Action spectrum from activation spectra

The compounds are highlighted from the following viewpoints anti-HIV potency and selectivity, mechanism of action, antiviral activity spectrum, clinical or therapeutic potential, and risk of resistance development. 

And only for that (extrapolated) case, the near UV-peak of the action spectrum vanishes, from which the authors conclude that the active photoreceptor is probably carotenoid in nature (cf., Fig. 6 3). 

After clavulanic acid, the penicillanic acid derivatives (particularly the corresponding sulfone analogs) have been the subject of intense research in the -lactamase inhibitor area. From this extensive investigation, two compounds (sulbactam and tazobactam) from this class have been successfully introduced into clinical use. The penicillanic acid sulfones are /3-laclamasc inhibitors that are quite homologous to clavulanate in both their mechanism of action and in the spectrum of -lactamases susceptible to their action. The first notable success in this field was the discovery of sulbactam 7 (Fig. 7), which was reported by Pfizer chemists in 1978 and shown to possess potent inhibitory activity, principally for class A //-lactamases. It had greater affinity for class C types than clavulanate. From careful comparison of its structure to clavulanate, a rational basis for the similarities between the two is apparent. Both lack a C-6 substituent. Since the absence (or presence) of this substituent is an important, but not exclusive, factor in //-lactamase recogni-... 

Mechanism of Action Piperacillin inhibits cell wall synthesis by binding to bacterial cell membranes. Tazobactam inactivates bacterial beta-lactamase. Therapeutic Effect Piperacillin is bactericidal in susceptible organisms. Tazobactam protects piperacillin from enzymatic degradation, extends its spectrum of activity, and prevents bacterial overgrowth. 

Cheng and coworkers have examined the photodissociation spectroscopy of MgCH4 in detail . The photofragmentation action spectrum has a broad featureless continuum ranging from 310 to 342 nm, with a maximum at 325 nm. In this region the channels observed are nonreactive (equation 36, ca 60%), H abstraction (equation 37, ca 1%) and CH3 abstraction (equation 38, ca 33%). Recent theoretical calculations on the C—H bond activation in MgCH4+ reveal that the formation of the insertion intermediate, CH3MgH, proceeds via a three-centered transition state . ... 

Research of recent years has moved bioflavonoids from a consideration of their effects on capillaries into a more central position in human health. Certain bioflavonoids intervene at the molecular level to potentiate or inhibit enzyme action or at the physiological level to affect rheology of blood. The broad spectrum of activity demonstrated by some of these meth-oxylated flavones appears to be directed towards processes which underlie degenerative diseases, at present our greatest killers. 

The activity spectrum of ergometrine (Fig. 7b) is quite different from that of ergotamine (Fig. 7a). It exerts a marked uterotonic effect, whereas its adrenolytic action is practically insignificant and the central nervous effects are only manifest after high doses. Ergometrine is therefore used mainly in obstetrics. In recent years it has been demonstrated that ergometrine exerts a pronounced antiserotonin effect. 

Chemiluminescence is also shown with a few simple mineral compounds. Otto (21) expressed the opinion that, if ozone causes a luminescence in the presence of water, it acts upon impurities therein. Hydrogen sulfide gives rise to an ultraviolet chemiluminescence with ozone (Zabiezynski and Orlowski, 33). Several oxygen compounds of nitrogen, especially nitric oxide, show, under the action of ozone, a spectrum different from that of active nitrogen [Morren (20), Sarrasin (23), Strutt (26), Knauss and Murrey (17) ]. Solid phosphorus trixode becomes luminescent [Thorpe and Tutton (29)]] and so do carbon monoxide, carbonyl sulfide, and carbonyl chloride at 200 C. The first of these furnishes a band spectrum of 4000 to 5000 A. which corresponds to a bimolecular process [Trautz and Seidel (31) and Trautz and Haller (30)]. Siloxane too shows oxyluminescence [Kautsky and Zocher (16)] under the influence of ozone. 

Beta-lactam antibiotics act on enzymes called penicillin-binding proteins (PBP) near the bacterial cell wall. When beta-lactam antibiotics bind covalently and irreversibly to the PBP, they interfere with the production of cell-wall peptidoglycans, causing cell lysis in hypoosmotic environments. Differences in the spectrum of activity and actions of beta-lactam antibiotics result from their relative affinity for different PBP. 

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