Browsing by Author "Fermin LM"

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An assessment of the accuracy of morphological techniques for identifying Lucilia cuprina and Lucilia sericata (Diptera: Calliphoridae)
(Taylor and Francis Group on behalf of the New Zealand Veterinary Association, 2025-10-13) Brett PTJ; Lawrence KE; Kenyon PR; Gedye K; Fermin LM; Pomroy W
Aims: To assess the accuracy of the morphological identification of Lucilia cuprina and Lucilia sericata by using molecular analysis as a reference standard test, and to describe the seasonality of these species. Methods: A convenience sample of L. cuprina and L. sericata flies was caught on eight farms from across New Zealand and stored at room temperature in 70% alcohol. They were first morphologically identified using published keys and then molecularly identified using primers to amplify the 28S rRNA region of the nuclear genome. The accuracy of the morphological identification was then estimated for each species using the molecular identification as a reference standard test. The correctness of the published keys was also tested by re-examining a sample of misidentified flies using enhanced magnification and photography. Results: The accuracy of the morphological identification for L. cuprina was 0.66 (95% CI = 0.58–0.73) and for L. sericata was 0.7 (95% CI = 0.62–0.77). There was no evidence for a difference in accuracy between species (p = 0.56), and re-examination of the misidentified flies found no faults in the published keys. The study confirmed that L. cuprina has a longer season of activity than L. sericata. Conclusions: These results emphasise the need to use molecular methods to confirm the identification of these species, especially when dealing with large, stored collections, rather than to rely on morphological identification alone. Clinical relevance: Without accurate fly identification and knowledge of insecticide resistance status, effective control and prevention of flystrike in New Zealand could be handicapped.
Controlled Cytoplast Arrest and Morula Aggregation Enhance Development, Cryoresilience, and In Vivo Survival of Cloned Sheep Embryos
(Mary Ann Liebert, Inc, 2021-02-02) McLean ZL; Appleby SJ; Fermin LM; Henderson HV; Wei J; Wells DN; Oback B
Zona-free somatic cell transfer (SCT) and embryo aggregation increase throughput and efficiency of cloned embryo and offspring production, respectively, but both approaches have not been widely adopted. Cloning efficiency is further improved by cell cycle coordination between the interphase donor cell and metaphase-arrested recipient cytoplast. This commonly involves inclusion of caffeine and omission of calcium to maintain high mitotic cyclin-dependent kinase activity and low calcium levels, respectively, in the nonactivated cytoplast. The aim of our study was to integrate these various methodological improvements into a single work stream that increases sheep cloning success. We show that omitting calcium during zona-free SCT improved blastocyst development from 6% to 13%, while caffeine treatment reduced spontaneous oocyte activation from 17% to 8%. In a retrospective analysis, morula aggregation produced high morphological quality blastocysts with better in vivo survival to term than nonaggregated controls (15% vs. 9%), particularly after vitrification (14% vs. 0%). By combining cytoplast cell cycle control with zona-free embryo reconstruction and aggregation, this novel SCT protocol maximizes the benefits of vitrification by producing more cryoresilient blastocysts. The presented cloning methodology is relatively easy to operate and further increases throughput and efficiency of cloned embryo and offspring production. Integration of additional reprogramming steps or alternate donor cells is straightforward, providing a flexible workflow that can be adapted to changing experimental requirements.
Morula complementation restores male germline in NANOS2 null sheep
(Oxford University Press on behalf of National Academy of Sciences, 2025-07-02) McLean ZL; Fermin LM; Appleby SJ; Wei J; Meng F; Maclean PH; Perry BJ; Brophy B; Turner P; Forrester-Gauntlett B; Wells DN; Snell RG; Oback B
Current livestock breeding is slow to respond to rapidly mounting environmental pressures that threaten sustainable animal protein production. New approaches can accelerate genetic improvement by multiplying valuable embryonic, rather than adult genotypes. Chimeras, derived from complementing a sterile host with a fertile donor embryo, provide a pathway to multiply and exclusively transmit elite male germlines. We established genetically sterile hosts and optimized embryo complementation conditions to achieve absolute germline transmission in sheep. The spermatogonia-specific gene NANOS2 was disrupted in male (NANOS2+/−, NANOS2−/−) and female (NANOS2−/−) ovine fetal fibroblasts via gRNA–Cas9-mediated homology-directed repair. Targeted cell strains and wild-type controls were used to produce cloned offspring for breeding and phenotyping. Male homozygous knockout clones lacked detectable germ cells, while the somatic compartment of the testis remained intact. By contrast, male monoallelic and female biallelic targeting of NANOS2 did not affect germline development, resulting in fertile animals capable of producing fertile offspring with normal reproductive performance. The germ cell niche in NANOS2−/− hosts was most efficiently complemented by aggregating compacted morulae, rather than earlier cleavage stages, resulting in 97% blastocyst chimerization. Embryo-complemented cloned lambs from two different donor cell lines showed variable chimerism across tissues from each germ layer, including various degrees of germline colonization. A subset of germline chimeras contained normal numbers of prospermatogonia, indicating that the germline was fully restored for absolute transmission of the donor cell genotype.
Smooth muscle hamartoma in a castrated male red deer (Cervus elaphus) in New Zealand.
(Taylor and Francis Group, 2023-07-01) Johnson SG; Fermin LM; Aberdein D; Lawrence KE
Reports of neoplasia in deer remain rare (Hill and Staples Citation1999), despite the conviction that as deer farming became more common, a greater number of pathological processes, including tumours, would be recognised in deer (Pérez et al. Citation1998). Skin tumours are among the most common neoplasms reported in red deer (Cervus elaphus) and are usually papillomavirus-associated dermal fibropapillomas and papillomas (Erdélyi et al. Citation2009; Vaatstra et al. Citation2014; Garcês et al. Citation2020). Additional reports of cutaneous and subcutaneous tumours in red deer include malignant schwannoma and dermal malignant melanoma (Pérez et al. Citation1998; Scandrett and Wobeser Citation2004). In related deer species, subcutaneous dermoid cysts have been described in caribou (Rangifer tarandus) (Wobeser et al. Citation2009) and cutaneous fibromas in predominantly male white-tailed deer (Odocoileus virginianus) (Berry Citation1925; Friend Citation1967; Sundberg and Nielsen Citation1982).
Theileria orientalis Ikeda infection detected in red deer but not dogs or horses in New Zealand.
(2024-09-02) Lawrence KE; Gedye K; Carvalho L; Wang B; Fermin LM; Pomroy WE
AIMS: To determine whether evidence for infection with Theileria orientalis (Ikeda) could be identified in samples of commercial red deer (Cervus elaphus), horses, and working farm dogs in New Zealand. METHODS: Blood samples were collected during October and November 2019 from a convenience sample of red deer (n = 57) at slaughter. Equine blood samples (n = 50) were convenience-sampled from those submitted to a veterinary pathology laboratory for routine testing in January 2020. Blood samples, collected for a previous study from a convenience sample of Huntaway dogs (n = 115) from rural regions throughout the North and South Islands of New Zealand between August 2018 and December 2020, were also tested. DNA was extracted and quantitative PCR was used to detect the T. orientalis Ikeda major piroplasm surface protein (MPSP) gene. A standard curve of five serial 10-fold dilutions of a plasmid carrying a fragment of the T. orientalis MPSP gene was used to quantify the number of T. orientalis organisms in the samples. MPSP amplicons obtained by end-point PCR on positive samples were isolated and subjected to DNA sequencing. The resulting sequences were compared to previously published T. orientalis sequences. RESULTS: There were 6/57 (10%) samples positive for T. orientalis Ikeda from the deer and no samples positive for T. orientalis Ikeda from the working dogs or horses. The mean infection intensity for the six PCR-positive deer was 5.1 (min 2.2, max 12.4) T. orientalis Ikeda organisms/µL. CONCLUSIONS AND CLINICAL RELEVANCE: Red deer can potentially sustain low infection intensities of T. orientalis Ikeda and could act as reservoirs of infected ticks. Further studies are needed to determine whether naïve ticks feeding on infected red deer can themselves become infected. ABBREVIATIONS: Cq: Quantification cycle; LOQ: Limits of quantification; MPSP: Major piroplasm surface protein; qPCR: Quantitative polymerase chain reaction.