Zinc iodide-osmium tetroxide reactive substances in the matrix of granulated vesicles in the rat pineal nerves

Resumen Se demuestra que la reserpina depleciona los componentes de las vesículas sinápticas de los nervios pineales de la rata revelables por la mezcla de yoduro de zinc-tetróxido de osmio a 4°C durante dos horas y a 20°C durante 15 h mientras que lap-CPA sólo depleciona los componentes revelables a 4°C durante 2 h.

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This work has been supported by grants from the Universidad Nacional de Buenos Aires, the Consejo Nacional de Investigaciones Cientificas y Técnicas, Argentina and the National Institutes of Health (Nas. 2 ROI NS 06953-07 NEUA), USA.

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We are grateful to MissM. López for her skillful technical assistance.     

The diet of Australopithecus sediba

Specimens of Australopithecus sediba from the site of Malapa, South Africa (dating from approximately 2 million years (Myr) ago) present a mix of primitive and derived traits that align the taxon with other Australopithecus species and with early Homo. Although much of the available cranial and postcranial material of Au. sediba has been described, its feeding ecology has not been investigated. Here we present results from the first extraction of plant phytoliths from dental calculus of an early hominin. We also consider stable carbon isotope and dental microwear texture data for Au. sediba in light of new palaeoenvironmental evidence. The two individuals examined consumed an almost exclusive C(3) diet that probably included harder foods, and both dicotyledons (for example, tree leaves, fruits, wood and bark) and monocotyledons (for example, grasses and sedges). Like Ardipithecus ramidus (approximately 4.4 Myr ago) and modern savanna chimpanzees, Au. sediba consumed C(3) foods in preference to widely available C(4) resources. The inferred consumption of C(3) monocotyledons, and wood or bark, increases the known variety of early hominin foods. The overall dietary pattern of these two individuals contrasts with available data for other hominins in the region and elsewhere.     

High-valent organometallic copper and palladium in catalysis

Copper and palladium catalysts are critically important in numerous commercial chemical processes. Improvements in the activity, selectivity and scope of these catalysts could drastically reduce the environmental impact, and increase the sustainability, of chemical reactions. One rapidly developing strategy for achieving these goals is to use 'high-valent' organometallic copper and palladium intermediates in catalysis. Here we describe recent advances involving both the fundamental chemistry and the applications of these high-valent metal complexes in numerous synthetically useful catalytic transformations.     

RNAi-mediated gene silencing in non-human primates

The opportunity to harness the RNA interference (RNAi) pathway to silence disease-causing genes holds great promise for the development of therapeutics directed against targets that are otherwise not addressable with current medicines. Although there are numerous examples of in vivo silencing of target genes after local delivery of small interfering RNAs (siRNAs), there remain only a few reports of RNAi-mediated silencing in response to systemic delivery of siRNA, and there are no reports of systemic efficacy in non-rodent species. Here we show that siRNAs, when delivered systemically in a liposomal formulation, can silence the disease target apolipoprotein B (ApoB) in non-human primates. APOB-specific siRNAs were encapsulated in stable nucleic acid lipid particles (SNALP) and administered by intravenous injection to cynomolgus monkeys at doses of 1 or 2.5 mg kg(-1). A single siRNA injection resulted in dose-dependent silencing of APOB messenger RNA expression in the liver 48 h after administration, with maximal silencing of >90%. This silencing effect occurred as a result of APOB mRNA cleavage at precisely the site predicted for the RNAi mechanism. Significant reductions in ApoB protein, serum cholesterol and low-density lipoprotein levels were observed as early as 24 h after treatment and lasted for 11 days at the highest siRNA dose, thus demonstrating an immediate, potent and lasting biological effect of siRNA treatment. Our findings show clinically relevant RNAi-mediated gene silencing in non-human primates, supporting RNAi therapeutics as a potential new class of drugs.     

The feasibility of making short-term migration estimates

Short-term migration, that is stays of less than 12 months, has received particular attention recently from both national and local level users of population statistics. This interest is part of the wider interest shown in increasing levels of long-term migration statistics in recent years. This article is an initial assessment by ONS of the potential to produce short-term migration estimates for England and Wales, and the challenges faced in doing so. Central to these challenges is the question of how short-term migration should be defined. In addition, illustrative estimates of short-term migration based on the International Passenger Survey (IPS) are provided. These illustrative estimates, along with associated standard errors, are provided at both national and regional levels using a number of definitional bases.     

Genome-wide genetic analysis of polyploidy in yeast

Polyploidy, increased sets of chromosomes, occurs during development, cellular stress, disease and evolution. Despite its prevalence, little is known about the physiological alterations that accompany polyploidy. We previously described 'ploidy-specific lethality', where a gene deletion that is not lethal in haploid or diploid budding yeast causes lethality in triploids or tetraploids. Here we report a genome-wide screen to identify ploidy-specific lethal functions. Only 39 out of 3,740 mutations screened exhibited ploidy-specific lethality. Almost all of these mutations affect genomic stability by impairing homologous recombination, sister chromatid cohesion, or mitotic spindle function. We uncovered defects in wild-type tetraploids predicted by the screen, and identified mechanisms by which tetraploidization affects genomic stability. We show that tetraploids have a high incidence of syntelic/monopolar kinetochore attachments to the spindle pole. We suggest that this defect can be explained by mismatches in the ability to scale the size of the spindle pole body, spindle and kinetochores. Thus, geometric constraints may have profound effects on genome stability; the phenomenon described here may be relevant in a variety of biological contexts, including disease states such as cancer.