Release and Consumption of DMSP from Emiliania Huxleyi during grazing by Oxyrrhis Marina

Degradation and release to solution of intracellular dimethylsulfoniopropionate (DMSP) from Emiliania huxleyi 370 was observed during grazing by the heterotrophic dinoflagellate Oxyrrhis marina in 24 h bottle incubations. Between 30 and 70% of the lost algal DMSP was metabolized by the grazers without production of dimethylsulfide (DMS) when grazer densities were 150 to 450/ml. The rest was released to solution and about 30% was converted to DMS by bacteria associated with the grazer culture. These experiments demonstrate that grazing by herbivorous protists may be an important sink for DMSP in marine waters, removing a potential source of DMS. Microzooplankton grazing may also indirectly increase the production of DMS by transferring algal DMSP to the dissolved pool, making it available for bacterial metabolism

Climate variability, oceanography, bowhead whale distribution, and Iñupiat subsistence whaling near Barrow, Alaska

Author Posting. © Arctic Institute of North America, 2010. This article is posted here by permission of Arctic Institute of North America for personal use, not for redistribution. The definitive version was published in Arctic 63 (2010): 179-194.The annual migration of bowhead whales (Balaena mysticetus) past Barrow, Alaska, has provided subsistence hunting to Iñupiat for centuries. Bowheads recurrently feed on aggregations of zooplankton prey near Barrow in autumn. The mechanisms that form these aggregations, and the associations between whales and oceanography, were investigated using field sampling, retrospective analysis, and traditional knowledge interviews. Oceanographic and aerial surveys were conducted near Barrow during August and September in 2005 and 2006. Multiple water masses were observed, and close coupling between water mass type and biological characteristics was noted. Short-term variability in hydrography was associated with changes in wind speed and direction that profoundly affected plankton taxonomic composition. Aggregations of ca. 50–100 bowhead whales were observed in early September of both years at locations consistent with traditional knowledge. Retrospective analyses of records for 1984–2004 also showed that annual aggregations of whales near Barrow were associated with wind speed and direction. Euphausiids and copepods appear to be upwelled onto the Beaufort Sea shelf during Eor SEwinds. A favorable feeding environment is produced when these plankton are retained and concentrated on the shelf by the prevailing westward Beaufort Sea shelf currents that converge with the Alaska Coastal Current flowing to the northeast along the eastern edge of Barrow Canyon.This work was supported by NSF Grants OPPPP-0436131 to C. Ashjian (S. Braund Subcontract), OPPPP-0436110 to R. Campbell, OPPPP-0436127 to W. Maslowski, OPPPP-0436009 to C. Nicolson and J. Kruse, OPPPP-043166 to S. Okkonen, and OPPPP-0435956 to Y. Spitz, E. Sherr, and B. Sherr

Association between health-related quality of life and menopausal status and symptoms in women living with HIV aged 45-60 years in England: An analysis of the PRIME study

OBJECTIVES: The aim of this study was to compare the health-related quality of life between mid-life women with HIV and the general population and to investigate the association between health-related quality of life and menopausal (1) status and (2) symptoms among women with HIV. METHODS: Cross-sectional data of women with HIV aged 45-60 years from the Positive Transitions Through the Menopause Study. Health-related quality of life was assessed using the Euroqol questionnaire with utility scores categorizing health as perfect (score = 1.00), sub-optimal (0.75-0.99) or poor (< 0.75). Scores were compared between Positive Transitions Through the Menopause study participants and women (aged 45-59 years) from the Health Survey for England. Associations between health-related quality of life and menopausal status/symptoms in Positive Transitions Through the Menopause participants were assessed using a multivariable two-part regression model, the results of which are combined to produce a single marginal effect. RESULTS: In total, 813 women from the Positive Transitions Through the Menopause study were included (median age 49 (interquartile range: 47-53) years); the majority were of Black African ethnicity (72.2%). Overall, 20.9%, 43.7% and 35.3% of women were pre-, peri- and post-menopausal, respectively, and 69.7% experienced mild/moderate/severe menopausal symptoms. Approximately, 40% reported perfect health, 22.1% sub-optimal health and 39.0% poor health, similar to women from the Health Survey for England (perfect health: 36.9%, sub-optimal health: 25.2%, poor health: 37.9%). In multivariable models, we found an association between health-related quality of life and peri-menopausal status (marginal effect: 0.07 (0.02, 0.12)); however, the association with post-menopausal status was attenuated (marginal effect: 0.01 (-0.05, 0.06)). There remained a strong association between lower utility scores and moderate (marginal effect: 0.16 (0.11, 0.20)) and severe (marginal effect: 0.32 (0.27, 0.39)) menopausal symptoms. CONCLUSION: There were no differences in health-related quality of life between women with HIV (Positive Transitions Through the Menopause participants) and women from the Health Survey for England dataset. Among Positive Transitions Through the Menopause participants, health-related quality of life was reduced in peri-menopausal women and those with increasingly severe menopausal symptoms. Our findings highlight the importance of proactive assessment of menopausal status and symptoms to optimize health-related quality of life in women living with HIV as they reach mid-life and beyond

Sensitivities of the Proton-Nucleus Elastical Scattering Observables of 6He and 8He at Intermediate Energies

We investigate the use of proton-nucleus elastic scattering experiments using secondary beams of 6He and 8He to determine the physical structure of these nuclei. The sensitivity of these experiments to nuclear structure is examined by using four different nuclear structure models with different spatial features using a full-folding optical potential model. The results show that elastic scattering at intermediate energies (<100 MeV per nucleon) is not a good constraint to be used to determine features of structure. Therefore researchers should look elsewhere to put constraints on the ground state wave function of the 6He and 8He nuclei.Comment: To be published in Phys. Rev.

Synthetic Lethality of Chk1 Inhibition Combined with p53 and/or p21 Loss During a DNA Damage Response in Normal and Tumor Cells

Cell cycle checkpoints ensure genome integrity and are frequently compromised in human cancers. A therapeutic strategy being explored takes advantage of checkpoint defects in p53-deficient tumors in order to sensitize them to DNA-damaging agents by eliminating Chk1-mediated checkpoint responses. Using mouse models, we demonstrated that p21 is a key determinant of how cells respond to the combination of DNA damage and Chk1 inhibition (combination therapy) in normal cells as well as in tumors. Loss of p21 sensitized normal cells to the combination therapy much more than did p53 loss and the enhanced lethality was partially blocked by CDK inhibition. In addition, basal pools of p21 (p53 independent) provided p53 null cells with protection from the combination therapy. Our results uncover a novel p53-independent function for p21 in protecting cells from the lethal effects of DNA damage followed by Chk1 inhibition. As p21 levels are low in a significant fraction of colorectal tumors, they are predicted to be particularly sensitive to the combination therapy. Results reported in this study support this prediction

Structure of the mirror nuclei 9^9Be and 9^9B in a microscopic cluster model

The structure of the mirror nuclei $^9$Be and $^9$B is studied in a microscopic $\alpha+ \alpha+ n$ and $\alpha+ \alpha+ p$ three-cluster model using a fully antisymmetrized 9-nucleon wave function. The two-nucleon interaction includes central and spin-orbit components and the Coulomb potential. The ground state of $^9$Be is obtained accurately with the stochastic variational method, while several particle-unbound states of both $^9$Be and $^9$B are investigated with the complex scaling method.The calculation for $^9$Be supports the recent identification for the existence of two broad states around 6.5 MeV, and predicts the $\frac{3}{2}^{-}_2$ and $\frac{5}{2}^{-}_2$ states at about 4.5 MeV and 8 MeV, respectively. The similarity of the calculated spectra of $^9$Be and $^9$B enables one to identify unknown spins and parities of the $^9$B states. Available data on electromagnetic moments and elastic electron scatterings are reproduced very well. The enhancement of the $E$1 transition of the first excited state in $^9$Be is well accounted for. The calculated density of $^9$Be is found to reproduce the reaction cross section on a Carbon target. The analysis of the beta decay of $^9$Li to $^9$Be clearly shows that the wave function of $^9$Be must contain a small component that cannot be described by the simple $\alpha+ \alpha+ n$ model. This small component can be well accounted for by extending a configuration space to include the distortion of the $\alpha$-particle to $t+p$ and $h+n$ partitions.Comment: 24 page

A bovine lymphosarcoma cell line infected with theileria annulata exhibits an irreversible reconfiguration of host cell gene expression

Theileria annulata, an intracellular parasite of bovine lymphoid cells, induces substantial phenotypic alterations to its host cell including continuous proliferation, cytoskeletal changes and resistance to apoptosis. While parasite induced modulation of host cell signal transduction pathways and NFκB activation are established, there remains considerable speculation on the complexities of the parasite directed control mechanisms that govern these radical changes to the host cell. Our objectives in this study were to provide a comprehensive analysis of the global changes to host cell gene expression with emphasis on those that result from direct intervention by the parasite. By using comparative microarray analysis of an uninfected bovine cell line and its Theileria infected counterpart, in conjunction with use of the specific parasitacidal agent, buparvaquone, we have identified a large number of host cell gene expression changes that result from parasite infection. Our results indicate that the viable parasite can irreversibly modify the transformed phenotype of a bovine cell line. Fifty percent of genes with altered expression failed to show a reversible response to parasite death, a possible contributing factor to initiation of host cell apoptosis. The genes that did show an early predicted response to loss of parasite viability highlighted a sub-group of genes that are likely to be under direct control by parasite infection. Network and pathway analysis demonstrated that this sub-group is significantly enriched for genes involved in regulation of chromatin modification and gene expression. The results provide evidence that the Theileria parasite has the regulatory capacity to generate widespread change to host cell gene expression in a complex and largely irreversible manner

Power to participants: methodological and ethical reflections from a decade of adolescent advisory groups in South Africa

Whilst the HIV response has made significant progress in increasing representation of adults affected by HIV, the meaningful inclusion of children and adolescents has lagged. But this may be a pivotal moment of change. We report on a decade of conducting adolescent advisory groups in South Africa, to reflect on youth advisory processes. Data was collected from 2008 to 2018 from adolescent advisors (n = 60) and researchers (n = 25), and included feedback sessions, social media, anonymous “post-boxes” and interviews. Findings include the value of adolescent involvement in multiple stages of research co-creation and engagement in policy processes, the need for a safe environment and supporting adolescents living in extreme vulnerability. We also discuss the reconfiguring of power and personal relationships, and logistical and financial needs of adolescent advisory groups. Findings suggest that adolescent co-creation of research is feasible, even with very vulnerable adolescents, although ethical considerations need to be carefully addressed. Benefits include increased methodological rigour, enhanced adolescent acceptability of research and the recalibration of research dynamics for the empowerment of their target beneficiaries. Future studies could benefit from meaningfully involving adolescents through youth advisory groups