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Eastern newts (Notophthalmus viridescens) upregulate the metabolic capacity of skeletal muscle in winter to compensate for thermodynamic effects on metabolism. However, whether this compensation facilitates locomotor performance at low temperature is unknown. Therefore, our aim was to determine if thermal acclimation of metabolic enzymes in muscle benefits locomotion. Eastern newts from southern Ohio...
Aggression can alter infectious disease dynamics through two, non‐exclusive mechanisms: 1) increasing direct contact among hosts and 2) altering hosts' physiological response to pathogens. Here we examined the latter mechanism in a social songbird by manipulating intraspecific aggression in the absence of direct physical contact. We asked whether the extent of aggression an individual experiences...
Although dietary lipid quality markedly affects fatty acid (FA) composition of mitochondrial membranes from rainbow trout red muscle (Oncorhynchus mykiss), mitochondrial processes are relatively unchanged. As certain classes of phospholipids interact more intimately with membrane proteins than others, we examined whether specific phospholipid classes from these muscle mitochondria were more affected...
Free‐living aquatic embryos are often at risk of exposure to ultraviolet radiation (UV‐R). Successful completion of embryonic development depends on efficient removal of DNA lesions, and thus many aquatic embryos have mechanisms to reverse DNA lesions induced by UV‐R. However, little is known of how embryos that are able to enter embryonic dormancy may respond to UV‐R exposure and subsequent DNA damage...
Sharks have cartilaginous elements that support the jaws and are subjected to variable loads. The aim of this study was to understand how these elements, the hyomandibulae, respond to compressive loads, and to describe the structural level mechanical properties of mineralized cartilage. Mechanical stiffness and effective Poisson's ratio of the hyomandibular cartilage were measured in four species...
This study aimed to develop sex reversal procedures targeting the embryonic period as tools to study the early steps of sex differentiation in Nile tilapia with XX, XY, and YY sexual genotypes. XX eggs were exposed to masculinizing treatments with androgens (17α‐methyltestosterone, 11‐ketotestosterone) or aromatase inhibitor (Fadrozole), whereas XY and YY eggs were subjected to feminizing treatments...
A smad nuclear interacting protein 1 (SNIP1) homolog was identified in the crayfish Procambarus clarkii and this gene encoded a polypeptide of 288 amino acids. Phylogenic analysis showed that P. clarkii SNIP1 was highly homologous to that of invertebrates and shared a highly conserved FHA domain of SNIP proteins at the C‐terminus. Quantitative real‐time PCR (qRT‐PCR) analysis showed that Pc‐SNIP1...
Both latitude and mating system have been proposed to shape relationships between steroid hormone levels and social behavior. Recently it has been postulated that species with long lasting non‐seasonal territorial behavior have low androgen responsiveness. Tropical damselfishes are an ideal family to test this proposition because they show a large variety in mating systems. Here we contribute to the...
Animals inhabiting urban areas must simultaneously cope with the unique challenges presented by this novel habitat type while exploiting the distinctive opportunities it offers. The costs and benefits of urban living are often assumed to be consistent across time, but may in fact vary depending on the habitat features influencing them. Here we examine the glucocorticoid levels and body condition of...
The level of dietary protein determines the onset of reproduction, affects offspring growth and maturation, and hence influences life‐history traits and fitness. However, to date, the long‐term life‐history consequences of protein deficiency are not well understood. We studied the transgenerational effects of different levels of dietary protein on the life‐history and level of maternal behavior of...
The crustacean hyperglycaemic hormone (CHH), a pleiotropic neuropeptide, belongs to a family of structurally related peptides, having six cysteine residues in conserved positions forming three disulphide bridges, and regulating several physiological processes in crustaceans and insects. Structure‐activity studies have shown that amidation of the C‐terminus is important to confer biological activity...
The wood frog, Rana sylvatica LeConte 1825, is a freeze‐tolerant amphibian widely distributed in North America. Subarctic populations of this species can survive experimental freezing to temperatures below −16 °C, whereas temperate populations tolerate freezing only at temperatures above −6 °C. We investigated whether hepatocytes isolated from frogs indigenous to Interior Alaska (subarctic) or southern...
Although many studies have reported the occurrence of testis‐ova in wild frog populations, the origin and trigger of testis‐ova differentiation/development remain unclear. A high frequency of testis‐ova has been previously reported for wild populations of the Japanese pond frog, Rana nigromaculata (cf. Iwasawa and Asai, '59). In the present study, we aimed to clarify the dynamics of testis‐ova in...
Climate change may subject animals to increasingly stressful environmental conditions, which could have negative physiological consequences if stress levels are elevated for long periods. We conducted a manipulative experiment to determine the effects of a novel climate on stress levels and immune function in a model reptile species, the painted turtle. We collected turtles from four populations across...
Progression of the vernal migratory life history stage to breeding presents a number of different behavioral and physiological changes. Long‐distance passerine migrants deposit substantial fat stores to fuel their migratory journey. Many of those migratory birds arrive at their northerly breeding grounds with larger fat stores than other birds. In the current study, plasma metabolites were used to...
The extent to which interactions between environmental stressors and phenotypic variation during larval life stages impose carry‐over effects on adult phenotypes in wildlife are not clear. Using semi‐natural mesocosms, we examined how chronically low food availability and size‐specific phenotypes in larval amphibians interact and carry over to influence frog growth, resource allocation, endocrine...
The present experiments investigated the effect of water quality characteristics on the condition factor, the ovarian activity, cortisol level, and the immunoreactivity of stress‐response cells (adrenocorticotropic hormone; ACTH‐ and melanin stimulating hormone; MSH‐ and somatolactin; SL‐ secreting cells) and gonadotropin (GTH)‐secreting cells in the pituitary gland of Nile tilapia, Oreochromis niloticus...
Several studies suggested that in anuran amphibians steroidogenic enzymes are critical for gonadal differentiation, proposing that the amount of sex steroids would adjust this differentiation. Among anurans, bufonids are important for the study of sex differentiation due to the presence of Bidder's organ (BO) that differentiates as a rudimentary ovary in the cephalic portion of the genital ridge....
Swimming in fishes is powered by myotomal red, white and pink skeletal muscle. Slow swimming is powered by the red (slow‐twitch muscle), fast speeds are achieved by the white (fast‐twitch) muscle and pink muscle apparently serves an intermediate function. In recent years, the physiological properties and molecular composition of red (slow) and white (fast) muscle fibers have been well studied, while...
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