Aspergillus flavus is the main producer of carcinogenic aflatoxins in agricultural commodities such as maize. This fungus occurs naturally on crops, and produces aflatoxins when environmental conditions are favorable. The aim of this study is to analyse the genetic variability among 109 A. flavus isolates previously recovered from maize sampled from a known aflatoxin-hotspot (Eastern region, Kenya) and the major maize-growing area in the Rift Valley (Kenya), and to determine their toxigenic potential. DNA analyses of internal transcribed spacer (ITS) regions of ribosomal DNA, partial β-tubulin gene (benA) and calmodulin gene (CaM) sequences were used. The strains were further analyzed for the presence of four aflatoxin-biosynthesis genes in relation to their capability to produce aflatoxins and other metabolites, targeting the regulatory gene aflR and the structural genes aflP, aflD, and aflQ. In addition, the metabolic profile of the fungal strains was unraveled using state-of-the-art LC-MS/MS instrumentation. The three gene-sequence data grouped the isolates into two major clades, A. minisclerotigenes and A. flavus. A. minisclerotigenes was most prevalent in Eastern Kenya, while A. flavus was common in both regions. A. parasiticus was represented by a single isolate collected from Rift Valley. Diversity existed within the A. flavus population, which formed several subclades. An inconsistency in identification of some isolates using the three markers was observed. The calmodulin gene sequences showed wider variation of polymorphisms. The aflatoxin production pattern was not consistent with the presence of aflatoxigenic genes, suggesting an inability of the primers to always detect the genes or presence of genetic mutations. Significant variation was observed in toxin profiles of the isolates. This is the first time that a profound metabolic profiling of A. flavus isolates was done in Kenya. Positive associations were evident for some metabolites, while for others no associations were found and for a few metabolite-pairs negative associations were seen. Additionally, the growth medium influenced the mycotoxin metabolite production. These results confirm the wide variation that exists among the group A. flavus and the need for more insight in clustering the group.

Unraveling the genetic diversity of livestock species is central to understanding their value and importance for conservation and improvement in diverse production environments. In developing countries, information on genetic attributes of many livestock species is unfortunately scanty to support well-informed decision-making upon relevant management strategies. This study aimed at investigating allelic variability, genetic diversity, and genetic relationships of 10 indigenous chicken ecotypes from Southern Highlands of Tanzania using the Major Histocompatibility Complex-linked LEI0258 marker. A total of 400 DNA samples, 40 per ecotype, were genotyped by capillary electrophoresis. Thirty different alleles with sizes ranging from 197 to 569 bp were determined. The number of alleles ranged from 17 (Itunduma) to 21 (Mbeya), with an average of 19.20 alleles per ecotype. Allelic polymorphism was further evaluated through genotyping by Sanger sequencing. Thirty-three DNA samples with different fragment sizes were re-amplified and their alleles sequenced to depict polymorphism based on a combination of two repeat regions at 12 and 13 bp, respectively, and flanking regions with SNP and indels. The repeat region at 13 bp appeared 1 to 28 times, whereas the region at 12 bp appeared 3 to 19 times in all sequenced fragments. The numbers of indels and SNP determined were 7 and 9, respectively. From capillary electrophoresis, the Chunya and Msimbazi ecotypes exhibited the highest genetic diversity (0.937), whereas the lowest value (0.910) was observed from the Mbarali ecotype, with an average of 0.925. The Namtumbo and Wanging’ombe ecotypes showed high inbreeding coefficients (F IS > 0.05), whereas a high excess heterozygote value (F IS = –0.098) was observed from the Njombe ecotype. Two percent of the genetic diversity was due to differences among ecotypes, and the rest was due to differences among individuals within the ecotypes. Despite the overall low genetic differentiation, both fragment and sequencing analyses depicted a high allelic and genetic variability across 10 chicken ecotypes. These results therefore, underscore the importance of establishing appropriate conservation and management strategies to capitalize on observed variability and maintain genetic flexibility across diverse production environments.

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Ethiopia is the center of origin and genetic diversity of arabica coffee. Forty-two commercial arabica coffee varieties were developed by Jimma Agricultural Research Center (JARC) of Ethiopian Institute of Agricultural Research (EIAR) and released for production under diverse agro-ecologies of the country. Information on the level of genetic diversity among these varieties is scarce. Out of the 42 varieties, the genetic diversity of 40 widely cultivated commercial varieties was assessed using 14 simple sequence repeat (SSR) markers. These markers revealed polymorphism among the varieties. High average number of polymorphic alleles (7.5) and polymorphic information content (PIC = 80%) per locus were detected among the varieties. The genetic similarity among varieties using the Jaccard's similarity coefficient ranged from 0.14 to 0.78, with a mean of 0.38. The range of genetic similarity coefficient values in 92% of the possible pair-wise combinations varied from 0.14 to 0.50, indicating the presence of distant genetic relatedness among the varieties. Unweighted pair group method using arithmetic mean (UPGMA) clustering showed six major clusters and three singletons. Coffee varieties, belonging to the same geographic origin, were distributed across clusters. This study represents the first evidence of the presence of a high level of genetic diversity in Ethiopian commercial arabica coffee varieties. Divergent varieties with complementing traits could be crossed to develop productive hybrid coffee varieties.

Mango fruits are highly nutritious and economically important to Kenyan farmers, who cultivate three categories of cultivars/landraces; local small-fruited, local big-fruited and improved, introduced cultivars. The small-fruited landraces are said to be well adapted to the local environment but are being replaced by introduced cultivars before their diversity has been documented. This study aimed at assessing morphological and genetic diversity of 36 local mango landraces from 35 randomly selected farms in Eastern Kenya. Fruits were collected from three locations for morphological characterization using the 'Descriptors for Mango' of the International Plant Genetic Resources Institute. Leaves of the same accessions were sampled for genetic diversity assessment using microsatellites. Morphological characterization showed that mean fruit length was 5.6-12.5 cm, while mean fruit weight was 93-578 g. Fruit shape was mostly 'roundish' , while fruit ground colour 'green'. Hierarchical cluster analysis with seven discriminant morphological variables resulted in four clusters. Analysis of molecular variance (AMOVA) indicated that variation was high (97%) among, but low (3%) within groups. Phylogenetic analysis using Neighbor Joining method resulted in three clusters that lacked consistency with the morphological clusters. Findings from this study may assist to select superior local mango accessions for future breeding programmes and to develop 'conservation through use' strategies for Kenyan local mangoes to retain their valuable genetic resources.

The stearoyl-CoA desaturase 1 (SCD1) A293V and acyl CoA: diacylglycerol acyltransferase 1 (DGAT1) K232A polymorphisms have been associated with significant variation in bovine milk fatty acid composition and unsaturation indices in western cattle breeds. This study aimed to estimate the milk fatty acid variability in indigenous Borgou and White Fulani cattle breeds of Benin, and the effects of the SCD1 A293V and DGAT1 K232A polymorphisms on milk and fatty acid composition and unsaturation indices. Thus, 85 Borgou and 96 White Fulani cows were genotyped for the SCD1 A293V and DGAT1 K232A polymorphisms and their milk and fatty acid composition and unsaturation indices were determined. Borgou presented milk with higher linoleic acid (P < 0.001), oleic acid (P < 0.05), C18 index (P < 0.001), total unsaturation index (P < 0.05), and lower total saturated fatty acid (SFA) compared to White Fulani. The SCD1 VV genotype was associated with higher protein and lactose contents in White Fulani (P < 0.05). In Borgou, the SCD1 AV genotype was associated with higher C14 and total unsaturation indices (P < 0.01), while the SCD1 V allele was associated with decrease in C14 index (P < 0.05). In White Fulani, the SCD1 VV genotype was associated with lower C18:1 cis-9 content (P < 0.05) while the DGAT1 K allele was associated with increased total SFA (P < 0.05), and decreased C18 index (P < 0.05), total unsaturation index (P < 0.01) and total monounsaturated fatty acid (P < 0.01). The SCD1 A293V and DGAT1 K232A may serve as genetic markers to improve milk fatty acid traits in Borgou and White Fulani breeds.Electronic supplementary materialThe online version of this article (10.1007/s11033-018-4331-4) contains supplementary material, which is available to authorized users.

BackgroundTea (Camellia sinensis) infusions are widely consumed beverages with numerous health benefits. However, physiological and molecular responses mediating these activities are poorly understood.MethodThree replicates of 4TI cancer cell suspension (2.0 × 105 cells/ml) were challenged in vitro with various concentrations of green, black and purple tea infusions to asseses their cytoxicity and associated differentially expressed genes in the cells. Inhibitory activity was tested by using serial dilutions of respective tea infusions in a 96 well ELISA plate.ResultsGreen tea had the highest inhibition on 4TI cells proliferation at a concentration of IC50 = 13.12 μg/ml. Further analysis of the 4TI cancer cell line treated with tea using 454 pyrosequencing generated 425,696 reads with an input mean length of 286.54. Trimmed sequences were imported on a CLC genomic workbench v7.03 and annotated on a reference mouse genome (Mus musculus strain C57BL/6 J). Results revealed a differential expression of apoptosis related genes in the transcriptome. Casp8, Casp9, Casp3, Casp6, Casp8AP2, Aifm1, Aifm2 and Apopt1 genes were significantly upregulated indicating the process of apoptosis was initiated and executed.ConclusionThese findings on caspases offer valuable information on the mechanism of tea as an anticancer agent and will contribute to further research in future novel treatments.

The Tanzanian goat (Capra hircus) population is currently estimated to be 24.1 million (NBS, 2020) with 97% comprising of indigenous goats belonging to the Small East African (SEA) goat breed (MLF, 2017). Due to their adaptability to different climatic conditions, the indigenous goats are widely distributed in almost all agro-ecological zones of Tanzania. Goats are important species for the livelihood of the rural farming communities especially those residing in arid and semi-arid areas of Tanzania where other agricultural activities are