谈谈夜盲

麻雀一到夜晚，就看不清东西。有的人像麻雀一样，白天视力挺好的，活动正常自如与常人无二，一到黑暗处或夜晚就看不清东西了，走路深一脚浅一脚，为防止磕绊，常摸索前进，行动困难。所以人们将这种人比喻为“雀盲眼”，医学上称其为夜盲。

Adhesive Patterns of Escherichia coli F4 in Piglets of Three Breeds

Escherichia coli expressing F4 fimbriae is the major pathogenic bacteria that causes diarrhea in piglets before weaning. The adhesion of E. coli to the brush borders of the epithelial cells of piglets is the precondition leading to diarrhea, which in turn is due to the presence of the F4 receptors determined by an autosomal recessive gene on the brush borders of the epithelial cells. In order to clarify the genetic mechanism of the adhesion, an in vitro adhesion experiment was carded out for three variants of E. coli F4 （ab, ac, and ad） in 366 piglets of three pig breeds [Landrace （LR）, Large White （LW）, and Songliao Black （SB）]. The results showed that there existed significant differences （P〈0.001） in the adhesion percentage among the three breeds. Most SB piglets were nonadhesive for all the three variants, whereas most LR piglets were adhesive. Within each breed except for LR, the proportions of the three F4 variants adhering to the brush borders differed significantly. According to the patterns of the adhesion of the three F4 variants in the three breeds, it is very likely that the three F4 variants F4ab, F4ac, and F4ad have different receptors that are controlled by three different loci.

驾驶技术(二)

人的特性——驾驶员的能力与局限性 1.眼睛的功能眼睛对驾驶员来说是最重要的感知器官。眼睛的功能主要表现在视力、视野及辨色力三个方面。 (1)视力人的正常视力为1.0～1.5。若被观察对象或观察者本人在运动中,则运动的速度越高,视力下降越多,下降的程度因人而异,但睡眠不足和身体不适时下降程度会更大。 (2) 视野及辨色力人在注视面前的一个点时,在点的上下左右所能见到的范围称为视野。

眼睛健美与饮食选择

眼睛健美与饮食选择文／陈洪兰图／王晓东眼睛健美不仅能够增添人的神采，也是容貌美丽的标志之一。眼睛的大小、形状，两眼间的距离等，主要受遗传因素的影响，也可以通过美容（化妆）予以某种程度的改变。但眼睛角膜的光洁度，明亮程度，对事物反应的灵敏程度，以及“看...

眼睛与光线

“眼睛与眼镜”是专门为广大消费者和初入眼镜行业的工作人员提供服务与指导的栏目。眼睛,虽人人皆有且视为人类心灵的窗户,但真正了解眼睛的构造、功能、原理以及如何用眼、护眼与配镜矫正的消费者却并不多,就连一些从事配镜的专业人员对此亦是知之甚少。本栏目的开辟,旨在介绍有关眼睛与眼镜关系的一些科普知识,让人们能科学地识眼、用眼、护眼与配镜矫正,以利于眼的健康。欢迎各位方家执牛刀杀鸡,惠赐佳作。来稿直接寄中国眼镜科技杂志编辑部“眼睛与眼镜”栏目收。

Functional morphology of the olfactory organ of the tongue sole, Cynoglossus semilaevis

The morphology and structure of the olfactory organ of Cynoglossus semilaevis Gunther are described. The oval olfactory sacs on both sides differ in size and in the number of lamellae, With those on the abocular side having smaller sacs and fewer lamellae than those on the ocular side. On the ocular side, the average ratio of sac length to eye diameter is 2.1 （i.e.〉1） with an average of 91 lamellae, while on the abocular side, the values were 1.7 （i.e.〉1） and 69, respectively. In addition, the surface morphology varies in different parts of the lamella. The frontal part, near the anterior nostril, is a non-sensory margin with cilia-free epidermal cells. Within this is an internal ciliated sensory area, which is intercalated with ciliated receptor cells and a few ciliated non-sensory cells. Additionally, some dense ciliated non-sensory cells make up a non-sensory area, which also contains cilia-free epidermal cells distributed in patches. In the rear of the olfactory sac near the posterior nostril, the lamellae differ in morphology from those of the frontal olfactory sac but are similar in having few ciliated receptor cells. In other words, the surface of the lamellae in the rear part of the olfactory sac is mainly non-sensory. At present, four types of lamellae （~ E IlIand IV） have been recognized in relation to the pattern of the sensory epithelium. In this study, the frontal and rear lamellae resembled types I and IV, respectively, but are referred to as types r and IV because they are slightly less developed. Data on the ratio of length of lamellae to eye diameter, number of lamellae and the type of surface pattern of the lamellae show that the development of the olfactory system of C. semilaevis facilitates prey capture.

Gastric carcinoid in a patient infected with Helicobacter pylori:A new entity?

There are four types of gastric carcinoid tumors, classified according to their histology and malignant potential. Only a few cases of carcinoid tumors in patients infected with Helicobacter pylori （H. pylor/） have been reported so far. We report a patient infected with H. pylori presenting with a small solitary gastric carcinoid tumor with very low proliferative rate and normal gas- trin levels. The tumor was endoscopically removed and the patient received an eradication therapy against H. pylori. No signs of metastatic disease have been found so far during more than 3 year of follow-up. Infection with H. pylori may cause chronic gastritis with normal or elevated gastrin levels, leading to the develop- ment of gastric carcinoids by mechanisms unrelated to gastrin. Enterochromaffin-like cell tumors related to a chronic H. pylori infection may be considered as a distinct type of gastric carcinoid tumors.

Detection and evaluation of antibodies against neutrophil-activating protein of Helicobacter pylori in patients with gastric cancer

AIM： To detect and evaluate the antibodies against Helicobacter pylori （H pylori） neutrophil-activating protein （HP-NAP） in patients with gastric cancer and other gastroduodenal diseases.METHODS： Recombinant HP-NAP was prepared from a prokaryotic expression system in Escherichia coll. Serum positivity and level of HP-NAP-specific antibodies in sera from 43 patients with gastric cancer, 28 with chronic gastritis, 28 with peptic ulcer, and 89 healthy controls were measured by rHP-NAP-based ELISA. rHP-NAP-stimulated production of interleukin-8 （IL-8） and growth-related oncogene （GROα） cytokines in the culture supernatant of SGC7901 gastric epithelial cells was also detected.RESULTS： The serum positivity and mean absorbancevalue of HP-NAP-specific antibodies in the gastriccancer group （97.7% and 1.01 ± 0.24） were significantly higher than those in the chronic gastritisgroup （85.7% and 0.89 ± 0.14, P 〈 0.005） and healthy control group （27.7% and 0.65 ± 0.18, P 〈 0.001）. The sensitivity and specificity of ELISA for the detection of HP-NAP-specific antibodies were 95.5% and 91.5%, respectively. HP-NAP could slightly upregulate IL-8 production in gastric epithelial cell lines but had no effect on GROα production.CONCLUSION： Infection with virulent H py/ori strains secreting HP-NAP is associated with severe gastroduodenal diseases, and HP-NAP may play a role in the development of gastric carcinoma, rHP-NAP- based ELISA can be used as a new method to detect H pylori infection. The direct effect of HP-NAP on gastric epithelial cells may be limited, but HP-NAP may contribute to inflammatory response or carcinogenesis by activating neutrophils.

Tumor Susceptibility in Proteus Syndrome: a Case Report

PROTEUS syndrome is characterized by patchy and progressive overgrowth affecting multiple tissues, including bone, soft tissue, and skin, along with susceptibility to the development oftumors. It was originally described by Cohen and Hayden in 19791 and named by Wiedmann in 1983.2 The cause of Proteus syndrome is proposed to be a somatic mutation that is lethal in non-mosaic state; cells derived from the mutated cell line carrying this mutation result in anomalies in multiple tissues.3 The clinical manifestations are variable,

Expression of Cytochrome P450nor in Escherichia coli , Purification and Preparation of Polyclonal Antibodies

Cytochrome P450nor gene was cloned into the expression vector pET-28 to yield the recombinant expression plasmid pET-P450nor, which could direct the synthesis of a eukaryotic derived protein in Escherichia coli BL21. The vector allows overproduction and single-step purification of (His) 6-tagged cytochrome P450nor by the facilitation of metal (Ni 2+ ) chelate affinity chromatography. The expression level of cytochrome P450nor was high at 30℃ after IPTG induction. SDS-PAGE and Western blot analysis showed a specific band (about 43 kDa). The overproduced cytochrome P450nor was purified to electrophoretic homogeneity within 2.5 h and about 20.8 mg purified protein was obtained from 2 L cell culture. The proliferation of SSMC-7721 cell line could be inhibited by cytochrome P450nor. Rabbit polyclonal antibodies (titer over 64 000 ) were produced against recombinant cytochrome P450nor and proved to be very useful for immunoblotting study. Availability of this expression system and specific antibodies should facilitate characterization of the role of cytochrome P450nor in the metabolism of NO.

Expression of Overlapping PCR-generated Shiga Toxin B Gene Fragment in E. Coli and Its Ascitic Polyclonal Antibody

The mature Shiga toxin B （StxB） gene was optimized and generated by overlapping PCR. Recombinant expression vector pQE40-DHFR/StxB was constructed when the gene was cloned into pQE fusion expression vector. Induced by Isopropyl β-D-thiogalactoside （IPTG）, the DHFR/StxB fusion protein was highly expressed to the level of 41.36% in E. coli MI5 cells. The 35 kDa fusion protein with a 6 His-tag was one-step purified from inclusion bodies using Ni-NTA affinity chromatography column under denaturing conditions, and was refolded by dialyzing with a decreasing urea gradient. Purified DHFR/StxB fusion protein was used to immunize Kunming mice for generating the ascitic polyclonal antibody against recombinant StxB protein by injecting sarcoma 180 cells and the titer ofascitic polyclonal antibody is up to 1： 1× 10^6 detected by the indirect enzyme linked immunosorbent assy （ELISA）. Western immunoblotting analysis revealed that the ascitic polyclonal antibody against StxB had a specific affinity for a 70 kDa shiga toxin protein of Shigella dysenteriae type 1. It is a new simple and quick method to produce a large amount of ascitic polyclonal antibody. The antibody is used to develop immunological method for detecting shiga toxin.

Expression,purification and identification of LBD domain of human PPARδ in E.coli

Peroxisome proliferator-activated receptors （PPARs） are ligand-activated transcription factors known to play a pivotal role in regulations of metabolism. In order to yield soluble ligand binding domain of PPARδ （PPARδLBD） for screening ligands, the cDNA was amplified using total RNA from HepG2 cells by RT-PCR. Then the enzyme-digested product was inserted . downstream of the malE gene in the vectorpMAL-p2x, which encoded maltose-binding protein （MBP）, resulting in the expression of an MBP-PPARδLBD fusion protein. The recombinant plasmid was transformed into E. coli TBI that was cultured shakily at 30 ℃, 200 r/min and induced by 0.4 mmol/L IPTG for 6 h. The cells were harvested by centrifugation and broken by sonication. The expressed fusion protein was soluble and accounted for 0.31 of the total protein in the supernatant. Western blot analysis showed that the expressed MBP-PPARδLBD could bind to anti-MBP-antibody. The MBP-PPARδLBD fusion protein of 77 kDa and the PPARδLBD protein of 34 kDa were obtained by amylose-resin affinity chromatography without or with digestion of Factor Xa. They were both homogeneity, judged by SDS-PAGE. The recombinant MBP-PPARδLBD and PPARδLBD protein with high purity is obtained, which provides the necessary material for screening and researching PPARδ ligands.

Expression of Rice Gall Dwarf Virus Outer Coat Protein Gene (S8) in Insect Cells

To obtain the P8 protein of Rice gall dwarf virus (RGDV) with biological activity,its outer coat protein gene S8 was expressed in Spodoptera frugiperda (Sf9) insect cells using the baculovirus expression system.The S8 gene was subcloned into the pFastBacTM1 vector,to produce the recombinant baculovirus transfer vector pFB-S8.After transformation,pFB-S8 was introduced into the competent cells (E.coli DH10Bac) containing a shuttle vector,Bacmid,generating the recombinant bacmid rbpFB-S8.After being infected by recombinant baculovirus rvpFB-S8 at different multiplicities of infection,Sf9 cells were collected at different times and analyzed by SDS-PAGE,Western blotting and immunofluorescence microscopy.The expression level of the P8 protein was highest between 48-72 h after transfection of Sf9 cells.Immunofluorescence microscopy showed that P8 protein of RGDV formed punctate structures in the cytoplasm of Sf9 cells.

从声、光的特性看声光弹药

声光弹在某些特定的反恐怖环境中发挥着独有的作用,取得了骄人的战绩。如1984年,伊朗驻英国大使馆被恐怖分子占领,被扣压的人质随时都有生命危险,英国反恐怖部队奉命解救人质,突击队员在进入被恐怖分子占领的房间前,向房内投掷了两枚声光弹,巨大的声响和强烈的闪光使恐怖分子惊恐万分,不知所措,突击队员抓住这一有利时机突入,击毙了恐怖分子,成功地解救出了人质。声光弹何以有如此神威?其实它是利用了人体生理特征的弱点,使人产生某些生理反应,从而丧失了正常的活动和判断能力。

电影活动的原理

我们在看电影时,可以从银幕上看到连续活动的图像。但是,当我们观看电影影片时,却只能看到一幅幅静止的画面。这一幅幅静止的画面通过电影机放映到银幕上怎么会活动起来的呢? 电影影片上一幅幅独立的、静止的画幅经电影放映机放映到银幕上能形成清晰的活动影像,其原因有视觉暂留、心理作用及电影机械间歇运动的配合等3个方面。

几种原因奇特的夜盲

"上帝"赐与我们每一个人一双眼睛,于是,我们能够在白天看到蓝色的海洋;绿色的树,红色的火焰,白色的雪,五颜六色的花朵。即使在月色朦胧的晚上,我们也能辨别出马路、电线杆、池塘、垂柳……可是有些人在白天才能看到缤纷的世界,一到晚上就什么也看不到,似乎世界成了一片黑色。这种情况在医学上就叫做夜盲。很多人知道,机体缺乏维生素A会产生夜盲。

Protein photocrosslinking reveals dimer of dimers formation on MarR protein in Escherichia coli

The multiple antibiotic resistance regulatory protein(MarR) binds to two promoter sites on the marO operator in Escherichia coli.Our study showed that more than one MarR dimer proteins bound to either of its two promoter sites(Site I and Site II),suggesting that MarR might form higher complexes than homodimers when bound to DNA inside E.coli cells.To further verify this hypothesis,we site-specifically incorporated a photocrosslinking probe at the interface between two MarR dimer proteins.Photolysis in living E.coli cells revealed a covalent linkage between the two interdimer subunits of MarR,suggesting that MarR forms dimer of dimers in vivo.

Characterization of the viral fibroblast growth factor homolog of Helicoverpa armigera single nucleopolyhedrovirus

Fibroblast growth factor(FGF) is found throughout multicellular organisms; however, fgf homologs(vfgf) have only been identified among viruses in lepidopteran baculoviruses. The function of v FGFs from Group I alphabaculoviruses, including Autographa californica multiple nucleopolyhedrovirus(Ac MNPV) and Bombyx mori nucleopolyhedrovirus(Bm NPV), involves accelerated killing of infected larvae by both viruses. The v FGF of Group II alphabaculovirus is structurally different from that of Group I alphabaculovirus, with a larger C-terminal region and additional N-linked glycosylation sites. In this study, we characterized the Group II alphabaculovirus v FGF of Helicoverpa armigera single nucleopolyhedrovirus(Hear NPV). The transcription and expression of vfgf was detected at 3 h and 16 h post-infection in Hear NPV-infected cells. To further study v FGF function, we constructed vfgf-knockout and-repaired Hear NPV bacmids and investigated their affect in both cultured cells and insects. Deletion of vfgf had no effect on budded-virus production or viral DNA replication in cultured Hz AM1 cells. However, bioassays showed that Hear NPV vfgf deletion significantly increased the median lethal dose and delayed the median lethal time by ~12 h in the host insect when the virus was delivered orally. These results suggested that v FGF is an important virulent factor for HearN PV infection and propagation in vivo.