Phytochemicals, antioxidant and antibacterial properties of a lichen species Cladonia digitata

Antioxidant activity assessment was performed using the free radical scavenging activity of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and reducing power assay. Phytochemical screening was done using chemical tests. Antibacterial activities of Cladonia digitata were determined by a disk diffusion method at concentrations of 0, 10, 50 and 100% (v/v) against pathogenic bacteria, Eschericia coli, Clostridium perfringens and Staphylococcus aureus. Standard cotrimoxazole (10 μg/ml) was used as a positive control. C. digitata revealed the presence of alkaloids, tannins, saponins, cardiac glycosides, flavonoids, anthraquinones and steroidal terpenes. The results of antioxidant activity indicate a concentration dependent activity. C. digitata extract showed better free radical scavenging activity than ascorbic acid and quercetin. There was no significant difference (T-test, p = 0.05) in the antioxidant activity between the extract and those of ascorbic acid and quercetin as assessed by the reducing power assay. The highest antibacterial activity was 16.1 mm diameter of zone inhibition observed against Clostridium perfringens followed by 15.5 mm against Staphylococcus aureus at the concentration of 100 and 50%, respectively. The results reveal that the tested extract consisted of several bioactive compounds, significant antioxidant and antimicrobial activity. The present results scientifically authenticate the use of C. digitata in folk medicine.Keywords: Phytochemicals, antioxidant, antibacterial, Cladonia digitat

Extraction of phenolic compounds from Temnocalyx obovatus

Phenolic compounds yield in plant extracts depend on the method employed in the extraction process. In this study, we investigated systematically, a method of determination of extraction yield of antioxidant compounds from Temnocalyx obovatus. A sample treatment and preparation protocol that employs strict statistical treatment to ensure sample homogeneity was applied. As preliminary indicator of homogeneity, total nitrogen and phosphorus were determined and an iterative process using Levene test was applied to statistically test the homogeneity of the ground T. obovatus leaves. At p = 0.01, homogeneity of the plant material was achieved on the third ground sample. Among the six solvents used, methanol gave the best yield of extractable phytochemicals and a butylated hydroxytoluene-spike recovery of 77%, whereas diethyl ether gave the lowest yield and a butylated hydroxytoluene-spike recovery of 63%, suggesting that optimal yields tended to be favoured by more polar solvents.Key words: Phenolic compound, antioxidant, Temnocalyx obovatus, homogeneity, Levene test, extraction yield

A comprehensive analysis of the genetic diversity and environmental adaptability in worldwide Merino and Merino-derived sheep breeds

BACKGROUND: To enhance and extend the knowledge about the global historical and phylogenetic relationships between Merino and Merino-derived breeds, 19 populations were genotyped with the OvineSNP50 BeadChip specifically for this study, while an additional 23 populations from the publicly available genotypes were retrieved. Three complementary statistical tests, Rsb (extended haplotype homozygosity between-populations), XP-EHH (cross-population extended haplotype homozygosity), and runs of homozygosity (ROH) islands were applied to identify genomic variants with potential impact on the adaptability of Merino genetic type in two contrasting climate zones. RESULTS: The results indicate that a large part of the Merino's genetic relatedness and admixture patterns are explained by their genetic background and/or geographic origin, followed by local admixture. Multi-dimensional scaling, Neighbor-Net, Admixture, and TREEMIX analyses consistently provided evidence of the role of Australian, Rambouillet and German strains in the extensive gene introgression into the other Merino and Merino-derived breeds. The close relationship between Iberian Merinos and other South-western European breeds is consistent with the Iberian origin of the Merino genetic type, with traces from previous contributions of other Mediterranean stocks. Using Rsb and XP-EHH approaches, signatures of selection were detected spanning four genomic regions located on Ovis aries chromosomes (OAR) 1, 6 and 16, whereas two genomic regions on OAR6, that partially overlapped with the previous ones, were highlighted by ROH islands. Overall, the three approaches identified 106 candidate genes putatively under selection. Among them, genes related to immune response were identified via the gene interaction network. In addition, several candidate genes were found, such as LEKR1, LCORL, GHR, RBPJ, BMPR1B, PPARGC1A, and PRKAA1, related to morphological, growth and reproductive traits, adaptive thermogenesis, and hypoxia responses. CONCLUSIONS: To the best of our knowledge, this is the first comprehensive dataset that includes most of the Merino and Merino-derived sheep breeds raised in different regions of the world. The results provide an in-depth picture of the genetic makeup of the current Merino and Merino-derived breeds, highlighting the possible selection pressures associated with the combined effect of anthropic and environmental factors. The study underlines the importance of Merino genetic types as invaluable resources of possible adaptive diversity in the context of the occurring climate changes

Characterization of microbial degradation of oxytetracycline in river water and sediment using reversed phase high performance liquid chromatography

The fate of oxytetracycline (OTC) in river water and sediment and control experiments was investigated. A high-performance liquid chromatography (HPLC) separation and identification method was used to separate, identify and quantify OTC and its major degradation products. Minimum degradation of OTC was observed in control experiments. Non microbial degradation observed up to day 26 contributed slightly above 20% of the degradation in exposed distilled water experiment. Increase in degradation of OTC after day 26 for both the covered and exposed distilled water experiments were attributed to microbial degradation due to contamination through the openings left in the set ups. Microbial degradation was observed in the river water and sediment experiment and two major degradation products were identified: 4-epi-oxytetracycline (4-epi-OTC) and β-apo-oxytetracycline (β-apo-OTC). β-apo-OTC was found to be the most stable degradation product as compared to the other main degradation products 4-epi-oxytetracycline (4-epi-OTC) and α-apo-oxytetracycline, (α-apo-OTC). The present results have shown that microbial degradation plays a major role in the removal of OTC in natural environments.  Key words: Oxytetracycline, microbial degradation, rephrased phase HPLC, river water and sedimen

Chemical profiling of antifungal Dicerocaryum senecioides and Diospyros mespiliformis extracts using TLC-p-iodonitrotetrazolium violet assay and GC–MS/MS

Abstract Background Despite the availability of conventional medication for fungal skin diseases, dermatophytic infections are now a major crisis in the whole world due to multidrug resistance. In an effort to search for complementary and alternative remedies, this study evaluated the chemical composition of Dicerocaryum senecioides and Diospyros mespiliformis leaf and fruit extracts, respectively, exhibiting significant in vitro antifungal activity. Ethyl acetate extracts of each plant were screened for antifungal activity against three fungi species: Candida albicans, Trichophyton rubrum and Epidermophyton floccosum using disc diffusion and poisoned food assays. Gas chromatography–tandem mass spectrometry (GC–MS/MS) was used to evaluate the chemical composition after isolation of active bands by thin-layer chromatography-p-iodonitrotetrazolium chloride assay. Results The composite crude ethyl acetate extracts of D. mespiliformis and D. senecioides (1:1) exhibited concentration-dependent antifungal potencies. C. albicans was susceptible to the crude extracts up to a minimum concentration of 6.25%. E. floccosum and T. rubrum were more susceptible up to a minimum extract concentrations of 1%. GC–MS/MS analysis of the isolated active TLC bands revealed bioactive compounds including flavonoids (quercetin, luteolin), together with their O-glycosylated counter parts and the C-monoglycosylated flavonoids (vitexin, orientin, isovitexin and isoorientin), terpenoids, esters and other phenolic acids. Some of the compounds were common to both plants. Conclusion The findings of this study show that D. senecioides and D. mespiliformis extracts consist of important bioactive compounds to warrant their use in complementary and alternative poly-herbal formulations against fungal infections

Potential Devastating Domino Effect: A Case Study of Msasa Industrial Area, Zimbabwe

Aims: To assess the likelihood of occurrence of domino effect in a group of neighbouring companies in Msasa Industrial area. Study Design: A case study approach was used. Place and Duration of Study: Msasa industrial area, Harare Zimbabwe between June 2011 and June 2012. Methodology: Information was sought through interviews, questionnaires and observations from 15 companies in Msasa. The What If Analysis (WIA) was also used to postulate the potential upsets that may result in accidents. A semi qualitative approximate domino effect analysis procedure was used to simulate the likely sequence of an event after its initiation. Discussion: In the cluster, domino effect was most likely to be initiated and propagated by fires (pool, flash, fireballs or jet), explosions (confined vapour cloud explosions (CVCE), boiling liquid expanding vapour explosions (BLEVE), vented explosions, vapour cloud explosions, and dust explosions) and toxic release with effects ranging from being catastrophic, critical, marginal or negligible. It was found that there has been no domino risk analysis and hence was a strong possibility of destruction of the entire industrial area and neighbouring residential areas in the case of the forecast domino accidents. Toxic and dust releases were most likely to contaminate neighbouring residence leading to exposed toxic substance for long periods after the release. Conclusion: Msasa industrial area may pose a serious domino effect risk, hence the need to make it mandatory for domino effect analysis studies in industrial areas and sharing safety information with neighbouring companies and communities

Improving oxidative stability of soya and sunflower oil using Temnocalyx obovatus extracts

Recently an increasing interest in formulations of medicinal plant origin and other plant additives as antioxidants has been observed in the food market and pharmaceutical fields. This is as a result of the realization that synthetic antioxidants can participate as mutagenic and genotoxic agents. In this study Temnocalyx obovatus extracts were compared with rosemary (Rosmarinus officinallis) and tert- butyl-hydroquinone (TBHQ) as possible antioxidants in sunflower and soya oil. Upon addition of 200 ppm of dried leaf extract, acetone extract yielded protection of the samples against oxidation more efficiently as compared to rosemary, ethanol, methanol and TBHQ extracts added at the same concentration for both peroxide value determinations and Rancimat method. Higher induction periods, 12.45 and 17.17 h were achieved with acetone extracts. Increasing the concentration from 50 to 200 ppm increased the antioxidant effect of the extracts. On analyzing ultra-violet (UV) absorption at 232 nm, acetone extract showed the least absorbance implying greater protection against oil oxidation. Results of the present study are interesting as they may lead to isolation and identification of bioactive compounds present in T. obovatus that can be used to prolong shelf lives in oil based foods which are susceptible to rancidification.Key words: Oxidative stability, Temnocalyx obovatus, peroxidation, antioxidant

Heavy Metal Content in Acacia saligna and Acacia polyacantha on Slime Dams: Implications for Phytoremediation

Aims: To determine heavy metal content in A. saligna and A. polyacantha so as to ascertain their possible use in phytoremediation Place and Duration of Study: Bindura University of Science Education, Chemistry and Biological Sciences Dept, P. Bag 1020, Bindura, Zimbabwe. The study was carried out between December 2011 and January 2013. Methodology: Two sites which are the slime dams at a local gold mine in Bindura and a control site 10km outside the slimes were used in the study. A total of four sampling points each in the form of 5x5m quadrants were established after every 100m in transects, 700m long separately established on the control and slime dams. Soil samples at 5-10cm and 10- 15cm levels as well as roots, leaves and bark from five sampled plants were collected at each sampling point. The metals content was analyzed using Atomic Absorption Spectrometry and Inductively Coupled Plasma. The bioaccumulation factor and the shoot/root quotient were computed in Microsoft excel. Analysis of Variance was carried out using SPSS and Genstat Version 16. Results: The present study shows that A. saligna and A. polyacantha accumulate heavy metals with biological accumulation factor (BAF) value results indicating significant differences between the slimes and control sites. Both species had BAF values for nickel, copper and iron greater than one except for zinc, lead and arsenic. The shoot/root quotients showed that nickel, copper and iron are translocated to the shoots in the species as compared to zinc, lead and arsenic. Conclusion: A. saligna and A. polyacantha showed evidence of accumulation of nickel, copper and iron and therefore may be used for phytoremediation and restoration purposes at mine slime dams

Current address: Discipline of Genetics

________________________________________________________________________________ Abstract Genetic evaluation of dairy cattle using test-day models is now common internationally. In South Africa a fixed regression test-day model is used to generate breeding values for dairy animals on a routine basis. The model is, however, often criticized for erroneously assuming a standard lactation curve for cows in similar contemporary groups and homogeneity of additive genetic variances across lactation and for its inability to account for persistency of lactation. The random regression test-day model has been suggested as a more appropriate method and is currently implemented by several Interbull member-countries. This review traces the development of random regression methods and their adoption in test-day models. Comparisons are drawn with the fixed regression test-day model. The paper discusses reasons for suggesting the adoption of the random regression approach for dairy cattle evaluation in South Africa and identifies the key areas where research efforts should focus. _______________________________________________________________________________

Table1_Selection signature analysis and genome-wide divergence of South African Merino breeds from their founders.XLSX

Merino sheep are a breed of choice across the world, popularly kept for their wool and mutton value. They are often reared as a pure breed or used in crossbreeding and are a common component in synthetic breed development. This study evaluated genetic diversity, population structure, and breed divergence in 279 animals of Merino and Merino-based sheep breeds in South Africa using the Illumina Ovine SNP 50K BeadChip. The sheep breeds analysed included the three Merino-derived breeds of Dohne Merino (n = 50); Meatmaster (n = 47); and Afrino (n = 52) and five presumed ancestral populations of Merinos (Merino (n = 46); South African Merino (n = 10); and South African Mutton Merino (n = 8)); and the non-Merino founding breeds of Damara (n = 20); Ronderib Afrikaner (n = 17); and Nguni (n = 29). Highest genetic diversity values were observed in the Dohne Merino (DM), with Ho = 0.39 ± 0.01, followed by the Meatmaster and South African Merino (SAM), with Ho = 0.37 ± 0.03. The level of inbreeding ranged from 0.0 ± 0.02 (DM) to 0.27 ± 0.05 (Nguni). Analysis of molecular variance (AMOVA) showed high within-population variance (>80%) across all population categories. The first principal component (PC1) separated the Merino, South African Mutton Merino (SAMM), DM, and Afrino (AFR) from the Meatmaster, Damara, Nguni, and Ronderib Afrikaner (RDA). PC2 aligned each Merino-derived breed with its presumed ancestors and separated the SAMM from the Merino and SAM. The iHS analysis yielded selection sweeps across the AFR (12 sweeps), Meatmaster (four sweeps), and DM (29 sweeps). Hair/wool trait genes such as FGF12; metabolic genes of ICA1, NXPH1, and GPR171; and immune response genes of IL22, IL26, IFNAR1, and IL10RB were reported. Other genes include HMGA, which was observed as selection signatures in other populations; WNT5A, important in the development of the skeleton and mammary glands; ANTXR2, associated with adaptation to variation in climatic conditions; and BMP2, which has been reported as strongly selected in both fat-tailed and thin-tailed sheep. The DM vs. SAMM shared all six sweep regions on chromosomes 1, 10, and 11 with AFR vs. SAMM. Genes such as FGF12 on OAR 1:191.3–194.7 Mb and MAP2K4 on OAR 11:28.6–31.3 Mb were observed. The selection sweep on chromosome 10 region 28.6–30.3 Mb harbouring the RXFP2 for polledness was shared between the DM vs. Merino, the Meatmaster vs. Merino, and the Meatmaster vs. Nguni. The DM vs. Merino and the Meatmaster vs. Merino also shared an Rsb-based selection sweep on chromosome 1 region 268.5–269.9 Mb associated with the Calpain gene, CAPN7. The study demonstrated some genetic similarities between the Merino and Merino-derived breeds emanating from common founding populations and some divergence driven by breed-specific selection goals. Overall, information regarding the evolution of these composite breeds from their founding population will guide future breed improvement programs and management and conservation efforts.</p