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21.
The crystallin synthesis of rat lens cells in cell culture systems was studied in relevance to their terminal differentiation into lens fibers. SDS-gel electrophoresis combined with several immunological techniques showed that γ-crystallin is a fiber-specific lens protein and is not localized in the epithelium of either newborn or adult lenses. When lens epithelial cells of newborn rats were cultured in vitro , α-crystaIlin was detected in many, but not all, of cells cultured for 10 days. Cells with α-crystallin gradually changed their shape into a flattened filmy form and finally differentiated into lentoid bodies. The differentiation of lentoid bodies was also found in cultures of epithelial cells obtained from adult lenses. The molecular constitution of lentoid bodies was the same as that of lens fibers in situ . The differentiation of lentoid bodies occurred successively for 5 months in cultures of lens epithelial cells. Most of the proliferating cells, however, lost α-crystallin during the culture period. Thereafter, they did not show any sign of further differentiation into lens fibers. Four clonal lines were established from these cells. One protein which is specific to the lens epithelium and the neural retina in situ (tentatively named as βu-crystallin) was maintained in all lines, suggesting that some specific properties of ocular cells remain in the lined cells.  相似文献   
22.
无花果内生真菌的分离及其鉴定   总被引:8,自引:1,他引:8  
从无花果(Ficus carica)的根、茎、叶中分离得到87株内生真菌,经显微形态特征观察鉴定为14个属,其中根部35株涉及8个属,茎部37株涉及10个属,叶部15株涉及3个属。结果表明,无花果的不同部位内生真菌的数量、分布和种群存有差异。  相似文献   
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In order to construct an anlageplan of the imaginal disc, various fragments of the wing disc from mature larvae of Sarcophaga peregrina were implanted into host larvae of the same age. The implants were metamorphosed with the host and the differentiated adult structures were analyzed.
On the basis of the results obtained from the transplanted disc fragments, a fate map of the wing disc was satisfactorily constructed.
The fate map of S. peregrina is similar to an earlier study of Drosophila , but the PAA, PWP, and AP are located in different positions from those of Drosophila .  相似文献   
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The cricket Modicogryllus siamensis Chopard shows photoperiod‐dependent changes in the duration of nymphal development: nymphs become adult within 60 days after hatching, undergoing seven moults under long‐day conditions, whereas, under short‐day conditions, nymphal development takes much longer (approximately 180 days) with an increased number of moults. Because removal of the compound eyes alters this photoperiodic response, the eyes may be involved in light detection during the photoperiodic response. The role of opsins, expressed in the compound eye, is examined in the present study with reference to the photoperiodic response. Molecular cloning identifies cDNAs of three opsins, opsin‐Ultra Violet (Ms'op‐UV), opsin‐Blue (Ms'op‐B) and opsin‐Long Wave (Ms'op‐LW), and in situ hybridization reveals that the opsin genes are expressed in specific regions of the compound eye in a gene‐specific manner. RNA interference (RNAi) technology using the opsin genes results in a partial disruption in the long‐day responses; most of the treated crickets showed eight or more moults and up to 23.5% show a prolonged nymphal period that is typical of short‐day responses. Under short‐day conditions, op‐UV RNAi crickets show earlier adult development, whereas no distinct alterations are observed in op‐B and op‐LW RNAi insects. The results suggest that the opsin genes may play differential roles in the photoperiodic response in the cricket and that the results can be at least partially explained in terms of the external coincidence model of photoperiodic time measurement.  相似文献   
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The photoperiodic response of diapause induction is studied in females of five subtropical and warm‐temperate zone populations of Nezara viridula (L.) (Heteroptera: Pentatomidae) in Japan (26.4–34.7°N; 127.4–135.7°E). Laboratory tests at 25 °C demonstrate that both warm‐temperate and subtropical populations have pronounced photoperiodic responses of adult diapause induction. Under short‐day conditions (LD 10 : 14 h), 73–100% of females enter diapause, whereas, under long‐day conditions (LD 15 : 9 h), 87–100% of females are nondiapause and reproduce. When the critical photoperiod for diapause induction is plotted against the latitude of origin of each population, the data points do not show the expected tendency of increasing critical photoperiod northwards but, instead, vary between 12 h 15 min and 13 h 30 min. It is suggested that adults from different populations of such a highly migratory species move often among subtropical islands (by themselves or being assisted by typhoons), thus constantly destabilizing the photoperiodic responses. Although important for general synchronization of seasonal development in the tropics and subtropics, winter diapause might not be so critical for survival in mild winters in these zones. Such circumstances might make the selective pressure over the photoperiodic response less severe in the tropics and subtropics than in the temperate zone. It is suggested that the current climate warming might contribute to this situation as well by promoting polewards migrations and lessening the selective pressure of overwintering conditions.  相似文献   
29.
In 2009 the WPA President established a Task Force that was to examine available evidence about the stigmatization of psychiatry and psychiatrists and to make recommendations about action that national psychiatric societies and psychiatrists as professionals could do to reduce or prevent the stigmatization of their discipline as well as to prevent its nefarious consequences. This paper presents a summary of the Task Force’s findings and recommendations. The Task Force reviewed the literature concerning the image of psychiatry and psychiatrists in the media and the opinions about psychiatry and psychiatrists of the general public, of students of medicine, of health professionals other than psychiatrists and of persons with mental illness and their families. It also reviewed the evidence about the interventions that have been undertaken to combat stigma and consequent discrimination and made a series of recommendations to the national psychiatric societies and to individual psychiatrists. The Task Force laid emphasis on the formulation of best practices of psychiatry and their application in health services and on the revision of curricula for the training of health personnel. It also recommended that national psychiatric societies establish links with other professional associations, with organizations of patients and their relatives and with the media in order to approach the problems of stigma on a broad front. The Task Force also underlined the role that psychiatrists can play in the prevention of stigmatization of psychiatry, stressing the need to develop a respectful relationship with patients, to strictly observe ethical rules in the practice of psychiatry and to maintain professional competence.  相似文献   
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Mesocotyl elongation in paddy rice seedlings of the japonicatype was markedly stimulated by high temperature pre-treatmentof seeds. Examination of the number of parenchyma cells perone cell layer in longitudinal sections of mesocotyl revealedthat stimulation may be mainly caused by cell multiplication. (Received February 24, 1970; )  相似文献   
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