Amino acid catabolism and antibiotic synthesis: valine is a source of precursors for macrolide biosynthesis in Streptomyces ambofaciens and Streptomyces fradiae

Targeted inactivation of the valine (branched-chain amino acid) dehydrogenase gene (vdh) was used to study the role of valine catabolism in the production of tylosin in Streptomyces fradiae and spiramycin in Streptomyces ambofaciens. The deduced products of the vdh genes, cloned and sequenced from S. fradiae C373.1 and S. ambofaciens ATCC 15154, are approximately 80% identical over all 363 amino acids and 96% identical over a span of the first N-terminal 107 amino acids, respectively, to the deduced product of the Streptomyces coelicolor vdh gene. The organization of the regions flanking the vdh genes is the same in all three species. Inactivation of the genomic copy of the vdh gene in S. fradiae and S. ambofaciens by insertion of a hygromycin resistance (hyg) gene caused loss of the valine dehydrogenase (Vdh) activity, and thus only one enzyme is responsible for the Vdh activity in these organisms. Analysis of the culture broth by bioassay revealed that the vdh::hyg mutants produce an approximately sixfold-lower level of tylosin and an approximately fourfold-lower level of spiramycin than the wild-type S. fradiae and S. ambofaciens strains, while maintaining essentially identical growth in a defined minimal medium with either 25 mM ammonium ion or 0.05% asparagine as the nitrogen source. The addition of the valine catabolite, propionate or isobutyrate, and introduction of the wild-type vdh gene back to each vdh::hyg mutant reversed the negative effect of the vdh::hyg mutation on spiramycin and tylosin production. These data show that the catabolism of valine is a major source of fatty acid precursors for macrolide biosynthesis under defined growth conditions and imply that amino acid catabolism is a vital source of certain antibiotic precursors in actinomycetes.

Two-dimensional optical wavelet transform in space domain and its performance analysis

A new architecture of an optical wavelet transform system with a lenslet array is proposed, and its optical performance and optical limits are analyzed.

The genetic basis of precursor supply for the biosynthesis of macrolide and polyether antibiotics

Macrolide and polyether biosynthesis in actinomycetes is regulated at the level of precursor supply by effects of nutrients on the sources of the low-molecular-weight fatty acids used to build the carbon framework of these antibiotics. Ammonium ion appears to suppress the first enzymes of valine and threonine catabolism and also inhibits their activity. Disruption of the valine dehydrogenase (vdh) gene of Streptomyces coelicolor destroys its ability to grow on branched-chain amino acids as the sole nitrogen source in a minimal medium but has no effect on the biosynthesis of the acetate-derived antibiotic, actinorhodin. Expression of the vdh gene is repressed by > 25 mM ammonium ion or glucose but not by valine, glycerol, or maltose. Vdh enzyme activity is stimulated by valine induction. These results suggest that the inhibition of valine catabolism by ammonium and/or glucose could explain why macrolide production is inhibited by ammonium ion.

The sequence of the groES and groEL genes from the mouse pneumonitis agent of Chlamydia trachomatis

The co-transcribed structural genes, groES and groEL, of the groE stress response operon from Chlamydia trachomatis mouse pneumonitis (MoPn), were cloned and sequenced. The calculated molecular masses of the encoded heat-shock proteins (Hsp), a small Hsp (GroES) and Hsp60 (GroEL), are 11,089 and 58,367 Da, respectively. By comparison with other known chlamydial groES and groEL sequences, there is 89 and 94% nucleotide (nt) identity with C. trachomatis human strains (serovars A and L2), 77 and 82% with C. psittaci strain GPIC, and 75 and 80% with C. pneumoniae isolate AR-39. At the amino-acid level, the MoPn Hsp60 shows a 99% identity with those from C. trachomatis human strains. In a mouse model, MoPn Hsp60 could prove useful in deciphering the pathogenesis of human chlamydial diseases.

Effects of captopril and nadolol on renal hemodynamics in patients with essential hypertension

The randomized single-blind study was designed to compare the effects of captopril (Cap) and nadolol (Nad) on renal hemodynamics in 60 patients with essential hypertension. They were divided into two groups at random. Cap was given in dosage of 37.5-75 mg/d per os and Nad 40-80 mg/d. The results show that both drugs increase the blood volume distributed to the kidneys from cardiac output (renal blood flow/cardiac output), Cap increasing 10% (P < 0.05) and Nad 8% (P < 0.05). Renal vascular resistance (RVR) is lowered by the two drugs, 13% (P < 0.05) by Cap and 11% (P < 0.05) by Nad. These suggest that both drugs facilitate the maintenance of renal blood circulation in patients with essential hypertension, being beneficial for long-term treatment of hypertension.

Cloning, sequencing, and expression in Escherichia coli of the gene encoding a 45-kilodalton protein, elongation factor Tu, from Chlamydia trachomatis serovar F

The gene encoding a 45-kDa protein (45K) of Chlamydia trachomatis serovar F was cloned, sequenced, and overexpressed in Escherichia coli. Alignment of the deduced peptide sequence with E. coli elongation factor Tu (EF-Tu) demonstrated 69% identity. The 45K was recognized by a Chlamydia genus-specific monoclonal antibody GP-45 and cross-reacted with a monospecific polyclonal antibody to E. coli EF-Tu. Purified recombinant 45K has the capability to bind GDP, and the binding was enhanced in the presence of E. coli elongation factor Ts (EF-Ts). The GDP binding was specifically inhibited by the monoclonal antibody GP-45. These data suggest that the 45K is a chlamydial EF-Tu, and it forms a functional complex with E. coli EF-Ts protein.

Kinetics of irreversible inhibition of yeast alcohol dehydrogenase during modification by o-phthaldehyde

The kinetic theory of the substrate reaction during irreversible inhibition of enzyme activity described previously has been applied to a study on the kinetics of the course of inactivation of yeast alcohol dehydrogenase (YADH) by o-phthaldehyde (OPTA). The microscopic constants for the reaction of the inactivators with the free enzyme and with the enzyme-substrate complexes were determined. The inactivation is a monophasic pseudo-first-order reaction with OPTA. The apparent rate constant A is independent of the OPTA concentration, indicating that the inactivation is a noncomplexing inhibition. The marked protective effect of substrates on the inactivation of YADH by OPTA has been observed. This result suggests that the modification of the enzyme by OPTA may occur at the active site.

Comparison of the major outer-membrane protein (MOMP) gene of mouse pneumonitis (MoPn) and hamster SFPD strains of Chlamydia trachomatis with other Chlamydia strains

Restriction fragments containing the major outer-membrane protein (MOMP) gene from two nonhuman (rodent) strains of Chlamydia trachomatis, the mouse pneumonitis (MoPn) strain and the SFPD strain isolated from hamsters with transmissible proliferative ileitis, were cloned and sequenced. The MOMP genes of both MoPn and SFPD encode an identical 22-amino acid leader peptide and mature polypeptides of 365 and 382 amino acids, respectively. Alignment of the MOMP genes of the two rodent strains revealed 91% identity. By comparison with other known chlamydial MOMP gene sequences, there was 80%-83% identity with human biovars strains of C. trachomatis, and there was 69%-70% identity with C. psittaci and C. pneumoniae strains. The main differences in these sequences were clustered into four variable domains. A minimum-length evolutionary tree was constructed on the basis of the MOMP gene variable positions by using PIMA package software. The minimum mutation distances indicated that (i) the MOMP genes of all chlamydial strains may have evolved from a common ancestor; (ii) all the strains of C. trachomatis compose one of the subtrees, and strains of C. psittaci and C. pneumoniae compose the other subtree; and (iii) in the C. trachomatis subtree, the human and the rodent strains are divided into two clusters. The branching pattern of this evolutionary tree is generally consistent with current classification based on serological, morphological, and other biological characteristics.

[Clinical investigation of erythrocyte function in patients with lung cancer]

With a yeast-erythrocyte-SPA rosette method, the function of erythrocyte immune adherence was determined in 49 cases of lung cancer, 20 cases of benign pulmonary diseases and 60 healthy persons. By means of simple morphologic method and pyrogallol autoxication method, the function of erythrocyte enhancing neutrophils phagocytosis and the activity of RBC-CuZnSOD were measured in some of these subjects. It was found that both the function of red cell immune adherence and the effect of erythrocyte enhancing phagocytosis in the patients with lung cancer were significantly weaker than in the cases of benign pulmonary diseases and the healthy subjects. The function of erythrocyte immune adherence tended to recover after effective surgical treatment. In comparison with the healthy persons, the activity of RBC-CuZnSOD was significantly lower in the patients with lung cancer. The mechanism and clinical significance of the changes in erythrocyte function were discussed.

Two methods of haploidization in pear, Pyrus communis L.: greenhouse seedling selection and in situ parthenogenesis induced by irradiated pollen

Seedlings of 12 crosses involving pear varieties or hybrids were observed for the presence of haploid plants. On the basis of phenotypic characteristics, 17 plants corresponded to the haploid condition and, of these, 12 were determined by chromosome counting to be haploid (2n=x=17). In addition, and in order to induce in situ parthenogenesis, several pear varieties were pollinated with a selected clone carrying a homozygous dominant marker gene for the colour of red. This pollen had previously been irradiated with γ-rays of cobalt 60 at 0, 200, 250 and 500 Grays. The immature embryos were cultured in vitro, whereby 1 haploid and two mixoploid plants were obtained. Numerous diploid plants with the maternal phenotype were also obtained, and their genetic origin was subsequently studied by means of isozyme analysis.

The effects of thiamin and its phosphate esters on dopamine release in the rat striatum

The effect of thiamin and its phosphate esters on dopamine (DA) release was examined in the rat striatum using an in vivo microdialysis. Intrastriatal administration of thiamin triphosphate (TTP) or thiamin diphosphate (TDP) induced DA release, but thiamin monophosphate (TMP) or thiamin did not show any change. In the absence of Ca2+ in the perfusate, TTP did not increase the DA release. omega-Conotoxin did not decrease the TTP-dependent DA release. These findings suggest that, in contrast to TMP and thiamin, TTP and TDP may play a specific role in DA release from nerve terminals.

[Hepatitis B virus DNA in the serum of anti-HBs positive persons]

In order to investigate the significance of HBV DNA in the serum of anti-HBs positive persons, the serum of 76 anti-HBs positive persons was studied for HBV DNA by means of polymerase chain reaction (PCR). The results showed that 21 (32.2%) out of 65 cases without hepatitis B vaccination were positive for HBV DNA detected with PCR (PCR-HBV DNA), but no one was positive for PCR-HBV DNA in 11 cases inoculated against hepatitis B. It was also found that 6 cases were positive for HBsAg-Ab immunocomplex in those positive for PCR-HBV DNA and the liver tissue in 2 of the 5 cases with liver-biopsy were positive for HBVAg determined with immunohistologic ABC method. We believed that persons, who acquired anti-HBs after HBV infection were different from those who were vaccinated, might carry HBV which come from the HBsAg-Ab immunocomplex and HBVAg positive hepatocytes. In addition, the study also proved that the PCR-HBV DNA positive rate correlated significantly with the anti-HBe and or anti-HBc positive rate and with the abnormal rate of liver function in the anti-HBs positive persons. It was suggested that persistent presence of HBV DNA in the bodies should be responsible for the persistent presence of anti-HBe and anti-HBc in the serum and also for the liver damage.

[Diagnostic significance of multinuclear giant cells in lymph node fine needle aspiration]

Enlarged lymph nodes, commonly seen in inflammatory or tumorous conditions, is often suspected as Hodgkin's disease in cytologic diagnosis. Twenty cases originally diagnosed as Hodgkin's disease by fine needle aspiration of lymph nodes are reported. Eighteen of these 20 cases were checked by histopathology. It was found that only 3 had reached the correct diagnosis. The authors believe that by thorough understanding of the origin and characteristics of various types of multinuclear giant cells, differentiation from Hodgkin's disease is possible.

Monoclonal antibodies define genus-specific, species-specific, and cross-reactive epitopes of the chlamydial 60-kilodalton heat shock protein (hsp60): specific immunodetection and purification of chlamydial hsp60

Ocular and urogenital tract infections with Chlamydia trachomatis can progress to chronic inflammatory diseases that produce blindness and tubal infertility. The pathophysiology of these chronic disease conditions is thought to be immunologically mediated, and the chlamydial 60-kDa heat shock protein (hsp60) has been implicated as a major target antigen that stimulates the immunopathological response. The lack of chlamydial hsp60 antibodies and purified hsp60 has severely restricted studies to define more thoroughly the role of this protein in the immunopathogenesis of chlamydial disease. We produced a panel of antichlamydial hsp60 monoclonal antibodies (MAbs) and defined their specificities by immunoblotting against lysates of C. trachomatis, C. psittaci, and six other genera of bacteria. Three patterns of anti-hsp60 immunoreactivity were observed: chlamydial species specific, chlamydial genus specific, and cross-reactive. The epitopes recognized by these MAbs were localized within the primary amino acid sequence of hsp60 by immunoblotting against recombinant amino-terminal truncated hsp60 fusion polypeptides and then precisely mapped by use of overlapping synthetic peptides. The majority of the MAbs mapped to either the amino or the carboxyl termini of hsp60. Epitopes defining all three MAb reactivities mapped within amino-terminal residues 6 to 16. Genus-specific hsp60 MAbs mapped to epitopes located within this region and to residues 17 to 28 and 177 to 189. Antichlamydial hsp60 MAbs stained inclusions as effectively as MAbs specific for the major outer membrane protein. Homogeneous preparations of full-length recombinant chlamydial hsp60 and amino-terminal truncated recombinant hsp60 polypeptides were obtained by immunoabsorption chromatography with an hsp60 MAb reactive to the carboxyl terminus of the protein. Thus, the antichlamydial MAbs described here should be extremely useful for the specific immunodetection of hsp60 in tissues from individuals having different disease manifestations and for the purification of hsp60 or truncated hsp60 polypeptides for use in serologic and lymphocyte proliferation assays. The availability of these MAbs will facilitate studies to define more precisely the role of hsp60 in the immunopathogenesis of chlamydial disease.

Fast learning in a backpropagation algorithm with a sine-type thresholding function

A new approach to learning in a multilayer neural network based on a backpropagation algorithm is presented. With a sine-type thresholding function the model is more efficient and able to learn nonnegative interconnections that are suitable for optical implementations.

Trace elements in full-term neonate hair

Proton Induced X-ray Emission (PIXE) was employed to measure simultaneously the concentration of 12 trace elements in the hair of 141 AGA newborn infants at term. Log-normal distributions were measured for all elements. There were no significant differences in trace elements in relation to sex, gestational age and body weight. The geometric means (mg/kg) were: Cr, 1.5 +/- 0.2; Mn, 1.5 +/- 0.1; Fe, 51 +/- 4; Ni, 1.0 +/- 0.2; Cu, 6.1 +/- 0.3; Zn, 133 +/- 3; As, 0.055 +/- 0.005; Se 0.81 +/- 0.05; Br, 1.3 +/- 0.1; Pb, 1.4 +/- 0.2; Rb, 0.22 +/- 0.03; and Sr, 1.5 +/- 0.2. Some direct and inverse partial correlations among elements were found at different levels of significance. Each element was significantly correlated with at least one other. Zinc and copper concentrations were lower compared to data in the literature. The high values of chromium and selenium concentrations were in agreement with previous findings. The manganese level was in accordance with previous data. The Zn/Cu ratio agreed very well with the data in the literature. This indicates that while concentration values may be subjected to large variations due to living conditions, correlations could be more stable and therefore offer insight on the regulatory mechanisms governing trace element metabolism in man.

In vitro activity of a new cephalosporin ME-1206 compared with other agents

The in vitro activity of ME-1206, a new aminothiazolyl cephalosporin that can be orally absorbed when converted to an ester, was compared with that of other beta-lactams. ME-1206 inhibited 50% of the Enterobacteriaceae at 2 micrograms/ml, similar to cefotaxime, ceftazidime, and cefixime. It did not inhibit, MIC greater than or equal to 32 micrograms/ml, Enterobacter species or Citrobacter freundii resistant to cefotaxime and ceftazidime, and it was less active than cefotaxime and ceftazidime against Serratia marcescens. Haemophilus influenzae, Neisseria gonorrhoeae, and Moraxella catarrhalis were inhibited by less than or equal to 0.25 micrograms/ml of ME-1206 inhibited hemolytic streptococci groups A, B, C, and G, MIC90 0.06 micrograms/ml, but it did not inhibit enterococci. Pseudomonas aeruginosa and other pseudomonads were resistant to ME-1206. MICs and MBCs of ME-1206 for susceptible species were within a dilution. ME-1206 was not hydrolyzed by TEM-1 or TEM-2, but was hydrolyzed by TEM-3 and TEM-5. ME-1206 was hydrolyzed by beta-lactamases of Morganella, Proteus vulgaris, and K1 of Klebsiella oxytoca, but minimally by the P99 beta-lactamase of Enterobacter cloacae. ME-1206 is comparable in in vitro activity and beta-lactamase stability to many of the current cephalosporins.

A computerized test battery for the assessment of cardiovascular reactivity

Recent evidence has suggested a possible relationship between the tendency to exhibit excessive cardiovascular reactions during psychological challenge and the risk of cardiovascular disease. Valid techniques for reliably assessing such reactions are, however, minimally available. A test battery for the assessment of cardiovascular reactivity to experimental challenge is currently being developed at the University of Pittsburgh in conjunction with the University of Miami and Duke University. An IBM-AT compatible microcomputer is being used for the concurrent collection of physiological data and presentation of the laboratory stressors. Digitized cardiovascular data being collected include EKG, Impedance Cardiogram (ICG), phonocardiogram, and a peripheral pulse wave measure. Blood pressure readings are also being collected and stored on disk. The computer presents three challenging video games, each designed to elicit cardiovascular reactions. Processing programs are being used and developed for the standardized scoring of the digitized signals. To assist in epidemiological research a mobile testing unit has been assembled for the easy administration of the test battery in varying geographical locations. The test battery being developed will increase the feasibility of epidemiological and clinical assessment of stress-induced cardiovascular responses which may substantiate a link between reactivity and cardiovascular disease.

In vitro activity of sparfloxacin

Sparfloxacin, a new fluoroquinolone, inhibited the majority of members of the family Enterobacteriaceae at less than or equal to 1 microgram/ml. It was less active than ciprofloxacin but more active than ofloxacin. Against Pseudomonas aeruginosa, it was less active than ciprofloxacin but twofold more active than ofloxacin. It inhibited Staphylococcus aureus and most Streptococcus pneumoniae and Streptococcus pyogenes isolates at 0.25 micrograms/ml, whereas ciprofloxacin and ofloxacin inhibited these isolates at 2 micrograms/ml. Bacteroides fragilis was inhibited by less than or equal to 2 micrograms/ml. Sparfloxacin was less active at an acidic pH and in the presence of Mg2+. Resistance to sparfloxacin was produced by repeated exposure, although the frequency of single-step mutants was less than 10(-9).

Optical associative memory using an orthogonalized hologram

A two-dimensional orthogonal model of optical associative memory for storage of nonnegative patterns using a single hologram is presented. Two sets of patterns after prior orthogonal processing are composed and used for hologram recording, which permits the sequential holographic recordings to be carried on spatially separated regions of the recording material. High diffraction efficiency of the hologram is achieved. Computer simulations and optical demonstrations are also given.

Antioxidation activity of tetrahydrobiopterin in pheochromocytoma PC 12 cells

Rat pheochromocytoma PC 12 cells are susceptible to the oxidative toxicity caused by H2O2, nitrofurantoin, dopamine, and xanthine/xanthine oxidase reaction. The cytotoxicities of these agents are greatly reduced by the simultaneous presence of 0.1 mM tetrahydrobiopterin (BH4), 3 units/ml horseradish peroxidase, 0.2 mM NADH, and 0.1 units/ml sheep liver dihydropteridine reductase (DHPR). Individually, BH4, NADH and DHPR have no protection against H2O2 toxicity in PC 12 cells. Peroxidase alone offers 58% of protection if cells are incubated in the medium but only 3% in Dulbecco's phosphate buffered saline. The efficiency of the BH4-mediated antioxidation system in PC 12 cells is equal to or better than ascorbic acid and catalase, depending on the source of the reactive O2 species (ROS). The reactions responsible for the BH4-antioxidation system may consist of the non-enzymatic and the peroxidase-catalyzed reduction of H2O2 to H2O by BH4 and the regeneration of BH4 by DHPR using NADH as the cofactor. The components of this defence mechanism against ROS are all normal cellular constituents and are ubiquitous in nature. This DHPR-catalyzed redox cycling of BH4 may constitute an as yet little-known antioxidation system in mammalian cells.

Fleroxacin combined with rifampin

We determined the effect of the combination of rifampin and fleroxacin against Enterobacteriaceae and streptococcal species. None of the 65 isolates tested by checkerboard assay demonstrated synergy, 12% of isolates showed an additive effect; 86.7% were indifferent, and only 1 isolate showed antagonism. The mean FIC was 1.2. When using 2 and 8 micrograms/ml of rifampin, fleroxacin MICs of 285 isolates of Enterobacteriaceae, Pseudomonas aeruginosa, Haemophilus influenzae, staphylococci, streptococci, Bacteroides, and Clostridium were not increased, but synergy was not demonstrated. Time-kill studies against Escherichia coli, P. aeruginosa, Enterobacter cloacae, Staphylococcus aureus, and Enterococcus faecalis failed to show increased killing when the two agents were present at one-half the MBC. The fleroxacin-rifampin interaction is one of indifference but provides coverage for species not adequately inhibited by fleroxacin.

Diarrhoea surveillance in children aged under 5 years in a rural area of Hebei Province, China

A surveillance of diarrhoeal diseases in children aged under five years was carried out from March 1986 to February 1987 in a rural area of Hebei Province, China. Using a cluster sampling method, 270 study children were selected from 30 villages to represent a population of 105,405. Parents noted episodes of diarrhoea in children on a calender using a given definition of diarrhoea. The findings were verified by trained village doctors and were recorded monthly in the county Health and Anti-epidemic Stations. Stools of diarrhoea-affected children were examined to detect causal agents of diarrhoea, once in each of four seasons of the year. Of the 270 children, 218 (80.74%) suffered from one or more than one attacks of diarrhoea with a 95% confidence interval between 75.94% and 85.54%. There was no death due to diarrhoea. The diarrhoeal incidence in children of 3-4-year age group was significantly less than that in the children of less than 3 years (p less than 0.05). In the children with diarrhoea, the number of mean episodes was 3.15 per child/year, and the total mean course of suffering was 14 days per child/year. The ratio of diarrhoeal episodes in spring, summer, autumn, and winter was about 2.5:5:2:1. July was the month of highest occurrence of diarrhoea (146; 21.28% of all episodes). The epidemiological parameters of the disease declined with the growing age of the children, and there was no gender-specific preponderance in the number of episodes. During the whole year, 21.7% of the diarrhoeal episodes were due to bacterial pathogens, 4% of the episodes were due to rotavirus, and 3.65% episodes were associated with the detection of Trichomonas hominis.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiple tandem promoters of the major outer membrane protein gene (omp1) of Chlamydia psittaci

The transcription of omp1, the gene encoding the major outer membrane protein, was studied for two strains of Chlamydia psittaci, guinea pig inclusion conjunctivitis (GPIC) and mouse pneumonitis (Mn). The transcriptional initiation sites for the omp1 of each strain were mapped by S1 nuclease and primer extension analyses. Three different sizes of omp1 transcripts were observed for GPIC and four were observed for Mn. The production of these transcripts appeared to be the consequence of multiple tandem promoters. The order in which the omp1 RNA transcripts appeared during the growth cycle of the C. psittaci strains was found to differ from that of C. trachomatis.