Development of novel nanocomposite membrane for water purification.

In the area of water purification, nanotechnology provides efficient removal of pollutants and germs. Electrospun nanofibers membrane has a potential for water purification due to its high large surface area, and good mechanical strength. In the present study, PAMAM dendrimers composite nylon-6 nanofibers membrane was prepared by crosslinking method using glutaraldehyde. Modified membrane has drastically improved water purification efficiency. Further, the efficacy of the modified membrane can be renewed by mere exposure of the saturated membrane with the solution having acidic pH. The modified membrane can be used as an effective tool for water purification.

Sequential changes in mucosal immunity after hemorrhagic shock.

Immunoinflammatory responses after shock and major trauma are characterized by an early hyperinflammatory response and later by compensatory anti-inflammatory host mediator production. This late phase is associated with depressed immune function that has been causally linked with post-traumatic infectious complications and late organ failure. Gut barrier failure is noted in this setting and may be an important source of nosocomial infections and organ failure. Secretory immunoglobulin A (sIgA) is the predominant immunoglobin at mucosal surfaces and is difficult to quantify in luminal secretions. Attempts to normalize sIgA concentrations may not be accurate and/or may not be applicable in vivo. A method using mucosal immunization with cholera toxin (ChT) to normalize gut sIgA levels was used to assess serial changes in sIgA after hemorrhagic shock (HS) in rodents. Total and anti-ChT sIgA levels were highly variable in both HS and sham animals. However, when normalized using the specific anti-ChT/total sIgA ratio, differences were clearly evident. This ratio was depressed between 3 and 10 days post-HS. The specific anti-ChT/total sIgA ratio is a reliable index of secretory antibody at gut luminal surfaces. Impaired mucosal immune function occurred in a time frame consistent with development of late nosocomial infections. This may be important mechanistically in the development of these infectious complications.

Hemorrhagic shock impairs mucosal immunity to gut-derived antigens.

Secretory immunoglobulin A (sIgA) is the principal antibody protecting against pathogens in the respiratory tract and other mucosal surfaces. Nosocomial pneumonias are frequent after injury and critical illness and are often due to enteric pathogens. The aim of this study was to assess the relative effect of hemorrhagic shock (HS) on mucosal immunity at intestinal and respiratory mucosal sites. Fisher rats were immunized intragastrically with dinitrophenylated (DNP) Pneumococcus (Pn). Three weeks later, animals were subjected to sham treatment or HS. The animals were then rechallenged with DNP-Pn 1 or 3 days later. Animals were sacrificed 7 days later, and bronchoalveolar and gastric lavage was performed. Total and anti-DNP-specific sIgA were quantitated from these secretions by enzyme-linked immunosorbent assay. There was a significant decrease in DNP-Pn-specific sIgA at 72 hours after HS, which was not present in animals at 24 hours after HS. This was most profound in bronchoalveolar lavage specimens. We conclude that impaired mucosal defense against gut-derived antigens after HS may be important mechanistically for the development of posttraumatic pneumonia and other mucosally related infectious complications.

Stereochemical course of phospho group transfer by human prostatic acid phosphatase.

The stereochemical course of the phospho transfer catalyzed by homogeneous human prostatic acid phosphatase was investigated using 31P nuclear magnetic resonance spectroscopy. Transphosphorylation from phenyl-(R)-[15O, 17O, 18O]phosphate to (S)-propane-1,2-diol occurs with overall retention of configuration at phosphorus. This stereochemical result is consistent with the interpretation that the hydrolysis of substrates by this enzyme proceeds by way of a covalent phosphoenzyme intermediate. Conditions for optimizing phospho transfer by this and related acid phosphatases have also been explored.

Stereochemistry of phospho transfer catalyzed by bovine liver acid phosphatase.

The hydrolysis of phosphoric monoesters by acid phosphatases is thought to proceed via the formation of a phosphoenzyme intermediate, but no stereochemical evidence exists on this point. We have carried out the transphosphorylation from phenyl (R)-[16O, 17O, 18O] phosphate to (S)-propane-1,2-diol in the presence of homogeneous bovine liver acid phosphatase, and have found that the reaction proceeds with greater 90% overall retention of configuration at phosphorus. This stereochemical course of phospho transfer during the enzyme-catalyzed reaction of the phosphoric monoester is consistent with a double displacement mechanism in which each step proceeds with inversion of the stereochemistry at phosphorus, and is similar to the behavior of the bacterial alkaline phosphatase.

A clinical assay for prostatic acid phosphatase using choline phosphate as a substrate: comparison with thymolphthalein phosphate.

We describe an assay method using choline O-phosphate as a substrate for the measurement of serum prostatic acid phosphatase as an aid in the diagnosis of prostatic cancer. Choline phosphate is hydrolyzed by homogeneous prostatic acid phosphatase, and it is also hydrolyzed by an acid phosphatase present in the serum of prostatic carcinoma patients. In contrast, serum samples from apparently healthy persons do not exhibit any significant choline O-phosphate phosphatase activity. There is a correlation of 98% (n = 46) between choline O-phosphate phosphatase activity and typical measurement for prostatic acid phosphatase activity carried out using thymolphthalein monophosphate as the substrate. The new method appears to be as accurate as colorimetric methods based on thymolphthalein phosphate as a substrate. Although not as sensitive as immunologically based methods, the present technique for measuring prostatic acid phosphatase activity using choline phosphate as a substrate is economical and relatively simple.

An essential carboxylic acid group in human prostate acid phosphatase.

Treatment of homogenous human prostatic acid phosphatase (orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2) with low concentrations of Woodward's reagent K (N-ethyl-5-phenylisoxazolium-3'-sulfonate) leads to a rapid loss of enzymic activity. The rate of inactivation of the enzyme is reduced in the presence of the competitive inhibitors phosphate and L-(+)-tartrate, but not in the presence of non-inhibitory D-tartrate. Measurement of the ethylamine produced upon hydrolysis of enzyme modified in the presence of D- and of L-tartrate permitted the quantitative estimation of the number of carboxylic acid residues at the active site. The data indicate that two carboxyl groups per (dimeric) enzyme molecule are essential for catalytic activity. It is proposed that one function of the active site carboxyl group may be to protonate the leaving alcohol or phenol portion of the phosphomonoester substrate during the formation of the covalent phosphoenzyme intermediate.

Dimeric nature and amino acid compositions of homogeneous canine prostatic human liver and rat liver acid phosphatase isoenzymes. Specificity and pH-dependence of the canine enzyme.

Two isoenzymes of rat liver acid phosphatase (orthophosphoric-monoester phosphohydrolase (acid optimum) EC 3.1.3.2) have been purified to homogeneity, at least one of these for the first time. Both of the rat liver isoenzymes have identical specific activities towards p-nitrophenyl phosphate. Molecular weights of the native enzymes are 92 000 for rat liver isoenzyme I and 93 000 for isoenzyme II, while the subunit molecular weights are 51 000 and 52 000 respectively. Data on substrate specificity and pH dependence are presented for the homogeneous canine prostatic enzyme, which is also isolated as a dimeric enzyme of (native) molecular weight 89 000. Carbohydrate analysis data are presented for canine prostatic acid phosphatase and it is further noted that both isoenzymes of rat liver acid phosphatase are also glycoproteins. The amino acid compositions of the two rat liver isoenzymes are presented together with those of the similar dimeric acid phosphatase of human liver and of canine prostate. Comparison of these results with published data for the amino acid composition of human prostatic acid phosphatase shows substantial similarities. However, significant differences are seen in the amino acid composition of rat liver acid phosphatase isoenzyme I as compared to a previous literature report. Most notably, 17 histidine residues are found per mol of isoenzyme I and 18 for isoenzyme II.

Selective purification of tartrate-inhibitable acid phosphatases: rapid and efficient purification (to homogeneity) of human and canine prostatic acid phosphatases.

We describe the synthesis of a long-chain monoamide derivative of L(+)-tartaric acid and its attachment to Sepharose 4B. Procedures are then described for use of this material in purifying human prostatic and (for the first time) canine prostatic acid phosphatases to constant specific activity and electrophoretic homogeneity. Depending on sample size, such purification is possible in one step, and is clearly faster and more efficient than are previously described methods. These materials and procedures have significant potential in studies of the comparative biochemistry and clinical chemistry of tartrateinhibitable acid phosphatases.

Preparation of homogeneous human prostatic acid phosphatase using concanavalin A-sepharose 4-B.

A simple, rapid and efficient procedure is presented for the purification of human prostatic acid phosphatase (orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2) to homogeneity. The method employs two steps suitable for use with large quantities of material, followed by chromatography on concanavalin A-Sepharose as its sole column step. The procedure also permits the recovery of purified enzyme in higher yields than earlier methods.

Wheat embryo ribonucleates. VIII. The presence of 7-methylguanosine 'cap structures' in the RNA of imbibing wheat embryos.

1. By imbibing wheat embryos in media that contain methyl-labelled methionine, it is possible to label both terminal and nonterminal 7-methylguanosine constituents in NaCl-insoluble (2.5 M, 0 degrees C) RNA (iRNA). 2. Most of the 7-[Me-14C]methylguanosine in wheat embryo i[Me-14C]RNA is present in nonterminal positions of polynucleotide chains, probably in ribosomal RNA. 3. By passage through a column of oligo-dT-cellulose, it is possible, to show that most of the 7-[Me-3H]methylguanosine in a 'bound' fraction of i[Me-3]RNA from imbibing wheat embryos is present in terminal 'cap' structures, probably in messenger RNA. 4. Although most of the 7-[Me-3H]methylguanosine in the 'unbound' (to oligo-dT-cellulose) fraction of i[Me-3H]RNA was present in nonterminal positions, there was also a highly significant fraction of 7-[Me-3H]methylguanosine in terminal 'cap' structures. Although it will be a subject of continued investigation, possible reasons why a large fraction of the total 7-[Me-3H]-methylguanosine was present in the 'unbound' fraction, in this present study, are a subject of discussion. 5. Careful analysis failed to reveal the presence of any N6,O2'-di[Me-3H]methyladenosine in the 'unbound' fraction of i[Me-3H]RNA. 6. Factors that might influence the binding of 'cap' oligonucleotides to DEAE-cellulose are the subject of a brief discussion.