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[en] A faba bean rhizospheric Pseudomonas aeruginosa isolate RZ9 was used for studying its antifungal activity and protecting effects of faba bean and common bean against the root pathogen Fusarium culmorum strain MZB47. The dual culture tests showed that RZ9 inhibits MZB47 in vitro growth by 56%. When mixing RZ9 cell suspension with MZB47 macroconidia at equal proportion, the macroconidia viability was reduced with 70%. Pathogenicity tests conducted in sterile conditions showed that MZB47 caused an intense root rotting in faba bean ‘Aquadulce’ plantlets and a slight level in common bean ‘Coco blanc’. This was associated to significant decreases in plant growth only in ‘Aquadulce’, reducing shoot dry weight (DW) by 82% and root DW by 70%. In soil samples, MZB47 caused severe root rotting and induced significant decreases in shoot DW (up to 51%) and root DW (up to 60%) for both beans. It was associated to a decrease in nodule number by 73% and 52% for faba bean and common bean, respectively. Biocontrol assays revealed that the inoculation of RZ9 to MZB47-treated plantlets enhanced shoot DWs (25% and 110%) and root DWs (29% and 67%), in faba bean and common bean, respectively. Moreover, root rotting levels decreased and nodule number increased in treated compared to untreated plantlets. Collected data highlighted the disease severity of F. culmorum and demonstrated the potential of using RZ9 in controlling Fusaria root diseases in beans. Thereby, the current study represents the first report on the biocontrol effectiveness of P. aeruginosa against F. culmorum in beans
[en] Full text: The interest in Helicobacter pylori has not declined in these years. H. pylori causes a chronic gastric infection which is usually life-long and many epidemiological studies have shown that this is probably one of the most common bacterial infections throughout the world involving 30% of the population in developed countries and up to 70-90% of the population in developing regions. Thus, it is clear that the diagnosis of H. pylori infection represents at least a key step in the management of many of the patients referred to the gastroentelogist. Additionally, due to the wide range and relevance of pathologies possibly related to infection, including malignancies, there is the potential for H. pylori to be a major health problem. Improved methods for the diagnosis and follow up treatment of the infection have been developed in the last decades. The use of stable isotopes in non-invasive diagnostic methods, as the breath tests, was the key to a new era of research about H. pylori epidemiology, diagnostic, criteria for the eradication treatment, etc. This paper focuses on the different diagnostic methods employed, especially in those where isotopic techniques are applied. (author)
[en] Objective: To determine the frequency of fungal infection in nasal polyposis patients undergoing polypectomy in a tertiary care ENT unit. Methodology: This cross sectional study was conducted in the department of ENT, Pakistan Institute of Medical Sciences, Islamabad. A total of 60 patients with nasal polyposis were enrolled. Patients who did not give consent, with sinonasal malignancy, diabetes, and pregnant or lactating women were excluded from study. All the patients were operated and specimens of polypectomies were sent to the Department of Pathology for fungal culture, direct microscopy and histopathology. Data was entered and analysed using SPSS version 20. (author)
[en] In this study, three rhizobacterial strains were characterized by their ability to inhibit Rhizoctonia solani and tested in chili (Capsicum annuum L.) seedlings. Strains A46 and P61 were identified as Pseudomonas tolaasii, and S108 as Rhanella aquatilis. In the dual culture tests, all the strains inhibited the radial growth of R. solani. None of the three strains produced chitinases or volatile compounds, but they were found to produce siderophores. However, this last characteristic was not responsible for the rhizobacterial inhibitory effect on the growth of R. solani, other bacterial metabolites were possibly involved. The bacterial filtrates added to the potato dextrose agar medium (PDA) in a 3:7 ratio had significant antifungal activity, being the filtrate from strain S108 the one that showed the highest effect, with 56% fungal inhibition. The co-culture of strain A46 with the phytopathogenic fungi in potato dextrose broth (PDB) increased the antifungal activity of the rhizobacterial filtrate. The application of the rhizobacterial strains to Serrano chili decreased the R. solani-related mortality rate in seedlings; particularly, S108 had the greatest effect, which was similar to the fungicide effect. This study showed that the S108 strain has potential as a biofungicide to control R. solani in chili seedlings.
[en] Stem end rot majorly contribute in post-harvest losses of mango during storage. Maximum disease incidence (70%) was recorded in Sindhari cultivar followed by Chaunsa (64%), Fajri (62.5%) and 50% in both Langra and Anwar ratol. In vitro studies were carried out to identifyfungal pathogens responsible for rotting and decaying mango fruits during storage along with isolation and testing their pathogencity on healthy fruits. Results revealed that all selected commercial mango varieties infected by stem end rot. Colletotrichum gloeosporioides, Lasidodiplodia theobromae, Alternaria alternate, Aspergillus niger, Dothiorella domonicana were identified from Sindhri mango fruits, in which of C. gloeosporioides was found the most prevalent. Phomopsis mangiferae, Botryodiplodia theobromae, Altrnaria spp. Aspergillus niger, A. flavis were found in Chaunsa and Phomopsis mangiferae was most prevalent, while Botryodiplodia theobromae caused infection to locally cosumed Fajri variety. Effect of abiotic factors like pH, temperature, light intensity and carbon sources were tested against these isolates. The most efficient carbon source was glucose, which supported the maximum growth of the P. mangiferae and L. Theobromae, while C. gloeosporioides had maximum growth on lactose. All fungi had maximum growth at pH range of 6-6.5 and temperature range of 25-30 degree C on PDA medium. Alternate cycles of 12hr light and 12 hr darkness resulted maximum mycelial growth as compared to the 24 hour continuous exposure to either dark or light. Susceptibility of fungi with cultivars and intensity of spread under specific abiotic conditions provides basic information in this paper to minimize stem end rot of mango in field and storage conditions. (author)
[en] In order to assess the antifungal activity of methanolic extracts from neem tree (Azadirachta indica A. Juss.), several bioassays were conducted following M38-A2 broth microdilution method on 14 isolates of the dermatophytes Trichophytonmentagrophytes, Trichophyton rubrum, Microsporum canis and Epidermophyton floccosum. Neem extracts were obtained through methanol-hexane partitioning of mature green leaves and seed oil. Furthermore, high performance liquid chromatography (HPLC) analyses were carried out to relate the chemical profile with their content of terpenoids, of widely known antifungal activity. The antimycotic terbinafine served as a positive control. Results showed that there was total growth inhibition of the dermatophytes isolates at minimal inhibitory concentrations (MIC) between 50 μg/mL and 200 μg/mL for leaves extract, and between 625 μg/mL and 2500 μg/ml for seed oil extract. The mic of positive control (Terbinafine) ranged between 0.0019 μg/mL and 0.0313 μg/mL. Both neem leaves and seed oil methanol extracts exhibited different chromatographic profiles by HPLC, which could explain the differences observed in their antifungal activity. This analysis revealed the possible presence of terpenoids in both extracts, which are known to have biological activity. The results of this research are a new report on the therapeutic potential of neem to the control of dermatophytosis.
[en] Editor's note: this article by Robert Curnow was adapted from an article originally published in the February 2001 issue of RSS NEWS, the monthly magazine of the Royal Statistical Society (RSS). I am grateful to Frank Duckworth, the Editor of RSS NEWS, the Royal Statistical Society and Robert Curnow for permission to slightly amend and publish this article. The issue of BSE/vCJD is a dramatic one that has attracted intense publicity and led to a collapse of public trust in scientists and the scientific method. The repercussions may well lead to changes in the way that scientific evidence is assessed, especially in the manner in which government seeks and appraises scientific advice. Clearly, there are implications for radiological protection given the controversial and contentious nature of the current debates concerning the risks to human health (or their absence) posed by exposure to low levels of ionising and non-ionising radiations. The mammoth report of the BSE inquiry chaired by Lord Phillips has been expertly summarised by Robert Curnow in this article and those involved in radiological protection should carefully consider the potential ramifications of what he has written. It is recommended that government departments retain sufficient scientific expertise `in house' to ensure that the advice of advisory committees, and the reasoning behind it, can be understood and evaluated. I am not sure what is meant here by `evaluated' since the science should presumably be sound. Certainly, there needs to be `in house' expertise to act as an intermediary between the advisory committee and policy-makers so that the scientific advice can be properly related to alternative policy options. The report recommends that government should seek advice from the professional or other body best qualified to advise on suitable candidates for membership of advisory committees. The advice of an advisory committee should normally be made public by that committee. The RSS argued this general point when the `Freedom of Information' White Paper was published, but to no effect. The report criticises the impeding of the gathering of data about the extent of the spread of BSE by an embargo within the State Veterinary Service in the first half of 1987 on making information about the new disease public. The epidemiological data collected by the State Veterinary Service should have been made available earlier to others interested in the epidemiology of the disease, including those with experience in human epidemiology. The report argues that the appointment of a research director or `supremo' would have improved the co-ordination of research effort, including the identification of the best sources of expert assistance, and the identification of areas, including epidemiology, where research could profitably have been started earlier or pursued with more vigour
[en] Soil-microbe-plant interactions are known to be intricate and they can greatly influence the crop vigor and yield. Plant growth promoting rhizobacteria (PGPR) containing ACC deaminase can markedly affect plant metabolic processes under stress conditions. In the present study, we isolated 300 bacterial strains from the rhizosphere of maize or apple grown in drought-hit soil including four different locations of the Loess Plateau, China. Of all isolated strains, four with ACC deaminase activity (ranging from 28.88 to 155.12 nmol alpha-ketobutyrate mg-1 h-1) were further studied by determining their biological characters and sequencing the 16S rRNA gene. All four strains showed positive performance in terms of arabinose, citrate utilization, urease, indol, glucose and melibiose. In connection with the results of biochemical characters and phylogenetic analysis, these strains commonly belong to three different genera: Klebsiella, Pseudomonas and Raoultella and four different species: Klebsiella oxytoca, Klebsiella variicola, Pseudomonas fluorescens and Raoultella planticola. Although some researchers have reported their performance under stress conditions, we are the first to report Klebsiella oxytoca, Klebsiella variicola and Raoultella planticola containing ACC deaminase under drought stress. These findings are a reasonable explanation to their superb ability of causing stress-resistance in maize (Zea mays) or apple (Malus domestica) plants. The presence of diverse PGPR possessing potential ACC deaminase activity may be beneficial for enhancing crop production under different stress conditions. (author)