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Di-n-butyl phthalate (DBP) is widely used as a plasticizer in personal care and medical products and is known to induce toxicity in the male reproductive organs in both mammals and birds. In this study, there was investigation of the effects of DBP on the epithelium of the rete testis, proximal, and distal efferent ductules and epididymal duct of adult Japanese quail (Coturnix japonica) following treatment with varying doses during the pre-pubertal and peri-pubertal periods. Pre-pubertal quail (n = 25) 4 weeks post-hatching were dosed orally with 10, 50, 200 and 400 mg DBP/kg/d, for 30 days and control birds were administered corn-oil only (n = 5 per group). Histo-metrically, there was lesser (P < 0.001) epithelial heights of the rete testis and efferent ductules in all quail DBP-treated groups, but not in the epididymal duct epithelium. There were no morphological change effects as a result of DBP treatments in the rete testis epithelium, while there were epithelial cytoplasmic vacuoles detected in the distal efferent ductule and epididymal duct of birds treated with 50, 200 and 400 mg DPB/kg/d. There were several lesions, including degenerative changes, cytoplasmic vacuoles, apoptosis and autophagy in the epithelium of the proximal efferent ductule in quail treated with 200 and 400 mg DBP/kg/d. Overall, the results indicate that treatment with DBP during the pre-pubertal period induced dose-dependent histometric and morphological changes in the epithelium of the epididymal region. It is concluded that the proximal efferent ductule was a highly sensitive component of the epididymal tissues of Japanese quail following treatment with DBP during the pre-pubertal period.
Mohammed I.A. Ibrahim; June Williams; Christo J. Botha. Dose-related morphological changes in the epididymal region of sexually active adult male Japanese quail treated with di-n-butyl phthalate (DBP) commencing during the pre-pubertal stage. Animal Reproduction Science 2021, 227, 106733 .
AMA StyleMohammed I.A. Ibrahim, June Williams, Christo J. Botha. Dose-related morphological changes in the epididymal region of sexually active adult male Japanese quail treated with di-n-butyl phthalate (DBP) commencing during the pre-pubertal stage. Animal Reproduction Science. 2021; 227 ():106733.
Chicago/Turabian StyleMohammed I.A. Ibrahim; June Williams; Christo J. Botha. 2021. "Dose-related morphological changes in the epididymal region of sexually active adult male Japanese quail treated with di-n-butyl phthalate (DBP) commencing during the pre-pubertal stage." Animal Reproduction Science 227, no. : 106733.
Antibiotic resistance has been reported since the 1940s in both human and veterinary medicine. Many years of monitoring milk samples in South Africa led to identification of a novel maltose-negative Staphylococcus aureus (S. aureus) strain, which appears to be an emerging pathogen. In this study, the susceptibility of this strain to antibiotics was evaluated over time, during diverse seasons in various provinces and according to somatic cell count (SCC) categories. A data set of 271 maltose-negative S. aureus isolates, from milk samples of 117 dairy herds, was examined using the disk diffusion method, between 2010 and 2017. This study also compared the susceptibility testing of 57 maltose-negative and 57 maltose-positive S. aureus isolated from 38 farms, from three provinces using minimum inhibitory concentration (MIC). The MIC results for the maltose-negative S. aureus isolates showed highest resistance to ampicillin (100%) and penicillin (47.4) and lowest resistance (1.8%) to azithromycin, ciprofloxacin and erythromycin. The maltose-negative S. aureus isolates showed overall significantly increased antibiotic resistance compared to the maltose-positive strains, as well as multidrug resistance. Producers and veterinarians should consider probability of cure of such organisms (seemingly non-chronic) when adapting management and treatment, preventing unnecessary culling.
Joanne Karzis; Inge-Marié Petzer; Edward F. Donkin; Vinny Naidoo; Eric M.C. Etter. Surveillance of Antibiotic Resistance of Maltose-Negative Staphylococcus aureus in South African Dairy Herds. Antibiotics 2020, 9, 616 .
AMA StyleJoanne Karzis, Inge-Marié Petzer, Edward F. Donkin, Vinny Naidoo, Eric M.C. Etter. Surveillance of Antibiotic Resistance of Maltose-Negative Staphylococcus aureus in South African Dairy Herds. Antibiotics. 2020; 9 (9):616.
Chicago/Turabian StyleJoanne Karzis; Inge-Marié Petzer; Edward F. Donkin; Vinny Naidoo; Eric M.C. Etter. 2020. "Surveillance of Antibiotic Resistance of Maltose-Negative Staphylococcus aureus in South African Dairy Herds." Antibiotics 9, no. 9: 616.
Vermeersiekte or “vomiting disease” is an economically important disease of ruminants following ingestion of Geigeria (G.) species in South Africa. Sheep are more susceptible, and poisoning is characterized by stiffness, regurgitation, bloat, paresis, and paralysis. Various sesquiterpene lactones have been implicated as the cause of poisoning. The in vitro cytotoxicity of two sesquiterpene lactones, namely, ivalin (purified from Geigeria aspera) and parthenolide (a commercially available sesquiterpene lactone), were compared using mouse skeletal myoblast (C2C12) and rat embryonic cardiac myocyte (H9c2) cell lines, representing the oesophageal, skeletal and cardiac muscles, which are affected in sheep. For 24, 48, and 72 h, both cell lines were exposed. A colorimetric viability assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), was used to assess cytotoxicity. A concentration-dependent cytotoxic response was observed in both cell lines, however, the C2C12 cells were more sensitive, with the half-maximal effective concentrations (EC50s) ranging between 2.7 and 3.3 µM. In addition, the effect that ivalin and parthenolide has on desmin, an important cytoskeletal intermediate filament in myocytes, was evaluated using the C2C12 myoblasts. Disorganization and aggregation of desmin were caused by both sesquiterpene lactones, which could clarify some of the ultrastructural lesions described in vermeersiekte.
Christo J. Botha; Y. Zethu Mathe; Gezina C. H. Ferreira; E. Annette Venter. Cytotoxicity of the Sesquiterpene Lactones, Ivalin and Parthenolide in Murine Muscle Cell Lines and Their Effect on Desmin, a Cytoskeletal Intermediate Filament. Toxins 2020, 12, 459 .
AMA StyleChristo J. Botha, Y. Zethu Mathe, Gezina C. H. Ferreira, E. Annette Venter. Cytotoxicity of the Sesquiterpene Lactones, Ivalin and Parthenolide in Murine Muscle Cell Lines and Their Effect on Desmin, a Cytoskeletal Intermediate Filament. Toxins. 2020; 12 (7):459.
Chicago/Turabian StyleChristo J. Botha; Y. Zethu Mathe; Gezina C. H. Ferreira; E. Annette Venter. 2020. "Cytotoxicity of the Sesquiterpene Lactones, Ivalin and Parthenolide in Murine Muscle Cell Lines and Their Effect on Desmin, a Cytoskeletal Intermediate Filament." Toxins 12, no. 7: 459.
Diplodiosis is an important neuromycotoxicosis of ruminants in South Africa when grazing on harvested maize fields in winter. It is believed to be caused by mycotoxin(s) synthesised by Stenocarpella (Diplodia) maydis. Although several metabolites have been isolated from S. maydis culture material, none of these have been administered to ruminants to reproduce the disease. The objectives of this study were to isolate diplodiatoxin and to administer it to juvenile goats. Diplodiatoxin, considered as a major metabolite, was purified from S. maydis-infected maize cultures (Coligny 2007 isolate). Following intravenous administration of 2 mg and 4 mg diplodiatoxin/kg body weight for five consecutive days to two juvenile goats, no clinical signs reminiscent of diplodiosis were observed. Based on previous experimental results and if diplodiatoxin was the causative compound, the dosage regimen employed was seemingly appropriate to induce diplodiosis. In addition, intraruminal administration of 2 mg/kg diplodiatoxin to one goat for three consecutive days also did not induce clinical signs. It appears as if diplodiatoxin alone is not the causative compound. Other metabolites and/or mixtures of diplodiatoxin and other mycotoxins, when available in sufficient quantities, should also be evaluated.
Christo J. Botha; Louis G.J. Ackerman; Mxolisi G. Masango; Luke F. Arnot. Failure of diplodiatoxin to induce diplodiosis in juvenile goats. Onderstepoort Journal of Veterinary Research 2020, 87, e1 -e4.
AMA StyleChristo J. Botha, Louis G.J. Ackerman, Mxolisi G. Masango, Luke F. Arnot. Failure of diplodiatoxin to induce diplodiosis in juvenile goats. Onderstepoort Journal of Veterinary Research. 2020; 87 (1):e1-e4.
Chicago/Turabian StyleChristo J. Botha; Louis G.J. Ackerman; Mxolisi G. Masango; Luke F. Arnot. 2020. "Failure of diplodiatoxin to induce diplodiosis in juvenile goats." Onderstepoort Journal of Veterinary Research 87, no. 1: e1-e4.
Geigeria poisoning, referred to as 'vermeersiekte' is an important plant poisoning in southern Africa. Three sesquiterpene lactones, isogeigerin acetate (1) ivalin (2) and geigerin (3) were isolated and purified from Geigeria aspera Harv. (Asteraceae). Structures were deduced using 1 and 2D NMR spectroscopy and mass spectrometry, while the absolute configurations of compounds 1 and 3 were determined for the first time by X-ray crystal diffraction analyses. Cytotoxicity of isogeigerin acetate, ivalin and geigerin were compared by exposing a murine skeletal myoblast (C2C12) cell line to varying concentrations of the three sesquiterpene lactones isolated. Cell viability was assessed using the methyl-thiazolyl-tetrazolium (MTT) assay. The EC50s were 3.746, 0.0029 and 3.792 mM for isogeigerin acetate (1), ivalin (2) and geigerin (3), respectively. The results indicate that ivalin is much more toxic, approximately 1000 times, in vitro compared to isogeigerin acetate and geigerin.
Gerda Fouche; Louis G. J. Ackerman; E. Annette Venter; Y. Zethu Mathe; Dave C. Liles; Christo J. Botha. Sesquiterpene lactones from Geigeria aspera Harv. and their cytotoxicity. Natural Product Research 2019, 1 -7.
AMA StyleGerda Fouche, Louis G. J. Ackerman, E. Annette Venter, Y. Zethu Mathe, Dave C. Liles, Christo J. Botha. Sesquiterpene lactones from Geigeria aspera Harv. and their cytotoxicity. Natural Product Research. 2019; ():1-7.
Chicago/Turabian StyleGerda Fouche; Louis G. J. Ackerman; E. Annette Venter; Y. Zethu Mathe; Dave C. Liles; Christo J. Botha. 2019. "Sesquiterpene lactones from Geigeria aspera Harv. and their cytotoxicity." Natural Product Research , no. : 1-7.
Ingestion of large quantities of Geigeria species by sheep causes “vermeersiekte”, an economically important poisoning in southern Africa. The toxic principles are several sesquiterpene lactones, such as vermeerin, geigerin and ivalin. These sesquitepene lactones are myotoxic and the disease is characterized by microscopic and ultrastructural lesions in skeletal and cardiac muscle. Murine myoblast cells (C2C12) were exposed to 2.0, 2.5 and 5.0 mM geigerin for 24, 48 and 72 h to evaluate its effect on cytoskeletal proteins and filaments using immunocytochemistry and immunofluorescence staining. A concentration-dependent cytotoxic response was observed in desmin-expressing murine myoblasts under the light microscope, evidenced by disorganization and dot-like perinuclear aggregation of desmin filaments in the cells. β-Tubulin, other desmin-associated proteins (αB-crystallin and synemin) as well as the microfilament F-actin were unaffected. The disorganization and aggregation of desmin following exposure to increasing geigerin concentrations is significant and can explain some of the striated muscle lesions observed in “vermeersiekte”.
Christo J. Botha; E. Annette Venter; Gezina C.H. Ferreira; Rephima M. Phaswane; Sarah J. Clift. Geigerin-induced disorganization of desmin, an intermediate filament of the cytoskeleton, in a murine myoblast cell line (C2C12). Toxicon 2019, 167, 162 -167.
AMA StyleChristo J. Botha, E. Annette Venter, Gezina C.H. Ferreira, Rephima M. Phaswane, Sarah J. Clift. Geigerin-induced disorganization of desmin, an intermediate filament of the cytoskeleton, in a murine myoblast cell line (C2C12). Toxicon. 2019; 167 ():162-167.
Chicago/Turabian StyleChristo J. Botha; E. Annette Venter; Gezina C.H. Ferreira; Rephima M. Phaswane; Sarah J. Clift. 2019. "Geigerin-induced disorganization of desmin, an intermediate filament of the cytoskeleton, in a murine myoblast cell line (C2C12)." Toxicon 167, no. : 162-167.
Moraea pallida Bak. (yellow tulp) poisoning is the most important cardiac glycoside-induced intoxication in ruminants in South Africa. The toxic principle, 1α, 2α-epoxyscillirosidine, is a bufadienolide. To replace the use of sentient animals in toxicity testing, the aim of this study was to evaluate the cytotoxic effects of epoxyscillirosidine on rat embryonic cardiomyocytes (H9c2 cell line). This in vitro cell model can then be used in future toxin neutralization or toxico-therapy studies. Cell viability, evaluated with the methyl blue thiazol tetrazolium (MTT) assay, indicated a hormetic dose/concentration response, characterized by a biphasic low dose stimulation and high dose inhibition. Increased cell membrane permeability and leakage, as expected with necrotic cells, were demonstrated with the lactate dehydrogenase (LDH) assay. The LC50 was 382.68, 132.28 and 289.23 μM for 24, 48, and 72 h respectively. Numerous cytoplasmic vacuoles, karyolysis and damage to the cell membrane, indicative of necrosis, were observed at higher doses. Ultra-structural changes suggested that the cause of H9c2 cell death, subsequent to epoxyscillirosidine exposure, is necrosis, which is consistent with myocardial necrosis observed at necropsy. Based on the toxicity observed, and supported by ultra-structural findings, the H9c2 cell line could be a suitable in vitro model to evaluate epoxyscillirosidine neutralization or other therapeutic interventions in the future.
Hamza Ibrahim Isa; Gezina Catharina Helena Ferreira; Jan Ernst Crafford; Christoffel Jacobus Botha. Epoxyscillirosidine Induced Cytotoxicity and Ultrastructural Changes in a Rat Embryonic Cardiomyocyte (H9c2) Cell Line. Toxins 2019, 11, 284 .
AMA StyleHamza Ibrahim Isa, Gezina Catharina Helena Ferreira, Jan Ernst Crafford, Christoffel Jacobus Botha. Epoxyscillirosidine Induced Cytotoxicity and Ultrastructural Changes in a Rat Embryonic Cardiomyocyte (H9c2) Cell Line. Toxins. 2019; 11 (5):284.
Chicago/Turabian StyleHamza Ibrahim Isa; Gezina Catharina Helena Ferreira; Jan Ernst Crafford; Christoffel Jacobus Botha. 2019. "Epoxyscillirosidine Induced Cytotoxicity and Ultrastructural Changes in a Rat Embryonic Cardiomyocyte (H9c2) Cell Line." Toxins 11, no. 5: 284.
Intoxication by Moraea pallida Bak. (yellow tulp) in livestock is of great importance in South Africa, ranking top among all plant-induced cardiac glycoside toxicosis. The toxic principle, a bufadienolide, is 1α, 2α-epoxyscillirosidine. Treatment of poisoning is challenging and affected livestock often succumbs due to the stress of handling. Manipulating animals to resist poisoning is a potential management strategy. The goal of this study was to explore the potential to develop a vaccine against epoxyscillirosidine by raising antibodies against epoxyscillirosidine in sheep and to assess the neutralization ability of the antibodies in vitro. Epoxyscillirosidine was successfully conjugated to keyhole limpet haemocyanin (KLH) and bovine serum albumin (BSA) rendering them immunogenic. The sheep, vaccinated with epoxyscillirosidine-KLH conjugate (n = 4) and KLH (n = 2) with Montanide, developed antibodies as determined with an indirect enzyme linked immunosorbent assay (ELISA). Total immunoglobulins from sera of vaccinated and control sheep that were purified and concentrated using ammonium sulphate precipitation were 11,940 and 7850 μg, respectively. The in vitro neutralization assay using the methyl blue tetrazolium bromide (MTT) cell viability assay indicated no significant difference (p > 0.05) between anti-epoxyscillirosidine-KLH and KLH antibodies. Rather, the antibodies seemed to enhance the cytotoxicity of epoxyscillirosidine in H9c2 cells. Thus, it is necessary to develop improved vaccination methods to generate antibodies capable of neutralizing the functional group responsible for epoxyscillirosidine toxicity.
Hamza Ibrahim Isa; Gezina Catharina Helena Ferreira; Jan Crafford; Christoffel Jacobus Botha. Evaluation of in vitro neutralization of epoxyscillirosidine by antibodies raised in sheep. Toxicon 2019, 164, 20 -25.
AMA StyleHamza Ibrahim Isa, Gezina Catharina Helena Ferreira, Jan Crafford, Christoffel Jacobus Botha. Evaluation of in vitro neutralization of epoxyscillirosidine by antibodies raised in sheep. Toxicon. 2019; 164 ():20-25.
Chicago/Turabian StyleHamza Ibrahim Isa; Gezina Catharina Helena Ferreira; Jan Crafford; Christoffel Jacobus Botha. 2019. "Evaluation of in vitro neutralization of epoxyscillirosidine by antibodies raised in sheep." Toxicon 164, no. : 20-25.
Consumption of bufadienolide-containing plants are responsible for many livestock mortalities annually. Bufadienolides are divided into two groups; non-cumulative bufadienolides and cumulative bufadienolides. Cumulative bufadienolides are referred to as neurotoxic, as the chronic intoxication with this type of bufadienolide results in a paretic/paralytic syndrome known as ‘krimpsiekte’. The in vitro cytotoxicity of a non-cumulative bufadienolide, 1α,2α-epoxyscillirosidine, and a cumulative bufadienolide, lanceotoxin B, were compared using the MTT ((3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction) assay after exposing rat myocardial (H9c2) and mouse neuroblastoma (Neuro-2a) cell lines. The effect of these two bufadienolides on cell ultrastructure was also investigated using transmission electron microscopy (TEM). H9c2 cells exhibited greater cytotoxicity when exposed to 1α,2α-epoxyscillirosidine, compared to lanceotoxin B. In contrast, Neuro-2a cells were more susceptible to lanceotoxin B. The EC50 (half maximal effective concentration) of lanceotoxin B exposure of Neuro-2a cells for 24–72 h ranged from 4.4–5.5 µM compared to EC50s of 35.7–37.6 µM for 1α,2α-epoxyscillirosidine exposure of Neuro-2a cells over the same period. 1α,2α-Epoxyscillirosidine induced extensive vacuolization in both cell types, with swollen RER (rough endoplasmic reticulum) and perinuclear spaces. Lanceotoxin B caused swelling of the mitochondria and sequestration of cytoplasmic material within autophagic vesicles. These results corroborate the notion that cumulative bufadienolides are neurotoxic.
Danielle Henn; Annette Venter; Christo Botha. In Vitro Cytotoxicity Induced by the Bufadienolides 1α,2α-Epoxyscillirosidine and Lanceotoxin B on Rat Myocardial and Mouse Neuroblastoma Cell Lines. Toxins 2019, 11, 14 .
AMA StyleDanielle Henn, Annette Venter, Christo Botha. In Vitro Cytotoxicity Induced by the Bufadienolides 1α,2α-Epoxyscillirosidine and Lanceotoxin B on Rat Myocardial and Mouse Neuroblastoma Cell Lines. Toxins. 2019; 11 (1):14.
Chicago/Turabian StyleDanielle Henn; Annette Venter; Christo Botha. 2019. "In Vitro Cytotoxicity Induced by the Bufadienolides 1α,2α-Epoxyscillirosidine and Lanceotoxin B on Rat Myocardial and Mouse Neuroblastoma Cell Lines." Toxins 11, no. 1: 14.
There are no data available on the use of hand-held X-ray fluorescence (XRF) spectrometry to determine trace element concentrations in veterinary diagnostics. The hand-held XRF spectrometer is easy to use and does not require extensive training for the operator. In Sub-Saharan Africa with few centralised analytical laboratories equipped with expensive apparatus or mass spectrometry capabilities, trace element analysis using the hand-held XRF spectrometer provides an alternative. The objective of this study was to compare ovine hepatic copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), selenium (Se) and zinc (Zn) concentrations as obtained with the hand-held XRF spectrometer to those of a reference laboratory using inductively coupled plasma mass spectrometry (ICP-MS). Thirty ovine livers were obtained from an abattoir; prepared as wet blended and oven-dried samples and analysed. Bayesian correlation was used to assess the correspondence between results from the XRF and ICP-MS analyses. The oven-dried preparation procedure for XRF provided the best correlation with the ICP-MS data. The correlations for Cu and Zn were strong and the XRF method may represent a suitable substitute for ICP-MS analysis. For Mn and Fe the correlations were moderately strong and the XRF method may be suitable. For Mo, the correlation was weak and XRF cannot be recommended. Selenium could not be detected in samples prepared by either method. Hand-held XRF spectrometry was a practical method to determine liver concentrations of specific trace elements under African conditions and may significantly reduce the turn-around time of analysis, but unfortunately the apparatus is expensive.
Daniël E. Van Loggerenberg; Pete N. Laver; Jan G. Myburgh; Christo J. Botha. Diagnostic Value of Energy Dispersive Hand-Held X-ray Fluorescence Spectrometry in Determining Trace Element Concentrations in Ovine Liver. Biological Trace Element Research 2018, 190, 358 -361.
AMA StyleDaniël E. Van Loggerenberg, Pete N. Laver, Jan G. Myburgh, Christo J. Botha. Diagnostic Value of Energy Dispersive Hand-Held X-ray Fluorescence Spectrometry in Determining Trace Element Concentrations in Ovine Liver. Biological Trace Element Research. 2018; 190 (2):358-361.
Chicago/Turabian StyleDaniël E. Van Loggerenberg; Pete N. Laver; Jan G. Myburgh; Christo J. Botha. 2018. "Diagnostic Value of Energy Dispersive Hand-Held X-ray Fluorescence Spectrometry in Determining Trace Element Concentrations in Ovine Liver." Biological Trace Element Research 190, no. 2: 358-361.
A tremorgenic syndrome occurs in dogs following ingestion of moldy walnuts, and Penicillium crustosum has been implicated as the offending fungus. This is the first report of suspected moldy walnut toxicosis in man. An adult male ingested approximately eight fungal-infected walnut kernels and after 12 h experienced tremors, generalized pain, incoordination, confusion, anxiety, and diaphoresis. Following symptomatic and supportive treatment at a local hospital, the man made an uneventful recovery. A batch of walnuts (approximately 20) was submitted for mycological culturing and identification as well as for mycotoxin analysis. Penicillium crustosum Thom was the most abundant fungus present on walnut samples, often occurring as monocultures on isolation plates. Identifications were confirmed with DNA sequences. The kernels and shells of the moldy walnuts as well as P. crustosum isolates plated on yeast extract sucrose (YES) and Czapek yeast autolysate (CYA) agars and incubated in the dark at 25 °C for 7 days were screened for tremorgenic mycotoxins and known P. crustosum metabolites using a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method. A relatively low penitrem A concentration of only 1.9 ng/g was detected on the walnut kernels when compared to roquefortine C concentrations of 21.7 μg/g. A similar result was obtained from P. crustosum isolates cultured on YES and CYA, with penitrem A concentrations much lower (0.6–6.4 μg per g mycelium/agar) compared to roquefortine C concentrations (172–1225 μg/g). The authors surmised that besides penitrem A, roquefortine C might also play an additive or synergistic role in intoxication of man.
C. J. Botha; Cobus M Visagie; Michael Sulyok. Putative neuromycotoxicoses in an adult male following ingestion of moldy walnuts. Mycotoxin Research 2018, 35, 9 -16.
AMA StyleC. J. Botha, Cobus M Visagie, Michael Sulyok. Putative neuromycotoxicoses in an adult male following ingestion of moldy walnuts. Mycotoxin Research. 2018; 35 (1):9-16.
Chicago/Turabian StyleC. J. Botha; Cobus M Visagie; Michael Sulyok. 2018. "Putative neuromycotoxicoses in an adult male following ingestion of moldy walnuts." Mycotoxin Research 35, no. 1: 9-16.
Reports were received that Cape spurfowl (Pternistis capensis) fell during flight and scrambled uncoordinatedly for cover and some died. Three carcases were submitted for necropsy examination, which revealed mainly congestion of the carcases and haemorrhages. Common causes of acute mortalities in birds were first excluded, but there was a history of possible exposure to imidacloprid-treated barley seeds. Imidacloprid, a neonicotinoid insecticide, is used to protect various crops against invertebrate pests. The combined crop contents and pooled liver samples collected from the Cape spurfowl during necropsy were submitted for liquid chromatography–high-resolution mass spectrometry (LC-HRMS) for imidacloprid analysis. Imidacloprid and several of its metabolites were detected in the samples. Farmers should cover sown seeds with a layer of soil and remove any spilled seeds, as granivorous birds are susceptible to imidacloprid intoxication. Regulatory authorities should re-evaluate the risk posed by imidacloprid-treated seeds for pollinators and granivorous birds.
Christo J. Botha; Elizabeth C. Du Plessis; Heleen Coetser; Magda Rosemann. Analytical confirmation of imidacloprid poisoning in granivorous Cape spurfowl (Pternistis capensis). Journal of the South African Veterinary Association 2018, 89, e1 -e5.
AMA StyleChristo J. Botha, Elizabeth C. Du Plessis, Heleen Coetser, Magda Rosemann. Analytical confirmation of imidacloprid poisoning in granivorous Cape spurfowl (Pternistis capensis). Journal of the South African Veterinary Association. 2018; 89 ():e1-e5.
Chicago/Turabian StyleChristo J. Botha; Elizabeth C. Du Plessis; Heleen Coetser; Magda Rosemann. 2018. "Analytical confirmation of imidacloprid poisoning in granivorous Cape spurfowl (Pternistis capensis)." Journal of the South African Veterinary Association 89, no. : e1-e5.
Cyanobacteria are known for their extensive and highly visible blooms in rivers or dams in Africa. One of the most important cyanobacteria is Microcystis aeruginosa which can synthesise various microcystins that may affect the health of humans and animals. Accurate and efficient detection of microcystins in water is thus important for public and veterinary health. Two enzyme-linked immunosorbent assays (ELISA), a commercially-available ELISA kit (Abraxis) and a newly-developed Norwegian ELISA (putatively cheaper and more robust) were used to detect microcystins in fresh water in South Africa. Water samples were collected monthly at two sites, the Hartbeespoort Dam and a crocodile breeding dam. Extremely high microcystin concentrations (exceeding 360 μg L−1) were detected in the Hartbeespoort Dam during January 2015, whereas the microcystin concentrations in the crocodile breeding dam peaked during March–April 2015. Both ELISAs were positively correlated when analysing water samples ‘as is’ and following resin adsorption and methanol extraction. However, following resin adsorption and methanol extraction of the water samples, the correlation between the two assays was much stronger. These results suggests that the two ELISAs provide comparable results. If the Norwegian-developed ELISA can be packaged and made available as a user-friendly kit, it could be used successfully in surveillance programmes to monitor microcystin concentrations in fresh water bodies in Africa.
C. J. Botha; P. N. Laver; A. Singo; E. A. Venter; G. C. H. Ferreira; M. Rösemann; J. G. Myburgh. Evaluation of a Norwegian-developed ELISA to determine microcystin concentrations in fresh water. Water Supply 2018, 19, 743 -752.
AMA StyleC. J. Botha, P. N. Laver, A. Singo, E. A. Venter, G. C. H. Ferreira, M. Rösemann, J. G. Myburgh. Evaluation of a Norwegian-developed ELISA to determine microcystin concentrations in fresh water. Water Supply. 2018; 19 (3):743-752.
Chicago/Turabian StyleC. J. Botha; P. N. Laver; A. Singo; E. A. Venter; G. C. H. Ferreira; M. Rösemann; J. G. Myburgh. 2018. "Evaluation of a Norwegian-developed ELISA to determine microcystin concentrations in fresh water." Water Supply 19, no. 3: 743-752.
Aspergillus clavatus poisoning is a neuromycotoxicosis of ruminants that occurs sporadically across the world after ingestion of infected feedstuffs. Although various toxic metabolites are synthesized by the fungus, it is not clear which specific or group of mycotoxins induces the syndrome. A. clavatus isolates were deposited in the culture collection of the Biosystematics Division, Plant Protection Research Institute, Agricultural Research Council during incidences of livestock poisoning (1988–2016). Six isolates were still viable and these plus three other South African isolates that were also previously deposited in the collection were positively identified as A. clavatus based on morphology and ß-tubulin sequence data. The cultures were screened for multiple mycotoxins using a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method. Twelve A. clavatus metabolites were detected. The concentrations of the tremorgenic mycotoxins (i.e., tryptoquivaline A and its related metabolites deoxytryptoquivaline A and deoxynortryptoquivaline) were higher than patulin and cytochalasin E. Livestock owners should not feed A. clavatus-infected material to ruminants as all the South African A. clavatus isolates synthesized the same compounds when cultured under similar conditions.
C. J. Botha; Mariette Truter; Michael Sulyok. Multimycotoxin analysis of South African Aspergillus clavatus isolates. Mycotoxin Research 2017, 34, 91 -97.
AMA StyleC. J. Botha, Mariette Truter, Michael Sulyok. Multimycotoxin analysis of South African Aspergillus clavatus isolates. Mycotoxin Research. 2017; 34 (2):91-97.
Chicago/Turabian StyleC. J. Botha; Mariette Truter; Michael Sulyok. 2017. "Multimycotoxin analysis of South African Aspergillus clavatus isolates." Mycotoxin Research 34, no. 2: 91-97.
Cyanobacteria or blue green algae are known for their extensive and highly visible blooms in eutrophic, stagnant freshwater bodies. Climate change and global warming have also contributed to a rise in toxic cyanobacterial blooms. One of the most important cyanobacteria is Microcystis aeruginosa, which can synthesize various microcystins that can affect the health of terrestrial and aquatic animals. Commercial Nile crocodile (Crocodylus niloticus) farming in South Africa is based on keeping breeders (adult males and females) in big dams on farms (captive-bred approach). Unfortunately, cyanobacterial blooms in the breeder dams are a concern to farm owners, managers and veterinarians. The main objectives of this research project were to determine if microcystins were present in the contents of crocodile eggs and the liver and yolk of dead hatchlings, and to determine if the reduced hatchability on commercial farms might be caused by these toxins. Furthermore, the concentration of microcystins in the breeder dam was monitored on a monthly basis spanning the ovulation and egg laying period. During the hatching season microcystin concentrations in unfertilised eggs, egg shell membranes and in the yolk and liver of dead hatchlings were determined using liquid chromatography-high resolution mass spectrometry (LC-HRMS). Microcystins were detected in Nile crocodile egg and hatchling samples. Microcystin (MC-LR, MC-RR, MC-YR) concentrations in the crocodile egg and hatchling samples collected from clutches with a good hatching rate (≥90%) ranged between 0 and 1.76 ng g-1, with the highest concentration in the egg shell membranes. Microcystin concentrations in samples collected from clutches with a bad hatching rate (≤10%) ranged from 0 - 1.63 ng g-1 with the highest concentration detected in the hatchling yolk. However, the concentrations were probably underestimated as the percentage recovery from spiked samples was very low with the extraction method employed. Bayesian analysis suggests that the liver, yolk and unfertilised egg all have similar microcystin concentrations, while the membranes have (with moderate to high certainty) higher microcystin concentrations. There appears to be no difference in microcystin concentrations among good and bad clutches across all tissue types or within a specific tissue type, but due to the small sample size, it was not possible to determine whether microcystin affected the hatchability of Nile crocodile eggs. However, vertical transmission of microcystin variants to the Nile crocodile egg does occur and the possible implications for the survival of wild Nile crocodile populations should be ascertained.
Alukhethi Singo; Jan G. Myburgh; Peter N. Laver; Elizabeth A. Venter; Gezina C.H. Ferreira; Gertruida M. Rösemann; Christo J. Botha. Vertical transmission of microcystins to Nile crocodile ( Crocodylus niloticus ) eggs. Toxicon 2017, 134, 50 -56.
AMA StyleAlukhethi Singo, Jan G. Myburgh, Peter N. Laver, Elizabeth A. Venter, Gezina C.H. Ferreira, Gertruida M. Rösemann, Christo J. Botha. Vertical transmission of microcystins to Nile crocodile ( Crocodylus niloticus ) eggs. Toxicon. 2017; 134 ():50-56.
Chicago/Turabian StyleAlukhethi Singo; Jan G. Myburgh; Peter N. Laver; Elizabeth A. Venter; Gezina C.H. Ferreira; Gertruida M. Rösemann; Christo J. Botha. 2017. "Vertical transmission of microcystins to Nile crocodile ( Crocodylus niloticus ) eggs." Toxicon 134, no. : 50-56.
Geigeria poisoning in sheep, locally known as ‘vermeersiekte’, is an economically important plant poisoning in southern Africa. The toxic principles contained by the toxic plants are believed to be several sesquiterpene lactones, such as geigerin, vermeeric acid and vermeerin, which cause striated muscle lesions in small stock. Because of ethical issues surrounding the use of live animals in toxicity studies, there is currently a dire need to establish an in vitro model that can be used to replace traditional animal experimentation. The objective of this study was to determine the cytotoxicity of geigerin in a murine myoblast cell line (C2C12) using methyl-thiazol-tetrazolium (MTT) and lactate dehydrogenase (LDH) assays, annexin V and propidium iodide (PI) flow cytometry and transmission electron microscopy (TEM). Mouse myoblasts were exposed to 2.0 mM, 2.5 mM and 5.0 mM geigerin for 24, 48 and 72 h. A concentration-dependent cytotoxic response was observed. Apoptosis was detected by means of annexin V flow cytometry during the first 24 h and apoptotic bodies were also visible on TEM. According to the LDH and PI flow cytometry results, myoblast cell membranes were not injured. We concluded that the murine myoblast cell line (C2C12) is a suitable model for future studies planned to evaluate the cytotoxicity of other and combinations of sesquiterpene lactones, with and without metabolic activation, implicated in ‘vermeersiekte’ and to elucidate the subcellular effects of these myotoxins on cultured myoblasts.
Christo J. Botha; Sarah J. Clift; Gezina C.H. Ferreira; Mxolisi G. Masango. Geigerin-induced cytotoxicity in a murine myoblast cell line (C2C12). ONDERSTEPOORT Journal of Veterinary Research 2017, 84, 7 pages -e7.
AMA StyleChristo J. Botha, Sarah J. Clift, Gezina C.H. Ferreira, Mxolisi G. Masango. Geigerin-induced cytotoxicity in a murine myoblast cell line (C2C12). ONDERSTEPOORT Journal of Veterinary Research. 2017; 84 (1):7 pages-e7.
Chicago/Turabian StyleChristo J. Botha; Sarah J. Clift; Gezina C.H. Ferreira; Mxolisi G. Masango. 2017. "Geigerin-induced cytotoxicity in a murine myoblast cell line (C2C12)." ONDERSTEPOORT Journal of Veterinary Research 84, no. 1: 7 pages-e7.
V. Naidoo; K. Wolter; Christo Botha. Lead ingestion as a potential contributing factor to the decline in vulture populations in southern Africa. Environmental Research 2017, 152, 150 -156.
AMA StyleV. Naidoo, K. Wolter, Christo Botha. Lead ingestion as a potential contributing factor to the decline in vulture populations in southern Africa. Environmental Research. 2017; 152 ():150-156.
Chicago/Turabian StyleV. Naidoo; K. Wolter; Christo Botha. 2017. "Lead ingestion as a potential contributing factor to the decline in vulture populations in southern Africa." Environmental Research 152, no. : 150-156.
In the present study, the developmental (including fertility) and endocrine-disruptive effects in relation to chemical burden in male and female Nile crocodiles (Crocodylus niloticus), from a commercial crocodile farm in the Brits district, South Africa, exposed to various anthropogenic aquatic contaminants from the natural environment was investigated. Hepatic transcript levels for vitellogenin (Vtg), zona pellucida (ZP) and ERα (also in gonads) were analyzed using real-time PCR. Plasma estradiol-17β (E2), testosterone (T) and 11-ketotestosterone (11-KT) were analyzed using enzyme immunoassay. Gonadal aromatase and hepatic testosterone metabolism (6β-hydroxylase (6β-OHase)) were analyzed using biochemical methods. Overall, there is high and abnormal number (%) of infertile and banded eggs during the studied reproductive seasons, showing up to 57 and 34% of infertile eggs in the 2009/2010 and 2013/2014 seasons, respectively. In addition, the percentage of banded eggs ranged between 10–19% during the period of 2009–2014 seasons. While hepatic ERα, Vtg, ZP mRNA and 6β-OHase, were equally expressed in female and male crocodiles, gonadal ERα mRNA and aromatase activity were significantly higher in females compared to male crocodiles. On the other hand, plasma T and 11-KT levels were significantly higher in males, compared to female crocodiles. Principal component analysis (PCA) produced significant grouping that revealed correlative relationships between reproductive/endocrine-disruptive variables and liver contaminant burden, that further relates to measured contaminants in the natural environment. The overall results suggest that these captive pre-slaughter farm crocodiles exhibited responses to anthropogenic aquatic contaminants with potentially relevant consequences on key reproductive and endocrine pathways and these responses may be established as relevant species endocrine disruptor biomarkers of exposure and effects in this threatened species.
Augustine Arukwe; Jan Myburgh; Håkon A. Langberg; Aina O. Adeogun; Idunn Godal Braa; Monika Moeder; Daniel Schlenk; Jordan Paul Crago; Francesco Regoli; Christo Botha. Developmental alterations and endocrine-disruptive responses in farmed Nile crocodiles ( Crocodylus niloticus ) exposed to contaminants from the Crocodile River, South Africa. Aquatic Toxicology 2016, 173, 83 -93.
AMA StyleAugustine Arukwe, Jan Myburgh, Håkon A. Langberg, Aina O. Adeogun, Idunn Godal Braa, Monika Moeder, Daniel Schlenk, Jordan Paul Crago, Francesco Regoli, Christo Botha. Developmental alterations and endocrine-disruptive responses in farmed Nile crocodiles ( Crocodylus niloticus ) exposed to contaminants from the Crocodile River, South Africa. Aquatic Toxicology. 2016; 173 ():83-93.
Chicago/Turabian StyleAugustine Arukwe; Jan Myburgh; Håkon A. Langberg; Aina O. Adeogun; Idunn Godal Braa; Monika Moeder; Daniel Schlenk; Jordan Paul Crago; Francesco Regoli; Christo Botha. 2016. "Developmental alterations and endocrine-disruptive responses in farmed Nile crocodiles ( Crocodylus niloticus ) exposed to contaminants from the Crocodile River, South Africa." Aquatic Toxicology 173, no. : 83-93.
Bufadienolide-type cardiac glycosides have a worldwide distribution and are mainly synthesized by plants, but there are also animal sources. In South Africa, members of three genera of the Crassulaceae (Cotyledon, Tylecodon and Kalanchoe) cause a unique chronic form of cardiac glycoside poisoning, predominantly in small stock. This paretic/paralytic condition is referred to as “krimpsiekte”, cotyledonosis or “nenta”. “Krimpsiekte” is a plant poisoning only reported from South Africa and is regarded as the most important plant poisoning of small stock in the semi-arid Little Karoo and southern fringes of the Great Karoo. The toxicosis is caused by cumulative bufadienolides which have neurotoxic properties. Four types of cumulative neurotoxic bufadienolides, namely cotyledoside, and the tyledosides, orbicusides and lanceotoxins, have been isolated. Based on the structure activity relationships and certain toxicokinetic parameters possible reasons for their accumulation are presented. Consumption of edible tissues from animals that have ingested these plants poses a potential risk to humans.
Christo Botha. Potential Health Risks Posed by Plant-Derived Cumulative Neurotoxic Bufadienolides in South Africa. Molecules 2016, 21, 348 .
AMA StyleChristo Botha. Potential Health Risks Posed by Plant-Derived Cumulative Neurotoxic Bufadienolides in South Africa. Molecules. 2016; 21 (3):348.
Chicago/Turabian StyleChristo Botha. 2016. "Potential Health Risks Posed by Plant-Derived Cumulative Neurotoxic Bufadienolides in South Africa." Molecules 21, no. 3: 348.
Diplodiosis, a neuromycotoxicosis of cattle and sheep grazing on mouldy cobs infected by Stenocarpella maydis, is considered the last major veterinary mycotoxicosis for which the causative mycotoxin is still unknown. The current study was aimed at characterizing the cell death observed in mouse neuroblastoma (Neuro-2a), Chinese hamster ovary (CHO-K1) and Madin–Darby bovine kidney (MDBK) cell lines exposed to the S. maydis metabolites (i.e. diplodiatoxin and dipmatol) by investigating the roles of necrosis and apoptosis. Necrosis was investigated using the lactate dehydrogenase (LDH) leakage and propidium iodide (PI) flow cytometry assays and apoptosis was evaluated using the caspase-3/7 and Annexin V flow cytometry assays. In addition, transmission electron microscopy (TEM) was used to correlate the cell death pathways observed in this study with their typical morphologies. Both diplodiatoxin and dipmatol (750 μM) induced necrosis and caspase-dependent apoptosis in Neuro-2a, CHO-K1 and MDBK cells. Ultrastructurally, the two mycotoxins induced mitochondrial damage, cytoplasmic vacuolation and nuclear fragmentation in the three cell lines. These findings have laid a foundation for future studies aimed at elucidating in detail the mechanism of action of the S. maydis metabolites.This work was supported by the International Foundation for Science (IFS), Stockholm, Sweden, through a grant to MG Masango (Grantee Number : B/5114-1), the National Research Foundation (NRF) and the Joy Liebenberg Trust Fund (Grantee Number : MasangoJT).http://www.elsevier.com/locate/toxiconhb2016Paraclinical Science
Mxolisi G. Masango; Charlotte E. Ellis; Christo Botha. Characterization of cell death caused by diplodiatoxin and dipmatol, toxic metabolites of Stenocarpella maydis. Toxicon 2015, 102, 14 -24.
AMA StyleMxolisi G. Masango, Charlotte E. Ellis, Christo Botha. Characterization of cell death caused by diplodiatoxin and dipmatol, toxic metabolites of Stenocarpella maydis. Toxicon. 2015; 102 ():14-24.
Chicago/Turabian StyleMxolisi G. Masango; Charlotte E. Ellis; Christo Botha. 2015. "Characterization of cell death caused by diplodiatoxin and dipmatol, toxic metabolites of Stenocarpella maydis." Toxicon 102, no. : 14-24.