrococcus and Stenotrophomonas . The strains were found to be psychrotolerant and halotolerant, able to tolerate up to 10% NaCl in the growth medium. The Minimum Inhibitory Concentration of the seven heavy metals Cr, Cu, Ni, Co, Cd, Zn, and Pb was deter − mined in solid media for each bacterial strain. Gram−positive Vi−2 strain and Gram−negative Vi−4 strain showed highest multiply heavy metals resistance, and Vi−3 and Vi−4 strains showed multi−antibiotic resistance to more than a half of the 13 used antibiotics. Plasmids were detected only in Gram−negative Vi−4 strain. The bacteria were able to produce different hydrolytic enzymes including industrially important proteases, xylanases, cellulases, and b −glucosidases. High heavy metals resistance of the Antarctic bacteria suggests their potential application for wastewater treatment in cold and temperate climates. Highly sensitive to Cd and Co ions Vi−1, Vi−5 and Vi−7 strains would be promising for developing biosensors to detect these most toxic heavy metals in environmental samples.
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Abstract

Plants adapt to extremely low temperatures in polar regions by maximizing their photosynthetic efficiency and accumulating cryoprotective and osmoprotective compounds. Flowering plants of the family Poaceae growing in the Arctic and in the Antarctic were investigated. Their responses to cold stress were analyzed under laboratory conditions. Samples were collected after 24 h and 48 h of cold treatment. Quantitative and qualitative changes of sugars are found among different species, but they can differ within a genus of the family Poaceae. The values of the investigated parameters in Poa annua differed considerably depending to the biogeographic origin of plants. At the beginning of the experiment, Antarctic plants were acclimatized in greenhouse characterized by significantly higher content of sugars, including storage reserves, sucrose and starch, but lower total protein content. After 24 h of exposure to cold stress, much smaller changes in the examined parameters were noted in Antarctic plants than in locally grown specimens. Total sugar content and sucrose, starch and glucose levels were nearly constant in P. annua, but they varied significantly. Those changes are responsible for the high adaptability of P. annua to survive and develop in highly unsupportive environments and colonize new regions.
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Abstract

We examined the effects of feeding by the polyphagous insect Coccus hesperidum on its host plant Nephrolepis biserrata under different intensities of infestation. As an effect of scale insect feeding there were significant changes in the values of parameters reflecting the state of cell membranes. N. biserrata plants reacted to the biotic stress by increasing guaiacol peroxidase activity and decreasing catalase activity. Our data show that these processes play key roles in plant tolerance mechanisms, here the fern’s response to insect feeding. The observed complex reaction of N. biserrata testifies to actively proceeding, complex and very often contrasting mechanisms triggered with the aim of neutralizing the effects of biotic stress and enabling normal cell functioning in plants attacked by scale insects
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Abstract

The paper addresses the effect of a compost prepared from tobacco wastes with an admixture of bark and straw on the enzymatic activity and certain chemical properties of a grey-brown podzolic soil amended with that compost. The study was conducted under the conditions of a pot experiment in which the soil material was collected from the surface horizon of the grey-brown podzolic soil. The effect of the application of the compost was compared with soil without such amendment. The test plant was maize cv. Kosmo 230. Fertilisation of the light soil with the compost studied caused changes in the enzymatic activity of the soil that were related both to the dose of the compost and to the kind of enzyme studied. With increase in the dose of the compost there was an increase in dehydrogenase activity (highest dose) and a significant decrease in the activity of acid phosphatase. Moreover, it was observed that tobacco compost was a significant source that enriched the light soil in organic matter, total nitrogen, and available forms of phosphorus, magnesium and potassium, which was evident in increased yields of maize grown as the test plant. Significant correlations were also demonstrated between a majority of the biochemical and chemical parameters, which indicates that those parameters characterise well the biological properties of a grey-brown podzolic soil amended with tobacco compost.
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Abstract

In this investigation, the effects of genistein (GEN) on the expression of steroidogenic genes such as steroidogenic acute regulatory protein (StAR), side-chain cleavage enzymes (P450scc) and cytochrome P450 aromatase (CYP19) were assessed. For this study, forty young female Sprague Dawley (SD) rats at aged 2-3 months (200±20 g) and forty aged female SD rats aged 10-12 months (490±20 g) were selected. Also, based on weight they were divided into a negative control group (NC), three different GEN dose groups, which received GEN of 15, 30, 60 mg/kg, and a positive control group (PC). The experiment lasted 30 days. Concentrations of serum hormones were determined by Enzyme-linked immunosorbent assay (ELISA). Gene and protein expressions of StAR, P450scc and CYP19 were determined by Real-Time PCR and western blot techniques. It was observed that 30-60 mg/kg GEN could increase the expression of androgen generating key enzymes in the young rat ovary. GEN also significantly increased progesterone and E2 levels in the serum of aged rats and reduced the levels of LH and FSH in the serum of both young and aged rats. Compared with young rats, the effect of GEN on the ovary of aged rats was stronger and a lower dose of GEN (15 mg/kg) showed an obvious effect on these indicators. GEN influenced both estrogen level and indicators associated with estrogen and androgen transformation processes, which indicates that GEN can impair the growth and maturation of the ovary.
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Abstract

Barley phylloplane is seriously colonized by Drechslera graminea, the causal agent of leaf stripe disease in the hos. The present study involved the elucidation of alterations induced in the protein content of the host due to Drechslera infection. Naturally growing barley plants were obtained from fields and Drechslera graminea was isolated and identified from diseased plants’ leaves. After identification and preparation of the pure culture, the pathogen was inoculated on plants grown under aseptic and controlled laboratory conditions. Changes in the total soluble cytoplasmic proteins and defense enzymes of the host such as polyphenol oxidase (PPO), peroxidase (POX), phenylalanine lyase (PAL) and tyrosine ammonia lyase (TAL) were observed up to 5 h after inoculation. The results demonstrated a significant effect of the pathogen on the cytoplasmic protein expression of the host as well as in its defense system.
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Abstract

Allium cepa var. agrogarum L. seedlings grown in nutrient solution were subjected to increasing concentrations of Cd2+ (0, 1, 10, 100 μM). Variation in tolerance to cadmium toxicity was studied based on chromosome aberrations, nucleoli structure and reconstruction of root tip cells, Cd accumulation and mineral metabolism, lipid peroxidation, and changes in the antioxidative defense system (SOD, CAT, POD) in leaves and roots of the seedlings. Cd induced chromosome aberrations including C-mitoses, chromosome bridges, chromosome fragments and chromosome stickiness. Cd induced the production of some particles of argyrophilic proteins scattered in the nuclei and even extruded from the nucleoli into the cytoplasm after a high Cd concentration or prolonged Cd stress, and nucleolar reconstruction was inhibited. In Cd2+-treated Allium cepa var. agrogarum plants the metal was largely restricted to the roots; very little of it was transported to aerial parts. Adding Cd2+ to the nutrient solution affected mineral metabolism. For example, at 100 μM Cd it reduced the levels of Mn, Cu and Zn in roots, bulbs and leaves. Malondialdehyde content in roots and leaves increased with treatment time and increased concentration of Cd. Antioxidant enzymes appear to play a key role in resistance to Cd under stress conditions.
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Abstract

Two fungal strains, isolated from Livingston Island, Antarctica (Penicillium commune 161, psychrotolerant and Aspergillus glaucus 363, mesophilic) were investigated for a relationship between growth temperature and oxidative stress response. Cultivation at temperatures below - (10 and 15°C and 10 and 20°C for P. commune and A. glaucus, respectively) and above (25°C and 30°C for P. commune and A. glaucus, respectively) the optimum caused significant difference in growth and glucose uptake in comparison with the control cultures. Enhanced level of reserve carbohydrates (glycogen and trehalose) was determined under cultivation at different temperatures from the optimal one. While the highest content of trehalose was found in the exponential phase, glycogen accumulation was observed in the stationary phase when growth conditions deteriorate. The growth at temperature below- and above-optimum caused strain-dependent changes in two antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). While SOD activity in the psychrotolerant strain increases with decreasing of growth temperature, the mesophilic A. glaucus demonstrated marked reduction of it at below- and above-optimal temperature. Decreasing trend of CAT activity was observed in both strains below the optimal temperature indicating a lack of antioxidant protection from this enzyme under the cold stress conditions.
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