Genome-wide CRISPR Screens Reveal Host Factors Critical for SARS-CoV-2 Infection

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Pharmacological studies on the pulmonary vein of the horse. I. Effects of selected spasmogens.

Horses suffer from a respiratory condition, similar to human allergic asthma, that is characterized by severe dyspnea, wheezing, coughing, and mucus production. Mediator substances released during the allergic reaction may contract airways and pulmonary vasculature. Nothing is known of the effects of autacoids and other vasoactive substances on equine pulmonary vessels. Therefore, spiral strips of equine pulmonary vein were prepared in vitro and the effects of histamine (H), 5-hydroxytryptamine (5HT), bradykinin (BK), carbachol (Carb), and phenylephrine (phen) were studied. The order of contractile effectiveness for the agonists on the vein was found to be 5HT greater than H greater than Bk greater than Phen greater than Carb, although H consistently produced the greatest maximal effects. H1-receptors appeared to mediate H contractions while H2-receptors had no measurable effect. 5HT responses were mediated directly by 'D-type' smooth muscle receptors. Bk produced contractions but of a lesser magnitude than either H or 5HT. Varying degrees of tachyphylaxis were observed for each agent. alpha-Adrenergic receptor stimulation by Phen initiated low-magnitude contractions whereas Carb exhibited virtually no activity on the pulmonary vein. Contractile responses of pulmonary veins to various spasmogens may contribute to the equine asthmatic response by raising vascular hydrostatic pressure, thereby enhancing edema formation.     

Chemotactic response of wild-type and aggregation-defective mutants of Polysphondylium violaceum

Abstract. The aggregation-specific chemoattractant for Polysphondylium violaceum is N-propionyl-γ-L-glutamyl-L-ornithine-δ-lactam ethyl ester, or glorin. Wild-type amoebae allowed to develop in liquid culture acquire increased ability to respond to glorin shortly after starvation, i.e., just prior to the time they become aggregation competent. Similarly, as development proceeds, the amoebae show decreased sensitivity to folic acid, but they show almost no response to cyclic AMP at any time during their development in liquid culture. The optimum concentrations for the chemotactic response are 10^-8 M for glorin and 10^-5–10^-6 M for folic acid. A class of aggregation-defective mutants, aggA , will not aggregate in the absence of an excreted pheromone, D factor. During development in liquid culture in the presence or absence of D factor, these aggA mutants show a chemotactic response similar to that of wild-type amoebae to folic acid and glorin. However, D factor does enhance the chemotactic response of aggA mutants to glorin. In the absence of D factor, mutant amoebae will form fruiting bodies if exposed to a chemotactic gradient of either folic acid or glorin. Under these conditions, the mutant amoebae circumvent the requirement for D factor in order to develop.     

Absorption of the flavin dimers

The electronic absorption spectra of the flavomononucleotide (FMN) in aqueous solution and in glycerine-water solution with change of the dye concentration have been measured. The FMN dimer absorption spectrum, monomer absorption spectrum, dimerization constant K and molar fraction of the monomer were calculated. It was found that FMN dimerization constants in aqueous solution were K_a = 118.0 l/mol and in glycerine K_g = 20.5 l/mol. In the region of the monomer absorption band two dimer absorption bands appear, in accordance with the Kasha molecular exciton theory.