Abundance and distribution of black band disease on coral reefs in the northern Florida keys

The abundance and distribution of black band disease on the reef building coralsMontastraea annularis, M. cavernosa, Colpophyllia natans, Diploria clivosa, D. labyrinthiformis andD. strigosa were determined at Algae Reef, Grecian Rocks and Key Largo Dry Rocks in the Key Largo National Marine Sanctuary, Florida, USA. During July and November of 1992 and July 1993, surveys of permanently marked sites covering 9424m² of reef tract showed that up to 0.72% of 1397 coral colonies of these species were infected with black band disease. The distribution of the disease among the thirty 20-meter diameter sites was clumped, suggesting that the disease is infectious. Year-round monitoring revealed that seasonal disease patterns varied between reefs. Three seasonal patterns were apparent: some coral colonies were infected year round; several colonies exhibited previously unreported reinfection on a seasonal basis; and some exhibited the widely reported pattern of infection limited to the warmer months of the year (sea water temperatures 25 °C or higher).     

Floral structure and pollen morphology of two zinc violets (Viola lutea ssp. calaminaria and V. lutea ssp. westfalica) indicate their taxonomic affinity to Viola lutea

Two zinc violets, the yellow form of the Aachen–Liège area and the blue morph of Blankenrode in western Westphalia, have very restricted occurrence on heavy metal waste heaps. Their taxonomic affinities have not been finally resolved. The flower micromorphological analysis presented here indicates that both zinc violets are closely related to the alpine Viola lutea, in line with our earlier published molecular data, but not with the conclusions of other authors. The zinc violets are classed at the rank of subspecies as V. lutea: ssp. calaminaria for the yellow zinc violet and ssp. westfalica for its blue counterpart. Although the violets examined (V. lutea, V. lutea ssp. calaminaria, V. lutea ssp. westfalica) are closely related, there is no evidence that V. lutea ssp. westfalica is a descendent of V. tricolor. Here we provide the most detailed information on generative organ structure in the four violets studied.     

TDP-43 is a culprit in human neurodegeneration, and not just an innocent bystander

In 2006 the protein TDP-43 was identified as the major ubiquitinated component deposited in the inclusion bodies found in two human neurodegenerative diseases, amyotrophic lateral sclerosis and frontotemporal lobar degeneration. The pathogenesis of both disorders is unclear, although they are related by having some overlap of symptoms and now by the shared histopathology of TDP-43 deposition. Now, in 2008, several papers have been published in quick succession describing mutations in the TDP-43 gene, showing they can be a primary cause of amyotrophic lateral sclerosis. There are many precedents in neurodegenerative disease in which rare single-gene mutations have given great insight into understanding disease processes, which is why the TDP-43 mutations are potentially very important.     

Circadian rhythms of biomarkers of oxidative stress and their characteristics in broiler chickens reared under natural light/dark cycle

For the purpose of studying circadian rhythms of biomarkers of oxidative stress in broiler chickens maintained under natural photoperiod, we collected blood from the wing veins of 10 matured broiler chickens every three hours for a period of 24 h. The blood samples were analyzed for superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA). The fitting in of single cosinor procedure showed that CAT and MDA exhibited clear circadian rhythms, while SOD did not. The amplitude of daily rhythms for the parameters was small, while the acrophases were all restricted to the light phase of the light:dark cycle. In conclusion, to our knowledge, this is the first time investigation of the circadian rhythms of antioxidants in broilers chickens, reared under natural photoperiod in the tropics. The result may be exploited for a more precise targeting of reactive oxygen species, thereby offering better protection for the cells to combat oxidative stress.     

Cleistogamy and phylogenetic position of Viola uliginosa (Violaceae) re‐examined

Viola uliginosa is an endangered species throughout its range in Central Europe. Based on an unusual combination of morphological characters, including a reported lack of cleistogamous (CL) flowers, it was previously placed in the monotypic subsection Repentes, section Viola. Available individual phylogenetic analyses identify V. uliginosa as a lineage deeply embedded in section Viola, but hitherto its exact position was unknown. Here we confirm the occurrence of cleistogamy in V. uliginosa. Unlike other species of section Viola, V. uliginosa produced both chasmogamous and CL flowers at the same time, not at different times of the year (seasonal cleistogamy). The two flower types differed conspicuously in morphology and microstructure, especially in size and shape of the pistil and stamens as confirmed by scanning electron microscopy. Secondly, we resolved the phylogenetic position of V. uliginosa as a lineage deeply embedded in subsection Rostratae by means of a multigene multispecies coalescent analysis using *BEAST. In this analysis, V. mirabilis and V. uliginosa were successive sisters to the rest of subsection Rostratae and, because allopolyploids exist between V. mirabilis and the last one, subsection Rostratae needs to comprise all these taxa to be monophyletic. The evolution of key morphological traits is briefly discussed.     

Chromosome and genome size variation in Luzula (Juncaceae), a genus with holocentric chromosomes

The present study examines chromosome and genome size evolution in Luzula (woodrush; Juncaceae), a monocot genus with holocentric chromosomes. Detailed karyotypes and genome size estimates were obtained for seven Luzula spp., and these were combined with additional data from the literature to enable a comprehensive cytological analysis of the genus. So that the direction of karyotype and genome size changes could be determined, the cytological data were superimposed onto a phylogenetic tree based on the trnL‐F and internal transcribed spacer (ITS) DNA regions. Overall, Luzula shows considerable cytological variation both in terms of chromosome number (2n = 6–66) and genome size (15‐fold variation; 2C = 0.56–8.51 pg; 547.7–8322.8 Mb). In addition, there is considerable diversity in the genomic mechanisms responsible, with the range of karyotypes arising via agmatoploidy (chromosome fission), symploidy (chromosome fusion) and/or polyploidy accompanied, in some cases, by the amplification or elimination of DNA. Viewed in an evolutionary framework, no broad trend in karyotype or genome evolution was apparent across the genus; instead, different mechanisms of karyotype evolution appear to be operating in different clades. It is clear that Luzula exhibits considerable genomic flexibility and tolerance to large, genome‐scale changes. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170 , 529–541.