Rapid induction of pluripotency genes after exposure of human somatic cells to mouse ES cell extracts

The expression of 4 pluripotency genes (Oct4, Sox2, c-Myc and Klf4) in mouse embryonic fibroblasts can reprogramme them to a pluripotent state. We have investigated the expression of these pluripotency genes when human somatic 293T cells are permeabilized and incubated in extracts of mouse embryonic stem (ES) cells. Expression of all 4 genes was induced over 1–8 h. Gene expression was associated with loss of repressive histone H3 modifications and increased recruitment of RNA polymerase II at the promoters. Lamin A/C, which is typically found only in differentiated cells, was also removed from the nuclei. When 293T cells were returned to culture after exposure to ES cell extract, the expression of the pluripotency genes continued to rise over the following 48 h of culture, suggesting that long-term reprogramming of gene expression had been induced. This provides a methodology for studying the de-differentiation of somatic cells that can potentially lead to an efficient way of reprogramming somatic cells to a pluripotent state without genetically altering them.     

The role of nitric oxide in cancer

Nitric oxide (NO) is a pleiotropic regulator, critical to numerous biological processes, including va-sodilatation, neurotransmission and macrophage-mediated immunity. The family of nitric oxide synthases (NOS) comprises inducible NOS (iNOS), endothelial NOS (eNOS), and neuronal NOS (nNOS). Interestingly, various studies have shown that all three isoforms can be involved in promoting or inhibiting the etiology of cancer. NOS activity has been detected in tumour cells of various histogenetic origins and has been associated with tumour grade, proliferation rate and expression of important signaling components associated with cancer development such as the oestrogen receptor. It appears that high levels of NOS expression (for example, generated by activated macrophages) may be cytostatic or cytotoxic for tumor cells, whereas low level activity can have the opposite effect and promote tumour growth. Paradoxically therefore, NO (and related reactive nitrogen species) may have both genotoxic and angiogenic pro     

Diet of wild chimpanzees (Pan troglodytes verus) at Mt. Assirik,Senegal: I. Composition

The composition of the diet of a savanna-living population of wild chimpanzees (Pan troglodytes verus) at Mt. Assirik in Senegal is presented. The study site had a prolonged dry season, high temperatures, and vegetation dominated by grasses. Data came from direct observation, fecal specimens, and feeding traces; thus, strict criteria for acceptance of the indirect data were specified. Composition of diet was given in terms of species and family of prey, parts eaten, life-form, type of habitat, and criteria for inclusion. Forty-three species of plants with 60 parts were eaten; mostly fruits, from trees, in woodland. Nine species of animal prey were eaten, mostly social insects. An additional 41 species of plants with 53 parts were classed as likely to be eaten by chimpanzees, mostly on the grounds of their being eaten by sympatric anthropoids. Overall, the diet of the apes at Mt. Assirik resembles that of this species elsewhere in Africa, but the size of the dietary repertoire seems small and the proportion of low-quality foodstuffs high. The latter are mostly time-consuming to collect or tedious to obtain or process, and include underground storage organs.     

Hrdlicka revisited (external auditory canal exostoses)

To determine possible matter of opinion as to the existence of exostoses in the outer ear canals of Indian skulls from Dakota as an explanation for the marked difference in incidence of these tumors found by Hrdlicka and by us in previous studies, we have examined skeletal specimens reportedly seen by Hrdlicka, independently, and compared his and our results. The Smithsonian-Mobridge skulls both in Hrdlicka's and our opinion show definitely more exostoses than are found in other South Dakota Indian skeletal material we have examined. Our results here suggest a 5–6% difference attributable to opinion of the examiner. Reasons for the dissimilarity in frequency of exostoses between the Smithsonian-Mobridge skulls and other Dakota Indian skeletal collections are advanced.     

Lack of hand preference in wild Hanuman langurs (Presbytis entellus)

Although there is a vast literature on laterality of hand-use in nonhuman primates, the Colobinae have been notably overlooked. Ten manual activities of differing complexity were studied in five male and five female adult Hanuman langurs (Presbytis entellus) from a well habituated, wild population at Ramnagar, in southern Nepal. The activities recorded were carry, eat, hit, hold, idle, manipulate, reach, retrieve, self-groom and social groom. This study aimed to examine handedness across tasks and across subjects in a natural population. The overall result was a lack of preference for subjects and patterns. Only in the eating activity did four individuals show significant hand preference, though they were not unidirectional. Eat seemed to be loosely associated with hold due to the requirements of the strata which the monkeys utilize. These results suggest that hand use is unlateralized in P. entellus. Those individuals exhibiting some hand preferences can be viewed as statistical exceptions or perhaps subject to experiential differences. The results are discussed in terms of their evolutionary significance and methodological implications. Am J Phys Anthropol 103:455–461, 1997. © 1997 Wiley-Liss, Inc.