Detection of antibody and antigen in the milkweed bug,Oncopeltus fasciatus

Zusammenfassung Mit Hilfe der Fluoreszenzmarkierung von Proteinen und Ouchterlonys Methode wurde festgestellt, dass Insekten keine Immunität besitzen; Blutserum des Kaninchens blieb während 197 h im Hämolymph der Insekten.

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This research was supported in part by St. Louis University CRIC grants Nos. 64-03 and 65-03.     

A map of human genome sequence variation containing 1.42 million single nucleotide polymorphisms

We describe a map of 1.42 million single nucleotide polymorphisms (SNPs) distributed throughout the human genome, providing an average density on available sequence of one SNP every 1.9 kilobases. These SNPs were primarily discovered by two projects: The SNP Consortium and the analysis of clone overlaps by the International Human Genome Sequencing Consortium. The map integrates all publicly available SNPs with described genes and other genomic features. We estimate that 60,000 SNPs fall within exon (coding and untranslated regions), and 85% of exons are within 5 kb of the nearest SNP. Nucleotide diversity varies greatly across the genome, in a manner broadly consistent with a standard population genetic model of human history. This high-density SNP map provides a public resource for defining haplotype variation across the genome, and should help to identify biomedically important genes for diagnosis and therapy.     

Method of Stabilizing the Surface Energy of Fabrics Coated with Silicone

Silicone coatings have been used in this study. The method adopted was the liquid drop analysis on the coated fabrics. The contact angle between a liquid drop and the fabric surface was measured with two liquids continuously and recorded by a computer. The surface energy was calculated by means of Owens method. Kinetic measurement was adopted. The contact angle of liquids on the fabric coated silicone decreased with time was found. A compound solution DX has been found, so that the contact angle of the liquids on the fabric washed with DX becomes constant, and the surface energy of the fabric can be reduced to below 15 mJ/m2.     

Femtosecond X-ray protein nanocrystallography

X-ray crystallography provides the vast majority of macromolecular structures, but the success of the method relies on growing crystals of sufficient size. In conventional measurements, the necessary increase in X-ray dose to record data from crystals that are too small leads to extensive damage before a diffraction signal can be recorded. It is particularly challenging to obtain large, well-diffracting crystals of membrane proteins, for which fewer than 300 unique structures have been determined despite their importance in all living cells. Here we present a method for structure determination where single-crystal X-ray diffraction 'snapshots' are collected from a fully hydrated stream of nanocrystals using femtosecond pulses from a hard-X-ray free-electron laser, the Linac Coherent Light Source. We prove this concept with nanocrystals of photosystem I, one of the largest membrane protein complexes. More than 3,000,000 diffraction patterns were collected in this study, and a three-dimensional data set was assembled from individual photosystem I nanocrystals (～200?nm to 2?μm in size). We mitigate the problem of radiation damage in crystallography by using pulses briefer than the timescale of most damage processes. This offers a new approach to structure determination of macromolecules that do not yield crystals of sufficient size for studies using conventional radiation sources or are particularly sensitive to radiation damage.     

A salt-water reservoir as the source of a compositionally stratified plume on Enceladus

The discovery of a plume of water vapour and ice particles emerging from warm fractures ('tiger stripes') in Saturn's small, icy moon Enceladus raised the question of whether the plume emerges from a subsurface liquid source or from the decomposition of ice. Previous compositional analyses of particles injected by the plume into Saturn's diffuse E ring have already indicated the presence of liquid water, but the mechanisms driving the plume emission are still debated. Here we report an analysis of the composition of freshly ejected particles close to the sources. Salt-rich ice particles are found to dominate the total mass flux of ejected solids (more than 99 per cent) but they are depleted in the population escaping into Saturn's E ring. Ice grains containing organic compounds are found to be more abundant in dense parts of the plume. Whereas previous Cassini observations were compatible with a variety of plume formation mechanisms, these data eliminate or severely constrain non-liquid models and strongly imply that a salt-water reservoir with a large evaporating surface provides nearly all of the matter in the plume.     

Activation of cytolytic T lymphocyte and natural killer cell function through the T11 sheep erythrocyte binding protein

The T11 sheep erythrocyte binding glycoprotein [relative molecular mass (Mr)50,000(50K)] is expressed throughout human T-lymphocyte ontogeny and appears to play an important physiological role in T-cell activation. Thus, the treatment of T cells with certain monoclonal anti-T11 antibodies results in antigen-independent polyclonal T-cell activation as assessed by proliferation and lymphokine secretion. In addition, the majority of thymocytes that have not yet acquired the T3-Ti antigen/major histocompatibility complex (MHC) receptor can be activated to express interleukin-2 (IL-2) receptors through this T11 structure. We show here that the triggering of cytolytic T (Tc) cells via T11 causes an antigen-independent activation of the cytolytic mechanism as evidenced by the induction of nonspecific cytolytic activity. Furthermore, T11+T3-Ti- natural killer (NK) cell clones can also be induced to lyse NK-cell-resistant targets by treatment with anti-T11 monoclonal antibodies directed at defined T11 epitopes. These results indicate that T11 triggering can activate cytotoxic lymphocytes to express their functional programmes in the absence of specific antigen recognition via the T3-Ti complex and provide further evidence for the notion that certain NK cells and T lymphocytes are related.