Dimorphism in the Antarctic cryptophyte Geminigera cryophila (Cryptophyceae).

A pink to red-pigmented cryptophyte of undetermined taxonomic affinity was isolated and cloned from two seasonally ice-covered. meromictic, saline Antarctic aquatic environments: Bayly Bay (BB) and Ace Lake (AL). The clones shared a number of morphological and ultrastructural similarities with other cryptomonad genera, which confounded identification by light and electron microscopy. Cellular pigments extracted from the AL clone showed an absorption maximum corresponding to the biliprotein Cr-phycoerythrin 545, thus narrowing its potential taxonomic affinities. Partial 18S SSU ribosomal gene sequences were isolated from both the AL and the BB cryptomonads' nuclear rDNA, whereas PCR-amplified and their molecular phylogenies inferred from the subject sequences. Our results, and the results of another study that used our prepublished sequence data, invariably resolved both clones as very close matches with the Antarctic cryptophyte, Geminigera cryophila. When combined, the morphological, chemical, and molecular evidence suggested that both of our cryptophyte clones were a cryptomorph of the G. cryophila campylomorph. Slight differences between the AL and BB nuclear tree reconstructions suggested divergent microevolution following long-term isolation of the AL population from the surrounding marine ecosystem. This study provides further compelling evidence that certain Cryptophyceae engage in a life-history strategy, which includes alternating morphologically distinct cell-types (dimorphism); cell-types which without molecular analyses could be mistaken as novel taxa.

New Genetic Loci Associated With Chronic Kidney Disease in an Indigenous Australian Population.

The common occurrence of renal disease in Australian Aboriginal populations such as Tiwi Islanders may be determined by environmental and genetic factors. To explore genetic contributions, we performed a genome-wide association study (GWAS) of urinary albumin creatinine ratio (ACR) in a sample of 249 Tiwi individuals with genotype data from a 370K Affymetrix single nucleotide polymorphism (SNP) array. A principal component analysis (PCA) of the 249 individual Tiwi cohort and samples from 11 populations included in phase III of the HapMap Project indicated that Tiwi Islanders are a relatively distinct and unique population with no close genetic relationships to the other ethnic groups. After adjusting for age and sex, the proportion of ACR variance explained by the 370K SNPs was estimated to be 37% (using the software GCTA.31; likelihood ratio = 8.06, p-value = 0.002). The GWAS identified eight SNPs that were nominally significantly associated with ACR (p < 0.0005). A replication study of these SNPs was performed in an independent cohort of 497 individuals on the eight SNPs. Four of these SNPs were significantly associated with ACR in the replication sample (p < 0.05), rs4016189 located near the CRIM1 gene (p = 0.000751), rs443816 located in the gene encoding UGT2B11 (p = 0.022), rs6461901 located near the NFE2L3 gene, and rs1535656 located in the RAB14 gene. The SNP rs4016189 was still significant after adjusting for multiple testing. A structural equation model (SEM) demonstrated that the rs4016189 SNP was not associated with other phenotypes such as estimated glomerular filtration rate (eGFR), diabetes, and blood pressure.

Australian dust storm associated with extensive Aspergillus sydowii fungal "bloom" in coastal waters.

A massive central Australian dust storm in September 2009 was associated with abundant fungal spores (150,000/m(3)) and hyphae in coastal waters between Brisbane (27°S) and Sydney (34°S). These spores were successfully germinated from formalin-preserved samples, and using molecular sequencing of three different genes (the large subunit rRNA gene [LSU], internal transcribed spacer [ITS[, and beta-tubulin gene), they were conclusively identified as Aspergillus sydowii, an organism circumstantially associated with gorgonian coral fan disease in the Caribbean. Surprisingly, no human health or marine ecosystem impacts were associated with this Australian dust storm event. Australian fungal cultures were nontoxic to fish gills and caused a minor reduction in the motility of Alexandrium or Chattonella algal cultures but had their greatest impacts on Symbiodinium dinoflagellate coral symbiont motility, with hyphae being more detrimental than spores. While we have not yet seen any soft coral disease outbreaks on the Australian Great Barrier Reef similar to those observed in the Caribbean and while this particular fungal population was non- or weakly pathogenic, our observations raise the possibility of future marine ecosystem pathogen impacts from similar dust storms harboring more pathogenic strains.

PHOTOSYNTHETIC PIGMENT AND GENETIC DIFFERENCES BETWEEN TWO SOUTHERN OCEAN MORPHOTYPES OF EMILIANIA HUXLEYI (HAPTOPHYTA)1.

The widespread coccolithophorid Emiliania huxleyi (Lohmann) W. W. Hay et H. Mohler plays a pivotal role in the carbon pump and is known to exhibit significant morphological, genetic, and physiological diversity. In this study, we compared photosynthetic pigments and morphology of triplicate strains of Southern Ocean types A and B/C. The two morphotypes differed in width of coccolith distal shield elements (0.11-0.24 µm, type A; 0.06-0.12 µm, type B/C) and morphology of distal shield central area (grill of curved rods in type A; thin plain plate in type B/C) and showed differences in carotenoid composition. The mean 19'-hexanoyloxyfucoxanthin (Hex):chl a ratio in type B/C was >1, whereas the type A ratio was <1. The Hex:fucoxanthin (fuc) ratio for type B/C was 11 times greater than that for type A, and the proportion of fuc in type A was 6 times higher than that in type B/C. The fuc derivative 4-keto-19'-hexanoyloxyfucoxanthin (4-keto-hex) was present in type A but undetected in B/C. DNA sequencing of tufA distinguished morphotypes A, B/C (indistinguishable from B), and R, while little variation was observed within morphotypes. Thirty single nucleotide polymorphisms were identified in the 710 bp tufA sequence, of which 10 alleles were unique to B/C and B morphotypes, seven alleles were unique to type A, and six alleles were unique to type R. We propose that the morphologically, physiologically, and genetically distinct Southern Ocean type B/C sensu Young et al. (2003) be classified as E. huxleyi var. aurorae var. nov. S. S. Cook et Hallegr.

DNA sequence and expression variation of hop (Humulus lupulus) valerophenone synthase (VPS), a key gene in bitter acid biosynthesis.

BACKGROUND: The hop plant (Humulus lupulus) is a source of many secondary metabolites, with bitter acids essential in the beer brewing industry and others having potential applications for human health. This study investigated variation in DNA sequence and gene expression of valerophenone synthase (VPS), a key gene in the bitter acid biosynthesis pathway of hop. METHODS: Sequence variation was studied in 12 varieties, and expression was analysed in four of the 12 varieties in a series across the development of the hop cone. RESULTS: Nine single nucleotide polymorphisms (SNPs) were detected in VPS, seven of which were synonymous. The two non-synonymous polymorphisms did not appear to be related to typical bitter acid profiles of the varieties studied. However, real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis of VPS expression during hop cone development showed a clear link with the bitter acid content. The highest levels of VPS expression were observed in two triploid varieties, 'Symphony' and 'Ember', which typically have high bitter acid levels. CONCLUSIONS: In all hop varieties studied, VPS expression was lowest in the leaves and an increase in expression was consistently observed during the early stages of cone development.

CTLA-4 and multiple sclerosis: the A49G single nucleotide polymorphism shows no association with multiple sclerosis in a Southern Australian population.

Multiple sclerosis (MS) is a chronic autoimmune disorder that causes inflammatory demyelination and axonal damage in the central nervous system (CNS). We have investigated whether the A49G single nucleotide polymorphism (SNP) genotype of the CTLA-4 gene influenced the development of MS in Southern Australians as well as the interaction of this SNP with the DRB1*15 haplotype. There were no significant (P<0.05) associations between the A49G genotype and risk of MS, either before or after stratification for presence of the DR15 haplotype.