Screening of poly-β-hydroxybutyrate-producing microorganisms using Fourier transform infrared spectroscopy

An alternative method for the analysis of poly--hydroxybutyrate (PHB) in microbial biomass based on FTIR spectroscopy was developed in which a semi-transparent, thin pellet of biomass was made with KBr and scanned by IR spectroscopy, from 400 cm^–1to 2000 cm^–1. The IR spectra of the target biomass showed a distinct absorbance band of the carboxylic ester group at 1724.03 cm^–1. The technique can be used to screen large numbers of microorganisms for PHB production.     

Effects of Lovastatin and Pravastatin on Amyloid Processing and Inflammatory Response in TgCRND8 Brain

Previous studies suggest that treatment with statins reduce beta amyloid (Abeta) deposition in brains of mouse models of Alzheimer's disease (AD) and may reduce the prevalence of AD in humans. Since lipophilicity influences the biological efficacy of statins, we compared the effects of lovastatin, a lipophilic statin, to effects of the hydrophilic pravastatin on amyloid processing and inflammatory responses in brain. Three-month old TgCRND8 mice expressing mutant human amyloid precursor protein (mHuAPP) were treated daily with various doses of either statin. After 1 month, levels of cerebral soluble and fibrillar Abeta peptides, soluble sAPPalpha, and inflammatory cytokines were measured. Both statins caused dose-dependent reductions in total Abeta peptides with parallel increases in total sAPPalpha. At all doses, slightly greater effects were observed with lovastatin than with pravastatin. In contrast, only lovastatin significantly increased levels of IL-1beta and of TNFalpha in a dose-dependent manner. Lovastatin, but not pravastatin, decreased succinic dehydrogenase and increased lactate dehydrogenase activities in skeletal muscle and increased TUNEL staining in liver. Our data demonstrate that both statins shift the balance of APP processing from excessive beta-toward the normal alpha-cleavage while reducing the total amyloid burden in TgCRND8 brain and that lovastatin, but not pravastatin, potentiates cerebral inflammation and is associated with liver and muscle histotoxicity in these animals. These data show that pravastatin can reduce amyloid burden without potentiating inflammatory responses in brain and, therefore, may have a wider dose-range of safety than have lipophilic statins in the treatment or prevention of AD.     

Analysis of Erythrocyte and Platelet Membrane Proteins in Various Forms of β-Thalassemia

Major membrane proteins have been quantitatively analyzed in erythrocytes and platelets from patients with homozygous (splenectomized and non-splenectomized) and heterozygous forms of beta-thalassemia depending on severity of clinical manifestation of this disease. Quantitative analysis of erythrocyte membrane proteins revealed increase in alpha- and beta-spectrin. (In non-splenectomized patients with homozygous beta-thalassemia the amount of this protein was lower than in corresponding controls.) Besides spectrin, the increase of 2.1-2.3 fractions of ankyrin, and the decrease of band 3 protein (anion-transport protein), 4.1, palladin, and glyceraldehyde-3-phosphate dehydrogenase were also found. Analysis of major platelet membrane proteins revealed significant increase in gelsolin. This increase was found in all forms of beta-thalassemia irrespective of gender. Significant changes in platelet membrane protein fractions were found in patients (especially non-splenectomized) with homozygous beta-thalassemia. These included significant decrease in myosin, profilin, and gamma-actin and increase in actin-binding protein in both male and female patients. The content of other protein fractions (alpha-actinin, tubulin, tropomyosin) remained unchanged. Changes in protein fractions of erythrocytes and platelets correlated with severity of clinical manifestation of the disease.     

The air-blood barrier in the human lung

Summary The air-blood barrier was studied in replicas of freeze-fractured lung biopsies collected from healthy human subjects. Adjacent pneumocytes display a belt-like network composed of 3–7 superimposed ridges (fibrils) on the P face and complementary grooves on the E face, i.e., a structure corresponding to a tight junction. On the other hand, adjacent capillary endothelial cells show a continuous system of 2–4 membrane foldings. These appear mainly as smooth surfaced crests on the P face; on the E face furrows are seen, at the bottom of which a row of particles is situated. This arrangement suggests a leaky type of junction. Discontinuous occluding junctions are located in the pericytic venular segment of the alveolar vessels. The present findings are in agreement with previous physiological and ultrastructural tracer studies locating the main part of the diffusion barrier for small polar solutes and proteins in the alveolar epithelium. Communicating junctions are demonstrated between type I and type II pneumocytes, indicating intercellular cooperation between these cells of common embryonic origin, but which fulfill different functions in the adult. In the endothelium of the non-muscular alveolar vessels communicating junctions are lacking. Desmosomes occur in the epithelium between type I and type II pneumocytes; square arrays of particles characterize the plasma membrane of type I pneumocytes.A portion of this work was presented in partial fulfillment for the degree of Dr. med., Hannover Medical School     

Induction of cellulose- and xylan-degrading enzyme complex in the yeast Trichosporon cutaneum

The specificity of induction of cellulose- and xylan-degrading enzymes was investigated on the yeast strain Trichosporon cutaneum CCY 30-5-4 using series of compounds structurally related to cellulose and xylan, including monosaccharides, glycosides, glucooligosaccharides and xylooligosaccharides. Determination of activities of secreted cellulase and -xylanase, intracellular, cell wall bound and extracellular -glucosidase and -xylosidase revealed that: (1) The synthesis of xylan-degrading enzymes is induced in the cell only by xylosaccharides, 1,3--xylobiose, 1,2--xylobiose, 1,4--xylosyl-L-arabinose, 1,4--xylobiose and thioxylobiose being the best inducers. The xylan-degrading enzymes show different pattern of development in time and discrete cellular localization, i.e. intracellular -xylosidase precedes extracellular -xylanase. (2) A true cellulase is not inducible by glucosaccharides and cellulose. Negligible constitutive cellulase activity was detected which was about two orders lower than an induced cellulase in the typical cellulolytic fungus Trichoderma reesei QM 9414. (3) The best inducer of intracellular -glucosidase splitting cellobiose was thiocellobiose in a wide range of concentration (0.1–10 mM), whereas xylosaccharides at high concentrations induced -xylosidase of xylobiose type and a non-specific aryl -D-glucosidase.The results were confirmed by growing cells on cellulose and xylan. T. cutaneum was found to be a xylan-voracious yeast, unable to grow on cellulose.     

Effect of hyperprolinemia on acetylcholinesterase and butyrylcholinesterase activities in rat

Summary. We observed here that acute proline (Pro) administration provoked a decrease (32%) of acetylcholinesterase (AChE) activity in cerebral cortex and an increase (22%) of butyrylcholinesterase (BuChE) activity in the serum of 29-day-old rats. In contrast, chronic administration of Pro did not alter AChE or BuChE activities. Furthermore, pretreatment of rats with vitamins E and C combined or alone, N-nitro-L-arginine methyl ester or melatonin prevented the reduction of AChE activity caused by acute Pro administration, suggesting the participation of oxidative stress in such effects.     

The role of macrophages in the tissues regeneration stimulated by the biomaterials

Allogenic grafted tissues are subjected to biodegradation and replaced by the regenerate. To minimize the immune response and improve the rebuilding of tissues there was developed a technology to treat tissues with a cells elimination and dosed out extraction of proteoglycanes (Alloplant^®). With aim to clarify the role of macrophages in the tissues regeneration resulting implantation the biomaterials 112 rats were injected the allogenic and xenogenic (rabbits) pulverized biomaterials in the form of suspension. Injections were performed subcutaneously into the animals back by the base of the tail. The control group (14 rats) were injected a physiologic saline. Animals were killed by ether inhalation on day 2, 4, 7, 14, 30, 90 and 180 and tissue sections were studied by light and electron microscopy. The study showed the key role of the macrophages in resorption of the allogenic biomaterial and formation of the newly-formed tissue. Implantation of the biomaterial induced activity a great number of the mature macrophages, which completely lysed and resorbed the biomaterial particles. Expression TNF was significantly higher whereas expression TGF-1 was significantly lower. With xenogenic biomaterial implantation there were less macrophages, their activity was restricted. Macrophages containing large vacuoles with an active endo- and exocytosis were revealed in the allogenic biomaterial implantation and were named matrix-forming macrophages. We may suppose that these macrophages synthesize (or re-synthesize) proteoglycan component of the newly-formed collagen fibers. There was put forward a hypothesis about the two component mechanism of the collagen fibers formation.     

The use of norbornene derivatives in the synthesis of conformationally constrained peptides and pseudo-peptides

The desymmetrisation of endo-norborn-5-ene-2,3-dicarboxylic anhydride by proline esters has been used to prepare conformationally constrained pseudo-peptides with two peptide chains parallel to one another. A Curtius rearrangement on the desymmetrisation adduct produced the corresponding isocyanate which was used to prepare both a peptide incorporating an endo-2-amino-3-carboxy-norborn-5-ene unit, and a pseudo-peptide with two peptide chains parallel to one another but offset by the presence of a urea unit. The conformational analysis of the resulting peptides was carried out, and the norbornene unit was found to induce the formation of -turns and parallel -sheets.     

The rapid switch-off of nitrogenase activity in obligate methane-oxidizing bacteria

Nitrogenase activity in the obligate methaneoxidizing bacterium Methylococcus capsulatus (Bath) was added ammonia. This observation was extended to include other ammonia. This observation was extended to include other representative N₂-fixing species of methanotrophs. The ammonia switch-off of nitrogenase in M. capsulatus (Bath) was reversed on washing cells to remove excess ammonia, in the presence of chloramphenicol, suggesting that a form of covalent modification of nitrogenase may occur. Replacing the oxidizable substrate methanol with formaldehyde, formate, ethanol or hydrogen had no effect on nitrogenase switch-off. A number of potential nitrogen sources or intermediates of nitrogen metabolism such as glutamine, asparagine, glutamate and alanine when tested, did not effect switch-off. However, the rapid inhibition of nitrogenase activity of M. capsulatus (Bath) could be achieved by adding the uncoupler carbonylcyanide m-chlorophenylhydrazone or nitrite. The glutamine synthetase inhibitor methionine sulphoximine blocked the switch-off effect of ammonia, indicating that the metabolism of ammonia may be essential for switch-off to occur. Inhibitors of glutamate synthase did not alleviate the ammonia switch-off response. Methionine sulphoximine did not alleviate the rapid inhibition of nitrogenase by carbonylcyanide m-chlorophenylhydrazone indicating that the shortterm regulation of nitrogenase by uncouplers and ammonia proceed via different mechanisms.Abbreviations MSX methionine-DL-sulphoximine - DON 6-diazo-5-oxo-L-norleucine - GS glutamine synthetase - GOGAT glutamine 2-oxoglutarate aminotransferase (glutamate synthase) - CCCP carbonylcyanide m-chlorophenyl hydrazone     

Different evolution rates within the lens-specificβ-crystallin gene family

Summary We have determined the sequence of a rat A3/A1-crystallin complementary DNA (cDNA) clone and the (partial) sequence of the human B3-crystallin gene. Calculation of the ratio of silent to nonsynonymous substitution between orthologous A3/A1-, B3-, and other - and -crystallin sequences revealed that the region encoding the two globular domains of the A3/A1-crystallin sequence is the best conserved during evolution, much better than the corresponding region of the B1-, B3-, or the -crystallin sequences, and even better (at least in the rodent/frog comparison) that the well-conserved A-crystallin sequence. Remarkably, the rate of change of the A3/A1-crystallin coding sequence does not differ in the rodent and primate lineages, in contrast with previous findings concerning the evolution rates of the A- or -crystallin sequences in these two lineages. Comparison of the regions that encode the four motifs of the -crystallin between orthologous mammalian sequences showed that the extent of nonsynonymous substitution in each of these four homologous motif regions is the same. However, when the orthologous -crystallin genes of more distantly related species (mammals vs chicken or frog) are compared, the extent of nonsynonymous substitution is higher in the regions encoding the external motifs I and III than in the regions encoding the internal motifs II and IV. This phenomenon is also observed when paralogous members of the /-crystallin supergene family are compared.     

Carrot (Daucus carota) hypocotyl transformation usingAgrobacterium tumefaciens

Summary Daucus carota hypocotyl sections were transformed withAgrobacterium tumefaciens LBA4404 containing CaMV 35S promoter, -glucuronidase coding sequence and the nopaline synthase (Nos) poly adenylation sequences in Bin 19. Sliced sterile seedling hypocotyl segments were preincubated for 2 days, co-cultivated withAgrobacterium for an additional 2 days, and then transferred to medium containing 100ug/ml of kanamycin and 400ug/ml carbenicillin. In 6 weeks kanamycin resistant calli were obtained in 5.8% of the explants from one variety. Calli were subcultured on solid medium, and in 4 weeks introduced into suspension culture. NPTII and Southern blot analysis confirmed that three selected lines were transformed with 1–3 copies of the GUSII construction. GUS activity in transformants was 5 to 250 fold over background.Abbreviations NPT II neomycin phosphotransferase II - Nos nopaline synthase - GUS -glucuronidase - CaMV cauliflower mosaic virus - 2,4-D 2,4 dichlorophenoxyacetic acid - PMSF phenylmethylsulfonyl fluoride     

Ilyobacter delafieldii sp. nov., a metabolically restricted anaerobic bacterium fermenting PHB

Enrichments from an estuarine sediment with crotonate as substrate resulted in the isolation of a motile, gram-negative, obligately anaerobic rod with pointed ends, designated strain 10cr1. The organism was asporogenous, did not reduce sulfur, sulfate, thiosulfate, nitrate, oxygen or fumarate, and had a mol %G+C ratio of 29. Strain 10cr1 was able to ferment crotonate, 3-hydroxybutyrate, lactate, pyruvate, and poly--hydroxybutyric acid (PHB). Acetate, propionate, butyrate, CO₂ and H₂ were the fermentation products. When grown on PHB there was accumulation of 3-hydroxybutyrate once growth had ceased, indicating degradation of PHB to the monomer. The 3-hydroxybutyrate formed during growth of the culture was fermented to acetate, butyrate and H₂. Experimental evidence suggested the production of an extracellular PHB depolymerase. The cells were not attached to the PHB granules. This is the first isolation of an anaerobic bacterium capable of degrading exogenous PHB. This strain is described as a new species, Ilyobacter delafieldii sp. nov., and strain 10cr1 (=DSM 5704) is designated as the type (and at present, only) strain.Abbreviations G+C guanine plus cytosine - OD optical density - PHB poly--hydroxybutyric acid - specific growth rate - HPLC high-performance liquid chromatography - YE yeast extract     

cDNA cloning and expression of a potato (Solanum tuberosum) invertase

A cDNA clone encoding an invertase isoenzyme has been isolated from a potato leaf cDNA library. The deduced amino acid sequence shows significant similarities to previously characterised invertases. The highest degree of overall similarity, including the signal peptide sequence, is to carrot cell wall invertase, suggesting that the potato gene encodes an apoplastic enzyme. Expression of the gene, as determined by RT-PCR, is detected in stem and leaf tissue, and at lower levels in tuber, but is absent from roots.     

β-Adrenergic receptor activity of cerebral microvessels is reduced in aged rats

The effect of age on beta-() adrenergic receptor number (B_max) and adenylate cyclase (AC) activity was determined in microvessels isolated from male F-344 rats at 3, 18, and 24 months of age. Scatchard analysis of [¹²⁵I]iodocyanopindolol (ICYP) binding indicated reduced Bmax (fmol/mg) of microvessels isolated from 24 month old rats (27.2±4.9) compared with 3 month old (50.4±5.2) and 18 month old rats (p<0.01) (61.4±7.6). The basal AC activity (pmol cAMP/mg) in 24 month old rats (32.0 ±6.7) and in 18 month old rats (30.4±2.1) were significantly reduced compared to the basal activity in the young (50.1±4.2). The net isoproterenol or NaF stimulated AC activity in 24 month old rats (zero and 15.6±8.5 respectively) was also reduced compared to young rats (10.1±3.9 and 166.0±21.2 respectively). It is concluded that aging is associated with reduced isoproterenol stimulated AC activity of cerebral microvessels. This reduction is the product of reduced -adrenergic receptor number and reduced activity of AC in aged rat cerebral microvessels.     

Correlation of the number of pineal “synaptic” ribbons and spherules with the level of serum melatonin over a 24-hour period in male rabbits

Summary Previous studies have shown that pineal synaptic ribbons and spherules may respond differently under normal and experimental conditions. It has been suggested that the increase in the number of ribbons may be a prerequisite for enhanced melatonin formation. In the present study, the number of ribbons and spherules as well as the level of serum melatonin were monitored over a 24-h period in the male rabbit, the pineal gland of which is known to contain many spherules. It was found that both the number of ribbons and the levels of serum melatonin show the typical nocturnal increase, exhibiting peaks at 02:00 and 06:00 h, respectively. There is a good correlation (R = 0.8) of the two parameters. The spherules, in contrast, show no statistically significant circadian changes in number and cannot be correlated with the levels of serum melatonin. It is concluded that ribbons and spherules may differ in function and that the ribbons may be somehow involved in the regulation of melatonin formation.Supported by the Deutsche Forschungsgemeinschaft (Grant Vo 135/7) within the project SPP Neuroendokrinologie     

Biochemical and genetic factors in the heat inactivation of murine β-glucuronidase

The enzymes coded for by two alleles at the glucuronidase structural locus (Gus) were compared in their response to pH, buffering anion, buffer molarity, ionic strength, and temperature. The heat-labile Gus^h gene product responded in a qualitatively similar but quantitatively reduced manner compared to the relatively heat-stable Gus ^b gene product. In all buffers tested, the enzyme was most heat stable at pH 5.0. Ranking of the various buffer anions tested, according to increasing heat stabilization, was water acetate phosphate < citrate. Varying the molarity of the buffers from 0.01 to 0.6 m at pH 5.0 revealed further differences among the buffers. Increasing ionic strength exerted a destabilizing force on the protein. The half-life of the enzyme decreased by as much as a hundredfold between 71 and 75 C. The Gus^h/Gus^h genotype also results in decreased activity levels in all tissues, reportedly because of decreased synthesis. The heat inactivation curves of Gus^b/Gus^h heterozygotes were incompatible with any theoretical curve based on the assumption that the Gus^b and Gus^h chromosomes in the heterozygote behave in a manner similar to that seen in the homozygotes.This research was supported by a Basil O'Connor Starter Research Grant from the National Foundation—March of Dimes (R. J. M.) and by a grant from The Jane Coffin Childs Memorial Fund for Medical Research (K. H.).Fellow of The Jane Coffin Childs Memorial Fund for Medical Research.     

Association of the 5′ HS4 sequence of the chicken β‐globin locus control region with human EF1α gene promoter induces ubiquitous and high expression of human CD55 and CD59 cDNAs in transgenic rabbits

Whatever its field of application, animal transgenesis aims at a high level of reproducible and stable transgene expression. In the case of xenotransplantation, prevention of hyperacute rejection of grafts of animal origin requires the use of organs expressing human inhibitors of complement activation such as CD55 (DAF) and CD59. Pigs transgenic for these molecules have been produced, but with low and variable levels of expression. In order to improve cDNA expression, a vector containing the 5HS4 region from the LCR of the chicken globin locus and the promoter and the first intron from the human EF1 gene, was used to coexpress human CD55 and CD59 cDNAs in transgenic rabbits. The transgenic lines with the 5HS4 region displayed dramatically enhanced CD55 and CD59 mRNA concentrations in brain, heart, kidney, liver, lung, muscle, spleen and aortic endothelial cells in comparison with the transgenic lines without the 5HS4 region. In the absence of the 5HS4 region, only some of the transgenic lines displayed specific mRNAs and at low levels. Human CD55 and CD59 proteins were detectable in mononuclear cells from transgenic rabbits although at a lower level than in human mononuclear cells. On the other hand, primary aortic endothelial cells from a bitransgenic line were very efficiently protected in vitro against human complementdependent lysis. Transgenic rabbits harbouring the two human inhibitors of complement activation, CD55 and CD59, can therefore be used as new models in xenotransplantation. Moreover, the vector containing the 5HS4 region from the LCR of the chicken globin locus seems appropriate not only for xenotransplantation but also for any other studies involving transgenic animals in which cDNAs have to be expressed at a high level in all cell types.     

Short Communication: Purification and characterization of an intracellular β-glucosidase from Cellulomonas biazotea

World Journal of Microbiology and Biotechnology -     

Purification and characterization of β‐methylaspartase from Fusobacterium varium

Methylaspartase (EC 4.3.1.2) was purified 20fold in 35% yield from Fusobacterium varium, an obligate anaerobe. The purification steps included heat treatment, fractional precipitation with ammonium sulfate and ethanol, gel filtration, and ion exchange chromatography on DEAESepharose. The enzyme is dimeric, consisting of two identical 46 kDa subunits, and requires Mg²⁺ (K_m = 0.27 ± 0.01 mM) and K⁺ (K_m = 3.3 ± 0.8 mM) for maximum activity. Methylaspartasecatalyzed addition of ammonia to mesaconate yielded two diastereomeric amino acids, identified by HPLC as (2S,3S)3methylaspartate (major product) and (2S,3R)3methylaspartate (minor product). Optimal activity for the deamination of (2S,3S)3methylaspartate (K_m = 0.51 ± 0.04 mM) was observed at pH 9.7. The Nterminal protein sequence (30 residues) of the F. varium enzyme is 83% identical to the corresponding sequence of the clostridial enzyme.