Affiner votre recherche
Résultats 471-480 de 1,443
Partial Gap-Filling of the Nile Tilapia (Oreochromis niloticus) Draft Genome
2023
Hala Zoghly | Mohamed Rashed | Mahmoud Magdy
Nile tilapia is a freshwater fish of African origin, with productive and economic characteristics affecting global fish markets. The Oreochromis niloticus reference genome has a diploid set of 22 linkage groups (LGs) in addition to ungrouped sequences. A total of 42,622 genes have been identified, but 550 genomic gaps may include more. Our study focused on some of these genomic gaps, where appropriate primers were designed and then multiplied through the polymerase chain reaction (PCR) technique. From local samples, DNA was extracted and amplified with the new primers. Successful amplicons were sequenced and annotated using available bioinformatics tools. Five assessed sequences were annotated, of which three were newly predicted in O. niloticus, as mucin 1-like, and KLR genes, and SATB region. The other two sequences belonged to grid2 and trpm7 which were previously predicted. Although individual attempts to identify genomic gaps are not feasible in filling the large lack of information on the Nile tilapia genome, a good number and valuable new information has been reached. However, the following plan showed many technical problems, more time, effort and cost that could be avoided by suggesting the application of another technique, such as whole-genome sequencing, mapping, and assembly.
Afficher plus [+] Moins [-]Effect of Rumen-Protected Choline Supplementation on Growth Performance of Fattening Calves
2023
Abdelrahman Amin | Ahmed Marwan | Fouad Abdelaziz | Nasr Elbordiny
This study aimed to evaluate the influence of choline chloride supplementation on the growth performance of feedlot calves. Thirty-two crossbred calves with a mean initial body weight of 305.71±4.09 Kg were divided into three groups of 10, 11 and 11 animals, randomly. The animals were distributed to one of three dietary treatments, control, choline15 and choline 30 (the rations supplemented with 0, 15 and 30 g choline chloride, respectively). The animals were fed on concentrate feed at a rate of about 2.15% of their live body weight and rice straw open access. Supplementing animal ration with choline chloride did not significantly affect all nutrients' digestibility and feeding value. The animals supplemented with 30 g choline chloride recorded significantly higher (P=0.037) total serum protein concentration compared to the other groups. The group received a ration supplemented with 30 g of choline chloride and recorded significantly higher final weight, total gain, and mean daily gain. Data showed significant improvement in TDN, CP and DCP conversion for the animal received ration supplemented with 30 g choline chloride compared to the control group. In conclusion, supplementing fattening calves' ration with rumen-protected choline could improve average daily gain and feed conversion.
Afficher plus [+] Moins [-]Molecular Genetic Studies on Honeybees in Response to Some Environmental Stresses
2023
Rehab Mohamed | Naglaa Ebeed | Khalid Fahmy | Naima Alsenosy | Sawsan Abdelmegeed
The honeybee, Apis mellifera, is a widespread pollinator insect. Colony collapse disorder (CCD) has recently caused a significant decline in honeybee numbers worldwide. The beekeeping industry, agriculture, and world biodiversity are threatened by the honeybee population decline. We examined the mRNA levels of heat shock protein gene 60 (hsp60), acetylcholinesterase 1, and acetylcholinesterase 2, as biomolecular markers of the insect response to three separate forms of environmental stress, including high temperature, low temperature, and insecticide. The obtained results indicated increased levels of hsp60 and acetylcholinesterase 2 after the exposure of worker bees to temperatures of 17, 32, and 40°C for one hour, as well as exposure to a low dose of pesticide for 24 h ingestion of imidacloprid solution (2 ppm); meanwhile, acetylcholinesterase 1 showed remarkable expression decrease under heat and cold stresses but increased under pesticide treatment. The responses of honeybees to hsp60, acetylcholinesterase 1, and acetylcholinesterase 2 are diverse and very specific to various stimuli. According to this research, the distinct expression profiles of hsp60 and acetylcholinesterase 2 can serve as useful instruments for tracking honeybees' vulnerability to varied environmental effects. Due to its insufficient responsiveness, acetylcholinesterase 1 expression is not permitted for use as a biomarker.
Afficher plus [+] Moins [-]Harvesting Microalgae by Chitosan as Sustainable Biopolymer
2023
Ola Obyd | Ayman Abou Hadid | Shawky Selim | Tarek El-Arabi
This study aimed to use the organic polymer, chitosan, as a flocculant for harvesting microalgae Chlorella. sp. Various polymer concentrations were tested. Within three min, 50 mg/L of chitosan showed the highest efficiency (98.9±0.5%), at pH 6.3, while the lowest efficiency (86.7±0.5%) was observed at pH 7.5. Harvesting efficiency in this study was chitosan concentration dependent. The present study showed that chitosan can be a promising and sustainable solution as an organic source and environmentally friendly flocculant. Additionally, it has excellent harvest productivity and requires minimum effort for quick outcomes.
Afficher plus [+] Moins [-]Increasing of Amylopectin in Tetraploid Potato Desiree Cultivar (Solanum tuberosum L.) Via CRISPR/Cas9
2023
Nermin Ali | Mohamed Abdel-Salam | aiman hanfy | Haytham Abd-Elhalim | Nouh Ahmed | Emad Metry
Potato tuber starch characteristic is influenced by the ratio of amylose to amylopectin, which is affected by the granule-bound starch synthase (GBSS) gene. GBSS gene expression was decreased in the leaves of the Desiree potato variety utilizing genome editing using CRISPR-Cas9. Constructs encoding Cas9 gene and sgRNAs targeting GBSS gene were inserted into plant leaves using Agrobacterium-mediated transformation delivery. The results obtained lines with mutations in GBSS genes accounting for 21% of regenerated shoots. The identification of mutations within one base pair of the used guide sequence provided further evidence of the considerable similarity between the target region around the protospacer adjacent motif (PAM) position and the used guide sequence. Transforming DNA into potato leaves produced mutants that lacked the Cas9 gene. Using microscopic inspection of iodine-stained starch granules, the increase of amylopectin in the starch granules of editing potato tubers was evaluated.
Afficher plus [+] Moins [-]Element Composition and Toxicity of Seaweed Algae (Ulva lactuca, Laurencia obtuse and Padina pavonica) Toward Shrimp
2022
Ahmed Muhammad | Ibrahim Hassan | Manar Tawfeek | Hayam Ahmed Ibrahim
This study examined the macro and trace element contents as well as the cytotoxicity of Laurencia obtusa, Ulva lactuca, and Padina pavonica algae collected from the Mediterranean coast of Egypt (Alexandria coast). The results indicated that the seaweed samples contained high concentrations of Ca, Cl, Mg, K, Na, P and Fe. The Cu and Zn contents of the algae were in the ranges of 0.39-0.95 mg/100 g dw and 0.11-0.49 mg/100 g dw respectively. Fresh red algae contained the highest level of Zn and Cu, whereas the iodine level was 1.52, 1.27 and 1.01 mg/100g in fresh each of Padina pavonica, Laurencia obtuse and Ulva lactuca respectively. Fresh red, fresh green, dry green, dry red, in addition to fresh and dried brown algae had maximum lead (Pb) levels of 0.16, 0.14, 0.13, 0.12, 0.04 and 0.02 g/100 g respectively. Fresh red algae contained the highest Cd and Mn levels, whereas dried brown algae exhibited the lowest Cd and Mn concentrations. Different extracts of fresh and dried brown algae exhibited significant larvicidal activity against brine shrimp. LC50 values indicated that dry samples were more cytotoxic than fresh samples.
Afficher plus [+] Moins [-]Effect of Different Levels of Salinity and Anti-Transpiration on the Growth Characteristics and Chemical Composition of Panicum maximum (Jacq.)
2022
Adel El Wardany | Nasr Elbordiny | Ramadan Abdrabou | Adel Bakr | Yasser Abdelkareem
This study aimed to determine the effect of different salinity and anti-transpiration levels on the growth and biochemical composition of Panicum maximum plants (Guinea grass) during the spring and summer of 2020. Two different anti-transpiration treatments [molasses (sugarcane) (5 mL/L), kaolin (50 g/L) and control] and three salinity levels (S1 well water as the control and salinity S2 2000 ppm; S3 4000 ppm, S4 6000 ppm) were used in 12 treatments in 72 pots (3 anti-transpiration treatments × 4 salinity treatments × 6 replicates); a randomized complete design was used. Results revealed that the plants achieved the highest plant height (123.77 cm) and dry weight (521.87 g/m2) with kaolin and no salt addition treatment during summer. A higher percentage of proteins and carbohydrates were found in spring than in summer, but there was no significant difference in the salinity levels. A high percentage of ash and fiber contents was also observed during summer, with no significant differences between the anti-transpiration treatments. It could be concluded that P. maximum, as one of the most important fodder crops, could be cultivated in marginal lands, especially during the summer season.
Afficher plus [+] Moins [-]Impacts of Natural and Supplementary Foods on Some Biochemical Activities in the Bodies of Honeybee Workers
2022
Sobhia Sayed | Mohamed Elsherif | Adel Mahmoud Basuony | Naglaa Ghazala
The experiments were conducted during seasons (summer, au-tumn, winter, and spring) 2020–2021 to study the activities of invertase, adenosine triphosphatase (ATPase), and alkaline phosphatase (AlkP) as well as the determination of total proteins. These activities were determined in the bodies of adult honeybee worker, Apis mellifera, (house and forager bees) after feeding on three different diet groups (A) pollen cake, (B) supplementary diet and (C) control group during the four seasons. Group (A) received 50 g pollen cake + 250 ml honey syrup (2 honey: 1 water)/colony/three-day intervals, group (B) received 50 g Brewer’s yeast chickpea cake fortified with 4.2% pollen + 250 ml sugar syrup (2 sugar: 1 water) while group (C) received 250 ml sugar syrup (1 sugar: 1 water) only. Results indicated that the highest increase in total proteins was found in group B during the autumn season with house bees. Invertase activity was high in group A during the summer season with forager bees. The highest ATPase activity was observed in group B during the spring season with house bees, whereas the highest AlkP activities were found in group A during the autumn season with house bees.
Afficher plus [+] Moins [-]Improvement of Growth and Productivity of Mango Trees Using Some Growth Stimulants under Salinity Conditions
2022
Fatma Abdalla | Hassan Elwakeel | Noha Mansour | Sabry Osman
A study was carried out in a mango orchard on reclaimed land for two seasons in 2019 and 2020. The experiment was implemented on fifteen years old mango trees “Fagri Kalan” budded on seedling mango rootstock and planted at 4 × 4 m. This experiment involved two soil growth stimulants (K humate, magnetite) and foliar application with cobalt. The experiment involved two factors, the first one was soil application with K humate by two levels (50 and 100 g/tree/year) and magnetite by two levels (250 and 500 g/tree /year) plus control, whereas the second factor was a foliar application with Co as cobalt sulfate by three levels (0, 15, and 30 ppm Co). The experiment was carried out in a factorial experiment in split plot design with three replicates whereas each replicate was represented by two trees. Result indicated that soil application with K humate at 100 g/tree followed by magnetite at 250 g/tree or foliar application with Co at 15 ppm alone or the combination between (K humate at 100 g/tree and cobalt at 15 ppm) gave the highest values of yield/tree, fruit weight, TSS, reducing sugars, leaf N, P, K, and Fe content of “Fagri Kalan” mango trees grown under salinity conditions.
Afficher plus [+] Moins [-]Utilization of Agro-Wastes for Bioethanol Production
2022
Sodaf Maan | Abdelwahab Abdelhafez | Asmaa Ahmed | Enas Hassan
Four agro-wastes were evaluated as substrates for bioethanol production. Seven of the pioneer isolates in the production of cellulase, xylanase and laccase enzymes were selected for soluble sugar and bioethanol production. The highest level of soluble sugar was produced on sugar beet pulp followed by corn cobs. The experimental design included using soybean okara and sesame husk as nitrogen sources added to the production medium. Extraordinary soluble sugar yields were obtained on sugar beet pulp or corn cobs in combination with soybean okara or sesame husk at the concentration of (0.3%) of either. Different concentrations of corn cobs or sugar beet (5, 10, 15, g/100 m medium) were mixed with optimal concentrations of nitrogen sources. Results showed that 10 g of sugar beet or corn cobs achieved the highest soluble sugar yield. The efficiency of four strains of S. cerevisiae for bioethanol production was investigated, S.cerevisiae (AUMC 14720) recorded the highest level of bioethanol on fermentable fungal broth after four days at 30°C.
Afficher plus [+] Moins [-]