Immune electrophoretic analysis of bovine milk and purified bovine milk protein fractions

Zusammenfassung Immunoelektrophoretisch liessen sich aus Kuhmilch mit Hilfe einiger Kaninchen-Anti-Milchseren mindestens 12 Immunpräzipitate nachweisen. Von diesen waren 6 Präzipitate serologisch mit Blutserumproteinen verwandt (u. a. Albumin und-Globulin). Ferner wurden Präparate von-Kasein,-Laktoglobulin und-Laktalbumin analysiert.     

Distribution of the herbicides 2,4,5-T and 2,4-D in pregnant mice. Accumulation in the yolk sac epithelium

Zusammenfassung Nach Injektion des Herbizids 2, 4, 5-T wurde bei der Maus im Dottersackepithel eine selektive Kumulation beobachtet. Bei früher Trächtigkeit passiert die Substanz die Placenta nicht. Der Wirkungsmechanismus dürfte mit dem des Trypanblaus identisch sein.     

In vivo imaging of germinal centres reveals a dynamic open structure

Germinal centres are specialized structures wherein B lymphocytes undergo clonal expansion, class switch recombination, antibody gene diversification and affinity maturation. Three to four antigen-specific B cells colonize a follicle to establish a germinal centre and become rapidly dividing germinal-centre centroblasts that give rise to dark zones. Centroblasts produce non-proliferating centrocytes that are thought to migrate to the light zone of the germinal centre, which is rich in antigen-trapping follicular dendritic cells and CD4+ T cells. It has been proposed that centrocytes are selected in the light zone on the basis of their ability to bind cognate antigen. However, there have been no studies of germinal-centre dynamics or the migratory behaviour of germinal-centre cells in vivo. Here we report the direct visualization of B cells in lymph node germinal centres by two-photon laser-scanning microscopy in mice. Nearly all antigen-specific B cells participating in a germinal-centre reaction were motile and physically restricted to the germinal centre but migrated bi-directionally between dark and light zones. Notably, follicular B cells were frequent visitors to the germinal-centre compartment, suggesting that all B cells scan antigen trapped in germinal centres. Consistent with this observation, we found that high-affinity antigen-specific B cells can be recruited to an ongoing germinal-centre reaction. We conclude that the open structure of germinal centres enhances competition and ensures that rare high-affinity B cells can participate in antibody responses.     

A new unique species of Mucroseius Lindquist, 1962 (Acari: Mesostigmata: Melicharidae) mites associated with sawyer beetles (Cerambycidae: Monochamus Dejean, 1821) from the Palaearctic Region

Adult females of a new species, Mucroseius insolitus sp. nov., are described from the metathoracic spiracular atria of the Black pine sawyer beetle Monochamus galloprovincialis (Coleoptera: Cerambycidae) from Asian Russia (Altai Republic and Tyumen Province). The new species differs from all congeners by the absence of the otherwise autapomorphic distal flangelike process (mucro) of the fixed chela. The genus Mucroseius is recorded for the first time in Russia, and its generic concept is reviewed.

urn:lsid:zoobank.org:act:AB3BDB6A-63C3-4970-A192-A3C539C48BA1     

The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis

Mycorrhizal symbioses--the union of roots and soil fungi--are universal in terrestrial ecosystems and may have been fundamental to land colonization by plants. Boreal, temperate and montane forests all depend on ectomycorrhizae. Identification of the primary factors that regulate symbiotic development and metabolic activity will therefore open the door to understanding the role of ectomycorrhizae in plant development and physiology, allowing the full ecological significance of this symbiosis to be explored. Here we report the genome sequence of the ectomycorrhizal basidiomycete Laccaria bicolor (Fig. 1) and highlight gene sets involved in rhizosphere colonization and symbiosis. This 65-megabase genome assembly contains approximately 20,000 predicted protein-encoding genes and a very large number of transposons and repeated sequences. We detected unexpected genomic features, most notably a battery of effector-type small secreted proteins (SSPs) with unknown function, several of which are only expressed in symbiotic tissues. The most highly expressed SSP accumulates in the proliferating hyphae colonizing the host root. The ectomycorrhizae-specific SSPs probably have a decisive role in the establishment of the symbiosis. The unexpected observation that the genome of L. bicolor lacks carbohydrate-active enzymes involved in degradation of plant cell walls, but maintains the ability to degrade non-plant cell wall polysaccharides, reveals the dual saprotrophic and biotrophic lifestyle of the mycorrhizal fungus that enables it to grow within both soil and living plant roots. The predicted gene inventory of the L. bicolor genome, therefore, points to previously unknown mechanisms of symbiosis operating in biotrophic mycorrhizal fungi. The availability of this genome provides an unparalleled opportunity to develop a deeper understanding of the processes by which symbionts interact with plants within their ecosystem to perform vital functions in the carbon and nitrogen cycles that are fundamental to sustainable plant productivity.     

Roadside foraging by kangaroo rats in a grazed short-grass prairie landscape

We used live-trapping and foraging experiments to describe use of roadside vegetation by kangaroo rats ( Dipodomys ordii ) in short-grass prairie in Colorado, and to determine whether this species' perception of predation risk differed between roadside habitats, where predators were expected to be most active, and locations 120 m into adjacent grazed pastures. Giving-up densities (GUDs) were measured in paired seed trays placed beneath saltbush ( Atriplex canescens ) shrubs and in the open, 3 m from shrubs along transects in roadside and pasture locations. Trials were conducted on nights with a partial (1st-quarter), full, and new moon to assess how intensity of risk affected microhabitat use. Kangaroo rats were much more abundant in areas with saltbush cover than in grazed prairie, and were 4–6 times more numerous along roadsides in saltbush areas than in other locations. On dark nights and in pasture locations, foraging rates of kangaroo rats were similar in shrub trays and open trays. The fewest seeds were removed (i.e., GUDs were highest), however, in open trays along roads on moonlit nights, suggesting that kangaroo rats recognized potential risks associated with roadsides on bright nights. The high numbers of kangaroo rats along roads suggest that benefits associated with these habitats (ease of digging, dust bathing, higher soil seed banks) exceed the costs associated with higher risk of mortality from predators and vehicles. Our results demonstrate how foraging decisions differ depending on the spatial and temporal contexts in which behaviors are measured, and underscore the potential value of less common habitats such as road margins for increasing landscape-scale diversity and wildlife habitat in grazed grasslands.     

Autoradiographic demonstration of uptake and accumulation of3H-6-hydroxydopamine in adrenergic nerves

Zusammenfassung Die Regenbogenhaut der Maus wurde in einer physiologischen Pufferlösung mit radioaktivem 6-Hydroxydopamin (³H-6-OH-DA) inkubiert. Mit Hilfe autoradiographischer und fluoreszenz-histochemischer Untersuchungen konnte gezeigt werden, dass³H-6-OH-DA in die adrenergischen Nervenfasern der Regenbogenhaut aufgenommen und gespeichert wird. Dieser Befund bringt die direkte Erklärung der durch 6-Hydroxydopamin induzierten Degeneration der adrenergen Fasern.