UMBC Department of Marine Biotechnology
Permanent URI for this collectionhttp://hdl.handle.net/11603/12175
The Department of Marine Biotechnology (DMB) is partner member of the Institute of Marine and Environmental Technology (IMET), a joint University System of Maryland research institute capitalizing on the strengths of the University of Maryland, Baltimore County, the University of Maryland Center for Environmental Sciences, and the University of Maryland, Baltimore. DMB is premier research center for basic and translational research in marine biotechnology and molecular microbiology. Researchers use the tools of modern molecular biology and biotechnology to make basic scientific discoveries that may be applied to study, protect and enhance marine and estuarine resources. DMB faculty focus on key areas of marine molecular biology to solve practical problems confronting the Chesapeake Bay and the greater marine ecosystem and to develop new technologies for translational application and economic advancement. DMB provides an exceptional environment for specialized training and mentoring of tomorrow’s biotechnology workforce.
The department is based at the Columbus Center in downtown Baltimore. Faculty have access to extensive research facilities, including an 18,000 square-foot, fully-contained, recirculating marine aquaculture facility, a versatile high-volume fermentation facility, and a wide assortment of advanced biomolecular instrumentation.
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Item GnRH—Gonadotropes Interactions Revealed by Pituitary Single-cell Transcriptomics in Zebrafish(Oxford University Press, 2024-11-06) Tanaka, Sakura; Yu, Yang; Levavi-Sivan, Berta; Zmora, Nilli; Zohar, YonathanGonadotropin-releasing hormone (GnRH) governs reproduction by regulating pituitary gonadotropins. Unlike most vertebrates, gnrh⁻/⁻ zebrafish are fertile. To elucidate the role of the hypophysiotropic-Gnrh3 and other mechanisms regulating pituitary gonadotropes, we profiled the gene expression of all individual pituitary cells of wild-type and gnrh3⁻/⁻ adult female zebrafish. The single-cell RNA-Seq showed that Lh and Fsh gonadotropes express the two gonadotropin beta subunits with a ratio of 140:1 (lhb:fshb) and 4:1 (fshb:lhb), respectively. Lh gonadotropes predominantly express genes encoding receptors for Gnrh (gnrhr2), thyroid hormone, estrogen, and steroidogenic factor 1 (SF1). No Gnrh receptor transcript was enriched in Fsh gonadotropes. Instead, cholecystokinin receptor-b and galanin receptor-1b transcripts were enriched in these cells. The loss of Gnrh3 gene in gnrh3⁻/⁻ zebrafish resulted in downregulation of fshb in Lh gonadotropes and upregulation of pituitary hormones like thyroid-stimulating hormone, growth hormone, prolactin and proopiomelanocortin-a. Likewise, targeted chemogenetic ablation of Gnrh3 neurons led to a decrease in the number of fshb+, lhb+ and fshb+/lhb+ cells. Our studies suggest that Gnrh3 directly acts on Lh gonadotropes through Gnrhr2, but the outcome of this interaction is still unknown. Gnrh3 also regulates fshb expression in both gonadotropes, most likely via a non-Gnrh receptor route. Altogether, while Lh secretion and synthesis are likely regulated in a Gnrh-independent manner, Gnrh3 seems to play a role in the cellular organization of the pituitary. Moreover, the co-expression of lhb and fshb in both gonadotropes provides a possible explanation as to why gnrh3⁻/⁻ zebrafish are fertile.Item Newcastle Disease Virus Expressing Cap Gene of Porcine Circovirus Type 2 Confers Protection in Mice and Induced Long-Lasting Neutralizing Antibodies in Pigs(MDPI, 2024-11-15) Dey, Sohini; Murugasamy, Rudhreswaran; Buragohain, Lukumoni; D’silva, Ajai Lawrence; Sarma, Jayashree; Bharali, Arpita; Ramakrishnan, Saravanan; Saminathan, Mani; Barman, Nagendra Nath; Vakharia, Vikram; Chellappa, Madhan MohanBackground/Objectives: Porcine Circovirus 2 (PCV2) infection poses significant health and economic challenges to the global swine industry. The disease in pigs leads to lymphoid depletion, resulting in immunosuppression and increased susceptibility to co-infections with other bacterial and viral pathogens. This study evaluated the efficacy of two novel recombinant Newcastle disease virus (NDV) strain R2B vectored vaccines that express the cap gene of PCV2 alone and along with the transmembrane and cytoplasmic tail (TMCT) domains of the NDV F gene. The efficacy of the vaccine candidates was studied in mouse and pig models. Methods: Six-week-old BALB/c mice were divided into five groups and immunized intramuscularly three times at 14-day intervals with various vaccine candidates, namely rNDV-R2B-PCVcap-TMCT, rNDV-R2B-PCVcap, and CircoFLEX commercial vaccine, along with controls. Following immunization and PCV2d virus challenge, multiple assays assessed the immune responses in animal trials. In the pig animal trial, pigs were divided into four groups: a control group (PBS), NDV-vectored PCVcap-TMCT group, NDV-vectored-PCVcap group, and CircoFLEX vaccine group. Pigs were immunized intramuscularly twice at 28-day intervals. Blood samples were collected at regular intervals over 70 days to evaluate the humoral and cell-mediated immune responses. Results: Both mice and pigs’ trials indicated that the NDV-vectored PCV2 cap-TMCT vaccine candidate elicited superior immune responses. In mice, the rNDV-R2B-PCVcap-TMCT group showed enhanced humoral and cellular immunity, increased PCV2-specific antibody levels, higher CD4+/CD8+ ratio, elevated IFN-γ and TNF-α levels, decreased IL-10 levels, reduced viral loads, and minimal histopathological changes. In pigs, the NDV-vectored PCVcap-TMCT group demonstrated better antibody responses, cytokine profiles (IFN-γ and IL-10), and higher levels of PCV2-specific neutralizing antibodies against the PCV2a, PCV2b and PCV2d genotypes when compared to other groups. Conclusions: These findings suggest NDV-vectored PCVcap-TMCT vaccine candidate, expressing the cap gene of PCV2 along with the TMCT domain, offers a promising alternative for protecting against PCV2 infection, potentially addressing the challenges posed by emerging PCV2 strains in the swine industry.Item Phytoplankton uptake by a resilient urban estuary bivalve, Mytilopsis leucophaeata(2024-09-02) Kido, Allyson; Mansfield, Noah; Schott, EricUrban estuaries face numerous problems stemming from excess nutrients from stormwater runoff. Baltimore Harbor, an urban estuary, has intense and frequent phytoplankton blooms that can lead to hypoxic and anoxic zones, and ultimately fish kills. Efforts to reduce the nutrients, that fuel algae blooms, focus on point sources and not remediation once the nutrients have entered the water. In water removal of nutrients is often in the form of phytoplankton uptake by bivalve suspension feeders. Commercial bivalve species have been studied for their ability to remove phytoplankton and sequester nutrients in the coastal zone. In urban estuaries, commercially important bivalves often do not naturally occur, or urban pollution would make them unsuitable for human consumption. Therefore, we set out to determine if a locally abundant non-commercial mussel, Mytilopsis leucophaeata , could reduce phytoplankton levels and how environmentally relevant temperature and salinity may impact clearance rates. Our study developed a standard method to quantify phytoplankton removal of two cultured phytoplankton species ( Isochrysis sp. and Chaetoceros sp. ), by measuring both in vivo and extracted chlorophyll. We then evaluated the ability of the mussels to remove algae under varied temperatures and salinity that are typical for Baltimore Harbor. Our results show that at lower temperatures there is a lower clearance rate, and salinity did not significantly affect the clearance rates of the mussels. Overall, our results show potential for the use of this native non-commercial bivalve to reduce phytoplankton blooms in Baltimore Harbor.Item In Situ Enzymatic Conversion of Nannochloropsis oceanica IMET1 Biomass into Fatty Acid Methyl Esters(Springer, 2017-06-01) Wang, Yao; Lee, Yi-Ying; Santaus, Tonya; Newcomb, Charles E.; Liu, Jin; Geddes, Chris; Zhang, Chengwu; Hu, Qiang; Li, YantaoConventionally, production of methyl ester fuels from microalgae occurs through an energy-intensive two-step chemical extraction and transesterification process. To improve the energy efficiency, we performed in situ enzymatic conversion of whole algae biomass from an oleaginous heterokont microalga Nannochloropsis oceanica IMET1 with the immobilized lipase from Candida antarctica. The fatty acid methyl ester yield reached 107.7% for dry Nannochloropsis biomass at biomass to t-butanol to methanol weight ratio of 1:2:0.5 and a reaction time of 12 h at 25 °C, representing the first report of efficient whole algae biomass conversion into fatty acid methyl esters at room temperature. Different forms of algal biomass including wet Nannochloropsis biomass were tested. The maximum yield of wet biomass was 81.5%. Enzyme activity remained higher than 95% after 55 days of treatment (equal to 110 cycles of reaction) under the conditions optimized for dry algae biomass conversion. The low reaction temperature, high enzyme stability, and high yield from this study indicate in situ enzymatic conversion of dry algae biomass may potentially be used as an energy-efficient method for algal methyl ester fuel production while allowing co-product recovery.Item High infectivity and waterborne transmission of seagrass wasting disease(The Royal Society, 2024-08-07) Eisenlord, Morgan E.; Agnew, M. Victoria; Winningham, Miranda; Lobo, Olivia J.; Vompe, Alex D.; Wippel, Bryanda; Friedman, Carolyn S.; Harvell, C. Drew; Burge, ColleenPathogen transmission pathways are fundamental to understanding the epidemiology of infectious diseases yet are challenging to estimate in nature, particularly in the ocean. Seagrass wasting disease (SWD), caused by Labyrinthula zosterae, impacts seagrass beds worldwide and is thought to be a contributing factor to declines; however, little is known about natural transmission of SWD. In this study, we used field and laboratory experiments to test SWD transmission pathways and temperature sensitivity. To test transmission modes in nature, we conducted three field experiments out-planting sentinel Zostera marina shoots within and adjacent to natural Z. marina beds (20 ± 5 and 110 ± 5 m from bed edge). Infection rates and severity did not differ among outplant locations, implicating waterborne transmission. The infectious dose of L. zosterae through waterborne exposure was assessed in a controlled laboratory experiment. The dose to 50% disease was 6 cells ml⁻¹ and did not differ with the temperatures tested (7.5°C and 15°C). Our results show L. zosterae is transmissible through water without direct contact with infected plants. Understanding the transmission dynamics of this disease in the context of changing ocean conditions will improve Z. marina protection and restoration in critical coastal habitats worldwide.Item Loss of function of Vasoactive-intestinal peptide alters sex ratio and reduces male reproductive fitness in zebrafish(Oxford University Press, 2024-07-10) Yu, Yang; Tanaka, Sakura; Wong, Ten-Tsao; Zohar, Yonathan; Zmora, NilliVasoactive-intestinal peptide (Vip) is a pleiotropic peptide with a wide range of distribution and functions. Zebrafish possess two isoforms of Vip (a and b), in which Vipa is most homologous to the mammalian form. In female zebrafish, Vipa can stimulate LH secretion from the pituitary but is not essential for female reproduction, as vipa-/- females display normal reproduction. In contrast, we have found that vipa-/- males are severely sub-fertile and sex ratio of offspring is female-biased. By analyzing all aspects of male reproduction with WT males, we show that the testes of vipa-/- are underdeveloped and contain ∼70% less spermatids compared to WT counterparts. The sperm of vipa-/- males displayed reduced potency in terms of fertilization (by ∼80%) and motility span and duration (by ∼50%). In addition, vipa-/- male attraction to WT females was largely non-existent, indicating decreased sexual motivation. We show that vipa mRNA and protein is present in Leydig cells and in developing germ cells in the testis of WT, raising the possibility that endogenous Vipa contributes to testicular function. Absence of Vipa in vipa-/- males resulted in downregulation of three key genes in the androgen synthesis chain in the testis, 3β-hsd, 17β-hsd1 and cyp11c1 (11β-hydrogenase), associated with a pronounced decrease in 11-ketotestosterone production and, in turn, compromised reproductive fitness. Altogether, this study establishes a crucial role for Vipa in the regulation of male reproduction in zebrafish, like in mammals, with the exception that Vipa is also expressed in zebrafish testis.Item Reefs in no-take reserves host more oysters, macroparasites, and macrofauna than harvested reefs across an estuarine salinity gradient(Inter-Research, 2024-07-04) Anchondo, Zofia B.; Tracy, Allison M.; Raza, Aiman; Meckler, Karli A.; Ogburn, Matthew B.No-take reserves and habitat restoration are important management tools for reversing the effects of fishing on coastal habitats, associated faunal assemblages, and host–parasite interactions. Populations of the eastern oyster Crassostrea virginica have declined by 99 % in areas of Chesapeake Bay, USA, due to overharvesting, disease, and other factors, and are now the focus of extensive restoration efforts. We surveyed subtidal oyster reefs using classic quantitative approaches and emerging videography methods to contrast pairs of harvested reefs and reefs protected in subtidal no-take marine reserves (oyster sanctuaries) in the Choptank, Great Wicomico, and James River tributaries of Chesapeake Bay. Overall, sanctuary oyster reefs contained more intact habitats and communities. Relative to nearby harvested reefs, sanctuary reefs (1) contained higher densities of oysters, (2) held larger oysters of lower condition, (3) hosted stronger oyster–macroparasite (boring sponge [Cliona spp.] and mud blister worm [Polydora spp.]) interactions, (4) had more complex habitat, and (5) supported a greater richness and abundance of macrofauna. Oyster and mobile macrofauna abundance increased with salinity, whereas macroparasite prevalence peaked at mesohaline (5–20 psu) sites. Our results suggest that restored, sanctuaryprotected oyster reefs are beginning to rebound from the effects of >100 yr of intensive harvest, as indicated by increased oyster density, recovery of host–parasite interactions, improved habitat characteristics, and more mobile macrofauna. Additionally, these patterns, observed across the salinity gradient in Chesapeake Bay, reflect a widespread trend in aquatic ecology: relative to fished areas, unfished areas have more complex habitats and communities, larger and higher densities of hosts, and stronger host–parasite interactions.Item Heterologous Exchanges of Glycoprotein and Non-Virion Protein in Novirhabdoviruses: Assessment of Virulence in Yellow Perch (Perca flavescens) and Rainbow Trout (Oncorhynchus mykiss)(MDPI, 2024-04-22) Vakharia, Vikram; Ammayappan, Arun; Yusuff, Shamila; Tesfaye, Tarin M.; Kurath, GaelInfectious hematopoietic necrosis virus (IHNV) and viral hemorrhagic septicemia virus (VHSV) are rhabdoviruses in two different species belonging to the Novirhabdovirus genus. IHNV has a narrow host range restricted to trout and salmon species, and viruses in the M genogroup of IHNV have high virulence in rainbow trout (Oncorhynchus mykiss). In contrast, the VHSV genotype IVb that invaded the Great Lakes in the United States has a broad host range, with high virulence in yellow perch (Perca flavescens), but not in rainbow trout. By using reverse-genetic systems of IHNV-M and VHSV-IVb strains, we generated six IHNV:VHSV chimeric viruses in which the glycoprotein (G), non-virion-protein (NV), or both G and NV genes of IHNV-M were replaced with the analogous genes from VHSV-IVb, and vice versa. These chimeric viruses were used to challenge groups of rainbow trout and yellow perch. The parental recombinants rIHNV-M and rVHSV-IVb were highly virulent in rainbow trout and yellow perch, respectively. Parental rIHNV-M was avirulent in yellow perch, and chimeric rIHNV carrying G, NV, or G and NV genes from VHSV-IVb remained low in virulence in yellow perch. Similarly, the parental rVHSV-IVb exhibited low virulence in rainbow trout, and chimeric rVHSV with substituted G, NV, or G and NV genes from IHNV-M remained avirulent in rainbow trout. Thus, the G and NV genes of either virus were not sufficient to confer high host-specific virulence when exchanged into a heterologous species genome. Some exchanges of G and/or NV genes caused a loss of host-specific virulence, providing insights into possible roles in viral virulence or fitness, and interactions between viral proteins.Item Ecological Factors Mediate Immunity and Parasitic Co-Infection in Sea Fan Octocorals(Frontiers, 2021-01-10) Tracy, Allison M.; Weil, Ernesto; Burge, ColleenThe interplay among environment, demography, and host-parasite interactions is a challenging frontier. In the ocean, fundamental changes are occurring due to anthropogenic pressures, including increased disease outbreaks on coral reefs. These outbreaks include multiple parasites, calling into question how host immunity functions in this complex milieu. Our work investigates the interplay of factors influencing co-infection in the Caribbean sea fan octocoral, Gorgonia ventalina, using metrics of the innate immune response: cellular immunity and expression of candidate immune genes. We used existing copepod infections and live pathogen inoculation with the Aspergillus sydowii fungus, detecting increased expression of the immune recognition gene Tachylectin 5A (T5A) in response to both parasites. Cellular immunity increased by 8.16% in copepod infections compared to controls and single Aspergillus infections. We also detected activation of cellular immunity in reef populations, with a 13.6% increase during copepod infections. Cellular immunity was similar in the field and in the lab, increasing with copepod infections and not the fungus. Amoebocyte density and the expression of T5A and a matrix metalloproteinase (MMP) gene were also positively correlated across all treatments and colonies, irrespective of parasitic infection. We then assessed the scaling of immune metrics to population-level disease patterns and found random co-occurrence of copepods and fungus across 15 reefs in Puerto Rico. The results suggest immune activation by parasites may not alter parasite co-occurrence if factors other than immunity prevail in structuring parasite infection. We assessed non-immune factors in the field and found that sea fan colony size predicted infection by the copepod parasite. Moreover, the effect of infection on immunity was small relative to that of site differences and live coral cover, and similar to the effect of reproductive status. While additional immune data would shed light on the extent of this pattern, ecological factors may play a larger role than immunity in controlling parasite patterns in the wild. Parsing the effects of immunity and ecological factors in octocoral co-infection shows how disease depends on more than one host and one parasite and explores the application of co-infection research to a colonial marine organism.Item Microalgal and bacterial auxin biosynthesis: implications for algal biotechnology(Elsevier, 2021-10-04) Lin, Hanzhi; Li, Yantao; Hill, Russell T.Optimization of microalgal growth and high-value metabolite production are key steps in microalgal mass culture for the algae industry. An emerging technology is the use of phytohormones, like indole-3-acetic acid (IAA), to promote microalgal growth. This requires an understanding of the biosynthesis of IAA in microalgae-bacteria associations and its function in regulating algal physiology and metabolite production. We review the current advances in understanding of microalgal and bacterial auxin biosynthesis and their implications for algal biotechnology.Item PDAT regulates PE as transient carbon sink alternative to triacylglycerol in Nannochloropsis(Oxford University Press, 2022-04-06) Yang, Juan; Liu, Jin; Pan, Yufang; Maréchal, Eric; Amato, Alberto; Liu, Meijing; Gong, Yangmin; Li, Yantao; Hu, HanhuaTriacylglycerols (TAGs) are the main storage lipids in photosynthetic organisms under stress. In the oleaginous alga Nannochloropsis oceanica, while multiple acyl CoA:diacylglycerol (DAG) acyltransferases (NoDGATs) are involved in TAG production, the role of the unique phospholipid:DAG acyltransferase (NoPDAT) remains unknown. Here, we performed a functional complementation assay in TAG-deficient yeast (Saccharomyces cerevisiae) and an in vitro assay to probe the acyltransferase activity of NoPDAT. Subcellular localization, overexpression, and knockdown (KD) experiments were also conducted to elucidate the role of NoPDAT in N. oceanica. NoPDAT, residing at the outermost plastid membrane, does not phylogenetically fall into the clades of algae or plants and uses phosphatidylethanolamine (PE) and phosphatidylglycerol with 16:0, 16:1, and 18:1 at position sn-2 as acyl-donors in vivo. NoPDAT KD, not triggering any compensatory mechanism via DGATs, led to an ~30% decrease of TAG content, accompanied by a vast accumulation of PEs rich in 16:0, 16:1, and 18:1 fatty acids (referred to as “LU-PE”) that was positively associated with CO₂ availability. We conclude that the NoPDAT pathway is parallel to and independent of the NoDGAT pathway for oil production. LU-PE can serve as an alternative carbon sink for photosynthetically assimilated carbon in N. oceanica when PDAT-mediated TAG biosynthesis is compromised or under stress in the presence of high CO₂ levels.Item Engineering whiting events in culture: A microalgae-driven calcium carbonate and biomass production process at high pH and alkalinity with the marine microalga Nannochloropsis oceanica IMET1(Elsevier, 2024-01-18) Lee, Yi-Ying; Jonas, Lauren; Hill, Russell; Place, Allen; Silsbe, Greg; Hunsicker, Scott; North, Elizabeth; Li, YantaoThe impact of whiting events on global inorganic carbon cycle and climate change is debatable at the current ocean pH. This work engineered whiting events in a high pH, high alkalinity microalgal culture for carbon dioxide capture and storage. When growing the marine microalga Nannochloropsis oceanica IMET1 in photobioreactors, culture alkalinity more than doubled, increasing from 72.5 mg L⁻¹ to a maximum level of 159.6 mg L⁻¹. At the same time, culture pH increased from 7.9 to 10.1 with concomitant calcium carbonate production. X-ray diffraction analysis revealed the precipitated calcium carbonate was primarily monohydrocalcite. The lab culture was scaled up to a 340-L bioreactor, in which Nannochloropsis ash-free dry weight productivities ranged from 25.1 to 51.4 g m⁻² d⁻¹ and a maximum monohydrocalcite productivity of 133.4 g m² d⁻¹ was recorded. In this system, Nannochloropsis biomass contained about 23.9 % lipids and the eicosapentaenoic acid content was about 1.8 %. Together, these results suggest the microalgae-driven calcium carbonate and biomass production process efficiently captures and stores atmospheric carbon dioxide in the form of calcium carbonate while producing valuable bioproducts. Study of the bacterial communities associated with the Nannochloropsis culture identified four dominant species Maricaulis maris, Marinisubtilis pacificus, Gracilimonas sp., and an uncultured bacterium in the OD1 phylum with interesting features that warrant further investigation.Item Identifying the genes involved in the egg-carrying ovigerous hair development of the female blue crab Callinectes sapidus: transcriptomic and genomic expression analyses(BMC Genomics, 2023-12-11) Wang, Tao; Bachvaroff, Tsvetan; Chung, J. SookBackground Crustacean female sex hormone (CFSH) controls gradually developing adult female-specific morphological features essential for mating and brood care. Specifically, ovigerous hairs are developed during the prepuberty molt cycle of the blue crab Callinectes sapidus that are essential for carrying the eggs until they finish development. Reduced CFSH transcripts by CFSH-dsRNA injections result in fewer and shorter ovigerous hairs than the control. This study aimed to identify the specific genes responsible for ovigerous hair formation using transcriptomic, genomic and expression analyses of the ovigerous setae at three stages: prepuberty at early (OE) and late premolt (OL), and adult (AO) stages. Results The de novo Trinity assembly on filtered sequence reads produced 96,684 Trinity genes and 124,128 transcripts with an N50 of 1,615 bp. About 27.3% of the assembled Trinity genes are annotated to the public protein sequence databases (i.e., NR, Swiss-Prot, COG, KEGG, and GO databases). The OE vs. OL, OL vs. AO, and OE vs. AO comparisons resulted in 6,547, 7,793, and 7,481 differentially expressed genes, respectively, at a log2-fold difference. Specifically, the genes involved in the Wnt signaling and cell cycle pathways are positively associated with ovigerous hair development. Moreover, the transcripts of ten cuticle protein genes containing chitin-binding domains are most significantly changed by transcriptomic analysis and RT-qPCR assays, which shows a molt-stage specific, down-up-down mode across the OE-OL-AO stages. Furthermore, the expression of the cuticle genes with the chitin-binding domain, Rebers and Riddiford domain (RR)-1 appears at early premolt, followed by RR-2 at late premolt stage. Mapping these 10 cuticle protein sequences to the C. sapidus genome reveals that two scaffolds with a 549.5Kb region and 35 with a 1.19 Mb region harbor 21 RR1 and 20 RR2 cuticle protein genes, respectively. With these findings, a putative mode of CFSH action in decapod crustaceans is proposed. Conclusions The present study describes a first step in understanding the mechanism underlying ovigerous hair formation in C. sapidus at the molecular level. Overall, demonstrating the first transcriptome analysis of crustacean ovigerous setae, our results may facilitate future studies into the decapod female reproduction belonging to the suborder Pleocyemata.Item Induction of Reproductive Sterility in Coho Salmon (Oncorhynchus kisutch) by an Immersion-Based Gene Silencing Technology(MDPI, 2023-11-21) Xu, Lan; Zhao, Mingli; Zohar, Yonathan; Wong, Ten-TsaoUndesired maturation and reproduction are major challenges in fish aquaculture regarding genetic introgression, precocious maturation, and reproduction-related mortality, which can have profound ecological or economic impacts. Farming reproductively sterile fish can effectively mitigate these challenges. In this paper, we transferred and applied a novel immersion-based, non-transgenic gene silencing technology to sterilize coho salmon for the first time. Unfertilized eggs were bath immersion-treated with csdnd-MO-Vivo in different immersion media. Eyed rates of treated groups ranged from 0.9 to 63.5%. Sterile fish lacking germ cells, and those with arrested germ cells/atretic oocytes, were obtained at 14 and 20 months of age, albeit at a low percentage (2.3 to 10.0% based on females). Gonadal histology and vasa/nanos3 gene expression profile were provided for comparing fertile and sterile gonads, as well as retarded ovaries. Future directions and strategies for optimizing the technology and improving sterility induction were also proposed. The successful production of sterile coho salmon achieved in this study demonstrates the proof of principle for this new sterilization technology. As we continue to expand upon these findings and refine the technology, achieving coho salmon sterile population farming would facilitate the future transfer and application to other commercially important aquaculture fish.Item Oyster reef habitat depends on environmental conditions and management across large spatial scales(Inter-Research Science Publisher, 2023-10-19) Tracy, Allison M.; Heggie, Keira; Ritter, Carmen; Norman, Dave; Aguilar, Rob; Ogburn, Matthew B.Oyster reefs provide important services to ecosystems and people, with many of these benefits depending on structurally complex reef habitat. Despite the key role of oyster reef habitat, we have yet to understand natural and anthropogenic drivers of subtidal reef habitat over large spatial scales (>200 km). Chesapeake Bay (USA) offers a valuable system to explore how salinity, restoration, and harvest compare in their influence on subtidal oyster reef habitat because of its broad environmental gradient and mosaic of management types. We applied a remote rapid assessment method using underwater photographs to survey oyster reef habitat in 12 tributaries and scored images based on estimates of oyster percent cover and vertical relief. The broad spatial scale (~215 km) of the survey includes reefs that vary in management status and salinity. Bay-wide habitat scores were higher with greater estimated oyster percent cover and vertical relief on unharvested and restored reefs. Salinity also contributed to Chesapeake Bay-wide patterns, but the relationship depended on harvest status. In assessing the separate management jurisdictions, scores were higher on restored reefs in Maryland and on anthropogenic (i.e. artificially supplemented) reefs in Virginia. A time series over 4 yr in 2 Maryland tributaries showed high and persistent habitat scores in restored sanctuaries, but habitat scores increased for all reefs over time. The results highlight the combined roles of the natural environment and management decisions on oyster reef habitat. The effect of harvest and restoration on habitat underscores the importance of local management decisions in determining the future status of oyster reefs.Item Cross-Hemispheric Genetic Diversity and Spatial Genetic Structure of Callinectes sapidus Reovirus 1 (CsRV1)(MDPI, 2023-02-18) Zhao, Mingli; Plough, Louis V.; Behringer, Donald C.; Bojko, Jamie; Kough, Andrew S.; Alper, Nathaniel W.; Xu, Lan; Schott, Eric J.The movement of viruses in aquatic systems is rarely studied over large geographic scales. Oceanic currents, host migration, latitude-based variation in climate, and resulting changes in host life history are all potential drivers of virus connectivity, adaptation, and genetic structure. To expand our understanding of the genetic diversity of Callinectes sapidus reovirus 1 (CsRV1) across a broad spatial and host life history range of its blue crab host (Callinectes sapidus), we obtained 22 complete and 96 partial genomic sequences for CsRV1 strains from the US Atlantic coast, Gulf of Mexico, Caribbean Sea, and the Atlantic coast of South America. Phylogenetic analyses of CsRV1 genomes revealed that virus genotypes were divided into four major genogroups consistent with their host geographic origins. However, some CsRV1 sequences from the US mid-Atlantic shared high genetic similarity with the Gulf of Mexico genotypes, suggesting potential human-mediated movement of CsRV1 between the US mid-Atlantic and Gulf coasts. This study advances our understanding of how climate, coastal geography, host life history, and human activity drive patterns of genetic structure and diversity of viruses in marine animals and contributes to the capacity to infer broadscale host population connectivity in marine ecosystems from virus population genetic data.Item "What is the Shape of Water" with CIRCA-IMET Artist-in-Residence(IMET, 2019-06-26) Agnew, ToriItem Pacific oysters are a sink and a potential source of the eelgrass pathogen, Labyrinthula zosterae(Inter-Research, 2022-12-15) Agnew, M Victoria; Groner, Maya L.; Eisenlord, Morgan E.; Friedman, Carolyn S.; Burge, ColleenOyster aquaculture and seagrasses often co-occur and are each vital to the ecological and economic value of coastal ecosystems. Global declines in seagrasses, including Zostera mari - na, have recently been observed in association with multiple factors, including infection with diseases such as seagrass wasting disease (SWD), caused by the protist Labyrinthula zosterae. Protection of seagrasses has led to restrictions on oyster aquaculture due to perceived negative impacts on seagrass beds; however, positive impacts may also occur. An important aquaculture species, the Pacific oyster Crassostrea gigas, can filter L. zosterae from the water, potentially re - ducing pathogen transmission, although oysters may vector infection if they accumulate and re - lease live L. zosterae into the water. We investigated whether oyster presence decreases lesion severity and infection intensity in eelgrass, or acts as a vector of L. zosterae, via laboratory and field experiments. In the laboratory, oysters and eelgrass were exposed to L. zosterae for 24 h and kept at 11°C or 18°C for 13 d. In the field, eelgrass ramets were deployed with and without oysters for 28 d adjacent to eelgrass known to have SWD. In the laboratory experiment, the presence of oysters significantly decreased lesion severity and infection intensity, but oysters previously ex - posed to L. zosterae did transmit the pathogen to naïve eelgrass. Temperature did not affect oyster ability to mitigate SWD; however, increased temperature significantly increased lesion severity. Oysters had no effect on SWD in the field. Further research is needed regarding the potential for oysters to vector L. zosterae and to quantify when oysters reduce SWD in the field.Item Seasonal trends of PCBs in air over Washington DC reveal localized urban sources and the influence of Anacostia River(Elsevier, 2022-10-27) Bokare, Mandar; Lombard, Nathalie; Magee, Samuel; Murali, Dev; Ghosh, UpalSemi-volatile organic compounds like polychlorinated biphenyls (PCBs) undergo diffusive exchange flux between a water body and the overlying air. The magnitude of this exchange can be a substantial component of the overall pollutant mass balance and needs to be determined accurately to identify major pollutant sources to the water body and to plan appropriate remedies. For the PCB-impacted Anacostia River in Washington DC (USA), quantification of air-water exchange has been a major data gap. In the present study, polyethylene passive samplers were used to measure PCB concentrations in air phase at six locations in DC over a period of one year to capture spatial and seasonal variations. Concurrent water phase PCB measurements were used to quantify the direction and magnitude of air-water exchange in the Anacostia River. Two locations had nearly an order of magnitude higher air phase PCB concentrations that could be related to localized sources. Remaining four locations provided similar air phase PCB concentrations that averaged from 270 ± 44 pg/m3 (summer) to 32 ± 4.3 pg/m3 (winter). ∑PCB water-air exchange fluxes were positive across all seasons, with net PCB volatilization of 180 ± 19 g/year from the surface water. Volatilization rate was an order of magnitude lower than previously estimated from a fate and transport model. PCB load from atmospheric deposition based on previous studies in this watershed was an order of magnitude lower than the volatilization rate. Results refuted a long-standing understanding of the air phase serving as a source of PCBs to the river as per the currently approved Total Maximum Daily Load assessment. The study demonstrates the utility of passive air phase measurements in delineating local terrestrial sources of pollution as well as providing estimates for air-water exchange to complete a robust mass balance for semi-volatile pollutants in an urban river.Item Genetic compensation of triacylglycerol biosynthesis in the green microalga Chlamydomonas reinhardtii(Wiley, 2022-06-21) Lee, Yi-Ying; Park, Rudolph; Miller, Stephen M.; Li, YantaoGenetic compensation has been proposed to explain phenotypic differences between gene knockouts and knockdowns in several metazoan and plant model systems. With the rapid development of reverse genetic tools such as CRISPR/Cas9 and RNAi in microalgae, it is increasingly important to assess whether genetic compensation affects the phenotype of engineered algal mutants. While exploring triacylglycerol (TAG) biosynthesis pathways in the model alga Chlamydomonas reinhardtii, it was discovered that knockout of certain genes catalyzing rate-limiting steps of TAG biosynthesis, type-2 diacylglycerol acyltransferase genes (DGTTs), triggered genetic compensation under abiotic stress conditions. Genetic compensation of a DGTT1 null mutation by a related PDAT gene was observed regardless of the strain background or mutagenesis approach, for example, CRISPR/Cas 9 or insertional mutagenesis. However, no compensation was found in the PDAT knockout mutant. The effect of PDAT knockout was evaluated in a Δvtc1 mutant, in which PDAT was upregulated under stress, resulting in a 90% increase in TAG content. Knockout of PDAT in the Δvtc1 background induced a 12.8-fold upregulation of DGTT1 and a 272.3% increase in TAG content in Δvtc1/pdat1 cells, while remaining viable. These data suggest that genetic compensation contributes to the genetic robustness of microalgal TAG biosynthetic pathways, maintaining lipid and redox homeostasis in the knockout mutants under abiotic stress. This work demonstrates examples of genetic compensation in microalgae, implies the physiological relevance of genetic compensation in TAG biosynthesis under stress, and provides guidance for future genetic engineering and mutant characterization efforts.