Research Publications (Applied Sciences)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/213

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The antimosquito properties of extracts from flowering plants in South Africa
(NCBI, 2013) Chalannavar, Raju K.; Hurinanthan, Vashka; Singh, Alveera; Venugopala, Katharigatta Narayanaswamy; Gleiser, Raquel M.; Baijnath, Himansu; Odhav, Bharti
Extracts of selected flowering plants, which are considered eco-friendly, are used for the treatment of numerous ailments and vector control worldwide. This has resulted in approximately 25 per cent of currently used drugs being derived from herbal sources. The aqueous and methanolic extracts of twelve plant species, Psidium guajava (pink fruit), Psidium guajava (white fruit), Psidium cattleianum var. cattleianum, Psidium guineense and Psidium X durbanensis, Achyranthes aspera, Alternanthera sessilis, Guilleminea densa, Capparis tomentosa, Leonotis leonurus, Dichrostachys cinerea and Carpobrotus dimidiatus, were tested for insecticidal activity, including larvicidal, adulticidal and repellent activities against the adult female mosquito, Anopheles arabiensis. The extracts of P. guajava (white fruit), C. tomentosa, L. leonurus,D. cinerea, and C. dimidiatus exerted a pronounced inhibitory effect on adult insects, while those of P. guajava (pink fruit), P. X durbanensis, P. cattleianum var. cattleianum, P. guineense, A. aspera, A. sessilis, and G. densa were ineffective and failed to satisfy the criteria set by the World Health Organization. In the tests for repellency against An. arabiensis, all the tested aqueous and methanolic plant extracts except those of A. sessilis repelled 80-100% of mosquitoes. The most effective mosquito repellents were the methanol and aqueous extracts of P. guajava (pink fruit), P. X durbanensis, P. cattleianum var. cattleianum, P. guineense, G. densa,L. leonurus and D. cinerea, which are potential sources of cost effective mosquito repellents to be utilized in malarial endemic areas.
Artificial intelligence for the evaluation of operational parameters influencing Nitrification and Nitrifiers in an activated sludge process
(Springer Science+Business Media, 2016) Awolusi, Oluyemi Olatunji; Nasr, Mahmoud; Kumari, Sheena K.; Bux, Faizal
Abstract Nitrification at a full-scale activated sludge plant treating municipal wastewater was monitored over a period of 237 days. A combination of fluorescent in situ hybridiza-tion (FISH) and quantitative real-time polymerase chain reac-tion (qPCR) were used for identifying and quantifying the dominant nitrifiers in the plant. Adaptive neuro-fuzzy infer-ence system (ANFIS), Pearson’s correlation coefficient, and quadratic models were employed in evaluating the plant oper-ational conditions that influence the nitrification performance. The ammonia-oxidizing bacteria (AOB) abundance was with-in the range of 1.55 × 108–1.65 × 1010 copies L−1, while Nitrobacter spp. and Nitrospira spp. were 9.32 × 109–1.40 × 1011 copies L− 1 and 2.39 × 109 –3.76 × 1010 copies L−1, respectively. Specific nitrification rate (qN)was significantly affected by temperature (r 0.726, p 0.002), hy-draulic retention time (HRT) (r −0.651, p 0.009), and ammo-nia loading rate (ALR) (r 0.571, p 0.026). Additionally, AOB was considerably influenced by HRT (r −0.741, p 0.002) and temperature (r 0.517, p 0.048), while HRT negatively impact-ed Nitrospira spp. (r −0.627, p 0.012). A quadratic combina-tion of HRT and food-to-microorganism (F/M) ratio also im-pacted qN (r2 0.50), AOB (r2 0.61), and Nitrospira spp. (r2 0.72), while Nitrobacter spp. was considerably influenced by a polynomial function of F/M ratio and temperature (r2 0.49). The study demonstrated that ANFIS could be used as a tool to describe the factors influencing nitrification process at full-scale wastewater treatment plants.
Digitalization in developing maritime business environments towards ensuring sustainability
(MDPI, 2020-11-06) Kapidani, Nexhat; Bauk, Sanja; Davidson, Innocent E.
The paper focuses on assessing the level of digitalization in several developing maritime business environments in Albania, Bosnia and Herzegovina, Montenegro, and Serbia. The assessment has been done in reference to Holtham’s and Courtney’s Intelligent Information and Communication Technologies (ICT) Exploiter Model. The dimensions as maritime business system effectiveness, roles, and skills of information technology personnel, ladders of knowledge, ICT strategy, organizational culture, and manager’s mindset are analyzed. In addition, benchmarking with findings from developed maritime business environments in Croatia, Greece, Italy, and Slovenia, which belong to the European Union (EU), by using the same model, has been conducted. This is done with the aim to outline directions for improving the quality and speed of digitalization in non-EU countries, which have been functioning for decades in transitional conditions. The maritime ecosystem naturally has a tendency to be unique and to function smoothly as such. Alleviating the differences in the level and effectiveness of digitalization in developed and developing European countries is a path towards achieving this goal. By sharing their own expertise in the rational and intelligent use of ICT, developed EU countries can support developing non-EU countries towards ensuring sustainability in the entire European and worldwide maritime business ecosystem.
Functional insight into Putative Conserved Proteins of Rickettsia rickettsii and their Virulence characterization
(Bentham Science Publishers, 2015) Shahbaaz, Mohd; Bisetty, Krishna; Ahmad, Faizan
Abstract: Rickettsia rickettsii is an aerobic, Gram-negative and non-motile coccobacillus known to cause Rocky Mountain spotted fever. The sequenced genome of its 'Sheila Smith' strain contains 1,343 protein-coding genes, 3 rRNA genes and 33 transfer RNA genes. There are 680 hypothetical proteins (HPs) present in the genome of R. rickettsii. Since functions of these proteins are not validated ex-perimentally, characterization of these HPs may play a significant role in understanding the patho-genic mechanisms of R. rickettsii. Hence, functions of these HPs were annotated by in silico methods based on sequence similarity, protein clustering and protein-protein interactions. We have successfully predicted functions of 214 proteins among 680 HPs present in R. rickettsii. These annotated proteins were further classified into 88 enzymes, 59 transport and membrane proteins, 35 binding proteins, 12 structural motifs and the rest of the protein families. Moreo-ver, we identified HPs involved in virulence among 214 functionally annotated proteins. 15 HPs were classified as viru-lence factors and two proteins with the highest scores were selected for further analyses. Additionally, molecular dynam-ics simulations were performed on these selected virulent HPs in order to observe their conformational behaviors. These analyses can further be utilized in the identification of new drug targets for development of better therapeutic agents against the infections caused by R. rickettsii.
Fungal mycelium as leather alternative : a sustainable biogenic material for the fashion industry
(Elsevier BV, 2023-09) Amobonye, Ayodeji; Lalung, Japareng; Awasthi, Mukesh Kumar; Pillai, Santhosh
The global leather industry has been at the receiving end of various environmental and ethical backlash as it mainly relies on animal agriculture which contributes to deforestation, greenhouse gas emissions, and animal welfare concerns. In addition, the processing of animal hides into leather generates a huge amount of toxic chemicals, which ultimately get released into the environment. Thus, growing concern for environmental sustainability has led to the exploration of alternative materials to conventional animal- based leather. In this regard, the application of fungal leather alternatives in material technology is gaining traction because of its high biodegradability, biocompatibility, renewability, as well as its affordable and carbon-neutral growth processes. Fungal leather alternatives have been found to possess significant mechanical and physical properties, thanks to the interwoven hyphal network of the fungal mycelium, as well as antimicrobial activities which have been ascribed to their bioactive metabolites. Various fungal species, including those from the Agaricus, Fomes, Ganoderma, Phellinus, and Pleutorus genera, are currently being investigated for their potential in this area. This review, therefore, attempts to gain insights into the recent advances in scientific research and real-world applications of fungal-derived leather like materials. It makes a compelling case for this sustainable alternative and discusses the morphology-property relationship of the fungal mycelium driving this innovation. Additionally, the current processing methods and major players in the fungal leather substitute industry are presented. The paper also brings attention to the challenges facing the full deployment of fungal leather substitutes and proposes solutions with the aim of encouraging further research and resource mobilization for the acceptance of this renewable leather substitute.
Gunnera perpensa L.: A multi-use ethnomedicinal plant species in South Africa
(Taylor and Fancis, 2016) Mammo, Fitsum K.; Mohanlall, Viresh; Shode, Francis O.
Gunnera perpensa L. is a medicinal plant used in many parts of South Africa to treat several human ailments. G. perpensa is inherited from and linked to the Siswati, Changana, Sotho, Venda, Shona, Tsonga, and Zulu traditional healing systems, particularly in South African provinces where the plant species is still found in the wild. G. perpensa is declining considerably throughout its natural habitat due to over-exploitation of the plant for its medicinal uses. This review aims to gather the fragmented information on the past and present ethnomedicinal uses, phytochemistry and pharmacological properties of G. perpensa.
A logistic model for the remediation of filamentous bulking in a biological nutrient removal wastewater treatment plant
(IWA Publishing, 2015-08) Deepnarain, Nashia; Kumari, Sheena K.; Swalaha, Feroz Mahomed; Ramjith, J.; Tandoi, V.; Pillay, K.; Bux, Faizal
Biological nutrient removal (BNR) systems across the globe frequently experience bulking and foaming episodes, which present operational challenges such as poor sludge settling due to excessive filamentous bacteria. A full-scale BNR plant treating primarily domestic wastewater was monitored over a period of 1 year to investigate filamentous bacterial growth response under various plant operating parameters. Identification of filamentous bacteria by conventional microscopy and fluorescent in situ hybridisation indicated the dominance of Eikelboom Type021N, Thiothrix spp., Eikelboom Type 1851 and Eikelboom Type 0092. A cumulative logit model (CLM) was applied to elucidate significant relationships between the filamentous bacteria and plant operational parameters. The model could predict the potential abundance of dominant filamentous bacteria in relation to wastewater treatment plant operational parameters. Data obtained from the model corroborated with previous findings on the dominance of most filaments identified, except for Type 0092, which exhibited some unique traits. With further validation, the model could be successfully applied for identifying specific parameters which could contribute towards filamentous bulking, thus, providing a useful tool for regulating specific filamentous growth in full-scale wastewater treatment plants.
The prevalence of selected emerging pathogenic species in wastewater and receiving water bodies
(2022-03-16) Govender, Reshme; Stenström, Thor Axel; Pillai, Santhosh Kumar Kuttan; Swalaha, Feroz Mahomed; Bux, Faizal
Antibiotic resistance is one of the biggest threats to global health, due to the excessive use of antibiotics, among other factors. Aquatic environments are considered hotspots for antibiotic-resistant bacteria and genes due to pollution caused by various anthropogenic activities. In this study, four emerging opportunistic pathogens viz., Acinetobacter spp., Pseudomonas spp., Aeromonas spp., and Stenotrophomonas maltophilia were investigated to understand their distribution, source, and resistance patterns in wastewater and surface water. Among these, Acinetobacter baumannii and Pseudomonas aeruginosa have been listed by the World Health Organization (WHO) in 2017 as priority bacteria for further research and development. This study focused on the Umhlangane River, located in the north of Durban, in KwaZulu Natal, South Africa. The possible effect of anthropogenic activities such as discharges from wastewater treatment plants (WWTPs), hospitals, informal settlements, and veterinary clinics on the occurrence of antibiotic-resistance, and virulence signatures of the targeted organisms, was investigated. Sixty samples (12 wastewater, 48 surface water) were collected monthly (November 2016 to April 2017). This included influent and effluent of a wastewater treatment plant (WWTP) and four additional sampling sites (upstream and downstream of the WWTP, a hospital, an informal settlement, and a veterinary clinic). In addition, to the sixty samples, further samplings of aquatic plants (n=16) and sediments (n=16) were done in October 2017, specifically for the isolation of Stenotrophomonas maltophilia. The isolation and enumeration were carried out on selective media for each bacterium. The PCR positive isolates were identified using Matrix-Assisted Laser Desorption Ionization -Time of Flight Mass Spectrometry (MALDI-TOF MS) and 16S rRNA sequencing. In addition, advanced methods such as Flow Cytometry (FCM) and Droplet Digital PCR (ddPCR) were used to detect and quantify the bacteria, in comparison to conventional methods. The multiple antibiotic resistance (MAR) index was calculated to ascertain the contribution of these pollution sources to the proliferation of antibiotic-resistant bacteria in surface water. Varying counts (log10 CFU/mL) of Aeromonas spp. (2.5±0.8 to 3.3±0.4), Pseudomonas spp. (0.6±1.0 to 1.8±1.0) and Acinetobacter spp. (2.0±1.5 to 2.6±1.2) were obtained. S. maltophilia was found in the water column only at two sites and ranged from 2.7±0.3 to 4.1±1.0 log10 CFU/mL. However, it was found abundantly in the plant rhizosphere (3.6±0.1 to 4.2±0.6 log10 CFU/mL) and sediment (3.8±0.1 to 5.0±0.1 log10 CFU/mL) samples. The major Aeromonas species identified by MALDI-TOF MS was A. hydrophila / caviae (58%) whilst P. putida (51%) was common amongst the Pseudomonas isolates. The Acinetobacter genus was dominated by the Acinetobacter baumannii complex (26%), in contrast, all Stenotrophomonas maltophilia identities were confirmed via Polymerase Chain Reaction (PCR) and MALDI-TOF MS. Aeromonas (71%) and Pseudomonas (94%) isolates displayed resistance to three or more antibiotics. Aeromonas isolates displayed high resistance against ampicillin and had higher MAR indices, downstream of the hospital. The virulence gene, aer in Aeromonas was positively associated with the antibiotic resistance gene blaOXA (χ 2=6.657, p<0.05) and the antibiotic ceftazidime (χ 2=7.537, p<0.05). Pseudomonas exhibited high resistance against third-generation cephalosporins in comparison to carbapenems. Some Pseudomonas and Aeromonas isolates were extended-spectrum β-lactamase producing bacteria as the blaTEM gene was detected in Aeromonas spp. (33%) and Pseudomonas spp. (22%). All S. maltophilia isolates were resistant to the antibiotic’s trimethoprim-sulphamethoxazole, meropenem, imipenem, ampicillin, and cefixime. Acinetobacter isolates were resistant to trimethoprimsulphamethoxazole (96%) and polymyxin (86%). The genes coding for resistance against these antibiotics were detected in both S. maltophilia and Acinetobacter. Efflux pump genes were detected in all isolates of S. maltophilia. High MAR indices were observed in isolates of Pseudomonas, S. maltophilia, and Acinetobacter at the hospital site. However, Aeromonas spp. had the highest MAR in isolates from the WWTP effluents. A comparative analysis of three different methods was performed to understand their applicability and accuracy in detecting these pathogens from wastewater samples. The total viable count using the LIVE/DEAD Baclight bacterial viability kit measured an average count (log10 bacteria per mL) of 7.8±0.03 (influent) and 6.7±0.07 (effluent) using the Flow Cytometer. The total viable count using the BacLight kit was higher than the total plate count, which was 6.46±0.02 and 4.63±0.07 log10 CFU/mLfor influent and effluent, respectively. Similarly, the concentration for each of the target bacteria determined using Flow Cytometry combined with Fluorescent-In situ hybridization (Flow-FISH) method ranged from 5.41±0.07 to 5.92±0.02 (influent) and 3.43±0.2 to 4.31±0.15 (effluent) log10 bacteria per mL which was higher than the selective plate counts (3.81±0.35 to 4.17±0.1 and 3.16±0.17 to 3.7±0.20 log10 CFU/mL, for influent and effluent respectively). The ddPCR results obtained showed the highest concentration of bacteria from both influent and effluent samples in comparison to the Flow-FISH and the plate count methods, indicating the sensitivity of this method in detecting both live and dead cells. Pseudomonas was observed to be dominant and was found in the concentration of 7.19±0.24 copies per mL (influent) and 6.48±0.20 copies per mL (effluent) while S. maltophilia (influent: 5.4 ± 0.90 copies per mL effluent: 4.53±0.57 copies per mL) was detected in the lowest concentration. A similar trend was observed in comparison to the data from the plate counts, albeit at lower concentrations. This study, therefore, makes significant contributions in several areas; firstly, it shows the abundance of opportunistic, antibiotic-resistant, and virulent bacteria in wastewater and surface water within Durban. It further demonstrates that these bacteria are mainly from anthropogenic sources such as hospitals and WWTPs. Additionally, the findings indicate the potential for community-acquired infections with these bacteria, necessitating the need for risk reduction interventions aimed at reducing environmental pollution and exposure.
Undergraduate inquiry-based research to promote sustainable development goal 11 (sustainable cities and communities)
(Durban University of Technology, 2022) Govender, Indrani; Pillay, Rajendran
The global sustainability agenda provides the opportunity for higher education institutions to mainstream the Sustainable Development Goals into their programmes to contribute towards achieving these goals. Using an inquiry-based research approach, underpinned by constructivism, this study aimed to determine how research concepts and research skills can be integrated effectively into a first-year module through inquiry-based learning. First-year students at a South African university were assigned research tasks to analyse journal articles and compile a summative project based on observations in urban ecosystems. Using a mixed-methods approach, data were collected via online, structured questionnaires, reflective practice schedules and semi-structured interviews. Data were analysed quantitatively using descriptive statistics and supported by qualitative analysis of open-ended responses. Some of the findings included main skills developed, communication and social skills; main challenges experienced, finding a study site and working with a partner; the research task was relevant to career and society, and enhanced understanding of the module content. The integration of research at undergraduate level fostered environmental stewardship, positive career aspirations, motivation to pursue further research, and promoted problem-solving to real-world problems. It is recommended that universities support more undergraduate programmes to adopt inquiry-based learning within authentic research tasks.