Linking growing conditions to stable isotope ratios and elemental compositions of Costa Rican bananas (Musa spp.).

Traceability of agricultural produce is getting increasingly important for numerous reasons including marketing, certification, and food safety. Globally, banana (Musa spp.) with its high nutritional value and easy accessibility, is a popular fruit among consumers. Bananas are produced throughout the (sub-)tropics under a wide range of environmental conditions. Environmental conditions could influence the composition of bananas. Understanding the effect of these conditions on fruit composition provides a way of increasing the fruit's traceability and linking it to its origin - a crucial aspect for the increasing global supply chain. In this study, we examined the influence of growing conditions on the isotopic and elemental composition of bananas produced in 15 Costa Rican farms. A total of 88 bananas (peel and pulp) were collected from the farms and analysed for isotopic signatures (δ13C, δ15N, and δ18O) and elemental compositions. The growing conditions were characterized in terms of climate, topography and soil conditions. The isotopic ratios differed significantly between groups of farms. The δ13C and δ15N values were mainly influenced by soil types, while rainfall and temperatures related more to the δ18O values. The elemental compositions of the bananas were primarily influenced by the local rainfall and soil types, while the geographical origin could be distinguished using principal component analysis. The overall results link the growing conditions to the isotopic and elemental compositions of bananas, thereby also providing a way to trace its origin.

[Construction of conjugal transfer system of Streptomyces venezuelae var. Qinlingensis and the expression of vitreoscilla hemoglobin].

OBJECTIVE: To Construct of conjugal transfer system of Streptomyces venezuelae var. Qinlingensis and express of vitreoscilla hemoglobin. METHODS: Intergeneric genetic transfer system was based upon plasmid pSET152 and pHZ1358 from Donor E. coli ET12567 (pUZ8002) to Streptomyces venezuelae var. Qinlingensis. RESULTS: Our data showed that Intergeneric genetic transfer system was demonstrated and optimized. Integrating plasmid pJD100 containing Perm E and construction gene of vhb, constructed by SOE-PCR, was transformed to ET12567 (pUZ8002), and then transfered to Streptomyces venezuelae var. Qinlingensis by conjugation. The integrating expression of vhb gene in Streptomyces venezuelae var. Qinlingensis was verified by PCR and CO binding diference spectrum. CONCLUSION: In summary, intergeneric genetic transfer system was demonstrated and optimized, and this is the first report to express vhb gene in Streptomyces venezuelae var. Qinlingensis.

Early diagnosis of ataxia-telangiectasia using radiosensitivity testing.

OBJECTIVES: To utilize radiosensitivity testing to improve early diagnosis of patients with ataxia-telangiectasia (A-T). STUDY DESIGN: We established normal ranges for the colony survival assay (CSA) by testing cells from 104 patients with typical A-T, 29 phenotypic normal patients, and 19 A-T heterozygotes. We also analyzed 61 samples from patients suspected of having A-T and 25 patients with related disorders to compare the CSA with other criteria in the diagnosis of A-T. RESULTS: When cells were irradiated with 1.0 Gy, the mean survival fraction (microSF +/- 1 SD) for patients with A-T was 13.1% +/- 7.2% compared with 50.1% +/- 13.5% for healthy control patients. These data served to define a diagnostic range for the CSA (ie, <21%), a normal range (>36%), and a nondiagnostic intermediate range of 21% to 36%. The mutations of patients with A-T with intermediate radiosensitivity tended to cluster around the functional domains of the ATM gene. CONCLUSIONS: The CSA is a useful adjunctive test for confirming an early clinical diagnosis of A-T. However, CSA is also abnormal in other chromosomal instability and immunodeficiency disorders.