Interaction of the Ras-related protein associated with diabetes Rad and the putative tumor metastasis suppressor NM23 provides a novel mechanism of GTPase regulation

Rad is the prototypic member of a new class of Ras-related GTPases. Purification of the GTPase-activating protein (GAP) for Rad revealed nm23, a putative tumor metastasis suppressor and a development gene in Drosophila. Antibodies against nm23 depleted Rad-GAP activity from human skeletal muscle cytosol, and bacterially expressed nm23 reconstituted the activity. The GAP activity of nm23 was specific for Rad, was absent with the S105N putative dominant negative mutant of Rad, and was reduced with mutations of nm23. In the presence of ATP, GDP⋅Rad was also reconverted to GTP⋅Rad by the nucleoside diphosphate (NDP) kinase activity of nm23. Simultaneously, Rad regulated nm23 by enhancing its NDP kinase activity and decreasing its autophosphorylation. Melanoma cells transfected with wild-type Rad, but not the S105N-Rad, showed enhanced DNA synthesis in response to serum; this effect was lost with coexpression of nm23. Thus, the interaction of nm23 and Rad provides a potential novel mechanism for bidirectional, bimolecular regulation in which nm23 stimulates both GTP hydrolysis and GTP loading of Rad whereas Rad regulates activity of nm23. This interaction may play important roles in the effects of Rad on glucose metabolism and the effects of nm23 on tumor metastasis and developmental regulation.

Insulin-stimulated translocation of GLUT4 glucose transporters requires SNARE-complex proteins

A major physiological role of insulin is the regulation of glucose uptake into skeletal and cardiac muscle and adipose tissue, mediated by an insulin-stimulated translocation of GLUT4 glucose transporters from an intracellular vesicular pool to the plasma membrane. This process is similar to the regulated docking and fusion of vesicles in neuroendocrine cells, a process that involves SNARE-complex proteins. Recently, several SNARE proteins were found in adipocytes: vesicle-associated membrane protein (VAMP-2), its related homologue cellubrevin, and syntaxin-4. In this report we show that treatment of permeabilized 3T3-L1 adipocytes with botulinum neurotoxin D, which selectively cleaves VAMP-2 and cellubrevin, inhibited the ability of insulin to stimulate translocation of GLUT4 vesicles to the plasma membrane. Furthermore, treatment of the permeabilized adipocytes with glutathione S-transferase fusion proteins encoding soluble forms of VAMP-2 or syntaxin-4 also effectively blocked insulin-regulated GLUT4 translocation. These results provide evidence of a functional role for SNARE-complex proteins in insulin-stimulated glucose uptake and suggest that adipocytes utilize a mechanism of regulating vesicle docking and fusion analogous to that found in neuroendocrine tissues.

Dimethylsulfoniopropionate Biosynthesis in Spartina alterniflora1 : Evidence That S-Methylmethionine and Dimethylsulfoniopropylamine Are Intermediates

The osmoprotectant 3-dimethylsulfoniopropionate (DMSP) occurs in Gramineae and Compositae, but its synthesis has been studied only in the latter. The DMSP synthesis pathway was therefore investigated in the salt marsh grass Spartina alterniflora Loisel. Leaf tissue metabolized supplied [35S]methionine (Met) to S-methyl-l-Met (SMM), 3-dimethylsulfoniopropylamine (DMSP-amine), and DMSP. The 35S-labeling kinetics of SMM and DMSP-amine indicated that they were intermediates and, consistent with this, the dimethylsulfonium moiety of SMM was shown by stable isotope labeling to be incorporated as a unit into DMSP. The identity of DMSP-amine, a novel natural product, was confirmed by both chemical and mass-spectral methods. S. alterniflora readily converted supplied [35S]SMM to DMSP-amine and DMSP, and also readily converted supplied [35S]DMSP-amine to DMSP; grasses that lack DMSP did neither. A small amount of label was detected in 3-dimethylsulfoniopropionaldehyde (DMSP-ald) when [35S]SMM or [35S]DMSP-amine was given. These results are consistent with the operation of the pathway Met → SMM → DMSP-amine → DMSP-ald → DMSP, which differs from that found in Compositae by the presence of a free DMSP-amine intermediate. This dissimilarity suggests that DMSP synthesis evolved independently in Gramineae and Compositae.

Identification and Stereospecificity of the First Three Enzymes of 3-Dimethylsulfoniopropionate Biosynthesis in a Chlorophyte Alga1

Many marine algae produce 3-dimethylsulfoniopropionate (DMSP), a potent osmoprotective compound whose degradation product dimethylsulfide plays a central role in the biogeochemical S cycle. Algae are known to synthesize DMSP via the four-step pathway, l-Met → 4-methylthio-2-oxobutyrate → 4-methylthio-2-hydroxybutyrate → 4-dimethylsulfonio-2-hydroxy-butyrate (DMSHB) → DMSP. Substrate-specific enzymes catalyzing the first three steps in this pathway were detected and partially characterized in cell-free extracts of the chlorophyte alga Enteromorpha intestinalis. The first is a 2-oxoglutarate-dependent aminotransferase, the second an NADPH-linked reductase, and the third an S-adenosylmethionine-dependent methyltransferase. Sensitive radiometric assays were developed for these enzymes, and used to show that their activities are high enough to account for the estimated in vivo flux from Met to DMSP. The activities of these enzymes in other DMSP-rich chlorophyte algae were at least as high as those in E. intestinalis, but were ≥20-fold lower in algae without DMSP. The reductase and methyltransferase were specific for the d-enantiomer of 4-methylthio-2-hydroxybutyrate in vitro, and both the methyltransferase step and the step(s) converting DMSHB to DMSP were shown to prefer d-enantiomers in vivo. The intermediate DMSHB was shown to act as an osmoprotectant, which indicates that the first three steps of the DMSP synthesis pathway may be sufficient to confer osmotolerance.

Insulin-secreting non-islet cells are resistant to autoimmune destruction.

Transgenic nonobese diabetic mice were created in which insulin expression was targeted to proopiomelanocortin-expressing pituitary cells. Proopiomelanocortin-expressing intermediate lobe pituitary cells efficiently secrete fully processed, mature insulin via a regulated secretory pathway, similar to islet beta cells. However, in contrast to the insulin-producing islet beta cells, the insulin-producing intermediate lobe pituitaries are not targeted or destroyed by cells of the immune system. Transplantation of the transgenic intermediate lobe tissues into diabetic nonobese diabetic mice resulted in the restoration of near-normoglycemia and the reversal of diabetic symptoms. The absence of autoimmunity in intermediate lobe pituitary cells engineered to secrete bona fide insulin raises the potential of these cell types for beta-cell replacement therapy for the treatment of insulin-dependent diabetes mellitus.

Roles of nitric oxide in tumor growth.

A subclone of the human colon adenocarcinoma cell line DLD-1, which grew reproducibly as subcutaneous tumors in nude mice, was isolated. Such cells, when engineered to generate nitric oxide (NO) continuously, grew more slowly in vitro than the wild-type parental cells. This growth retardation was reversed by the addition of N-iminoethyl-L-ornithine. In nude mice, however, the tumors from these cells grew faster than those derived from wild-type cells and were markedly more vascularized, suggesting that NO may act as part of a signaling cascade for neovascularization. Recent observations that the generation of NO in human breast and gynecological cancers correlates positively with tumor grade are consistent with this hypothesis. We suggest that NO may have a dual pro- and antitumor action, depending on the local concentration of the molecule.

Chinese Intellectuals and China`s Policy toward Japan

This dissertation aims at integrating two scholarships: state-society relation studies and Chinese foreign policy analysis. I created Two-level Perception Gap Model to analyze different intellectual groups' relations with party-state by confirming Chinese intellectuals play a role in CFP making in general, China's Japan policy in particular. This model is an alternative approach, instead of conventional wisdom patron-client approach, to explain and analyze the pluralized intellectual-state relations in China. This model first analyzed the role of two intellectual groups, namely think tank scholars and popular nationalist, in China's Japan policy making, and then based on these analyses it explains the interactional patterns between these two intellectual groups and party-state. I used three case studies, which represented different types of issue, Chinese attitude toward the U.S.-Japan alliance and the Japanese defense policy, the controversy over the Yasukuni Shrine Visit, and the territorial dispute over the Diaoyu/Senkaku Islands, to examine this model. First, I examined think tank scholar groups and the extent they influenced "core interest issue and sensitive issue (Issue 1)," Chinese attitude toward the U.S.-Japan alliance and the Japanese defense policy, and their international patterns with party-state. Chapter 3 compares the responses of Chinese officials to the changes in the defense policy of Japan to the analyses from the think tank scholars. As the model assumes, results show that think tank scholars' analyses are consistent with China's policy position; nevertheless, it is difficult to confirm their analyses have influence on Chinese attitude toward the U.S.-Japan alliance and the Japanese defense policy. Based on the analysis of journal articles, most articles do not provide policy suggestions or simply provide suggestions that do not deviate from the policy. As Gu's theory of pluralist institutionalism and my hypothesis points out, most think tank scholars are establishment intellectuals so they tend to be self-disciplined. Second, this model provide a new concept "patriotic dilemma" for analyzing the challenge and constraints brought by popular nationalist discourses and public mobilization to Chinese foreign policy decision makers. Chapter 4 investigated the cases study of the controversy over the Yasukuni Shrine Visit, defined as "major/minor interest issue/ sensitive issue (Issue 3)," and the discourses from the popular nationalist, mainly focusing on anti-Japanese activists. The chapter also observes their influence on nationalist public opinions and analyzes how the nationalist public opinions constrain the policy choices among decision makers. Results strongly supported the hypothesis of patriotic dilemma that, although the popular nationalist group and public opinions constrained the policy choices of Chinese decision makers in the short term, they were unable to change the fundamental policy direction. Third, chapter 5 also focuses on anti-Japanese activists and examines the model with the case of the territorial dispute over the Diaoyu/Senkaku Islands. The result supported that hypothesis that China's policy change was not because of the influence from popular nationalist's discourses or public opinions but because of the change of priority of this issue, from major/minor interest issue to core interest issue. These two chapters also indicate that the patron-client model is unable to describe the popular nationalist. An alternative approach, such as the concept "patriotic dilemma" is needed to describe the relations between the popular nationalist and the government.

Annotated almanac, 1761

Almanac with one laid-in leaf. The calendar pages contain minimal annotations and two entries by John Winthrop: "John Rhodes came to talk about Stoughton land" (May 31) and a note about walnuts. The laid-in leaf contains entries by both Winthrops listing deaths in the community, a bill of mortality by John Winthrop, an entry about an earthquake (November 1), and a few entries by Hannah Winthrop about the weather, a northern light, and a short list of the "wine of Dr. Kneeland" (December 29).

College Book 6, 1726-1790

College Book 6 is often referred to as the Hollis book, reflecting its contents. It was created following an April 4, 1726 Corporation vote that "Mr. Treasurer procure a Book, into which shall be transmitted, and a Register kept of, Mr Hollis's Rules, orders, Gifts & Bounties past & to come; together with ye Names & age, & Charecter of his Scholars, ye time of their Entry and Dismission; and also all ye Votes of ye Overseers & Corporation from time to time relating to ye said orders, Bounties & Scholars of the said Mr Hollis." Entries are primarily in Benjamin Wadsworth's hand and record donations from Thomas Hollis and his descendants, with transcriptions of related Corporation minutes. They also provide detailed information about the allocation of Hollis funds and scholarships, and the rules governing the Hollis Professorship of Divinity (established in 1721) and the Hollis Professorship of Mathematics and Natural Philosophy (established in 1727). The volume also contains inventories of books in the official library of the Hollis Professor of Divinity and two inventories – created in 1779 and in 1790 – of the mathematical and philosophical apparatus purchased with Hollis funds. Many entries related to the purchase of scientific instruments and supplies include the cost in sterling of each item. Also included are entries related to financial accounts and expenditures, as well as copies of letters from Nathaniel Hollis.

Human naïve regulatory T-cells feature high steady-state turnover and are maintained by IL-7

Naïve FoxP3-expressing regulatory T-cells (Tregs) are essential to control immune responses via continuous replenishment of the activated-Treg pool with thymus-committed suppressor cells. The mechanisms underlying naïve-Treg maintenance throughout life in face of the age-associated thymic involution remain unclear. We found that in adults thymectomized early in infancy the naïve-Treg pool is remarkably well preserved, in contrast to conventional naïve CD4 T-cells. Naïve-Tregs featured high levels of cycling and pro-survival markers, even in healthy individuals, and contrasted with other circulating naïve/memory CD4 T-cell subsets in terms of their strong γc-cytokine-dependent signaling, particularly in response to IL-7. Accordingly, ex-vivo stimulation of naïve-Tregs with IL-7 induced robust cytokine-dependent signaling, Bcl-2 expression, and phosphatidylinositol 3-kinase (PI3K)-dependent proliferation, whilst preserving naïve phenotype and suppressive capacity. Altogether, our data strongly implicate IL-7 in the thymus-independent long-term survival of functional naïve-Tregs, and highlight the potential of targeting the IL-7 pathway to modulate Tregs in different clinical settings.

Differences in larval nutritional requirements and female oviposition preference reflect the order of fruit colonization of Zaprionus indianus and Drosophila simulans

Species coexist using the same nutritional resource by partitioning it either in space or time, but few studies explore how species-specific nutritional requirements allow partitioning. Zaprionus indianus and Drosophila simulans co-exist in figs by invading the fruit at different stages; Z. indianus colonizes ripe figs, whereas D. simulans oviposits in decaying fruit. Larvae feed on yeast growing on the fruit, which serves as their primary protein source. Because yeast populations increase as fruit decays, we find that ripe fruit has lower protein content than rotting fruit. Therefore, we hypothesized that Z. indianus and D. simulans larvae differ in their dietary requirements for protein. We used nutritional geometry to assess the effects of protein and carbohydrate concentration in the larval diet on life history characters in both species. Survival, development time, and ovariole number respond differently to the composition of the larval diet, with Z. indianus generally performing better across a wider range of protein concentrations. Correspondingly, we found that Z. indianus females preferred to lay eggs on low protein foods, while D. simulans females chose higher protein foods for oviposition when competing with Z. indianus. We propose the different nutritional requirements and oviposition preference of these two species allows them to temporally partition their habitat.

¿Qué significa tener una beca de estudio de la Comisión de Investigaciones Científicas de la Provincia de Buenos Aires? Relato de una experiencia

Las becas que otorga la Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC) cada año se presentan como una opción interesante para alumnos avanzados y graduados que deseen iniciarse en la investigación científica y técnica. Tradicionalmente, el área de desempeño laboral y profesional de los graduados de las carreras de Licenciatura y Profesorado en Educación Física ha sido la docencia, por ello, este documento tiene por objetivo explicar, a partir de una experiencia personal, qué se requiere para acceder a una Beca de Estudio de la Comisión de Investigaciones Científicas de la Provincia de Buenos Aires y cuáles son los antecedentes más importantes para la aprobación de este tipo de beca. Se expondrá el plan de investigación de la autora, el cual fue aprobado y continúa en actividad al momento, y por último, se describirán las tareas que el becario debe desempeñar una vez obtenida la Beca de Estudio

¿Qué significa tener una beca de estudio de la Comisión de Investigaciones Científicas de la Provincia de Buenos Aires? Relato de una experiencia

Las becas que otorga la Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC) cada año se presentan como una opción interesante para alumnos avanzados y graduados que deseen iniciarse en la investigación científica y técnica. Tradicionalmente, el área de desempeño laboral y profesional de los graduados de las carreras de Licenciatura y Profesorado en Educación Física ha sido la docencia, por ello, este documento tiene por objetivo explicar, a partir de una experiencia personal, qué se requiere para acceder a una Beca de Estudio de la Comisión de Investigaciones Científicas de la Provincia de Buenos Aires y cuáles son los antecedentes más importantes para la aprobación de este tipo de beca. Se expondrá el plan de investigación de la autora, el cual fue aprobado y continúa en actividad al momento, y por último, se describirán las tareas que el becario debe desempeñar una vez obtenida la Beca de Estudio

Geochemistry of ODP Hole 111-504B basalts (Table 2)

Fifty samples of basalt recovered during ODP Leg 111 from the dikes (Layer 2C) of Hole 504B (1350.0-1562.3 m below seafloor) were analyzed by X-ray-fluorescence techniques. All of the samples are highly depleted in magmaphile elements relative to other mid-ocean ridge basalts, with TiO2 = 0.75-1.24 wt%, Na2O = 1.59-2.22 wt%, Zr = 38-64 ppm, Nb = 0.3-1.5 ppm, and Y = 20-30 ppm (for samples containing 0%-2% phenocrysts), but have ratios of highly incompatible elements similar to normal Type I mid-ocean ridge basalts (e.g., Zr/Nb > 30). Abundances of compatible elements are similar to those of typical mid-ocean ridge basalts, with MgO = 7.2-9.2 wt%, Fe2O3* = 9.3-12.5 wt%, Ni = 55-164 ppm, and Cr = 26-388 ppm. Approximately 2% of the samples recovered from the top part of Hole 504B are similar to normal Type I or Type II ocean floor basalts. However, all of the analyzed Leg 111 samples from Hole 504B are depleted basalts. Aphyric dike rocks from Leg 111 are virtually identical to the depleted aphyric samples recovered from the pillow lavas and dikes in the upper 1075 m of Hole 504B during DSDP Legs 69, 70, and 83, with the exception of elements readily altered by seawater (Sr, Rb, and K). These elements reach a maximum in both abundance and variability in the pillow lavas of the upper 571.5 m of Hole 504B and decline to more constant values in the dike system sampled on Legs 83 and 111, apparently as a result of a decrease in porosity and increase in alteration temperatures relative to the pillow lavas. Based on compositional similarities to the vast majority of the pillows and flows, the dikes sampled on Leg 111 appear to be the feeder system for the pillow lavas in the upper part of Hole 504B. The incompatible-element-depleted compositions of the Costa Rica Rift Zone basalts are consistent with multistage melting of a normal mid-ocean ridge source.