A minor role of CD4+ T lymphocytes in the control of a primary infection of cattle with Mycoplasma mycoides subsp. mycoides

ABSTRACT: Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides, is an important livestock disease in Africa. The current control measures rely on a vaccine with limited efficacy and occasional severe side effects. Knowledge of the protective arms of immunity involved in this disease will be beneficial for the development of an improved vaccine. In previous studies on cattle infected with M. mycoides subsp. mycoides, a correlation was detected between the levels of mycoplasma-specific IFN-γ-secreting CD4+ T lymphocytes and reduced clinical signs. However, no cause and effect has been established, and the role of such cells and of protective responses acquired during a primary infection is not known.We investigated the role of CD4+ T lymphocytes in CBPP by comparing disease patterns and post mortem findings between CD4+ T cell depleted and non-depleted cattle. The depletion was carried out using several injections of BoCD4 specific murine monoclonal antibody on day 6 after experimental endotracheal infection with the strain Afadé. All cattle were monitored clinically daily and sacrificed 28-30 days post-infection. Statistically significant but small differences were observed in the mortality rate between the depleted and non-depleted animals. However, no differences in clinical parameters (fever, signs of respiratory distress) and pathological lesions were observed, despite elimination of CD4+ T cells for more than a week. The slightly higher mortality in the depleted group suggests a minor role of CD4+ T cells in control of CBPP.     

Climate trends and global crop production since 1980

Efforts to anticipate how climate change will affect future food availability can benefit from understanding the impacts of changes to date. We found that in the cropping regions and growing seasons of most countries, with the important exception of the United States, temperature trends from 1980 to 2008 exceeded one standard deviation of historic year-to-year variability. Models that link yields of the four largest commodity crops to weather indicate that global maize and wheat production declined by 3.8 and 5.5%, respectively, relative to a counterfactual without climate trends. For soybeans and rice, winners and losers largely balanced out. Climate trends were large enough in some countries to offset a significant portion of the increases in average yields that arose from technology, carbon dioxide fertilization, and other factors.     

Serotype distribution and production of muramidase-released protein, extracellular factor and suilysin by field strains of Streptococcus suis isolated in the United States

Streptococcus suis is an important swine pathogen and a zoonotic agent. Differences in virulence have been noted among the 33 described serotypes, serotype 2 being considered the most virulent. In this study, we aimed at assessing the serotype distribution and the production of virulence-associated markers by strains recovered from diseased pigs in the United States (U.S.). Results showed that among the 100 strains evaluated, serotype 3 (20% of the isolates) and serotype 2 (17%) were the most prevalent. We then investigated the presence in these isolates of the genes sly, epf and mrp, encoding the virulence-associated markers suilysin (SLY), extracellular factor (EF) and muramidase-released (MRP) protein, respectively. The effective production of the markers by the strains was also verified. Results showed that the presence of the gene did not always correlate with actual expression of the respective protein. In the case of MRP, this was due, in most cases, to frameshift mutations at the 5′ end of the gene resulting in premature stop codons. The most prevalent phenotypes among U.S. strains were MRP⁺EF⁻SLY⁻ (40%) and MRP⁻EF⁻SLY⁺ (35%). Serotype distribution greatly differed from that reported in several European countries, as did the production of virulence markers, particularly for serotype 2. On the other hand, our results for the U.S. S. suis isolates are similar to those reported for Canadian strains, suggesting a common status in North America.     

Atmospheric carbon injection linked to end-Triassic mass extinction

The end-Triassic mass extinction (~201.4 million years ago), marked by terrestrial ecosystem turnover and up to ~50% loss in marine biodiversity, has been attributed to intensified volcanic activity during the break-up of Pangaea. Here, we present compound-specific carbon-isotope data of long-chain n-alkanes derived from waxes of land plants, showing a ~8.5 per mil negative excursion, coincident with the extinction interval. These data indicate strong carbon-13 depletion of the end-Triassic atmosphere, within only 10,000 to 20,000 years. The magnitude and rate of this carbon-cycle disruption can be explained by the injection of at least ~12 × 10(3) gigatons of isotopically depleted carbon as methane into the atmosphere. Concurrent vegetation changes reflect strong warming and an enhanced hydrological cycle. Hence, end-Triassic events are robustly linked to methane-derived massive carbon release and associated climate change.     

Thyroid Dysplasia in Wistar Hannover GALAS Rats

Thyroid dysplasia was recognized in WistarHan GALAS rats and confirmed as a heritable congenital disorder. The gene or genes involved were not identified, but homozygous animals with thyroid dysplasia also exhibited stunted growth, had reduced pituitary gland growth hormone (GH) and were hypothyroid. Heterozygous animals exhibited thyroid dysplasia with normal thyroid hormonal homeostasis and no difference in the incidence of preneoplastic or neoplastic lesions in oncogenicity studies.     

Phenological phases of common beech (Fagus sylvatica L.) and their dependence on region and altitude in Southern Germany

Long-term observational data of the phenological network of the German Weather Service (DWD) were used to derive the altitudinal dependence of leaf unfolding (LU), leaf discolouration (LD) and the length of the vegetation period (LD-LU) of common beech (Fagus sylvatica L.) in different regions of Southern Germany. Depending on altitude, the vegetation period starts in Bavaria between the 2nd and 24th May with a delay of around 2 days per 100 m altitude increase (averaged over the last 30 years). In Southern Bavaria, LU starts a few days earlier as well as increases slightly faster into higher altitudes than in the northern regions. This can be explained by a more favourable supply of warmth and radiation in the south. The end of the vegetation period, defined here as the beginning of LD, showed no altitudinal dependence, which reflects an interaction of endogenous and exogenous factors as triggers for LD. In the Bavarian Forest region, altitudinal dependences are strongly influenced by sites which are affected by cold-air tailback (‘Kaltluftstau’) was obtained. Hence, phenological gradients should only be derived and applied above a phenological inversion zone. The calculated vertical gradients for LU can be used together with available observational data to estimate the beginning of the forest vegetation period of beech for different altitudes of Bavaria.     

Impact of late frost events on radial growth of common beech (Fagus sylvatica L.) in Southern Germany

Phenological, temperature, and tree-ring data were used in order to identify and quantify the impact of late frosts on common beech (Fagus sylvatica L.) at different altitudes in Southern Germany during the last century. For this intention, dendroecological investigations were made upon trees at the Meteorological Observatory Hohenpeißenberg as well as from seven stands in the Bavarian Forest and 17 stands at the northern fringe of the Alps. From these locations, a considerable number of severe growth minima in the tree-ring series could be related to late frost in the days of or immediately after leaf unfolding. The frequency of frost-related growth minima increases with altitude. In individual years, radial growth can be reduced by more than 90% (stand mean) in relation to the average growth of the ten previous years. Hence, late frosts are considered as important ecological events that strongly affect beech vitality and competitiveness especially at high altitudes. Evidence of significant impacts on radial growth by late frosts distinct before leaf unfolding or with temperatures above ?3°C was not found. Also, increasing frequency and intensity of late frosts during recent decades were not ascertained. Hence, the recently observed decreased vitality of common beech accompanied by growth depressions especially at high altitude sites in Central Europe cannot be explained as a consequence of late frost damage.