Structural parts involved in activation and inactivation of the sodium channel

Structure-function relationships of the sodium channel expressed in Xenopus oocytes have been investigated by the combined use of site-directed mutagenesis and patch-clamp recording. This study provides evidence that the positive charges in segment S4 are involved in the voltage-sensing mechanism for activation of the channel and that the region between repeats III and IV is important for its inactivation.     

Two tobacco DNA-binding proteins with homology to the nuclear factor CREB

The 35S promoter of the cauliflower mosaic virus (CaMV) contains a tandem repeat of the sequence TGACG in the region -83 to -63. This 21-base pair (bp) sequence, called as-1, is involved in root expression of the 35S promoter. When inserted in a promoter of a gene expressed specifically in photosynthetic tissues, as-1 confers high level expression in roots. We have described a factor, ASF-1, that binds specifically to as-1 in vitro. There is a good correlation between ASF-1 binding affinity to as-1 related sequences in vitro and the function of these sequences in vivo. These results strongly suggest that ASF-1 is responsible for the function of as-1. Here we report the isolation of tobacco complementary DNA clones encoding two TGACG-sequence-specific binding-proteins (TGA1a and TGA1b). Sequence analysis of the cDNA clones shows that both proteins contain a basic region that shows high homology to a stretch of basic amino acids in the nuclear factors CREB, GCN4, and c-Jun to a 'leucine-zipper' region. On the basis of binding specificity we propose TGA1a to be a good candidate for ASF-1.     

快速检验食品中沙门氏菌和O157:H7大肠杆菌

利用沙门氏菌快速检验装置(Oxoid公司出口）和可视免疫沉淀物（VIP）试剂盒（BioControlSystems公司出口）对广西桂林市的七星区某农贸市场的20种食品进行了沙门氏菌和O157：H7大肠杆菌的快速抽样检验，结果发现，其中的11种食品的沙门氏菌呈阳性反应，4种食品的O157：H7大肠杆菌也呈阳性反应，与目前国内普遍使用的传统检验方法相比，该方法具有快速、简便、高效、准确的特点。     

Two-tone distortion in the basilar membrane of the cochlea

When humans listen to pairs of thnes they hear additional tones, or distortion products, that are not present in the stimulus. Two-tone distortion products are also known as combination tones, because their pitches match combinations of the primary frequencies (f1 and f2, f2 greater than f1), such as f2-f1, (n + 1)f1-nf2 and (n + 1)f2-nf1 (n = 1, 2, 3...). Physiological correlates of the perceived distortion products exist in responses of auditory-nerve fibres and inner hair cells and in otoacoustic emissions (sounds generated by the cochlea, recordable at the ear canal). Because the middle ear responds linearly to sound and neural responses to distortion products can be abolished by damage to hair cells at cochlear sites preferentially tuned to the frequencies of the primary tones, it was hypothesized that distortion products are generated at these sites and propagate mechanically along the basilar membrane to the location tuned to the distortion-product frequency. But until now, efforts to confirm this hypothesis have failed. Here we report the use of a new laser-velocimetry technique to demonstrate two-tone distortion in basilar-membrane motion at low and moderate stimulus intensities.     

A bayesian forecasting model for sequential bidding

In this paper we consider the problem facing a company in selecting the values of bids to submit on a sequence of contracts put out to tender. A simple-to-implement Bayesian forecasting model is presented, based on a steady Dirichlet process whose states are indexed by the possible bid decisions open to the company. The model gives an explicit algorithm for calculating the state probabilities, needing only data on the lowest bid made by the company's competitors. The flexibility of the basic model makes it a potentially powerful forecasting system for use by companies bidding for contracts.     

Binding of iron by rat placental tissues

Zusammenfassung Nachweis, dass das Eisenbindungsvermögen der Dottersackplacenta bedeutend grösser ist als bei der chorioallantoiden Placenta und dass diese auch unter der Einwirkung von den Stoffwechsel beeinflussenden Stoffen ein verschiedenes Verhalten zeigt.

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This work was supported by U.S. Public Health Service Grant No. HD05016 and Predoctoral Fellowship Grant No. FO1-DE41063 to R.J.B.G.     

Antihypertensive and central nervous system depressant properties of 3-(γ-p-fluorobenzoyl propyl) 2,3,4,4a,5,6-hexahydro-1(H)-pyrazino(1,2-a) quinoline hydrochloride (compound 69-183, centpyraquin)

Zusammenfassung Centpyraquin (3-(-p-fluorobenzyl propyl) 2,3,4,4a,5,6-hexahydro-1(H)-pyrazino (1,2-a) quinoline hydrochloride) zeigte hypotensive Aktivität bei narkotisierten wie auch bei wachen Katzen. Es senkt auch den Blutdruck bei Ratten mit nephrogenem Hochdurck. Die Hypotension scheint auf einem peripheren Mechanismus zu beruhen.

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Thanks are due to Drs.M. L. Dhar andN. Anand for their interest in the work.

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Communication No. 1600 from the Central Drug Research Institute; Lucknow.     

HLA-DQ is epistatic to HLA-DR in controlling the immune response to schistosomal antigen in humans

Antigens that produce an antibody response in some members of a species may fail to do so in others. The response to an antigen is controlled by a gene termed the immune response (Ir) gene, which is transmitted as a single dominant trait. We have provided evidence for similar immune suppression (Is) genes which control non-responsiveness through the antigen specific suppressor T cell. The non-responsiveness is also dominantly inherited and the Is genes are linked to the histocompatibility (HLA) antigen system. Here we report that the HLA-DR2 molecule from a non-responder haplotype (HLA-Dw12-DR2-DQwl) is required for the proliferative T cell response to schistosoma japonicum (Sj) antigen, as a restriction element, indicating that the HLA-DR2 is the product of the Ir gene, and that the HLA-DQwl molecule of the non-responder haplotype is important in the antigen-specific suppression of the response to this antigen, suggesting that it is the product of the Is gene. We therefore conclude that the HLA-DR and DQ molecules, which are controlled by the distinct genes in the MHC multigene family, regulate immune response and immune suppression and that the gene for HLA-DQ is epistatic to that for HLA-DR in controlling the immune response to schistosomal antigen in humans.