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S Merchant

Publications and source records attributed to S Merchant.

85 records · Page 5Linked to original sources
PubMedDate not supplied

Assembly of chloroplast cytochromes b and c.

The synthesis of holocytochromes in plastids is a catalyzed process. Several proteins, including plastid CcsA, Ccs1, possibly CcdA and a thioredoxin, plus at least two additional Ccs factors, are required in sub-stoichiometric amounts for the conversion of apocytochromes f and c(6) to their respective holoforms. CcsA, proposed to be a heme delivery factor, and Ccs1, an apoprotein chaperone, are speculated to interact physically in vivo. The formation of holocytochrome b(6) is a multi-step pathway in which at least four, as yet unidentified, Ccb factors are required for association of the b(H) heme. The specific requirement of reduced heme for in vitro synthesis of a cytochrome b(559)-derived holo-beta(2) suggests that cytochrome b synthesis in PSII might also be catalyzed in vivo.

Amino Acid Sequence↗
PubMedDate not supplied

Quality control in pulmonary function testing. A help or a hindrance?

The results of 120 sets of ventilatory capacity, lung volume (LV) and carbon monoxide transfer factor (TCOSB) measurements, 40 sets from each of three pulmonary function laboratories in one city, were examined retrospectively. Vital capacity (VC) was estimated by a forced expiratory manoeuvre (FVC), a relaxed expiratory manoeuvre (VCR) and an inspiratory manoeuvre (VCI) in the three different tests. Differences between VCR and FVC ranged from--88 ml to + 1 400 ml with a mean of + 47 ml. VCI differed from the largest estimate of expiratory VC by--1 800 ml to + 300 ml with a mean of--480 ml. Such differences, which were observed in all three laboratories, affect the calculations in each test and thus the final results quoted. Adequate quality control therefore requires comparison of estimates of VC not only within a test but also between tests. Although more time must be spent with some patients, technical errors and poor patient performance can be distinguished from true changes in pulmonary function, thus better enabling the clinician to assess the relationship between the results and the clinical condition of the patient.

Female↗