人类活动影响下新疆生态环境的一些变化

人类活动引起的新疆生态环境变化主要有以下几方面:1.河流流程缩短,河水矿化度和泥沙含量增加;2.湖泊水位下降,湖面缩小或变干,湖水矿化度升高;3.森林破坏,面积缩小;4.草场的产草量降低,牧草质量下降; 5.土壤次生盐渍化、沼泽化和肥力下降;6.土地沙漠化不断扩大。     

Synthesis, resolution and charge-donor properties of six tryptophan analogues.

In order to investigate the special function of tryptophan in peptide hormones, six tryptophan analogues have been synthesized, in which structural resemblance has been grossly retained and potentially essential properties have only partially been varied. The L-enantiomers have been isolated after enzymatic digestion of racemic dipeptide derivatives, and charge-transfer properties of the compounds have been studied.     

A kinetic model of peroxidation in a lipid bilayer

The structure, thermodynamic, and kinetic features of polyunsaturated fatty acids derivatives as the main substratum of lipid peroxidation (POL) have been considered. The heats of key POL reactions have been estimated. Kinetic consequences of these estimations have been analyzed. The dependence of POL rate on O2 concentration have been considered in detail both in the absence and in the presence of antioxidants. The essential features of POL processes in lipid bilayers resulting from the specific structure and molecular dynamics have been discussed.     

Host defense mechanisms of cephalopods

Humoral and cellular mechanisms of defense have been described for cephalopods, a relatively advanced group of mollusks. Typical of other mollusks, cephalopod agglutinins are the most documented component of humoral immunity. Lectins, which have agglutinating properties, have been described and characterized from octopuses. Agglutinins from cephalopod hemolymph have also been shown to agglutinate a variety of vertebrate red blood cells, as well as potential bacterial pathogens. Hemocytes are the primary component of cellular immunity. Although the hemocyte role in phagocytosis has been extensively studied in other mollusks, the mechanisms of phagocytosis have not been described extensively for cephalopods. Cephalopod hemocytes have phagocytic capabilities and may function in encapsulation and neutralization of foreign substances; however, the effects of environmental factors and the full extent of phagocytic capabilities of cephalopod hemocytes have not been reported. Hemocytes from cephalopods have a role in wound healing and inflammation which have been reported in detail by several investigators.     

Diagnosis of Helicobacter pylori

The different invasive and noninvasive diagnostic tests for Helicobacter pylori have been applied mainly in emerging countries. Molecular methods have been developed, especially a test for detection of H. pylori and its clarithromycin resistance directly from stools. The long-term effects of eradication on histologic lesions have been studied in a meta-analysis and the prognostic value of post-treatment in gastric mucosa-associated lymphoid tissue lymphoma has been assessed. An operating link for gastritis assessment (the OLGA staging) has also been published. Attempts to simplify the urea breath test protocol have been made, and new stool antigen tests have been proposed and compared to those previously available.     

Results of cytogenetic examinations in 255 married couples with a history of infertility]

The results of cytogenetic examination carried out in 255 couples with a history of infertility have been analysed. Chromosomal aberrations have been detected in 15 examinations (6.7%) with predominance of translocations (mutual - 3.6%; Robertson' - 1.3%). Identified aberrations have been noted in 9 women and 6 men. The obtained results have been analysed in relation to the number of abortions, dead and live newborn babies with inherited abnormalities. It was found that the incidence of chromosomal aberrations increases with the number of the spontaneous abortions in anamnesis. Such aberrations have also been more frequent in the families in which spontaneous abortions have been accompanied by other fertility disorders.     

Measurement and study of the nose and face and their correlations in the young adult of Han nationality

The measurement of 13 items in the face and nose of 220 young adults (110 males and 110 females) of the Han nationality between the ages of 18 and 21 years has been done in the Henan Province of China. The means and standard deviations have been obtained, and the significant differences in many items between males and females have been proved. Some items influencing outer nasal shape have been analyzed. The correlations between nose height, nose length, and morphologic facial height and physiognomic facial height have been discussed. The ratio and amount of nasal breadth to facial breadth and nasal breadth to interocular breadth have been compared and analyzed, and the differences among the different races and between the sexes have been explained.     

Colorectal carcinoma antigens detected by hybridoma antibodies.

Hybridoma cells which secrete colorectal carcinoma-specific antibodies have been produced and used to study the antigenic structure of these tumor cells. Nineteen antibodies have been studied in detail, and 15 of these are colorectal carcinoma specific. Only two antibodies reactive with carcinoembryonic antigen (CEA) have been discovered and five other antibodies that react with distinct epitopes on the cell surface have been defined. Several antigens with distinct molecular characteristics have been shown to exist by use of hybridoma antibodies. Six hybridoma antibodies have been shown to mediate antibody-dependent cell-mediated cytotoxicity (ADCC).     

Analysis of the aliphatic 1H-NMR spectrum of plasminogen kringle 4. A comparative study of human, porcine, bovine and chicken homologs

The aliphatic 1H-NMR spectrum of the kringle 4 domain of human plasminogen has been studied via two-dimensional chemical shift correlated (COSY) and nuclear Overhauser correlated (NOESY) experiments at 300 MHz and 620 MHz. A number of aliphatic proton spin systems have been identified and several definite assignments have been made. This was mainly achieved by comparison of the human kringle 4 spectrum with spectra of the porcine, bovine and chicken homologs and also with that of the kringle 1 from human plasminogen on which we have reported previously. The three valyl and two leucyl residues of human kringle 4 have been assigned. The eleven threonyl spin systems have been identified via a RELAYED-COSY experiment and Thr17 has been assigned. The three alanyl spin systems have been identified and assigned. Six seryl spin systems have been identified and the signals from the seven glycyl residues of human kringle 4 have been located with Gly45 assigned. Furthermore, 24 AMX spin systems have been mapped in the COSY spectrum of human kringle 4 and H alpha-H beta,beta' spin systems of Tyr2, Tyr41, Tyr50, Tyr74, Trp25 and Trp62 have been assigned. From the spectrum of a deglycosylated chicken homolog, the epsilon-methyl singlets of Met28 and Met48 have been assigned. Finally, ligand effects on selected aliphatic resonances were observed which could be analyzed in terms of residues likely to neighbor the kringle lysine-binding site.     

Sedimentation equilibrium of proteins in density gradients.

The technique of sedimentation equilibrium in density gradients in the analytical ultracentrifuge has been applied to the study of proteins. A variety of effects and procedures including the use of density marker beads, the effects of pressure on buoyant density and pH, and the calculation of compositional density gradient proportionality constants and density--refractive index relations have been developed. The buoyant densities of twenty-four proteins have been measured and hydration values computed. The buoyant titrations of six proteins have been measured. These data have been interpreted in terms of the buoyant titrations which have been obtained for six ionizable homopolypeptides, five copolypeptides, two non-ionizable homopolypeptides and three chemically modified proteins. Spectropolarimetry and potentiometric titrations were employed to further interpret these data. Approximate values for dissociation constants, numbers of ionizable residues, and the nature of ions bound or dissociated upon ionization have been obtained. The relation between potentiometric and buoyant titrations and the use of density gradient centrifugation as a probe for protein structure have been explored.     

Imaging erythrocytes under physiological conditions by atomic force microscopy

Since its invention in the mid 1980s atomic force microscopy has revolutionised the way in which surfaces can be imaged. Close to atomic resolution has been achieved for some materials and numerous images of molecules on surfaces have been recorded. Atomic force microscopy has also been of benefit to biology where protein molecules on surfaces have been studied and even whole cells have been investigated. Here we report a study of red blood cells which have been imaged in a physiological medium. At high resolution, the underlying cytoskeleton of the blood cell has been resolved and flaws in the cytoskeleton structure may be observed. Comparison of the normal 'doughnut' shaped cells with swollen cells has been undertaken. Differences in both the global properties of the cells and in the local features in cytoskeleton structure have been observed.     

Upper lobe lobectomy and concomitant thoracoplasty in pulmonary tuberculosis. A preliminary report

In this, a preliminary report, the advantages and disadvantages of upper lobe lobectomy and concomitant thoracoplasty in tuberculosis have been summarized. There has been no undue increase in the operative hazard, there have been no complications, and the immediate results have been entirely satisfactory.Twenty-six patients were subjected to a combined operation (17 upper lobectomy-thoracoplasty and nine pneumonectomy-thoracoplasty) with one postoperative death. Indications for primary lobectomy have been discussed. The technique of resection and concomitant thoracoplasty has been briefly described.     

Synthesis and partial characterization of hydrogels obtained via glutaraldehyde crosslinking of acetylated chitosan and of hyaluronan derivatives

Hydrophilic networks based on functionalized hyaluronic acid and on partially acetylated chitosan, respectively, have been obtained. In the case of hyaluronic acid (HA), primary amino functionalities have been introduced along the polysaccharide chains. The ensuing derivatives, i.e., HA-lysine (HA-K), HA-diamino pentane (HA-DAP), and HA-glycine-lysine (HA-GK), have been characterized by high field NMR spectroscopy. NMR 2D-DOSY experiments have allowed us to optimize the purification procedure. Chitosan was made soluble in water by partial acetylation. Cross-linking reactions have been performed using glutaraldehyde. The obtained networks have been qualitatively characterized by means of (13)C CP-MAS NMR technique. The hydrogels have been characterized also in terms of water uptake.     

Degradation of chlorinated nitroaromatic compounds

Chlorinated nitroaromatic compounds (CNAs) are persistent environmental pollutants that have been introduced into the environment due to the anthropogenic activities. Bacteria that utilize CNAs as the sole sources of carbon and energy have been isolated from different contaminated and non-contaminated sites. Microbial metabolism of CNAs has been studied, and several metabolic pathways for degradation of CNAs have been proposed. Detoxification and biotransformation of CNAs have also been studied in various fungi, actinomycetes and bacteria. Several physicochemical methods have been used for treatment of wastewater containing CNAs; however, these methods are not suitable for in situ bioremediation. This review describes the current scenario of the degradation of CNAs.     

Identification of small RNAs in diverse bacterial species

Small, non-coding bacterial RNAs (sRNAs) have been shown to regulate a plethora of biological processes. Up until recently, most sRNAs had been identified and characterized in E. coli. However, in the past few years, dozens of sRNAs have been discovered in a wide variety of bacterial species. Whereas numerous sRNAs have been isolated or detected through experimental approaches, most have been identified in predictive bioinformatic searches. Recently developed computational tools have greatly facilitated the efficient prediction of sRNAs in diverse species. Although the number of known sRNAs has dramatically increased in recent years, many challenges in the identification and characterization of sRNAs lie ahead.     

Upper Lobe Lobectomy and Concomitant Thoracoplasty in Pulmonary Tuberculosis—A Preliminary Report

In this, a preliminary report, the advantages and disadvantages of upper lobe lobectomy and concomitant thoracoplasty in tuberculosis have been summarized. There has been no undue increase in the operative hazard, there have been no complications, and the immediate results have been entirely satisfactory.Twenty-six patients were subjected to a combined operation (17 upper lobectomy-thoracoplasty and nine pneumonectomy-thoracoplasty) with one postoperative death.Indications for primary lobectomy have been discussed.The technique of resection and concomitant thoracoplasty has been briefly described.     

Uridine insertion/deletion RNA editing in trypanosome mitochondria: a complex business

The basic mechanism of uridine insertion/deletion RNA editing in mitochondria of kinetoplastid protists has been established for some time but the molecular details remained largely unknown. Recently, there has been significant progress in defining the molecular components of the editing reaction. A number of factors have been isolated from trypanosome mitochondria, some of which have been definitely implicated in the uridine insertion/deletion RNA editing reaction and others of which have been circumstantially implicated. Several protein complexes have been isolated which exhibit some editing activities, and the macromolecular organization of these complexes is being analyzed. In addition, there have been several important technical advances in the in vitro analysis of editing. In this review we critically examine the various factors and complexes proposed to be involved in RNA editing.     

Development of a gas chromatography mass spectrometry assay for the two eosinophil chemotactic factors of anaphylaxis

Gas chromatography mass spectrometry has been used for over a decade for the determination of the amino acid sequences of fragment peptides derived from larger parent molecules. The majority of these fragments have from four to seven residues and several different methods of derivatization have been devised. Few reports have been published in which similar techniques have been used for the quantification of such peptides, but there is a growing list of small peptides which have been shown to have biological activity in their own right. This report is concerned with the development of a gas chromatographic mass spectrometric assay for the two eosinophil chemotactic peptides, Val-Gly-Ser-Glu and Ala-Gly-Ser-Glu, which appear to have a role to play in the course of the inflammatory process in skin disorders.     

Starch phosphorylase enzymes in developing and germinating pea seeds

Phosphorylase has been fractionated during development and germination of seeds of smooth and wrinkled-seeded peas. The total phosphorylase levels have been compared. In addition, a number of other pea tissues and other legumes have been examined. Some kinetic properties of the two enzymes present have been measured. Both enzymes have been further purified by affinity chromatography on Sepharose 4B-starch columns and by sequential gel filtration in the absence and presence of amylopectin. The MW and sub-unit structures of the two enzymes have been examined and their possible roles discussed.