A comparative analysis of the mechanisms underlying speciation on Lord Howe Island

On Lord Howe Island, speciation is thought to have taken place in situ in a diverse array of distantly related plant taxa (Metrosideros, Howea and Coprosma; Proc. Natl Acad. Sci. USA 108, 2011, 13188). We now investigate whether the speciation processes were driven by divergent natural selection in each genus by examining the extent of ecological and genetic divergence. We present new and extensive, ecological and genetic data for all three genera. Consistent with ecologically driven speciation, outlier loci were detected using genome scan methods. This mechanism is supported by individual-based analyses of genotype-environment correlations within species, demonstrating that local adaptation is currently widespread on the island. Genetic analyses show that prezygotic isolating barriers within species are currently insufficiently strong to allow further population differentiation. Interspecific hybridization was found in both Howea and Coprosma, and species distribution modelling indicates that competitive exclusion may result in selection against admixed individuals. Colonization of new niches, partly fuelled by the rapid generation of new adaptive genotypes via hybridization, appears to have resulted in the adaptive radiation in Coprosma - supporting the 'Syngameon hypothesis'.

Characterisation of copia-like retrotransposons in oil palm ( Elaeis guineensis Jacq.)

The work aimed to isolate and characterise copia-like sequences from Elaeis guineensis. Thirty-two different RT (reverse transcriptase) sequences were isolated from a single oil palm genome using degenerate primers. Extreme sequence heterogeneity was observed. The DNA and protein sequences were assigned to three different classes (A, B, C) on the basis of bootstrapping. We estimated the copy number of the three different classes by using a dot-blot analysis. The comparative results suggest that class-B RT sequences occur at a higher copy number in Cocos nucifera than in Elaeis guineensis and E. oleifera. Class-C RT sequences, which comprise the bulk of isolated sequences, occur in much higher copy number in Elaeis guineensis than in Cocos nucifera, and E. oleifera. Class-A sequences, which have low copy number in Elaeis guineensis and Cocos nucifera, are not present in E. oleifera. Our preliminary results suggest that class-C sequences represent about 5% of the E. guineensis genome, class B, 1% and class A, 0.1%. The methylation status of genomic domains specified by the RT probes was analysed using two pairs of restriction enzymes, each pair having the same recognition sites but different methylation sensitivities ( MspI, HpaII and Sau3AI, MboI). Results from these experiments showed clearly that the genomic domains specified by the RT probes are methylated. These also suggest that a higher copy number appears to correlate to a higher degree of methylation. Our preliminary results suggest that copia-like retrotransposons, because of their ubiquity and diversity, have great potential as genetic markers for plant genome and biodiversity analysis in E. guineensis.

Carpet beetle dermatitis

A 22-year-old man presented with a 5-year history of recurrent urticarial and papulovesicular lesions. Careful history suggested a close examination of his environment. The woolen rug in his bedroom was infested with larvae of a carpet beetle. The insect was identified as Anthrenus verbasci. Fumigation of the house with sulfuryl fluoride (Vikane) resulted in complete clinical recovery. Intradermal injection of the antigenic extract from the larvae showed a wheal and erythema on the patient's skin, and not on normal controls. This suggests that the patient had immediate-type hypersensitivity to some of the antigens extracted from larvae. Electron microscopic pictures of the insect are presented.

Changes in tegumental surface during development of Schistosoma mansoni

The tegumental surface of immature Schistosoma mansoni was studied with the scanning electron microscope. The surfaces of immature males and females bear no resemblance to that of adult worms and are characterized by having many tegumental folds. The tegumental surfaces of immature males and females are similar, and the dorsal and ventral surfaces of the male are similar before formation of the gynecophoral canal. Transition of the tegumental surface from the juvenile to the adult form begins after worms are in copula and have grown to several millimeters in length.

A cell line (SCABER) derived from squamous cell carcinoma of the human urinary bladder

An established cell line derived from a documented squamous cell carcinoma of human urinary bladder is described. The cultured cells retained the characteristic morphology of the tumor of origin for 40 in vitro passages. Numerous desmosomes were found between cultured cells. Chromosome analysis showed hypotetraploidy with no obvious modal number, while distinctive marker chromosomes and a male karyotype were present.

Long-term establishment of a human plasmacyte cell line derived from a patient with IgD multiple myeloma. I. Requirement of a plasmacyte-stimulating factor for the proliferation of myeloma cells in tissue culture

Cell line LA-49, derived from pleural fluid cells of a patient with IgD multiple myeloma, was established in culture and maintained for more than 1 yr. The D-myeloma protein produced in culture was similar to the serum D-myeloma protein in electrophoretic mobility and in delta- and lambda-chain antigens. The plasma cell tumor culture, LA-49, differed from numerous immunoglobulin-producing B-lymphoblastoid cell lines established in this laboratory in: (a) Morphology (revealing various stages of maturation); (b) type of immunoglobulin produced (IgD vs. IgM, IgG, and/or, rarely, IgA); (c) growth characteristics (requirement of plasmacyte-stimulating factor); and (d) chromosomal features (polyploid vs. pseudodiploid). A growth factor was needed for cell division and maintenance of culture viability. This factor was supplied readily by irradiated feeder layers of normal human fibroblasts or conditional media from fibroblast cultures. Preliminary characterization of this factor revealed it to be a protein with a mol wt of approximately 150,000 daltons.