Non-invasive sampling of bats reflects their potential as ecological indicators of elemental exposure in a diamond mining area, northern Limpopo Province, South Africa.

Bats have been proposed as reliable bioindicators for monitoring bioaccumulation of elements and chemicals in natural and transformed ecosystems. Non-invasive methods are becoming more popular as research moves away from destructive methodologies. We present the first concentrations of 23 elements in Mops condylurus and Tadarida aegyptiaca (Molossidae) fur and blood from an opencast diamond mine and reference area using inductively coupled plasma mass spectrometry (ICP-MS). Concentrations of B, K, Rb and Cd in the bats' fur were significantly higher in the mining footprint compared to the reference area (P < 0.05). Other elements such as Zn and Hg were significantly higher in the blood of bats from the mining footprint than the reference area (P < 0.05), whereas Mn was significantly higher in the blood of bats from the reference area than from the mining footprint (P < 0.05). Sixteen of the 22 elements above the limit of detection, with the exception of Ba, were significantly higher in the fur samples than in the blood due to elements being incorporated over time into the fur as it grows, whereas blood reveals short-term exposure to elements. Concentrations of most of the elements were reasonably low except Al, Fe and Zn. In general, the element concentrations particularly in the fur samples were comparable with other international studies reporting elemental fur concentrations from anthropogenically impacted and natural areas. Fur and blood have the potential to be viable indicators of environmental toxicity, but research is required on toxic thresholds and physiological and ecological unknowns around element concentrations in bat tissues and organs.

Endocrine Disruptors and Health Effects in Africa: A Call for Action.

BACKGROUND: Africa faces a number of unique environmental challenges. Unfortunately, it lacks the infrastructure needed to support the comprehensive environmental studies that could provide the scientific basis to inform environmental policies. There are a number of known sources of endocrine-disrupting chemicals (EDCs) and other hazardous chemicals in Africa. However, a coordinated approach to identify and monitor these contaminants and to develop strategies for public health interventions has not yet been made. OBJECTIVES: This commentary summarizes the scientific evidence presented by experts at the First African Endocrine Disruptors meeting. We describe a "call to action" to utilize the available scientific knowledge to address the impact of EDCs on human and wildlife health in Africa. DISCUSSION: We identify existing knowledge gaps about exposures to EDCs in Africa and describe how well-designed research strategies are needed to address these gaps. A lack of resources for research and a lag in policy implementation slows down intervention strategies and poses a challenge to advancing future health in Africa. CONCLUSION: To address the many challenges posed by EDCs, we argue that Africans should take the lead in prioritization and evaluation of environmental hazards, including EDCs. We recommend the institution of education and training programs for chemical users, adoption of the precautionary principle, establishment of biomonitoring programs, and funding of community-based epidemiology and wildlife research programs led and funded by African institutes and private companies. https://doi.org/10.1289/EHP1774.

Immunohistochemical study of nuclear changes associated with male germ cell death and spermiogenesis.

In a previous study on the effects of gestational and lactational exposure of para-nonylphenol on male rats, we noted in both induced and uninduced rats, that variations in cleaved caspase-3 immunostaining patterns were associated with distinct nuclear alterations in mainly basally located germ cells (spermatogonia and preleptotene spermatocytes). These were re-analysed and compared with cleaved caspase-3-labeled germ cells in the aging human and the spermatogenically active catfish testis. In the rat testes, cytoplasmic immunostaining was progressively associated with lateral compression of the nucleus, its break up into large pieces which can contain immunostained marginated chromatin masses. The pale remnants of the nucleus continued to shrink in size concomitant with the appearance of blue-purplish stained regions in the cytoplasm similar in color to the condensed chromatin in spermatids, a condition which was TUNEL-negative. These large clumps of chromatin also eventually disappeared, giving rise to cells resembling cytoplasmic ghosts, a condition which was TUNEL-positive. By contrast, the immunolabeled nuclei of human and catfish germ cells condensed into a single mass, after which they lost immunoreactivity. To exclude the possibility that these observations could reflect alterations in Sertoli nuclei, rat testicular sections were probed with a mouse anti-human GATA-4 monoclonal (MHM) antibody. The MHM was, however, the second of two GATA-4 antibodies tested, with a goat anti-mouse polyclonal (GMP) initially used to label the rat Sertoli nuclei. GMP unexpectedly, but distinctly labeled the complete development of the acrosome in the rat testis, a fortuitous finding with utility for staging of the seminiferous epithelium.

Histopathological changes in the reproductive system (ovaries and testes) of Oreochromis mossambicus following exposure to DDT.

This study assesses the effects of 1,1-bis (4-chlorophenyl)-2,2,2-trichloroethane (DDT) on the reproduction and gonadal histology of adult Mozambique tipalia (Oreochromis mossambicus). The fish were allowed to breed, following exposure to 2 and 5µg/l of waterborne technical-grade DDT for 40 days. Fertilized eggs were artificially incubated. In the 5µg/l exposure, posthatch survival was significantly lower, and prevalence of larval skeletal deformities significantly higher, compared to the control (p<0.05). Incomplete axial development was the common gross deformity in posthatch larvae, caused by failure to develop chondroblasts posterior to the buccopharyngeal cavity. There were no significant differences in the gonadosomatic index of exposed and non-exposed male and female adults. The exposure caused increased oocyte atresia in the ovaries and disorganization of seminiferous lobules in the testes of adults. DDT exposure reduced survival and increased deformities in larvae, at levels that did not cause severe histopathological changes to parental gonads.

Testicular apoptosis in feral Clarias gariepinus using TUNEL and cleaved caspase-3 immunohistochemistry.

This paper reports on the mechanistic basis of cellular death in the testis of Clarias gariepinus using the TUNEL and caspase-3 immunohistochemistry. It was also aimed to determine the testicular zone most suitable for the quantification of testicular apoptosis. The results showed that based on its immuno-expression patterns, activated caspase-3 has a clear and defined role in the progression of germ cell apoptosis in spermatogenically active catfish testis. Caspase-3 activation, and not TUNEL-detected DNA fragmentation, is associated with condensation of chromatin into a single mass. Testes of spermatogenically active catfish consist of spermatogenic, mature and spent tubules. Spermatogenic tubules were concluded to be the most suitable zone for the quantification of testicular cell death ratios as apoptotic events occurred predominantly in the secondary spermatocytes. The findings of this study will form the basis to link apoptotic events in the testes of C. gariepinus with the effects of EDC exposure in future studies.