University of Hawaii at Manoa

About: University of Hawaii at Manoa is a education organization based out in Honolulu, Hawaii, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 13693 authors who have published 25161 publications receiving 1023924 citations.

rst and its paralogue kirre act redundantly during embryonic muscle development in Drosophila

Abstract: The polynucleate myotubes of vertebrates and invertebrates form by fusion of myoblasts. We report the involvement of the Drosophila melanogaster Roughest (Rst) protein as a new membrane-spanning component in this process. Rst is strongly expressed in mesodermal tissues during embryogenesis, but rst null mutants display only subtle embryonic phenotypes. Evidence is presented that this is due to functional redundancy between Rst and its paralogue Kirre. Both are highly related single-pass transmembrane proteins with five extracellular immunoglobulin domains and three conserved motifs in the intracellular domain. The expression patterns of kirre and rst overlap during embryonic development in muscle founder cells. Simultaneous deletion of both genes causes an almost complete failure of fusion between muscle founder cells and fusion-competent myoblasts. This defect can be rescued by one copy of either gene. Moreover, Rst, like Kirre is a myoblast attractant.

Eddy-mean flow interaction in the decadally modulating Kuroshio Extension system

Abstract: Satellite altimeter sea-surface height (SSH) data of the past 16 years are used to investigate the decadal changes of the Kuroshio Extension (KE) system that oscillated between a stable and an unstable dynamic state. During the stable state of 10/1992–06/1995 and 01/2002–12/2004, the KE jet was intense and had a northerly zonal mean path and a well-defined southern recirculation gyre. During the unstable state of 07/1995–12/2001 and 01/2005–present, the KE jet had a reduced eastward transport and a more southerly flow path. Transitions between the two dynamic states are caused by the basin-scale wind-stress curl forcing in the eastern North Pacific related to the Pacific decadal oscillations (PDOs) or the North Pacific Gyre Oscillations (NPGOs). During the positive PDO (or negative NPGO) phase, the intensified Aleutian Low generates negative SSH anomalies in the eastern North Pacific through Ekman divergence. As these wind-induced negative SSH anomalies propagate to the west as baroclinic Rossby waves, they weaken the zonal KE jet and shift its path southward. As its path is pushed southward ( ∼ 32 ∘ N ) , the deep-reaching KE jet has to ride over the shallow Shatsky Rise, generating localized disturbances that lead to their subsequent development along the KE jet west of the Shatsky Rise. The sequence opposite to that listed above occurs when the PDO (NPGO) changes to its negative (positive) phase. After the KE system transitions from a stable to unstable state, the enhanced eddy interaction is found to strengthen both the southern recirculation gyre and quasi-stationary meanders along the KE's upstream path. This nonlinear eddy interaction is important in determining the amplitude of the observed decadal KE variability.

Mitochondrial DNA decrease in subcutaneous adipose tissue of HIV-infected individuals with peripheral lipoatrophy.

Abstract: Objective To determine whether the peripheral fat wasting (lipodystrophy), which is seen in association with highly active antiretroviral therapy (HAART) that includes a nucleoside reverse transcriptase inhibitor (NRTI), is associated with a decrease in subcutaneous adipose tissue mitochondrial DNA (mtDNA) content or with large mtDNA deletions or insertions. Design A four cohort cross-sectional study. Methods The mtDNA content of subcutaneous fat tissue from the neck, abdomen and thigh was determined by polymerase chain reaction utilizing the amplification of three different mtDNA fragments. The results from HIV-infected patients with peripheral fat wasting following more than 6 months of NRTI-containing HAART were compared with the results from three different control cohorts: HIV-infected patients with a similar treatment history without lipodystrophy; HIV-infected patients naive to antiretroviral therapy and HIV sero-negative participants. Results A decrease in mtDNA content was found in HAART-treated HIV-infected patients with peripheral fat wasting in comparison with subjects in the control cohorts. No large mitochondrial deletions or insertions were found. Conclusions Lipodystrophy with peripheral fat wasting following treatment with NRTI-containing HAART is associated with a decrease in subcutaneous adipose tissue mtDNA content.

Maturation and sperm penetration of canine ovarian oocytes in vitro.

Abstract: Canine ovarian oocytes were cultured in a medium consisting of TC medium 199, fetal calf serum and antibiotics. Ninety-nine percent of the apparently healthy oocytes were in the germinal vesicle (dictyate) stage when recovered from the ovaries; 25% of them reached metaphase I or II by 72 hours of culture. Washed ejaculated spermatozoa were added to BWW medium containing oocytes which had either been removed directly from the follicles or which had been cultured for 24--72 hours. The earliest acrosome reaction and zona penetration by spermatozoa were seen at seven hours after insemination. Seventy-four percent of the oocytes examined between 11 and 24 hours after insemination showed evidence of zona penetration by spermatozoa. Neither the condition of the oocyte vitellus nor the stage of nuclear maturation influenced the incidence of zona penetration. Decondensing sperm nuclei were found in the vitellus of 27% of the oocytes which had not been cultured and in the vitellus of 20% of those which had been cultured for 24--72 hours and were in various stages of maturation. These results indicate that (1) canine ovarian oocytes can be matured in vitro, (2) the spermatozoa require capacitation which takes approximately seven hours in vitro and (3) maturation of the oocytes is not required for sperm passage through the zona pellucida or entry into the vitellus nor for sperm nuclear decondensation.

Ice sheets as a significant source of highly reactive nanoparticulate iron to the oceans

Abstract: The Greenland and Antarctic Ice Sheets cover ~ 10% of global land surface, but are rarely considered as active components of the global iron cycle. The ocean waters around both ice sheets harbour highly productive coastal ecosystems, many of which are iron limited. Measurements of iron concentrations in subglacial runoff from a large Greenland Ice Sheet catchment reveal the potential for globally significant export of labile iron fractions to the near-coastal euphotic zone. We estimate that the flux of bioavailable iron associated with glacial runoff is 0.40-2.54 Tg per year in Greenland and 0.06-0.17 Tg per year in Antarctica. Iron fluxes are dominated by a highly reactive and potentially bioavailable nanoparticulate suspended sediment fraction, similar to that identified in Antarctic icebergs. Estimates of labile iron fluxes in meltwater are comparable with aeolian dust fluxes to the oceans surrounding Greenland and Antarctica, and are similarly expected to increase in a warming climate with enhanced melting.