Tin compounds are being used increasingly inin industry and in medicine. There have been relatively few studing term biological effects of this metal, although acute effects hcumented. In this report we describe experiments which show thastannous chloride, is readily taken up by human white blood cellsan cause damage to DNA. Damage was detected in WBC after e-50 μM tin(II) for 30 min at either 0°C or 37°C. The amount oserved was more extensive than that produced by exposure of nolar amounts of chromium(VI), a known carcinogen and DNAagent. Additional indication of cellular damage is that exposmn lymphocytes or mouse splenocytes to tin(II) interfered with theio be stimulated by the polyvalent mitogen concanavalin A (Con A). rast, tin(IV) was not taken up by cells, did not cause DNA damage nor dinhibit stimulation of DNA synthesis in cells that were exposed to Con A. 相似文献
A full species composition of anemonefishes (Pomacentridae, Amphiprioninae) and their host sea anemones (Cnidaria, Actiniaria) from reefs of Phu Quy and Con Son Islands (off South Vietnam) and An Thoi Islands (northeastern Gulf of Thailand) is presented for the first time. A comparison of the faunas of anemonefishes and their host sea anemones is conducted in the coastal waters of Vietnam and adjacent waters. The presence of intermittent ranges of the anemonefishes in the coastal waters of Vietnam is demonstrated. For example, the ranges of two species, Amphiprion clarkii and A. frenatus, include the coastal waters of Vietnam, excluding the Gulf of Thailand, where they are not found even at the eastern border of the gulf. A. perideraion is absent in the Gulf of Tonkin, but it is distributed to the south along the entire coastal zone of Vietnam, including the Gulf of Thailand. In the coastal waters of Vietnam, A. sandaracinos is distributed only between the Gulf of Tonkin and Gulf of Thailand. A. polymnus is reliably indicated in the coastal waters of Vietnam between 12°50′ and 9°54′ N, but, most likely, its range is continuous along the entire Vietnamese coast. The richness of species composition of host sea anemones decreases (from nine to three species) in the southern direction, from Central Vietnam to the eastern border of the Gulf of Thailand. 相似文献
Highlights? A phase map of cell fate patterns is built as a function of signaling pathway dose ? The vulva system can buffer a 4-fold variation in mean lin-3/egf mRNA number ? The major role of LIN-12/Notch in the vulva is to promote the 2° fate ? Inhibition of 1° fate by LIN-12 is important when lin-3 dose is mildly increased 相似文献
Cheilopogon melanurus, found for the first time in the central part of the North Atlantic (26°34′6 N 33°55′2 W), and C. heterurus from the eastern part of the Mediterranean Sea (Mahmutlar, Alanya, Turkey) are described. C. heterurus is widely distributed in the eastern part of the Mediterranean Sea occurring here in all seasons. 相似文献
Highlights? Precise interaction mapping using substrate analogs and X-ray crystallography ? Amidation of 5′-amino-5′-deoxy-adenosine is promoted by crystallized LmNADK1 ? Structures guide fragment bridging to design a new antistaphylococcal compound 相似文献
Highlights? A mouse model of a hemizygous 22q11.2 deletion shows over 50% reduction of miR-185 ? Mirta22 is a miR-185 target and a major effector of the 22q11.2 miRNA dysregulation ? Mirta22 is a prenatally biased neuronal inhibitor located in the Golgi apparatus ? Altered levels of miR-185 and Mirta22 affect dendrite and spine development 相似文献
The site of Morro Grande, situated in the Araruama region, southeastern Brazil (22º47′07″S, 42º21′49″W), is in the Atlantic rainforest phytogeographical domain. It is attributed to proto-Tupinambá agriculturalist and ceramicist populations, recognized by their typical polychrome ceramics. Four periods of occupation were identified at this site: (1) 3,220–2,840 cal b.p.; (2) 3,000–2,150 cal b.p.; (3) 1,820–1,390 cal b.p.; and (4) c. 750 cal. b.p. Analysis of 3,908 charcoal fragments from the three earlier periods has allowed the identification of 78 taxa and 29 plant families. This work demonstrates the permanence of the Atlantic rainforest in the region between 3,220 and 1,390 cal b.p., confirming previous palaeoenvironmental studies in southeastern and southern Brazil. The existence of mature forests is demonstrated; however, firewood was collected mainly from secondary vegetation, probably in the area surrounding the settlement or from cultivated land. These results provide further evidence of human influence on Neotropical rainforests. Creation of secondary environments, however, did not result in irreversible damage to local biodiversity, since the forest tended to regenerate after the clearings were abandoned. Analysis of charcoal concentrated in features allowed the identification of ritual funerary hearths, as well as of a probable specialized feature for firing ceramics. This evidence affords new perspectives for the archaeological interpretation of the funerary ritual and way of life of proto-Tupinambá people. 相似文献
