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Результаты 11-20 из 57
Stenotrophomonas rhizophila a Novel Plant-Associated Bacterium With Distinguished PGPRs Properties
2023
Elhosieny, Asmaa | Zayed, Mona | Selim, Shawky | Abdel Aziz, Norhan
Stenotrophomonas sp. is a plant-associated rhizospheric bacteria. It has the capability to enhance plant productivity. It acts as a mineral dissolution and growth promoter for plants under salt-stress conditions. The selected isolates revealed the general morphological and biochemical characteristics of Stenotrophomonas sp. All the isolates exhibited the highest growth density after 15 hr. at 30˚C, resistance to different levels of salinity, different pH levels, and different temperature degrees. Also, the isolates revealed their capabilities to solubilize phosphorus and potassium and to pro-duce different phytohormones. The isolate X.M9 exhibited the highest growth performance in the form of 1.376,1.326,1.292,1.053 and 1.059 OD in most salts’ concentrations compared to all tested isolates respectively. As well it (X.M9) exhibited the highest resistance to low temperatures 10 and 15oC being 0.917 and 1.354 OD respectively. The isolate X.M9 recorded the highest IAA of 83.73 mg/100ml compared to all the tested isolates. The isolate X.M9 were identified using 16 SRNA sequencing and submitted to the GenBank database under accession number No: OP050187 as Stenotrophomonas rhizophila.
Показать больше [+] Меньше [-]Isolation and Characterization of Probiotics from Various Food Products as Potential Human Food Additives
2023
Mohamed Ali, Fekria | Abdelhafez, Ahmed | Hassan, Enas | Abd-Elhalim, Basma
In this study, human-safe lactic acid microorganisms (LAM) were isolated from food samples to be used as potential additives for human food. Samples from various food sources (artisanal cheeses, fermented chickpeas, fermented rice, natural yogurt, pickles, and raw milk) were used to inoculate de Man, Rogosa, and Sharpe (MRS) and malt agar plates, which were incubated at 30°C for 48 h or 37°C for 72 h to isolate lactic acid bacteria and yeast, respectively. Out of 120 isolates (85 bacteria and 35 yeast), 75 isolates showed γ-hemolytic activity and were considered “Generally Recognized As Safe” (GRAS) isolates. After testing their growth rate under the gastrointestinal tract (GIT) conditions, including acidic pH and specific bile salt concentrations, we selected 30 isolates. Then, we evaluated the fermentative abilities of these 30 isolates on nine types of carbohydrates, their total acidity, and their antagonistic activity against five human pathogens. Based on the results of these tests, four isolates were selected for identification using the Biolog program and 16S rRNA sequencing for bacteria and 18S rRNA sequencing for yeast and found to be Bacillus bingmayongesis (FJAT-13831),Lacticaseibacillus paracasei (R094), Pediococcus pentosaceus (DSM20336), and one yeast isolate as Saccharomyces cerevisiae (SaCe1 26S).
Показать больше [+] Меньше [-]Decreasing of Monosaccharide Contents Resulted From Cold- Induced Sweetening in Tetraploid Potato (Solanum tuberosum L.) Using Genome Editing
2023
Hassan, Sally | Abdel-Salam, Mohamed | hanfy, ayman | Abd-Elhalim, Haytham | Ahmed, Nouh | Metry, Emad
Worldwide, potato (Solanum tuberosum L.) is one of the most essential agro-economically food crops. To ensure its presence throughout the year for food processors and to extend its shelf life, it should be stored in cold temperatures. Despite the benefits of storage at low temperatures, it causes undesirable phenomena; one of them is cold-induced sweetening, which reduces the quality and the commercial value of the potato tubers. In this study, the CRISPR technology ″Clustered Regularly Interspaced Short Palindromic Repeats″ has been used in potato cultivar Desiree via Agrobacterium mediated transformation to edit starch phosphorylase gene that is responsible for starch degradation in cold temperature storage, after regeneration steps. The regenerated plants were used in the screening of genome editing by Sanger sequencing and the ICE program. Screening results showed that Desiree 2 (DE2), Desiree 7 (DE7) and Desiree 27 (DE27) lines have mutations in sgRNA sequence that indicated a significant reduction in reduced sugar contents of tubers after cold storage for 90 and 120 days. The reduction mean values were 29.224, 35.078 and 35.862 in DE2, DE7 and DE27 respectively after 90 days and 83.212, 56.674 and 34.109 after 120 days without visible differences in plant morphology and tubers
Показать больше [+] Меньше [-]Role of Vitamin C Supplementation in Alleviation of Aflatoxin-Contaminated Feed of Nile tilapia (Oreochromis niloticus)
2023
El-Nahal, Sara | Amer, Mohamed | Osman, Mohamed | Ahmed, Kareem
The purpose of the research was to illustrate the effects of feeding Nile tilapia fingerlings (Oreochromis niloticus) with low doses of aflatoxins (AFs) with and without vitamin C supplementation to investigate the capacity of vitamin C in detoxification. Ten experimental diets were formulated and divided into three categories. The first category included: T1, T4 and T7 feedings included 20, 40 and 80 μg AFs kg−1 feed respectively, while both the second category T2, T5 and T8 and the third category T3, T6 and T9 were treated with contaminated feed with AFs for 57days then both categories shifted to different regime till the conclusion of the experimentation. The second category was fed uncontaminated feed while the third category was fed a supplemented diet with 100 mg Kg-1 of vitamin C. For 113 days the experiment was conducted. The results showed that shifting from a contaminated diet to an uncontaminated diet (category 2) or adding vitamin C to the contaminated diet (category 3) improved the deterioration that occurred in the values of growth performance, biochemical parameters and histological disorders caused by AFs. Furthermore, the results from the control group were superior to all the treatments.
Показать больше [+] Меньше [-]Efficacy of Potassium Fertilizer and Certain Pesticides for the Management of Brinjal Fruit Infection by Shoot Borer [Leucinodes Orbonalis (Guenée)]
2023
bhandari, Sagar | kandel, Bikash | gyawali, Pramod | pokhrel, Saurav | ojha, Sushil | bhandari, Sarita
The research aims to evaluate the efficacy of different levels of potassium fertilizer (8 g/plant K2O) as well as the insecticides neemix, spinosad, and imidacloprid at the rates of 6 ml, 0.33 ml, and 0.33 g/L water, respectively, for the management of brinjal fruits and shoot borer. The two-factor randomized complete block design with three replications was used. Significant minimum shoot damage was recorded in the plots treated with imidacloprid (0%), spinosad (1.67%) and neemix (5.0%) at 81 days after planting. Similarly, a significant minimum fruit infestation (2.90%) was recorded with imidacloprid, which was lower than those of spinosad (15.16%) and neemix (19.63%). The application of potassium fertilizer at a rate of 8 g/plant showed a significant reduction in shoot infestation (2.50%) 81 days after planting. The minimum percentage yield of infested fruit was reported with spinosad (1.03%), which was at par with other insecticidal treatments. Considering the negative impacts of chemical pesticides, neemix 6 ml/L water in combination with potassium fertilizer at 8 g/plant is recommended.
Показать больше [+] Меньше [-]Morphological and Molecular Identification of Penicillium digitatum Causing Green Mould of Citrus Fruits in Egypt
2023
Desouki, Abdalrahman | Ahmed Reda, Labiba | Rashed, Mohamed | Shehata, Shehata
Nine Penicillium digitatum isolates were isolated from citrus fruits and tested for their pathogenicity on Navel orange fruit (Citrus sinensis L.). In this regard, the isolates exhibited three different levels of virulence. The isolates were identified morphologically using malt extract agar (MEA) and Czapek yeast extract agar (CYA) for colony characteristics, and MEA for microscopic features. Each one of the isolates has the unique features of P. digitatum, especially the largest conidia (6.1-11.9 µm long X 3.2-8 µm width), and phialides (10.1-21.4 µm long X 4-5.1 µm width). In addition, the isolates were identified on a molecular basis using ITS1 and ITS4 primers to confirm morphological identification. Phylogenetic analysis revealed that there was high variance among the isolates, and there were different relations between some of our isolates and other P. digitatum registered strains originating from different countries all over the world. The sequences were submitted to respective GenBank nucleotide databases with accession No. OR198852, OR198853, OR198854, OR198855, OR198856, OR198857, OR198858, OR198859 and OR198860. We also isolated a new P. digitatum (OB15: OR198859) strain with high virulence and rapid sporulation
Показать больше [+] Меньше [-]The Relationship Between Vegetation Type and Population Density-Diversity of Spiders in Certain Vegetable Crops
2023
Abd El-Karim, Hamdi | Rizk, Marguerite
The experiment was carried out on three different vegetable crops, Cucumber Cucumis sativus L. (Cucurbitaceae), eggplant Solanum melongena L. (Solanaceae) and okra Abelmoschus esculentus L. (Malvaceae), during summer 2021, to investigate the effect of vegetation type on spider density and diversity. For this study, the pitfall trap method was used to collect spiders from the soil surface to ensure a comprehensive representation of all spider guilds. During this study, 20 species belonging to 6 families were collected. The results showed that a total of 374, 285 and 194 individuals belonging to 18, 17 and 15 species were recorded in okra, cucumber and eggplant fields respectively. Species diversity was greater in okra cultivation. Results also indicated that the Lycosidae family was the most abundant and dominant, representing 71.75%, followed by the Linyphiidae family of 90 individuals representing 10.55% of the whole obtained population. The most dominant species were Wadicosa fidelis 152, 98 and 67 individuals and Pardosa injucunda 111, 69 and 52 individuals in okra, cucumber and eggplant respectively. It is inferred from this study that the type of plant can have an impact on spider communities.
Показать больше [+] Меньше [-]Evaluation of Biologically Treated Olive Mill Wastewater for Irrigation of Pea Plant
2023
Abdelhafez, Ahmed | yehia, Rokia | Abdelaal, Azza
This study evaluated the use of biologically treated olive mill wastewater (OMWW) for irrigation of pea plants, rather than discharging this nutrient-rich liquid and polluting the environment. Pea seeds were planted in pots containing soil irrigated with tap water (control), untreated (crude) OMWW, or OMWW treated with the fungus, Pleurotus columbinus, or algae Spirulina platensis or Wollea sp., with two NPK rates. Plant length shoot and root dry weight, nitrogen, phosphorus, potassium, chlorophyll, and carotene contents were measured, along with to nitrogenase and dehydrogenase activity. The highest shoots N and P content were recorded in plants irrigated with Sp. Platensis-treated OMWW + 100% NPK; while the highest K content was in plants irrigated with crude OMWW + 100% NPK. The highest dehydrogenase activity, 59.01 μg TPF/100 g soils, was recorded in plants irrigated with P. columbinus-treated OMWW supported with 75% NPK, while maximum nitrogenase activity (261.82 μmol/100g soil/day) occurred in plants irrigated with Wollea sp.-treated OMWW with 75% NPK. The highest content of chlorophylls a & b and carotene (0.838, 0.276, 0.252 mg/g dry weight, respectively) were found in plants irrigated with OMWW treated with Wollea sp. and 100% NPK. Thus, biologically treated OMWW showed promising impacts on plant growth parameters.
Показать больше [+] Меньше [-]Molecular Identification of Some Rhizobium and Serratia Isolates as Potential Producers of Indole-3-Acetic Acid
2023
Sello, Shaimaa | Abdel Razik, Ashraf | Ibrahim, Samir | Elateek, Sawsan
In order to reduce the use of chemical fertilizers, the use of biological inoculants has been increased. Beneficial microorganisms are used to increase crop yields by stimulating plant growth through the production of phytohormones. In the present study, Indole Acetic Acid (IAA) production was analyzed in 18 bacterial isolates with Plant Growth-Promoting (PGP) capabilities; 15 of these isolates were Rhizobium, and three were Serratia. All isolates have been characterized morphologically and biochemically, and their IAA production in the presence of tryptophan, a precursor for IAA biosynthesis, has been evaluated. IAA production was detected using the Salkowski reagent with CT-2200 spectrophotometer at 530 nm. The levels of IAA production varied between the different isolates. The top two IAA producers were selected for genetic identification using 16SrRNA primers (27F and 1492R). One of the Rhizobium isolates (NRC-R2) shared 95% sequence similarity with Rhizobium sp., according to a Blastn search in GenBank and Rhizobium leguminosarum, whereas the Serratia isolate (Ain Shams Center for Genetic Engineering and Biotechnology (ACGEB)-S2 was 99.5% similar to Serratia sp. In the near future, it is possible that these two isolates could serve as biological sources for IAA.
Показать больше [+] Меньше [-]Residue Assessment of Bifenazate, Spirodiclofen and Abamectin in Strawberry Fruits Under Field Conditions
2023
Abdelmaksoud, Eman | Elsayed, Walaa | Elrefai, Shoukry | mahmoud, kadry
The dissipation behavior of three pesticides, bifenazate, spirodiclofen and abamectin was studied in strawberry fruits using a modified QuEChERS extraction technique. The residues of the tested acaricides were determined under field conditions after 1 hour (zero days), 1, 3, 7, 14, and 21 days. The maximum residue limits (MRLs) were 2, 2, and 0.15 mg/kg for bifenazate, spirodiclofen and abamectin, respectively. The strawberry fruits could be used safely after 15 days from bifenazate spraying and after 3 days from spirodiclofen spraying. The concentration of abamectin after 21 days did not reach MRL. The half-life values (t1/2) of bifenazate, spirodiclofen, and abamectin in strawberry fruits were 0.99, 0.86, and 5.7 days, respectively.
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