l-Aspartate was found to replace l-asparagine in the protective action from acid inactivation of l-asparaginase (EC 3.5.1.1) produced by Escherichia coli A–1–3 and at the same time to inhibit the proteolytic inactivation by α-chymotrypsin.
l-Asparaginase changed in its chromatographic properties in the presence of l-aspartate and became to be absorbed on the CM Sephadex column.
The sedimentation patterns of l-asparaginase at pH 3.5 were identical either in the presence or absence of l-aspartate, showing partial dissociation. But the reversibility to the active state was observed only in the enzyme dissolved in the solution containing l-aspartate.
l-Aspartate did not prevent the enzyme either from the dissociation into subunits or from decrease in the activity by urea.
High concentration of l-aspartate was shown to inhibit the l-asparagine hydrolysis reaction.
l-Aspartate was suggested from ORD measurements to cause changes in the higher structure as well as the ionic properties or proteolytic inactivation.
This study used molecular dynamics (MD) simulation to investigate the passage of water molecules through a composite graphene/Au nano-nozzle. Our focus was on the degree to which system temperature, extrusion speed, and nozzle diameter affect jet dynamics and the associated transient phenomena. Our findings show that high pressure and spatial confinement cause the nanojet from a small nozzle diameter (1.0?nm) to bend and twist, whereas the jets from a nozzle with a diameter of 1.5?nm present columns of greater stability. At 100?K, the H2O nanojet froze at the outlet of the nozzle in the form of condensed icicles. At 500?K, the H2O nanojet formed a loose spray and gaseous clusters. High extrusion speed of 55.824?m/s produced recirculating flow downstream from the nanojet with the appearance of an erupting volcano, which further prompted the jet column to thicken. Lower extrusion speeds produced jets with flow velocity insufficient to overcome the capillary force at the outlet of the nozzle, which subsequently manifests as unstable fluctuations in the flow rate.
HIGHLIGHTS
Water molecules through a composite graphene/Au nano-nozzle forming a nanojet is investigated.
High pressure and spatial confinement cause the nanojet from a small nozzle diameter (≤1.0?nm) to bend and twist.
High extrusion speed (≧55.824?m/s) produced recirculating flow downstream from the nanojet.
Figure abstract: Schematic of the H2O nano-jet through a nano-nozzle of graphene/Au
Inmunoglobulin isolated from human sera, be it by the cryo-alcohol, rivanol, multi membrane electrodecantation or polyethylene glycol process, alvays contains denatured material. This may result from the influence either singly or in combination, of acme of the follwing factors:
inefficiency of the purification procedure;
surface denaturation;
imperfect freeze-drying of the final product; and
factors yet unknown vhich cause alteration in the immoglobulins or other protein components not ellminated by the purification procedures.
Abstract It has been shown by many workers that nucleotides containing an ap methylene link have interesting biochemical properties compared to those containing an αβ 0x0 linkage.1 In our laboratory af3 methylene thymidine triphosphate has been shown to be a more powerful inhibitorof thymidine kinase than thymidine triphosphate but a weaker inhibitor of ribonucleotide reductase and cytidine deaminase. We have been interested in examining the properties of the af3 imido analogue. Several routes to prepare the unknown ap imidothymidine triphosphate were unsuccessfully tried:
Reaction of 3′-O-Acetylthymidine with the tributylammonium salt of dicyclohexylcarbodiimide.
Reaction of 5′-O-tosylthymidine with the tributylammonium salt 3 of imidodiphosphoric acid in hot dimethylacetamide.
Ecological risk actually refers to two separate things. First, risk to the environment as a result of human activity. Contaminated sites are an example. Second, risk to the biota—flora, fauna, and people—as a result of environmental hazards. Geophysical risk arising from natural hazards is an example. Risk is a combination of likelihoods and consequences. This article examines methods used to quantify the consequences. At the general level, such methods are linked to the methods used to quantify the likelihoods and thus to quantify the risks. It is possible to use the existing frameworks of risk management, health risk assessment, and ecological risk analysis to develop a risk management framework that is suitable for ecological risk assessment. The framework consists of the following steps:
Determine concernsby using risk assessment techniques for various scenarios.
Identify the consequences by systematically identifying hazards.
Undertake calculations by using relevant models.
Evaluate certainties, uncertainties, and probabilities involved in the calculations of the vulnerability and of the exposure.
Compare with criteriato assess the need for further action.
Determine and act on options to control, mitigate, and adapt to the risk.
Riassunto L'A. ha studiato l'embriogia della Vinea difformis Pourr. ed ha potuto stabilire che:
l'archisporio è pluricellulare e possono svilupparis talvolta pi[ugrave] cellule madri;
normalmente solo una cellula madre arriva a maturità;
delle quattro megaspore solo una è fertile e precisamente la pi[ugrave] calazale;
lo sviluppo del gametofito è del tipo Normale cioè Monomegasporiale con oangio emisporiale.
Ha inoltre risontrato una anomalia di sviluppo constituita da un gametofito binucleato abnorme per ritardo delle divisioni nucleari cispetto all'acerescimento che è quello di un gametofito ottonucleato. 相似文献
Using a total of 43 craneological data obtained from any of 73 vicugna and 25 alpaca skulls, three problems were analyzed:
Identification of skulls
Taxonomic situation of the vicugna
Origin of the alpaca.
For rapid identification of New World cameloid skulls it is recommended to use the condilobasal length, the length to heigth ratio and the presence of the Fissura nasolacrimalis. Some characteristics of the skulls considered essential for the evaluation of domestication processes exclude the vicugna from the alpaca's ancestors. 相似文献
In Fortführung seiner Untersuchungen über neotropische Acanthocinini veröffentlicht der Verfasser hiermit Beschreibungen von folgenden neuen Gattungen:
Nyssodrysilla nov. gen. mit N. irrorata (Melzer) aus Brasilien als Generotype, N. viliata (Melzer), comb, nov., aus Brasilien und N. lineata nov. spec, aus Peru.
Nyssodrysola nov. gen. mit N. stictica nov. spec. aus Peru als Generotype.
Sciadosurus nov. gen. mit S. albobrunneus nov. spec. aus Peru als Generotype.
Acarinozineus nov. gen. mit A. striatus nov. spec. aus Peru als Generotype und A. spinicornis nov. spec, aus Mexiko.
Alcathousites nov. gen. mit A. chaclacayoi nov. spec. aus Peru als Generotype.
Xylergatina nov. gen. mit X. pulcher (Lane) aus Peru als Generotype.
Xylergatoides nov. gen. mit X. asper (Bates) aus Brasilien und Argentinien als Generotype.
Ferner werden revidiert die Gattungen:
Xylergates Bates, Generotype X. lacteus (Bates), mit Beschreibung der beiden neuen Arten X. elaineae aus Peru und X. dorotheae aus Britisch‐Guayana.
Chaetanes Bates, Generotype C. setiger (Bates), mit Beschreibung der drei neuen Arten C. costulatus aus Peru, C. nigrobasalis aus Brasilien und C. apicalis aus Französisch‐Guayana.
Wo es erforderlich ist, sind Bestimmungstabellen gebracht und die Arten abgebildet.
The nutritional values of nonessential amino acids as the nitrogen source in the crystalline amino acid diet for the chick growth were examined. The nitrogen of the nonessential amino acids in the basal diet for chick was substituted for a nonessential amino acid to be tested on the nitrogen base. The experimental methods were the same as in the evaluation of the nutritional value of d-amino acids previously reported. Nonessential amino acids were classified into four groups.
Very useful nitrogen source: Glutamic acid, Aspartic acid
At the end of experiment chicks were killed and the concentration of free amino acids in the serum were measured. The concentration of glycine and serine in the serum increased when glycine was tested, but that of serine in the serum only increased when serine was tested. This result suggested the pathway from glycine to serine was fast and the opposite one was very slow. 相似文献
Gallic acid acts as a precursor molecule to synthesize various tannin molecules. These are plant polyphenols and were proved to be good anti-oxidant, anti-cancerous, anti-inflammatory, anti-microbial compounds. In order to fully exploit prominent biological activities of specific tannins and to develop tannin-based new medicines, it is necessary to obtain their pure preparations with an aim of high yield and specificity. In the present study, gallic acid is synthesized by the hydrolysis of tannic acid using a microbial based transformation process. The microorganism was isolated and identified. The ability of the isolated microorganism to covert tannic acid into gallic acid was determined by HPLC and enzyme production.
Highlights
The present investigation signifies the role of Enterobacter spp. in various processes:
??To synthesize gallic acid (a precursor for food oxidant such as propyl gallate) and a bacteriostatic antibiotic (trimethoprim).
??To protect the environment from tannery’s discharge through the process of biodegradation.
??To reduce the toxicity of tannins in animal feed.
L-Asparaginase (EC 3.5.1.1) from Escherichia coli A–l–3 was acetylated using acetic anhydride as a modifying chemical. The fully acetylated L-asparaginase retained 60% of the activity of the unmodified L-asparaginase.
The acetylated L-asparaginase hydrolyzed D-asparagine and L-glutamine as well as L-asparagine in the same ratio as the unmodified L-asparaginase did.
However, the effects of pH on the activity of the acetylated L-asparaginase showed very interesting differences from that of L-asparaginase. On the other hand, both L-asparaginase and the acetylated L-asparaginase exhibited similar pH activity curves on L-glutamine hydrolysis.
The acetylated L-asparaginase was found to become more stable against acid or heat in the presence of L-aspartate than in its absence in the same manner as L-asparaginase was.
The concentration and composition of dissolved constituents in water, determine its quality for irrigation. Quality of water is important consideration in any appraisal of salinity or alkali conditions in an irrigated area. The characteristics of an irrigation water that appear to be most important in determining its quality are:
Total concentration of soluble salts.
Relative proportion of sodium to other cations.
Concentration of boron or other toxic elements.
Under certain conditions, the bicarbonate concentration as related to the concentration of calcium plus magnesium.
The total concentration of soluble salts in irrigation waters can be adequately expressed for purposes of diagnosis and classification in terms of electrical conductivity. Irrigation waters that have been used successfully for a considerable time have conductivity values less than 2,250 micro mhos/cm. Waters of higher conductivity are used occasionally, but crop production, except in unusual situations, has not been satisfactory. 相似文献
Stearoyl-CoA desaturase-1 (SCD1) catalyzes the synthesis of monounsaturated fatty acids and is an important regulator of whole body energy homeostasis. Severe cutaneous changes in mice globally deficient in SCD1 also indicate a role for SCD1 in maintaining skin lipids. We have generated mice with a skin-specific deletion of SCD1 (SKO) and report here that SKO mice display marked sebaceous gland hypoplasia and depletion of sebaceous lipids. In addition, SKO mice have significantly increased energy expenditure and are protected from high fat diet-induced obesity, thereby recapitulating the hypermetabolic phenotype of global SCD1 deficiency. Genes of fat oxidation, lipolysis, and thermogenesis, including uncoupling proteins and peroxisome proliferator-activated receptor-γ co-activator-1α, are up-regulated in peripheral tissues of SKO mice. However, unlike mice globally deficient in SCD1, SKO mice have an intact hepatic lipogenic response to acute high carbohydrate feeding. Despite increased basal thermogenesis, SKO mice display severe cold intolerance because of rapid depletion of fuel substrates, including hepatic glycogen, to maintain core body temperature. These data collectively indicate that SKO mice have increased cold perception because of loss of insulating factors in the skin. This results in up-regulation of thermogenic processes for temperature maintenance at the expense of fuel economy, illustrating cross-talk between the skin and peripheral tissues in maintaining energy homeostasis.Obesity is a multifactorial disease stemming from a combination of genetic, dietary, and lifestyle factors and the interaction between these components (1–3). The microsomal enzyme, stearoyl-CoA desaturase-1 (SCD1),3 is a critical control point in the development of metabolic diseases, including obesity and insulin resistance. SCD1 catalyzes the conversion of saturated fatty acids, such as palmitate (16:0) and stearate (18:0), into their Δ-9 monounsaturated products, palmitoleate (16:1 n-7) and oleate (18:1 n-9), respectively. Mice lacking the SCD1 enzyme because of a global deletion of the Scd1 gene (GKO) are lean and protected from diet-induced and leptin deficiency-induced obesity. These mice have a marked increase in energy expenditure and almost complete protection from high fat diet-induced weight gain and glucose intolerance (4–10).Because SCD1 is expressed in multiple tissues, including liver, brown and white adipose tissue, skeletal muscle, and skin, it has been difficult to determine the relative contributions of these tissues to the dramatically altered metabolic phenotypes of GKO mice. Studies using antisense oligonucleotide-mediated approaches to knock down Scd1 expression have reported protection from diet-induced weight gain and hepatic insulin resistance upon hepatic SCD1 inhibition (11–13). However, whereas the liver is a major target of these antisense oligonucleotides, they have also been reported to affect expression of target genes in adipose tissue (13, 14) and possibly other organs (15). Using Cre recombinase-mediated inhibition of hepatic Scd1, we recently reported that chronic deletion of SCD1 specifically in liver does not protect mice from high fat diet-induced obesity (16), suggesting that extra-hepatic tissues may play a more prominent role in the increased energy expenditure phenotype of global SCD1 deficiency (16).In addition to their hypermetabolic phenotype, global SCD1 deficiency also elicits marked cutaneous phenotypes, including dry skin, alopecia, and sebocyte hypoplasia (7, 17, 18). Given the severity of this skin phenotype in GKO mice, we sought to establish a specific role for SCD1 in the skin. In this study, we used the Cre-lox system to generate mice with a skin-specific deletion of SCD1 (SKO). We report here that SKO mice have a severe paucity of lipid-enriched sebocytes in the skin, resulting in dry skin, alopecia, and marked alterations in levels of key skin lipids. Unlike mice with global or liver-specific deletion of SCD1 (7, 16), SKO have an intact hepatic lipogenic response to dietary stimuli. However, deletion of skin SCD1 completely recapitulates the increased energy expenditure phenotype of GKO mice (7) and protects SKO mice from high fat diet-induced obesity, hepatic steatosis, and glucose intolerance. Elevation of genes encoding for cold-inducible factors, including peroxisome proliferator-activated receptor γ co-activator-1α (Pgc-1α) and uncoupling proteins (Ucps) in brown and white adipose tissue and skeletal muscle of SKO mice, suggests up-regulation of thermogenic processes for maintenance of core body temperature in SKO mice. Furthermore, the hypermetabolic phenotype of SKO mice, coupled with the loss of insulating factors in the skin, results in severe cold intolerance in SKO mice that is ameliorated by prior feeding with a high fat diet. To the best of our knowledge, this study represents the first example of skin-specific deletion of a lipogenic enzyme resulting in profound changes in systemic energy metabolism. These data elucidate an as yet under-appreciated role for skin SCD1 in triggering the altered metabolic phenotypes caused by global SCD1 deletion. 相似文献
Summary The Author studies the action of the presence of the ear and its parts in the growth of the stem and in the value of the water of traspiration and of assimilation in the higher leaf. The stet shows:
A removed ear, not yet mature, exerts a depressing effect upon the development of the stem and ucon the leaf's functions.
The threads and the pistils removed inhibit the enlongament of the stem and alter the functions of leaves.
Maturing seeds removed cause trubles on the function of the vegetative organ.
This phenomen is due to the presence of an hormonical substances elaborated in the riproduction's orgas, which are considerated the centre of functional correlation. 相似文献
Research into the visual shape discrimination abilities of compound‐eyed animals has almost exclusively been limited to insects, the crustaceans having been virtually ignored. The two groups have many dissimilarities, having primarily adapted in different habitats to different lifestyles. Differences may exist in visual systems and visually mediated behavior.
Fiddler crabs (Uca pugilator), without training, differentially approached dissimilar silhouettes presented simultaneously, demonstrating visual discrimination between stationary, geometric shapes of equal‐area. The strength of response was ordered hierarchically: vertical rectangle, horizontal rectangle, triangle, square, circle.
Basic geometric shapes were used to facilitate replication and comparison with research findings from other species.
