Biology subjects

Bugg, W. S.

Publications and source records attributed to Bugg, W. S..

4 recordsLinked to original sources

bioRxiv2023

Integrated organismal responses induced by ecologically-relevant pCO2 and temperature exposures in developing lake sturgeon

Atmospheric CO2 and temperature are rising concurrently, and may have profound impacts on the transcriptional, physiological, and behavioral responses of aquatic organisms. Further, spring snow melt may cause transient increases of pCO2 in freshwater systems. Lake sturgeon (Acipenser fulvescens) groups were raised in current and projected levels of warming and pCO2. Following an overwintering period, lake sturgeon were exposed to a transient increase in pCO2, simulating a spring melt. Diverging transcriptional patterns were found in each group and metabolic rate was lower in the combined stressor group compared to others. Behavioral assays revealed no effect of environment on alarm cue responses or boldness, but there was a decrease in total activity following an acute CO2 exposure. These results demonstrate compensatory and compounding mechanisms of pCO2 and warming dependent on developmental conditions of a freshwater fish, and provide key information for responses to future climate change.

zoology↗

bioRxiv2023

Tenacibaculosis in wild-caught, captive Chinook salmon (Oncorhynchus tshawytscha) in British Columbia, Canada

Substantial, acute mortality was observed in wild-caught Chinook salmon (Oncorhynchus tshawytscha) of various ages and sizes, from sub-adults to returning adults, held in tanks during two holding studies carried out in August and September 2022 at the Bamfield Marine Sciences Centre (BMSC), in Bamfield, British Columbia, Canada. Within days of capture, a substantial number of fish began presenting lethargy, loss of balance, abnormal swimming behavior, and skin ulcers involving the caudal peduncle, fins, belly, trunk and mouth. Molecular testing revealed high levels of Tenacibaculum dicentrarchi in skin swabs and gills, without appreciable consistent detections of other infectious agents. T. dicentrarchi was also isolated from the skin ulcers. Histological analysis confirmed the presence of ulcerative dermatitis and myositis, associated with mats of filamentous, rod-shaped bacteria. In two individuals, the infection became systemic, with a bacterial colony (identified as T. dicentrarchi) observed in the liver of one individual. In-situ hybridization against T. dicentrarchi and T. maritimum confirmed the presence of only the former agent in the gills and skin ulcers of the affected fish. This clinical report represents the first diagnosed case of tenacibaculosis in wild-caught (captive) Chinook salmon in British Columbia. CONFLICT OF INTERESTThe authors have no conflicts of interest to report. DATA AVAILABILITY STATEMENTThe data that support the findings of this study are available from the corresponding author upon reasonable request.

pathology↗

bioRxiv2022

Tissue-specific transcriptomes reveal mechanisms of microbiome regulation in an ancient fish

The lake sturgeon (Acipenser fulvescens) is an ancient, octoploid fish faced with conservation challenges across its range in North America but a lack of genomic resources has hindered molecular research in the species. To support such research we aimed to provide a transcriptomic database from 13 tissues: brain, esophagus, gill, head kidney, heart, white muscle, liver, glandular stomach, muscular stomach, anterior intestine, pyloric cecum, spiral valve, and rectum. The transcriptomes for each tissue were sequenced and assembled individually from a mean of 98.3 million ({+/-}38.9 million std. dev.) reads each. In addition, an overall transcriptome was assembled and annotated with all data used for each tissue-specific transcriptome. All assembled transcriptomes and their annotations were made publicly available as a scientific resource. The non-gut transcriptomes provide important resources for many research avenues, however, the gut represents a compartmentalized organ system with compartmentalized functions and the sequenced gut tissues were from each of these portions. Therefore, we focused our analysis on mRNA transcribed in different tissues of the gut and explored evidence of microbiome regulation. Gene set enrichment analyses were used to reveal the presence of photoperiod and circadian-related transcripts in the pyloric caecum, which may support periodicity in lake sturgeon digestion. Similar analyses were used to identify different types of innate immune regulation across the gut, while analyses of unique transcripts annotated to microbes revealed heterogeneous genera and genes among different gut tissues. The present results provide a scientific resource and information about the mechanisms of compartmentalized function across gut tissues in a phylogenetically ancient vertebrate.

zoology↗

bioRxiv2022

Transcriptome-wide patterns reveal conserved and population-specific responses to increasing acclimation temperatures in developing lake sturgeon (Acipenser fulvescens)

Rising mean and variance in temperatures elevate threats to endangered freshwater species such as lake sturgeon, Acipenser fulvescens. Previous research demonstrated that higher temperatures during development result in physiological consequences for lake sturgeon populations throughout Manitoba, Canada, with alteration of metabolic rate, thermal tolerance, transcriptional responses, growth, and mortality. We acclimated lake sturgeon (30 - 60 days post fertilization, a period of high mortality) from northern and southern populations (56{degrees} 02' 46.5'' N, 96{degrees} 54' 18.6'' W and 50{degrees} 17' 52'' N, 95{degrees} 32' 51'' W respectively, separated by approximately 650 km) within Manitoba to current (summer highs of 20-23{degrees}C) and future projected (+2-3{degrees}C) environmental temperatures of 16, 20, and 24{degrees}C for 30 days, and measured gill transcriptional responses using RNAseq. Transcripts revealed SNPs consistent with genetically distinct populations and transcriptional responses altered by acclimation temperature. There were a higher number of differentially expressed transcripts observed in the southern, compared to the northern, population as temperatures increased, indicating enhanced transcriptional plasticity. Both lake sturgeon populations responded to elevated acclimation temperatures by downregulating the transcription of genes involved in protein synthesis and energy production. Further, there were population-specific thresholds for the downregulation of processes promoting transcriptional plasticity as well as mitochondrial function as the northern population showed decreases at 20{degrees}C, while this capacity was not diminished until 24{degrees}C in the southern population. These transcriptional responses highlight the molecular impacts of increasing temperatures for divergent lake sturgeon populations during vulnerable developmental periods and the critical influence of transcriptome plasticity on acclimation capacity.

molecular biology↗