Uric acid degrading enzymes, urate oxidase and allantoinase, are associated with different subcellular organelles in frog liver and kidney

Feasibility of using a novel algal-bacterial biofilm reactor for efficient domestic wastewater treatment

Current algal-bacterial consortia require high hydraulic retention times (HRTs, 2-10 days) to efficiently remove pollutants from domestic wastewaters. A novel algal-bacterial biofilm reactor was developed for a much lower HRT. The results showed that an HRT of 12 h ensured 90% removal of organic matter and ammonium, and phosphate removal was approximately 30%. Decreasing the HRT to 8 h significantly deteriorated the reactor's pollutant removal efficiencies and increasing the HRT to 24 h did not improve these efficiencies. Illumination, which was light source for algae, was provided by a LED light. Activity tests showed that organic matter and ammonium removal rates resulting from illumination were 70% and 50%, respectively, of the rates when dissolved oxygen concentration was maintained at 2 mg/L. Chemical oxygen demand (COD) removal rates resulted from illumination and aeration were 18.63 and 25.38 mg COD/L.h, respectively. The phosphate removal rate was 0.26 and 0.43 mg/L.h when illumination and aeration were applied, respectively. The ammonium removal rates were approximately 10,390 and 5000 mg [Formula: see text] when the reactor was aerated or illuminated, respectively. These two rates were significantly higher than reported nitrification rates. Moreover, the percentage of Oscillatoria sp. increased from below 10% to over 90% under the applied organic load and temperature, while the percentage of fast growing algae, Chlorella, chroococcus sp and Scenedesmus sp., decreased from over 90% to below 10%. These results showed that an algal-bacterial biofilm reactor with a low reactor footprint was developed.

Temporal Effects on Radiation Responses in Nonhuman Primates: Identification of Biofluid Small Molecule Signatures by Gas Chromatography⁻Mass Spectrometry Metabolomics

Whole body exposure to ionizing radiation damages tissues leading to physical symptoms which contribute to acute radiation syndrome. Radiation biodosimetry aims to determine characteristic early biomarkers indicative of radiation exposure and is necessary for effective triage after an unanticipated radiological incident. Radiation metabolomics can address this aim by assessing metabolic perturbations following exposure. Gas chromatography-mass spectrometry (GC-MS) is a standardized platform ideal for compound identification. We performed GC time-of-flight MS for the global profiling of nonhuman primate urine and serum samples up to 60 d after a single 4 Gy γ-ray total body exposure. Multivariate statistical analysis showed higher group separation in urine vs. serum. We identified biofluid markers involved in amino acid, lipid, purine, and serotonin metabolism, some of which may indicate host microbiome dysbiosis. Sex differences were observed for amino acid fold changes in serum samples. Additionally, we explored mitochondrial dysfunction by tricarboxylic acid intermediate analysis in the first week with a GC tandem quadrupole MS platform. By adding this temporal component to our previous work exploring dose effects at 7 d, we observed the highest fold changes occurring at 3 d, returning closer to basal levels by 7 d. These results emphasize the utility of both MS-based metabolomics for biodosimetry and complementary analytical platforms for increased metabolome coverage.

Nephromyces Encodes a Urate Metabolism Pathway and Predicted Peroxisomes, Demonstrating That These Are Not Ancient Losses of Apicomplexans

The phylum Apicomplexa is a quintessentially parasitic lineage, whose members infect a broad range of animals. One exception to this may be the apicomplexan genus Nephromyces, which has been described as having a mutualistic relationship with its host. Here we analyze transcriptome data from Nephromyces and its parasitic sister taxon, Cardiosporidium, revealing an ancestral purine degradation pathway thought to have been lost early in apicomplexan evolution. The predicted localization of many of the purine degradation enzymes to peroxisomes, and the in silico identification of a full set of peroxisome proteins, indicates that loss of both features in other apicomplexans occurred multiple times. The degradation of purines is thought to play a key role in the unusual relationship between Nephromyces and its host. Transcriptome data confirm previous biochemical results of a functional pathway for the utilization of uric acid as a primary nitrogen source for this unusual apicomplexan.

Characterization of purine catabolic pathway genes in coelacanths

Coelacanths are a critically valuable species to explore the gene changes that took place in the transition from aquatic to terrestrial life. One interesting and biologically relevant feature of the genus Latimeria is ureotelism. However not all urea is excreted from the body; in fact high concentrations are retained in plasma and seem to be involved in osmoregulation. The purine catabolic pathway, which leads to urea production in Latimeria, has progressively lost some steps, reflecting an enzyme loss during diversification of terrestrial species. We report the results of analyses of the liver and testis transcriptomes of the Indonesian coelacanth Latimeria menadoensis and of the genome of Latimeria chalumnae, which has recently been fully sequenced in the framework of the coelacanth genome project. We describe five genes, uricase, 5-hydroxyisourate hydrolase, parahox neighbor B, allantoinase, and allantoicase, each coding for one of the five enzymes involved in urate degradation to urea, and report the identification of a putative second form of 5-hydroxyisourate hydrolase that is characteristic of the genus Latimeria. The present data also highlight the activity of the complete purine pathway in the coelacanth liver and suggest its involvement in the maintenance of high plasma urea concentrations.

Be different--the diversity of peroxisomes in the animal kingdom

Peroxisomes represent so-called "multipurpose organelles" as they contribute to various anabolic as well as catabolic pathways. Thus, with respect to the physiological specialization of an individual organ or animal species, peroxisomes exhibit a functional diversity, which is documented by significant variations in their proteome. These differences are usually regarded as an adaptational response to the nutritional and environmental life conditions of a specific organism. Thus, human peroxisomes can be regarded as an in part physiologically unique organellar entity fulfilling metabolic functions that differ from our animal model systems. In line with this, a profound understanding on how peroxisomes acquired functional heterogeneity in terms of an evolutionary and mechanistic background is required. This review summarizes our current knowledge on the heterogeneity of peroxisomal physiology, providing insights into the genetic and cell biological mechanisms, which lead to the differential localization or expression of peroxisomal proteins and further gives an overview on peroxisomal biochemical pathways, which are specialized in different animal species and organs. Moreover, it addresses the impact of proteome studies on our understanding of differential peroxisome function describing the utility of mass spectrometry and computer-assisted algorithms to identify peroxisomal target sequences for the detection of new organ- or species-specific peroxisomal proteins.

X-ray microanalysis of biological specimens by high voltage electron microscopy

For the purpose of analyzing and imaging chemical components of cells and tissues at the electron microscopic level, 3 fundamental methods are available, chemical, physical and biological. Among the physical methods, two methods qualifying and quantifying the elements in the structural components are very often employed. The first method is radioautography which can demonstrate the localization of radiolabeled compounds which were incorporated into cells and tissues after the administration of radiolabeled compounds. The second method is X-ray microanalysis which can qualitatively analyze and quantify the total amounts of elements present in cells and tissues. We have developed the two methodologies in combination with intermediate high or high voltage transmission electron microscopy (200-400 kV) and applied them to various kinds of organic and inorganic compounds present in biological materials. As for the first method, radioautography, I had already contributed a chapter to PHC (37/2). To the contrary, this review deals with another method, X-ray microanalysis, using semi-thin sections and intermediate high voltage electron microscopy developed in our laboratory. X-ray microanalysis is a useful method to qualify and quantify basic elements in biological specimens. We first quantified the end-products of histochemical reactions such as Ag in radioautographs, Ce in phosphatase reaction and Au in colloidal gold immunostaining using semithin sections and quantified the reaction products observing by intermediate high voltage transmission electron microscopy at accelerating voltages from 100 to 400 kV. The P/B ratios of all the end products Ag, Ce and Au increased with the increase of the accelerating voltages from 100 to 400 kV. Then we analyzed various trace elements such as Zn, Ca, S and Cl which originally existed in cytoplasmic matrix or cell organelles of various cells, or such elements as Al which was absorbed into cells and tissues after oral administration, using both conventional chemical fixation and cryo-fixation followed by cryo-sectioning and freeze-drying, or freeze-substitution and dry-sectioning, or freeze-drying and dry-sectioning producing semithin sections similarly to radioautography. As the results, some trace elements which originally existed in cytoplasmic matrix or cell organelles of various cells in different organs such as Zn, Ca, S and Cl, were effectively detected. Zn was demonstrated in Paneth cell granules of mouse intestines and its P/B ratios showed a peak at 300 kV. Ca was found in human ligaments and rat mast cells with a maximum of P/B ratios at 350 kV. S and Cl were detected in mouse colonic goblet cells with maxima of P/B ratios at 300 kV. On the other hand, some elements which were absorbed by experimental administration into various cells and tissues in various organs, such as Al in lysosomes of hepatocytes and uriniferous tubule cells in mice was detected with a maximum of P/B ratios at 300 kV. From the results, it was shown that X-ray microanalysis using semi-thin sections observed by intermediate high voltage transmission electron microscopy at 300-400 kV was very useful resulting in high P/B ratios for quantifying some trace elements in biological specimens. These methodologies should be utilized in microanalysis of various compounds and elements in various cells and tissues in various organs.

Insect allantoinase: cDNA cloning, purification, and characterization of the native protein from the cat flea, Ctenocephalides felis

Allantoinase catalyses the hydrolysis of allantoin to allantoic acid. This reaction is a step in the purine degradation pathway, which produces nitrogenous waste for excretion. A cDNA encoding full-length allantoinase was cloned from a Ctenocephalides felis hindgut and Malpighian tubule (HMT) cDNA library. The cDNA encoded a 483 amino acid protein that had 43% identity with the bullfrog Rana catesbeiana allantoinase and contained the conserved histidine and aspartic acid residues required for zinc-binding and catalytic activity. Unlike the bullfrog allantoinase, the C. felis allantoinase sequence was predicted to contain a 22 amino acid signal sequence, which targets the protein to the secretory pathway. Expression of the mRNA was detected by Northern blot in the first, third, and wandering larval stages as well as in fed and unfed adults, but was not seen in eggs or pupae. In adults, mRNA encoding allantoinase was detected only in the HMT tissues. Immunohistochemistry performed using affinity-purified rabbit immune serum generated against purified recombinant flea allantoinase showed that the native protein localized to the HMT tissues in adult fleas. The anti-allantoinase serum recognized two proteins in an adult flea soluble protein extract, one migrating at 56 kDa and the other at 53 kDa. The two proteins were separated by gel filtration chromatography and were both associated with allantoinase activity. The difference in size appeared to be due to a difference in glycosylation of the proteins. The 53 kDa protein was further purified to near homogeneity by affinity chromatography and retained allantoinase activity. A comparison of the sizes of the native and recombinant C. felis proteins indicated that the 53 kDa native protein may be the product of a post-translational cleavage event, possibly at the putative 22 amino acid signal sequence at the N-terminus of the protein.

Special cytochemistry in cell biology

Cytochemistry is a science of localizing chemical components of cells and organelles on histological sections by using various techniques. We first aimed at studying cytochemistry by developing new techniques using various principles such as enzyme cytochemistry, microincineration, microspectrophotometry, radioautography, cryo-techniques, X-ray microanalysis and immunocytochemistry. We first concentrated on developing methodologies in the 1960s to 1970s. We then applied these special techniques to various kinds of cells in men and animals. Earlier, I proposed to classify these methods into three categories, i.e., chemical, physical, and biological techniques. The methodology has been well developed to form a new science which should be designated as "general cytochemistry" similarly to the general histology. On the other hand, these techniques should be applied to various cells in various organ systems, such as the skeletal, muscular, digestive, respiratory, urinary, reproductive, endocrine, circulatory, nervous and sensory systems similarly to the special histology or the histology of organs. I summarize the results of cytochemical studies on cells of various organs carried out in our laboratory during these 44 years since 1955. The results obtained from cytochemical studies applied to various cells in respective organ systems should be designated as "special cytochemistry."

Xenopus allantoicase: molecular cloning, enzymatic activity and developmental expression

Allantoicase is one of the enzymes of the purine degradation pathway and, interestingly, it appears to be lost, together with uricase and allantoinase, during mammalian evolution. Only allantoicases from the ascomycetes S. pombe, S. cerevisiae, and N. crassa have already been cloned, although the activity has been reported also in fishes and amphibians. By screening a cDNA expression library of Xenopus liver, we have cloned a 1491-bp-length cDNA coding for a 389 amino acid protein that shows an high similarity with the enzyme allantoicase. We have found that allantoicase mRNA is abundantly expressed in kidney and liver, but at much lower level is also present in brain, testis, intestine, and lung. We have detected enzymatic activity in crude extract from kidney, liver, and lung; we have also determined kinetic parameters (K(m) = 8.44 mM, V(max) = 6. 94 micromol min(-1) per mg protein) in kidney. During embryo development, we have detected allantoicase transcript and activity starting from 1 and 5 days after fertilization, respectively.

Immunohistochemical localization of peroxisomal enzymes in developing rat kidney tissues

We studied the developmental changes in the localization of peroxisome-specific enzymes in rat kidney tissues from embryonic Day 16 to postnatal Week 10 by immunoblot analysis and immunohistochemistry, using antibodies for the peroxisomal enzymes catalase, d-amino acid oxidase, l-alpha-hydroxyacid oxidase (isozyme B), and enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase bifunctional protein. Peroxisomal enzymes were detected in the neonatal kidney by immunoblot analysis and their amount increased with kidney development. By light microscopic immunohistochemistry, they were first localized in a few proximal tubules in the juxtamedullary cortex of 18-day embryos. The distribution of proximal tubules positive for them expanded towards the superficial cortex with development. The full thickness of the cortex became positive for the staining by 14 days after birth. Peroxisomes could be detected by electron microscopy in structurally immature proximal tubules in 18-day embryos. Their size increased and the ultrastructure of subcompartments became clear with continuing development of proximal tubules. These results show that peroxisomal enzymes appear in the immature proximal tubules in the kidney of embryos and that the ultrastructure of the peroxisomes and localization of the peroxisomal enzymes develop along with the maturation of proximal tubules and kidney tissues.

In situ heterogeneity of peroxisomal oxidase activities: an update

Oxidases are a widespread group of enzymes. They are present in numerous organisms and organs and in various tissues, cells, and subcellular compartments, such as mitochondria. An important source of oxidases, which is investigated and discussed in this study, are the (micro)peroxisomes. Oxidases share the ability to reduce molecular oxygen during oxidation of their substrate, yielding an oxidized product and hydrogen peroxide. Besides the hydrogen peroxide-catabolizing enzyme catalase, peroxisomes contain one or more hydrogen peroxide-generating oxidases, which participate in different metabolic pathways. During the last four decades, various methods have been developed and elaborated for the histochemical localization of the activities of these oxidases. These methods are based either on the reduction of soluble electron acceptors by oxidase activity or on the capture of hydrogen peroxide. Both methods yield a coloured and/or electron dense precipitate. The most reliable technique in peroxisomal oxidase histochemistry is the cerium salt capture method. This method is based on the direct capture of hydrogen peroxide by cerium ions to form a fine crystalline, insoluble, electron dense reaction product, cerium perhydroxide, which can be visualized for light microscopy with diaminobenzidine. With the use of this technique, it became clear that oxidase activities not only vary between different organisms, organs, and tissues, but that heterogeneity also exists between different cells and within cells, i.e. between individual peroxisomes. A literature review, and recent studies performed in our laboratory, show that peroxisomes are highly differentiated organelles with respect to the presence of active enzymes. This study gives an overview of the in situ distribution and heterogeneity of peroxisomal enzyme activities as detected by histochemical assays of the activities of catalase, and the peroxisomal oxidases D-amino acid oxidase, L-alpha-hydroxy acid oxidase, polyamine oxidase and uric acid oxidase.

On the significance of brain extracellular uric acid detected with in-vivo monitoring techniques: a review

The concentration of uric acid [UA] in the extracellular fluid (ECF) estimated with in-vivo voltammetry and microdialysis data is compared for probes of different diameters from the day of implantation (acute) to several days (chronic) or even months after surgery. For small probes (diameter < 160 microns) the acute [UA] of ca. 5 microM decreased significantly to ca. 1 microM under chronic conditions. For larger probes (e.g., 320-microns diameter) the acute [UA] was also ca. 5 microM, but this value significantly increased to ca. 50 microM under chronic conditions. Associated with this difference in [UA], there were parallel differences in the extent of gliosis around the probes. These findings are discussed in terms of possible sources of extracellular UA and their implications for in-vivo monitoring techniques in behaving animals.

Immunogold studies on peroxisomes: review of the localization of specific proteins in vertebrate peroxisomes

Peroxisomes, since their discovery as microbodies, have been studied mostly independently by electron microscopists and biochemists. The fine structure has been studied by electron microscopy, and the compositional enzymes and proteins by protein biochemistry. Electron microscopic histochemistry has been used to try to clarify the relationship between the fine structure and its constituents. The immunogold technique, a combination of electron microscopy and protein biochemistry, for the first time resolved this problem due to the high sensitivity and resolution power of the staining and the high reliability of the technique. The present paper reviews the way in which the immunogold techniques, especially the protein A-gold technique, revealed the localization of various enzymes or proteins in peroxisomes or peroxisomal subcompartments, and discusses why this technique should be employed in peroxisome research.