Wyniki wyszukiwania - AGRO

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Components of quantitative resistance to downy mildew [Plasmopara halstedii] in sunflower [Helianthus annuus]

100%

Sakr N.

Journal of Plant Protection Research

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2009

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tom 49

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nr 3

297-301

Components of quantitative resistance in sunflower (Helianthus annuus) to Plasmopara halstedii, the pathogen causing downy mildew, were investigated. Percentage infection, latent period, sporulation density and reduction of hypocotyl length were compared on two sunflower lines showing different levels of quantitative resistance in the field infected with different P. halstedii strains of races 100, 300, 710 and 714 in controlled conditions. The inbred line BT, rather susceptible in the field, showed a higher percentage infection, a higher sporulation density, a shorter latent period and less reduced hypocotyl length than inbred line FU, which showed a greater resistance in the field. The very good resistance of inbred line FU observed in the field was confirmed by the measurements of quantitative resistance criteria described in this study. Percentage infection of FU was 1.4% less than BT, latent period of BT was 12.4% less than FU, sporulation density of FU was 22.3% less than BT and reduced hypocotyl length of BT was 15.3% less than FU. It seems that the criteria such as latent period, sporulation density and reduction of hypocotyl length may be used to measure quantitative resistance in sunflower to P. halstedii.

2

The relationship between H. pylori virulence genotypes and gastric diseases

100%

Liu Y. E., Gong Y. H., Sun L. P., Xu Q., Yuan Y.

Polish Journal of Microbiology

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2012

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tom 61

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nr 2

There have been no reports on the relationship between virulence genes and gastric diseases based on the same bacterial colonization density. Our results indicated that Helicobacter pylori virulence genes were more relevant than colonization density as a pathogenic mechanism of gastric diseases, which helps elucidate the pathogenic mechanisms of bacteria and aids in the development of improved strategies for the treatment of gastric disease.

3

Studies on biochemical indicators of virulence in the Amoebae of the Acanthamoeba sp.

100%

Hadas E., Mazur T.

Acta Protozoologica

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1991

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tom 30

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nr 3-4

4

Virulence frequency of Blumeria graminis f.sp. hordei and the occurrence of powdery mildew on four winter barley cultivars

100%

Tratwal A., Weber Z.

Journal of Plant Protection Research

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2006

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tom 46

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nr 3

221-230

Powdery mildew caused by Blumeria graminis f. sp. hordei is one of the most important diseases of barley in Poland. B. graminis is a genetically diverse pathogen with different special forms and races. The aim of the two-years’ experiment was to assess of B. gramins f. sp. hordei virulence frequency and powdery mildew occurrence on four winter barley cultivars. Virulence frequency of the pathogen depended on place and term of exposition. The occurrence of powdery mildew on four winter barley cultivars depended on virulence frequency of the pathogen and weather conditions.

5

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Virulence and antibiotic resistance of Escherichia coli isolated from rooks

100%

Kmet V., Drugdova Z., Kmetova M., Stanko M.

Annals of Agricultural and Environmental Medicine

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2013

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tom 20

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nr 2

With regard to antibiotic resistance studies in various model animals in the urban environment, the presented study focused on the rook, many behavioural and ecological aspects of which are important from an epidemiological point of view. A total of 130 Escherichia coli strains isolated from rook faeces during a two-year period (2011–2012) were investigated for antibiotic resistance and virulence. Resistance to ampicillin (60%) and streptomycin (40%) were the most frequent, followed by resistance to fluoroquinolones (ciprofloxacin-22% and enrofloxacin-24%), tetracycline (18%), cotrimoxazol (17%) and florfenicol (14%). Ceftiofur resistance occured in 10.7 % of strains and cefquinom resistance in 1.5 % of strains. Twenty-five E.coli strains with a higher level of MICs of cephalosporins (over 2mg/L of ceftazidime and ceftriaxon) and fluoroquinolones were selected for detection of betalactamase genes (CTX-M, CMY), plasmid-mediated quinolone resistance qnrS, integrase 1, and for APEC (avian pathogenic E.coli) virulence factors (iutA, cvaC, iss, tsh, ibeA, papC, kpsII). Genes of CTX-M1, CMY-2, integrase 1, papC, cvaC, iutA were detected in one strain of E.coli, and qnrS, integrase 1, iss, cvaC, tsh were detected in another E.coli. DNA microarray revealed the absence of verotoxin and enterotoxin genes and pathogenicity islands. The results show that rooks can serve as a reservoir of antibiotic-resistant E. coli with avian pathogenic virulence factors for the human population, and potentially transmit such E.coli over long distances.

6

QS - systems communication of Gram-positive bacterial cells

100%

Ziemichod A., Skotarczak B.

Acta Biologica

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2017

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tom 24

7

Analysis of the peptidoglycan hydrolases of Listeria monocytogenes: multiple enzymes with multiple functions

100%

Popowska M.

Polish Journal of Microbiology

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2004

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tom 53

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nr Suppl.

Listeria monocytogenes is a ubiquitous gram-positive, rod-shaped, widespread in nature, facultative intracellular human and animal pathogen that causes infections collectively termed listeriosis. L. monocytogenes EGD encodes a total of 133 surface proteins, the abundance of which, as well as the variety of anchoring systems, probably reflects the ability of this bacterium to survive in diverse environments and to interact with many kinds of eukaryotic cells. The group of surface proteins also includes proteins with murein hydrolase activity-autolysins. To date, five L. monocytogenes autolysins have been identified: p60, P45, Ami, MurA and Auto. These enzymes are involved in numerous cellular processes including cell growth, cell wall turnover, peptidoglycan maturation, cell division and separation, formation of flagella, sporulation, chemotaxis and biofilm formation, genetic competence, protein secretion, the lytic action of some antibiotics and pathogenicity. We have recently identified a putative sixth listerial peptidoglycan-degrading enzyme, which has surprisingly been identified as FlaA, a flagellar protein of L. monocytogenes.

8

The determination of physiological race of Fusarium oxysporum f.sp.lycopersici of tomato in Zhejiang, China

100%

Zhihao X., Kaimay H., Weiling S., Sengjiu Z., Guojing L., Liping C., Zhihui X., Hongxia W., Xiuchu X., Guangliang X., Baishen J.

Acta Physiologiae Plantarum

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2000

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tom 22

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nr 3

9

Effect of culturing Phytophthora infestans on various substrates on expression of its virulence and aggressiveness to potato

100%

Zarzycka H.

Phytopathologia Polonica

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1995

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tom 09

10

Differences in inhibition of apoptosis depending on the virulence of used herpes simplex virus type 1 strains. Function of interferon alpha in apoptotic death of virus infected cells

100%

Rechnio M., Litwinska B.

Acta Microbiologica Polonica

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2003

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tom 52

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nr 3

11

Virulence of Erwinia and Pseudomonas species associated with soft rot in Poland

100%

Zolobowska L., Pospieszny H.

Phytopathologia Polonica

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2001

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tom 22

12

The virulence of Clavibacter michiganensis subsp. insidiosus strains and tests of alfalfa varieties for resistance to the wilt pathogen

100%

Vichova J., Kozova Z.

Journal of Plant Protection Research

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2004

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tom 44

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nr 2

Bacterial wilt caused by Clavibacter michiganensis subsp. insidiosus (Cmi) is an integral part of chronic vascular wilt of alfalfa. The aim of the presented study was to determine the virulence of Cmi strains and later on to evaluate the level of resistance of alfalfa varieties registered in the Czech Republic and of some standard check varieties. Three methods of inoculation were compared at greenhouse conditions. The severity of the disease was determined on the basis of symptoms appearing on the cross section of the roots. The Cmi strain 12/5/98 and its re-isolates showed a high level of virulence. Freeze-dried isolates lost their virulence. The best differentiation of tested varieties according to the level of resistance was obtained by using successive inoculation on cotyledons, stems and roots. Of tested alfalfa varieties, Vernal and Roamer were classified as resistant and Nitranka, Orca and Europe as the most susceptible. Alfalfa varieties (Czech and European) registered in the Czech Republic recently proved lower disease severity in comparison with ones registered formerly (r = –0.538, p (0.05) = 0.553). The above mentioned fact evidences the progress of Cmi resistant alfalfa breeding in Europe

13

Staphylokinase production by clinical Staphylococcus aureus strains

100%

Wieckowska-Szakiel M., Sadowska B., Rozalska B.

Polish Journal of Microbiology

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2007

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tom 56

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nr 2

One of virulence factors produced by Staphylococcus aureus is staphylokinase (SAK), which enhances their proteolytic activity leading to tissue damage and improving bacterial invasiveness. In the present study we estimated the ability to produce staphylokinase by 95 S. aureus reference strains and clinical isolates from the airways of cystic fibrosis patients, from skin lesions and from infected bones. We would like to verify any relationship between SAK production and the types of clinical isolates as well as other biochemical properties and activities of these staphylococcal strains, which can be important for their pathogenicity. More than 62% of all tested strains were able to produce secreted type of SAK. Staphylokinase production was significantly more common in the isolates from skin and soft tissue infections than in any other group of tested staphylococci. The general tendencies in the selected properties or activities of both SAK(-) and SAK(+) isolates were similar. Our data confirm phenotypic dissimilarity in SAK production of S. aureus strains isolated from various types of infections. It is compatible with the biological role of staphylokinase and with hypothetical model of staphylokinase mediated bacterial invasion of host tissues. Thus, the estimation of SAK production by S. aureus isolates may be regarded as the parameter describing potential invasiveness of staphylococci and can be useful as a medical recommendation for the eradication of staphylococci carrier state.

14

Barley powdery mildew in Slovakia: the development and complexicity of virulence in 1994-1996

100%

Plesnik S., Krippel E., Galova E., Sykora M.

Biological Bulletin of Poznań. Supplement

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1997

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tom 34

15

The impact of environmental stress on Listeria monocytogenes virulence

84%

Walecka E., Molenda J., Bania J.

Polish Journal of Veterinary Sciences

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2009

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tom 12

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nr 4

Listeria monocytogenes, a significant food-borne pathogen, must defy a variety of conditions encountered in the food environment and during the infection process. In reaction to adverse conditions, the bacteria significantly change their metabolism, inducing a stress response which is mediated by a range of alternative sigma factors. The extent of the response to stress was shown to vary in the L. monocytogenes population. According to recent evidence a major L. monocytogenes alternative sigma factor, designated sigma B (σB), regulates some virulence genes in response to stress, which supports an older hypothesis that stress-resistant strains should be more pathogenic. The induction of σB-dependent genes may also be important from the point of view of food hygiene. It seems that stress response activation can paradoxically enhance resistance to agents used in food preservation. Therefore, monitoring the expression of σB-dependent genes can serve as a useful marker to assess the innate resistance of L. monocytogenes strains. This knowledge will allow the design of new methods with sequential preservation steps that could inactivate the bacteria without inducing their stress response.

16

Chorobotworczosc maczniaka prawdziwego jeczmienia [Blumeria graminis f.sp. hordei] w Polsce w roku 2000

84%

Czembor H. J., Czembor J. H.

Biuletyn Instytutu Hodowli i Aklimatyzacji Roślin

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2004

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nr 233

107-115

17

Isolation, characterization and toxicity of native Bacillus thuringiensis isolates from different hosts and habitats in Iran

84%

Ghassemi-Kahrizeh A., Khoramnezhad A., Talaei-Hassanloui R.

Journal of Plant Protection Research

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2017

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tom 57

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nr 3

Bacillus thuringiensis is a Gram-positive, aerobic, facultative anaerobic and endosporeforming bacterium. Different strains of this species have the ability to produce parasporal crystalline inclusions which are toxic to larvae of different insect orders and other invertebrates and cause rapid death of the host. To determine the importance of this species in microbial control, we collected native strains and studied their virulence on the diamondback moth, Plutella xylostella. More than 148 samples were collected from Alborz, Guilan and Mazandaran Provinces. Experimental samples, including soil samples from forests, fruit gardens, agricultural fields, diseased and dead larvae, were transferred to a laboratory in sterile plastic containers. For evaluating B. thuringiensis isolates virulence, a cabbage leaf dip method with 106 cell ⋅ ml–1 concentration of various Bt isolates was applied to diamondback moths. Larval mortality was recorded 72 h after treatment. Based on bioassay results, all isolates were classified into three high, medium and low virulence groups. Protein level characterization based on the SDS-PAGE gel analysis showed that two isolates from a high virulence group have proteins of high molecular masses of 121 and 109 kDa. Results revealed that there is a positive correlation between protein masses and virulence of isolates. In addition, this research introduced nine strains that are highly toxic to P. xylostella and would be valuable as insecticidal agents for controlling lepidopteran pests.

18

A plant mixture model against Plasmopara halstedii [sunflower downy mildew]

84%

Sakr N.

Journal of Plant Protection Research

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2010

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tom 50

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nr 2

125-129

Sunflower downy mildew caused by Plasmopara halstedii is one of the most potentially important diseases. So far, a complete, major gene resistance (Pl) has been used successfully. But, with the appearance of eight races in France since 2000, research on more durable resistance was undertaken. In this study, we presented new results concerning the evolution of pathogenicity in P. halstedii under conditions of re-enforced infection and different Pl gene selection pressure. Moreover, we studied the evolution of virulence and aggressiveness of P. halstedii under a mixture model of sunflower inbred lines carrying the two types of resistance (qualitative and quantitative). This sunflower model may enhance durable resistance against P. halstedii.

19

Virulence of Puccinia recondita f. sp. tritici on winter wheat in Ukraine in 2007

84%

Elyasi-Gomari S., Mikhailovno L. G.

Journal of Plant Protection Research

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2009

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tom 49

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nr 4

382-389

Thatcher and 36 near-isogenic Thatcher lines with different Lr genes for resistance to Puccinia recondita f. sp. tritici were planted in field plots at one location each in the eastern and central parts of the forest-steppe region of Ukraine where they were exposed to natural epiphytotics of leaf rust. Disease severity on the lines indicated that Lr9, Lr19, Lr24, Lr25, and Lr28 had highly effective resistance in both locations. Lines with Lr27+Lr31, Lr35, and Lr36 were resistant in the eastern location and highly resistant in central location. Bulk collections of P. recondita from fields of nine Ukrainian winter wheat cultivars in the eastern location were inoculated onto seedlings of each of the 36 Thatcher near-isogenic lines. Lines with Lr9, Lr19, Lr24, Lr25, and Lr28 remained free or nearly free of uredinia. A total of 133 single-uredinial isolates obtained from 19 susceptible Thatcher near-isogenic lines in field plots in the central part of the forest-steppe region were identified to race using the eight standard leaf rust differential varieties of Johnson and Browder. The most common races were races 6 (27.8%), 77 (18.0%), 149 (13.5%), and X-4 (9.8%). The three most common races were not found on the Lr26 line and may lack virulence to it.

20

Characterisation of classical enterotoxins, virulence activity, and antibiotic susceptibility of Staphylococcus aureus isolated from Thai fermented pork sausages, clinical samples, and healthy carriers in Northeastern Thailand

84%

Sankomkai W., Boonyanugomol W., Kraisriwattana K., Nutchanon J., Boonsam K., Kaewbutra S., Wongboot W.

Journal of Veterinary Research

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2020

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tom 64

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nr 2

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