Mapping Development of the Human Intestinal Niche at Single-Cell Resolution

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Measurement of biological aerosol with a fluorescent aerodynamic particle sizer (FLAPS): correlation of optical data with biological data

Biological aerosol measurement in real time is anurgent military requirement that also has manypotential non-military applications. Such detectioncapabilities will be useful in environmentalmonitoring, for example, in gathering information inperceived hazardous areas like housing developmentsdownwind of sewage treatment plants.Experience gained from measuring fluorescence signalsof single bacterial spores under flow cytometry usingUV excitation at 340--360 nm, was applied to concepttesting of a prototype instrument, built to do thesame for aerosols. This machine was capable ofresolving particle size as well as fluorescenceintensity of each particle under laboratory and fieldconditions; it was called the fluorescent aerodynamicparticle sizer (FLAPS). A second generation FLAPS(FLAPS2) was designed to be smaller, power efficientand field portable. FLAPS2 was challenged underrefereed conditions in blind trials to determine if itcould detect biological aerosols in natural fieldenvironment. This paper describes practical aspects ofmeasuring biological aerosols when the results must becompared to reference samplers that provide culturableor ``live' data. Treatment of particle size andfluorescence information is discussed with respect toFLAPS and reference data fidelity. Finally, anobjective method is introduced to evaluate FLAPS datacorrelation to reference data. The measurementssuggest that there is positive correlation betweenFLAPS measurements and live biological aerosolparticles.     

Methylaplysinopsin and other marine natural products affecting neurotransmission

Methylaplysinopsin is a novel marine natural product that, after oral administration, prevented the effects of tetrabenazine in mice and rats. Methylaplysinopsin was a short-acting inhibitor of monoamine oxidase activity with greatest potency when serotonin was the substrate studied. The brain concentration of serotonin in the mouse was increased by methylaplysinopsin over the same time course as monoamine oxidase inhibition ex vivo. Methylaplysinopsin was also a weak inhibitor of the neuronal uptake of [3H]serotonin and a potentiator of the K+-induced release of [3H]serotonin from prelabeled synaptosomes. The predicted potentiation of serotonergic neurotransmission was supported by initial neurophysiological studies in an identified serotonergic pathway in the central nervous system of Aplysia. Two other studies on the pharmacology of marine natural products are reviewed. The majority of polyhalogenated monoterpenes isolated from red algae had central nervous system depressant properties. The exception is plocamadiene A, which caused, in mice, a reversible spastic paresis lasting up to 72 hours after oral administration. The severe muscle spasm was antagonized by diazepam. The final study discussed is the effect of a variety of marine natural products on the synthesis, neuronal uptake, and metabolism of GABA. Their selectivity is discussed with regard to the effects on metabolic respiration, and the correlation of neurochemical and neurophysiological effects on these marine substances.     

Induction of chick embryo feather malformations by an influenza C virus

The effect of influenza C virus, strain JJ/50, on the development of chicken embryos infected at 10 or 12 days was documented by microscopic techniques, as well as by gross observations of embryos or chicks at hatching. The infected, newly hatched chicks displayed marked abnormalities in their feathering. Such abnormalities were observed neither in mock-infected embryos nor in embryos injected with virus which had been previously treated with specific influenza C virus antibody. At a microscopic level, the abnormalities apparently are a result of hypertrophy and/or hyperplasia of the developing barb and barbule cells. Further, the additional development of integumental necrotic foci was correlated with the development of relatively high viral titers (greater than 256) as measured by hemagglutination (HA). Embryos infected after 12 instead of 10 days incubation showed normal feathering at hatching. Infection at 12 days, however, was correlated with the development of relatively low viral titers (HA = 4) and limited degeneration of the respiratory epithelium. The relationship of teratogenic effects to the site of viral replication in rapidly differentiating tissue is discussed.