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E S Zalmanzon E I Frolova B Rikhter L N Mikha?lova R L Turetskaia 《Molekuliarnaia biologiia》1979,13(2):292-308
Seven cell lines transformed by adenovirus type 5 and its DNA were obtained. It was shown that different cell lines contain the fragments of viral DNA which differ in length and number of copies per DNA of diploid cells. They contain from the left end 6% of the viral DNA to complete or almost complete viral genome. All studied cell lines were sensitive to reinfection with adenovirus type 5. They produced no virus being cocultivated with cell sensitive to the virus. No cell line was able to induce tumors even in immunosuppressed newborn rats. All cell lines formed colonies in soft agar. The level of virus-specific antigens was higher in cells that contained a large part of the viral genome. The methods used did not allow to correlate the biological properties of the transformed cells with the length and the number of copies of the integrated part of the viral genome. 相似文献
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Brooks-Kayal AR Shumate MD Jin H Rikhter TY Kelly ME Coulter DA 《Journal of neurochemistry》2001,77(5):1266-1278
Profound alterations in the function of GABA occur over the course of postnatal development. Changes in GABA(A) receptor expression are thought to contribute to these differences in GABAergic function, but how subunit changes correlate with receptor function in individual developing neurons has not been defined precisely. In the current study, we correlate expression of 14 different GABA(A) receptor subunit mRNAs with changes in the pharmacological properties of the receptor in individual hippocampal dentate granule cells over the course of postnatal development in rat. We demonstrate significant developmental differences in GABA(A) receptor subunit mRNA expression, including greater than two-fold lower expression of alpha1-, alpha4- and gamma2-subunit mRNAs and 10-fold higher expression of alpha5-mRNA in immature compared with adult neurons. These differences correlate both with regional changes in subunit protein level and with alterations in GABA(A) receptor function in immature dentate granule cells, including two-fold higher blockade by zinc and three-fold lower augmentation by type-I benzodiazepine site modulators. Further, we find an inverse correlation between changes in GABA(A) receptor zinc sensitivity and abundance of vesicular zinc in dentate gyrus during postnatal development. These findings suggest that developmental differences in subunit expression contribute to alterations in GABA(A) receptor function during postnatal development. 相似文献
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M. G. BETTS D. MITCHELL A. W. DIAMOND J. BÉTY 《The Journal of wildlife management》2007,71(7):2266-2273
ABSTRACT Roadside survey data have been used frequently to assess species occurrence and population trends and to establish conservation priorities. However, most studies using such data assume that samples are representative of either the amount of habitat or its rate of change at larger spatial scales. We tested both of these assumptions for the Breeding Bird Survey (BBS) from 1974 to 2001 in New Brunswick, Canada. Our study focused on mature forest—a cover type that we predicted would be characterized by rapid change due to human activities and that is of high ecological importance. We also sought to determine whether land cover changes adjacent to BBS routes were related to bird population trends detected in BBS data. Within all 3 time periods examined (1970s, 1980s, and 1990s), the amount of mature forest adjacent to BBS routes was significantly lower than in surrounding 1° blocks of latitude and longitude. This could be problematic for studies that use roadside data to compare the relative abundance of species. On average, mature forest declined at a rate of-1.5% per year over the 28-year study period. We detected no significant difference in the rate of change between degree blocks and BBS routes over this time span. However, in the 1970s and 1980s, mature forest declined more rapidly in degree blocks (-2.7%/yr) than adjacent to BBS routes (-0.5/yr). We also found that the BBS trend for a mature forest-associated species, blackburnian warbler (Dendroica fusca), was correlated with the trend in mature forest along BBS routes. This, combined with slower rates of mature forest change along routes in the 1970s and 1980s, suggests that BBS data may have underestimated population declines during this period. It is important that research be conducted to test for potential biases in roadside surveys caused by uneven rates of landscape change, particularly in regions characterized by rapid habitat alteration. 相似文献
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Glucagon signalling in the dorsal vagal complex is sufficient and necessary for high‐protein feeding to regulate glucose homeostasis in vivo
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Mary P LaPierre Mona A Abraham Jessica TY Yue Beatrice M Filippi Tony KT Lam 《EMBO reports》2015,16(10):1299-1307
High‐protein feeding acutely lowers postprandial glucose concentration compared to low‐protein feeding, despite a dichotomous rise of circulating glucagon levels. The physiological role of this glucagon rise has been largely overlooked. We here first report that glucagon signalling in the dorsal vagal complex (DVC) of the brain is sufficient to lower glucose production by activating a Gcgr–PKA–ERK–KATP channel signalling cascade in the DVC of rats in vivo. We further demonstrate that direct blockade of DVC Gcgr signalling negates the acute ability of high‐ vs. low‐protein feeding to reduce plasma glucose concentration, indicating that the elevated circulating glucagon during high‐protein feeding acts in the brain to lower plasma glucose levels. These data revise the physiological role of glucagon and argue that brain glucagon signalling contributes to glucose homeostasis during dietary protein intake. 相似文献
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Fomin AS Koval' OA Semenov DV Potapenko MO Kuligina EV Kit IuIa Rikhter VA 《Bioorganicheskaia khimiia》2012,38(1):92-98
Earlier we isolated and characterized human milk pro-apoptotic peptide - lactaptin and generated its engineered analog - RL2. It was shown that both lactaptin and RL2 are capable to induce apoptotic death of MCF-7 cells. In this report we have analyzed biochemical markers of RL2 induced MCF-7 apoptosis. The activation of initiator and effector caspases as well as mitochondrial membrane potential and cytoplasm membrane changes were analyzed using flow cytometry and Western-blot methods. We have found that RL2 induced apoptotic death of MCF-7 cells was accompanied by PS exposure on the plasma membrane surface. It also was shown that RL2 has induced dissipation of mitochondrial membrane potential and resulted in activation of initiator caspases 8, 9 and effector caspase 7. 相似文献
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Abstract: Dry biofilm on rocks and other substrata forms an important drought refuge for benthic algae in intermittent streams following the cessation of flow. This dry biofilm is potentially susceptible to disturbance from bushfires, including direct burning and/or scorching and damage from radiant heat, particularly when streams are dry. Therefore, damage to dry biofilms by fire has the potential to influence algal recolonization and assemblage structure in intermittent streams following commencement of flow. The influence of fire on benthic algal assemblages and recolonization was examined in intermittent streams of the Grampians National Park, Victoria, Australia, using a field survey and manipulative field experiment. The field survey compared assemblages in two intermittent streams within a recently burnt area (within 5 months of the fire) with two intermittent streams within an unburnt area. The two burnt streams were still flowing during the fire so most biofilms were not likely to be directly exposed to flames. Considerable site‐to‐site and stream‐to‐stream variation was detected during the field survey, which may have obscured potential differences attributable to indirect effects of the fire. The manipulative field experiment occurred in two intermittent streams and consisted of five treatments chosen to replicate various characteristics of bushfires that may influence dry biofilms: dry biofilm exposed directly to fire; dry biofilm exposed to radiant heat; dry biofilm exposed to ash; and two procedural controls. After exposure to the different treatments, rocks were replaced in the streams and algae were sampled 7 days after flow commenced. Differences occurred across treatments, but treatment differences were inconsistent across the two streams. For example, direct exposure to fire reduced the abundance of recolonizing algae and altered assemblage structure in both streams, while radiant heat had an effect on assemblage structure in one stream only. The manipulative field experiment is likely to have represented the intensity of a small bushfire only. Nonetheless, significant differences across treatments were detected, so these experimental results suggest that fire can damage dry biofilms, and hence, influence algal recolonization and assemblage structure in intermittent streams. 相似文献
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Priscilla TY Law Siaw Shi Boon Chenghua Hu Raymond WM Lung Grace PY Cheung Wendy CS Ho Zigui Chen Paola Massimi Miranda Thomas David Pim Lawrence Banks Paul KS Chan 《Journal of cellular and molecular medicine》2019,23(2):1517-1527
Human papillomavirus 58 (HPV58) ranks the second or third in East Asian cervical cancers. Current studies on HPV58 are scarce and focus on the prototype. Previously, we identified the three most common circulating HPV58 E7 strains contained amino acid alterations: G41R/G63D (51%), T20I/G63S (22%) and T74A/D76E (14%) respectively. Among them, the T20I/G63S variant (V1) had a stronger epidemiological association with cervical cancer. We therefore suggested that V1 possessed stronger oncogenicity than the other two variants. Here, we performed phenotypic assays to characterize and compare their oncogenicities with HPV58 E7 prototype. Our results showed that overexpression of V1 conferred a higher colony‐forming ability to primary murine epithelial cells than prototype (P < 0.05) and other variants, implicating its higher immortalising potential. Further experiments showed that both V1 and prototype enhanced the anchorage‐independent growth of NIH/3T3 cells (P < 0.001), implicating their stronger transforming power than the two other variants. Moreover, they possessed an increased ability to degrade pRb (P < 0.001), which is a major effector pathway of E7‐driven oncogenesis. Our work represents the first study to compare the oncogenicities of HPV58 E7 prototype and variants. These findings deepened our understanding of HPV58 and might inform clinical screening and follow‐up strategy. 相似文献