Factors influencing variability of proteolytic genes and activities in arable soils

Microorganisms, capable of proteolysis, are widely distributed in soil but almost nothing is known about the abundance of genes related to protein degradation and the regulation of their activity in terrestrial ecosystems. Therefore, the aim of this study was: (1) to quantify two bacterial genes involved in protein degradation, (2) to investigate factors affecting the abundance of these genes, and (3) to relate this data to potential proteolytic activities. For this purpose, an arable field in southern Germany under integrated management was studied. The uniformly managed field showed pronounced soil heterogeneity with four different soil types. In April, July and October 2003, soil samples were taken from the four soil types at three different depths. We applied a real-time PCR assay for quantification of subtilisin (sub) and neutral metalloprotease (npr) genes, both encoding for extracellular proteases, as well as the 16S rRNA gene representing a rough estimate of the size of the bacterial populations. Potential proteolytic activity was measured using casein as a substrate. Both soil type and time of sampling influenced the size and activity of the bacterial protease genes under investigation. Total nitrogen and carbon availability was, beside soil texture, the main factor responsible for the observed changes in the abundance of proteolytic genes and potential proteolytic activity. Whereas a positive relationship was found between sub and npr gene copy numbers and the number of 16S rRNA gene copies in all cases, a positive relationship between sub and npr coding genes and potential proteolytic activity was only found for sandy soils. This indicates that sandy soils cannot stabilize proteolytic enzymes and the activity of npr and sub genes is strictly dependent on the presence of the corresponding genes. In contrast, in clay soils proteolytic activity was not correlated with the abundance of the genes analyzed, probably due to the stabilization of the proteolytic enzymes.     

Study of changes of properties in thermically and hydrothermically treated feeds. 2. N fractions in fermentation medium at the incubation of treated feeds under in vitro conditions

In the extensive experiments in vitro degradation ability of hydrothermically and thermically treated feeds have been studied. The feeds used were soybean meal, horse bean, alfalfa meal, field pea. The feeds have been treated at 90, 110 and 130 degrees C for 30, 60 and 90 min. The treated feeds have been tested both for microbial degradation ability due to rumen microflora and enzymatic degradation ability via pepsin and trypsin. The fact has been regarded as an important finding that the degradation ability of nitrogenous compounds had been restricted effectively by hydrothermic treatment that was manifested by low ammonia-N levels in fermentation medium (11.3; 8.8; 15.9 and 1.1% out of nitrogen contents in the different feeds). On the other hand improved protein enzymatic digestibility have been recorded in treated feeds as compared with native ones.     

Bacteria subsisting on antibiotics

Antibiotics are a crucial line of defense against bacterial infections. Nevertheless, several antibiotics are natural products of microorganisms that have as yet poorly appreciated ecological roles in the wider environment. We isolated hundreds of soil bacteria with the capacity to grow on antibiotics as a sole carbon source. Of 18 antibiotics tested, representing eight major classes of natural and synthetic origin, 13 to 17 supported the growth of clonal bacteria from each of 11 diverse soils. Bacteria subsisting on antibiotics are surprisingly phylogenetically diverse, and many are closely related to human pathogens. Furthermore, each antibiotic-consuming isolate was resistant to multiple antibiotics at clinically relevant concentrations. This phenomenon suggests that this unappreciated reservoir of antibiotic-resistance determinants can contribute to the increasing levels of multiple antibiotic resistance in pathogenic bacteria.     

Versuche zur Frage der Bodensanierung im Forstamt Waldsassen

1956 wurden vom Institut für Forstsamenkunde und Pflanzenzüchtung der Forstlichen Forschungsanstalt (Prof. Dr. E.Rohmehder) in Zusammenarbeit mit der Oberforstdirektion Regensburg Versuche zur Verbesserung geringer Kiefernstandorte im FA Waldsassen, Abt. VII 5 b, ?Archenohe“ angelegt. Im Jahre 1960 wurden diese Versuchsflächen dem Institut für Waldbau zur weiteren Betreuung übergeben. Eine erstmalige Aufnahme dieser Flächen erfolgte im April 1962. Es liegen für die beiden Versuchsflächen somit die ersten Ergebnisse vor; es ist beabsichtigt, weitere Veröffentlichungen folgen zu lassen.     

Structure of the Atmosphere of Venus up to 110 Kilometers: Preliminary Results from the Four Pioneer Venus Entry Probes

The four Pioneer Venus entry probes transmitted data of good quality on the structure of the atmosphere below the clouds. Contrast of the structure below an altitude of 50 kilometers at four widely separated locations was found to be no more than a few degrees Kelvin, with slightly warmer temperatures at 30 degrees south latitude than at 5 degrees or 60 degrees north. The atmosphere was stably stratified above 15 or 20 kilometers, indicating that the near-adiabatic state is maintained by the general circulation. The profiles move from near-adiabatic toward radiative equilibrium at altitudes above 40 kilometers. There appears to be a region of vertical convection above the dense cloud deck, which lies at 47.5 to 49 kilometers and at temperature levels near 360 K. The atmosphere is nearly isothermal around 100 kilometers (175 to 180 K) and appears to exhibit a sizable temperature wave between 60 and 70 kilometers. This is where the 4-day wind is believed to occur. The temperature wave may be related to some of the wavelike phenomena seen in Mariner 10 ultraviolet photographs.     

Kettle holes reflect the biogeochemical characteristics of their catchment area and the intensity of the element-specific input

Journal of Soils and Sediments - Kettle holes are small inland water bodies known to be dominated by terrigenous material; however, the processes and structures that drive the enrichment and...     

Large‐bodied fish migration and residency in a flood basin of the Sacramento River,California, USA

River–floodplain complexes represent some of the most variable and diverse habitats on earth, yet they are among our planet's most threatened ecosystems. Use of these habitats by large‐bodied fishes is especially poorly understood, particularly in temperate regions. To provide insight into the factors that affect floodplain assemblages and migration, we sampled large‐bodied fishes with a fyke trap for 7 years in the Yolo Bypass, the primary flood basin of the Sacramento River, California. We collected a total of 18,336 individual fish comprised of 27 species, only 41% of which were native. Year‐round resident species white catfish Ameiurus catus, channel catfish Ictalurus punctatus and common carp Cyprinus carpio (all alien species) were the most abundant and comprised 74% of the total catch. Splittail Pogonichthys macrolepidotus (3.8%), white sturgeon Acipenser transmontanus (2.3%) and Sacramento sucker Catostomus occidentalis (1.1%) were the primary native species. We found that seasonal variation in water temperature and flood stage were important factors affecting the fish assemblage structure and the presence of migratory species. American shad Alosa sapidissima, an alien species, showed highest abundance during the early summer upstream migration, when temperatures were warmer. For native species, the abundances of white sturgeon, splittail, Sacramento pikeminnow Ptychocheilus grandis and Sacramento sucker were all highest during flood pulses. While our results suggest that flow alone is not sufficient to control alien species, the strong linkage between native fish migration and flow pulses highlights the importance of river–floodplain connectivity for the conservation of native fishes.     

Study of virulence in field isolates of infectious pancreatic necrosis virus obtained from the northern part of Norway

In order to study the variety of infectious pancreatic necrosis virus (IPNV) strains involved in outbreaks of infectious pancreatic necrosis (IPN) in Atlantic salmon fish farms, samples were collected from 19 different outbreaks of IPN in the northern part of Norway. The main objective of this study was to examine whether IPNV isolates of different virulence were involved in the outbreaks and could explain the variable IPN protection observed in vaccinated post‐smolts in the field. Both the molecular basis of virulence of all field isolates and virulence expressed by mortality after bath challenge of unvaccinated post‐smolts with eight of the isolates were studied. Very little variation among the field isolates was detected when the 578‐bp variable region encoding the VP2 protein known to be involved in virulence was sequenced. The cumulative mortality after experimental challenge with field isolates genetically characterized as highly virulent was always high (40–56%), while the cumulative mortality of the same strains in vaccinated post‐smolts during the field outbreaks varied from 1 to 50%. Although the tested samples came from fish vaccinated with the same vaccine product, the protection against IPN varied. These results demonstrate that differences in virulence of the isolates were not the main reason for the variation in mortality in the field outbreaks. Most of the field isolates were of high virulence, which is shown in experimental challenges to be important for mortality, but clearly other factors that might affect the susceptibility of IPN also play an important role in the outcome of an IPNV infection.