Summer Mortality Syndrome Affecting Cultured European Seabass at Kafrelsheikh Province, Egypt

The present work aimed to investigate the causes of summer mortality syndrome affecting cultured European seabass (Dicentrarchus labrax) by examining physiochemical farm water characteristics, isolation, and identification of recovered bacterial pathogens from diseased fish studying the effect of water temperature on stress biomarkers and disease severity. Studied water parameters were normal except ammonia and dissolved oxygen was higher and lower than the standard value. Sixty-two bacterial isolates were recovered from moribund fish and identified as 31 Vibrio fluvialis, 23 Pseudomonas aeruginosa and 8 Staphylococcus aureus isolates. The calculated LD50 of V. fluvialis, P. aeruginosa and S. aureus for D. labrax fingerlings were 4.67 × 107, 2.37 × 106 and 1.38 × 107, respectively. There was a direct correlation between water temperature and mortality rate of fish challenged with V. fluvialis as the mortality rate was 44.44, 50, 66.66, and 83.33% for fish maintained at 27, 30, 33, and 36°C. Plasma cortisol, superoxide dismutase, catalase and malondialdehyde significantly increased when the water temperature exceeded 30°C. The experimentally infected fish showed similar clinical signs and postmortem lesions of naturally diseased fish with no boundary between different pathogens. Antibiogram test indicated that florfenicol was the most effective antibiotic against all the recovered bacterial isolates while all isolates resisted sulfamethoxazole-trimethoprim. Massive degenerative changes observed in the hepatopancreas, posterior kidney and gill tissues of experimentally infected fish.

A Small Regulatory RNA Generated from the malK 5′ Untranslated Region Targets Gluconeogenesis in Vibrio Species

Juvenile pacific oysters have been subject in recent years to summer mortality episodes with deep economic consequences. The pathogen Vibrio tasmaniensis has been associated with such mortality events.

Cross-sectional study for the clinical application of extracorporeal membrane oxygenation in Mainland China, 2018

Background To investigate the epidemiology and in-hospital mortality of veno-venous (VV) and veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) in Mainland China throughout 2018. Methods Patients supported by ECMO from 1700 tertiary hospitals in 31 provinces from January 1 to December 31, 2018, were selected from the National Clinical Improvement System database. Results The 1700 included hospitals had 2073 cases of ECMO in 2018, including 714 VV and 1359 VA ECMOs. The average patient age was 50 years (IQR 31–63), and 1346 were male. The average hospital stay was 17 days (IQR 7–30), and the average costs per case was $36,334 (IQR 22,547–56,714). The three provinces with the highest number of ECMO cases were Guangdong, Beijing, and Zhejiang; the southeast coastal areas and regions with higher GDP levels had more cases. Overall in-hospital mortality was 29.6%. Mortality was higher among patients who were male, over 70 years old, living in underdeveloped areas, and who were treated during the summer. Mortality in provinces with more ECMO cases was relatively low. The co-existence of congenital malformations, blood system abnormalities, or nervous system abnormalities increased in-hospital mortality. Conclusions Mortality and medical expenses of ECMO among patients in China were relatively low, but large regional and seasonal differences were present. Risk factors for higher in-hospital mortality were older age, male sex, in underdeveloped areas, and treatment during the summer. Additionally, congenital malformations and blood system and nervous system abnormalities were associated with in-hospital mortality.

Transcriptomic Analysis of the Reproductive Effects on Immunity in the Clam Meretrix Petechialis During the Breeding Season

Background: Immune defense and reproduction are both physiologically demanding processes, therefore the trade-off is expected between them in breeding season. Although this balance strategy has been extensively studied in many species, it is still rarely noticed in mollusc. Moreover, summer mortality of marine bivalve often occurs during breeding season and reproduction is suspected to play a significant role for the mass death. Results: To address if spawning affects immunity to cause clam death, we performed transcriptome and gene expression analyses in the clam Meretrix petechialis pre-/post-spawning. DEGs enrichment analysis revealed important immune signaling pathways and key genes changed after spawning. Further analysis showed females up-regulated genes involved in apoptosis, TLR signal pathway and heat shock, whereas males down-regulated complement-related genes after spawning. Additionally, both genders of clams up-regulated its immune response level to against Vibrio infection after spawning revealed by the changes of four immune-related DEGs. Conclusions: The spawning indeed affected the clam immune resistance. The immune and defense related genes and pathways obtained here provide important insights into the molecular mechanisms of physiological acclimation and immune response under reproduction-influence and offers some clues to explain the possible reason for clam summer mortality.

Several complementary methods of plant establishment are required for effective restoration of banksia woodland

New banksia woodland vegetation was established at two sites totalling 50 ha in the Perth region of Western Australia as part of an offset-funded project. Restoration methods included topsoil transfer (16 ha), planting of nursery-raised local provenance seedlings (46,000 seedlings over 39.5 ha) and direct seeding with machinery or by hand (16.5 ha) with treatments overlapped. Six years of rigorous monitoring revealed trends in plant diversity, density and cover and allowed comparison of vegetation structure and composition to reference sites. Of the 162 native plants recorded, 115 originated primarily from the topsoil seed bank and the remainder from planting and seeding. Native plant germination from topsoil peaked at 700,000 stems per ha in year 2, but there was very high attrition during extreme summer drought. By year 5, native perennials averaged 20,000 stems per ha, well above the target of 7,000, but there was high spatial variability in plant density with 1/3 of quadrats below target. Saplings of Banksia spp. (the dominant local trees) plateaued at 150-220 stems per ha due to high summer mortality. Native plant cover reached 20% and perennial weed cover stabilised at under 5% within 5 years. Several complimentary methods were required for successful restoration, since transferred topsoil established most of the plant diversity. However, trees required planting or seeding, due to their canopy stored seed. Direct seeding and planting without respread topsoil led to lower overall diversity and density, but higher tree density. Most completion criteria targets were reached after 5 years. Areas with respread topsoil are trending towards recovery as a banksia woodland, but areas with only planting and seeding are likely to remain a separate vegetation type. Evidence for resilience of restored areas was provided by abundant pollination and seed set and second-generation seedlings. We suggest it may be possible to restore banksia woodland despite major challenges due to unpredictable offset funding, climate, weeds, grazing, recalcitrant species, and seed availability, but long-term monitoring is required to confirm this.