Osmotic stress is one of the most significant natural abiotic stresses that occur in the intertidal zones. Seaweeds may physiologically acclimate to changing osmolarity by altering their transcriptome. Here, we investigated the transcriptomic changes of Gracilaria changii (B. M. Xia et I. A. Abbott) I. A. Abbott, J. Zhang et B. M. Xia in response to hyper- and hypoosmotic stresses using a cDNA microarray approach. Microarray analysis revealed that 199 and 200 genes from ∼3,300 genes examined were up- and down-regulated by >2-fold in seaweed samples treated at 50 parts per thousand (ppt) artificial seawater (ASW) compared with those at 30 ppt ASW, respectively. The number of genes that were up- and down-regulated by >2-fold in seaweed samples treated at 10 ppt ASW compared with those at 30 ppt ASW were 154 and 187, respectively. A majority of these genes were only differentially expressed under hyper- or hypoosmotic conditions, whereas 67 transcripts were affected by both stresses. The findings of this study have shed light on the expression profiles of many transcripts during the acclimation of G. changii to hyperosmotic and hypoosmotic conditions. This information may assist in the prioritization of genes to be examined in future studies.
An experiment was conducted to determine the effects of 2 types of housing systems and early age feed restriction on heat shock protein (hsp) 70 expression and blood parameters in broiler chickens subjected to road transportation. On d 1, female chicks were housed either in windowless environmentally controlled chambers (temperature was set at 32 degrees C on d 1 and gradually reduced to 23 degrees C by d 21; CH) or in conventional open-sided houses (OH) with cyclic temperatures (minimum, 24 degrees C; maximum, 34 degrees C). Equal number of chicks from each housing system were subjected to either ad libitum feeding or 60% feed restriction on d 4, 5, and 6 (FR). On d 42, all of the birds were crated and transported for 6 h. Birds raised in OH had smaller increases in heterophil:lymphocyte ratios and plasma corticosterone concentrations than those of CH. Subjecting birds to FR dampened heterophil:lymphocyte ratios and corticosterone reactions to transportation. After 4 h of transportation, the OH birds had greater hsp 70 expression than their CH counterparts. Within the CH, the FR chicks showed higher hsp 70 density than those of the ad libitum-fed group. Except for glucose, housing system had a negligible effect on serum levels of cholesterol, potassium, and chloride. Collectively, the results suggest that the improved tolerance to transport stress in OH and FR chicks could be associated with better hsp 70 expression.
Two hundred thirty-five 1-d-old broiler chickens showing short or long tonic immobility responses were classified as low fear (LF) or high fear (HF) responders, respectively. On d 41, they were subjected to either crating or heat challenge (34 +/- 1 degrees C) for 3 h and its effect on plasma corticosterone concentration, heterophil/lymphocyte ratios, and heat shock protein (HSP) 70 expression in brain tissue were determined. Crating and heat exposure elevated heterophil/lymphocyte ratios in both LF and HF birds. Circulating corticosterone, however, was greater in HF than LF birds after crating and heat challenge. Although differences between fear responder group for HSP 70 were negligible before heat challenge, after 3 h of heat exposure, the response was greater for the HF than the LF group. Both LF and HF showed similar increases in HSP 70 after crating.
Chronic stress has been shown to cause oxidative damage in the central nervous system. Although stress-induced impairments in learning and memory have been studied extensively, very few studies have investigated possible ways to prevent their ill effects. The present work was designed to study the protective effects of ascorbic acid in memory loss induced by chronic restraint stress.