Phase Shifts of the Circadian Locomotor Rhythm Induced by Pigment-Dispersing Factor in the Cricket Gryllus bimaculatus

Pigment-dispersing factors (PDFs) are octadeca-peptides widely distributed in insect optic lobes and brain. In this study, we have purified PDF and determined its amino acid sequence in the cricket Gryllus bimaculatus. Its primary structure was NSEIINSLLGLPKVLNDA-NH2, homologous to other PDH family members so far reported. When injected into the optic lobe of experimentally blinded adult male crickets, Gryllus-PDF induced phase shifts in their activity rhythms in a phase dependent and dose dependent manner. The resulted phase response curve (PRC) showed delays during the late subjective night to early subjective day and advances during the mid subjective day to mid subjective night. The PRC was different in shape from those for light, serotonin and temperature. These results suggest that PDF plays a role in phase regulation of the circadian clock through a separate pathway from those of other known phase regulating agents

Phase Shifts of the Circadian Locomotor Rhythm Induced by Pigment-Dispersing Factor in the Cricket Gryllus bimaculatus

ABSTRACT -Pigment-dispersing factors (PDFs) are octadeca-peptides widely distributed in insect optic lobes and brain. In this study, we have purified PDF and determined its amino acid sequence in the cricket Gryllus bimaculatus . Its primary structure was NSEIINSLLGLPKVLNDA-NH 2 , homologous to other PDH family members so far reported. When injected into the optic lobe of experimentally blinded adult male crickets, Gryllus -PDF induced phase shifts in their activity rhythms in a phase dependent and dose dependent manner. The resulted phase response curve (PRC) showed delays during the late subjective night to early subjective day and advances during the mid subjective day to mid subjective night. The PRC was different in shape from those for light, serotonin and temperature. These results suggest that PDF plays a role in phase regulation of the circadian clock through a separate pathway from those of other known phase regulating agents

ENVIRONMENTAL AWARENESS OF PEOPLE AT DIFFERENT OCCUPATIONAL LEVELS: A CASE STUDY ON THE FARMERS, HOSPITAL AND INDUSTRIAL WORKERS, BANGLADESH

The study was conducted to find out the level of environmental awareness of the farmers, hospital and industrial workers at Tangail Sadar Upazila in Tangail District, Bangladesh. The study included a questionnaire survey on a total of 390 respondents including 130 farmers, 130 hospital workers and 130 industrial workers in relation to their perception and awareness about several global and local environmental issues. Among the respondents 48.4% farmers were illiterate while all of the hospital and industrial workers passed the minimum level of education i.e. primary level. Only 12.1% and 6.6% of the hospital and industrial workers, respectively, completed their graduation whereas no farmer was found who completed the graduation. The study showed that the extent of environmental awareness varies among people at different occupational levels. The level of environmental awareness among the hospital workers was quite satisfactory than other groups of respondents. Industrial workers have comparatively better idea as their level of education was quite better than the farmers. Moreover, 33.6%, 58.2% and 35.6% of the farmers, hospital and industrial workers, respectively, participated in different awareness rising programs. The result of the study depicted that the hospital workers are much more conscious about different environmental issues than the others as their educational background was comparatively higher and also as they have participated comparatively in large number of environmental programs