Early bacterial biofilm colonizers in the coastal waters of Mauritius

Background: The past years have witnessed a growing number of researches in biofilm forming communities due to their environmental and maritime industrial implications. To gain a better understanding of the early bacterial biofilm community, microfiber nets were used as artificial substrates and incubated for a period of 24 h in Mauritian coastal waters. Next-generation sequencing technologies were employed as a tool for identification of early bacterial communities. Different genes associated with quorum sensing and cell motility were further investigated. Results: Proteobacteria were identified as the predominant bacterial microorganisms in the biofilm within the 24 h incubation, of which members affiliated to Gammaproteobacteria, Alphaproteobacteria and Betaproteobacteria were among the most abundant classes. The biofilm community patterns were also driven by phyla such as Firmicutes, Bacteroidetes, Chloroflexi, Actinobacteria and Verrucomicrobia. The functional analysis based on KEGG classification indicated high activities in carbohydrate, lipid and amino acids metabolism. Different genes encoding for luxI, lasI, agrC, flhA, cheA and cheB showed the involvement of microbial members in quorum sensing and cell motility. Conclusion: This study provides both an insight on the early bacterial biofilm forming community and the genes involved in quorum sensing and bacterial cell motility.

Jatropha curcas L:Phytochemical, antimicrobial and larvicidal properties

Objective: To evaluate antimicrobial activities as well as the phytochemical and lav-icidal properties of different parts of Jatropha curcas L. (J. curcas) growing in Mauritius. Methods: Determination of the presence of phytochemicals in the crude plants extracts by test tube reactions. Disc diffusion method and microdilution method were used to detect the antimicrobial sensitivity and activity (minimal inhibitory concentration). The crude solvent extracts were also tested on the larvae of two insects, Bactrocera zonata and Bactrocera cucurbitae (Diptera, Tephritidae). Results: The antimicrobial activities were significantly dependent for the different crude plant extracts on the thirteen microorganisms tested. For the Gram-positive bacteria, the crude ethyl acetate extract was more efficient compared to the Gram-negative bacteria with both solvents being effective. The crude ethyl acetate extract of J. curcas bark and mature seed oil showed the highest efficacy. The highest mortality percentage was observed after 24 h for both Diptera flies with (66.67 ± 2.89)%of Bactrocera cucurbitae larvae killed by ethyl acetate extract of J. curcas bark. Conclusions: This paper compared the different J. curcas plant sections with respect to the effectiveness of the plant as a potential candidate for new pharmaceuticals. The lar-vicidal effect was also studied in order to demonstrate the dual purpose of the plant.

Repetitive element palindromic PCR (rep-PCR) as a genetic tool to study interspecific diversity in Euphorbiaceae family

Background The classification of diversity in germplasm collections is important for plant breeding. The repetitive element palindromic-polymerase chain reaction (rep-PCR) technique was used to investigate inter-specific diversity within 17 species from the Euphorbiaceae family using REP and BOX primers. Results The agglomerative cluster analysis was used to evaluate the scoring data. BOX and REP gave amplification with polymorphism of 98.84% and 100% respectively. REP marker demarcated between the subgenus peltatae. Both markers confirmed Jatropha tanjorensis as a natural hybrid between Jatropha gossypifolia and Jatropha curcas. Five random sequences from the rep-PCR gels were chosen, cloned and sequenced. The blast results demonstrated that the amplified products were from the mitochondrial genomes. Conclusion The rep-PCR molecular tool can be used to characterize diversity in plants as they are suitable for distinguishing eukaryotic genomes effectively.

α-Amylase Production on Low-Cost Substrates by Naxibacter sp. Isolated from Mauritian Soils.

Alpha amylase is an important enzyme used in different industries, which degrades starch into smaller disaccharides. Extracellular α-amylase producing organisms were isolated from soil samples from Mauritius and identified by standard biochemical tests. In this study, the high yielding strain was used for amylase production. The potential of four readily available substrates, namely sugarcane bagasse, potato peel, kitchen wastes and banana peel to induce amylase production was investigated. Different parameters like temperature (30ºC, 40ºC, 50ºC, 60ºC & 70ºC), different pH (5.0, 6.0, 7.0, 8.0 & 9.0) and inoculum sizes (10%, 20%, 50%, 100% & 150% v/w) were used for the α-amylase production. It was found that α-amylase production and activity was highest for potato peel at 50ºC at pH 6.0 and inoculum size 50% (v/w). Amylase assays performed at different incubation temperatures (30ºC - 60ºC) and pH (5-9) showed that the amylase worked best at 50ºC and pH 7.Based on results of biochemical tests and 16S ribosomal RNA gene sequences, the isolate was identified to belong to the Betaproteobacteria, closely related to Naxibacter haematophilus (99% sequence similarity to the type strain).

Biotechnology in Mauritius: current status and constraints

Agriculture today faces the challenge of sustainable productivity and improved food security on a shrinking area of land under cultivation. Until recently, biotechnology has been viewed as an expensive technology affordable only by rich industrial countries. However, it is now increasingly considered as an essential tool for developing countries to tackle the numerous problems of underdevelopment. Unfortunately, to date, Mauritius, like many other countries in Africa, lags far behind in development, use and commercialisation of biotechnology. This paper outlines the current status of biotechnology in Mauritius, some important constraints faced, as well as how policy makers are planning to make Mauritius ôassume the role of a service provider and know-how disseminator in the field of biotechnology by acting as a regional hub and a regional nurseryõ.