Neutral End-products Research Articles

Molecular Epidemiology genes detection of Klebsiella pneumoniae Clinical Isolates from the Adult Patients with Comorbidities in Baghdad hospitals

Background Klebsiella species is one of the most worldwide opportunistic pathogens in the world that cause infections at multiple sites like lung, urinary tract, bloodstream, wound or surgical site, and brain. Klebsiella pneumoniae has many types of virulence factors that give the bacteria the ability to invade the host and cause infections. Methods A total of (105) human clinical samples were collected from different patients with different cases. Klebsiella pneumonia were isolated from 30 samples. The bacteria were identified by biochemical tests and certified by using VITEK 2 system and genetically by amplify using PCR for 16 rRNA gene. One of the Klebsiella pneumoniae virulence factors is the capsule that is responsible for the macrophage resistance and its also responsible for serotype. So to confirm the strains isolated, PCR Gene detection of, MagA, K2A, RmpA, and Kfu, where (magA, k2A, rmpA, kfu) gens are responsible for capsule synthesis of Klebsiella pneumonia have been done. Results There were 30 strains of Klebsiella pneumoniae were identified. Epidemiological studies show that infections are preceded by gastrointestinal colonization, with the gastrointestinal tract being the most important reservoir for transmission. The primary bacterial isolates were identified based on their cultural, microscopic, and biochemical traits. The API system (API 20E) and VITEK 2 systems were used to confirm the identity of the bacterial isolates. Colony morphology revealed that Klebsiella pneumonia was Gram-negative, non-motile, microscopic straight rods grouped singly or in pairs. Biochemical tests showed that neutral end products prevailed over acidic end products, with Klebsiella producing negative results for indole. The Kligler Iron Agar (KIA) test showed that Klebsiella isolates changed the color of the slant and butt, producing an acidic slant and acid butt, along with gas production. The urease test for Klebsiella distinguishes between Enterobacter and Klebsiella isolates, as Klebsiella can manufacture the urease enzyme. The indole test distinguishes K. pneumonia from K. pneumonia from K. mobiliz. The API 20E system was used for biochemical testing, and the VITEK 2 system was used for identification. The VITEK 2 system was used to test for biochemical and antibiotic susceptibility, and the results supported the findings from morphological and biochemical analyses. PCR amplification was used for molecular detection, and all nine isolates tested positive for the magA and k2A genes. The ferric iron uptake system gene (kfu) and the extracapsular polysaccharide synthesis regulator gene (rmpA) were amplified using specific primer pairs. The VITEK 2 system demonstrated promising outcomes for K. pneumoniae identification. However, standard diagnostic methods are costly and time-consuming. Conclusions Navigating the complex landscape of infectious diseases, collaborative research projects have become indispensable in unraveling the mysteries surrounding pathogens. The project in Baghdad, having stood as a shining example of such collaboration, provided valuable insights into the identification, characterization, and molecular aspects of Klebsiella pneumoniae strains. The findings, have not only contributed to the scientific community's understanding of bacterial infections but also paved the way for enhanced strategies in diagnosis and treatment.

Acetoin synthesis acquisition favors Escherichia coli growth at low pH.

Some members of the family Enterobacteriaceae ferment sugars via the mixed-acid fermentation pathway. This yields large amounts of acids, causing strong and sometimes even lethal acidification of the environment. Other family members employ the 2,3-butanediol fermentation pathway, which generates comparatively less acidic and more neutral end products, such as acetoin and 2,3-butanediol. In this work, we equipped Escherichia coli MG1655 with the budAB operon, encoding the acetoin pathway, from Serratia plymuthica RVH1 and investigated how this affected the ability of E. coli to cope with acid stress during growth. Acetoin fermentation prevented lethal medium acidification by E. coli in lysogeny broth (LB) supplemented with glucose. It also supported growth and higher stationary-phase cell densities in acidified LB broth with glucose (pH 4.10 to 4.50) and in tomato juice (pH 4.40 to 5.00) and reduced the minimal pH at which growth could be initiated. On the other hand, the acetoin-producing strain was outcompeted by the nonproducer in a mixed-culture experiment at low pH, suggesting a fitness cost associated with acetoin production. Finally, we showed that acetoin production profoundly changes the appearance of E. coli on several diagnostic culture media. Natural E. coli strains that have laterally acquired budAB genes may therefore have escaped detection thus far. This study demonstrates the potential importance of acetoin fermentation in the ecology of E. coli in the food chain and contributes to a better understanding of the microbiological stability and safety of acidic foods.

PP213-MON AN APPROPRIATE METHOD TO MEASURE FRUCTAN LEVELS IN ENTERAL NUTRITION

Conclusion: Asidophilus ForteTM with prebiotics restricted facultatives in the PMEU. Neither probiotics nor prebiotics alone had this effect. The effect remained during different growth phases. Further studies are warranted for evaluating the impacts of various components of the prebiotic mixture. The supplementations could in vivo prevent bacterial overgrowth and balance the numbers of acid and neutral end-products producing facultatives, which could support food uptake.

PP214-MON 1–2,(30) FORMULA FOR SODIUM, POTASSIUM AND WATER NEEDS CALCULATION

Conclusion: Asidophilus ForteTM with prebiotics restricted facultatives in the PMEU. Neither probiotics nor prebiotics alone had this effect. The effect remained during different growth phases. Further studies are warranted for evaluating the impacts of various components of the prebiotic mixture. The supplementations could in vivo prevent bacterial overgrowth and balance the numbers of acid and neutral end-products producing facultatives, which could support food uptake.

Dualistic acidic and neutral glucose fermentation balance in small intestine: Simulation in vitro

Intestinal microbes live in diminished or deprived oxygen conditions. Facultative anaerobic bacteria of the family Enterobacteriaceae ferment glucose in the gut using two main pathways: mixed acid and neutral fermentations. The aim of the present study was to clarify the roles of these fermentations in an in vitro model. Acid-producing Escherichia coli ATCC 25922 and neutral end-products producing Klebsiella mobilis ATCC 13048 were cultured in a Portable Microbe Enrichment Unit (PMEU) which permitted the selection of the gas phase in standardized conditions. In the butanediol production experiments also Klebsiella pneumoniae ssp. pneumoniae IIIa2 E111 strain was also used. Two isomers of 2,3-butanediol were observed in both aerobic and microaerobic Klebsiella cultures. During 7 h cultures both E. coli and K. mobilis grew from densities of some million up to some billions per ml. The growth was almost equal in both aerobic and microaerobic conditions. In anaerobic conditions a balance prevailed in mixed E. coli and Klebsiella cultures between the species (final pH was 5.8–6.1), whereas in aerobic conditions the klebsiellas were favoured, and the pH rose up to about 8.5 (in 20 h) as in pure Klebsiella cultures. In microaerobic Klebsiella cultures the final pH varied between 6.7 and 7.5. In mixed cultures the growth yields of both bacteria equalled those of the separate pure cultures indicating mutual benefits of the co-existence. Apparently E. coli produced a set of organic acids, which lowered pH. Klebsiellas increased the pH up to 2 units probably due to acid conversion in anaerobic conditions to ethanol. We propose that the balance of acid and ethanol as well 2,3-butanediol fermentations contributes to the small bowel pH regulation, which also aids the host in the nutrient uptake in the small intestine.

Chemistry of Protonated Species in Gaseous Environments

AbstractFor Abstract see ChemInform Abstract in Full Text.

Chemistry of protonated species in gaseous environments

AbstractAn overview is presented of gas‐phase studies on the structure and reactivity of protonated species from the authors' research. Specific problems have been addressed operating in different gaseous environments, either in radiolytic systems at atmospheric pressure, enabling the NMR characterization of the neutral end products of gas phase ion–molecule reactions, or in low‐pressure FT‐ICR mass spectrometry, where ions can be trapped and characterized by their reactivity or spectroscopic features. Proton transfer reactions have revealed the role of competing acidic sites leading to biologically relevant C7H7O. radical species and of competing basic sites in substituted benzenes. Proton transfer reactions have also been used as a tool to form elusive cations, e.g. c‐C3H, modulating the reaction energetics, and to unveil the structure and occurrence of degenerate isomerization processes within the benzenium ion. Copyright © 2004 John Wiley & Sons, Ltd.

The protonation of gaseous cyclopropane.

The protonation of cyclopropane by gaseous Brønsted acids of varying strength in radiolytic experiments at atmospheric pressure leads to two distinct C3H7- isomers that have been sampled by their reaction with benzene. The neutral end products, nC3H7-C6H5 and iC3H7-C6H5, arise from the electrophilic aromatic substitution reaction with the cC3H7+ and iC3H7+ ions, respectively. Their relative abundance was studied as a function of pressure, temperature, and the presence of additives in the gaseous systems; the results indicate a large extent of isomerization to the thermodynamically favored iC3H7+ from the protonation by strong acids. The presence of a kinetic barrier prevents any thermal isomerization from taking place in the time frame of 10(-8) s. In the peculiar case in which protonated benzene is the Brønsted acid, C3H7+ ions are formed in the presence of neutral benzene within the same ion - molecule complex. The ensuing reaction shows that cC3H7+ ions are formed exclusively and react in the 10(-10) s(-1) estimated lifetime of the complex. Still, such cC3H7+ ions undergo complete randomization of their hydrogen atoms; this points to a low kinetic barrier for the process. Agreement is found between the reported experimental results and updated computations of the relevant species in the C3H7+ potential energy surface.

Purification and properties of an endo‐1,4‐xylanase excreted by a hydrolytic thermophilic anaerobe, Clostridium thermolacticum

An extracellular xylanase from a thermophilic anaerobe, Clostridium thermolacticum, was purified 400-fold by ion-exchange chromatography and gel filtration. The purified enzyme had a specific activity of 31,670 nkat/mg of protein at 60 degrees C, a molecular mass of 39 kDa and a pI of 4.9. The enzyme exhibited maximal activity at 80 degrees C (1 h assay) and at pH 6.0-6.5. There was little loss of activity after 4 days at 60 degrees C and the enzyme was stable in the wide pH range 3-11. Examination of the hydrolysis products of larchwood xylan indicated that it was an endoxylanase; at the early stage of the reaction, xylose (Xyl)-containing oligosaccharides of 3-12 residues were released and after a prolonged incubation time, the neutral end-products were Xyl2 and Xyl3. Kinetic studies of the hydrolysis of xylose-containing oligosaccharides of 4-7 residues showed that the tetrasaccharide was hydrolysed more slowly than the pentasaccharide, while the calculated Km and V values for pentasaccharide and hexasaccharide were similar. The primary structures of the XylnGlcA produced by long-term hydrolysis of larchwood glucuronoxylan were determined on the basis of their carbohydrate composition, by methylation analysis and by 1H-NMR and 13C-NMR spectroscopies. These data allowed us to propose a model for the mode of action of this endoxylanase on larchwood 4-O-methylglucuronoxylan.

A review of the role of acid-base balance in amino acid nutrition.

Acid-base balance and amino acid metabolism are intimately related. Changes in acid-base balance influence the metabolic fate of many amino acids. Also, acid-base homeostasis is achieved in part by alteration of amino acid metabolism, not only in the kidney, but also in liver, muscle and splanchnic tissue. Glutamine is the primary amino acid involved in renal ammonia-genesis, a process intimately related to acid excretion. The metabolism of other amino acids, such a serine, glycine and the branched-chain amino acids, also appears to be influenced by acid-base balance. Conversely, the metabolic fate of various amino acids will influence the daily acid load experienced by the animal. Oxidation of amino acids contributes to the total acid and base load imposed on the pig. The basic (cationic) amino acids (lysine, arginine and histidine) yield neutral end-products plus a proton; sulfur (methionine and cysteine) amino acids are also acidogenic because they generate sulfuric acid when oxidized. The dicarboxylic (anionic) amino acids (aspartate and glutamate, but not asparagine and glutamine) consume acid when oxidized and thus reduce the acid load of the diet. Acid-base balance and related phenomena are discussed in the context of practical and metabolic aspects of amino acid nutrition.

Cationic aromatic silylation in the gas phase

Aromatic substitution by SiMe + 3 ions has been studied in the gas phase with an integrated approach, based on mass spectrometry and on a radiolytic technique, characterized by an extended pressure range up to 720 torr and by the actual isolation of the neutral end products, which provides positive structural information. The results demonstrate the occurrence of aromatic substitution, leading to the formation of a CSi bond, and suggest a σ-complex (Wheland intermediate) structure of the ArHSiMe + 3 adducts previously detected by ICR and high-pressure mass spectrometry. The selectivity of the silylation, e.g. k T/ k B = 3.8 ± 0.4, 14% meta and 86% para orientation in toluene, characterize the reaction, unprecedented both in the gas phase and in solution as a typical electrophilic substitution dominated by the steric requirements of the bulky SiMe 3 group, similar in many respects to aromatic alkylation by gaseous t-Bu +.

Acidic metabolites. VI 20α-isosteroids as intermediates in 20α-dihydrosteroid formation

We have previously shown that human subjects metabolize the 20β-epimer of isocortisol (11β,17,20β-trihydroxy-3-oxo-pregn-4-en-21-a1) to both 20α- and 20β-hydroxy steroid end products. In this paper we describe the synthesis of tritium labeled 20α-epimers of isocortisol and isoTHF (3α,11β,17,20α-tetrahydroxy-5β-pregnan-21-al) and their metabolic fate in humans. Both steroids yielded 20α-hydroxy urinary neutral end-products (cortols and cortolones) and no 20β-hydroxy epimers. Regeneration of 17-ketols from aldols occurred to a small extent with isoTHF, but not with isocortisol. Isocortisol and isoTHF yielded less cortoic acids than did the corresponding ketols. The results provide further evidence that in man the stereochemistry at C-20 of the end-products of corticosteroid metabolism is determined by the configuration of the aldol at C-20 prior to subsequent metabolic events.

Anaerobic Metabolism in the Free-Living Nematode Panagrellus redivivus

Under anaerobic conditions, the free-living nematode Panagrellus redivivus produces a range of acidic and neutral end products. The main acidic end product was lactate with lesser amounts of alanine, acetate, and propionate; the major neutral end product was ethanol with smaller amounts of glycerol and traces of acetoin. Apart from carbon dioxide, no other end products could be detected. During recovery from anaerobiosis, P. redivivus was found to be able to remetabolize the accumulated end products. The coproduction of ethanol and glycerol may provide a mechanism for reoxidizing mitochondrial NADH during anaerobiosis.

Purification and properties of an endo-(1→4)-β- d-xylanase from irpex lacteus (Polyporus tulipiferae)

A xylanase from Driselase (a commercial enzyme preparation), obtained from the basidiomycetes Irpex lacteus (Polyporus tulipiferae), was purified ∼32-fold by desalting on Sephadex G-25, ion-exchange chromatography on DEAE-Sepharose CL-6B and CM-Sepharose CL-6B, hydrophobic-interaction chromatography on Phenyl-Sepharose CL-4B, gel filtration on Ultrogel AcA54, and affinity chromatography on Concanavalin A-Ultrogel. The enzyme is a glycoprotein that contains 23% of sugars, mainly as glucose. Its molecular weight is 38,000 and its pI 7.6–8.0. The enzyme exhibited maximal activity at pH 4.6–5.2 and at 60°, and was completely inactivated within 30 min at 70°. The K m values for larch 4- O-methylglucuronoxylan were 2.8 (suspension in water) and 1 mg/mL (solution in 20% methyl sulfoxide). The xylanase degraded larchwood xylan to xylose, xylobiose, and xylotriose, as neutral end-products.

The Disputed Charge Account

It's between rounds in one of the longest-lasting and most impassioned battles in contemporary chemistry: the fight over where the positive charge lies on a certain seven-carbon ion, or charged molecule. In one corner stand the vast majority of participants in the fight, who believe that the positive charge simultaneously over, or shared by, several atoms of that molecule. Having just dealt a few sizable blows, this group says the fight now should be called in its favor. In the other corner stand the mere handful of remaining participants, who either cling to the notion that the positive charge behaves more conventionally, belonging to only one atom at a time, or at least insist that there not yet enough evidence to support the idea. Though it the general consensus of the community that this minority opinion has been scientifically pummeled, its most vociferous proponent, a Nobel-Prize winning chemist, shows no signs of throwing in the towel. While there have been several other chemistry controversies that also ... were carried forth because virtually only one of their participants would not give up, says one observer, there really have been no others quite like this debate over the positively charged molecule, or cation, called the 2-norbornyl cation (n6r-b6r'-n'l kat'i-an). In some ways, it ranks among the worst of debates: Its strained, often brutal discourse, for example, led at least one prominent chemist early on to quit doing research related to the issue because he didn't like the stress involved. But in other ways, it ranks among the best: It has depended on-and in some cases, redefined the state of the art in several research fields. In addition, the heart of the issue how the positive charge distributed on the 2-norbornyl cation is not a negligible question, says George A. Olah, champion of the smeared theory. The skeletal norbornyl structure is found in many of nature's terpenes [chemicals found in plant oils], Olah says. Moreover, the norbornyl cation an ionic intermediate-a charged link between the neutral starting materials and neutral end products of various chemical reactions; and some of its chemical cousins are ionic intermediates in major petrochemical reactions, says Olah, of the University of Southern California in Los Angeles. Understanding the precise behavior of the 2-norbornyl cation eventually could have implications for research on both terpenes and major industrial processes. The attempt to understand the precise behavior of the 2-norbornyl cation can be traced back to work reported in 1949 by the late Saul Winstein of the University of California at Los Angeles. Winstein was studying a chemical reaction that can start with either of two versions of the same compound: One, called the exo-norbornyl starting material, has a group of atoms (labeled A in the diagram on p. 107) substituted for a hydrogen at the carbon-2 position of norbornane in such a manner that it lies slightly above the plane formed by carbons 2, 3, 5 and 6. The other version, called the endo-starting material, also has

Effect of eight growth media upon fermentation profiles of ten anaerobic bacteria.

A study was made of the influence of eight growth media upon the fermentation end-product patterns obtained with ten species of anaerobes. Acidic and neutral end-products of fermentation were analysed by gas chromatography and the results were examined statistically by computer. Differences in end-product profile were at least as great between different media used to grow a single anaerobic species, as between different anaerobes grown in a single type of medium. When individual fermentation end-products produced by a single anaerobe species were examined statistically significant differences were found between different media for individual end-products. It is concluded that standardisation of growth medium is essential in diagnostic laboratories concerned with identification of anaerobes with the aid of gas chromatography.

Determination of pregnane-17,21-diol-20-ones in human urine.

Treatment of urine or of a urine extract with periodate followed by treatment of the acidic oxidation products with sodium bismuthate gave a mixture of neutral end products consisting only or predominantly of 17-oxoandrostanes derived from the corresponding urinary pregnane-17,21-diol-20-ones. The mixture of end products was resolved by gas-liquid or paper chromatography. The latter technique was used to determine cortisol secretion rates and the results were found to be in reasonable agreement with those obtained by a double-isotope method. Gas-liquid-chromatographic characterization of steroidal 4-en-3-ones is described.