Genetic variations among the isolates of Bipolaris Maydis based on phenotypic and molecular markers

Abstract Maydis leaf blight, caused by Bipolaris maydis, is an important disease of maize crop in Khyber Pakhtunkhwa (KP) Pakistan. Fifteen isolates of the pathogen, collected across KP, were studied for variability based on phenotypic and molecular markers. Significant variability among the isolates was observed when assessed using phenotypic traits such as radial growth, spore concentration, fungicide sensitivity and virulence. The isolates were classified into six culture groups based on colour, texture and margins of the colony. Conidial morphology was also variable. These were either straight or slightly curved and light to dark brown in colour. Fungicide test showed significant variation in the degree of sensitivity against Carbendazim. Isolate Bm8 exhibited maximum radial growth on carbendazim spiked plates. Conversely, isolate Bm15 showed the lowest radial growth. Variations in virulence pattern of the isolates were evident when a susceptible maize variety Azam was inoculated with spores of B. maydis. Genetic variability amongst the isolates was also estimated by RAPD as well as sequencing of ITS region. The RAPD dendrogram grouped all the isolates into two major clusters. Average genetic distance ranged from 0.6% to 100%, indicating a diverse genetic gap among the isolates. Maximum genetic distance was found between isolates Bm9 and Bm10 as well as Bm2 and Bm8. Conversely, isolates Bm13 and Bm15 were at minimum genetic distance. Phylogenetic dendrogram based on sequencing of ITS region grouped all the isolates into a single major cluster. The clusters in both the dendrogram neither correlate to the geographical distribution nor to the morphological characteristics.

Resumo A ferrugem das folhas de maydis, causada por Bipolaris maydis, é uma doença importante da cultura do milho em Khyber Pakhtunkhwa (KP), Paquistão. Quinze isolados do patógeno, coletados em KP, foram estudados quanto à variabilidade com base em marcadores fenotípicos e moleculares. Variabilidade significativa entre os isolados foi observada quando avaliada por meio de características fenotípicas, como crescimento radial, concentração de esporos, sensibilidade a fungicida e virulência. Os isolados foram classificados em seis grupos de cultura com base na cor, textura e margens da colônia. A morfologia dos conídios também foi variável. Estes eram retos ou ligeiramente curvos e de cor marrom-claro a escuro. O teste de fungicida mostrou variação significativa no grau de sensibilidade ao carbendazim. O isolado Bm8 exibiu crescimento radial máximo em placas com adição de carbendazim. Por outro lado, o isolado Bm15 apresentou o menor crescimento radial. As variações no padrão de virulência dos isolados foram evidentes quando uma variedade de milho suscetível Azam foi inoculada com esporos de B. maydis. A variabilidade genética entre os isolados também foi estimada por RAPD, bem como sequenciamento da região ITS. O dendrograma RAPD agrupou todos os isolados em dois grupos principais. A distância genética média variou de 0,6% a 100%, indicando uma lacuna genética diversa entre os isolados. A distância genética máxima foi encontrada entre os isolados Bm9 e Bm10 e também entre Bm2 e Bm8. Por outro lado, os isolados Bm13 e Bm15 estavam a uma distância genética mínima. O dendrograma filogenético baseado no sequenciamento da região ITS agrupou todos os isolados em um único aglomerado principal. Os agrupamentos em ambos os dendrogramas não se correlacionam com a distribuição geográfica nem com as características morfológicas.

Cardiac, pulmonary and other body changes in children with gaucher disease during therapy

Gaucher disease is a multisystemic lipidosis characterized by hematologic problems, organomegally, skeletal involvement with or without neurological affection. The aim of the study is to identify the multisystemic involvements in children with Gaucher disease and to evaluate the effect of enzyme replacement therapy [ERT] on such patients. This study included 40 patients with Gaucher disease attending the Hematology Unit, Pediatric University Hospital during the period from January to December 2012. All cases were subjected to full history taking, thorough clinical examination, complete blood count, abdominal ultrasonography, radiological examination of the chest, distal end of femur and proximal end of tibia, EEC, echocardiography, Doppler echocardiography, tissue Doppler echocardiography and High Resolution C.T chest [HRCT]. Results: Significant differences were detected between cases and controls in weight, height and skull circumference [p value < 0,001]. Patients during ERT showed a significant decrease in frequency of epistaxis and blood transfusion than those before ERT [p value < 0.05]. Patients during ERT showed a significant increase in mean Hb level and platelet count than those before ERT [p value < 0.05]. There were no significant differences between the two groups of patients regarding the radiological bone changes and neurological aspects of Gaucher disease. Conclusion: Gaucher disease must be suspected in any child with organomegally, bone problems, bleeding tendency with or without neurological affection. ERT is effective in the management of hematological and visceral aspects of Gaucher disease. ERT has no role in the neurological aspect of Gaucher disease

Effects of alpha-1 adrenergic receptor antagonist, terazosin, on cardiovascular functions in anaesthetised dogs.

Initially a dose-response curve of phenylephrine was constructed at dose strengths of 1-16 microg/kg in a cumulative manner. Phenylephrine caused a significant rise in the mean arterial pressure, left ventricular systolic pressure, left ventricular contractility, stroke volume and a significant decline in the heart rate. Terazosin was administered in three selected doses of 10, 100 and 300 microg/kg. Following each dose of terazosin, dose-response curve of phenylephrine was constructed. Terazosin, per se, decreased the basal mean arterial pressure, left ventricular systolic pressure, left ventricular contractility and stroke volume significantly in a dose dependent manner with an increase in the heart rate with no significant change in the cardiac output. The baroreflex sensitivity at all the three doses remained unchanged. In conclusion, the present findings support the view that terazosin reduces the blood pressure in a physiologically more favorable manner by maintaining the neural integrity of the cardiovascular system.

Baroreceptor mediated blood pressure regulation is not affected during dose dependent inhibition of prostatic contractions by terazosin.

Benign prostatic hyperplasia (BPH), common in aging males is often treated with alpha1-adrenoceptor (AR) antagonists. In view of known hypotensive effect of most of the alpha1-AR antagonists, this work examined the effect of a selected alpha1-AR antagonist, terazosin on the baroreceptor mediated regulation of blood pressure. The three doses of terazosin (10, 100, 300 microg/kg body weight) used in anesthetized dogs inhibited in a dose-dependent manner the prostatic contractions and rise in blood pressure induced by phenylphrine. Impairment of arterial baroreflex, an important neural regulatory mechanism for the maintenance of normal arterial pressure, by alpha1-AR antagonist (prazosin) has been suggested in an earlier study. Hence, the effects of terazosin in doses 10, 100 and 300 microg/kg on baroreflex sensitivity (calculated as the ratio of heart rate change to acute increase in blood pressure by phenylephrine) were investigated. Terazocin did not produce any change in the baroreflex sensitivity. Therefore, in the absence of any adverse effect on the baroreceptor mediated regulation of the blood pressure, terazosin can be treated as a safer drug for the symptomatic treatment of BPH.

Influence of influenza viral infection on airway smooth muscle activity.

The contractility of airway smooth muscle (ASM) plays an important role in pathophysiology of several bronchial disorders. Increased contraction of ASM during asthma and respiratory viral infection has been attributed to the release of mediators acting through different receptors. In the present study, influence of influenza type A virus (H1N1) infection has been examined on ASM responsiveness to various bronchoactive agents e.g. adenosine, histamine, 5-hydroxytryptamine (5-HT) and isoproterenol in an organ bath set up for isolated tissue preparation. The contractile effect of adenosine, histamine and 5-HT was enhanced, however, relaxant response of isoproterenol was attenuated with the duration following viral exposure. The most prominent response was observed 48 to 72 hr after infection and tissues from multiple exposure to virus infected animals showed the maximum contractile response. Results demonstrated the deleterious effect of viral infection on ASM function and the findings will be helpful in understanding the mechanism of influenza virus induced bronchoconstriction.

Serum atrial natriuretic peptide, lipid profile and lipid peroxidation in adriamycin therapy of leukemia and lymphoma

Serum atrial natriuretic peptide [ANP], triglycerides, cholesterol and lipid peroxides were studied in thirty-one cases of acute lymphoblastic leukemia [ALL] [including fifteen newly diagnosed cases and sixteen relapses cases], twenty-nine cases of non-Hodgkin's lymphoma [NHL] comprised fifteen newly diagnosed cases and fourteen relapsed cases, ten oncogenic controls and ten healthy controls. Adriamycin was included in therapy of studied cases and not in that of oncogenic controls. Beside full clinical examination and routine investigations to diagnose ALL and NHL cases, ECG and echocardiography were done to all cases and controls. Serum ANP, triglyceride, cholesterol and lipid peroxides were measured before adriamycin therapy, three weeks after the first remission, three weeks after the second remission and in serum of the control group. It was concluded that serum ANP in patients treated with adriamycin is helpful diagnostic tool for early detection of myocardial damage and early management even in the absence of echocardiographic changes as the rise in ANP level is related to the drug dose and not related to the malignancy itself. Serial determinations of serum triglyceride, cholesterol and lipid peroxides are helpful for early detection and prevention of myocardial damage

Hypotensive effect of intracerebroventricular injection of norepinephrine and its modulation by alpha and beta adrenergic blockers in conscious rabbits.

The present study was designed to investigate the role of central adrenoceptors in the hypotensive effect of intracerebroventricular (ICV) injection of norepinephrine (NE) in conscious rabbits. Experiments were carried out on 19 adult rabbits (oryctolagus cuniculus) of either sex. A dose-dependent hypotensive response to ICV injection of NE was observed with no significant change in heart rate. The hypotensive response of NE was blocked 74.2 +/- 0.7% by yohimbine (alpha-2 adrenergic blocker), and 25.0 +/- 0.5% by metoprolol (beta-1 adrenergic blocker). NE response was not affected either by prazosin or butoxamine (alpha-1 and beta-2 adrenergic blockers respectively). The results suggest that the dose-dependent hypotensive response of ICV administered NE is mediated through alpha-2 and beta-1 central adrenoceptors.

Effect of acute haemodilution on right atrial type-B receptor activity in anaesthetized cats.

In order to investigate whether the sensitivity of atrial type-B receptors to its natural stimulus is altered during acute haemodilution, experiments were conducted in nine anaesthetized, artificially ventilated and thoracotomized cats. Haemodilution was achieved by replacement of blood by the same volume of dextran (MW 150000). Atrial receptor activity, arterial blood pressure, right atrial pressure and ECG were recorded. Heart rate was calculated from ECG records. Arterial blood hematocrit was measured. Mean arterial blood pressure and heart rate were not altered by haemodilution even at a hematocrit level of 12.17 +/- 0.93 percent. Average activity of type-B atrial receptors, mean right atrial pressure, right atrial peak 'v' pressure, right atrial initial 'v' pressure and right atrial 'v' wave amplitude were changed significantly (r < 0.05) during acute haemodilution when the hematocrit was 12.17 +/- 0.93 percent but the atrial type-B receptor activity per cycle did not show any significant change. Average activity of type-B receptors increased from 8.56 +/- 1.02 spikes/sec to 9.56 +/- 1.11 spikes/sec. Mean right atrial pressure, right atrial 'v' wave amplitude, right atrial peak 'v' pressure increased significantly (P < 0.05) from respective control values. Right atrial initial 'v' wave pressure decreased significantly. Heart rate changed from 168.11 +/- 5.42 beats/min to 170.89 +/- 5.65 beats/min. Mean arterial pressure changed from 134.33 +/- 0.89 mmHg to 135.67 +/- 1.46 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular responses to phenylephrine during acute experimental anaemia in anaesthetized cats.

Experiments were performed on anaesthetized artificially ventilated cats to study the effects of phenylephrine (PE) on cardiovascular responsiveness, before and after induction of experimental anaemia. Acute anaemia was induced by replacement of blood by dextran in three steps of 20% each of total estimated blood volume. The effect of PE (20 micrograms/kg) was investigated at four stages: control and after 1st, 2nd and 3rd exchanges of blood. Induction of anaemia produced a significant increase in heart rate (HR) and cardiac output (CO) and a decrease in right atrial pressure (RAP). No significant change in mean arterial pressure (MAP), LV dP/dt max and blood gas tension was observed. Administration of bolus dose of PE produced a rapid rise in MAP, LVdP/dt max, and a decrease in HR without a change in the RAP. The pattern of response to PE was similar after induction of acute anaemia, however the magnitude of the response was significantly reduced. The attenuation in the response to PE was related to the fall in the haematocrit (HCT) level. This shows that induction of experimental anaemia, produced an increase in CO due to an increase in HR and SV and the effect of PE on cardiovascular responsiveness was significantly attenuated. The reduced sensitivity to PE during acute anaemia could be due to many factors such as inadequate O2 supply, effect of local vasodilating agents or some other cardiotonic agents which are known to contribute to vascular responsiveness.

Effect of Ajmaloon on the baroreceptor-heart rate reflex in anaesthetized rabbits and monkeys.

The effects of a herbal drug, Ajmaloon (Hamdard, India), on the arterial blood pressure, heart rate (HR) and baroreceptor-heart rate reflex were studied in anesthetized rabbits and monkeys. Intravenously administered Ajmaloon produced a dose-dependent hypotensive response in both the species without any significant effect on the heart rate. Only in high doses (200 mg/kg or more). Ajmaloon produced a bradycardia response in rabbits. Even the highest dose (300 mg/kg) of Ajmaloon used in the present investigation did not cause arrhythmia or any other conduction disorder or respiratory distress. Baroreflex SAP-HR curve was shifted to the left of the control following treatment with 100 mg/kg intravenous Ajmaloon in both the species. Loss of tachycardia response to fall in arterial pressure in Ajmaloon treated animals indicated the drug induced suppression of normally existing sympathetic excitatory influence in response to hypotension. Baroreflex regulatory HR response to hypertension remains intact after intravenous administration of 100 mg/kg Ajmaloon, a dose much higher than the prescribed highest oral dose for humans. Intact baroreflex regulation of arterial blood pressure in response to hypertension in Ajmaloon treated mammals suggests that in patients besides lowering the blood pressure. Ajmaloon might not interfere with the normal blood pressure regulatory mechanism through arterial baroreceptors during hypertension.

Cardiovascular responses to phenylephrine and sodium nitroprusside during acute coronary occlusion in dogs.

The effects of administration of pressor agent phenylephrine (PE) and depressor agent, sodium nitroprusside (SNP) (10-40 micrograms/kg) on arterial blood pressure (ABP) and heart rate (HR) were investigated during acute occlusion of left anterior descending coronary artery (LAD) in anaesthetized, artificially ventilated dogs with and without the influence of selective blockade of autonomic nervous system (ANS). ABP response to PE was significantly (P < 0.05) attenuated following 4 hrs of LAD occlusion in all the four groups of animals. SNP response at higher dose (40 micrograms/kg) was also significantly (P < 0.05) attenuated 4 hrs after LAD occlusion in ANS intact, beta-blocked and atropinized groups. The bradycardia response to PE after LAD occlusion was abolished in vagotomized group while in the other three groups, it was significantly attenuated following 4 hrs of LAD occlusion. The tachycardia response to SNP was significantly (P < 0.05) attenuated 4 hrs after LAD occlusion in ANS intact and atropinized animals. The response was abolished in beta-blocked animals and no significant change occurred (P > 0.05) in vagotomized group. This study suggests that the cardiovascular reflex effects of PE and SNP are significantly attenuated following acute LAD occlusion. Blocking any of the components of ANS changed this responsiveness.

Effect of acute haemodilution on right atrial type-A receptor activity and right atrial pressure in anaesthetized cats.

To determine the effects of acute haemodilution on right atrial pressure and right atrial type-A receptor activity, experiments were conducted in nine anaesthetized cats. Haemodilution was induced by replacement of blood by same volume of dextran (molecular weight-150000). Arterial blood pressure, right atrial pressure and right atrial type-A receptor activity were recorded. Hematocrit, arterial blood pO2, pCO2, and pH were measured. Mean arterial blood pressure, pO2, pCO2, and pH were not altered by haemodilution which extended to a hematocrit level of about 13%. Mean right atrial pressure, 'a' wave pressure showed significant changes after 2nd and 3rd exchange. Heart rate and 'a' wave amplitude changed significantly (P < 0.05) after 3rd exchange. The amplitude of the 'a' wave was increased from 3.57 +/- 0.93 to 5.79 +/- 1.46 cm H2O, heart rate was increased from 163.89 +/- 5.36 to 169.22 +/- 4.84 beats/min, mean right atrial pressure was increased from 2.85 +/- 0.31 to 4.61 +/- 0.27 cm H2O, initial 'a' wave pressure was increased from 1.78 +/- 0.09 to 5.06 +/- 0.44 cm H2O. The data indicate that under present experimental conditions, the activity of the type-A receptor did not show any significant change (P > 0.05) on acute haemodilution. Significant increase (P < 0.05) in the amplitude of 'a' wave, mean right atrial pressure and initial 'a' wave pressure could be attributed to increased myocardial contractility.