Bacterial role in the decomposition of marine-derived material (penguin guano) in the terrestrial maritime Antarctic

Bacterial decomposition of Adélie Penguin (Pygoscelis adeliae) guano was followed during 42 days exposure in a rookery in Admiralty Bay, King George Island, South Shetland Islands, Antarctica. Bacterial abundance, both total counts (TC) determined by epifluorescence microscopy, and colony forming units (CFU) determined on nutrient media, was enhanced by an air temperature of between 7 and 11 °C, while temperatures above and below this negatively affected abundance. Optimal temperatures for guano decomposition ranged from 3 to 11 °C. Increasing wind velocity positively influenced photoautotrophic bacteria (TAC: total autotrophic bacteria count); photoautotrophs were enumerated during epifluorescence microscopy by their autofluorescence. Guano dry weight attained the lowest value of 74% of initial dry weight after 20 days in situ exposure. Changes in guano resulted from decomposition of the component fats, proteins, chitin, nitrogen and carbon, as well as of mineral recycling (Ca, P, Mg, and others). All transformations accompanied bacterial growth, with TC and CFU both attaining 10¹¹ cells g⁻¹ d wt of guano. Total bacterial biomass (TBB) increased from 594 μg C g⁻¹ dry weight in fresh guano, to 9101 μg C g⁻¹ dry weight after 42 days exposure in situ. Mean cell volume (MCV) also increased from 0.236 to 0.343 μm³. Photoautotrophic bacteria were numerically the smallest TC fraction throughout the incubation, with TAC to TC ratio ranging from 0.01 to 0.22%. Culturable bacteria abundance in guano increased dramatically from 0.28% of TC (in fresh guano) to 26% (3-h day), and 90% (42nd day) of TC. Within the total CFU population, copiotrophic bacteria were ca. two orders of magnitude more abundant than oligotrophic bacteria. Chitinolytic bacteria in guano were detected only late in the incubation; by 42 days, >40% of the initial chitin content remained. This material may comprise a significant fraction of the soil in the penguin rookery. Bacteria cultivated from the penguin guano displayed high morphophysiological diversity.     

Crops,weeds and gathered plants in the vicinity of the mediaeval Castle Kolno,near Brzeg,S-W Poland,and a morphometric approach for some taxa

Genetic Resources and Crop Evolution - In the present work, numerous species of useful and wild plants were identified in the archaeobotanical samples (moat deposit and two ceramic jugs) collected...     

Morus alba L. and Morus nigra L. Leaves as a Promising Food Source of Phenolic Compounds with Antioxidant Activity

Plant Foods for Human Nutrition - Bioactivity of mulberry has been widely described, but mostly related to its fruits, while studies with leaves are scarce. Herein, in this study leaves of two...     

Are oestrogen receptors and protein tyrosine kinases involved in phytoestrogen-modulated steroid secretion by porcine adrenocortical cells?

The phytoestrogens genistein and daidzein had been found to affect the function of some tissues via oestrogen receptors (ER). In addition, genistein, but not daidzein, is considered to be a protein tyrosine kinase (PTK) inhibitor. Thus, the involvement of oestrogen receptors and PTK in phytoestrogen action on adrenocortical porcine steroidogenesis was examined in this study. The aims of the experiment were to test the effects of (i) ICI 182, 780 (ICI), an ER antagonist, on genistein- and daidzein-modulated cortisol and androstenedione (A4) secretion by adrenocortical cells isolated during the luteal and follicular phases of the porcine oestrous cycle; (ii) tyrphostin AG 957 (TAG), a nonsteroidal PTK inhibitor, on cortisol and A4 secretion by the cells and (iii) the phase of the porcine oestrous cycle on the mechanism of phytoestrogen action. Adrenals were harvested during the luteal (n = 5 animals) and follicular (n = 5 animals) phases of the oestrous cycle from locally slaughtered crossbred gilts. The isolated adrenocortical cells were incubated for 8 h (37 °C, 95% air, 5% CO2) with genistein (5 or 10 μM) or daidzein (5 or 10 μM) in the presence or absence of ICI (0.5 μM) or TAG (5 or 10 μM). Genistein and daidzein inhibited cortisol secretion and stimulated A4 secretion by porcine adrenocortical cells harvested during both the luteal and follicular phases of the oestrous cycle. The ER antagonist ICI did not eliminate phytoestrogen-induced changes in steroidogenesis. In contrast to genistein, TAG reduced the secretion of A4 and did not affect cortisol secretion. There was no observable effect due to the phase of the cycle. It is suggested that the mechanism of genistein and daidzein action in the adrenocortical cells of pigs is independent of ER and PTK. It is possible that PTK are involved in A4 secretion by porcine adrenocortical cells.     

Two fiber genes of nearly equal lengths are a common and distinctive feature of Fowl adenovirus C members

The complete genome or the genome region containing the two fiber genes of two reference strains and one field isolate representing both serotypes of Fowl adenovirus C were sequenced. Two fiber genes were revealed in the genomes of all three isolates. Fiber-1 and fiber-2 genes of several Fowl adenovirus C isolates were sequenced as well. Both serotypes 4 and 10 have two fiber genes. The genome region containing the fiber gene was also sequenced for the reference strain of Fowl adenovirus B. Just one fiber gene was revealed in this strain. Predicted amino acid sequences were compared to already published fiber sequences of different adenovirus isolates and one amino acid substitution within fiber-2 was detected in all of the Fowl adenovirus C isolates that were isolated from chickens with hepatitis-hydropericardium syndrome in comparison to apathogenic isolates. Phylogenetic analyses provided insights about the evolution of fiber genes in avian adenoviruses and their genetic relationships.     

Diagnosis of osteopathy in cattle using bone biopsy

Seventy samples of bone bioptates from 70 cows were examined by the biochemical analysis and radiographically. By biochemical examination of bone bioptates taken from the tuber coxae we demonstrated the osteoporotic process in 87% of examined dairy cows, the osteomalacic process in 57% and the combined form, i.e. osteoporosis/osteomalacia in 51.4% of examined dairy cows. According to the distribution of findings in relation to the phases of reproduction cycle, the frequency of pathological findings was found to be highest in cows after calving. The examination of ash for the content of osteotrophic minerals, calcium and phosphorus, has demonstrated the physiological relation in 5.7% of dairy cows only, widened ratio in 87.2% and reduced one in 7.1% of dairy cows. By a comparison of the biochemical finding with the radiographic one we have revealed the difference, by 23% lower, in identification of pathological cases by the radiographic method. The method of radiographic examination of bone bioptates can be used as screening in the diagnostics of metabolic osteopathies.     

Nitrous oxide and methane emissions from long-term tillage under a continuous corn cropping system in Ohio

Nitrous oxide (N₂O) and methane (CH₄) emitted by anthropogenic activities have been linked to the observed and predicted climate change. Conservation tillage practices such as no-tillage (NT) have potential to increase C sequestration in agricultural soils but patterns of N₂O and CH₄ emissions associated with NT practices are variable. Thus, the objective of this study was to evaluate the effects of tillage practices on N₂O and CH₄ emissions in long-term continuous corn (Zea mays) plots. The study was conducted on continuous corn experimental plots established in 1962 on a Crosby silt loam (fine, mixed, mesic Aeric Ochraqualf) in Ohio. The experimental design consisted of NT, chisel till (CT) and moldboard plow till (MT) treatments arranged in a randomized block design with four replications. The N₂O and CH₄ fluxes were measured for 1-year at 2-week intervals during growing season and at 4-week intervals during the off season. Long-term NT practice significantly decreased soil bulk density (ρ_b) and increased total N concentration of the 0–15 cm layer compared to MT and CT. Generally, NT treatment contained higher soil moisture contents and lower soil temperatures in the surface soil than CT and MT during summer, spring and autumn. Average daily fluxes and annual N₂O emissions were more in MT (0.67 mg m⁻² d⁻¹ and 1.82 kg N ha⁻¹ year⁻¹) and CT (0.74 mg m⁻² d⁻¹ and 1.96 kg N ha⁻¹ year⁻¹) than NT (0.29 mg m⁻² d⁻¹ and 0.94 kg N ha⁻¹ year⁻¹). On average, NT was a sink for CH₄, oxidizing 0.32 kg CH₄-C ha⁻¹ year⁻¹, while MT and CT were sources of CH₄ emitting 2.76 and 2.27 kg CH₄-C ha⁻¹ year⁻¹, respectively. Lower N₂O emission and increased CH₄ oxidation in the NT practice are attributed to decrease in surface ρ_b, suggesting increased gaseous exchange. The N₂O flux was strongly correlated with precipitation, air and soil temperatures, but not with gravimetric moisture content. Data from this study suggested that adoption of long-term NT under continuous corn cropping system in the U.S. Corn Belt region may reduce GWP associated with N₂O and CH₄ emissions by approximately 50% compared to MT and CT management.