Estimation ofcadmium and vitamin C was performed in the blood and lens of smokers in three age groups up to a maximum age of 58, habituated to smoking a minimum of 10 beedies a day for many years, as well as those of non-smokers in the same age groups. Only nuclear cataracts with or without posterior or anterior subcapsular cataract were chosen. It was found that there was a significant accumulation of cadmium in both the blood and the lens of the smokers. Such an accumulation of cadmium might have a role in cataractogenesis in chronic smokers. In a similar experiment, with smokers and non-smokers of two age groups up to a maximum age of 40, both without cataract, increased levels of cadmium were found in the blood of smokers only, though the extent of accumulation was not as high as in chronic smokers ofhigher age groups. Vitamin C content of lens was on the lower side of normal in both chronic smokers of beedies in the two age groups and non-smokers with nuclear cataract with or without posterior and anterior subcapsular cataract, and there was no significant change brought about by smoking. Vitamin C levels in blood were towards the lower side of the normal in smokers and non-smokers with and without cataract. (BrJ Ophthalmol 1995; 79: 202-206)

A non-cellulosomal xylanase from Clostridium thermocellum, XynX, consists of a family-22 carbohydratebinding module (CBM22), a family-10 glycoside hydrolase (GH10) catalytic module, two family-9 carbohydrate-binding modules (CBM9-I and CBM9-II), and an S-layer homology (SLH) module. E. coli BL21(DE3) (pKM29), a transformant carrying xynX', produced several truncated forms of the enzyme. Among them, three major active species were purified by SDS-PAGE, activity staining, gel-slicing, and diffusion from the gel. The truncated xylanases were different from each other only in their C-terminal regions. In addition to the CBM22 and GH10 catalytic modules, XynX(1) had the CBM9-I and most of the CBM9-II, XynX(2) had the CBM9-I and about 40% of the CBM9-II, and XynX(3) had about 75% of the CBM9-I. The truncated xylanases showed higher binding capacities toward Avicel than those toward insoluble xylan. XynX(1) showed a higher affinity toward Avicel (70.5%) than XynX(2) (46.0%) and XynX(3) (42.1%); however, there were no significant differences in the affinities toward insoluble xylan. It is suggested that the CBM9 repeat, especially CBM9-II, of XynX plays a role in xylan degradation in nature by strengthening cellulose binding rather than by enhancing xylan binding.

XynX of Thermoanaerobacterium sp. [corrected] is a large, multimodular xylanase of 116 kDa. An Escherichia coli transformant carrying the entire xynX produced three active truncated xylanase species of 105, 85, and 64 kDa intracellularly. The Bacillus subtilis WB700 transformant with the xynX, a strain deficient in seven proteases including Vpr, secreted two active truncated xylanase species of 65 and 44 kDa. The B. subtilis WB800 transformant with xynX, a strain deficient in eight proteases including Vpr and WprA, secreted more active enzymes, 8.46 U ml(-1), mostly in the form of 105 and 85 kDa, than the WB700 transformant, 6.93 U ml(-1). This indicates that the additional deletion of wprA enabled the WB800 to secrete XynX in its intact form. B. subtilis WB800 produced more total enzyme activity than E. coli (1,692 ± 274 U vs. 141.9 ± 27.1 U), and, more importantly, secreted almost all the enzyme activity. The results suggest the potential use of B. subtilis WB800 as a host system for the production of large multimodular proteins.

The original version of this article unfortunately contained errors. The details are as follows:1. Title "Production of XynX, a Large Multimodular Protein of Clostridium thermocellum, by Protease-Deficient Bacillus subtilis Strains" should be changed to "Production of XynX, a Large Multimodular Protein of Thermoanaerobacterium sp., by ProteaseDeficient Bacillus subtilis Strains" 2. In Abstract line 1 st , "Clostridium thermocellum" should be changed to "Thermoanaerobacterium sp."