RESUMEN
Helicoverpa armigera (Hübner) exhibits a facultative pupal diapause, which depends on temperature and photoperiod. Pupal diapause is induced at 20 degrees C by short photoperiods and inhibited by long photoperiods during the larval stage. However, in some pupae (35% of males and 57% of females) of a non-selected field population from Okayama Prefecture (34.6 degrees N), diapause is not induced by short photoperiods. In the present experiment, the importance of temperature for diapause induction was studied in the non-diapausing strain, which was selected from such individuals reared at 20 degrees C under a short photoperiod of 10L:14D. Furthermore, the sensitive stage for thermal determination of pupal diapause was determined by transferring larvae of various instars and pupae between 20 degrees C and 15 degrees C. Diapause was induced by 15 degrees C without respect to photoperiod. When larvae or pupae reared from eggs at 20 degrees C under a short or a long photoperiod were transferred to 15 degrees C in the periods of the middle fifth instar to the first three days after pupation, the diapause induction rate was significantly reduced in both males and females, especially in females. In contrast, when larvae or pupae reared at 15 degrees C were transferred to 20 degrees C in the same periods, diapause was induced in males, but not in females. However, the diapause induction rate of pupae transferred to 20 degrees C on the fourth day after pupation was significantly increased in females. The results show that temperature is the major diapause cue in the photoperiod-insensitive strain and the periods of middle fifth larval instar to early pupal stage are the thermal sensitive stages for pupal diapause induction with some different responses to temperatures between males and females in H. armigera.
Asunto(s)
Frío , Mariposas Nocturnas/crecimiento & desarrollo , Animales , Femenino , Japón , Larva/crecimiento & desarrollo , Masculino , Fotoperiodo , Pupa/crecimiento & desarrolloRESUMEN
Gene expressions of acclimatized and non-acclimatized diapausing larvae were examined in Chilo suppressalis using a subtraction technique. A gene encoding a methionine-rich storage protein, CsSP1, was cloned and its complete cDNA sequence was determined. Potentially, CsSP1 encoded a 758-amino acid protein, with a calculated molecular weight of 88.8 kDa. The expression level of CsSP1 was higher in nondiapausing larvae than in diapausing ones. The CsSP1 expression was up-regulated in diapausing larvae when the temperature of cold acclimation was shifted to 5 degrees C. The up-regulated level was maintained at 40 days after incubation at 5 degrees C. In nondiapausing larvae, CsSP1 expression was down-regulated when the temperature was below developmental zero. Involvement of CsSP1 in diapause, cold tolerance acquisition and postdiapause development in C. suppressalis is discussed.
Asunto(s)
Aclimatación , Frío , Genes de Insecto/genética , Lepidópteros/fisiología , Metamorfosis Biológica/genética , Oryza/parasitología , Tallos de la Planta/parasitología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Southern Blotting , Clonación Molecular , Femenino , Regulación de la Expresión Génica , Proteínas de Insectos/química , Proteínas de Insectos/genética , Larva/crecimiento & desarrollo , Larva/metabolismo , Lepidópteros/genética , Lepidópteros/crecimiento & desarrollo , Metionina/análisis , Datos de Secuencia Molecular , ARN Mensajero/genética , ARN Mensajero/metabolismo , Alineación de SecuenciaRESUMEN
To investigate the mechanism of synovial hyperplasia by human T-lymphotropic virus type I (HTLV-I) infection, the enzymatic activity of telomerase and expression of telomerase-related factors in HTLV-I infected synoviocytes were examined. Cultured synoviocytes obtained from four patients with osteoarthritis (OA) and four with traumatic joint disease (TJD) were infected by HTLV-I. Telomerase activity was detected by telomeric repeat amplification protocol (TRAP) assay. Expression of telomerase-related mRNAs such as telomerase reverse transcriptase (hTERT), telomerase RNA component (hTERC), and telomeric repeat binding factor 2 (TRF2) were also examined. Telomerase activity was detected in all HTLV-I-infected synoviocytes but not in uninfected synoviocytes. A remarkable induction of hTERT mRNA was observed in four of eight HTLV-I-infected synoviocytes, whereas expressions of hTERC, TRF2, and TEP-1 mRNAs were not changed. Our results clearly demonstrate that HTLV-I upregulates telomerase activity in synoviocytes probably via upregulation of hTERT activity. These findings suggest that telomerase activation in synoviocytes has an important role in upregulated proliferative activity of HAAP synoviocytes.
Asunto(s)
Virus Linfotrópico T Tipo 1 Humano/fisiología , Membrana Sinovial/virología , Telomerasa/biosíntesis , Proteínas Portadoras/biosíntesis , Proteínas Portadoras/genética , División Celular , Células Cultivadas , Técnicas de Cocultivo , Cartilla de ADN/química , Proteínas de Unión al ADN/biosíntesis , Proteínas de Unión al ADN/genética , Humanos , Osteoartritis de la Rodilla/patología , ARN , ARN Largo no Codificante , ARN Mensajero/metabolismo , ARN no Traducido/biosíntesis , ARN no Traducido/genética , Proteínas de Unión al ARN , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Membrana Sinovial/enzimología , Telomerasa/genética , Proteína 2 de Unión a Repeticiones Teloméricas , Regulación hacia ArribaRESUMEN
To investigate the mechanism of persistent proliferation of rheumatoid arthritis (RA) synoviocytes in situ, we examined the activity of telomerase enzyme and the expression of telomerase related factors in cultured synoviocytes. Cultured synoviocytes obtained from patients with rheumatoid arthritis (n = 29), osteoarthritis (OA, n = 18), and traumatic joint disease (TJD, n = 4) were examined. Telomerase activity was detected by TRAP (telomeric repeat amplification protocol) assay, and 12 out of 29 samples of synoviocytes (41%) from RA patients showed a positive telomerase activity, whereas none of the samples from OA and TJD patients showed this activity. Results were confirmed by PCR-ELISA. The telomerase activity was enhanced by basic fibroblast growth factor (bFGF). The mRNA expression of telomerase related factors, such as hTERC, TRF2, and TEP-1, showed no difference between RA and OA synoviocytes. Our results suggest that telomerase is activated in rheumatoid synoviocytes, and that bFGF upregulates the activity of this enzyme in RA synoviocytes.
Asunto(s)
Artritis Reumatoide/fisiopatología , Factor 2 de Crecimiento de Fibroblastos/farmacología , Membrana Sinovial/fisiopatología , Telomerasa/metabolismo , Artritis Reumatoide/enzimología , Proteínas Portadoras/genética , División Celular/fisiología , Células Cultivadas , Proteínas de Unión al ADN/genética , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Humanos , Deformidades Adquiridas de la Articulación/enzimología , Deformidades Adquiridas de la Articulación/fisiopatología , Persona de Mediana Edad , Osteoartritis/enzimología , Osteoartritis/fisiopatología , ARN Mensajero/metabolismo , Proteínas de Unión al ARN , Membrana Sinovial/enzimología , Telomerasa/efectos de los fármacos , Proteína 2 de Unión a Repeticiones TeloméricasRESUMEN
The heteropteran Pyrrhocoris apterus (L.) does not survive freezing of its body fluids; there is a good correlation between values of survival at subzero temperatures and the supercooling point (SCP), i.e., the temperature at which body fluids start to freeze. The decrease of the SCP and thus the increase in cold hardiness is regulated by photoperiod and temperature. The relative importance of these factors depends on the physiological state of the insect. The SCP is about -7°C at the onset of prediapause and a decrease of about 4-5°C is associated with the development of the diapause syndrome in adults; these processes both are induced by a short-day photoperiod with temperature playing a secondary role. The induction of the diapause syndrome is a prerequisite for the subsequent decrease of the SCP by about 5-6°C during cold acclimation. An intermediate temperature of 15°C, or fluctuating outdoor temperatures and short-day photoperiods, are more suitable for the decrease of SCP than 5°C in continuous darkness. The sensitivity to photoperiod gradually disappears during the development of diapause; after the termination of diapause around the winter solstice the SCP irreversibly increases at a high temperature of 26°C even if exposed to a short-day photoperiod. The SCPs of hemolymph, gut, fat body, and gonads were compared to whole-body SCP. The gut was identified as the primary site of ice nucleation because its SCP value was very similar to the value for the whole body in both short-day and long-day insects. The SCPs of other organs, including the hemolymph, were always lower than the whole body SCP. Food was not a source of ice nucleating agents because the SCP of freshly ecdysed adults remained high after 2 weeks of starvation. In contrast, feeding was a prerequisite for the decrease of the SCP during prediapause. In postdiapause insects, the SCP increased at high temperatures in spite of the absence of food.
RESUMEN
The effects of culture conditions on the ice nucleus production of Fusarium moniliforme var. subglutinans isolated from the gut of larvae of the rice stem borer (Chilo suppressalis Walker) were examined. The ice nucleus production was only affected by cultivation temperature and pH: the optimum temperature and pH were 15 degrees C to 20 degrees C and 4.0 to 6.0, respectively.