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.

Comparison of geometric design of a brand of stainless steel k-files: an in vitro study

The purpose of this experimental study was to determine the diametric variations of a brand of handheld stainless-steel K-files, acquired from different countries, in accordance with the available standards. 20 Mani stainless-steel K-files of identical size [ISO#25] were acquired from Pakistan and were designated as Group A while 20 Mani K-files were purchased from London, UK and designated as Group B. Files were assessed using profile projector Nikon B 24V. Data was statistically compared with ISO 3630:1 and ADA 101 by one sample T test. Significant difference was found between Groups A and B. Average discrepancy of Group A fell within the tolerance limit while that of Group B exceeded the limit. Findings in this study call attention towards adherence to the dimensional standards of stainless-steel endodontic files

Determination of fracture patterns of a brand of stainless steel K files; an in vitro study

Objective of the study was to qualitatively determine and compare the fracture patterns of hand held stainless steel K files [Mani, Inc. Japan], acquired from Pakistan and United Kingdom. This study was conducted at the Institute of Space Technology, over a period of one month. A total of 40 stainless-steel K files [Mani, Inc. Japan] of identical size [ISO#25] were collected and divided into two groups, such that Group A consisted of 20 K files acquired from the Rawalpindi/ Islamabad region in Pakistan while Group B consisted of 20 K files that were purchased from London, UK. The files were fractured one by one, 3mm from the tip. The fractured surfaces were then observed under scanning electron microscope to determine their fracture patterns. Evaluation of the fractured surfaces revealed decreased ductility in Group A in comparison with Group B. Stainless steel endodontic files available commercially in Pakistan need evaluation of their fracture behavior for patient safety and benefit

unusual presentation of foreign body oesophagus

A case of long standing oesophageal foreign body [coin] in a child is discussed. The patient was unusual in several respects, especially the way it presented: failure to thrive secondary to the under nourishment caused by the foreign body. The foreign body was diagnosed only after it had eroded the walls of the oesophagus and the right main bronchus producing a bronchooesophageal fistula

Management of tracheobronchial foreign bodies in children

A study of 52 cases of foreign body tracheobronchial tree in children over a year period has been conducted. More than 70% of patients were aged 2 years and below. The male to female ratio was about 3:1. More than 80% of foreign bodies were vegetable in nature and the commonest site was the right main bronchus. In all cases, foreign bodies were removed under G.A., with the help of rigid paediatric bronchoscopes. There was no mortality. The availability of skilled anaesthetists and venturi system of ventilation was invaluable. In the majority of patients, a history of foreign body inhalation was available but in four cases no such history was forthcoming and bronchoscopy was done to exclude a foreign body because the child had persistent cough and episodes of dyspnoea. There was a delay of 1-5 days before presentation in the majority of the patients