Development of a rapid capture-cum-detection method for Escherichia coli O157 from apple juice comprising nano-immunomagnetic separation in tandem with surface enhanced Raman scattering.

A combined capture and detection method comprising of nano-immunomagnetic separation (NIMS) and surface enhanced Raman spectroscopy (SERS) was developed to detect Escherichia coli O157 from liquid media including apple juice. The capture antibodies (cAbs) were immobilized on magnetite-gold (Fe3O4/Au) magnetic nanoparticles (MNPs) which were used for separation and concentration of the E. coli O157 cells from model liquid food matrix. The capture efficiency (CE) for E. coli O157 using MNP was found to be approximately 84-94%. No cross reactivity was observed with background non-target organisms. There was a significant difference in the mean CE of bacteria captured by MNP and commercially sourced immunomagnetic microbeads (p<0.05). For the detection of target pathogen, SERS labels were prepared by conjugating gold nanoparticles with Raman reporter molecules and the detector antibody (dAb). Au-Raman label-dAb was interacted with gold coated MNP-cAb-E. coli O157 complex. The ability of this immunoassay to detect E. coli O157 in apple juice was investigated. We have successfully applied the synthesized Fe3O4/Au nanoclusters to E. coli O157 detection in apple juice using the SERS method. The lowest detectable bacterial cell concentration in apple juice was 10(2)CFU/mL with a total analysis time of less than an hour. This method presents a convenient way of preconcentration, separation, and detection of low levels of target pathogen from liquid food matrix.

Estimating bottlenose dolphin (Tursiops truncatus) hearing thresholds from single and multiple simultaneous auditory evoked potentials.

Hearing thresholds were estimated in four bottlenose dolphins by measuring auditory evoked responses to single and multiple sinusoidal amplitude modulated tones. Subjects consisted of two males and two females with ages from 4 to 22 years. Testing was conducted in air using a "jawphone" transducer to couple sound into each subject's lower right jaw. Carrier frequencies ranged from 10 to 160 kHz in one-half octave steps. Amplitude modulated stimuli were presented individually and as the sum of four, five, and nine simultaneous tones with unique carrier and modulation frequencies. Evoked potentials were noninvasively recorded using surface electrodes embedded in silicon suction cups. The presence or absence of an evoked response at each modulation frequency was assessed by calculating the magnitude-squared coherence from the frequency spectra of the recorded sweeps. All subjects exhibited traditional "U-shaped" audiograms with upper cutoff frequencies above 113 kHz. The time required for threshold estimates ranged from 23 to 37 min for single stimuli to 5-9 min for nine simultaneous stimuli. Agreement between thresholds estimated from single stimuli and multiple, simultaneous stimuli was generally good, indicating that multiple stimuli may be used for quick hearing assessment when time is limited.

The application of DNA micro-arrays (gene arrays) to the study of herbal medicines.

DNA micro-arrays (gene arrays) have become a popular and useful tool with which to study the effects of various agents and treatments on gene expression in cells and tissues. In theory one can simultaneously evaluate, in a single experiment, changes in gene expression (at the level of transcription) of the entire genome of the organism under study. Consequently these techniques have been used by many investigators interested in cancer research, differentiation and development, toxicology, and the effects of pharmaceuticals on cells and animals. In addition, recent studies have shown the capacity of the technique for revealing the importance of genes not previously implicated in a given response. However, relatively few attempts have been made so far to evaluate herbal medicines, although the potential to answer a number of relevant questions is there. In this review we first discuss the fundamental principles of the gene array technology, focusing on the individual steps in the process and their problems and pitfalls, and we discuss the analysis and interpretation of the data, the discipline of bio-informatics, without which meaningful evaluation of gene expression changes would be impossible. We next analyze specific studies, which utilized gene array technology, aimed at evaluating the effects of certain herbal medicine formulas and bioactive ingredients in animal tissues and in cell cultures. We also include a brief description of our own evaluation of Echinacea, which we have been studying for several years, to indicate possible mechanisms of action of this herbal, and also to illustrate how the techniques, especially the bio-informatics, continue to evolve. We believe, on the basis of experience acquired by us and other investigators to date, that the technology of gene array analysis can make significant contributions to understanding how herbal medicines work, and therefore can validate their applications in medicine.

Ethnomedicinal uses of Momordicacharantia (Cucurbitaceae) in Togo and relation to its phytochemistry and biological activity.

Investigation of the traditional uses of Momordica charantia (Cucurbitaceae) in Togo (West Africa) showed that it is one of the most important local medicinal plants both for ritual and ethnomedical practices. There was a high degree of consensus (>50%) for use in the treatment of gastrointestinal and viral disease among 47 groups of village informants in the general population, while 19 traditional healers reported a larger and broader set of uses. The use by informants in Gaur and Kwa language groups was not significantly different. Lyophilized Momordica charantia extracts prepared from accessions collected in Togo showed high antiviral activity (<5 microg/ml) against Sindbis and Herpes simplex type 1 viruses and anthelmintic activity against Caenorhabditis elegans at 500 microg/ml. Presence in the leaves of the triterpene glycosides momordicins I and II follows biological activity of the plant extracts. However, momordicins were found to be anthelmintic but not antiviral. Traditional healers collected plants in dry areas where momordicin content is greater.

Bioactive constituents from Iryanthera megistophylla.

Activity-guided fractionation of the 95% ethanol extract from the stem bark of Iryanthera megistophylla led to the isolation of two new compounds, named megislignan [2,3-dimethyl-4-(4-methoxyphenyl)-6-hydroxynaphthalene] (1) and megislactone [(2R,3R,4R)-3-hydroxy-4-methyl-2-(hexacos-17-enyl)butanolide] (2), along with seven known compounds, grandinolide (3), iryantherin K (4), iryantherin L (5), cinchonain I b (6), cinchonain I a (7), procyanidin B-2 (8), and cinchonain IIa (9). The structures of the new compounds were elucidated by spectral data interpretation. Isolates were evaluated for their antibacterial, antifungal, antiviral, and antiacetylcholinesterase activities.