Recovery of Cell-Bound Interferon

Interferon could be recovered from homologous cells to which it was applied but could not be recovered from heterologous cells. The amount of interferon that could be recovered from cells corresponded to the sensitivity of the cells to the antiviral activity of the interferon: mouse embryo fibroblasts, which were 5 to 10 times as sensitive as L-929 cells to interferon, bound 5 to 10 times more interferon than the latter, whereas Lpa cells, which were only one-third as sensitive as L-929 cells to interferon, bound only one-third as much as the latter. The concentration of cell-bound interferon was as much as 150 times the extracellular concentration of interferon applied to the cells. Interferon bound to cells at 4 C with the same efficiency as it did to cells at 37 C, and actinomycin D-treated cells bound interferon as well as normal cells. Even though the total amount of interferon bound to cells was as much as 30% of the amount of interferon applied to them, no loss of antiviral activity was detectable from the medium.     

Limitations of pH-potentiometric titration for the determination of the degree of deacetylation of chitosan

The degree of deacetylation (DDA) of chitosan determines the biopolymer's physico-chemical properties and technological applications. pH-Potentiometric titration seems to offer a simple and convenient means of determining DDA. However, to obtain accurate pH-potentiometric DDA values, several factors have to be taken into consideration. We found that the moisture content of the air-dry chitosan samples can be as high as 15%, and a reasonable fraction of this humidity cannot be removed by ordinary drying. Corrections have to be made for the ash content, as in some samples it can be as high as 1% by weight. The method of equivalence point determination was also found to cause systematic variations in the results and in some samples extra acid as high as 1 mol% of the free amino content was also identified. To compensate for the latter effect, the second equivalence point of the titration has to be determined separately and the analytical concentration of the acid be corrected for it. All the corrections listed here are necessary to obtain DDA values that are in reasonable agreement with those obtained from (1)H NMR and IR spectroscopic measurements. The need for these corrections severely limits the usefulness of pH-metry for determining accurate DDA values and thus potentiometry is hardly able to compete with other standard spectroscopic procedures, that is, (1)H NMR spectroscopy.     

Phytoremediation of Organic Contaminants: A Review of Phytoremediation Research at the University of Washington

As overwhelmingly positive results have become available regarding the ability of plants to degrade compounds such as trichloroethylene, phytoremediation studies are expanding. Studies to determine the potential for phytoremediation of fully chlorinated compounds, such as carbon tetrachloride and tetrachloroethylene, brominated compounds, such as ethylene dibromide and dibromochloropropane, and nonhalogenated compounds, such as methyl-t-butyl ether (MTBE), are underway. When using phytoremediation, it is important to select not only a plant that is capable of degrading the pollutant in question, but also one that will grow well in that specific environment. In ecologically sensitive areas, such as the Hawaiian Islands, only plants native to the area can be used. One way to supplement the arsenal of plants available for remedial actions is to utilize genetic engineering tools to insert into plants those genes that will enable the plant to metabolize a particular pollutant. Hybrid technologies, such as using plants in pumping and irrigation systems, also enable plants to be used as a remedial method when the source of the pollutant is beyond the reach of plant roots, or when planting space directly over the pollutant is unavailable or restricted. Thus, the potential uses of phytoremediation are expanding as the technology continues to offer new, low-cost remediation options.     

City of Details: Interpreting the Personality of London

This article investigates the ways in which a group of enthusiasts for London constitute their city. The 'personality' attributed to London is described, as well as the interpretive acts that reveal it. These people, who also lead walking tours across the city, privilege 'detail' as their term of analysis. The article examines the identified qualities of that category, in particular its perceived capacity to animate the plural time-spaces of the city. This sensitivity to detail is presented as part of a sensing of place, which allows people to regard themselves as uniquely able to see the city. The article is intended as a contribution to the ethnography of London.     

阿米巴巨大病毒及其潜在致病性研究进展

近年来,通过阿米巴共培养等方法发现了一批新的病毒,统称为巨大病毒（giant virus）。它们分布广泛,不仅有很大的病毒颗粒,基因组也非常庞大,还编码许多与蛋白质合成相关的基因,突破了人们对病毒的一般认识,引发了对病毒起源和本质的讨论。巨大病毒被认为有潜在致病性。本文综述了在人体中针对两类最早发现的巨大病毒--拟菌病毒（Mimivirus）和马赛病毒（Marseillevirus）开展的血清学、分子生物学、宏基因组检测、病毒分离及其对哺乳动物感染和致病性研究的进展     

Reproductive performance of Bhotia women of Mana Valley

This paper reports the preliminary findings on the reproductive performance of 52 Bhotia women from the Mana Valley (Uttar Pradesh; elevation 10 560 ft.), who had approached menopause. The total amount of time available for reproduction and the total time used for effective reproduction as well as the period, which has been wasted as a result of sociocultural and biological factors, have been calculated. The total time available to Bhotia women for reproduction is found to be 1584 years, out of which 1563 years (98.67%) were used for effective reproduction. The reproductive wastage as a result of socio-economic and biological circumstances is calculated as 21 years only or 0.40 years per woman. All pregnancies as well as lactation operate to reduce fecundability. The various family limiting methods also lower the reproductive performance. A comparison has been made with the results of similar studies in other populations.     

Role of alimentary hyperglycemia in the pathogenesis of several disorders of lipid metabolism]

Alimentary hyperglycemia in rabbits was found to be accompanied by increase in cholesterol level, as well as in the amount of triglycerides in the blood sera. Progressive increase in the serum concentration of pre-beta lipoproteids (serving as endogenous tryglyceride carrier) has also been demonstrated. A short-term feeding with cholesterol against the background of hyperglycemia in rabbits appeared to result in early marked atherosclerotic changes, as compared to those in control group of normoglycemic animals.     

Effect of conditions of cultivation on quantitative assessment of the viability of an organism's tissues]

Viability of mouse kidney tissue explants as estimated quantitatively according to their growth in plasmafree culture depends on some factors connected with cultivation conditions. Methods of serum preparation, pH of the medium, as well as peculiarities of tissue explants distribution in cultivation, their size and fastness of attachment to the substrate proved to influence the quantitative estimation of the tissue explants viability.     

Structure of mycoside F, a family of trehalose-containing glycolipids of Mycobacterium fortuitum

Nuclear magnetic resonance spectroscopy, fast-atom bombardment mass spectrometry, gas chromatography-mass spectrometry, as well as chemical degradations were used to elucidate the structure of the major glycolipids of Mycobacterium fortuitum. Three main glycoconjugates were detected and their structures established as 2,3-diacyl, 2,3,4- and 2,3,6-triacyl trehalose. The characteristic infrared spectrum which led to their original designation as mycoside F, a family of glycolipids limited in distribution to M. fortuitum, was due to the nature of the fatty acyl substiuents identified primarily as 2-methyl-octadecen-2-oyl. The antigenic glycolipids typified the biovar. fortuitum, thus allowing its easy recognition from the C-mycoside glycopeptidolipid-containing biovar. peregrinum.     

Biochemical mechanism of combined effect of ethambutol and sparfloxacin against Mycobacterium smegmatis

M. smegmatis cells grown in the presence of combination of ethambutol (EMB) and sparfloxacin (SPX) had decreased level of total cellular lipids as compared to control as well as cells grown in the presence of sub-inhibitory concentration (MIC50) of individual drugs. Amongst various phospholipids analyzed, maximum decrease was observed in the content of phosphatidylinositolmannosides (PIMs) of the cells grown in combination of EMB and SPX. In contrast, the subcellular distribution of phospholipids revealed a significant increase in PIMs content of both cell wall and cell membrane of the cells grown in the presence of combination of drugs as compared to control as well as individual drugs. Mycolic acids of M. smegmatis cells were found to be main targets as combination of drugs resulted in significant decrease in total cellular as well as cell wall mycolic acids as compared to control and individual drugs. Changed lipid composition of M. smegmatis cells grown in the presence of MIC50 of EMB, SPX and combination resulted in significant surface changes as was evident from decreased limiting fluorescence (Fmax) intensity of 1-anilinonaphthalene-8-sulfonate (ANS). Thus, the results of this study suggested that ethambutol and sparfloxacin in combination exerted their antimycobacterial effect principally due to their action on phosphatidylinositolmannosides (PIMs) and mycolic acids, which form the permeability barrier of mycobacteria.     

Studies of the site and mode of biosynthesis of tobacco trichome exudate components

Detached glandular trichome head preparations and epidermal strips with and without trichome heads were used to identify glandular trichome heads as the site of sucrose ester biosynthesis in tobacco. Carbon dioxide in solution as well as sucrose, glucose, and acetate were shown to serve as precursors to both sucrose esters and duvatrienediol diterpenes in detached trichome heads or epidermal strips, and gaseous CO2 was also efficiently utilized by epidermal strips. Thus, glandular heads can biosynthesize these principal exudate components from a molecule as simple as CO2. While formation of duvatriendiols from all precursors tested and conversion of sucrose and glucose to sucrose esters was light dependent, utilization of acetate to label the 6-O-acetyl group of the glucose moiety of sucrose esters occurred equally well in light and dark. The data suggest that CO2 and/or monosaccharides produced in trichome head cells and perhaps that supplied by other epidermal cells can act as carbon sources for sucrose ester and duvatrienediol biosynthesis which occurs in the glandular trichome head.     

Effect of the stereoisomers of glutamic acid on the vital activity of auxotrophic mutant producers of lysine]

Studies of L, D and DL-forms of glutamic acid as the sole nitrogen source or as a supplement to the major nitrogen source--ammonium sulphate have demonstrated that in the first case all forms of glutamic acid are assimilated by auxotrophic mutants--lysine producers. However, the lysine synthesis was very low, when L-glutamic acid was used as the only nitrogen source. Glutamic acid at a concentration of 0.01 M applied as a supplement to the major source of nitrogen acted as a stimulator of lysine synthesis, slightly inhibiting biomass increment. That was true of every form of glutamic acid, especially of DL-glutamic acid.     

唐古特白刺单果优株果序性状变异研究

依据单果大小和口感等指标选择出39个唐古特白刺(Nitraria tangutorum Bobr．)果用优株。并以此为试验材料进一步就果序性状变异进行了研究,结果表明：白刺中选优株的果大小、果重、核果比等单果性状株间差异显著,而株内变异较小。在白刺天然群体内,果序性状差异极为显著,其中不乏果序重突出的单株。中选优株B12、B19等的平均果序重可达8．260g和8．271g,分别比对照高出6．86倍、6．87倍;比39个中选优株的平均值超出1．26倍、1．29倍。尽管白刺株内果序重变幅较大,但B12、B19的果序重最小值仍远远高出对照,甚至分别高出39株平均值79％和66％。由于与果序重密切相关的每序核果数与单果重等单果性状相对独立,因此从果用型白刺开发利用角度考虑,与产量相关更为紧密的果序重应该作为白刺优株选择以及亲本选择的主要依据。     

Influence of Sociocultural Factors and Acceptance of Creationism in the Comprehension of Evolutionary Biology in Freshman Brazilian Students

The creationist movements in Brazil, although considered weak, are on the increase. The Brazilian legislation neither imposes any objection in teaching evolution nor obliges the teaching of creationism as an alternative to evolution in science classes. Furthermore, it allows the optional teaching of religion at schools. The aim of the present study was to evaluate the knowledge regarding biological evolution in freshman students from a Brazilian university. Such knowledge was related to sociocultural factors such as their parental education level, the type of high school the student graduated from (private or public school), their philosophical/religious position as well as the acceptance of creationism as an alternative to evolution. Among those factors, the latter two showed significant differences, in which the higher averages belonged both to the atheistic students and to those who do not accept creationism as an alternative to evolution.     

Computational simulation of the statistical properties of unfolded proteins

A simple Monte Carlo method was used to generate ensembles of simulated polypeptide conformations that are restricted only by steric repulsion. The models used for these simulations were based on the sequences of four real proteins, ranging in size from 26 to 268 amino acid residues, and included all non-hydrogen atoms. Two sets of calculations were performed, one that included only intra-residue steric repulsion terms and those between adjacent residues, and one that included repulsion terms between all possible atom pairs, so as to explicitly account for the excluded volume effect. Excluded volume was found to increase the average radius of gyration of the chains by 20-40%, with the expansion factor increasing with chain length. Contrary to recent suggestions, however, the excluded volume effect did not greatly restrict the distribution of dihedral angles or favor native-like topologies. The average dimensions of the ensembles calculated with excluded volume were consistent with those measured experimentally for unfolded proteins of similar sizes under denaturing conditions, without introducing any adjustable scaling factor. The simulations also reproduced experimentally determined effective concentrations for the formation of disulfide bonds in reduced and unfolded proteins. The statistically generated ensembles included significant numbers of conformations that were nearly as compact as the corresponding native proteins, as well as many that were as accessible to solvent as a fully extended chain. On the other hand, conformations with as much buried surface area as the native proteins were very rare, as were highly extended conformations. These results suggest that the overall properties of unfolded proteins can be usefully described by a random coil model and that an unfolded polypeptide can undergo significant collapse while losing only a relatively small fraction of its conformational entropy.     

The origin of elementary units of multicellularity and development of a spatial organization of cell layers

The concept of the elementary unit of multicellularity, the histion, which also serves as a morphofunctional unit of cell layers, is introduced. Histions are cell groups formed as a result of division of labor between cells. Cell layers are regarded as regular cell networks (lattices) formed through polymerization of histions. The theory constructed based on this concept allows the composition and structure of a multitude of histions to be calculated; their development to be quantified; and families of topological and geometrical models for the histoarchitecture of cell layers to be constructed, visualized with computer programs, and experimentally verified. In addition, this model can predict previously unknown topological variants of the histoarchitecture of epithelial tissues, as well as their presence in normal development and pathology.     

A possible involvement of glutathione in the detoxication of sulfite

Inorganic sulfite may be detoxified by conversion to S-sulfocysteine. We demonstrate this conversion by a series of enzyme-catalyzed steps as follows. Inorganic sulfite reacts with glutathione disulfide by a thiol transferase catalyzed reaction as previously demonstrated. The S-sulfoglutathione formed is then converted by gamma-glutamyltranspeptidase to S-sulfocysteinylglycine and the latter finally hydrolyzed to S-sulfocysteine by a renal dipeptidase. S-Sulfoglutathione is a substrate for gamma-glutamyl-transpeptidase as effective as glutathione itself. Furthermore, S-sulfocysteinylglycine is cleaved as efficiently as cysteinylglycine by a renal dipeptidase at high substrate concentrations but somewhat less efficiently at low substrate concentrations.     

The effect of oxygen on fatty acid composition of soil micromycetes

The aim of this work was to describe changes in fatty acid profiles of fungi growing under artificial conditions of oxygen depletion. In total, 133 fungal strains belonging to eight orders were isolated from cattle impacted soils and tested. The analysis of the ten most frequent fatty acids revealed significant shift in fatty acids composition as a result of decreasing oxygen level. Taxonomic- as well as aeration-dependent changes in the amounts of fungal biomarker fatty acids (18:1ω9 and 18:2ω6,9) were found. Therefore, the ratio of these two fatty acids could be considered as an indicator of anaerobic, microaerobic or aerobic conditions in soil. Moreover, fatty acid-based estimation of fungal biomass in soils should be performed as a sum of both biomarker fatty acids and with respect to the soil characteristics as well as to the composition of fungal community.     

The role of cytokines in the regulation of ocular autoimmune inflammation

The eye is a unique place for the development of an immune response. Beyond the usual mechanisms of immune restraint, the eye evolved with its exclusive mechanisms such as anterior chamber associated immune deviation. Therefore, immune-mediated inflammation in the eye does not develop at the same pace as in other sites of the body. Here we will address such peculiarities as they regard to ocular autoimmunity, using the experimental autoimmune uveitis as a model to understand the participation of cytokines in the process of aggression against the eye, as well as their immunoregulatory role.     

Cryopreservation of gametes and embryos of non-domestic species.

Many species of mammals are threatened or endangered. Methods of assisted reproduction that are being used with increasing frequency to produce offspring of domestic animals and humans are often viewed as offering innovative ways to reproduce non-domestic species as well. Uncounted millions of live young of domestic or laboratory species have been produced from gametes and embryos stored at -70 degrees C or below, sometimes for as long as 25 to 35 yrs. Such methods of cryopreservation are now being applied with increasing frequency and urgency to preserve gametes and embryos of non-domestic and threatened species to establish "genome resource banks" or "frozen zoos." But levels of success to produce live young from such cryopreserved gametes or embryos vary considerably from species to species, as well as from individual to individual. It is sometimes thought that differences among species in fundamental characteristics of their gametes may determine the efficacy of cryopreservation and the production of live young. However, it may not be that ineffective cryopreservation is responsible for low success rates. Rather, the limiting factor may be insufficient information and knowledge of the most basic reproductive biology of such non-domestic species. Even standard methods of cryopreservation may be completely adequate to act as a "temporary" expedient to preserve germplasm of non-domestic species to permit time to acquire a fuller understanding of the biology and behavior of non-domestic species.