Comparisons of reproductive function and fatty acid fillet quality between triploid and diploid farm Atlantic salmon (Salmo salar).

Triploidy could prevent escaped farm salmon breeding in the wild, while also improving nutrient quality within farmed fillets. Despite these potential advantages, triploid Atlantic salmon have not been widely used in aquaculture, and their reproductive function has yet to be fully evaluated. Here, we compare reproductive function and fillet composition between triploid and diploid farm salmon under standard aquaculture rearing conditions. We show that female triploids are sterile and do not develop gonads. By contrast, males produce large numbers of motile spermatozoa capable of fertilizing wild salmon eggs. However, compared with diploids, reproductive development and survival rates of eggs fertilized by triploid males were significantly reduced, with less than 1% of eggs sired by triploid males reaching late-eyed stages of development. Analyses of fillets showed that total lipid and fatty acid quantities were significantly lower in triploid than in diploid Atlantic salmon fillets. However, when fatty acids were normalized to total lipid content, triploid fillets had significantly higher relative levels of important omega-3 long-chain polyunsaturated fatty acids. Our results show that: (i) escaped triploid farm salmon are very unlikely to reproduce in the wild and (ii) if able to match diploid fillet lipid content, triploid farm salmon could achieve better fillet quality in terms of essential fatty acids.

On the challenges and opportunities facing fish biology: a discussion of five key knowledge gaps.

Many fish species face increasing challenges associated with climate change and overfishing. At the same time, aquaculture is becoming vital for food security. Gaining a deeper understanding of the basic biology of fish is therefore more important than ever. Here we synthesize and summarize key questions, opportunities and challenges in fish biology highlighted during a round-table discussion at the 50th Anniversary Symposium of The Fisheries Society of the British Isles, held at the University of Exeter, U.K., in July 2017. We identified several knowledge gaps but also key opportunities for fish biology to inform food security, for collective behaviour, evolutionary history and trait correlations to predict responses to environmental change and for novel analytical approaches to mine existing data sets. Overall, more integrative approaches through stronger collaborations across different fields are needed to advance our understanding of the basic biology of fish.

Adhesion mechanisms in European whitefish Coregonus lavaretus eggs: is this a survival mechanism for high-energy spawning grounds?

This study examined the potential biochemical and mechanical structures that may contribute to egg adhesion in European whitefish Coregonus lavaretus. Experiments showed that eggs from a population of C. lavaretus from Loch Eck remained non-adhesive in a solution chemically similar to ovarian fluid but became adhesive seconds after contact with water. Examination of the ultrastructure of the chorion showed that the morphology changed significantly after contact with water, with nodule-like protuberances attached to connective filaments on the surface present in water-hardened but not non-water hardened eggs. Biochemical analysis showed the presence of Chain A, RNase ZF-3e proteins in the chorion of water-hardened but not non-water hardened eggs. Histochemical staining of the chorion of C. lavaretus eggs showed that the externa, but not the interna, stained positively for the presence of glycoproteins. From these results, it was concluded that C. lavaretus from Loch Eck possess both anatomical and biochemical adhesive mechanisms that have been undocumented in this species so far.

Differences in the clinical presentation of Trisomy 21 with and without autism.

BACKGROUND: Autism occurs 10 times more often in children with Down syndrome than in the general population, but diagnosing co-occurring autism in Down syndrome with severe intellectual disability is challenging. The objective of this case-control study was to identify characteristics differentiating children with trisomy 21 with and without autism and to determine the extent to which severe cognitive impairment affects the measures of autism symptomatology. METHOD: Twenty children with trisomy 21 and autism (cases) were compared with children with trisomy 21 without autism (controls) matched on chronologic age, race and gender. Communication, cognitive and adaptive behaviour skills were assessed with standardized instruments. Medical history was reviewed and medical records were examined for early head growth. Scores on the diagnostic algorithm of the Autism Diagnostic Interview--Revised (ADI-R) were compared after adjusting for cognitive ability as measured by the Stanford-Binet (Fifth Edition) non-verbal change sensitive score. RESULTS: Cases performed significantly more poorly on all assessments. Mean case-control differences for matched pairs were all significant at P < 0.0001 for receptive and expressive language skills, cognitive skills and adaptive skills. Seven cases had a history of seizures compared with one control(P = 0.01). After adjusting for cognitive ability, the mean scores on the Reciprocal Social Interaction, Communication, and Restricted, Repetitive and Stereotyped Behaviours domains of the ADI-R diagnostic algorithm remained significantly higher in cases compared with controls (P < 0.0001). All participants had decreased head size consistent with Down syndrome, with no case-control differences. CONCLUSION: Children with trisomy 21 and autism have significantly more impaired brain function than children with trisomy 21 without autism. However, the deficits in the core domains of social reciprocity and communication, and the restricted and repetitive interests are not entirely explained by the more severe cognitive impairment. This autism phenotype in children with trisomy 21 which includes an increased risk for seizures may indicate a widespread loss of functional connectivity in the brain.

Streptococcal myositis: a lesson.

Streptococcal myositis is a rare, often fatal, acute infection of the muscle, caused by an invasive group A beta-haemolytic streptococcus. It is characterised by muscle necrosis without abscess formation, and, in contrast to necrotising fasciitis, does not primarily affect the subcutaneous tissue or skin. A young adult male presented with streptococcal myositis initially affecting the rectus femoris muscle of his left thigh. The symptoms, signs and management are discussed. Particular emphasis is given to the benefits of emergency CT scans to diagnose and delineate the extent of the disease. These scans may need to be repeated if the disease progresses. The four cornerstones of management are: early diagnosis using emergency CT scans; high-dose intravenous antibiotics; early aggressive surgical debridement; and intensive fluid and nutritional support. Published by Elsevier Science Ltd. All rights reserved.

Postoperative infection following clean facial surgery.

Postoperative facial wound infection and breakdown adds to patient morbidity and compromises the cosmetic outcome. This prospective study of 351 patients with a total of 464 wounds for clean elective facial surgery assessed three significant risk factors for wound infection: operative site, oncological surgery, and complex surgery. The findings demonstrated a significantly higher infection rate for the nasal and auricular zones compared with the rest of the face. Wound infection rates were 6.5% for the nasal area, 5% for the auricular area, and 1.5% for the rest of the face. The higher risk of infection to these zones was found to be independent of the lesion excised (benign vs. malignant) and the complexity of the surgery performed. Oncological surgery (skin cancer) and complex surgery (skin grafts and local flaps) were found to increase the risk of postoperative infection significantly by up to fifteenfold compared with nononcological operations with direct closure. The associated morbidity and compromised cosmetic results with facial surgical wound breakdown makes it important to identify these higher risk factors and consider added prophylaxis.

Ilioinguinal block dissection for malignant melanoma.

A retrospective analysis of 41 patients treated for metastatic inguinal lymph node malignant melanoma is presented: 16 underwent inguinal node excision and 25 ilioinguinal node excision. The two groups were well matched for age, sex and other characteristics. The mean time in hospital (inguinal 20 days, ilioinguinal 18 days) and the complication rates (inguinal, ten of 16 patients, ilioinguinal, 13 of 25) were similar in each group. The incidence of groin relapse, defined as the development of symptomatic melanoma in the region of the inguinal or iliac node basins following block dissection, was lower after ilioinguinal block dissection (inguinal, three patients; ilioinguinal, none). Histological examination demonstrated a high proportion of iliac node involvement (13 of 25 patients), even in those with a single mobile inguinal lymph node clinically and no clinical or computed tomographic evidence of iliac node involvement. This supports the value of ilioinguinal block dissection and suggests that the associated morbidity need not be greater than that associated with inguinal clearance alone.

Capture and penetration processes of the free-living juveniles of Trichostrongylus colubriformis (Nematoda) by the nematophagous fungus, Arthrobotrys oligospora.

The nematode-trapping fungus Arthrobotrys oligospora traps and invades all the free-living juvenile stages of the trichostrongyle nematode Trichostrongylus colubriformis. The processes of capture and invasion of the 1st-stage juveniles are described using differential interference contrast optics and 3-D reconstruction techniques. The adhesive responsible for capture is well preserved using a freeze-substitution technique for scanning electron microscopy. The invasion process of the ensheathed 3rd-stage juvenile of T. colubriformis takes much longer than in the 1st- or 2nd-stage juvenile and involves the formation of secondary infection pegs between the sheath and the cuticle which appear to penetrate the cuticle by physical pressure.

Carbohydrate/lectin interactions between the nematophagous fungus, Arthrobotrys oligospora, and the infective juveniles of Trichostrongylus colubriformis (Nematoda).

Removal of the sheath of the ensheathed infective juvenile of Trichostrongylus colubriformis prevents capture by the nematophagous fungus Arthrobotrys oligospora. Exposure of the trap hyphae to a variety of saccharides, which may block a recognition system based on lectin/carbohydrate binding, failed to prevent capture but some saccharides did inhibit penetration and invasion by the fungus. Capture and penetration thus appear to be two distinct processes with capture being less specific than penetration. Carbohydrate residues were absent from the outer surface of the cuticle and the sheath but were present on the inner surface of the sheath. The limited accessibility of these lectin-binding sites may explain the slow process of infection of the infective juvenile by the fungus. The sheath does not protect the infective juvenile against attack by this nematophagous fungus.

Preparation of the nematode-trapping fungus, Arthrobotrys oligospora, for scanning electron microscopy by freeze substitution.

A freeze-substitution technique for preparing fungal specimens for scanning electron microscopy is described. This involves cryofixation in liquid nitrogen, freeze substitution in methanol at -20 degrees C and critical-point drying. The trapping complexes and conidiophores of the nematophagous fungus Arthrobotrys oligospora are well preserved and retain their normal three-dimensional arrangement.

Devil's-claw (Proboscidea louisianica), essential oil and its components : Potential allelochemical agents on cotton and wheat.

The potential allelopathic activity of devil's-claw [Proboscidea louisianica (Mill.) Thellung] essential oil and a few of the compounds it contains on the elongation of cotton (Gossypium hirsutum L.) and wheat (Triticum aestivum L.) radicles was studied using a Petri dish bioassay. Essential oil was collected by steam distillation using an all-glass-Teflon assembly. Ether extracts of the steam distillates from fresh devil's-claw were inhibitory to cotton and wheat radicle elongation. The following six components of devil's-claw essential oil identified by CGC-MS-DS were inhibitory to cotton and/or wheat at a concentration of 1 mM: vanillin, piperitenone, δ-cadinene,p-cymen-9-ol, α-bisabolol, and phenethyl alcohol.

Raising the radial artery forearm flap: the superficial ulnar artery "trap".

An anomalous superficial ulnar artery was encountered during the raising of a free radial artery forearm flap. A description is given of the anatomy of the ulnar artery, its variation and vulnerability during the raising of a forearm flap.