Feces of harbor seals (Phoca vitulina richardsi) and hybrid glaucous-winged/western gulls (Larus glaucescens / occidentalis) from Washington State's inland marine waters were examined for Giardia and Cryptosporidium spp. to determine if genotypes carried by these wildlife species were the same genotypes that commonly infect humans and domestic animals. Using immunomagnetic separation followed by direct fluorescent antibody detection, Giardia spp. cysts were detected in 42% of seal fecal samples (41/97). Giardia-positive samples came from 90% of the sites (9/10) and the prevalence of positive seal fecal samples differed significantly among study sites. Fecal samples collected from seal haulout sites with over 400 animals were 4.7 times more likely to have Giardia spp. cysts than samples collected at smaller haulout sites. In gulls, a single Giardia sp. cyst was detected in 4% of fecal samples (3/78). Cryptosporidium spp. oocysts were not detected in any of the seals or gulls tested. Sequence analysis of a 398 bp segment of G. duodenalis DNA at the glutamate dehydrogenase locus suggested that 11 isolates originating from seals throughout the region were a novel genotype and 3 isolates obtained from a single site in south Puget Sound were the G. duodenalis canine genotype D. Real-time TaqMan PCR amplification and subsequent sequencing of a 52 bp small subunit ribosomal DNA region from novel harbor seal genotype isolates showed sequence homology to canine genotypes C and D. Sequence analysis of the 52 bp small subunit ribosomal DNA products from the 3 canine genotype isolates from seals produced mixed sequences at could not be evaluated.
Many animal societies have dominance hierarchies in which social rank is correlated with size. In such societies, the growth and size of individuals can be a strategic response to their social environment: in fishes, individuals may decrease their growth rate to remain small and retain a subordinate position; in mammals, individuals may increase their growth rate to become large and attain a dominant position—a strategy called competitive growth. Here, we investigate whether the clown anemonefish, Amphiprion percula , exhibits competitive growth also. We show that juvenile clownfish paired with a size-matched reproductive rival increase their growth rate and size relative to solitary controls. Remarkably, paired individuals achieved this, despite being provided with the same amount of food as solitary controls. Our results demonstrate that clownfish are able to increase their growth rate in response to social competition. This study adds to the growing body of evidence that the growth of social vertebrates can be a fine-tuned plastic response to their social environment.
Abstract. The purpose of the current study was to compare the molecular detection rate of Lawsonia intracellularis between feces and rectal swabs collected from 42 foals with suspected equine proliferative enteropathy (EPE). Fecal samples and rectal swabs were processed for DNA purification by using an automated extraction system. The purified DNA was then analyzed by real-time polymerase chain reaction (PCR) for the presence of the aspartate ammonia lyase (aspA) gene of L. intracellularis. Absolute quantitation was calculated by using a standard curve for L. intracellularis and expressed as copy numbers of the aspA gene of L. intracellularis per microliter of purified DNA. The combined PCR detection rate for L. intracellularis was 90%, with 38 foals testing PCR positive in feces (33 samples), rectal swabs (32), or both (27). Six foals tested PCR positive only in feces, whereas 5 tested positive only in rectal swabs. Feces yielded a significantly higher aspA gene copy number of L. intracellularis than rectal swabs. Feces and rectal swabs tested PCR negative from 4 foals. In conclusion, the results showed that feces yielded similar numbers of PCR-positive results, with a higher L. intracellularis aspA gene load than rectal swabs. By analyzing dual samples, the PCR detection rate for L. intracellularis increased from 76% and 79% for rectal swabs and feces, respectively, to 90%. Rectal swabs should be considered as an alternative sample type for EPE-suspected patients with decreased or no fecal output.Key words: Equine proliferative enteropathy; feces; horses; Lawsonia intracellularis; real-time polymerase chain reaction; rectal swab.Equine proliferative enteropathy (EPE) is a disease of foals caused by the obligate intracellular organism Lawsonia intracellularis. This emerging disease affects weanling foals and causes fever, lethargy, peripheral edema, diarrhea, colic, and weight loss. 6 The antemortem diagnosis of EPE may be challenging and relies on the presence of hypoproteinemia, exclusion of common enteric diseases, thickening of segments of the small intestinal wall observed on abdominal ultrasonography, positive serology, and molecular detection of L. intracellularis in feces. 8 One must keep in mind that a positive serologic result may represent exposure to infection rather than disease. Although no commercially available serologic assay has yet been systematically evaluated for the equine species, serologic assays have proven useful for routine diagnosis of PE in horses when combined with clinical signs and molecular detection of L. intracellularis in feces. 7,14 Several polymerase chain reaction (PCR) assays have been developed for the detection of L. intracellularis in feces. The sensitivity and specificity of the PCR technique in fecal samples has been evaluated for pigs and showed variable sensitivity and consistently high specificity. 3,5,9,13 Sensitivity is affected by sample quality and the presence of inhibitory substances in feces. PCR appears to reliably demonstrate L. intracellularis in the fec...
Inshore-offshore migration occurs frequently in seahorse species, either because of prey opportunities or because they are driven by reproduction, and variations in water temperature may dramatically change migratory seahorse behavior and physiology. The present study investigated the behavioral and physiological responses of the lined seahorse Hippocampus erectus under thermal stress and evaluated the potential effects of different temperatures on its reproduction. The results showed that the thermal tolerance of the seahorses was time dependent. Acute thermal stress (30°C, 2–10 h) increased the basal metabolic rate (breathing rate) and the expression of stress response genes (Hsp genes) significantly and further stimulated seahorse appetite. Chronic thermal treatment (30°C, 4 weeks) led to a persistently higher basal metabolic rate, higher stress response gene expression and higher mortality rates, indicating that the seahorses could not acclimate to chronic thermal stress and might experience massive mortality rates due to excessively high basal metabolic rates and stress damage. Additionally, no significant negative effects on gonad development or reproductive endocrine regulation genes were observed in response to chronic thermal stress, suggesting that seahorse reproductive behavior could adapt to higher-temperature conditions during migration and within seahorse breeding grounds. In conclusion, this simulation experiment indicates that temperature variations during inshore-offshore migration have no effect on reproduction, but promote significantly high basal metabolic rates and stress responses. Therefore, we suggest that the observed high tolerance of seahorse reproduction is in line with the inshore-offshore reproductive migration pattern of lined seahorses.This article has an associated First Person interview with the first author of the paper.
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