Effects of simulated light regimes on gene expression in Antarctic krill (Euphausia superba Dana)

first_imgA change in photoperiod has been implicated in triggering a transition from an active to a quiescent state in Antarctic krill. We examined this process at the molecular level, to identify processes that are affected when passing a photoperiodic threshold. Antarctic krill captured in the austral autumn were divided into two groups and immediately incubated either under a photoperiod of 12 h light:12 h darkness (LID), simulating the natural light cycle, or in continuous darkness (DID), simulating winter. All other conditions were kept identical between incubations. After 7 days of adaptation, krill were sampled every 4h over a 24h period and frozen. Total RNA was extracted from the heads and pooled to construct a suppression subtractive hybridisation library. Differentially expressed sequences were identified and annotated into functional categories through database sequence matching. We found a difference in gene expression between LD and DD krill, with LID krill expressing more genes involved in functions such as metabolism, motor activity, protein binding and various other cellular activities. Eleven of these genes were examined further with quantitative polymerase chain reaction analyses, which revealed that expression levels were significantly higher in LD krill. The genes affected by simulated photoperiodic change are consistent with known features of quiescence, such as a slowing of moult rate, a lowering of activity levels and a reduction in metabolic rate. The expression of proteases involved in apolysis, where the old cuticle separates from the epidermis, showed particular sensitivity to photoperiod and point to the mechanism by which moult rate is adjusted seasonally. Our results show that key processes are already responding at the molecular level after just 7 days of exposure to a changed photoperiodic cycle. We propose that krill switch rapidly between active and quiescent states and that the photoperiodic cycle plays a key role in this process. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.last_img read more

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Recovery of city’s first COVID-19 patient hailed

first_imgThesedroplets also land on objects and surfaces around the person. Other people thencatch COVID-19 by touching these objects or surfaces, then touching their eyes,nose or mouth. She made a complete recovery, heannounced. “We’re in this together. We willcontinue to fight this battle, protect the community and observe healthcarestandards in taking care of our patient partners,” TMC added. The Medical City (TMC) in Molodistrict confirmed that the woman was discharged from the hospital on April 3. A repeat test showed her to benegative of SARS-CoV-2, the virus which causes COVID-19, according to TMC chiefexecutive officer Dr. Felix Ray Villa. ILOILO City – In Western Visayas, twopersons with coronavirus disease 2019 (COVID-19) have so far recovered. TMC described her as “the firstCOVID-19 survivor of Panay Island” and a milestone not only for the hospitalbut to the Ilonggo community. SCREENSHOT FROM TMC ILOILO FACEBOOK PAGE He was hospitalized on March 6. Mostpeople (about 80 percent) recover from the disease without needing specialtreatment, according to the World Health Organization (WHO). center_img Themost common symptoms of COVID-19 are fever, tiredness, and dry cough. “We acknowledge our healthcare workers, critical team and the entire TMC Iloilo workforce for the bravery and kindness shown during these challenging times,” a statement from TMC read. The hospital thanked city andprovincial governments of Iloilo, private companies, organizations, and privateindividuals who gave support. The first to make a complete recoveryfrom COVID-19 was the region’s first patient – a 56-year-old male from BacolodCity with a travel history to London and Manila. Olderpeople, however, and those with underlying medical problems like high bloodpressure, heart problems or diabetes, are more likely to develop seriousillness, said WHO. Peoplecan catch COVID-19 from others who have the virus. The disease can spread fromperson to person through small droplets from the nose or mouth which are spreadwhen a person with COVID-19 coughs or exhales. The latest to recuperate was a 61-yearold female – this city’s first and the region’s third COVID-19 case. Somepatients may have aches and pains, nasal congestion, runny nose, sore throat ordiarrhea. These symptoms are usually mild and begin gradually. Some peoplebecome infected but don’t develop any symptoms and don’t feel unwell./PNlast_img read more

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