ARTICLE | doi:10.20944/preprints202012.0623.v1
Subject: Life Sciences, Biochemistry Keywords: Antimicrobial; berries; cytotoxic; cyanidine; elderberry; lyophilization
Online: 24 December 2020 (13:26:39 CET)
Natural phytochemicals in foods, including anthocyanins, can play an important role in human health. Anthocyanins have been reported to cause many various useful effects, such as reducing cancer cell proliferation, regulating blood pressure, preventing tumour formation, improving eyesight, and preventing diabetes. In this study, we aimed to reveal the qualitative anthocyanin content, antiproliferative and antimicrobial effects of different extracts derived from Vaccinium myrtillus, V. corymbosum, Sambucus nigra and Aronia melanocarpa. The anthocyanin content of the plants mentioned in the study was characterized after the freeze-drying process. MTT assay was used to determine the antiproliferative effect of extracts on cancer cells. Antimicrobial effects of extracts were studied on typical and clinical strains of 5 different bacteria. As a result, the anthocyanin content in the extracts obtained was determined to be quite good with the freeze-drying method, and it was also determined that the extracts had various levels of antiproliferative and antibacterial effects.
ARTICLE | doi:10.20944/preprints202112.0127.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: plant pathogenic bacterium; phage; bacterial wilt; biological control; lyophilization
Online: 8 December 2021 (14:12:11 CET)
Ralstonia solanacearum is a pathogen that causes bacterial wilt producing severe damage in staple solanaceous crops. Traditional control has low efficacy and/or environmental impact. Recently, the bases of a new biotechnological method by lytic bacteriophages vRsoP-WF2, vRsoP-WM2 and vRsoP-WR2 with specific activity against R. solanacearum were established. However, some aspects remain unknown, such as the survival and maintenance of the lytic activity after submission to a preservation method as the lyophilization. To this end, viability and stability of lyophilized vRsoP-WF2, vRsoP-WM2 and vRsoP-WR2 and their capacity for bacterial wilt biocontrol have been determined against one pathogenic Spanish reference strain of R. solanacearum in susceptible tomato plants in different conditions and making use of various cryoprotectants. The assays carried out have shown satisfactory results with respect to the viability and stability of the bacteriophages after the lyophilization process, maintaining high titres throughout the experimental period, also with respect to the capacity of the bacteriophages for the biological control of bacterial wilt, controlling this disease in more than 50% of the plants. The results offer good prospects for the use of lyophilization as a conservation method for the lytic bacteriophages of R. solanacearum in view of their commercialization as biocontrol agents.
SHORT NOTE | doi:10.20944/preprints201804.0170.v1
Subject: Life Sciences, Other Keywords: Wuchereria bancrofti antigen, lyophilization, dried blood spots, freeze-drying
Online: 12 April 2018 (16:18:09 CEST)
Antigen-based rapid diagnostic tests for Lymphatic filariasis do not come with quality control (QC) materials, and research and disease control programmes rely on stored positive plasma samples. This study was undertaken to evaluate the use of freeze-dried Wuchereria bancrofti antigen positive plasma samples to serve as QC materials for LF RDTs. 10 well characterized W. bancrofti positive samples were lyophilized and stored at 4°C, 28°C and 40°C. The samples were evaluated using the Filaria Test Strips before lyophilization and after one and three (3) months of storage. The sensitivity and stability of the lyophilized samples were evaluated. The results revealed a loss of sensitivity and stability with increasing temperature and duration of storage. The results are further discussed in terms of the use of Dried Blood Spot (DBS) in diagnostics studies on LF requiring quantitative assessments, and the need for thoughtful DBS preparation and storage.