Changes in embryonic development,juvenile growth and physiological adaptation of the cuttlefish Sepia pharaonis in response to photoperiod manipulation

Photoperiod is a key environmental indicator for re gulating embryonic development,individual growth and physiological processes in aquatic animals.In this study,differences in embryonic development and performance of newly hatched cuttlefish juvenile exposed to five different cycles of light:dark(L:D):constant light,18 L:6D,12 L:12D,6 L:18D cycles,and constant darkness were evaluated.Prolonged exposure to light induced an accelerated rate of embryonic development,particularly after the red-bead stage.Principal component analysis(PCA)revealed that red-bead stage,heartbeat,endoskeleton formation,pigment appear,and six increments of cuttlebone were the main factors contributing to the embryonic development.Meaning that the duration time of these five stages were significantly different when exposed to photoperiod regimes,which may determine the duration of the incubation period of the embryos.Long term light has also affected the incubation parameters with an increased rate in hatching and shortened the incubation and hatching periods in the 12-24-h day length range.However,constant light and darkness environment appeared to have a greater effect on the stress of embryonic development,mainly reflected in the yolk shed ratio and the inking rate in the egg capsule.Moreover,the increase in the day length has contributed to improve the growth and survival of juveniles in the 12-18-h day length range;however,juveniles exposed to constant light and darkness experienced worse re sults in terms of growth,tissue glycogen content,dige stive enzymes of the digestive glands,and metabolic enzymes of the muscles.These finding suggest that prolonged light exposure accelerates the process of embryonic development,maximum feeding time is not necessarily a condition of optimal growth,and inappropriate light cycles can disturb the body’s endogenous controls.Therefore,the optimal photoperiod for the embryos development and juvenile growth of Sepia pharaonis were 12 h and 12-18 h of day length,respectively.These results are useful for increasing the production of this species during embryo incubation and juveniles rearing in aquaculture practice.

Clinical Epidemiology,Illness Profiles,and the Implication of COVID-19 Before and After the Nationwide Omicron Outbreak During the Winter of 2022

China.In this study,we aimed to investigate the clinical characteristics and outcomes of patients with coronavirus disease 2019(COVID-19)in the Beijing region.Methods:In this retrospective study,we enrolled inpatients admitted for COVID-19 in the Fifth Medical Center of Chinese PLA General Hospital in Beijing between November 10,2022,and January 30,2023.Demographic and clinical features and treatment outcomeswere comprehensively analyzed.We used logistic regression and linear regression analyses to explore the risk factors associated with disease severity and time of nucleic acid conversion,respectively.Results:A total of 1010 hospitalized patients with COVID-19 were enrolled.The median age was 43.0 years(interquartile range,28.0–63.0),and patients aged<60 years and≥60 years comprised 71.2%and 28.8%of total included patients,respectively.The clinical classification of mild(74.6%,753/1010),moderate(21.0%,212/1010),severe(2.7%,27/1010),and unidentified(1.8%,18/1010)was separately recorded;1005 patients were discharged,and 5 patients died in the hospital.The outbreak of the emerging epidemic witnessed an evident increase in the proportion of moderate(42.9%vs.16.4%)and severe(10.3%vs.1.1%)cases after December 7,2022.Patients with a moderate/severe classification had higher levels of procalcitonin,IL-6,serum ferritin,C-reactive protein,lactic dehydrogenase,serum urea nitrogen,and D-dimer and lower counts of CD4+T,CD8+T,and B cells(all P<0.001).Multivariable regression analysis revealed that increased odds of disease severity were associated with the following factors:age≥60 years,IL-6>7 pg/mL,lactic dehydrogenase level>245 U/L,cough,and fever at admission.Age≥80 years and chronic lung diseasewere independent risk factors in the nonmild group in elderly patients.In addition,the duration for nucleic acid to turn negativewas approximately 5.0 d(interquartile range,3.0–7.0).Prolonged time of nucleic acid conversion was associated with age≥60 years,serum urea nitrogen level>8.2 mmol/L,neutrophil count>7×10^(9)/L,and the presence of a chronic lung disease or carcinoma.Finally,unvaccinated patients accounted for 37.3%of enrolled patients;children and the elder people accounted for approximately half of that.The univariable analysis found that booster doses reduced disease severity and shortened the time of nucleic acid conversion in elderly patients.Conclusions:The outbreak ofOmicron rapidly increased the number of patientswith COVID-19 in Beijing.In elderly patients,booster doses may reduce disease severity and shorten the time of nucleic acid conversion.Healthcare systems should be optimized before an emerging epidemic outbreak.