Fluorescent pigments in corals are photoprotective

All reef-forming corals depend on the photosynthesis performed by their algal symbiont, and such corals are therefore restricted to the photic zone. The intensity of light in this zone declines over several orders of magnitude--from high and damaging levels at the surface to extreme shade conditions at the lower limit. The ability of corals to tolerate this range implies effective mechanisms for light acclimation and adaptation. Here we show that the fluorescent pigments (FPs) of corals provide a photobiological system for regulating the light environment of coral host tissue. Previous studies have suggested that under low light, FPs may enhance light availability. We now report that in excessive sunlight FPs are photoprotective; they achieve this by dissipating excess energy at wavelengths of low photosynthetic activity, as well as by reflecting of visible and infrared light by FP-containing chromatophores. We also show that FPs enhance the resistance to mass bleaching of corals during periods of heat stress, which has implications for the effect of environmental stress on the diversity of reef-building corals, such as enhanced survival of a broad range of corals allowing maintenance of habitat diversity.     

Reconstructing the early evolution of Fungi using a six-gene phylogeny

The ancestors of fungi are believed to be simple aquatic forms with flagellated spores, similar to members of the extant phylum Chytridiomycota (chytrids). Current classifications assume that chytrids form an early-diverging clade within the kingdom Fungi and imply a single loss of the spore flagellum, leading to the diversification of terrestrial fungi. Here we develop phylogenetic hypotheses for Fungi using data from six gene regions and nearly 200 species. Our results indicate that there may have been at least four independent losses of the flagellum in the kingdom Fungi. These losses of swimming spores coincided with the evolution of new mechanisms of spore dispersal, such as aerial dispersal in mycelial groups and polar tube eversion in the microsporidia (unicellular forms that lack mitochondria). The enigmatic microsporidia seem to be derived from an endoparasitic chytrid ancestor similar to Rozella allomycis, on the earliest diverging branch of the fungal phylogenetic tree.     

Specific and nonspecific immunisation against parasitic infections

Parasitic diseases present major problems to man and his domesticated animals but do not respond easily to conventional vaccination procedures. Vaccines including attenuated stains, killed parasites, homogenates and soluble extracts all produce varying degrees of protection but controlled infections and immunisation with heterologous species or nonspecific antigens also induce protective immunity.     

Stability of tritiated thymidine during prolonged labelling of human blood leukocyte cultures

Zusammenfassung Der Stoffwechsel des³H-Thymidins in Blut-Leukozyten wurde während langfristiger Inkubation studiert. Die Bedingungen waren dieselben, die gewöhnlich for Chromosomenpräparate angewendet werden. So gelang es, menschliche Leukocyten während 72 Stunden mit H³-markiertem Thymidin zu inkubieren, ohne dass das markierte Thymidin durch die Leukozyt-Thymidin-Phosphorylase zerstört wurde.

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This work was supported by research grant No. AM 14529 from the U.S. Public Health Service. D.M. is a Trainee in Genetics (HE 05307) and R.P.C. is a Career Scientist of the Health Research Council of the City of New York.     

Effects of prednisolone and butyrate on agglutinability of HeLa cells by concanavalin A

Cellular and Molecular Life Sciences - Agglutinability by concanavalin A was measured with HeLa65 cells grown with prednisolone or sodium butyrate, 2 compounds that increase the activity of the...     

Complex haplotypes, copy number polymorphisms and coding variation in two recently divergent mouse strains

Inbred mouse strains provide the foundation for mouse genetics. By selecting for phenotypic features of interest, inbreeding drives genomic evolution and eliminates individual variation, while fixing certain sets of alleles that are responsible for the trait characteristics of the strain. Mouse strains 129Sv (129S5) and C57BL/6J, two of the most widely used inbred lines, diverged from common ancestors within the last century, yet very little is known about the genomic differences between them. By comparative genomic hybridization and sequence analysis of 129S5 short insert libraries, we identified substantial structural variation, a complex fine-scale haplotype pattern with a continuous distribution of diversity blocks, and extensive nucleotide variation, including nonsynonymous coding SNPs and stop codons. Collectively, these genomic changes denote the level and direction of allele fixation that has occurred during inbreeding and provide a basis for defining what makes these mouse strains unique.     

A screen of the complete protein kinase gene family identifies diverse patterns of somatic mutations in human breast cancer

We examined the coding sequence of 518 protein kinases, approximately 1.3 Mb of DNA per sample, in 25 breast cancers. In many tumors, we detected no somatic mutations. But a few had numerous somatic mutations with distinctive patterns indicative of either a mutator phenotype or a past exposure.