减轻玉米赤霉烯酮对精液质量的危害

众所周知,霉菌毒素既会危害母猪的繁殖性能,也会危害公猪的繁殖性能。生物转化是许多细胞所具有的解毒机制。将这一功能赋予一种饲料添加剂,有助于减轻玉米赤霉烯酮的毒性作用。     

Efficacy of vaccines against bacterial diseases in swine: what can we expect?

This paper discusses what can be expected with regard to efficacy of antibacterial vaccines used in swine, based on the present knowledge of pathogen–host interactions. First, vaccination against bacteria that mainly cause disease by production of exotoxins is considered. Vaccines containing the inactivated toxin or a non-toxic but antigenic recombinant protein derived from the exotoxin can be expected to provide protection against disease. The degree of protection induced by such vaccines varies, however, depending amongst other things on the pathogenesis of the disease. Vaccination against clostridial infections, Actinobacillus pleuropneumoniae infections, progressive atrophic rhinitis and enterotoxigenic Escherichia coli, is considered. The second part of the article deals with vaccination against extracellular bacteria. Protection against these bacteria is generally mediated by antibodies against their surface antigens and certain secreted antigens, but cellular immunity may also play a role. Efficacy of vaccines against swine erysipelas, Streptococcus suis infections, Mycoplasma hyopneumoniae infections and swine dysentery is discussed. Finally, vaccination against facultatively intracellular bacteria is considered. For protection against these bacteria cell-mediated immunity plays an important role, but antibodies may also be involved. It is generally accepted that live-attenuated vaccines are more suitable for induction of cell-mediated immunity than inactivated vaccines, although this also depends on the adjuvant used in the vaccine. As an example, vaccination against Salmonella enterica serotype Typhimurium is discussed.     

Ant species richness of fynbos and forest ecosystems in the southern Cape

The ant fauna in fynbos and forest habitats in the southern Cape are compared. There is no significant difference in ant species richness between the two undisturbed habitat types, and the only two species common to both are Acantholepis capensis and Camponotus maculatus. The degree of Hakea sericea infestation in the fynbos negatively affected ant species richness. Ant species richness in the Afromontane forest decreased from the drier to the wetter sites. The aggressive alien ant species, Iridomyrmex humilis, has not invaded natural areas to any great extent.     

Thinning golden delicious apples using ethephon sprays

In southern Tasmania ethephon sprays were applied at two stages of bloom and after bloom at concentrations from 350 to 1 400 ppm. At both the balloon blossom stage and 42 days after full bloom (AFB) 350 ppm ethephon caused satisfactory thinning of fruit by decreasing fruit set and increasing the number of fruits 70 mm or more in diameter. Higher concentrations of ethephon at these stages overthinned. At full bloom concentrations below 1 050 ppm ethephon did not remove significant numbers of fruit but both 1 050 and 1 400 ppm spray concentrations satisfactorily thinned the fruit. The spray of 1 400 ppm ethephon 42 days AFB significantly restricted fruit growth. Shoot length was reduced by all ethephon treatments and return bloom in the following spring was heavy in all thinned treatments. A mathematical model describing numbers of fruit set was developed and used to demonstrate a three-dimensional response surface to ethephon thinning sprays.     

Applying IUCN Red List criteria at a small regional level: A test case with butterflies in Flanders (north Belgium)

Red Lists are used to assess the extinction risk of species based on quantitative IUCN criteria. For the compilation of a new Red List of butterflies in Flanders (north Belgium), we collated ca 800,000 distribution records and applied the IUCN Red List criteria to this small region (ca 135,00 km²). We also explored the effect of spatial resolution on the outcome of the Red List assessment by alternatively using 1 × 1 km² and 5 × 5 km² grid cells for geographic range size and trend calculations. We determined conservation hot spots in Flanders based on the Red List status of the species composition in each grid cell. The new Red List classified 20 butterflies (out of 68 resident species) as Regionally Extinct, six as Critically Endangered, five as Endangered, seven as Vulnerable and seven as Near Threatened. The remaining 23 species were classified as Least Concern. Using coarse instead of fine grain grid cells would have classified ten species in a lower Red List category. Compared with the previous Red List, nine species were classified in a lower and 12 in a higher threat category. In total, 218 1 × 1 km² grid cells were considered as (very) high butterfly conservation priority sites. The application of the new IUCN criteria in a small region such as Flanders resulted in a Red List that offered challenging opportunities for the conservation of butterflies in particular and biodiversity in general.     

Observing others: multiple action representation in the frontal lobe

Observation of actions performed by others activates monkey ventral premotor cortex, where action meaning, but not object identity, is coded. In a functional MRI (fMRI) study, we investigated whether other monkey frontal areas respond to actions performed by others. Observation of a hand grasping objects activated four frontal areas: rostral F5 and areas 45B, 45A, and 46. Observation of an individual grasping an object also activated caudal F5, which indicates different degrees of action abstraction in F5. Observation of shapes activated area 45, but not premotor F5. Convergence of object and action information in area 45 may be important for full comprehension of actions.     

A diarylquinoline drug active on the ATP synthase of Mycobacterium tuberculosis

The incidence of tuberculosis has been increasing substantially on a worldwide basis over the past decade, but no tuberculosis-specific drugs have been discovered in 40 years. We identified a diarylquinoline, R207910, that potently inhibits both drug-sensitive and drug-resistant Mycobacterium tuberculosis in vitro (minimum inhibitory concentration 0.06 mug/ml). In mice, R207910 exceeded the bactericidal activities of isoniazid and rifampin by at least 1 log unit. Substitution of drugs included in the World Health Organization's first-line tuberculosis treatment regimen (rifampin, isoniazid, and pyrazinamide) with R207910 accelerated bactericidal activity, leading to complete culture conversion after 2 months of treatment in some combinations. A single dose of R207910 inhibited mycobacterial growth for 1 week. Plasma levels associated with efficacy in mice were well tolerated in healthy human volunteers. Mutants selected in vitro suggest that the drug targets the proton pump of adenosine triphosphate (ATP) synthase.