Cloning and sequence determination of a gene encoding an osmotin-like protein from strawberry (Fragaria X ananassa Duch.)

Osmotin and osmotin-like proteins (OLPs) are pathogenesis-related (PR) proteins, whose synthesis is normally stimulated upon infection of plants by pathogens. A strawberry genomic clone containing an osmotin-like protein (OLP) gene was isolated and sequenced. This clone contains an open reading frame of 681 nucleotides without any intron. The predicted amino acid sequence of the protein shares high degrees of homology with a number of other OLPs and related proteins, of which several are known to have antifungal activities. Southern hybridization analysis of strawberry genomic DNA suggested that the OLP is coded by a multi-gene family. Results from reverse transcriptase-polymerase chain reaction indicated that this OLP gene is expressed in uninfected strawberry plants.

Analgesia and COX-2 inhibition

While non-steroidal anti-inflammatory drugs (NSAIDs) are the mainstay of therapy for the management of acute pain and rheumatoid arthritis, toxicity associated with chronic administration limits their benefit-to-risk relationship in many patients. A series of studies is reviewed that assesses the relationship between cytokines released at the site of tissue injury and NSAID analgesia, and the in vivo selectivity of a selective cyclooxygenase (COX)-2 inhibitor (celecoxib) in comparison to a dual COX-1/COX-2 inhibitor (ketorolac). Three replicate studies in the oral surgery model of acute pain used submucosal microdialysis sample collection for the measurement of prostaglandin E2 (PGE2; a product of both COX-1 and COX-2) and thromboxane B2 (as a biomarker for COX-1 activity) with parallel assessments of pain. The time course of PGE2 production was consistent with early release due to COX-1 activity followed by increased production 2-3 hours after surgery, consistent with COX-2 expression. Ketorolac 30 mg at pain onset suppressed both pain and peripheral PGE2 levels. Ketorolac 1 mg either at the site of injury or intramuscularly also produced analgesia but without any effect on peripheral PGE2 levels. Celecoxib selectively suppressed PGE2 but not TxB2 at time points consistent with COX-2 activity, while producing analgesia. These studies demonstrate the ability to assess the time course and selective effects of COX-2 inhibitors in vivo and suggest that suppression of COX-2 mediated PGE2 is temporally related to NSAID analgesia.

Molecular cloning, nucleotide sequence, and expression of genes encoding a polycyclic aromatic ring dioxygenase from Mycobacterium sp. strain PYR-1

Mycobacterium sp. strain PYR-1 degrades high-molecular-weight polycyclic hydrocarbons (PAHs) primarily through the introduction of both atoms of molecular oxygen by a dioxygenase. To clone the dioxygenase genes involved in PAH degradation, two-dimensional (2D) gel electrophoresis of PAH-induced proteins from cultures of Mycobacterium sp. strain PYR-1 was used to detect proteins that increased after phenanthrene, dibenzothiophene, and pyrene exposure. Comparison of proteins from induced and uninduced cultures on 2D gels indicated that at least six major proteins were expressed (105, 81, 52, 50, 43, and 13 kDa). The N-terminal sequence of the 50-kDa protein was similar to those of other dioxygenases. A digoxigenin-labeled oligonucleotide probe designed from this protein sequence was used to screen dioxygenase-positive clones from a genomic library of Mycobacterium sp. strain PYR-1. Three clones, each containing a 5,288-bp DNA insert with three genes of the dioxygenase system, were obtained. The genes in the DNA insert, from the 5' to the 3' direction, were a dehydrogenase, the dioxygenase small (beta)-subunit, and the dioxygenase large (alpha)-subunit genes, arranged in a sequence different from those of genes encoding other bacterial dioxygenase systems. Phylogenetic analysis showed that the large alpha subunit did not cluster with most of the known alpha-subunit sequences but rather with three newly described alpha subunits of dioxygenases from Rhodococcus spp. and Nocardioides spp. The genes from Mycobacterium sp. strain PYR-1 were subcloned and overexpressed in Escherichia coli with the pBAD/ThioFusion system. The functionality of the genes for PAH degradation was confirmed in a phagemid clone containing all three genes, as well as in plasmid subclones containing the two genes encoding the dioxygenase subunits.

An improved heat pulse method to measure low and reverse rates of sap flow in woody plants

The compensation heat pulse method (CHPM) is of limited value for measuring low rates of sap flow in woody plants. Recent application of the CHPM to woody roots has further illustrated some of the constraints of this technique. Here we present an improved heat pulse method, termed the heat ratio method (HRM), to measure low and reverse rates of sap flow in woody plants. The HRM has several important advantages over the CHPM, including improved measurement range and resolution, protocols to correct for physical and thermal errors in sensor deployment, and a simple linear function to describe wound effects. We describe the theory and methodological protocols of the HRM, provide wound correction coefficients, and validate the reliability and accuracy of the technique against gravimetric measurements of transpiration.

Physiological regulation of the immunological synapse by agrin

T cell activation is dependent on both a primary signal delivered through the T cell receptor and a secondary costimulatory signal mediated by coreceptors. Although controversial, costimulation is thought to act through the specific redistribution and clustering of membrane and intracellular kinase-rich lipid raft microdomains at the contact site between T cells and antigen-presenting cells. This site has been termed the immunological synapse. Endogenous mediators of raft clustering in lymphocytes have not been identified, although they are essential for T cell activation. We now demonstrate that agrin, an aggregating protein crucial for formation of the neuromuscular junction, is also expressed in lymphocytes and is important in reorganization of membrane lipid microdomains and setting the threshold for T cell signaling. Our data show that agrin induces the aggregation of signaling proteins and the creation of signaling domains in both immune and nervous systems through a common lipid raft pathway.

Antimalarial, antiviral, and antitoxoplasmosis norsesterterpene peroxide acids from the Red Sea sponge Diacarnus erythraeanus

A new norsesterterpene acid, named muqubilone (1), along with the known sigmosceptrellin-B and muqubilin were isolated from the Red Sea sponge Diacarnus erythraeanus. The structure determination of 1 was based primarily on 1D and 2D NMR analyses. Sigmosceptrellin-B exhibits significant in vitro antimalarial activity against Plasmodium falciparum (D6 and W2 clones) with IC(50) values of 1200 and 3400 ng/mL, respectively. Muqubilin and 1 show in vitro antiviral activity against herpes simplex type 1 (HSV-1) with ED(50) values of 7.5 and 30 microg/mL, respectively. Muqubilin and sigmosceptrellin-B display potent in vitro activity against Toxoplasma gondii at a concentration of 0.1 microM without significant toxicity.

Effects of multiple exposures of small doses of Pembina Cardium crude oil and diesel in rats

In lands used for agricultural purposes, petroleum- or diesel-contaminated wastes and accidental spills of crude oil at some drilling sites pose exposure risks for occupational public, livestock, and wildlife. This study has assessed the effects of an Alberta crude oil, Pembina Cardium crude oil (PCCO), and a commercial diesel fuel #2 (CDF-2) in Sprague-Dawley rats after repeated exposures at small dose levels. Rats were given by gavage on day 1, 3, 5, and 8 specified dosages of either the control vehicle, methylcellulose (MC) (1.25 ml/kg), or PCCO (0.25-1.25 ml/kg), or CDF-2 (1.25 ml/kg). Exposure of rats to these dose levels of the test substances caused no overt symptoms of intoxication. A small but statistically significant increase in liver somatic index was observed in rats exposed to 1.25 ml/kg doses of PCCO and CDF-2; however, kidney somatic index was not significantly affected by these treatments. Blood analyses for hematological and clinical indicators of systemic impairments did not show any significant changes (p > 0.05) between the control and PCCO- or CDF-2-exposed rats. Biochemical assessment of liver and kidney tissues showed that compared to the control group, the PCCO- and CDF-2-exposed groups had a marked and significant increase (p < 0.05) in the hepatic activity of ethoxyresorufin-O-deethylase (EROD, a cytochrome P-450 [CYP] 1A1/A2-linked enzyme). In PCCO-exposed rats, the induction of EROD was dose-dependent. Exposure of rats with PCCO and CDF-2 also caused dose-related increases from the unexposed (control) or MC dosed rats in (1) hepatic activities of aryl hydrocarbon hydroxylase (AHH, a CYP 1A1-linked enzyme), ethoxycoumarin-O-deethylase (ECOD, a CYP 2B/1A-linked enzyme), glutathione transferase (GT), and NADPH-catalyzed microsomal lipid peroxidation; and (ii) ECOD activity in kidneys. The induction of hepatic CYP-linked enzymatic activities by PCCO and CDF-2 could be due to de novo synthesis of selected isoforms, as evidenced by the relative differences in the inhibition of EROD activity with 7,8-benzoflavone or metyrapone.

DNA packaging and developmental intermediates of a broad host range Vibrio vulnificus bacteriophage 71A-6

The structural intermediates in the capsid assembly and DNA packaging pathway of Vibrio vulnificus bacteriophage 71A-6, a rod-shaped double-stranded DNA podovirus, were isolated by ultracentrifugation and studied by electron microscopy, SDS-PAGE and pulsed-field gel electrophoretic analysis. Bacteriophage 71A-6 synthesized rod-shaped capsids (mean length=200+/-8 nm; mean width=47+/-3 nm n=50) during its development. Several host proteins that probably help in the assembly and maturation of the capsids were attached to these capsids as spherical structures. A capsid-DNA or DNA packaging complex that consisted of the mature capsids, DNA and a 42.5-kDa protein was also isolated. The size of the capsids increased in length and decreased in width (mean length=220+/-8 nm; mean width=45+/-3 nm n=50) either during or after the DNA packaging. The capsid fractions contained about 12 phage structural proteins and eight host proteins. At least three proteins were tentatively identified: a 38.5-kDa major capsid protein, a 35.2-kDa tail protein and 42.5-kDa packaging initiator or terminator protein. The size of the bacteriophage 71A-6 genome was determined to be 143.0-kb by pulsed-field gel electrophoresis. The total mass of all the mature phage proteins corresponded to only 14.0% of the coding capacity of phage genome.

New manzamine alkaloids with potent activity against infectious diseases

The isolation of the new enantiomers of 8-hydroxymanzamine A (1), manzamine F (2), along with the unprecedented manzamine dimer, neo-kauluamine from an undescribed genus of Indo-Pacific sponge (family Petrosiidae, order Haplosclerida) is reported. The relative stereochemistry of neo-kauluamine was established through detailed analysis of NOE-correlations combined with molecular modeling. The significance of the manzamines as in vivo antimalarial agents with superior activity to the clinically used drugs artemisinin and chloroquine is discussed along with the activity in vitro against the AIDS-opportunistic infectious diseases tuberculosis and toxoplasmosis. Reexamination of the sponges identified as Prianos, and Pachypellina, in earlier publications has confirmed that these are members of the same genus as the sponge described here, but differ at the species level.

Purification, characterization, and molecular cloning of a chitinase from the seeds of Benincasa hispida

A chitinase was purified from the seeds of Benincasa hispida, a medicinal plant also called white gourd, and a member of the Cucurbitaceae family. Purification was done by using a procedure consisting of only two fractionation steps: an acid denaturation step followed by ion-exchange chromatography. The sequence of the N-terminal forty amino acid residues was analyzed and the sequence indicated that the enzyme is a class III chitinase. The enzyme, which is a basic chitinase, is one of at least five chitinases detected in the seed extract of B. hispida. Like other class III chitinases, this enzyme also has lysozyme activity. A genomic clone of the gene encoding the enzyme was isolated and sequenced. The gene has the potential to encode a protein of 301 amino acid residues. The deduced amino acid sequence of the protein, as expected from the N-terminal amino acid sequence, shares high degrees of similarity with other class III chitinases.

Activity of gatifloxacin alone or in combination with pyrimethamine or gamma interferon against Toxoplasma gondii

The activity of gatifloxacin against Toxoplasma gondii, either alone or in combination with pyrimethamine or gamma interferon (IFN-gamma), was examined in vitro and in vivo. In vitro, gatifloxacin significantly inhibited intracellular replication of tachyzoites of the RH strain with a 50% inhibitory concentration of 0.21 microg/ml at 48 h after addition of the drug to the cultures. Toxicity for host cells was not observed at this concentration. A synergistic effect (combination indices < 0.5) was demonstrated in vitro following 48 h of treatment with the combination of gatifloxacin and pyrimethamine (1:1 ratio). Doses of gatifloxacin of 100 and 200 mg/kg of body weight/day administered orally to mice for 10 days resulted in significant (P values of 0.056 and <0.0001, respectively) prolongation in time to death following infection with a lethal inoculum of tachyzoites. A dose of 400 mg/kg resulted in 20% survival (P = 0.0001). Mortality was 100% in untreated control mice and in mice treated with 25 or 50 mg/kg/day. Treatment of infected mice with a combination of gatifloxacin at 200 mg/kg/day and pyrimethamine at 12.5 mg/kg/day resulted in 85% survival, whereas 100 and 80% of mice treated with gatifloxacin alone or pyrimethamine alone, respectively, died (P < 0.0001). Moreover, a gatifloxacin dose of 200 mg/kg/day administered orally for 10 days plus 2 microg of recombinant murine IFN-gamma/day administered intraperitoneally for 10 days resulted in significant survival compared with IFN-gamma alone (P < 0.0001) or gatifloxacin alone (P < 0.007).

Seroepidemiology of varicella-zoster in Pakistan

The availability of safe and effective vaccines has renewed interest in the epidemiology of varicella worldwide. To date published data on the epidemiology of varicella in Pakistan is very scarce. Therefore, we conducted a study to determine the age-specific seroprevalence rate of varicella-zoster virus (VZV) antibodies in Pakistan. Between December 1997 and March 1998, 1,509 healthy volunteers aged between 1 month and 30 years were recruited from the Islamabad, Karachi, Lahore and Rawalpindi areas. Demographic information, socioeconomic status and past medical history were obtained by questionnaire. Serum samples were assayed for IgG antibodies against VZV by enzyme-linked immunosorbent assay. Overall 41.8% (600/1,435) of those tested were found to be seropositive for VZV antibodies. No difference was found in results obtained from the different cities. A higher seroprevalence was observed among women (45.2%) compared to men (39.6%). Seroprevalence rates increased with age and were 28.4% in those aged 0-5 years, 41.5% in the 6-10 year age group, 42.5% in the 11-15 year age group, 46.7% in the 16-20 year age group and 53.6% in those aged 21-30 years. Socioeconomic status was not a significant risk factor for VZV seropositivity. This is the first report of the seroepidemiology of VZV in Pakistan. The results indicate that seroprevalence of VZV increases with age in the Pakistani population studied. As in other tropical countries, there is greater susceptibility to varicella among the adolescent and young adult population. The results of this study suggest that these at-risk groups should be included in vaccination programs aimed at reducing the public health impact of varicella.

Dynamical quark effects on light quark masses

Light quark masses are calculated in lattice QCD with two degenerate flavors of dynamical quarks. The calculations are made with improved actions with lattice spacing a = 0.22-0.11 fm. In the continuum limit we find m(M&Smacr;)(ud)(2 GeV) = 3.44(+0.14)(-0.22) MeV using the pi and rho meson masses as physical input, and m(M&Smacr;)(s)(2 GeV) = 88(+4)(-6) MeV or 90(+5)(-11) MeV with the K or straight phi meson mass as additional input. The quoted errors represent statistical and systematic combined, the latter including those from continuum and chiral extrapolations, and from renormalization factors. Compared to quenched results, two flavors of dynamical quarks reduce quark masses by about 25%.

L-carnitine moderately improves the exercise tolerance in chronic stable angina

OBJECTIVES

To study the safety and efficacy (with reference to exercise ECG testing) of oral L-carnitine in chronic stable angina.

METHODS

Forty-seven patients, 30 men and 17 women, aged 56 +/- 8 years, were randomized to receive L-carnitine (n = 28) or placebo (n = 19) in the dose of 2 g/day for 3 months. The adjuvant treatment was not changed during the study. Patients were evaluated by computerized stress test (CST) done at the beginning and end of the trial. The parameters assessed were exercise duration, time to onset of ST changes, total ST score at peak exercise, rate-pressure product at peak exercise, and time needed for the ST changes to recover to baseline.

RESULTS

The two groups were comparable at the beginning of the study. There was no change in the CST parameters in the placebo group at the end of 3 months. In the L-carnitine group there was a statistically significant improvement in the exercise duration from 7.8 +/- 2.2 min to 8.6 +/- 1.8 min (p = 0.006) and in the time needed for the ST changes to revert to baseline from 7.2 +/- 3.9 min to 5.7 +/- 3.8 min (p = 0.019). No change was noted in the time to onset for ST depression, ST score and double product. There were no systemic adverse effects or coronary events in either group.

CONCLUSION

Oral L-carnitine is safe and moderately improves the duration of exercise and time to recovery of ST changes in patients with chronic stable angina.

Structural changes in the tunica intima of varicose veins: a histopathological and ultrastructural study

Many factors have been implicated in the aetiology of varicose veins; however, there is ample evidence implicating that the defect is in the wall of the lower limb veins. In order to know the pathological changes in the tunica intima of varicose veins, the smooth muscle cells (SMCs), collagen and elastin of varicose and control patients were studied by light and electron microscopy. The morphological changes in the SMCs, collagen and elastin point to a possible secretory or phagocytic role of the SMCs in producing abnormal immature collagen or elastin fibres or in modulation of function of SMCs due to excessive production of extracellular matrix (ECM).

Distribution of HLA-DQA1, polymarker, CSF1PO, vWA, TH01, TPOX, D16S539, D7S820, D13S317, and D5S818 alleles in East Bengali and West Punjabi populations from Indo-Pak Subcontinent

Blood samples were collected from 115 individuals residing in the Pakistani state of West Punjab and 81 Bengali individuals residing in the state of East Bengal, India. These samples were analyzed for the loci HLA-DQA1, PM (LDLR, GYPA, HBGG, D7S8, and GC) and eight short tandem repeats: CSF1PO, TPOX, THO1, vWA, D16S539, D7S820, D13S317, and D5S818. Departures from Hardy-Weinberg (HWE) were observed in Punjabi population at LDLR, THO1, D13S317, D5S818, and D16S539 and at CSF1PO and THO1 in Bengali population.

Protection against lipopolysaccharide-induced death by fluoroquinolones

Because fluoroquinolones have an immunomodulatory effect on cytokine production by lipopolysaccharide (LPS)-treated human monocytes, we examined the effect of fluoroquinolones on the survival of mice injected with a lethal dose of LPS. Trovafloxacin (100 mg/kg), ciprofloxacin (250 mg/kg), and tosufloxacin (100 mg/kg) protected 75% (P = 0.0001), 25% (P = 0.002), and 50% (P = 0.002), respectively, of mice against death. The fluoroquinolones significantly reduced serum levels of interleukin-6 and tumor necrosis factor alpha in LPS-treated mice. The protective effects of fluoroquinolones in LPS-induced shock in mice may also occur in humans.

Cloning, expression, and characterization of the katG gene, encoding catalase-peroxidase, from the polycyclic aromatic hydrocarbon-degrading bacterium Mycobacterium sp. strain PYR-1

A 81-kDa protein from Mycobacterium sp. strain PYR-1 was expressed in response to exposure of the strain to the polycyclic aromatic hydrocarbon pyrene and recovered by two-dimensional gel electrophoresis. The N-terminal sequence of the protein indicated that it was similar to catalase-peroxidase. An oligonucleotide probe designed from this sequence was used to screen a genomic library of Mycobacterium sp. strain PYR-1, and a positive clone, containing a part of the gene encoding the 81-kDa protein, was isolated. A gene-walking technique was used to sequence the entire gene, which was identified as katG for catalase-peroxidase. The deduced KatG protein sequence showed significant homology to KatGII of Mycobacterium fortuitum and clustered with catalase-peroxidase proteins from other Mycobacterium species in a phylogenetic tree. The katG gene was expressed in Escherichia coli to produce a protein with catalase-peroxidase activity. Since the induction of this catalase-peroxidase occurred in pyrene-induced cultures and the exposure of these cultures to hydrogen peroxide reduced pyrene metabolism, our data suggest that this enzyme plays a role in polycyclic aromatic hydrocarbon metabolism by strain PYR-1.

Comparative molecular analysis of erythromycin-resistance determinants in staphylococcal isolates of poultry and human origin

The ermA, ermB, ermC and msrA/msrB genes were detected in multidrug-resistant Staphylococcus spp. strains by PCR. Among 25 human clinical staphylococcal isolates the ermA, ermB, ermC and the msrA/msrB genes were detected in 88, 72, 4 and 100% of the strains, respectively. Among 24 poultry isolates the ermA, ermB, ermC and the msrA/msrB genes were detected in 100, 16.6, 50 and 12.5% of the strains, respectively. The ermA gene was found exclusively on the chromosome, whereas the ermC gene was found on 2.4-4.2 kb plasmids. Restriction fragment length polymorphism (RFLP) analysis of the ermA gene with Eco RI revealed five patterns (25.0, 21.0, 10.5, 6.2 and 4. 8 kb) for the clinical strains and two (8.0 and 6.2 kb) for the poultry strains. The 6.2 kb RFLP pattern, in both the poultry and human clinical isolates, indicates a common lineage for the ermA gene.

Characterization of erythromycin-resistant methylase genes from multiple antibiotic resistant Staphylococcus spp isolated from milk samples of lactating cows

OBJECTIVE

To isolate and characterize erythromycin-resistant methylase genes in multiple-antibiotic resistant staphylococci isolated from milk samples.

ANIMALS

300 lactating cows.

PROCEDURE

23 erythromycin-resistant staphylococci were isolated from milk samples of 300 lactating cows. The prevalence of erythromycin-resistant methylase (erm) genes, ermC and ermA genes, and the multicomponent macrolide efflux pump in staphylococci msrA genes were identified and characterized by use of multiplex polymerase chain reaction (PCR), Southern hybridization, restricted fragment length polymorphism (RFLP) analysis, and dot-blot hybridization.

RESULTS

Biochemical characterization indicated that 3 of 23 (13%) isolates were coagulase-positive Staphylococcus aureus, and the rest were coagulase-negative. Multiplex PCR resulted in amplification of a 520-base pair (bp) region of the ermC gene from the cell lysates of a strain of S simulans M-21 and S sciuri M-28. The ermC gene in both isolates was found on a 3-kilobase plasmid. The ermA gene was found on the chromosome of 21 isolates, and 6 RFLP patterns were observed. None of the isolates harbored the msrA gene.

CONCLUSIONS

Erythromycin-resistant Staphylococcus spp isolated from milk samples of lactating cows may serve as reservoirs of erm genes homologous to those described in human isolates. However, the chromosomal insert patterns and prevalence of these genes, the sizes of plasmids harboring the genes, and the number of inserts of the genes (copy number) may differ from that of human isolates.

Ketolide ABT-773 is active against Toxoplasma gondii

ABT-773 is active in vitro and in vivo against Toxoplasma gondii. It inhibited replication of RH strain tachyzoites in human foreskin fibroblasts. Mice infected intraperitoneally with tachyzoites and treated orally with 25, 50 or 100 mg/kg/day of ABT-773 for 10 days had 20% (P: = 0.016), 50% (P: = 0.003) and 100% (P: = 0.001) survival, respectively. Remarkable and highly significant survival was also noted in mice infected orally with strain C56 cysts and treated with ABT-773. Thus, ABT-773 may be useful for therapy of human toxoplasmosis.

Cloning, sequencing, and expression in Escherichia coli of a cytochrome P450 gene from Cunninghamella elegans

A polyclonal antibody against microsomes of a fungus, Cunninghamella elegans, was used to screen a C. elegans cDNA library. A cDNA clone, containing an open reading frame (ORF) encoding a protein of 389 amino acids (aa), was obtained. GenBank comparison (BLAST) showed that the protein was closely related to P450 because a heme-binding region, which is highly conserved in all P450 sequences, was found in the ORF protein. Using an oligo probe designed from this C. elegans heme-binding region to rescreen the cDNA library, we obtained three new clones. Sequence comparison showed that the three clones, with different length cDNA inserts, were from the same mRNA of the C. elegans P450 gene. One clone had the full C. elegans P450 gene, encoding 473 aa with a molecular mass of 54958.60, whereas the 389 was a part of the 473 aa without the N-terminal. The entire C. elegans P450 gene was successfully subcloned and overexpressed in a plasmid-Escherichia coli system (pQE30). Immunostaining with three antibodies (CYP1A1, CYP2E1, and CYP3A1) against mammalian P450 enzymes and benzidine staining for hemoproteins showed positive results for the recombinant protein expressed in E. coli. A phylogenetic tree was constructed by comparison of other fungal P450s to the C. elegans sequence. The C. elegans P450 clustered close to the cyp51 family and was named cyp509A1 by the International Committee on the Nomenclature for Cytochrome P450 Enzymes.