Studies of embryo transfer from cattle clinically affected by bovine spongiform encephalopathy (BSE)

Semen from 13 bulls, eight with clinical bovine spongiform encephalopathy (BSE), was used to artificially inseminate (AI) 167 cows with clinical BSE, and their resultant embryos were collected non-surgically seven days after AI. The viable and non-viable embryos with intact zonae pellucidae were washed 10 times (as recommended by the International Embryo Transfer Society) then frozen. Later, 587 of the viable embryos were transferred singly into 347 recipient heifers imported from New Zealand, and 266 live offspring were born of which 54.1 per cent had a BSE-positive sire and a BSE-positive dam. The recipients were monitored for clinical signs of BSE for seven years after the transfer, and the offspring were monitored for seven years after birth. Twenty-seven of the recipients and 20 offspring died while being monitored but none showed signs of BSE. Their brains, and the brains of the recipients and offspring killed after seven years, were examined for BSE by histopathology, PrP immunohistochemistry, and by electron microscopy for scrapie-associated fibrils. They were all negative. In addition, 1020 non-viable embryos were sonicated and injected intracerebrally into susceptible mice (20 embryos per mouse) which were monitored for up to 700 days, after which their brains were examined for spongiform lesions. They were all negative. It is concluded that embryos are unlikely to carry BSE infectivity even if they have been collected at the end-stage of the disease, when the risk of maternal transmission is believed to be highest.     

The effect of fresh seaweed and a formulated diet supplemented with seaweed on the growth and gonad quality of the collector sea urchin,Tripneustes gratilla,under farm conditions

This gonad enhancement study investigates the effect of different fresh and formulated feeds and feeding regimes on the growth and gonad quality of wild‐collected adult sea urchin, Tripneustes gratilla, under farm conditions for over 18 weeks. In the first 12 weeks (phase 1), urchins were fed fresh Ulva rigida (U); a 50:50 mixture of fresh U. rigida and Gracilaria gracilis (UG); fresh G. gracilis (G) and a formulated diet 20U (containing 20% U. rigida), and in the final 6 weeks (phase 2) of the study, diet was changed to a formulated feed (20U diet). By the end of phase 1, urchins fed the 20U diet produced gonads (50.72 ± 5.4 g) that were significantly heavier (p < .001) than the gonads of urchins fed the fresh seaweed diets (U, UG & G). By the end of phase 2, gonad weight of urchins in treatment groups UG‐20U and G‐20U were similar to those fed the 20U‐20U diet. Gonad colour of urchins in the G‐20U treatment became significantly lighter (ANOVA, p = .029) and poorer quality, compared with urchins in the U‐20U group. This gonad enhancement study, conducted on wild‐collected adult T. gratilla, has shown that a formulated feed (20U diet) can enhance gonad growth and produce commercially acceptable gonads. This farm‐based study supports previous findings from aquarium‐based studies by our group and indicates that short‐term sea urchin gonad enhancement can be carried out under farm conditions in South Africa.     

Evaluation of visible implant elastomer tags for pathogenesis research in Nile tilapia (Oreochromis niloticus)

Two different colours (red and green) of visible implant elastomer (VIE) were used in Nile tilapia (Oreochromis niloticus). The visibility, location and retention of the VIE tags was investigated and any adverse effects on fish survival and growth determined. The use of VIE tags for monitoring individual fish during a bacterial challenge with either Streptococcus agalactiae or S. iniae was also studied. The results showed that VIE treated fish were lighter but not shorter than the non‐tagged control fish and that tagging caused no mortality. The retention of tags was better at the base of pectoral fin followed by the nasal area, lower abdomen, upper abdomen and branchiostegal rays inside the operculum. During the bacterial challenge experiment individual animals could be easily identified using the VIE tags. In this preliminary study, VIE tagging appears suitable for Nile tilapia research, as with other fish species, and could be a novel method to identify individual animals during microbial pathogenesis studies.     

Biallelic inactivation of BRCA2 in Fanconi anemia

Fanconi anemia (FA) is a rare autosomal recessive cancer susceptibility disorder characterized by cellular hypersensitivity to mitomycin C (MMC). Six FA genes have been cloned, but the gene or genes corresponding to FA subtypes B and D1 remain unidentified. Here we show that cell lines derived from FA-B and FA-D1 patients have biallelic mutations in BRCA2 and express truncated BRCA2 proteins. Functional complementation of FA-D1 fibroblasts with wild-type BRCA2 complementary DNA restores MMC resistance. Our results link the six cloned FA genes with BRCA1 and BRCA2 in a common pathway. Germ-line mutation of genes in this pathway may result in cancer risks similar to those observed in families with BRCA1 or BRCA2 mutations.     

Atlantic salmon in a rapidly changing environment—Facing the challenges of reduced marine survival and climate change

1. Atlantic salmon populations have declined in recent decades. Many of the threats to the species during its freshwater and coastal residency periods are known, and management approaches are available to mitigate them. The global scale of climate change and altered ocean ecosystems make these threats more difficult to address.
2. Managers need to be aware that promoting strong, healthy, and resilient wild populations migrating from rivers is the optimal approach currently to reduce the impacts of changing ecosystems and low marine survival. We argue that a fundamental strategy should be to ensure that the highest number of wild smolts in the best condition leave from rivers and coastal areas to the ocean. There is great scope for water quality, river regulation, migration barriers, and physical river habitat improvements.
3. Maintenance of genetic integrity and diversity of wild populations by eliminating interbreeding with escaped farmed salmon, eliminating poorly planned stocking, and reducing impacts that reduce population sizes to dangerously low levels will support the ability of Atlantic salmon to adapt to changing environments. Reducing the impacts from aquaculture and other human activities in coastal areas can greatly increase marine survival in affected areas.
4. As most of the threats to wild salmon are the result of human activities, a focus on human dimensions and improved communication, from scientific and management perspectives, needs to be increasingly emphasized. When political and social will are coupled with adequate resources, managers often have the tools to mitigate many of the threats to wild salmon.

     

Three‐dimensional conformal radiation therapy alone or in combination with surgery for treatment of canine intracranial meningiomas

Treatment protocols, treatment planning methods and tumour types in studies evaluating radiotherapy for canine brain tumours have been varied. This case series retrospectively evaluated the outcome of definitive, three‐dimensional conformal radiation therapy (3D‐CRT) as either a sole modality or as an adjuvant to surgery in 31 dogs diagnosed with meningioma by histopathology (n = 10) or cross‐sectional imaging of the head (n = 21, assessed independently by two board certified radiologists). Prescribed dose ranged from 45 to 54 Gy in 2.5 to 3 Gy fractions. Median overall survival was 577 days (interquartile range = 272–829 days; range = 30–1942 days) when all deaths were considered and 906 days (interquartile range = 336–912 days; range = 101–1942 days) when only dogs dying due to meningioma were considered. No significant difference in survival time was detected for the defined clinical or imaging findings or between treatment with radiotherapy alone versus adjuvant radiotherapy, suggesting that 3D‐CRT may be a viable alternative to surgery.     

Hypofractionated radiation therapy of oral melanoma in five cats

Five cats with melanoma involving the oral cavity were treated with hypofractionated radiation therapy (RT). Cobalt photons were used to administer three fractions of 8.0 Gray (Gy) for a total dose of 24 Gy. Four cats received radiation on days 0, 7, and 21 and one cat received radiation on days 0, 7, and 13. One of the cats received additional irradiation following the initial treatment course. Two cats received chemotherapy. Their age ranged from 11 to 15 years with a median age of 12 years. Three cats had a response to radiation, including one complete response and two partial responses. All five cats were euthanized due to progression of disease, with one cat having evidence of metastatic disease at the time of euthanasia. The median survival time for the five cats was 146 days (range 66-224 days) from the start of RT. The results of this study suggest that oral melanoma in cats may be responsive to hypofractionated RT, but response does not seem to be durable.     

Trading in waste: Integrating sustainable development goals and environmental policies in trade negotiations toward enhanced solid waste management in Pacific Islands countries and territories

This paper provides a broad survey of existing literature on contemporary solid waste management (SWM) in the Pacific region to underscore an urgent and compelling need for improved SWM. Despite advances in waste management systems and funding for technical support and capacity building from a range of sources, waste continues to threaten public and ecological health and the economy in Pacific Islands Countries and Territories (PICTs). SWM in the Pacific requires innovative thinking in a challenging environment of remoteness, limited available land, fragile ecosystems, vulnerability to natural hazards and subsequent climate sensitivity. Many PICTs are under considerable pressure to open their markets up to trade liberalisation. Increasing links to the global economy through trade liberalisation could either further exacerbate waste management challenges in the Pacific or contribute to environmental protection and sustainable development goals. The authors argue that if the PICTs' urgent waste management challenges are to be meaningfully addressed, the region's leaders must ensure trading partners conform to local environmental protection policies and that trade agreements align with sustainable development goals.