Outbreaks of severe myositis in cultured white sturgeon (Acipenser transmontanus L.) associated with Streptococcus iniae

Outbreaks of an infectious disease affecting cultured white sturgeon (Acipenser transmontanus) were investigated. Clinical signs included erratic swimming, arching of the back and mortality. Necropsy findings included poorly demarcated yellow to dark-red and friable lesions in the epaxial muscle, ulcerative skin lesions and haemorrhages in the swim bladder and coelomic wall. Histological evaluation revealed areas of necrotizing and heterophilic myositis with aggregates of bacterial cocci. The lumen of blood vessels in the dermis, under ulcerated areas, and in the posterior kidney, was occluded by fibrin thrombi. Aggregates of Gram-positive cocci were observed in the muscle lesions and within the fibrin thrombi in the dermis and kidney. Genetically homogeneous Streptococcus iniae strains were recovered from affected fish from different outbreaks. The isolates shared high degree of similarity at gene locus (gyrB) with previously characterized S. iniae from cultured fish in California, confirming the emergence of this particular strain of S. iniae in US aquaculture.     

Simultaneous effect of sex and dose on efficacy of clove oil,tricaine methanesulfonate, 2‐phenoxyethanol and propofol as anaesthetics in guppies,Poecilia reticulata (Peters)

We studied the simultaneous effect of sex and dose on anaesthesia efficacy to estimate, if possible, the lowest effective dose (LED) for clove oil, tricaine methanesulphonate (MS‐222), 2‐phenoxyethanol (2‐PE) and propofol in mature guppies. LED is the lowest dose needed to reach A5 stage in a mean time of 3 min, with mean recovery (R5) time of 5 min. We used four doses/anaesthetic: 25, 50, 75 and 100 mg/L for clove oil; 120,140,160 and 180 mg/L for MS‐222; 800, 1,000, 1,200 and 1,400 mg/L for 2‐PE, and 7.50, 8.25, 10.00 and 11.25 mg/L for propofol. Each dose was tested on 10 females and 10 males. Morbidity, mortality and behavioural changes were checked on two control groups (10 males and 10 females/group). Sedation (A3), A5 and R5 times were recorded. Significant interactive effect dose*sex on A5 time was found for each anaesthetic agent (p_dose*sex < .05). Except for MS‐222 (p_dose*sex = .284), significant interactive effect dose * sex on R5 time was found (p_dose*sex < .05). A5 time in females tended to be greater than in males, but, in general, R5 times were longer in males. Body size differences between males and females could explain these differences in MS‐222 on A5 time and for clove oil, 2‐PE and propofol on R5 time. No dose simultaneous meet LED′s conditions relating to both A5 and R5 times; therefore the lowest doses inducing A5 in a mean time of 3 min could be a safe guideline for anaesthetic procedure in both male and females.     

Transduction and Transplantation of Spermatogonia into the Testis of Ram Lambs through the Extra-testicular Rete

Spermatogonial transplantation will provide a new way to study spermatogenesis in domestic animals, disseminate male genetics and produce transgenic animals, if efficiency can be improved. We evaluated a 'surgical' method for transplanting donor cells into testes of ram lambs, where the head of the epididymis is reflected, and a catheter introduced into the extra-testicular rete testis. We also tested transduction of ram spermatogonia with a lentiviral (LV) vector as a means to identify permanent colonization, and introduce genes into donor cells. Eight ram lambs, 11- to 13-week olds, were the recipients: in five, spermatogonia were injected into one testis, and the contralateral testis was an un-manipulated control: in two, spermatogonia were injected into one testis and the contralateral was sham-injected: in one, both testes were injected. Six lambs received spermatogonia labelled with a cell-tracking dye and these were collected 1 or 2 weeks after transplantation; three lambs received spermatogonia transduced with a LV vector driving the expression of enhanced Green Fluorescence Protein and these were collected after 2 months. Donor cells were detected by immunohistochemistry in tubules of seven of nine recipient testes. Approximately 22% of tubule cross-sections contained donor cells immediately after transplantation, and 0.2% contained virally transduced cells 2 months after transplantation. The onset of spermatogenesis was delayed, and there were lesions in both injected and sham-injected testes. Despite the effects of the surgery, elongated spermatids were present in one recipient testis 2 months after surgery. The results suggest that, after modifying the surgical and transduction techniques, this approach will be a means to produce good colonization by donor spermatogonia in sheep testes.     

The fate of arsenic in soils adjacent to an old mine site (Bustarviejo,Spain): mobility and transfer to native flora

Background, aim, and scope  

The mobility of arsenic in soils and its transfer to other environmental components present significant environmental risks. The management of polluted land is determined by the availability, mobility, and transfer of inorganic pollutants to different ecosystem compartments. In this paper, the fate of arsenic at this mining site has been evaluated to determine future management practises to minimise such risk.     

In silico and gene expression analysis of the acute inflammatory response of gilthead seabream (Sparus aurata) after subcutaneous administration of carrageenin

Fish Physiology and Biochemistry - Inflammation is one of the main causes of loss of homeostasis at both the systemic and molecular levels. The aim of this study was to investigate in silico the...     

Sorption and thermodynamic properties of buried juvenile <Emphasis Type="Italic">Pinus sylvestris</Emphasis> L. wood aged 1,170 ± 40 BP

The hygroscopicity and thermodynamic properties of buried juvenile Pinus sylvestris L. wood with an age of 1,170 ± 40 BP were compared with the corresponding values of juvenile wood of the same species from recently cut trees. The 35 and 50°C isotherms were plotted following the saturated salts method and subsequently fitted in accordance with the GAB model. The isotherms were then compared by means of the hysteresis coefficients. X-ray diffractograms were used to analyse the crystal structure of the cellulose. The effect of time on the buried wood caused hemicelluloses degradation and a decrease in the crystallinity index and the crystallite length, resulting in an increase in the proportion of amorphous zones. Because of this, the equilibrium moisture contents of the buried wood are higher than of the recent wood, both in adsorption and desorption. In terms of the thermodynamic properties, the heat involved is greater in the buried wood than in the recent wood.     

Does otolith macrostructure record environmental or biological events? The case of black hake (Merluccius polli and Merluccius senegalensis)

Fish age determination using otoliths requires a prior understanding of growth mark deposition patterns (translucent rings, TR) as well as their connection with internal or external events experienced by the fish. This study analysed the macrostructural seasonal ring deposition pattern observed in transversal sections of black hake otoliths. A total of 793 black hake otoliths were collected in autumn and spring 2007 from research and commercial surveys carried out in continental and shelf waters off Mauritania. Most of the Merluccius polli otoliths presented narrow and wide translucent rings (NTR and WTR, respectively) regardless of fish size, whereas Merluccius senegalensis otoliths only showed NTR. This seemed to be a sign of ontogenetic discrepancy between the two black hake species, whose otoliths confirmed the existence of significant differences in their growth patterns.The frequency distributions of the number of TR counted along the ventral radius (VR) of the otolith from the nucleus (birth date) and from the ventral edge (death date) were analysed to ascertain whether a specific endogenous event (Hypothesis A) or a precise environmental event (Hypothesis B) could restrain growth leading to the formation of TR. The general TR frequency distribution pattern was somewhat similar for both hake species, which showed marked TR at comparable distances. Within each species, TR frequency distributions of their distances from the nucleus along the otolith VR were quite similar between sexes, seasons, and fish sizes. Our results support the idea of a coincident biological event, such as first maturity, slowing down the growth process and thus provoking the formation of TR in otoliths of both species.This study also experience difficulty using the complex and highly variable macrostructural pattern of black hake otoliths to establish age interpretation criteria for these two species.