Genetic drift and within-host metapopulation dynamics of HIV-1 infection

Most HIV replication occurs in solid lymphoid tissue, which has prominent architecture at the histological level, which separates groups of productively infected CD4+ cells. Nevertheless, current population models of HIV assume panmixis within lymphoid tissue. We present a simple “metapopulation” model of HIV replication, where the population of infected cells is comprised of a large number of small populations, each of which is established by a few founder viruses and undergoes turnover. To test this model, we analyzed viral genetic variation of infected cell subpopulations within the spleen and demonstrated the action of founder effects as well as significant variation in the extent of genetic differentiation between subpopulations among patients. The combination of founder effects and subpopulation turnover can result in an effective population size much lower than the actual population size and may contribute to the importance of genetic drift in HIV evolution despite a large number of infected cells.

The Role of Cytosolic Potassium and pH in the Growth of Barley Roots1

In an earlier paper we showed that in fully developed barley (Hordeum vulgare L.) root epidermal cells a decrease in cytosolic K+ was associated with an acidification of the cytosol (D.J. Walker, R.A. Leigh, A.J. Miller [1996] Proc Natl Acad Sci USA 93: 10510–10514). To show that these changes in cytosolic ion concentrations contributed to the decreased growth of K+-starved roots, we first measured whether similar changes occurred in cells of the growing zone. Triple-barreled ion-selective microelectrodes were used to measure cytosolic K+ activity and pH in cells 0.5 to 1.0 mm from the root tip. In plants growing from 7 to 21 d after germination under K+-replete conditions, the mean values did not change significantly, with values ranging from 80 to 84 mm for K+ and 7.3 to 7.4 for pH. However, in K+-starved plants (external [K+], 2 μm), the mean cytosolic K+ activity and pH had declined to 44 mm and 7.0, respectively, after 14 d. For whole roots, sap osmolality was always lower in K+-starved than in K+-replete plants, whereas elongation rate and dry matter accumulation were significantly decreased after 14 and 16 d of K+ starvation. The rate of protein synthesis in root tips did not change for K+-replete plants but declined significantly with age in K+-starved plants. Butyrate treatment decreased cytosolic pH and diminished the rate of protein synthesis in K+-replete roots. Procaine treatment of K+-starved roots gave an alkalinization of the cytosol and increased protein synthesis rate. These results show that changes in both cytosolic pH and K+ can be significant factors in inhibiting protein synthesis and root growth during K+ deficiency.

Potassium homeostasis in vacuolate plant cells.

Plant cells contain two major pools of K+, one in the vacuole and one in the cytosol. The behavior of K+ concentrations in these pools is fundamental to understanding the way this nutrient affects plant growth. Triple-barreled microelectrodes have been used to obtain the first fully quantitative measurements of the changes in K+ activity (aK) in the vacuole and cytosol of barley (Hordeum vulgare L.) root cells grown in different K+ concentrations. The electrodes incorporate a pH-selective barrel allowing each measurement to be assigned to either the cytosol or vacuole. The measurements revealed that vacuolar aK declined linearly with decreases in tissue K+ concentration, whereas cytosolic aK initially remained constant in both epidermal and cortical cells but then declined at different rates in each cell type. An unexpected finding was that cytoplasmic pH declined in parallel with cytosolic aK, but acidification of the cytosol with butyrate did not reveal any short-term link between these two parameters. These measurements show the very different responses of the vacuolar and cytosolic K+ pools to changes in K+ availability and also show that cytosolic K+ homeostasis differs quantitatively in different cell types. The data have been used in thermodynamic calculations to predict the need for, and likely mechanisms of, active K+ transport into the vacuole and cytosol. The direction of active K+ transport at the vacuolar membrane changes with tissue K+ status.

A method for distance determination in proteins using a designed metal ion binding site and site-directed spin labeling: evaluation with T4 lysozyme.

The use of molecular genetics to introduce both a metal ion binding site and a nitroxide spin label into the same protein opens the use of paramagnetic metalnitroxyl interactions to estimate intramolecular distances in a wide variety of proteins. In this report, a His-Xaa3-His metal ion binding motif was introduced at the N terminus of the long interdomain helix of T4 lysozyme (Lys-65 --> His/Gln-69 --> His) of three mutants, each containing a single nitroxide-labeled cysteine residue at position 71, 76, or 80. The results show that Cu(II)-induced relaxation effects on the nitroxide can be quantitatively analyzed in terms of interspin distance in the range of 10-25 A using Redfield theory, as first suggested by Leigh [Leigh, J.S. (1970) J. Chem. Phys. 52, 2608-2612]. Of particular interest is the observation that distances can be determined both under rigid lattice conditions in frozen solution and in the presence of motion of the spins at room temperature under physiological conditions. The method should be particularly attractive for investigating structure in membrane proteins that are difficult to crystallize. In the accompanying paper, the technique is applied to a polytopic membrane protein, lactose permease.

Sea lions, sacrifice, and ritual : The symbolism of Moche Island imagery

The Mochica, or Moche (c. 100-800 AD) culture, flourished along the northern Peruvian coast. The Moche did not have a formal written language; as such, contemporary scholars base their analysis on Moche iconography and archaeological burial remains. Especially renown for their ceramic artistry, Moche vessels exhibit a wide range of subject matter, including animal and enigmatic figural representations that evoke terrestrial, marine and possibly, spiritual realms. While research has focused on political organization and the interrelationship between sacrifice and warfare, many marine themes have not been fully explored in the discourse. An exploration of sea lion imagery and sacrifice themes suggests that the marine mammals were ritually hunted. A careful iconographic analysis of island scenes demonstrates ritual and gender affiliations held by the Moche about sea lions. In a multi-disciplinary approach, scientific, archaeological and ethnographic resources substantiate this claim.

Sexualité et corporéité féminines dans le cinéma de réalisatrices contemporaines : une lecture féministe

Ce mémoire de maîtrise étudie le traitement cinématographique de la sexualité et de la corporéité féminines dans le travail de réalisatrices contemporaines. Il prend appui sur les films Anatomie de l’enfer (Catherine Breillat, 2004), Sleeping Beauty (Julia Leigh, 2011), Nuit #1 (Anne Émond, 2011), et Klip (Maja Milos, 2012). Notre hypothèse est que ces réalisatrices adoptent une posture féministe, affirmée ou non, par leur révision des stéréotypes de genre relatifs au corps et à la sexualité féminine. Dans un premier temps, nous nous intéressons à la dynamique érotique entretenue, à travers l’Histoire, entre la femme comme objet de désir et l’homme comme sujet désirant, au cinéma comme ailleurs. Puis, nous analysons la déconstruction des stéréotypes de genre féminins de pudeur et de passivité au sein du corpus choisi. Nous démontrons ainsi qu’en révisant ces stéréotypes, les réalisatrices déjouent volontairement le spectateur dans son expérience érotique. Enfin, nous examinons les stratégies d’auto-réification du corps féminin récurrentes chez les cinéastes étudiées. Nous estimons que les cinéastes s’inscrivent de la sorte dans une tendance à la subversion observable dans les pratiques artistiques féministes contemporaines.

Sexualité et corporéité féminines dans le cinéma de réalisatrices contemporaines : une lecture féministe

Ce mémoire de maîtrise étudie le traitement cinématographique de la sexualité et de la corporéité féminines dans le travail de réalisatrices contemporaines. Il prend appui sur les films Anatomie de l’enfer (Catherine Breillat, 2004), Sleeping Beauty (Julia Leigh, 2011), Nuit #1 (Anne Émond, 2011), et Klip (Maja Milos, 2012). Notre hypothèse est que ces réalisatrices adoptent une posture féministe, affirmée ou non, par leur révision des stéréotypes de genre relatifs au corps et à la sexualité féminine. Dans un premier temps, nous nous intéressons à la dynamique érotique entretenue, à travers l’Histoire, entre la femme comme objet de désir et l’homme comme sujet désirant, au cinéma comme ailleurs. Puis, nous analysons la déconstruction des stéréotypes de genre féminins de pudeur et de passivité au sein du corpus choisi. Nous démontrons ainsi qu’en révisant ces stéréotypes, les réalisatrices déjouent volontairement le spectateur dans son expérience érotique. Enfin, nous examinons les stratégies d’auto-réification du corps féminin récurrentes chez les cinéastes étudiées. Nous estimons que les cinéastes s’inscrivent de la sorte dans une tendance à la subversion observable dans les pratiques artistiques féministes contemporaines.

Dissolved organic carbon concentrations, amino sugar concentrations and highly significantly correlating FT-ICR mass peak magnitudes obtained from solid phase extracted marine dissolved organic matter during POLARSTERN cruise ANT-XXV/1

Dissolved organic matter (DOM) was extracted with solid phase extraction (SPE) from 137 water samples from different climate zones and different depths along an Eastern Atlantic Ocean transect. The extracts were analyzed with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with electrospray ionization (ESI). D14C analyses were performed on subsamples of the SPE-DOM. In addition, the amount of dissolved organic carbon was determined for all water and SPE-DOM samples as well as the yield of amino sugars for selected samples. Linear correlations were observed between the magnitudes of 43% of the FT-ICR mass peaks and the extract D14C values. Decreasing SPE-DOM D14C values went along with a shift in the molecular composition to higher average masses (m/z) and lower hydrogen/carbon (H/C) ratios. The correlation was used to model the SPE-DOM D14C distribution for all 137 samples. Based on single mass peaks a degradation index was developed to compare the degradation state of marine SPE-DOM samples analyzed with FT-ICR MS. A correlation between D14C, degradation index, DOC values and amino sugar yield supports that SPE-DOM analyzed with FT-ICR MS reflects trends of bulk DOM. A relative mass peak magnitude ratio was used to compare aged SPE-DOM and fresh SPE-DOM regarding single mass peaks. The magnitude ratios show a continuum of different reactivities for the single compounds. Only few of the compounds present in the FT-ICR mass spectra are expected to be highly degraded in the oldest water masses of the Pacific Ocean. All other compounds should persist partly thermohaline circulation. Prokaryotic (bacterial) production, transformation and accumulation of this very stable DOM occurs probably primarily in the upper ocean. This DOM is an important contribution to very old DOM, showing that production and degradation are dynamic processes.

A catalogue of rare & curious books, illustrative of the English drama and early English literature ... : which will be sold by auction ... on Monday, 13th June, 1859.

Consignor's name from BM English book sales, p. 286.