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Enhancing populations of suspension feeding bivalves, particularly the eastern oyster, Crassostrea virginica , has been proposed as a means of mitigating eutrophication in coastal waters. Review of studies evaluating the effects of C. virginica on nitrogen (N) cycling found that oysters can have effects on water quality that vary by orders of magnitude among sites, seasons, and growing condition (e.g., oyster reefs, aquaculture). Nitrogen contained in phytoplankton consumed by oysters may be returned to the water column, assimilated into oyster tissue and shell, buried in the sediments, or returned to the atmosphere as dinitrogen gas, primarily via denitrification. Accurately quantifying oyster-related N removal requires detailed knowledge of these primary fates of N in coastal waters. A review of existing data demonstrated that the current state of knowledge is incomplete in many respects. Nitrogen assimilated into oyster tissue and shell per gram of dry weight was generally similar across sites and in oysters growing on reefs compared to aquaculture. Data on long-term burial of N associated with oyster reefs or aquaculture are lacking. When compared to suitable reference sites, denitrification rates were not consistently enhanced. Depending on environmental and oyster growing conditions, changes in denitrification rates varied by orders of magnitude among studies and did not always occur. Oyster aquaculture rarely enhanced denitrification. Unharvested oyster reefs frequently enhanced denitrification rates. Incorporating oysters into nutrient reduction strategies will require filling gaps in existing data to determine the extent to which relationships between N removal and environmental and/or growing conditions can be generalized. [ABSTRACT FROM AUTHOR]

Alabama (AL) is a hotspot in the Gulf of Mexico (GoM) for human interaction-related cetacean strandings, including harassment, vessel strikes, and fisheries interactions. We examined four bottlenose dolphins ( Tursiops truncatus ) stranded dead along the AL coast during 2012-2017 with severed peduncles suspected to be related to human interaction (HI). Evidence from each case, including photographs, gross necropsy results, and histopathologic findings when available, was reviewed to determine the mode of severance and whether it contributed to death. In each case, the severance site had smooth, clean edges on at least one side, indicating the use of a sharp instrument to remove the caudal peduncle and flukes. Three cases also had evidence of fisheries interactions, including linear impressions around the rostrum, fins and/or flukes, indicating that these animals may have been entangled in fisheries gear prior to death. Histopathology in one of these cases revealed that the severance occurred perimortem; speculatively, the caudal peduncle and flukes may have been cut off to facilitate removing the dolphin from its entanglement. Although cases of amputation and mutilation are not uncommon globally among stranding reports, few cases have been described and analyzed in the literature. This paper is the first to document and compare multiple cases of severed peduncles with evidence of HI, including fisheries, in the GoM. This case series enhances our understanding of the types of HI occurring in bottlenose dolphins and highlights the need for continued public education, policy, and management to address cases like these.

Peroxisomes are highly dynamic, oxidative organelles with key metabolic functions in cellular lipid metabolism, such as the β-oxidation of fatty acids and the synthesis of myelin sheath lipids, as well as the regulation of cellular redox balance. Loss of peroxisomal functions causes severe metabolic disorders in humans. Furthermore, peroxisomes also fulfil protective roles in pathogen and viral defence and immunity, highlighting their wider significance in human health and disease. This has sparked increasing interest in peroxisome biology and their physiological functions. This review presents an update and a continuation of three previous review articles addressing the unsolved mysteries of this remarkable organelle. We continue to highlight recent discoveries, advancements, and trends in peroxisome research, and address novel findings on the metabolic functions of peroxisomes, their biogenesis, protein import, membrane dynamics and division, as well as on peroxisome-organelle membrane contact sites and organelle cooperation. Furthermore, recent insights into peroxisome organisation through super-resolution microscopy are discussed. Finally, we address new roles for peroxisomes in immune and defence mechanisms and in human disorders, and for peroxisomal functions in different cell/tissue types, in particular their contribution to organ-specific pathologies., (© 2024. The Author(s).)

Perfluorooctane sulfonate (PFOS) is a ubiquitous pollutant that elicits a wide range of toxic effects in exposed biota. Coastal zones in highly urbanized or industrial areas are particularly vulnerable to PFOS pollution. At present, information is lacking on biomarkers to assess PFOS effects on aquatic wildlife. This study investigated the efficacy of l-carnitine (or carnitine) and fatty acids as biomarkers of PFOS exposure in aquatic biota. The levels of PFOS, total and free carnitine, and 24 fatty acids (measured as fatty acid methyl esters or FAMEs) were measured in the liver, and muscle or blubber, of fish and dolphins sampled from Galveston Bay and the northern Gulf of Mexico (nGoM). Overall, bottlenose dolphins (Tursiops truncatus) had the highest hepatic PFOS levels. Galveston Bay fish, gafftopsail catfish (Bagre marinus), red drum (Sciaenops ocellatus), and spotted seatrout (Cynoscion nebulosus), had hepatic PFOS levels ∼8-13× higher than nGoM pelagic fish species, red snapper (Lutjanus campechanus) and yellowfin tuna (Thunnus albacares). The multivariate analysis of PFOS liver body-burdens and biomarkers found carnitine to be a more modal biomarker of PFOS exposure than FAMEs. Significant positive correlation of hepatic PFOS levels with total carnitine was evident for biota from Galveston Bay (fish only), and a significant correlation between PFOS and total and free carnitine was evident for biota from the nGoM (fish and dolphins). Given the essential role of carnitine in mediating fatty acid β-oxidation, our results suggest carnitine to be a likely candidate biomarker of environmental PFOS exposure and indicative of potential dyslipidemia effects., Competing Interests: Declaration of competing interest The authors whose names are listed immediately below certify that they have NO affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers' bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Scombrotoxin (histamine) fish poisoning is a common seafood-borne illness attributed to toxin production by histamine-producing bacteria (HPB) in fish tissues during decomposition. In laboratory studies, growth of HPB and other bacterial species is affected by physical and chemical attributes, but natural communities of HPB are not well understood. To determine how in situ environmental and water quality variables may affect density of HPB in the natural aquatic environment, we compared presence and abundance of HPB to ambient temperature, salinity, dissolved oxygen, fecal coliforms, male-specific coliphage, nutrient concentrations, carbon and nitrogen stable isotope ratios, and C:N in water samples collected from July 2017 to February 2018 along a natural salinity gradient in a tidal river on the coast of northern Gulf of Mexico. HPB in water samples were quantified using a real-time PCR, most probable number method. HPB species were identified via 16S rRNA gene sequences. Temperature and salinity were determined to be the main factors driving HPB presence and concentration. Canonical correspondence analysis revealed that different HPB were associated with different environmental conditions. Photobacterium damselae was found under warmer, higher-salinity conditions; Raoultella planticola was found at colder, lower-salinity conditions; Enterobacter aerogenes was found at warmer, lower-salinity conditions; and Morganella morganii was found at most sites, independent of environmental conditions. These results showed that naturally occurring HPB abundance and species composition can be affected by environmental conditions, which could manifest in various potentials for histamine formation and scombrotoxin fish poisoning risk based on environmental factors. IMPORTANCE This study determined the effects of environmental conditions on presence and abundance of naturally occurring histamine-producing bacteria in the northern Gulf of Mexico. Here, we show that HPB abundance and species composition are related to in situ ambient temperature and salinity, with the magnitude of this effect dependent on the particular HPB species. This finding suggests that environmental conditions at fishing sites could affect the risk of human illness from scombrotoxin (histamine) fish poisoning., Competing Interests: The authors declare no conflict of interest.

Organelles within eukaryotic cells are not isolated static compartments, instead being morphologically diverse and highly dynamic in order to respond to cellular needs and carry out their diverse and cooperative functions. One phenomenon exemplifying this plasticity, and increasingly gaining attention, is the extension and retraction of thin tubules from organelle membranes. While these protrusions have been observed in morphological studies for decades, their formation, properties and functions are only beginning to be understood. In this review, we provide an overview of what is known and still to be discovered about organelle membrane protrusions in mammalian cells, focusing on the best-characterised examples of these membrane extensions arising from peroxisomes (ubiquitous organelles involved in lipid metabolism and reactive oxygen species homeostasis) and mitochondria. We summarise the current knowledge on the diversity of peroxisomal/mitochondrial membrane extensions, as well as the molecular mechanisms by which they extend and retract, necessitating dynamic membrane remodelling, pulling forces and lipid flow. We also propose broad cellular functions for these membrane extensions in inter-organelle communication, organelle biogenesis, metabolism and protection, and finally present a mathematical model that suggests that extending protrusions is the most efficient way for an organelle to explore its surroundings.

Vibrio cholerae is the etiological agent of the illness cholera. However, there are non-O1/non-O139 V. cholerae (NOVC) strains that generally lack the toxin gene ( ctx ) and colonization factors that cause cholera. These NOVC strains are autochthonous members of estuarine environments and a significant cause of seafood-borne gastroenteritis in the United States. The objective of this study was to identify environmental parameters that correlate with NOVC prevalence in oysters, water, and sediment at three ecologically diverse locations in Mobile Bay, AL, including Dog River (DR), Fowl River (FR), and Cedar Point (CP). Oyster, water, and sediment samples were collected twice a month when conditions were favorable for NOVC growth and once a month when they were not. A most probable number (MPN)/real-time PCR assay was used to determine NOVC abundances. Environmental parameters were measured during sampling to determine their relationship, if any, with NOVC at each site. NOVC abundances in oysters at DR, FR, and CP were 0.87, 0.87, and -0.13 log MPN/g, respectively. In water, the median NOVC levels at DR, FR, and CP were 1.18, -0.13, and -0.82 log MPN/mL, and in sediment, the levels were 1.48, 1.87, and -0.03 log MPN/g, respectively. Correlations of NOVC abundances in oyster, water, and sediment samples with environmental parameters were largely site specific. For example, the levels of NOVC in oysters at DR had a positive correlation with temperature but a negative correlation with dissolved oxygen (DO) and nutrient concentrations, NO 2 - , NO 3 - , dissolved inorganic nitrogen (DIN), total dissolved nitrogen (TDN), and dissolved inorganic phosphorus (DIP). At FR, however, the levels of NOVC in oysters displayed only a negative correlation with NO 2 - . When grouping NOVC abundances by temperature, the main driving factor for prevalence, additional correlations with salinity, total cell counts, dissolved organic nitrogen (DON), and dissolved organic carbon (DOC) became evident regardless of the site. IMPORTANCE NOVC can cause gastrointestinal illness in humans, which typically occurs after the consumption of raw or undercooked seafood. Incidence rates of NOVC gastroenteritis have increased during the past decade. In this study, NOVC was enumerated from oysters, sediment, and water collected at three sites in Mobile Bay, with environmental parameters measured concurrently over the course of a year, to identify potential environmental drivers of NOVC abundances. The data from this study, from an area lacking in V. cholerae research, provide a useful baseline for risk analysis of V. cholerae infections. Defining correlations between NOVC and environmental attributes at different sites and temperatures within a dynamic system such as Mobile Bay provides valuable data to better understand the occurrence and proliferation of V. cholerae in the environment.

Peroxisomes are multifunctional, ubiquitous, and dynamic organelles. They are responsible for diverse metabolic and physiological functions and communicate with other organelles, including the ER, mitochondria, lipid droplets, and lysosomes, through membrane contact sites. However, despite their importance for healthy cell function, remarkably, little is known about how peroxisomes and peroxisomal proteins are regulated under physiological conditions in human cells. Here, we present a method to generate reporter cell lines to measure endogenous expression of peroxisomal proteins of interest. By CRISPR-mediated knock-in of an easily detectable protein-coding tag in-frame into the relevant genomic loci, endogenous levels of the protein of interest in a cell population can be quantified in a high-throughput manner under different conditions. This has important implications for the fundamental understanding of how peroxisomal proteins are regulated and may reveal the therapeutic potential of modulating peroxisomal protein expression to improve cell performance., (© 2023. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Peroxisomes are dynamic subcellular organelles in mammals, playing essential roles in cellular lipid metabolism and redox homeostasis. They perform a wide spectrum of functions in human health and disease, with new roles, mechanisms, and regulatory pathways still being discovered. Recently elucidated biological roles of peroxisomes include as antiviral defense hubs, intracellular signaling platforms, immunomodulators, and protective organelles in sensory cells. Furthermore, peroxisomes are part of a complex inter-organelle interaction network, which involves metabolic cooperation and cross talk via membrane contacts. The detection of endogenous and/or overexpressed proteins within a cell by immunolabelling informs us about the organellar and even sub-organellar localization of both known and putative peroxisomal proteins. In turn, this can be exploited to characterize the effects of experimental manipulations on the morphology, distribution, and/or number of peroxisomes in a cell, which are key properties controlling peroxisome function. Here, we present a protocol used successfully in our laboratory for the immunolabelling of peroxisomal proteins in cultured mammalian cells. We present immunofluorescence and transfection techniques as well as reagents to determine the localization of endogenous and overexpressed peroxisomal proteins., (© 2023. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Peroxisome membrane dynamics and division are essential to adapt the peroxisomal compartment to cellular needs. The peroxisomal membrane protein PEX11β (also known as PEX11B) and the tail-anchored adaptor proteins FIS1 (mitochondrial fission protein 1) and MFF (mitochondrial fission factor), which recruit the fission GTPase DRP1 (dynamin-related protein 1, also known as DNML1) to both peroxisomes and mitochondria, are key factors of peroxisomal division. The current model suggests that MFF is essential for peroxisome division, whereas the role of FIS1 is unclear. Here, we reveal that PEX11β can promote peroxisome division in the absence of MFF in a DRP1- and FIS1-dependent manner. We also demonstrate that MFF permits peroxisome division independently of PEX11β and restores peroxisome morphology in PEX11β-deficient patient cells. Moreover, targeting of PEX11β to mitochondria induces mitochondrial division, indicating the potential for PEX11β to modulate mitochondrial dynamics. Our findings suggest the existence of an alternative, MFF-independent pathway in peroxisome division and report a function for FIS1 in the division of peroxisomes. This article has an associated First Person interview with the first authors of the paper., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2022. Published by The Company of Biologists Ltd.)

Peroxisomes are highly dynamic and responsive organelles, which can adjust their morphology, number, intracellular position, and metabolic functions according to cellular needs. Peroxisome multiplication in mammalian cells involves the concerted action of the membrane-shaping protein PEX11β and division proteins, such as the membrane adaptors FIS1 and MFF, which recruit the fission GTPase DRP1 to the peroxisomal membrane. The latter proteins are also involved in mitochondrial division. Patients with loss of DRP1, MFF or PEX11β function have been identified, showing abnormalities in peroxisomal (and, for the shared proteins, mitochondrial) dynamics as well as developmental and neurological defects, whereas the metabolic functions of the organelles are often unaffected. Here, we provide a timely update on peroxisomal membrane dynamics with a particular focus on peroxisome formation by membrane growth and division. We address the function of PEX11β in these processes, as well as the role of peroxisome-ER contacts in lipid transfer for peroxisomal membrane expansion. Furthermore, we summarize the clinical phenotypes and pathophysiology of patients with defects in the key division proteins DRP1, MFF, and PEX11β as well as in the peroxisome-ER tether ACBD5. Potential therapeutic strategies for these rare disorders with limited treatment options are discussed.

Mitochondria are unavoidably subject to organellar stress resulting from exposure to a range of reactive molecular species. Consequently, cells operate a poorly understood quality control programme of mitophagy to facilitate elimination of dysfunctional mitochondria. Here, we used a model stressor, deferiprone (DFP), to investigate the molecular basis for stress-induced mitophagy. We show that mitochondrial fission 1 protein (Fis1) is required for DFP-induced mitophagy and that Fis1 is SUMOylated at K149, an amino acid residue critical for Fis1 mitochondrial localization. We find that DFP treatment leads to the stabilization of the SUMO protease SENP3, which is mediated by downregulation of the E3 ubiquitin (Ub) ligase CHIP. SENP3 is responsible for Fis1 deSUMOylation and depletion of SENP3 abolishes DFP-induced mitophagy. Furthermore, preventing Fis1 SUMOylation by conservative K149R mutation enhances Fis1 mitochondrial localization. Critically, expressing a Fis1 K149R mutant restores DFP-induced mitophagy in SENP3-depleted cells. Thus, we propose a model in which SENP3-mediated deSUMOylation facilitates Fis1 mitochondrial localization to underpin stress-induced mitophagy., (© 2022 The Authors. Published under the terms of the CC BY 4.0 license.)

Organelles within the cell are highly dynamic entities, requiring dramatic morphological changes to support their function and maintenance. As a result, organelle membranes are also highly dynamic, adapting to a range of topologies as the organelle changes shape. In particular, peroxisomes-small, ubiquitous organelles involved in lipid metabolism and reactive oxygen species homeostasis-display a striking plasticity, for example, during the growth and division process by which they proliferate. During this process, the membrane of an existing peroxisome elongates to form a tubule, which then constricts and ultimately undergoes scission to generate new peroxisomes. Dysfunction of this plasticity leads to diseases with developmental and neurological phenotypes, highlighting the importance of peroxisome dynamics for healthy cell function. What controls the dynamics of peroxisomal membranes, and how this influences the dynamics of the peroxisomes themselves, is just beginning to be understood. In this review, we consider how the composition, biophysical properties, and protein-lipid interactions of peroxisomal membranes impacts on their dynamics, and in turn on the biogenesis and function of peroxisomes. In particular, we focus on the effect of the peroxin PEX11 on the peroxisome membrane, and its function as a major regulator of growth and division. Understanding the roles and regulation of peroxisomal membrane dynamics necessitates a multidisciplinary approach, encompassing knowledge across a range of model species and a number of fields including lipid biochemistry, biophysics and computational biology. Here, we present an integrated overview of our current understanding of the determinants of peroxisome membrane dynamics, and reflect on the outstanding questions still remaining to be solved., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Carmichael and Schrader.)

Defining the molecular changes that underlie Alzheimer's disease (AD) is an important question in neuroscience. Here, we examined changes in protein SUMOylation, and proteins involved in mitochondrial dynamics, in an in vitro model of AD induced by application of amyloid-β 1-42 (Aβ 1-42 ) to cultured neurons. We observed Aβ 1-42 -induced decreases in global SUMOylation and in levels of the SUMO pathway enzymes SENP3, PIAS1/2, and SAE2. Aβ exposure also decreased levels of the mitochondrial fission proteins Drp1 and Mff and increased activation of caspase-3. To examine whether loss of SENP3 is cytoprotective we knocked down SENP3, which partially prevented the Aβ 1-42 -induced increase in caspase-3 activation. Together, these data support the hypothesis that altered SUMOylation may play a role in the mechanisms underlying AD., Competing Interests: None., (© 2022 The Authors. Published by Elsevier Ltd on behalf of International Brain Research Organization.)

Mobile, apex predators are commonly assumed to stabilize food webs through trophic coupling across spatially distinct habitats. The assumption that trophic coupling is common remains largely untested, despite evidence that individual behaviors might limit trophic coupling. We used stable isotope data from common bottlenose dolphins across the Gulf of Mexico to determine if these apex predators coupled estuarine and adjacent, nearshore marine habitats. δ 13 C values differed among the sites, likely driven by environmental factors that varied at each site, such as freshwater input and seagrass cover. Within most sites, δ 13 C values differed such that dolphins sampled in the upper reaches of embayments had values indicative of estuarine habitats while those sampled outside or in lower reaches of embayments had values indicative of marine habitats. δ 15 N values were more similar among and within sites than δ 13 C values. Data from multiple tissues within individuals corroborated that most dolphins consistently used a narrow range of habitats but fed at similar trophic levels in estuarine and marine habitats. Because these dolphins exhibited individual habitat specialization, they likely do not contribute to trophic coupling between estuarine and adjacent marine habitats at a regional scale, suggesting that not all mobile, apex predators trophically couple adjacent habitats., (© 2021. The Author(s).)

In mammals, peroxisomes perform crucial functions in cellular metabolism, signaling and viral defense which are essential to the viability of the organism. Molecular cues triggered by changes in the cellular environment induce a dynamic response in peroxisomes, which manifests itself as a change in peroxisome number, altered enzyme levels and adaptations to the peroxisomal morphology. How the regulation of this process is integrated into the cell's response to different stimuli, including the signaling pathways and factors involved, remains unclear. Here, a cell-based peroxisome proliferation assay has been applied to investigate the ability of different stimuli to induce peroxisome proliferation. We determined that serum stimulation, long-chain fatty acid supplementation and TGFβ application all increase peroxisome elongation, a prerequisite for proliferation. Time-resolved mRNA expression during the peroxisome proliferation cycle revealed a number of peroxins whose expression correlated with peroxisome elongation, including the β isoform of PEX11, but not the α or γ isoforms. An initial map of putative regulatory motif sites in the respective promoters showed a difference between binding sites in PEX11α and PEX11β, suggesting that these genes may be regulated by distinct pathways. A functional SMAD2/3 binding site in PEX11β points to the involvement of the TGFβ signaling pathway in expression of this gene and thus peroxisome proliferation/dynamics in humans., (Copyright © 2020 Azadi, Carmichael, Kovacs, Koster, Kors, Waterham and Schrader.)

There have been efforts around the globe to track individuals of many marine species and assess their movements and distribution, with the putative goal of supporting their conservation and management. Determining whether, and how, tracking data have been successfully applied to address real-world conservation issues is, however, difficult. Here, we compile a broad range of case studies from diverse marine taxa to show how tracking data have helped inform conservation policy and management, including reductions in fisheries bycatch and vessel strikes, and the design and administration of marine protected areas and important habitats. Using these examples, we highlight pathways through which the past and future investment in collecting animal tracking data might be better used to achieve tangible conservation benefits., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Type-II Diabetes Mellitus (T2DM) is one of the fastest growing public health issues today, consuming 12% of worldwide health budgets and affecting an estimated 400 million people. One of the key pathological traits of this disease is insulin resistance at 'glucose sink' tissues (mostly skeletal muscle), and this remains one of the features of this disease most intractable to therapeutic intervention. Several lines of evidence have implicated the post-translational modification, SUMOylation, in insulin signalling and insulin resistance in skeletal muscle. In this study, we examined this possibility by manipulation of cellular SUMOylation levels using multiple different tools, and assaying the effect on insulin-stimulated GLUT4 surface expression in differentiated L6 rat myocytes. Although insulin stimulation of L6 myocytes produced a robust decrease in total cellular SUMO1-ylation levels, manipulating cellular SUMOylation had no effect on insulin-responsive GLUT4 surface trafficking using any of the tools we employed. Whilst we cannot totally exclude the possibility that SUMOylation plays a role in the insulin signalling pathway in human health and disease, our data strongly argue that GLUT4 trafficking in response to insulin is not regulated by protein SUMOylation, and that SUMOylation does not therefore represent a viable therapeutic target for the treatment of insulin resistance.

Type-II Diabetes Mellitus (T2DM) is one of the fastest growing public health issues of modern times, consuming 12% of worldwide health budgets and affecting an estimated 400 million people. A key pathological trait associated with this disease is the failure of normal glucose-stimulated insulin secretion (GSIS) from pancreatic beta cells. Several lines of evidence suggest that vesicle trafficking events such as insulin secretion are regulated by the post-translational modification, SUMOylation, and indeed SUMOylation has been proposed to act as a 'brake' on insulin exocytosis. Here, we show that diabetic stimuli which inhibit GSIS are correlated with an increase in cellular protein SUMOylation, and that inhibition of deSUMOylation reduces GSIS. We demonstrate that manipulation of cellular protein SUMOylation levels, by overexpression of several different components of the SUMOylation pathway, have varied and complex effects on GSIS, indicating that SUMOylation regulates this process at multiple stages. We further demonstrate that inhibition of syntaxin1A SUMOylation, via a knockdown-rescue strategy, greatly enhances GSIS. Our data are therefore consistent with the model that SUMOylation acts as a brake on GSIS, and we have identified SUMOylation of syntaxin 1 A as a potential component of this brake. However, our data also demonstrate that the role of SUMOylation in GSIS is complex and may involve many substrates.

An unusual mortality event (UME) involving primarily common bottlenose dolphins Tursiops truncatus of all size classes stranding along coastal Louisiana, Mississippi, and Alabama, USA, started in early 2010 and continued into 2014. During this northern Gulf of Mexico UME, a distinct cluster of perinatal dolphins (total body length <115 cm) stranded in Mississippi and Alabama during 2011. The proportion of annual dolphin strandings that were perinates between 2009 and 2013 were compared to baseline strandings (2000-2005). A case-reference study was conducted to compare demographics, histologic lesions, and Brucella sp. infection prevalence in 69 UME perinatal dolphins to findings from 26 reference perinates stranded in South Carolina and Florida outside of the UME area. Compared to reference perinates, UME perinates were more likely to have died in utero or very soon after birth (presence of atelectasis in 88 vs. 15%, p < 0.0001), have fetal distress (87 vs. 27%, p < 0.0001), and have pneumonia not associated with lungworm infection (65 vs. 19%, p = 0.0001). The percentage of perinates with Brucella sp. infections identified via lung PCR was higher among UME perinates stranding in Mississippi and Alabama compared to reference perinates (61 vs. 24%, p = 0.01), and multiple different Brucella omp genetic sequences were identified in UME perinates. These results support that from 2011 to 2013, during the northern Gulf of Mexico UME, bottlenose dolphins were particularly susceptible to late-term pregnancy failures and development of in utero infections including brucellosis.

An unusual mortality event (UME) was declared for cetaceans in the northern Gulf of Mexico (GoM) for Franklin County, Florida, west through Louisiana, USA, beginning in February 2010 and was ongoing as of September 2014. The 'Deepwater Horizon' (DWH) oil spill began on 20 April 2010 in the GoM, raising questions regarding the potential role of the oil spill in the UME. The present study reviews cetacean mortality events that occurred in the GoM prior to 2010 (n = 11), including causes, durations, and some specific test results, to provide a historical context for the current event. The average duration of GoM cetacean UMEs prior to 2010 was 6 mo, and the longest was 17 mo (2005-2006). The highest number of cetacean mortalities recorded during a previous GoM event was 344 (in 1990). In most previous events, dolphin morbillivirus or brevetoxicosis was confirmed or suspected as a causal factor. In contrast, the current northern GoM UME has lasted more than 48 mo and has had more than 1000 reported mortalities within the currently defined spatial and temporal boundaries of the event. Initial results from the current UME do not support either morbillivirus or brevetoxin as primary causes of this event. This review is the first summary of cetacean UMEs in the GoM and provides evidence that the most common causes of previous UMEs are unlikely to be associated with the current UME.

Timely and efficient information transfer at synapses is fundamental to brain function. Synapses are highly dynamic structures that exhibit long-lasting activity-dependent alterations to their structure and transmission efficiency, a phenomenon termed synaptic plasticity. These changes, which occur through alterations in presynaptic release or in the trafficking of postsynaptic receptor proteins, underpin the formation and stabilisation of neural circuits during brain development, and encode, process and store information essential for learning, memory and cognition. In recent years, it has emerged that the ubiquitin-like posttranslational modification SUMOylation is an important mediator of several aspects of neuronal and synaptic function. Through orchestrating synapse formation, presynaptic release and the trafficking of postsynaptic receptor proteins during forms of synaptic plasticity such as long-term potentiation, long-term depression and homeostatic scaling, SUMOylation is being increasingly appreciated to play a central role in neurotransmission. In this review, we outline key discoveries in this relatively new field, provide an update on recent progress regarding the targets and consequences of protein SUMOylation in synaptic function and plasticity, and highlight key outstanding questions regarding the roles of protein SUMOylation in the brain.