Search

A nucleic acid sequence-based amplification (NASBA) assay in combination with a molecular beacon was developed for the real-time detection and quantification of hepatitis A virus (HAV). A 202-bp, highly conserved 5' noncoding region of HAV was targeted. The sensitivity of the real-time NASBA assay was tested with 10-fold dilutions of viral RNA, and a detection limit of 1 PFU was obtained. The specificity of the assay was demonstrated by testing with other environmental pathogens and indicator microorganisms, with only HAV positively identified. When combined with immunomagnetic separation, the NASBA assay successfully detected as few as 10 PFU from seeded lake water samples. Due to its isothermal nature, its speed, and its similar sensitivity compared to the real-time RT-PCR assay, this newly reported real-time NASBA method will have broad applications for the rapid detection of HAV in contaminated food or water.

In a search for promising antibacterial and antifungal compounds, two new series of 2, 3-bis(5-alkyl-2-thiono-1, 3, 5-thiadiazin-3-yl)propionic acid 1 and their corresponding N, N-dimethylpropionamide 6 have been synthesized. The reaction of 2, 3-diaminopropionate 3, carbon disulfide, formaldehyde, and the appropriate alkyl amines furnished the title compound 1. N, N-dimethylpropionamides 6 were obtained by the reaction of 1 with dimethyl amine in the presence of POCl(3). The newly prepared compounds were screened in vitro against certain strains of Gram-positive and Gram-negative bacteria and compared with nalidixic acid and ciprofloxacin. Moreover, the title compounds were tested for their antifungal activity in vitro against Candida albicans, phytopathogenic, Penicillum expansum and Trichoderma hazianum, and aflatoxin-producing Aspergillus flavus. These compounds exhibit varied activity against the tested pathogenic bacteria and remarkable inhibitory effects on growth or sporulation of some of the tested fungal species.

In this study, a molecular-beacon-based real-time reverse transcription (RT)-PCR assay was developed to detect the presence of hepatitis A virus (HAV) in environmental samples. A 125-bp, highly conserved 5' noncoding region of HAV was targeted. The sensitivity of the real-time RT-PCR assay was tested with 10-fold dilutions of viral RNA, and a detection limit of 1 PFU was obtained. The specificity of the assay was demonstrated by testing with other environmental pathogens and indicator microorganisms, and only HAV was positively identified. When combined with immunomagnetic separation, the real-time RT-PCR assay successfully detected as few as 20 PFU in seeded groundwater samples. Because of its simplicity and specificity, this assay has broad applications for the rapid detection of HAV in contaminated foods or water.