Recent progress in lanthanide-catalyzed organic reactions in protic media

Lanthanide triflates are stable in water. It is possible for lanthanides to undergo many organic reactions in environmentally friendly solvents. This makes lanthanides very promising in the field of green chemistry. This review describes the recent development of the lanthanidecatalyzed organic reactions in protic solvents. Those reactions include Diels-Alder, Aldol, Allylation, acetalization, pericyclization, radical reactions as well as some newlydeveloped lanthnidesbased catalysts.     

Identification of specific binding proteins for a nuclear location sequence

The nuclear envelope is a selective barrier against the movement of macromolecules between the nucleus and cytoplasm. Nuclear proteins larger than relative molecular mass 20,000-40,000 are probably actively transported across the envelope through the nuclear pore complex and are directed by specific nuclear location sequences (NLS) in the proteins. NLS mediate the nuclear import of isolated nuclear proteins after microinjection into whole cells and the nuclear accumulation of chimaeric proteins or of non-nuclear proteins conjugated to synthetic peptides. The best-characterized NLS is the simian virus 40 large T-antigen sequence. We have identified two proteins of rat liver by chemical cross-linking that interact with a synthetic peptide containing this sequence: this interaction is specific for a functional NLS, is saturable, and high affinity. The binding proteins are present in a post-mitochondrial supernatant, in nuclei and in a nuclear envelope fraction, which is consistent with a role in the transport of nuclear proteins from the cytoplasm to the nucleus.     

T-cell responses to human AIDS virus in macaques immunized with recombinant vaccinia viruses

There is much interest in developing vaccines against acquired immune deficiency syndrome (AIDS), which is caused by a retrovirus termed human immunodeficiency virus (HIV). Isolates of this virus include human T-lymphotropic virus type III (HTLV-III), lymphadenopathy-associated virus (LAV), and AIDS-associated retrovirus (ARV). Several approaches towards the development of an AIDS vaccine result in the production of antibodies in subprimates. These methods involve the use of: antigens isolated from the AIDS virus; viral antigens expressed by transfected cells or by recombinant vaccinia viruses; and particular synthetic peptides of viral antigens. Because T-cell-mediated immunity (in addition to antibodies) is involved in resistance to diseases and death caused by various enveloped viruses, we sought to determine whether potential AIDS vaccines can induce T-cell responses against the AIDS virus. Here we report that immunization of non-human primates, Macaca fascicularis (macaques), with recombinant vaccinia viruses that express LAV envelope glycoproteins gp41 and gp110 results not only in the production of antibodies against the LAV envelope antigens but also in the generation of T-cells that proliferate and produce the lymphokine interleukin-2 (IL-2), in response to stimulation with purified LAV. We believe this is the first report demonstrating T-cell-mediated immunity to the virus that causes AIDS.     

Synthese der Spiroaminoketal-Gruppierung von Solanum-Alkaloiden

Summary The ring-E opened dihydro derivatives of tomatidine and soladulcidine give the corresponding N-chloroamines with N-chlorosuccinimide. Treatment of these compounds with sodium methoxide yields the spiroaminoketal alkaloids, tomatidine and soladulcidine respectively, in high yields, probably via instable C=N-unsaturated intermediates which undergo spontaneous stereospecific cyclisation.

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Solanum-Alkaloide. XIII. Mitteilung. XII. Mitteilung:K. Schreiber undH. Ripperger, Exper.16, 536 (1960).     

The influence of albumin on the electrophoretic mobility of serum lipids

Zusammenfassung Im Gegensatz zuMaurers Angaben konnte keine Wirkung des dem Puffer zugegebenen Serum-Albumins auf die elektrophoretische Wanderung von Serumphospholipiden und Cholesterin im menschlichen und tierischen Serum festgestellt werden.Maurers Befunde scheinen auf einer durch Adsorptionseffekte bewirkten Veränderung der Lipoproteine zu beruhen.

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Supported in part by a grant (H-2013) from the National Heart Institute, U.S. Public Health Service.     

Body size, organ size, and sex ratios in adult and yearling Belding ground squirrels

A five - year study of Belding ground squirrels was conducted at high altitude in the Sierra Nevada. Body weight and body length varied seasonally depending upon the fat depletion - deposition cycle, age, and sex. Adult males tended to be heavier and longer than adult females, particularly in the last half of the active season. A similar pattern was present in yearlings. Yearling squirrels were often distinguishable from adults on the basis of body size. Mean body weights were greater in adults throughout the season, and mean body lengths were greater in adults through the first half of the season. Adults also had larger internal organs than yearlings at the beginning of the season. In liver and heart this difference was sustained. Sex ratios in adults and in yearlings were 1:1 but there was considerable spatial and temporal asymmetry in distribution of the sexes. Males tended to live in areas peripheral to lush meadows occupied by females and young.       

Comparison of reproductive timing to snow conditions in wild onions and White-crowned Sparrows at high altitude

Timing of reproduction was assessed for wild onions and White-crowned Sparrows in relation to snow conditions on the same subalpine meadow in the Sierra Nevada for 21 years. Flowering date and clutch initiation date were both highly correlated with snow conditions, being later as snowpack was deeper. Interannual variation in schedule was 46 days for onions and 33 days for sparrows. There was nearly a fivefold difference in snowpack depth, and date of snow disappearance varied interannually by 72 days. Compensation for late-lying snows occurred in both species but was greater in sparrows than in onions because the nest-building behavior of sparrows was flexible. In years of deeper snow, sparrows were able to lay eggs earlier because they built more nests than usual in trees and shrubs rather than waiting for groundcover to develop.     

Calcineurin activity is required for the completion of cytokinesis

Successful completion of cytokinesis requires the spatio-temporal regulation of protein phosphorylation and the coordinated activity of protein kinases and phosphatases. Many mitotic protein kinases are well characterized while mitotic phosphatases are largely unknown. Here, we show that the Ca²⁺- and calmodulin-dependent phosphatase, calcineurin (CaN), is required for cytokinesis in mammalian cells, functioning specifically at the abscission stage. CaN inhibitors induce multinucleation in HeLa cells and prolong the time cells spend connected via an extended intracellular bridge. Upon Ca²⁺ influx during cytokinesis, CaN is activated, targeting a set of proteins for dephosphorylation, including dynamin II (dynII). At the intracellular bridge, phospho-dynII and CaN are co-localized to dual flanking midbody rings (FMRs) that reside on either side of the central midbody ring. CaN activity and disassembly of the FMRs coincide with abscission. Thus, CaN activity at the midbody plays a key role in regulating the completion of cytokinesis in mammalian cells.