Hyperproduction of L-glutamate oxidase in submerged fermentation of Streptomyces sp. N1 with culture pH control and calcium addition

Production of L-glutamate oxidase (GluOx) by Streptomyces sp. N1 was investigated by controlling culture pH at 6.2, 6.7, 7.0, and 7.3 in a 5-L stirred fermentor. The corresponding GluOx activities obtained were 2.8, 4.2, 6.0, and 5.3 U/mL, respectively. Microbial growth was inhibited by increasing the medium pH from 6.2 to 7.0. The inhibitory effect was also observed in plate colony growth under incubation with a different initial pH value. The effect of calcium on GluOx production was also studied in the pH-controlled bioreactor. When the culture pH was controlled at 6.2 or 7.0, GluOx production could not be improved or was only improved slightly by initial addition of calcium to the medium. However, when the culture pH was kept at 6.7, initial Ca2+ addition (60 mM) conspicuously enhanced GluOx production up to 9.3 U/mL, which was about twofold of that without Ca2+ addition. The enzyme production level was the highest ever reported in the literature. During fermentation the inhibition of cell growth by Ca2+ addition was observed. For the morphological changes, the cells mostly existed as pellets in the medium without Ca2+ addition, whereas few pellets were found and almost all the cells were dispersed mycelia in the broth with Ca2+ addition.

Coulomb sink: a novel coulomb effect on coarsening of metal nanoclusters on semiconductor surfaces

We propose the concept of a "Coulomb sink" to elucidate the effect of Coulomb charging on coarsening of metal mesas grown on semiconductor surfaces. We show that a charged mesa, due to its reduced chemical potential, acts as a Coulomb sink and grows at the expense of neighboring neutral mesas. The theory explains qualitatively the most salient features of coarsening of charged Pb mesas on the Si(111) surface, as observed by a scanning tunneling microscope. It provides a potentially useful method for controlled fabrication of metal nanostructures.

Nitrogen export from an agriculture watershed in the Taihu Lake area, China

Temporal changes in nitrogen concentrations and stream discharge, as well as sediment and nitrogen losses from erosion plots with different land uses, were studied in an agricultural watershed in the Taihu Lake area in eastern China. The highest overland runoff loads and nitrogen losses were measured under the upland at a convergent footslope. Much higher runoff, sediment and nitrogen losses were observed under upland cropping and vegetable fields than that under chestnut orchard and bamboo forest. Sediment associated nitrogen losses accounted for 8-43.5% of total nitrogen export via overland runoff. N lost in dissolved inorganic nitrogen forms (NO(3-)-N + NH4+-N) accounted for less than 50% of total water associated nitrogen export. Agricultural practices and weather-driven fluctuation in discharge were main reasons for the temporal variations in nutrient losses via stream discharge. Significant correlation between the total nitrogen concentration and stream discharge load was observed. Simple regression models could give satisfactory results for prediction of the total nitrogen concentrations in stream water and can be used for better quantifying nitrogen losses from arable land. Nitrogen losses from the studied watershed via stream discharge during rice season in the year 2002 were estimated to be 10.5 kg N/ha using these simple models.

Determination of the solubility of inorganic salts by headspace gas chromatography

This work reports a novel method for determination of salt solubility using headspace gas chromatography. A very small amount of volatile compound (such as methanol) is added in the studied solution. Due to the molecular interaction in the solution, the vapor-liquid equilibrium (VLE) partitioning coefficient of the volatile species will change with different salt contents in the solution. Therefore, the concentration of volatile species in the vapor phase is proportional to the salt concentration in the liquid phase, which can be easily determined by headspace gas chromatography. Until the salt concentration in the solution is saturated, the concentration of volatile compound in the vapor phase will continue to increase further and a breakpoint will appear on the VLE curve. The solubility of the salts can be determined by the identification of the breakpoint. It was found that the measured solubility of sodium carbonate and sodium sulfate in aqueous solutions is slightly higher (about 6-7%) than those reported in the literature method. The present method can be easily applied to industrial solution systems.

Quantification and reduction of organic sulfur compound formation in a commercial wood pulping process

This study experimentally quantified the formation of organic sulfur compounds in a commercial SuperBatch kraft pulping process using a laboratory pilot-scale digester. The results indicate that wood chips not only can adsorb HS- but also methyl mercaptan (MM) in the black liquor used for pretreatment during the two pretreatment stages. The absorption rate of MM is much faster than that of HS-. In the third stage of SuperBatch pulping, the rate of formation of MM and dimethyl sulfide (DMS) is very similar to that found in conventional batch kraft pulping processes. The study examined the applicability of the phase transition cooking (PTC) concept for reducing organic sulfur compounds in pulping, previously developed in laboratory batch pulping using a bomb-type digester, in a SuperBatch process. It was confirmed that there is a phase transition point (PTP) corresponding to PTC in SuperBatch pulping beyond which further delignification significantly increases the formation of volatile organic sulfur compounds. The results indicate that a 40% reduction of TRS formation can be achieved by using PTC.

Multiple headspace extraction-gas chromatographic method for the study of process kinetics

A multiple headspace extraction gas chromatographic technique to automate the study of process kinetics that involves volatile species was developed in this study. The technique was demonstrated by using it to study methanol formation in kraft black liquor samples under an isothermal temperature of 70 degrees C. The results indicate that methanol formation in kraft black liquors under isothermal conditions follows an exponential decay function. The present method is very simple, efficient and fully automated. It can be easily applied to study slow kinetic processes, such as reaction or adsorption and desorption, involving volatile species in any environmental and industrial samples with complicated matrices.

Cutting edge: predominant expression of a novel Ikaros isoform in normal human hemopoiesis

Murine studies implicate Ikaros proteins as regulators of hemopoiesis, particularly in the lymphoid lineages. High homology between murine and human Ikaros suggests that Ikaros expression in the two might be similar. However, initial human studies that focused on leukemia detected novel Ikaros transcripts in patient samples. Thus, novel Ikaros splice forms and DNA nonbinding isoforms were linked with malignancy. We undertook an extensive analysis of normal human Ikaros expression to determine whether novel mRNAs are expressed as proteins and the extent to which these splice variants are unique to leukemia. Here we show that both mRNA and protein for DNA nonbinding Ikaros isoforms and splice variants previously linked to leukemia are expressed in normal human cells. However, our studies identify a new Ikaros isoform not previously described in mouse or human. This isoform is the predominant Ikaros protein in normal human cells, but not in leukemia cell lines.

Analysis of nonvolatile species in a complex matrix by headspace gas chromatography

This study developed a phase reaction conversion (PRC) headspace gas chromatographic (HS-GC) technique for the measurements of nonvolatile species in liquid or solid samples. The technique is demonstrated by the measurements of carbonate in aqueous carbonate solutions and in kraft pulp mill liquor samples. A very small amount of sulfuric acid (volume of 0.5 ml, concentration of 2 mol/l) is used to acidify a sample of less than 300 microl in volume and convert the dissolved carbonate into carbon dioxide (gas) in a sample vial (reactor) that is analyzed by thermal conductivity detection through a headspace sampler. The carbonate concentrations measured by PRC-HS-GC in seven kraft liquor samples agree very well with those measured using a coulometric and a titrametric method. Simultaneous analysis of multiple species was also conducted to demonstrate the versatility of the method. The present method is very simple, rapid, reliable, accurate, and fully automated. It can be applied to analyze other nonvolatile species in various industrial and environmental samples.

Dynamical decimation renormalization-group technique: kinetic gaussian model on nonbranching, branching, and multibranching koch curves

A generalizing formulation of dynamical real-space renormalization that is appropriate for arbitrary spin systems is suggested. The alternative version replaces single-spin flipping Glauber dynamics with single-spin transition dynamics. As an application, in this paper we mainly investigate the critical slowing down of the Gaussian spin model on three fractal lattices, including nonbranching, branching, and multibranching Koch curves. The dynamical critical exponent z is calculated for these lattices using an exact decimation renormalization transformation in the assumption of the magneticlike perturbation, and a universal result z=1/nu is found.

Solvable kinetic gaussian model in an external field

In this paper, the single-spin transition dynamics is used to investigate the kinetic Gaussian model in a periodic external field. We first derive the fundamental dynamic equations, and then treat an isotropic d-dimensional hypercubic lattice Gaussian spin system with Fourier's transformation method. We obtain exactly the local magnetization and the equal-time pair-correlation function. The critical characteristics of the dynamical relaxation tau(q), the complex susceptibility chi(omega,q), and the dynamical response are discussed. The results show that the time evolution of the dynamical quantities and the dynamical responses of the system strongly depend on the frequency and the wave vector of the external field.

The pharmacological and functional characteristics of the serotonin 5-HT(3A) receptor are specifically modified by a 5-HT(3B) receptor subunit

While homomers containing 5-HT(3A) subunits form functional ligand-gated serotonin (5-HT) receptors in heterologous expression systems (Jackson, M. B., and Yakel, J. L. (1995) Annu. Rev. Physiol. 57, 447-468; Lambert, J. J., Peters, J. A., and Hope, A. G. (1995) in Ligand-Voltage-Gated Ion Channels (North, R., ed) pp. 177-211, CRC Press, Inc., Boca Raton, FL), it has been proposed that native receptors may exist as heteromers (Fletcher, S., and Barnes, N. M. (1998) Trends Pharmacol. Sci. 19, 212-215). We report the cloning of a subunit 5-HT(3B) with approximately 44% amino acid identity to 5-HT(3A) that specifically modified 5-HT(3A) receptor kinetics, voltage dependence, and pharmacology. Co-expression of 5-HT(3B) with 5-HT(3A) modified the duration of 5-HT(3) receptor agonist-induced responses, linearized the current-voltage relationship, increased agonist and antagonist affinity, and reduced cooperativity between subunits. Reverse transcriptase-polymerase chain reaction in situ hybridization revealed co-localization of both 5-HT(3B) and 5-HT(3A) in a population of neurons in the amygdala, telencephalon, and entorhinal cortex. Furthermore, 5-HT(3A) and 5-HT(3B) mRNAs were expressed in spleen and intestine. Our data suggest that 5-HT(3B) might contribute to tissue-specific functional changes in 5-HT(3)-mediated signaling and/or modulation.

[Morphological changes and electrophysiological study of motor neuron of spinal cord following delayed repair of peripheral nerve injury]

OBJECTIVE

Following the delayed repair of peripheral nerve injury, the cell number of anterior horn of the spinal cord and its ultrastructural changes, motorneuron and its electrophysiological changes were investigated.

METHODS

In 16 rabbits the common peroneal nerves of both sides being transected one year later were divided into four groups randomly: the degeneration group and regeneration of 1, 3 and 5 months groups. Another 4 rabbits were used for control. All transected common peroneal nerves underwent epineural suture except for the degeneration group the electrophysiological examination was carried out at 1, 3 and 5 months postoperatively. Retrograde labelling of the anterior horn cells was demonstrated and the cells were observed under light and electronmicroscope.

RESULTS

1. The number of labelled anterior horn cell in the spinal cord was 45% of the normal population after denervation for one year (P < 0.01). The number of labelled cells increased steadily from 48% to 57% and 68% of normal values at 1, 3 and 5 months following delayed nerve repair (P < 0.01). 2. The ultrastructure of the anterior horn cells of the recover gradually after repair. 3. With the progress of regeneration the latency become shortened, the conduction velocity was increased, the amplitude of action potential was increased.

CONCLUSION

Following delayed repair of injury of peripheral nerve, the morphology of anterior horn cells of spinal cord and electrophysiological display all revealed evidence of regeneration, thus the late repair of injury of peripheral nerve was valid.

Computer modeling of the effects of aortic valve stenosis and arterial system afterload on left ventricular hypertrophy

The degree of left ventricular hypertrophy is generally thought to reflect the severity of aortic stenosis. However, the compounded influence of arterial system load is poorly understood. We developed a computer model to investigate the effects of aortic valve stenosis in combination with various systemic arterial parameters in the development of left ventricular hypertrophy. Data show that an increased peripheral resistance and/or aortic valve resistance, results in an increase in left ventricular wall thickness and mass, while peak systolic wall stress remains constant. Changing arterial compliance to above normal level would not induce significant changes in wall thickness, while reduction in arterial compliance below normal would cause an increase in ventricular wall thickness. When a double load is imposed on the left ventricle by way of a stenotic valve and an increased arterial afterload, a greater and an aggregated increase in wall thickness results, hastening the hypertrophic process.

Intertransverse approach for extraforaminal herniations

STUDY DESIGN

This case report illustrates three patients with extraforaminal disc herniation in the lumbar spine.

OBJECTIVES

Treatment consisted of discectomy through an intertransverse approach.

SUMMARY OF BACKGROUND DATA

The surgical treatment of lumbar disc herniation has been well studied and reported in the literature. Laminectomy, foraminotomy, and facetectomy have traditionally been used for extraforaminal disc herniation. Intertransverse discectomy used in these three patients confirms the benefits of this approach.

SURGICAL METHOD

A midline incision was made, and the paraspinous muscles on the affected side were detached to expose the appropriate laminae, facets, transverse processes, and intertransverse ligament. After resecting the ligament and retracting the compressed spinal nerve outside the facet, the nucleus pulposus was removed.

RESULTS

Postoperative results were satisfactory. Weakness and low back and leg pain disappeared rapidly. The three patients returned to work 2-3 months postoperatively.

CONCLUSIONS

The patho-anatomical characteristic of the entity is compression of the spinal nerve outside the foramen. Intertransverse discectomy is a rational technique-its advantages are that the spinal canal is not opened, spine stability is maintained, and multiple disc herniation can be managed through a single posterior midline incision.

Acute inflammatory reaction after myocardial ischemic injury and reperfusion. Development and use of a neutrophil-specific antibody

Reperfusion of the infarcted canine myocardium after 1 hour of ischemia is associated with an acute inflammatory infiltrate at the border of the infarct. In this paper, we demonstrate that early margination and emigration of neutrophils originate in thin-walled (approximately 5 micrometers) venous cisterns that average 200 micrometers in length and vary from 10 to 70 micrometers in width and show strong constitutive expression of both ICAM-1 and P-selectin; this class of vessels (venous cisterns) appears to be a unique feature in heart. A monoclonal antibody (SG8H6) with specificity for canine neutrophils was developed that allowed much more sensitive immunohistochemical detection of neutrophils in tissue and allowed us to follow tissue infiltration with time. Samples from 1 hour of reperfusion revealed dense margination and substantial emigration of neutrophils associated with the venous cisterns and collecting venules. By 2 hours, there was intense local emigration to the extravascular space between cardiac myocytes. By 3 hours, the infiltrate extended deeper into the infarct, and there was a continuous border zone of neutrophil infiltration that overlapped a region where intact cardiac myocytes strongly expressed ICAM-1 mRNA and extended into the necrotic tissue. At later times, neutrophil migration into infarcted tissue continued to progress. Neutrophil transmigration into reperfused myocardium is more extensive than previously described, and its extravascular distribution during early reperfusion is primarily in the viable border zone of the myocardium where myocyte ICAM-1 mRNA is found. These data are compatible with the hypothesis that extravascular neutrophils may participate in reperfusion injury.

Preconditioning rabbit cardiomyocytes: role of pH, vacuolar proton ATPase, and apoptosis

Ischemic preconditioning signals through protein kinase C (PKC) to protect against myocardial infarction. This protection is characterized by diminished intracellular acidification. Acidification is also a feature of apoptosis, and several agents act to prevent apoptosis by preventing acidification through activation of ion channels and pumps to promote cytoplasmic alkalinization. We characterized metabolic inhibition, recovery, and preconditioning through a PKC-dependent pathway in cardiomyocytes isolated from adult rabbit hearts. Preconditioning reduced loss of viability assessed by morphology and reduced DNA nicking. Blockade of the vacuolar proton ATPase (VPATPase) prevented the effect of preconditioning to reduce metabolic inhibition-induced acidosis, loss of viability, and DNA nicking. The beneficial effect of Na+/H+ exchange inhibition, which is thought to be effective through reduced intracellular Na+ and Ca++, was also abrogated by VPATPase blockade, suggesting that acidification even in the absence of Na+/H+ exchange may lead to cell death. We conclude that a target of PKC in mediating preconditioning is activation of the VPATPase with resultant attenuation of intracellular acidification during metabolic inhibition. Inhibition of the "death protease," interleukin-1-beta converting enzyme or related enzymes, also protected against the injury that followed metabolic inhibition. This observation, coupled with the detection of DNA nicking in cells subjected to metabolic inhibition, suggests that apoptotic cell death may be preventable in this model of ischemia/reperfusion injury.

Elevated levels of plasminogen activator inhibitor-1 may account for the altered fibrinolysis by keloid fibroblasts

Using a 3-dimensional fibrin gel model system simulating fibroplasia of wound repair, we investigated the interaction between keloid fibroblasts and fibrin matrix and compared it with that of normal fibroblasts. Normal skin fibroblasts caused fibrin gel degradation under serum-free conditions, whereas keloid fibroblasts did not cause microscopically detectable gel degradation. Fibrin gel degradation occurred through plasmin-mediated fibrinolysis, which was initiated by fibroblasts exhibited high uPA but low plasminogen activator inhibitor-1 (PAI-1) activities, and transforming growth factor-beta 1 prevented fibrinolysis of normal fibroblasts by upregulating PAI-1 while downregulating uPA activities. In contrast, keloid fibroblasts exhibited an intrinsically high level of PAI-1 and a low level of uPA. This change in the ratio of activator and inhibitor activities was attributed to altered fibrin degradation by keloid fibroblasts. The PAI-1 increase was also demonstrated at the RNA level by Northern analysis. In terms of the pivotal role of the plasmin/plasminogen activator system in matrix remodeling, the elevated PAI-1 level exhibited by keloid fibroblasts may have significant consequences not only in altered fibrin degradation, but also in subsequent repair steps that lead to keloids and fibrosis.

Cardiac allograft survival in mice deficient in intercellular adhesion molecule-1

BACKGROUND

Intercellular adhesion molecule-1 (ICAM-1, CD54) is a cell adhesion molecule that interacts with the leukocyte beta 2 integrins, lymphocyte function-associated antigen-1, and macrophage antigen-1. ICAM-1 is postulated to play a key role in several cell-cell interactions that are important in allograft rejection, including antigen presentation, transendothelial migration of leukocytes, and leukocyte-medicated myocyte injury.

METHODS AND RESULTS

Mice homozygous for a gene-targeted mutation of ICAM-1 were used in two different cardiac transplant models to further define the role of ICAM-1 in the process of allograft rejection. In the first model, hearts from newborn mice were implanted in the ear pinnae of H-2-incompatible recipients. In the second model, intra-abdominal transplantation by direct vascular anastomosis was performed. Time to rejection was defined by the loss of pulsatile activity assessed by visual inspection in the ear model or by cessation of palpable cardiac impulse in the abdominal model. Allograft survival did not differ significantly between control groups that express normal levels of ICAM-1 and those groups using ICAM-1-deficient mutants as either donors or recipients. Histological examination of rejection of both normal and mutant (ICAM-1-deficient) cardiac allografts revealed similar patterns of infiltration of mononuclear and granulocytic leukocytes and myocyte necrosis. Immunostaining with anti-ICAM-1 antibodies showed ICAM-1-positive infiltrating cells in both mutant (ICAM-1-deficient) and normal allografts, with the graft endothelium negative for ICAM-1 staining in the mutant allografts.

CONCLUSIONS

The absence of surface expression of ICAM-1 in the donor allograft or recipient is insufficient to produce a significant impact on cardiac allograft survival. This study highlights the need to understand more precisely the mechanism of action whereby monoclonal antibodies to ICAM-1 prolong cardiac allograft survival before new therapeutic strategies based on gene transfer technology or small molecule inhibitors are developed. Mutant mice with targeted mutations in cell adhesion molecules provide powerful tools to study the complex role that cell adhesion molecules play in the cellular interactions between donor graft tissue and the recipient that culminate in graft rejection.

Cell acidification in apoptosis: granulocyte colony-stimulating factor delays programmed cell death in neutrophils by up-regulating the vacuolar H(+)-ATPase

Neutrophils in tissue culture spontaneously undergo programmed cell death (apoptosis), a process characterized by well-defined morphological alterations affecting the cell nucleus. We found that these morphological changes were preceded by intracellular acidification and that acidification and the apoptotic changes in nuclear morphology were both delayed by granulocyte colony-stimulating factor (G-CSF). Among the agents that defend neutrophils against intracellular acidification is a vacuolar H(+)-ATPase that pumps protons out of the cytosol. When this proton pump was inhibited by bafilomycin A1, G-CSF no longer protected the neutrophils against apoptosis. We conclude that G-CSF delays apoptosis in neutrophils by up-regulating the cells' vacuolar H(+)-ATPase and that intracellular acidification is an early event in the apoptosis program.

[The effects of Salvia miltiorrhizae Bge and Ligustrazine on thromboxane A2 and prostacyclin in pregnancy induced hypertension]

The clinical efficiency and mechanism of traditional Chinese medicinal herb Salvia Miltiorrhizae Bge (SMB) and Ligustrazine (L) on pregnancy induced hypertension (PIH) were studied in 30 patients. Before and after the administration of SMB and L, the following parameters: mean arterial pressure (MAP), proteinuria, levels of Thromboxane A2 (TXA2) and Prostacyclin (PGI2) were observed. TXA2 and PGI2 were measured by their stable hydration products Thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) by an established radioimmunoassay. The results of treatment were compared with the base line values and showed as follows: MAP and proteinuria decreased significantly (P < 0.05); no marked difference existed in TXB2; the level of 6-keto-PGF1 alpha increased significantly (P < 0.05); the rate of TXB2/6-keto-PGF1 alpha decreased significantly (P < 0.05). The results suggested that SMB and L can invigorate blood circulation by decreasing vasoconstriction.

[Effects of extracts from Phyllanthus urinaria L. on HBsAg production in PLC/PRF/5 cell line]

Experiment on the effect of extracts from Phyllanthus urinaria on HBsAg production in PLC/PRF/5 human hepatoma cell line showed that the production was decreased markedly 48 hours after the treatment of cells with 2-4 mg/ml Phyllanthus urinaria, especially in combination with 10(-5) mol/L of Ara-A. The decrease of extracellular HB-sAg excretion seems to stem from the inhibition of intracellular HBsAg formation.

[The association of human leucocyte antigen (HLA) with posthepatitic cirrhosis]

HLA class I and class II antigens from 61 patients with posthepatitic cirrhosis and 29 HBsAg healthy carrier were examined by using the standard serum including 105 specificities in A, B, C, DQ and DR Loci of HLA provided by the 11th International Histocompatibility Workshop. The results showed the frequencies of HLA-B35 and DR3 were elevated in posthepatitic cirrhosis group as compared with the healthy control group (P < 0.001). The data showed that the frequencies of HLA-B8, C1 were significantly increased, while those of HLA--DR8 more significantly decreased in posthepatitic cirrhotic patients than in health virus carriers. Compared to the healthy controls, however, the frequencies of all 105 HLA specificities examined were identical to healthy carriers.

[The effect of Coptis chinensis on lipid peroxidation and antioxidases activity in rats]

In order to make a systematic study of the effect of Coptis chinensis on free radicals, the authors used the method that the drug and the brain homogenate of rat were mixed and incubated to investigate the effect of Coptis on lipid peroxidation. The result showed that the malondialdehyde (MDA) product of rat brain homogenate inhibited by 5% Coptis was significantly different from control (P < 0.001). On the basis of the above-mentioned results, the effect of Coptis on lipid peroxidation and diabetes of rats induced by alloxan was investigated. The result showed: (1) The MDA product of both pancreas and liver homogenate in Coptis group was significantly less than that in control and alloxan group (P < 0.01, P < 0.05). (2) Superoxide dismutases (SODs) in erythrocytes activity was the same for all groups (P > 0.50). (3) The blood catalase (CAT) activity in alloxan group markedly decreased compared with control group (P < 0.05), but no significant change between Coptis and alloxan group (P > 0.05). (4) The value of serum glucose in alloxan group was significantly increased in comparing with control group (P < 0.05). There was a trend to decrease the value of serum glucose in Coptis group compared with alloxan group, but no significant difference between two groups (P > 0.05). The experiment indicated that there was very strong inhibitory effect of Coptis to the lipid peroxidation in vitro and in vivo. Coptis could protect rat from diabetes inducing by alloxan and that probably was due to the fact that Coptis was able to inhibit alloxan inducing free radicals.