Immune Defense in Hypoxic Waters: Impacts of CO Acidification.

AbstractPeriodic episodes of low oxygen (hypoxia) and elevated CO (hypercapnia) accompanied by low pH occur naturally in estuarine environments. Under the influence of climate change, the geographic range and intensity of hypoxia and hypercapnic hypoxia are predicted to increase, potentially jeopardizing the survival of economically and ecologically important organisms that use estuaries as habitat and nursery grounds. In this review we synthesize data from published studies that evaluate the impact of hypoxia and hypercapnic hypoxia on the ability of crustaceans and bivalve molluscs to defend themselves against potential microbial pathogens.

Performance and safety of treatment options for erectile dysfunction in patients with spinal cord injury: A review of the literature.

Background: For a large proportion of patients with spinal cord injury, sexuality and reproduction are important issues. However, sparse data exist regarding available treatment options for this patient population.

Objectives: We sought to review performance and safety rates of all currently available treatment options for erectile dysfunction in spinal cord injury men.

Physiological impacts of time in holding ponds, biomedical bleeding, and recovery on the Atlantic horseshoe crab, Limulus polyphemus.

Atlantic horseshoe crabs, Limulus polyphemus (HSC), are commercially harvested along the eastern U.S. coast and bled for hemolymph used in pharmaceutical safety testing.

Effects of Hypoxia and Hypercapnic Hypoxia on Oxygen Transport and Acid-Base Status in the Atlantic Blue Crab, Callinectes sapidus, During Exercise.

The responses of estuarine invertebrates to hypoxic conditions are well established. However, many studies have investigated hypoxia as an isolated condition despite its frequent co-occurrence with hypercapnia (elevated CO ). Although many studies suggest deleterious effects, hypercapnia has been observed to improve blue crab walking performance in hypoxia.

Uncovering Hemocyanin Subunit Heterogeneity in Penaeid Shrimp using RNA-Seq.

Aquatic crustaceans can experience low levels of O alone but more often in combination with high levels of CO both in natural estuaries and in aquaculture ponds. Hemocyanin, the respiratory pigment in many crustacean species, facilitates O transport and is documented to change in abundance, structure, and function in response to low O The impacts of high CO on the respiratory pigment are less clear. In this synthesis we bring together data from recently published and new RNA-Seq studies toward the aims of defining the full repertoire of hemocyanin subunits, as well as their differential expression and regulation in the Penaeoidea family in response to low O with or without high CO RNA-Seq data were collected from the hepatopancreas tissues of aquacultured Pacific whiteleg shrimp Litopenaeus vannamei, wild-caught L.

High CO2 alters the hypoxia response of the Pacific whiteleg shrimp (Litopenaeus vannamei) transcriptome including known and novel hemocyanin isoforms.

Acclimation to low O2 in many organisms involves changes at the level of the transcriptome. Here we used high-throughput RNA sequencing (RNA-Seq) to explore the global transcriptomic response and specific involvement of a suite of hemocyanin (Hc) subunits to low O2 alone and in combination with high CO2, which naturally co-occurs with low O2. Hepatopancreas mRNA of juvenile L.

Respiratory and Metabolic Impacts of Crustacean Immunity: Are there Implications for the Insects?

Extensive similarities in the molecular architecture of the crustacean immune system to that of insects give credence to the current view that the Hexapoda, including Insecta, arose within the clade Pancrustacea. The crustacean immune system is mediated largely by hemocytes, relying on suites of pattern recognition receptors, effector functions, and signaling pathways that parallel those of insects. In crustaceans, as in insects, the cardiovascular system facilitates movement of hemocytes and delivery of soluble immune factors, thereby supporting immune surveillance and defense along with other physiological functions such as transport of nutrients, wastes, and hormones.

Respiratory Properties of Hemocyanin From Wild and Aquacultured Penaeid Shrimp and the Effects of Chronic Exposure to Hypoxia.

Properties of hemocyanins vary greatly among crustaceans due to environmental conditions, lifestyle, and genetic variation. These properties can also be modified to maintain aerobic respiration in response to ambient hypoxia, as experienced by both aquacultured and wild populations of penaeid shrimp. Under normoxic conditions, hemocyanin concentrations were significantly higher (P < 0.

Effects of salinity on the accumulation of hemocyte aggregates and bacteria in the gills of Callinectes sapidus, the Atlantic blue crab, injected with Vibrio campbellii.

In addition to respiration and ion regulation, crustacean gills accumulate and eliminate injected particles, along with hemocyte aggregates that form in response to those particles. Here we report that the dose of Vibrio campbellii previously shown to induce a decrease in respiration and hemolymph flow across the gill in the Atlantic blue crab, Callinectes sapidus, also triggered the formation of aggregates containing four or more hemocytes in the gills, compared with saline-injected controls. More bacteria were trapped and rendered non-culturable per unit weight by anterior respiratory gills than posterior gills specialized for ion regulation.

Recovery from hypoxia and hypercapnic hypoxia: impacts on the transcription of key antioxidants in the shrimp Litopenaeus vannamei.

Estuarine waters are prone to regular bouts of low oxygen (hypoxia) and high carbon dioxide (hypercapnia). In vertebrates, tissue hypoxia followed by reoxygenation can generate high levels of reactive oxygen species (ROS) that exceed cellular antioxidant capacity, leading to tissue damage. Here we quantified the expression of several antioxidant genes in the hepatopancreas of Pacific whiteleg shrimp, Litopenaeus vannamei, after exposure to hypoxia or hypercapnic hypoxia for 4h or 24h followed by recovery in air-saturated water (normoxia) for 0, 1, 6 or 24h, as compared to time-matched controls maintained only in normoxia.

Effect of hypercapnic hypoxia and bacterial infection (Vibrio campbellii) on protein synthesis rates in the Pacific whiteleg shrimp, Litopenaeus vannamei.

Estuarine species frequently encounter areas of simultaneously low dissolved O2 (hypoxia) and high CO2 (hypercapnia). Organisms exposed to hypoxia experience a metabolic depression that serves to decrease ATP utilization and O2 demand during stress. This downregulation is typically facilitated by a reduction in protein synthesis, a process that can be responsible for up to 60% of basal metabolism.

Transcriptomic responses of juvenile Pacific whiteleg shrimp, Litopenaeus vannamei, to hypoxia and hypercapnic hypoxia.

Estuarine crustaceans are often exposed to low dissolved O2 (hypoxia) accompanied by elevated CO2 (hypercapnia), which lowers water pH. Acclimatory responses to hypoxia have been widely characterized; responses to hypercapnia in combination with hypoxia (hypercapnic hypoxia) are less well known. Here we used oligonucleotide microarrays to characterize changes in global gene expression in the hepatopancreas of Pacific whiteleg shrimp, Litopenaeus vannamei, exposed to hypoxia or hypercapnic hypoxia for 4 or 24 h, compared with time-matched animals held in air-saturated water (normoxia).

Locomotory fatigue during moderate and severe hypoxia and hypercapnia in the Atlantic blue crab, Callinectes sapidus.

The Atlantic blue crab, Callinectes sapidus (Rathbun), is a highly mobile crustacean that must locomote to find food, evade predators, find mates, and avoid adverse conditions such as hypoxia. In this study we tested the effects of two levels of hypoxia (10.4 kPa, 50% air saturation = moderate hypoxia; 4 kPa, 20% air saturation = severe hypoxia) and hypercapnic hypoxia (50% air saturation O(2) with Pco(2) = 2 kPa) on fatigue during sustained continuous exercise.

Gene transcripts encoding hypoxia-inducible factor (HIF) exhibit tissue- and muscle fiber type-dependent responses to hypoxia and hypercapnic hypoxia in the Atlantic blue crab, Callinectes sapidus.

Hypoxia inducible factor (HIF) is a transcription factor that under low environmental oxygen regulates the expression of suites of genes involved in metabolism, angiogenesis, erythropoiesis, immune function, and growth. Here, we isolated and sequenced partial cDNAs encoding hif-α and arnt/hif-β from the Atlantic blue crab, Callinectes sapidus, an estuarine species that frequently encounters concurrent hypoxia (low O(2)) and hypercapnia (elevated CO(2)). We then examined the effects of acute exposure (1h) to hypoxia (H) and hypercapnic hypoxia (HH) on relative transcript abundance for hif-α and arnt/hif-β in different tissues (glycolytic muscle, oxidative muscle, hepatopancreas, gill, and gonads) using quantitative real-time RT-PCR.

Properties of bacteria that trigger hemocytopenia in the Atlantic blue crab, Callinectes sapidus.

In the blue crab Callinectes sapidus, injection with the bacterial pathogen Vibrio campbellii causes a decrease in oxygen consumption. Histological and physiological evidence suggests that the physical obstruction of hemolymph flow through the gill vasculature, caused by aggregations of bacteria and hemocytes, underlies the decrease in aerobic function associated with bacterial infection. We sought to elucidate the bacterial properties sufficient to induce a decrease in circulating hemocytes (hemocytopenia) as an indicator for the initiation of hemocyte aggregation and subsequent impairment of respiration.

Modelling interactions of acid-base balance and respiratory status in the toxicity of metal mixtures in the American oyster Crassostrea virginica.

Heavy metals, such as copper, zinc and cadmium, represent some of the most common and serious pollutants in coastal estuaries. In the present study, we used a combination of linear and artificial neural network (ANN) modelling to detect and explore interactions among low-dose mixtures of these heavy metals and their impacts on fundamental physiological processes in tissues of the Eastern oyster, Crassostrea virginica. Animals were exposed to Cd (0.

Energy metabolism and metabolic depression during exercise in Callinectes sapidus, the Atlantic blue crab: effects of the bacterial pathogen Vibrio campbellii.

Callinectes sapidus (Rathbun), the Atlantic blue crab, commonly harbors low to moderate amounts of bacteria in hemolymph and other tissues. These bacteria are typically dominated by Vibrio spp., which are known to cause mortality in the blue crab.

Time-course analysis of peroxinectin mRNA in the shrimp Litopenaeus vannamei after challenge with Vibrio campbellii.

Peroxinectin (Pox), which promotes cell adhesion and encapsulation of bacteria in crustaceans, is synthesized in granular and semigranular hemocytes. In this study, real-time PCR was used to quantify Pox transcripts in individual tissues of the Pacific white shrimp, Litopenaeus vannamei, over 48 h following injection of a sublethal dose of the shrimp pathogen Vibrio campbellii. The resulting data were used to infer the movements of hemocytes among the tissues in response to bacterial challenge.

Differential localization and bacteriostasis of Vibrio campbellii among tissues of the Eastern oyster, Crassostrea virginica.

In bivalve mollusks the roles of individual tissues in antimicrobial defense remain unclear. In this study, Crassostrea virginica were injected in the adductor muscle with 10(5) live Vibrio campbellii. Major tissues were dissected at 10, 30, 60 or 120 min postinjection (PI); in each tissue undegraded (intact) bacteria were quantified by real-time PCR and culturable bacteria were enumerated by selective plating.