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Luciana Galetto Dimitrios Miliordos Chiara Roggia Mahnaz Rashidi Dario Sacco Cristina Marzachì Domenico Bosco 《Journal of pest science》2014,87(4):671-679
Flavescence dorée (FD) is one of the most economically important grapevine diseases in Southern Europe, and it is associated with phytoplasmas, phloem-limited wall-less bacteria. Recovery from disease naturally occurs in infected grapevines during the following seasons after infection. The capability of the leafhopper vector Scaphoideus titanus to acquire FD phytoplasma (FDP) from recovered and infected grapevines of Barbera and Nebbiolo varieties was investigated in North-western Italy vineyards monitored from 2007 to 2011. Pathogen concentration was quantified by real-time PCR in FDP-infected grapevines and broad beans, also used as source plants under controlled conditions, to correlate acquisition capabilities and phytoplasma titre in source plants. S. titanus acquired FDP from infected, but not from recovered, grapevines. FDP titre was higher in Barbera than in Nebbiolo and higher in summer than in spring, and acquisition efficiency and pathogen titre in source plants were positively correlated, both in field and laboratory conditions. Recovered plants do not represent a source of inoculum for the vector and therefore do not contribute to FDP spread. The inability of recovered plants to serve as FDP acquisition sources for the vector as well as the effect of the season and of the two grapevine varieties on the FDP acquisition efficiency are relevant results to re-design disease management practices, especially since insecticide treatments against the vector are not fully effective, and newly designed successful control strategies are required. 相似文献
2.
Ghorbanali Mohammadpour Roudposhti Akbar Baghvand 《Archives of Agronomy and Soil Science》2016,62(10):1411-1424
The main purpose of the present investigation was to develop a pollution index for agricultural soils. For this purpose, 58 soil samples were collected from agricultural lands in Hamedan Province (Iran). The elemental contents of As, Cd and Co in soil samples and agricultural crops were measured by atomic absorption spectroscopy. The spatial distribution of studied metals was prepared by Kriging method. It is concluded that agricultural activities have led to the higher concentrations of Co, Cd and As. Results of the chemical partitioning studies revealed that a considerable portions of As, Cd and Co in agricultural soils are derived from anthropogenic sources. We believe that pollution index should show values that are in accordance with chemical partitioning data. The newly developed pollution index showed slightly higher values when compared with the previously published indices such as geochemical index (Igeo) and pollution index (Ipoll). The health risk index in the area of study was found to be lower than many other reported ones. Among the studied elements, Co has the highest transfer factor of 17.95 that could be attributed to its lower retention rate. 相似文献
3.
Effect of Bacillus subtilis on Aeromonas hydrophila infection resistance in juvenile freshwater prawn, Macrobrachium rosenbergii (de Man) 总被引：1，自引：1，他引：0
This experiment was carried out to investigate the potential probiotics properties of Bacillus subtilis in protecting of juvenile freshwater prawn, Macrobrachium rosenbergii against Aeromonas hydrophila infection. A B. subtilis bacterium isolated from gut of juvenile prawns was added to the prawns feed at 108 cells g?1 feed. There were significant differences (P < 0.05) between B. subtilis-treated and control groups in growth and survival enhancement of juvenile prawns after 60 days of feeding trial. Sixty days after B. subtilis feeding trial, the prawns were challenged by bath exposure to A. hydrophila (107 cells mL?1) for 28 days. Four weeks after challenge, there was significant difference in the survival of prawns between B. subtilis-treated groups (88.33 %) and control groups (20.81 %; P < 0.05). In addition, the control groups had an unhealthy external appearance, while the treated groups, appeared healthy and normal. From this, it was concluded that the selected B. subtilis may be a promising probiotics for protection of prawns from A. hydrophila infection. 相似文献
4.
The accuracy of the knowledge of mass transfer parameters(effective moisture diffusivity,mass transfer Biot number and mass transfer coefficient) in the case of frying food,is essential and important for designing,modeling and process optimization.This study is undertaken to develop an approach for determining mass transfer parameters during frying of spherical rice cracker in sunflower oil at 150,170 and 190 ℃.These parameters were evaluated from the plots of dimensionless concentration ratios against time of frying.Effective moisture diffusivity,mass transfer Biot number and mass transfer coefficient ranged between 1.24×10-8 to 2.36×10-8 m2/s,1.96 to 2.34 and 5.51×10-6 to 9.70×10-6 m/s,respectively.Effective moisture diffusivity and mass transfer coefficient were found to increase with an increasing frying temperature,whereas mass transfer Biot number decreased.An Arrhenius-type relationship was found between effective diffusivity coefficient and frying temperature. 相似文献
5.
Mahnaz Rashidi Youbert Ghosta Masoud Bahar 《European journal of plant pathology / European Foundation for Plant Pathology》2010,127(2):157-159
Russian olive trees (Elaeagnus angustifolia) showing witches’ broom symptoms typical of phytoplasma infection were observed in the Urmia region of Iran. A phytoplasma
named Russian olive witches’ broom phytoplasma (ROWBp-U) was detected from all symptomatic samples by amplification of the
16S rRNA gene and 16S/23S rDNA spacer region using the polymerase chain reaction (PCR) which gave a product of expected length.
DNA from symptomless plants used as a negative control yielded no product. The sequence of the 16S rRNA gene and 16S/23S rDNA
spacer region of ROWBp-U showed 99% similarity with the homologous genes of members of the aster yellows group. We also detected
a phytoplasma in neighboring alfalfa plants (AlWBp-U) showing severe witches’ broom symptoms. An 1107 bp PCR product from
the 16S rRNA gene showed 99% homology with the corresponding product in ROWBp-U, suggesting the presence of the same phytoplasma
actively vectored in the area. Further observations showed that Russian olive trees with typical ROWB symptoms were present
in an orchard near Tehran which is located over 530 km south-east of the original Urmia site. The corresponding sequence of
this phytoplasma (ROWBp-T) showed 99% homology to that of the ROWBp-U. A sequence homology study based on the 16S rRNA gene
and 16S/23S rDNA spacer region of ROWBp-U and other phytoplasmas showed that ROWBp-U is most closely related to the 16SrI
group. To our knowledge, this is the first report of a phytoplasma infection in a member of the Elaeagnaceae. 相似文献
6.
The concentrations of major heavy metals in organs of two cyprinid fish and in water collected from three sections of the Kor River, Iran, were determined using the induction coupled plasma method. The concentrations of heavy metals in tissue of fish from the middle sampling zone were significantly higher (p?<?0.05) than those from the other two sampling zones, whereas no significant differences (p?>?0.05) were detected between the two sexes and species. Estradiol in females and progesterone and testosterone in males from the middle study site were significantly (p?<?0.05) lower than values from the other two sites. Pathological changes in blood cells, liver, and kidneys of fishes were significantly higher in highly polluted areas (middle sampling zone). So heavy metals exposure can effectively decreases estrogenic and androgenic secretion in fish. These results show that industrial activities have polluted the river and that heavy metals exposure can induce pathological changes in fish organs. 相似文献
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The essential oil of Oliveria decumbens was investigated for its components and antimicrobial activity against six bacteria and two fungal strains. The essential oil was characterized by a high amount of oxygenated monoterpene components of which thymol (47.06%) and carvacrol (23.31%) were the major components. The oil exhibited high antimicrobial activity against all tested Gram+ and Gram- bacteria and fungal strains. 相似文献
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10.
Mehran Avakh Keysami Masoumeh Mohammadpour Che Roos Saad 《Aquaculture International》2012,20(3):499-511
This experiment was carried out to investigate the potential probiotic properties of Bacillus subtilis and suitable methods of administration to the commercial feed in juvenile Macrobrachium rosenbergii (de Man) from 25 August to 25 November 2008. Putative Bacillus subtilis bacterium isolated from juvenile M. rosenbergii intestine was added to commercial prawn feed as a probiotic. Five types of diets were prepared by mixing B. subtilis at level of 108 cells g?1 with commercial feed using different methods consisting mixing, soaking, spraying and bathing. After 60?days, the prawns fed diets at soaking method treated group, showed a higher mean weight gain (2.09) or 328.84% increase in growth over control. There were significant differences (P?<?0.05) in weight gain, feed intake and FCR among soaking method and other treated and control groups. There was significant difference (P?<?0.05) in survival among treated and control groups, but no significant difference (P?>?0.05) in water quality and biochemical composition among treated and control groups. Clearly, B. subtilis-treated diets appeared to enhance growth and survival of juveniles M. rosenbergii. It was concluded that the tested strain may be a promising probiotic for M. rosenbergii under soaking method of administration to the prawn commercial feed. 相似文献