oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2018 ( 2 )

2017 ( 2 )

2016 ( 4 )

2015 ( 98 )

Custom range...

Search Results: 1 - 10 of 2329 matches for " Levi? Jelena "
All listed articles are free for downloading (OA Articles)
Page 1 /2329
Display every page Item
Genetic variability of maize pathogens in Serbia
Stankovi? Slavica,LeviJelena,Ivanovi? Dragica
Genetika , 2007, DOI: 10.2298/gensr0702227s
Abstract: Variability of some maize pathogens was identified in the last 50 years of research in Serbia, mostly by their cultural characteristics and susceptibility of test genotypes and only in some cases by determination of mating types, vegetative compatibility or biochemical methods. Although more advanced methods that can determine within population variability at the molecular level were developed, they are still not applied in research in Serbia. The highest variability was determined for maize leaf pathogens - Exserohilum turcicum (Pass.) Leonard & Suggs (2 races) and Bipolaris zeicola (Stout) Shoemaker (2 races), although this variability is significantly lower than the variability of the same pathogens found in the world. Researches conducted with the aim to determine mating types and vegetative compatibility of the Fusarium species, a maize root and stalk pathogen, indicated their high variability in Serbia. Considering the pathogen ability to adapt easily and quickly to new genotypes, agro-ecological conditions and crop practice, a constant surveillance of parasite divergence and epidemiology is necessary in order to avoid detrimental consequences on maize yield and quality.
The determination of Exserohilum turcicum virulence factors in Serbia
LeviJelena,Stankovi? Slavica,Petrovi? Tijana
Genetika , 2008, DOI: 10.2298/gensr0803271l
Abstract: The determination of Exserohilum turcicum virulence factors and resistance responses of three sets of maize inbred lines (four differential, eight isogenic and 22 commercial inbreeds) to three isolates of this pathogen under greenhouse conditions were studied. The maize inbreeds were selected according to previous testing of resistance based on lesion types in 194 inbreeds under field conditions of plant inoculation with the E. turcicum race 0 (designated as the isolate MRI-Et). The standard procedure was applied to obtained isolates MRIZP-1747 and MRIZP-1416 from resistant and susceptible lesion types, respectively. These lesions were developed on the same leaf of a plant of the experimental hybrid no. 163/99 grown in a nursery at Zemun Polje during 1999. The third isolate (MRIZP-1435) was isolated from a leaf sample originating from the location of Srbobran in which the occurrence of northern corn leaf blight (NCLB), caused by Exserohilum turcicum, was intensive. Based upon virulence/avirulence of three isolates of E. turcicum on differential maize inbred lines, it was found out that the isolate MRIZP-1747 could be classified as race 0, whereas isolates MRIZP-1416 and MRIZP-1435 could be classified as race 1. These are the first results that confirm the presence of race 1 of E. turcicum in Serbia. Not including differential lines, 22 and six lines were resistant to race 0 and race 1, respectively, while eight and five lines were resistant and susceptible to both races, respectively. All isogenic lines not containing the Ht gene were susceptible to both races 0 and 1.
Clinical and neurophysiological findings in oligoclonal band negative multiple sclerosis patients
Mesaro? ?arlota,Drulovi? Jelena S.,Levi? Zvonimir
Srpski Arhiv za Celokupno Lekarstvo , 2003, DOI: 10.2298/sarh0304122m
Abstract: Besides magnetic resonance imaging, the presence of locally produced oligoclonal IgG bands (OCB) in the cerebrospinal fluid (CSF) is the most consistent laboratory abnormality in patients with multiple sclerosis (MS). The most sensitive method for the detection of CSF OCB is isoelectric focusing (IEF) [6]. Occasional patients with clinically definite MS lack evidence for intrathecal IgG synthesis [7, 8]. This study was designed to compare clinical data and evoked potential (EP) findings between CSF OCB positive and OCB negative MS patients. The study comprised 22 OCB negative patients with clinically definite MS [11] and 22 OCB positive controls matched for age, disease duration, activity and course of MS. In both groups clinical assessment was performed by using Expanded Disability Status Scale (EDSS) score [12] and progression rate (PR). All patients underwent multimodal EP: visual (VEPs), brainstem auditory (BAEPs) and median somatosensory (mSEPs). The VEPa were considered abnormal if the P100 latency exceeded 117 ms or inter-ocular difference greater than 8 ms was detected. The BAEPs were considered abnormal if waves III or V were absent or the interpeak latencies I-III, III-V, or I-V were increased. The mSEPs were considerd abnormal when N9, N13 and N20 potentials were absent or when increased interpeak latencies were recorded. The severity of the neurophysiological abnormalities was scored for each modality as follows normal EP score 0; every other EP abnormality except the absence of one of the main waves, score 1; absence of one or more of the main waves, score 2 [13]. Both mean EDSS score (4.0 vs. 3.5) and PR (0.6 vs. 0.5) were similar in OCB positive and OCB negative group, (p>0.05). In the first group males were predominant, but without statistical significance (Table 1). Disease started more often with the brainstem symptoms in the OCB positive than in OCB negative MS group (p=0.028), while there was no differences in other initial symptoms between the groups (Graph 2). The frequency of (multimodal) EP abnormalities was higher in the OCB positive group but the differences were not statistically significant, except for bilateral SEP abnormalities (p=0.012). The severity of the AEPs abnormalities was similar in both groups while for the VEPs and SEPs abnormalities were more pronounced in the OCB positive group but not significantly (Table 2). The male preponderance of OCB negative MS patients in our study is in accordance with previous studies [14, 15]. This finding could be potentially ascribed to the well known gender-related differences in b
Variability of Pathogenicity of Fusarium spp. Originating from Maize and Wheat Grains
Sonja Tan?i?,Slavica Stankovi?,Jelena Levi
Pesticidi i Fitomedicina , 2009,
Abstract: Differences in the pathogenicity of 93 isolates of seven species belonging to the genus Fusarium (F. graminearum, F. verticillioides, F. proliferatum, F. subglutinans, F. sporotrichioides, F. semitectum and F. equiseti), originating from maize kernels (61) and wheat grains (32), were examined based on the germination percentage of inoculated seeds. The studied species demonstrated inter- and intraspecies variability regarding the effects on maize seed germination. On the average, the greatest germination reduction was found in seeds inoculated with the spore suspensions of F. sporotrichioides and F. graminearum. A similar reduction was detected in seeds inoculated with F. proliferatum and F. subglutinans. The effect of F. subglutinans on seed germination reduction was higher compared to the two latter species, while the effects of F. semitectum and F. equiseti were smallest. The majority of isolates were of moderate pathogenicity, while the lowest number of isolates was either very pathogenic (7) or apathogenic (10). Pathogenicity of the isolates originating from wheat grains was generally lower than the pathogenicity of isolates originating from maize kernels, with the exception of F. sporotrichioides.
Diversity of the Fusarium verticillioides and F. proliferatum isolates according to their fumonisin B1 production potential and origin
Tan?i? Sonja,Stankovi? Slavica,LeviJelena,Krnjaja Vesna
Genetika , 2012, DOI: 10.2298/gensr1201163t
Abstract: Species of the genus Fusarium are characterised by the exceptional intraspecies and interspecies variability in respect to morphological, physiological and genetic properties. Intraspecies and interspecies diversity of Fusarium verticillioides and Fusarium proliferatum isolates in the production of fumonisin B1 according to their origin from maize and wheat grains was studied. Fumonisin B1 production potential of investigated 42 isolates was assessed by HPTLC and ELISA method. All 22 and 20 investigated F. verticillioides and F. proliferatum isolates, respectively, had the ability to produce fumonisin B1 toxin. Fumonisin B1 production potential of F. verticillioides and F. proliferatum varied from 88.60 ppm to 1,300.60 ppm and from 2.37 ppm to 1,246.00 ppm, respectively. According to Mann-Whitnev U test, there were no significant differences between the fumonisin B1 production mean values of isolates of F. verticillioides originated from maize and wheat (628.13 ppm and 696.38 ppm, respectively), as well as, fumonisin B1 production mean values of F. proliferatum isolates (212.32 ppm and 158.07 ppm, respectively). Variability coefficient values indicated that fumonisin B1 production potential variability was more expressed in maize than wheat originated isolates for both species.
Brain MRI in patients with multiple sclerosis with oligoclonal cerebrospinal fluid bands
Mesaro? ?arlota,Drulovi? Jelena S.,Levi? Zvonimir,Peri? Vesna
Srpski Arhiv za Celokupno Lekarstvo , 2003, DOI: 10.2298/sarh0302031m
Abstract: Locally produced oligoclonal IgG bands (OCB) are present in the cerebrospinal fluid (CSF) of 95% patients with multiple sclerosis (MS)[2,3]. The most sensitive method for the detection of OCB is isoelectric focusing (IEF) [1]. Occasional patients with clinically definite MS lack evidence for intrathecal IgG synthesis [2,9]. This study was designed to compare brain magnetic resonance imagining (MRI) findings between CSF OCB positive and negative MS patients. The study comprised 22 OB negative patients with clinically definite MS and 22 OCB positive controls matched for age, disease duration, activity and course of MS. In the both groups clinical assessment was performed by using Expanded Disability Status Scale (EDSS) score. T2 weighted MRI of the brain was performed on a Siemens Magnetom (1.0 T). Lesions were countred and sized for 15 anatomically defined locations:7 periventricular (PV) and 8 non-periventricular (NPV) regions. An arbitrary scoring system weighted for lesions size was used to estimate total and regional lesions loads: a)1 point was given for each lesion with a diameter 1-5 mm, b) 2 points for one lesion with a diameter 6-10 mm, c) 3 points for one over 10 mm, and confluent lesions scored one extra point [16]. Atrophy were scored as follows: 0-normal size, 1-mild atrophy, 2-moderate atrophy and 3-severe atrophy. Mean score of total brain MRI loads was lower in OCB negative than in OCB positive MS patients (44 vs. 50) but the difference was not statistically significant. Mean periventricular (32 vs. 23) non-periventricular (26 vs. 19) and infratentorial (11 vs. 9) scores were higher in OCB positive MS group in comparison with OCB negative patients but non-significant (figure 1). There was no correlation between EDSS score and total MRI lesions load in OCB negative MS patients, while in OCB positive group we detected significant correlation between EDSS score and total MRI lesions load (p=0.026) (figure 2). The results of this study demonstrate that by using conventional brain MRI the extent end severity of the pathological process seems to be similar in OCB negative and OCB postive MS patients. On the other hand, we found statistically significant correlation between brain MRI total lesion load and EDSS in the OCB positive MS patients, while this correlation was not detected in OCB negative MS patients. Differences in brain MRI findings between OCB positive nad OCB negative MS patients have been already analyzed [9,12]. In the first, Zeman et al. reported that OCB negative MS patients have lower total MRI brain lesion loads in comparison t
Fusariotoxins in Wheat Grain in Serbia
Ana Stepani?,Slavica Stankovi?,Jelena Levi,Mirko Ivanovi?
Pesticidi i Fitomedicina , 2011,
Abstract: Samples of wheat grain (41), collected during the 2010 harvest from seven localities inSerbia, were analysed for the presence of zearalenone (ZEA), T-2 toxin, deoxynivalenol (DON)and fumonisine B1 (FB1). Results of Enzyme-Linked Immunosorbent Assay (ELISA) showedthat all analysed samples were positive for the presence of at least one of four observedfusariotoxins. The most distributed mycotoxins were ZEA (90.2%, with the average concentrationof 442.6μg kg–1) and T-2 (90.2%, with the average concentration of 24.2 μg kg–1).DON (73.2%) and FB1 (84.4%) were detected in a somewhat smaller number of samples, buttheir average concentrations were higher (1988.1 μg DON kg–1 and 882.7 μg FB1 kg–1). Theestablished correlations between concentrations of DON and FB1 (r = 0.32) or DON and ZEA(r = 0.22) were not statistically significant. A negative correlation was established betweenconcentrations of T-2 and FB1 (r= -0.24), as well as, between T-2 and DON (r = -0.36). Detectedconcentrations of ZEA and T-2 were bellow the level prescribed by the World Health Organisation(WHO), while concentrations of FB1 and DON detected in five that is, 17 samples,respectively, were above the permissible limit for human consumption
Pathogenicity of P. terrestris on Maize Seedlings
Jelena Levi,Tijana Petrovi?,Slavica Stankovi?,Dragica Ivanovi?
Pesticidi i Fitomedicina , 2012,
Abstract: Pathogenicity of P. terrestris was determined by the Knop’s medium slants method intest tubes. Isolates originated from the roots of maize (Zea mays L.), barley (Hordeum vulgareL.), Johnson grass (Sorghum halepense Pers.), sorghum (Sorghum bicolour (L.) Moench.), garlic(Allium sativum L.), onion (Allium cepa L.), barnyard millet (Echinochloa crus-galli (L.) P.Beauv.)and green foxtail (Setaria viridis (L.) P.B.). A fragment of a fungal colony, cultivated on PDA,was placed on the bottom of Knop’s medium slant in each test tube and then steriliseda maize seed was placed 2 cm away from the inoculum. After 21-day inoculation of seeds,the intensity of the development of symptoms on maize seedlings was estimated. The reddishor dark pigment on the root, mesocotyl and/or coleoptyl of seedlings was an indicatorfor the infection by the fungus under in vitro conditions. Based on the pathogenicity test,the isolates were classified into the following three groups: slightly (3 isolates), moderately(6 isolates) and very pathogenic (6 isolates) to maize seedlings. The obtained results showthat P. terrestris, originating from different hosts, can be a maize pathogen. These resultscan explain the high frequency and high incidence of this fungus on maize roots in Serbia.
Virulence of Fusarium species to alfalfa seedlings
Krnjaja Vesna,LeviJelena,Ivanovi? M.,Tomi? Zorica P.
Zbornik Matice Srpske za Prirodne Nauke , 2005, DOI: 10.2298/zmspn0508167k
Abstract: In in vitro conditions, virulence of 91 isolates of species Fusarium genus (F. oxysporum, F. solani, F. acuminatum, F. equiseti, F. arthrosporioides, F. prolifera- tum, F. avenaceum, F. semitectum, F. tricinctum, F. sporotrichioides and F. graminearum) towards alfalfa seedlings was investigated. Isolates of investigated species originated from diseased alfalfa plants collected at four locations in Serbia based on symptoms of wilting caused by Fusarium and root rotting. Pathogenicity and virulence of investigated isolates of Fusarium spp. were determined by visual evaluation of inoculated seedlings of cultivar K28 in laboratory conditions. All isolated of investigated species had pathogenic effect on alfalfa seedlings which expressed symptoms such as necrosis of root, moist rotting and "melting of seedlings". Colour of necrotic root tissue varied from light brown, brown lipstick red to explicit black, depending on the Fusarium species. Strong virulence was established in 48 isolates, medium virulence in 31 and weak virulence in 12 isolates.
Virulence of Fusarium species to alfalfa seedlings
Krnjaja Vesna,LeviJelena T.,Ivanovi? Mirko,Tomi? Zorica P.
Zbornik Matice Srpske za Prirodne Nauke , 2005, DOI: 10.2298/zmspn0519065k
Abstract: In in vitro conditions, virulence of 91 isolates of species Fusarium genus (F. oxysporum, F. solani, F. acuminatum, F. equiseti, F. arthrosporioides, F. proliferatum, F. avenaceum, F. semitectum, F. tricinctum, F. sporotrichioides and F. graminearum) towards alfalfa seedlings was investigated. Isolates of investigated species originated from diseased alfalfa plants collected on four locations in Serbia based on symptoms of wilting caused by fusarium and root rotting. Pathogenicity and virulence of investigated isolates of Fusarium spp. were determined by visual evaluation of inoculated seedlings of cultivars K28 in laboratory conditions. All isolated of investigated species had pathogenic effect on alfalfa seedlings, which expressed symptoms such as necrosis of root, moist rotting and "melting of seedlings". Colour of necrotic root tissue varied from light brown, brown, lipstick red to explicit black, depending on the Fusarium species. Strong virulence was established in 48 isolates, medium virulence in 31 and weak virulence in 12 isolates.
Page 1 /2329
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.