Fur seals at Macquarie Island: post-sealing colonisation,trends in abundance and hybridisation of three species

Commercial sealers exterminated the original fur seal population at Macquarie Island in the early 1800s. The first breeding record since the sealing era was not reported until March 1955. Three species of fur seal now occur at Macquarie Island, the Antarctic (Arctocephalus gazella), subantarctic (A. tropicalis) and New Zealand (A. forsteri) fur seal. Census data from 54 breeding seasons in the period 1954–2007 were used to estimate population status and growth for each species. Between the 1950s and 1970s, annual increases in pup production for the species aggregate were low. Between 1986 and 2007, pup production of Antarctic fur seals increased by about 8.8% per year and subantarctic fur seals by 6.8% per year. The New Zealand fur seal, although the most numerous fur seal species on Macquarie Island, has yet to establish a breeding population, due to the absence of reproductively mature females. Hybridisation among species is significant, but appears to be declining. The slow establishment and growth of fur seal populations on Macquarie Island appears to have been affected by its distance from major population centres and hence low immigration rates, asynchronous colonisation times of males and females of each species, and extensive hybridisation.     

Tumor necrosis factor α induces a model of preeclampsia in pregnant baboons (Papio hamadryas)

Preeclampsia is a common disease of pregnancy characterised by maternal hypertension and proteinuria. Abnormal placentation in early pregnancy and abnormal cytokine and anti-angiogenic factor expression are thought to contribute to the clinical syndrome of endothelial dysfunction evident in the second half of gestation. The mechanisms underlying both the placental pathology and its translation to the maternal clinical syndrome are not fully understood. A model of preeclampsia manifest by clinically evident endothelial dysfunction (increased blood pressure and proteinuria) was induced by administration of low-dose TNF-α for 2 weeks at mid-gestation in pregnant baboons (Papio hamadryas). Blood pressure was monitored continuously and remotely by intra-arterial radiotelemetry. Following TNF-α infusion, there was an increase in systolic and diastolic blood pressure and development of proteinuria in pregnant treated animals, but not in pregnant saline controls nor in non-pregnant TNF-α treated animals. The treated pregnant animals also developed elevated plasma soluble FMS-like tyrosine kinase-1 (sFLT-1) and increased placental mRNA expression of sFLT-1 and soluble endoglin (sEng). These results clearly demonstrate that the cytokine TNF-α can induce the clinical and biochemical features of human preeclampsia. The results identify a link between cytokines, placental dysfunction and endothelial dysfunction resulting in a loss of maternal blood pressure control.     

Acetohydroxyacid synthase mutations conferring resistance to imidazolinone or sulfonylurea herbicides in sunflower

Wild biotypes of cultivated sunflower (Helianthus annuus L.) are weeds in corn (Zea mays L.), soybean (Glycine max L.), and other crops in North America, and are commonly controlled by applying acetohydroxyacid synthase (AHAS)-inhibiting herbicides. Biotypes resistant to two classes of AHAS-inhibiting herbicides—imidazolinones (IMIs) or sulfonylureas (SUs)—have been discovered in wild sunflower populations (ANN-PUR and ANN-KAN) treated with imazethapyr or chlorsulfuron, respectively. The goals of the present study were to isolate AHAS genes from sunflower, identify mutations in AHAS genes conferring herbicide resistance in ANN-PUR and ANN-KAN, and develop tools for marker-assisted selection (MAS) of herbicide resistance genes in sunflower. Three AHAS genes (AHAS1, AHAS2, and AHAS3) were identified, cloned, and sequenced from herbicide-resistant (mutant) and -susceptible (wild type) genotypes. We identified 48 single-nucleotide polymorphisms (SNPs) in AHAS1, a single six-base pair insertion-deletion in AHAS2, and a single SNP in AHAS3. No DNA polymorphisms were found in AHAS2 among elite inbred lines. AHAS1 from imazethapyr-resistant inbreds harbored a C-to-T mutation in codon 205 (Arabidopsis thaliana codon nomenclature), conferring resistance to IMI herbicides, whereas AHAS1 from chlorsulfuron-resistant inbreds harbored a C-to-T mutation in codon 197, conferring resistance to SU herbicides. SNP and single-strand conformational polymorphism markers for AHAS1, AHAS2, and AHAS3 were developed and genetically mapped. AHAS1, AHAS2, and AHAS3 mapped to linkage groups 2 (AHAS3), 6 (AHAS2), and 9 (AHAS1). The C/T SNP in codon 205 of AHAS1 cosegregated with a partially dominant gene for resistance to IMI herbicides in two mutant × wild-type populations. The molecular breeding tools described herein create the basis for rapidly identifying new mutations in AHAS and performing MAS for herbicide resistance genes in sunflower.     

Endophytic fungi from Amomum siamense.

Endophytic fungi were isolated from apparently healthy organs of the wild ginger Amomum siamense Criab.. including leaves, pseudostems, and rhizomes, collected from two sites in Doi Suthep-Pui National Park, Thailand. Endophytes were relatively common with an isolate prevalence of 70%-83% at the two sites sampled in the wet and dry seasons. The endophyte assemblages from the two sites were diverse and comprised 7 Ascomycetes and 26 mitosporic fungi. Colletotrichum "gloeosporioides" (Penz.) Penz. & Sacc. in Penz., Glomerella spp., xylariaceous fungi, and Phomopsis spp. were consistently dominant as endophytes on Amomum siamense, but many rare species and mycelia sterilia were also recorded. There was no significant difference between the number of isolates recovered from leaves containing vein tissues and those containing intervein tissues, independent of leaf age. Most taxa showed a preference for either leaf tissue or pseudostems. Two new Ascomycetes species. Gaeumannomyces amomi and Leiosphaerella amomi, were discovered from leaves and rhizomes, respectively, and four species of Pyricularia, including three new species, were isolated from leaves.     

Preclinical model to test human papillomavirus virus (HPV) capsid vaccines in vivo using infectious HPV/cottontail rabbit papillomavirus chimeric papillomavirus particles

A human papillomavirus (HPV) vaccine consisting of virus-like particles (VLPs) was recently approved for human use. It is generally assumed that VLP vaccines protect by inducing type-specific neutralizing antibodies. Preclinical animal models cannot be used to test for protection against HPV infections due to species restriction. We developed a model using chimeric HPV capsid/cottontail rabbit papillomavirus (CRPV) genome particles to permit the direct testing of HPV VLP vaccines in rabbits. Animals vaccinated with CRPV, HPV type 16 (HPV-16), or HPV-11 VLPs were challenged with both homologous (CRPV capsid) and chimeric (HPV-16 capsid) particles. Strong type-specific protection was observed, demonstrating the potential application of this approach.     

Characterization of the human nicotinic acetylcholine receptor subunit alpha (alpha) 9 (CHRNA9) and alpha (alpha) 10 (CHRNA10) in lymphocytes

Though the nicotinic acetylcholine receptor (nAChR) subunits alpha9 and alpha 10 have been thoroughly characterized within hair cells of the organ of Corti in the inner ear, prior studies have shown that they are also expressed in lymphocytes. In this report, we sought to more definitively characterize the nAChR subunits alpha9 and alpha10 within various populations of human lymphocytes. Using a combination of techniques, including RT-PCR, single-cell RT-PCR, Northern and western blot analysis, and immunofluorescence, expression of both alpha9 and alpha 10 was demonstrated in purified populations of T-cells (CD3+, CD4+, CD8+ and the Jurkat, MT2 and CEM T-cell lines) and B-cells (CD19+, CD80+ and EBV-immortalized B-cells). Single-lymphocyte recording techniques failed to identify an ionic current in response to applied acetylcholine in either T-cells or B-cells. These results clearly demonstrate the presence of these nicotinic receptor subunits within several populations of human lymphocytes, implicating their role in the immune response. However, a lack of demonstrated response to applied acetylcholine using standard single-cell recording techniques suggests a physiology different than that seen in hair cells of the inner ear.     

Fractionation of detergent lysates of cells by ammonium sulphate-induced phase separation

A procedure is described for fractionating detergent lysates of cells based on the ability of (NH4)2SO4 to induce phase separation of detergents such as Triton X-100, sodium deoxycholate, and sodium cholate, into detergent-rich and detergent-depleted phases. An analysis of six murine lymphocyte cell surface molecules revealed that the partitioning in Triton X-100 of each molecule was highly dependent upon the (NH4)2SO4 concentration, each antigen partitioning into the detergent-rich phase at a defined salt concentration. In contrast, none of the six molecules appeared in the detergent-rich phase of a Triton X-114 phase separation, even though two of the molecules, namely Ly-2/3 and L3T4, are well-characterized integral membrane proteins. It was also observed that (NH4)2SO4 resulted in the partitioning of many nonmembrane proteins into the detergent-rich phase, indicating that the procedure can be used to fractionate all cellular proteins. By judicious choice of (NH4)2SO4 concentrations, precipitation of cellular proteins at two different (NH4)2SO4 concentrations, and combining the method with subcellular fractionation prior to detergent solubilization, substantial enrichment and concentration of particular cellular proteins could be achieved.     

Potential phytoplankton indicator species for monitoring Baltic coastal waters in the summer period

There are very few time series documenting clear trends of change in the biomass of total phytoplankton or single taxa that coincide with trends of increasing nutrient concentrations. Weekly or biweekly monitoring since 1997 on a cross section of the central Gulf of Finland (NE Baltic Sea) with similar climatic and hydrographic conditions, but different nutrient levels, provided a uniform dataset. In order to evaluate seasonal (June–September) patterns of phytoplankton succession, more than 1,200 samples were statistically analyzed by selecting 12 dominant taxa using wet weight biomass values. In addition, the continuously measured hydrographic parameters on board the ships of opportunity, and simultaneous nutrient analyses gave high frequency information on the water masses. The objective of this study was to identify the taxa that may prove indicative in the assessment of eutrophication in the appropriate monitoring time periods. None of the most common bloom-forming species (Aphanizomenon sp., Nodularia spumigena, and Heterocapsa triquetra) showed reliable correlations with enhanced nutrient concentrations. The species we suggest as reliable eutrophication indicators—oscillatorialean cyanobacteria and the diatoms Cyclotella choctawhatcheeana and Cylindrotheca closterium—showed the best relationships with total phosphorus concentrations. Their maxima appear toward the end of July or in August–September when phytoplankton community structure is more stable, and less frequent observations may give adequate results. Another diatom, Skeletonema costatum, exhibited stronger correlations with dissolved inorganic and total nitrogen in June, during the period of the summer phytoplankton minimum. Guest editors: J. H. Andersen & D. J. Conley Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark