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Aspects of the reproduction of male and female African penguins (Spheniscus demersus) with special reference to sperm biology and cryopreservation
(University of the Western Cape, 2018) Mafunda, Patrick Siyambulela
In the marine environment, penguins have been described as curators and serve a critical role in ecological balance. The African penguin (Spheniscus demersus) has undergone a rapid population decline, mainly due to disturbances in their natural habitat. The African penguin was up-listed from vulnerable to endangered on the IUCN Red List for Threatened Species in 2010 and thus urgent conservation action is required. Integral to long-term conservation action of any species is a basic knowledge of its reproductive biology, which is currently lacking for African penguins. The main aim of this investigation was to evaluate techniques for the collection of semen in African penguin and to determine sperm quality in order to cryopreserve sperm for in vitro fertilization (IVF) purposes of captive and wild populations. Semen was collected once a week during two breeding seasons from two captive African penguins. Ejaculates (n=51) were obtained over two breeding seasons (Jan-Feb and Jun-Oct) and evaluated for semen volume, sperm concentration, sperm vitality, sperm motility and sperm morphology. In addition twelve (six females and six males, n=4 were breeding pairs) captive African penguins were monitored for hormone (estradiol, testosterone, progesterone) levels prior to and after the egg-laying period. The testes were asymmetrical in adults, with the right testis on average shorter in length, width and volume respectively (16.80 ± 4.37 mm; 7.93 ± 2.63 mm; 0.75 mL) compared to the left testis (25.39 ± 5.85 mm; 11.48 ± 4.09 mm; 2.46 mL). The ovaries displayed variation in shape and size among the penguins, the adult ovary has a mean length of 25.72 ± 5.37 mm and a mean width of 9.02 ± 3.87 mm. The Follicles ranged from white small follicles with a diameter of <0.01 mm to mature, yellow large follicles which had a maximum diameter of 22 mm. The testis and ovary histological features such as structure, weight and size, can give a clear indication of breeding status in African penguin. Estradiol levels showed a biphasic pattern in three of the four breeding females, whereas no clear pattern could be followed in other hormones investigated. Semen volume ranged from 0.01 to 0.1 ml, sperm concentration from 802.6 to 7808.8 x106 /ml and total number of sperm per sample ranged from 3.42 to 740.18 x106. The percentage total motility was between 40.1 and 87.1%. The recorded velocities was for curvilinear velocity (VCL 81.5 ± 10.2 μm/s), straight-line velocity (VSL 42.72 ± 7.3 μm/s) and average path velocity (VAP 59.4 ± 8.2 μm/s), and kinematics at straightness of track (STR 71.4 ± 8.9 %), linearity of track (LIN 52.4 ± 8.1 %), amplitude of lateral head displacement (ALH 2.3 ± 0.2 μm) and beat cross frequency (BCF 16.8 ± 3.8 Hz). Sperm quality and semen parameters were similar across all samples collected over breeding seasons. In comparison to fresh semen, percentage total motility of thawed semen decreased to 16.8% after two hours in liquid nitrogen. Since spermatozoa differ notably in their morphology within species, phase-contrast microscopy, scanning electron microscopy and transmission electron microscopy were used to examine structural abnormalities. The sperm morphology is almost identical and largely resembles that of non-passerine birds in terms of the filiform head, small acrosome and mid-piece containing 13 spherical mitochondria, arranged around the proximal and distal centrioles in a single helix. The ultrastructure of the sperm principal piece revealed the typical 9+2 microtubular arrangement without any outer dense fibres. An unusual feature was the occurrence of multiple axonemes contained in one plasmalemma in 4% of spermatozoa. Multiple axonemes found in penguin flagella could be an apomorphism that distinguish them from other bird spermatozoa. This research represents a critical step in the conservation and long-term survival of the African penguin by evaluating techniques for the collection and determination of sperm quality in order to cryopreserve sperm for IVF.
The role of high-risk human papillomavirus in periocular cancers
(University of the Western Cape, 2018) Afrogheh, Amir H
Purpose: High risk human papillomavirus (HR-HPV) is well established as a causative agent of squamous cell carcinoma (SCC) of the orophaynx. HR-HPV has also been reported in periocular cancers and precancers, but controversy exists about its overall incidence and clinicopathologic profile. The purpose of this study is to evaluate the role of HR-HPV infection in periocular cancers and precancers, using multiple methods of detection. Design: Retrospective observational case series with laboratory investigations. Methods: Sequential surgical samples of 87 carcinomas (invasive SCC, SCC in situ and sebaceous carcinoma) from three different periocular sites (conjunctiva, lacrimal sac and the eyelid) diagnosed over a 15-year period (2000-2015) were selected for evaluation. Unstained paraffin sections of 87 cases of periocular carcinomas were analyzed with immunohistochemistry (IHC) for p16 as a screening test. p16 positive conjunctival- and lacrimal sac SCC were further evaluated for HR-HPV using DNA in situ hybridization (DNA ISH), and a subset was also analyzed by DNA Polymerase Chain Reaction (DNA PCR). p16 positive periocular sebaceous carcinomas (SC) were analyzed with PCR, and a subset of 18 cases was further studied with a novel method of mRNA ISH, an advanced technique with an enhanced sensitivity and specificity. Relevant patient clinical information was obtained from review of the electronic medical records. Results: Of 43 ocular surface squamous cell neoplasia (OSSN), 30% (n=13; 8 SCC in situ and 5 invasive SCC), were positive for HR-HPV. The HPV-positive OSSN occurred in 8 men and 5 women with a mean age of 60 years (range: 39 to 94 years). HPV type16 was detected in all conjunctival cases evaluated by DNA PCR. All 5 conjunctival invasive SCC (I-SCC) showed a non-keratinizing (n=4) or partially keratinizing (n=1) histomorphology, and were managed by simple excision. In contrast, the HPV-negative conjunctival I-SCC were predominantly keratinizing (11 keratinizing, 2 non-keratinizing). Of 9 lacrimal sac I-SCC (LSSCC), 66.7% (n=6/9) were positive for HR-HPV by p16 and DNA ISH; HPV subtypes were HPV-16 (n=5) and HPV-58 (n=1). In addition, two p16-positive cases with negative DNA ISH results were HR-HPV positive (HPV-16 and HPV-33) when evaluated by DNA PCR, suggesting that the rate of HRHPV positivity among the LSSCC may be as high as 89% (n=8/9). The combined group of HR-HPV positive LSSCC occurred in 4 men and 4 women with a mean age of 60 years (range: 34 to 71 years). Seven of the 8 HPV-positive LSSCC (87.5%) had a non-keratinizing or partially keratinizing histomorphology while 1 case (12.5%) was predominantly keratinizing. Strong immunohistochemical p16 positivity was present in 29 of 35 cases of periocular SC (82.9%). The selected 18 p16-positive cases tested were negative for HR-HPV using mRNA ISH. DNA PCR was unequivocal with adequate DNA isolated in 24 cases, 23 of which were negative for HR-HPV. One case was positive for HPV type 16, which was found to be a false positive as determined by mRNA ISH negativity. Conclusion: The presence of HR-HPV in 30% of OSSN and at least 66.7% of LSSCC confirms HR HPV as an important etiologic agent at these sites. No evidence was found for HR-HPV as an etiologic agent in the development of periocular SC using DNA PCR, and mRNA ISH to maximize sensitivity and specificity. p16 overexpression is common in periocular SC but unrelated to HR-HPV status. Immunohistochemical testing for p16, however, can be a valuable adjunct for identifying pagetoid intraepithelial spread of disease and small invasive cellular clusters. Although p16 may be used as a surrogate marker for HR-HPV status in conjuctival- and lacrimal sac carcinomas, this interpretation of p16 positivity is not applicable to periocular SC.
Electrochemical performance of ZnCo2O4: versatility in applications
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Sitole, Soyama; Ross, Natasha; Bilibana, Mawethu Pascoe
Zinc cobaltite (ZnCo2O4) is a ternary metal oxide found in spinel with promising properties for various applications. Optimizing its catalytic activity requires an understanding of its electrochemical behavior. The electrochemical properties of ZnCo2O4 have significantly improved due to recent developments in nanostructuring, doping, surface modification, hybridization, structural engineering, and electrochemical activation. These improvements have inspired and motivated researchers by presenting the latest developments in the field. The spinel structure, coupled with the redox properties of cobalt ions, semiconducting characteristics, and electrocatalytic potential, positions ZnCo2O4 as a versatile material for several electrochemical energy storage and conversion systems. This review explores these advancements; the notable properties of ZnCo2O4; and its applications in sensors, batteries, photovoltaics, and supercapacitors.
Domestic investment in primary agriculture in South Africa
(University of the Western Cape, 2026) Small, Danielle Francine
In recent years, the South African farming sector has been experiencing important restructurings that pertained to the industrialisation of agriculture.2 These restructurings can be attributed to the development of farm financing and investment instruments by the increasing engagement of corporate entities interested in financing the sector in return for ownership of the land by incorporating primary production into their portfolios.3 When examining the performance of the South African agricultural sector and the policy reorganisation, it is necessary to take heed of its historical context. It was during the 1950s and 1960s that the government invested in research and development, infrastructure, extension services, direct subsidies for conservation works and debt relief, which grew the commercial sector’s agricultural output with guaranteed markets and prices for most farm commodities.4 However, by 1979 the economy had moved into a recession and economic policy prioritised its deregulation of the financial markets in South Africa.5 These events birthed the process of liberalisation in trade and deregulation of agriculture that was only partially completed by the early 1990s.6 The undeniable consequences of these transformations are the effects to the family farmer’s status as landowner to now being merely a service provider.7 In response to the failing land reform projects and in the absence of alternative successful investments and production models, these transformations are of course supported by the South African government.8
Gender discrimination in the South African workplace: a critical analysis
(University of the Western Cape, 2026) Dlomo, Nokwanda Zoleka
The South African Constitution guarantees the right to equality and protects everyone from unfair discrimination. In terms of right to equality contained in section 9 of the Constitution of South Africa, no person may unfairly discriminate directly or indirectly against anyone on one or more grounds in terms of subsection (3).1 Section 9(4) of the Constitution further directs that “national legislation must be enacted to prevent or prohibit unfair discrimination”.2 The Employment Equity Act 55 of 1998, as amended was promulgated to give effect to section 9 of the Constitution. Research shows that females are still subjected to gender discrimination. This study contains a discussion on the laws governing gender discrimination in South Africa. Reference is made to the relevant constitutional provisions and the statutory provisions that aim to protect employees from gender discrimination. A comparison is made between the laws governing gender discrimination in South Africa, Canada and Germany to determine whether there are any lessons that South Africa can learn from Germany and Canada. The purpose of the study is to determine the extent to which the South African legislative framework protects female employees against gender discrimination and to determine whether the provisions governing gender discrimination in South Africa should be amended and/or supplemented. This is done by examining case law, the provisions contained in statutes and the contents of journal articles.