Environmental factors and Parkinson's disease: a case-control study in China

We studied the role of environment in the development of Parkinson's disease (PD) in China, where industrialization is relatively recent and the population geographically stable. Using a case-control method, we investigated the relationship between PD and exposure to the following factors before disease onset: place of residence, source of drinking water, environmental and occupational exposure to various agricultural and industrial processes. Occupational or residential exposure to industrial chemicals, printing plants, or quarries was associated with an increased risk of developing PD. In contrast, living in villages and exposure to the common accompaniments of village life, wheat growing and pig raising, were associated with a decreased risk for PD. PD cases and controls did not differ with respect to other factors investigated. These findings are consistent with the hypothesis that environmental exposure to certain industrial chemicals may be related to the development of PD.

Phenylalanine ammonia-lyase gene organization and structure

Phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) genomic sequences were isolated from bean (Phaseolus vulgaris L.) genomic libraries using elicitor-induced bean PAL cDNA sequences as a probe. Southern blot hybridization of genomic DNA fragments revealed three divergent classes of PAL genes in the bean genome. Polymorphic forms were observed within each class. The nucleotide sequences of two PAL genes, gPAL2 (class II) and gPAL3 (class III), were determined. gPAL2 contains an open reading frame encoding a polypeptide of 712 amino acids, interrupted by a 1720 bp intron in the codon for amino acid 130. gPAL3 encodes a polypeptide of 710 amino acids showing 72% similarity with that encoded by gPAL2, and contains a 447 bp intron at the same location. At the nucleotide level, gPAL2 and gPAL3 show 59% sequence similarity in exon I, 74% similarity in exon II, and extensive sequence divergence in the intron, 5' and 3' flanking regions. S1 nuclease protection identified transcription start sites of gPAL2 and gPAL3 respectively 99 bp and 35 bp upstream from the initiation codon ATG, and showed that gPAL2 but not gPAL3 was activated by elicitor, whereas both were activated by wounding of hypocotyls. The 5' flanking region of both genes contain TATA and CAAT boxes, and sequences resembling the SV40 enhancer core. gPAL2 contains a 40 bp palindromic sequence and a 22 bp motif that are also found at similar positions relative to the TATA box in 5' flanking regions of other elicitor-induced bean genes.

Uniform illumination of large targets using a lens array

Inserting an array of nearly 100 similar lenses into a common focal system, the uniformity of the illumination of a target can evidently be improved without being affected by the near-field distribution of laser beams. We report here geometrical- and physical-optics analyses of the lens array and compare them with the experimental results.