A multiplex PCR for Massachusetts and Arkansas serotypes of infectious bronchitis virus

Infectious bronchitis virus (IBV), the prototype of the coronavirus family, is an enveloped, single-stranded RNA virus with a genome size of approximately 27.6 kilobase. Infectious bronchitis virus causes an acute, highly contagious respiratory and urogenital disease of chickens which results in significant economic losses in commercial broilers, layers and breeders. A rapid, highly sensitive and specific method is needed in the differential diagnosis of infections of different serotypes. A multiplex polymerase chain reaction (PCR) method was developed and optimized to simultaneously detect Massachusetts (Mass) and Arkansas (Ark) serotypes of IBV. One common primer and two serotype specific primers were chosen from the S1 gene sequences of IBV and used in one PCR reaction. Under optimized PCR conditions, two serotype specific PCR products, 1026 bp for Mass and 896 bp for Ark, respectively, were amplified and detected by agarose gel electrophoreses. The specificity of the technique was verified by using 20 different strains and isolates of IBV, and other avian bacterial and viral pathogens. Using a serial 10-fold dilution of the artificial mixture of both Mass and Ark samples, the detection limit was found to be 5 pg RNA after 35 cycles of PCR. The multiplex PCR was able to detect and differentiate both serotypes in embryonated eggs that were co-infected with different EID50virus titers of Mass 41 and Ark 99. The multiplex PCR developed in this study will be valuable for rapid identification, differential diagnosis, and epidemiological studies of these two serotypes of IBV infections.

Detection of avian adenovirus by polymerase chain reaction

An avian adenovirus-specific polymerase chain reaction was developed. The origin of primers was from the DNA sequence data of the chicken embryo lethal orphan avian adenovirus virus genome. An avian adenovirus-specific 421-bp DNA product was amplified by these primers from group I of adenovirus containing 12 serotypes and serotypes of adenovirus from group II and group III. The adenovirus-specific DNA product was also amplified from the 19 field isolates of avian adenoviruses but not from the mammalian adenovirus and other avian pathogenic viruses and bacteria. As little as 1 fg of avian adenovirus DNA was detected by gel electrophoresis and Southern blot analysis.

Cell death in the brain of the HTx rat

The structural changes in the hydrocephalic brain suggest that cell death must be a significant factor in the loss of cortical mantle thickness and cell numbers. In the developing hydrocephalic brain a similar conclusion might also be reached. We present data suggesting that in the developing hydrocephalic HTx rat brain, there are at least two processes that underlie the structural deficit in the cortex. The first is abnormal development of the cortex probably resulting from a combination of the genetic defect and blockage of CSF circulation in the fetus. The second is a direct consequence of raised intracranial pressure and is manifested in a lack of development of glial cells in the neonatal brain and in the loss of myelination and neurones as pressure rises after birth, particularly after skull plate fusion. We find little evidence of increased cell death by apoptosis, recording instead a decrease in apoptotic index. There is evidence that necrosis must have occurred.

Characterization of a novel exo-N-acetyl-beta-D-glucosaminidase from the thermotolerant Bacillus sp. NCIM 5120

An exo-N-acetyl-beta-d-glucosaminidase from the thermotolerant Bacillus sp. NCIM 5120 was purified to homogeneity by chromatography on CM-cellulose, Sephacryl S-300 and phenyl-Sepharose. The enzyme has a Mr of 230000 as determined by size exclusion chromatography on Sephacryl S-300/Sephadex G-200 and exhibited a relative subunit Mr of 60000 on denaturing gel electrophoresis. It is a neutral protein with a pI of 6.79. The optimum pH and temperature for the enzyme activity are 6.0 and 70 degreesC, respectively. Determination of the reaction stereochemistry indicates that the enzyme is a retaining glycosidase with the beta anomer of GlcNAc formed as the initial product. Determination of the energy of activation with different leaving groups (p-nitrophenol and 4-methyl-umbelliferone) reveals that the enzyme exhibits a biphasic Arrhenius plot with two characteristic energy of activation with an inflection temperature of 50 degreesC. The activation energy at temperatures below the inflection point was found to be higher than that above the inflection point. The energy of activation for 4-Me-Umb-beta-d-GlcNAc was higher at temperatures below the inflection point than for pNP-beta-d-GlcNAc (60.3 and 43.2 kJ mol-1, respectively). It hydrolyzes specifically, terminally linked beta(1-4) GlcNAc residues from the non-reducing end of oligosaccharides. Comparative studies on the hydrolysis of chito-oligosaccharides by the exo-N-acetyl-beta-d-glucosaminidase indicates that chitobiose is the best substrate with a Km and kcat of 0.34 mM and 24 microoff min-1mg-1, respectively. It also exhibits strict substrate specificity with respect to the glycone substitution as well as anomeric linkage.

Thermodynamics of ligand (substrate/end product) binding to endoxylanase from Chainia sp. (NCL-82-5-1): isothermal calorimetry and fluorescence titration studies

The binding of xylo-oligosaccharides to Chainia endoxylanase resulted in a decrease in fluorescence intensity of the enzyme with the formation of 1:1 complex. Equilibrium and thermodynamic parameters of ligand binding were determined by fluorescence titrations and titration calorimetry. The affinity of xylanase for the oligosaccharides increases in the order X2<X3<X4</=X5. Contributions from the enthalpy towards the free energy change decreased with increasing chain length from X2 to X4, whereas an increase in entropy was observed, the change in enthalpy and entropy of binding being compensatory. The entropically driven binding process suggested that hydrophobic interactions as well as hydrogen bonds play a predominant role in ligand binding.

Fluorimetric studies on saccharide binding to the basic lectin from Artocarpus hirsuta

The binding of Artocarpus hirsuta lectin to galactose and its derivatives was examined by fluorescence spectroscopy. The intrinsic fluorescence intensity of the lectin was enhanced by 55% upon binding to methyl alpha-galactose without any change in the emission maximum (333 nm). 4-Methyl umbellifery alpha-galactopyranoside showed 100% quenching of its fluorescence intensity upon binding to the lectin without any shift in the emission maximum (373 nm). The association constant for the binding of the above sugars to the lectin decreases with increasing temperature. Methyl group in the alpha anomeric position of galactose enhanced the binding while that in the beta position reduced the binding to the lectin. Solute quenching studies of the lectin using acrylamide, potassium iodide and cesium chloride indicated that the tryptophan residues were fully accessible to the neutral quencher, while only partly accessible to the ionic quenchers.

alpha-Galactoside binding lectin from Artocarpus hirsuta: characterization of the sugar specificity and binding site

The hemagglutinin from the seeds of Artocarpus hirsuta was purified to homogeneity by ion-exchange chromatography on DEAE-cellulose and CM-sephadex. The native protein of molecular mass 60,000 (gel filtration) is made up of two pairs of unidentical subunits, alpha and beta with molecular masses of 15,800 and 14,130. The lectin is basic in nature (pI 8.5) and a glycoprotein with neutral sugar content of 6.25%. Rabbit as well as human erythrocytes (A, B and O) are agglutinated by the lectin. The lectin activity is neither affected by Ca2+, Mg2+ or Mn2+ nor by EDTA. Methyl alpha-D-galactopyranoside, pNP-alpha-D-galactopyranoside and pNP-alpha-D-N-acetylgalactosamine are the best inhibitors of the lectin. 4-Methylumbelliferyl-alpha-galactopyranoside fluorescence was quenched on binding to A. hirsuta lectin. The sugar has two binding sites per tetramer of the lectin with a Ka of 3.5x105 M-1 at 25 degrees C. Chemical modification studies indicate that the net positive charge associated with epsilon-NH2 of lysine residues and the phenyl ring of tyrosine are essential for the sugar binding activity of A. hirsuta lectin.

Effect of the novel angiotensin II type 1 receptor antagonist L-158,809 on acute infarct expansion and acute anterior myocardial infarction in the dog

OBJECTIVES

To assess the effect of the angiotensin II type 1 receptor (AT1-R) antagonist L-158,809 on acute infarct expansion and left ventricular (LV) function during acute anterior myocardial infarction.

METHODS

Dogs were randomized to receive intravenous L-158,809 (0.1 mg/kg bolus and 0.6 microgram/kg/min infusion) or vehicle beginning 1 h after permanent left anterior descending coronary artery ligation and continued for 48 h. In vivo LV remodelling and function (quantitative echocardiography) and hemodynamics over 48 h, and postmortem remodelling after 48 h were measured.

RESULTS

L-158,809 produced 90% to 100% inhibition of the angiotensin II pressor response during the infusions. With respect to percentage changes over the 48 h in vivo, compared with vehicle controls, L-158,809 decreased mean arterial pressure (-20 +/- 4 versus -9 +/- 2%, P = 0.03) and left atrial pressure (-38 +/- 5 versus 25 +/- 6%, P < 0.0001) but did not change heart rate. These unloading effects were associated with a smaller percentage increase in infarct expansion index (-5 +/- 7% versus 27 +/- 2%, P = 0.001) and LV diastolic volume (11 +/- 11% versus 52 +/- 6%, P = 0.008), less shape deformation, fewer apical aneurysms (0 versus 100%, P = 0.0003), better global ejection fraction (49 +/- 2% versus 39 +/- 2%, P = 0.005), less ST segment elevation and fewer Q waves. Also compared with vehicle controls, with L-158,809 postmortem infarct size (19.8 +/- 2.4% versus 50.4 +/- 4.7% of risk region, P = 0.0002) and expansion index (2.06 +/- 0.09 versus 2.76 +/- 0.18, P = 0.006) were less and thinning ratio greater (0.92 +/- 0.02 versus 0.60 +/- 0.05, P = 0.0001).

CONCLUSIONS

The novel AT1-R antagonist L-158,809 produces significant AT1-R blockade, reduces LV loading, and effectively limits acute infarct expansion and early LV remodelling during canine myocardial infarction.

Effects of hydrocephalus on nitric oxide neurones in the brain of the HTx rat

The effect of hydrocephalus on the nitric oxide system in the brain of the HTx rat brain was investigated. We used NADPH-diaphorase histochemistry to stain neurones containing the enzyme, nitric oxide synthase. Comparison of normal and hydrocephalic HTx rat brains showed a reduction in stained neurones and a greatly depressed staining intensity in those that were labelled in the hydrocephalic brain. Also, there was an apparent reduction in number and length of radiating fibres from stained neurones. In addition to these changes we also observed a clear association between stained neurones and the microvasculature of the brain. This suggests that changes in the activity of these neurones may have a significant impact on the normal perfusion of the brain.

Changes in myocardial density during postinfarction healing: effect on estimation of in vivo left ventricular mass by echocardiographic imaging

To determine whether changes in density (rho) of infarct and noninfarct zones during healing and remodeling after myocardial infarction influence estimates of left ventricular mass and detection of temporal changes by imaging, we measured weights (g) and volumes (mL) of infarct, noninfarct, and mixed tissue in hearts removed 1 to 42 days after anterior infarction in three groups of dogs: nonreperfused infarction treated with placebo or captopril, or infarcts reperfused after 2 h. In vivo mass was calculated from in vivo diastolic myocardial volumes (echocardiograms) and an assumed density of 1.05 g/mL or actual values derived from tissue weights and volumes. Over the 42 days, actual density deviated more from the assumed value of 1.05 in infarct than noninfarct zones, and the overall density was higher for reperfused than nonreperfused ventricles (1.09 vs. 1.06 g/mL, p < 0.01). Correction for density improved the correlation between absolute in vivo and postmortem mass slightly but not the detection of relative changes in mass in control, captopril, or reperfusion groups. These findings suggest that (i) densities of infarct and noninfarct zones differ and change during healing, especially after reperfusion, and (ii) correction for density provides more accurate estimates of volume-derived mass in reperfused hearts.

Purification and characterization of an extracellular lectin (Lectin I) from Agrobacterium radiobacter NCIM 2443

A lectin from culture filtrate of Agrobacterium radiobacter NCIM 2443 is purified to homogeneity by ion exchange chromatography on a DEAE cellulose column followed by hydrophobic chromatography on phenyl sepharose and hydroxyapatite column chromatography. The protein (Lectin I) is a monomer of relative molecular mass 37,000, as determined by denaturing gel electrophoresis as well as size exclusion chromatography. Lectin I is stable at pH 5.0 and its isoelectric point is pH 4.0. Amino acid analysis reveals that acidic amino acids and glycine are predominant amino acids and cysteine is absent in the lectin. Chemical modification of tryptophan residues causes more than 80% loss of haemagglutination activity of the lectin and 60% loss of activity is caused by modification of carboxyl groups. Lectin I agglutinates rabbit erythrocytes but does not agglutinate human A, B and O types of erythrocytes. It is specific for N-acetyl D-glucosamine, chitobiose, pNP-beta-mannoside as well as high mannose type glycopeptides. The relative inhibition by disaccharides, oligosaccharides and glycoproteins indicates that Lectin I recognizes Man3-GlcNAc-GlcNAc core carbohydrate structure of asparagine linked glycopeptides. Tobacco tissue extracts also inhibit the haemagglutination activity of Lectin I.

Effect of angiotensin-converting enzyme inhibition on infarct collagen deposition and remodelling during healing after transmural canine myocardial infarction

BACKGROUND

Angiotensin-converting enzyme (ACE) inhibition for six weeks after myocardial infarction (MI) lowers the collagen content of infarct scars in dogs. However, temporal changes in collagen content of the infarct zone (IZ) with ACE inhibition during healing over six weeks after MI and their possible relation to IZ remodelling have not been determined.

METHODS

IZ collagen (hydroxyproline) was measured over six to seven weeks in dogs treated with captopril (50 mg bid), enalapril (2.5 mg bid) or placebo, beginning on the second day following transmural anterior MI (or sham). In vivo changes in IZ and global left ventricular (LV) remodelling, mass and function (echocardiograms) and hemodynamics among six-week survivors were also measured.

RESULTS

Compared with placebo, both inhibitors decreased IZ collagen (P < 0.001) over the seven weeks. Among the six-week survivors, both inhibitors lowered IZ collagen (P < or = 0.001) and increased the collagen type I:III ratio. However, preload was lower, increase in diastolic volume and mass were less and systolic function improved. Although the doses of captopril (but no enalapril) decreased afterload, inhibition of IZ collagen was less, IZ bulging and global LV dilation were less and systolic function was better with captopril than with enalapril. In all three MI groups, deaths over the seven weeks correlated with greater infarct size, LV volume and dysfunction and lower IZ collagen.

CONCLUSIONS

ACE inhibition suppresses the temporal increase in IZ collagen and attenuates IZ expansion, thinning and bulging, and LV enlargement and aneurysm formation during healing after MI.

Genotypic evaluation of Salmonella enteritidis isolates of known phage types by arbitrarily primed polymerase chain reaction

Salmonella enteritidis isolates of known phage types 8, 13a, and 14b were inoculated separately into a group of 14-wk-old specific-pathogen-free chickens. S. enteritidis isolates from pre- and postinoculum were analyzed with the use of arbitrarily primed polymerase chain reaction to determine any genotypic changes after reisolation from the chickens. The preinoculum isolates and the isolates of S. enteritidis recovered at 5, 10, 20, and 35 days postinoculation from the inoculated chickens with various phage types were similar. Therefore, no changes of S. enteritidis organisms of similar phage types occurred at the genotypic level. However, SE-3-B7001 (phage type 8) was changed to phage type 14b after inoculation into the chickens.

Amplification of avian reovirus RNA using the reverse transcriptase-polymerase chain reaction

A reverse transcriptase-polymerase chain reaction method was developed for the detection of avian reovirus. The origin of primers was from the S1 gene of the avian reovirus genome. A reovirus-specific 532-base pair cDNA product was amplified by these primers from six reference strains and 23 field isolates of avian reoviruses, but not from seven different avian pathogenic viruses and bacteria. As little as 1 pg of avian reovirus RNA was detected using gel electrophoresis and Southern blot hybridization.

Multiplex PCR for avian pathogenic mycoplasmas

Mycoplasma infections are of great concern in avian medicine, because they cause economic losses in commercial poultry production. A multiplex polymerase chain reaction (PCR) was optimized to simultaneously detect four pathogenic species of avian mycoplasmas. Four sets of oligonucleotide primers specific for Mycoplasma gallisepticum (MG), M. synoviae (MS), M. meleagridis (MM) and M. iowae (MI) were used in the test. By using agarose gel electrophoreses for detection of the PCR-amplified DNA products, the sensitivity of detection was between 1 pg for MG, 1 pg for MS, 100 fg for MM and 100 pg for MI after 35 cycles of PCR. Similar sensitivity of these primers was achieved with broth cultures of these four organisms.

Multiple intussusceptions in a juvenile rhea (Rhea americana) with proventricular impaction

Multiple intussusceptions of the small intestine were identified in a 4-mo-old rhea (Rhea americana) that died acutely after chronically poor growth. The chick was one of a group of 12 chicks that exhibited musculoskeletal deformities, poor growth, and subsequent death. Gross necropsy findings of this chick revealed proventricular impaction by sticks and stones accompanied by multiple intussusceptions of the small intestine. This finding identifies a disease process that may afflict ratites when raised for production and that may complicate treatment of proventricular impaction.

Rapid estimation of spoilage bacterial load in aerobically stored meat by a quantitative polymerase chain reaction

We report a quantitative PCR which utilizes primers from a conserved 23S rDNA sequence identified in nine different spoilage bacteria commonly present in meat. The PCR detected the spoilage bacteria by amplifying a specific 207 bp sequence from their chromosomal DNA. Quantification of PCR product by electrochemiluminescence revealed that the concentration of the amplified product was dependent on cycle number and the initial number of bacteria present in the sample. Statistical analysis of the results indicated a correlation coefficient of 0.94 (P < 0.001) between aerobic plate count and QPCR luminosity units.

Detection of Meat Spoilage Bacteria by Using the Polymerase Chain Reaction

The growth of spoilage bacteria results in a shorter shelf life of meat, causing economic losses to the meat industry. Based on 23S rDNA sequence data of Pseudomonas aeruginosa , two primers designated as PF (23 bases) and PR (20 bases) were synthesized for use in the polymerase chain reaction. A unique 207-base-pair DNA product from nine different bacteria typically associated with meat spoilage was amplified by the primers. Dot blot analysis with the internal DNA probe specific for the amplified products confirmed that the amplified DNA sequence is specific for the spoilage bacteria studied.

Endoscopic papillectomy: a novel approach to difficult cannulation

BACKGROUND

Selective cannulation of the biliary and pancreatic ducts is considered to be the most difficult and rate limiting aspect of diagnostic endoscopic retrograde cholangiopancreatography (ERCP).

AIMS/METHODS

A novel technique for difficult cannulation is described and its potential role in relieving malignant duodenal obstruction secondary to ampullary carcinoma. A diagnostic endoscopic papillectomy was performed in 10 patients in whom previous attempts at cannulation had failed. Five patients had exophytic ampullary carcinomas, one had carcinoma of the head of pancreas, two had an oedematous ampulla secondary to low common bile duct stones, while two had protuberant ampullae with ectopic orifices. The technique entails snaring the ampulla flush with the duodenal wall using a polypectomy snare and in a similar fashion to polypectomy removing the ensnared ampulla with diathermy using a coagulation current. The underlying exposed ducts can then be cannulated while the ensnared ampulla can be retrieved to aid histological diagnosis.

RESULTS

Successful cannulation was achieved in all 10 cases with significant haemorrhage in one patient (10%). Four of the snared ampullary carcinomas (80%) were retrieved enabling a histological diagnosis to be made.

CONCLUSIONS

This study demonstrates the potential role for endoscopic papillectomy as a means of cannulation in difficult circumstances, however larger comparative studies are required.