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Synthesis and Characterization of Nanoparticles for the Control of Aflatoxins and Pathogenic Moulds

Thesis Info

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Author

Muhammad Asif Asgher

Program

PhD

Institute

University of Karachi

City

Karachi

Province

Sindh

Country

Pakistan

Thesis Completing Year

2019

Thesis Completion Status

Completed

Subject

Chemistry

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/11454/1/Muhammad%20Asif%20Asgher%20chemistry%202019.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727455763

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This study provides a novel approach to encounter the well-established global issues of drug-resistant pathogens bacterial/fungal strains and their linked metabolites such as aflatoxins (AFs). Recent advancements have been proposed for incorporation nanoparticles (NPs) in this regards. This study provides a promising solution to control pathogenic moulds and AFs by the utilization of nanotechnology approach and also highlighted the AFs level in various agricultural commodities. A variety of agricultural commodities such as wheat, composite spices and dry fruits/edible nuts were assessed for the AFs determination by HPLC. The iron (Fe), copper (Cu) and silver (Ag) NPs have been synthesized from bio-diversified plants, herbs and spices extracts and chemical reduction method in parallel. These great varieties of NPs are used to control AFs and pathogenic moulds. AFs were detected in 26−77% of samples; the average concentration was found 0.53−4.63 µg/kg with contamination ranged of 0.02−30.11 µg/kg. The spherical shape NPs were successfully synthesized with average particle size ranges from 10−120 nm. Ag-NPs showed a pronounced effect, thereby reducing the growth of methicillin- and vancomycin-resistance Staphylococcus aureus at MIC of 8−16, 32−64 and 128−256 µg/mL for Ag-, Cu- and Fe-NPs, respectively. The growth of aflatoxigenic moulds (Aspergillus) and AFs production was significantly inhibited in presence of 100 µg/mL Ag-NPs, in contrast to Fe- and Cu-NPs. The batch adsorption test for the efficacy of NPs to adsorb aflatoxin B1 (AFB1) indicates that ≥ 95% AFB1 adsorption using 5 mg/mL NPs. Adsorption data was well fitted in Langmuir isotherm model with different adsorption capacities. Kinetics and thermodynamic studies indicates spontaneous adsorption process that is endothermic in nature and follows the pseudo-second order rate equation. The efficiencies of green synthesized NPs were found in the order of: green tea > black tea > clove > neem > datura > jamun > curry leaves > rose > black cumin > mangroves > gum tree > dates. The synthesis of metal NPs using green nanotechnology seems to be the best candidate because it is simple, eco-friendly, costeffective, non-toxic, energy-efficient and considered as alternative to the conventional methods. This study explores the importance of green chemistry, thereby demonstrating for the first time, the successful utilization of green nano synthesis approach for the control of AFs and pathogenic moulds. The NPs could be utilized as alternative antimicrobial agents in medical, agricultural and veterinary fields.
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ڈاکٹر ڈی۔ اے ۔ اسمتھ

ڈاکٹر ڈی ، اے ، اسمتھ

            ماہ گذشتہ میں آکسفرڈ سے ڈاکٹر ڈی، اے، اسمتھ، ال، ڈی کی وفات کی خبر موصول ہوئی ۔ ڈاکٹر موصوف مشرقی علوم سے خاص شغف رکھتے تھے، اور تاریخ ہند کے ایک مستند عالم سمجھے جاتے تھے۔ تقریباً ۱۸۷۰؁ء میں وہ ہندوستان میں ایک سویلین کی حیثیت سے آئے تھے، اور صوبہ متحدہ کے مختلف اضلاع میں مختلف مناصب پر فائز رہ کر کوئی بیس سال ہوئے پنشن لے کر وطن واپس گئے۔ ہندوستان کے سی (۳۰) سالہ قیام میں وہ نادر سکہ جات، کتبات وغیرہ بیش بہا تاریخی مواد فراہم کرتے رہے اور ملازمت سے سبکدوش ہونے کے بعد انھوں نے تاریخ ہند پر متعدد تصانیف شایع کیں، مثلاً اکبر اعظم، راجہ اشوک کا دورِ حکومت، وغیرہ جن میں سے بعض کتابیں ہندوستانی یونیورسٹیوں کے اعلیٰ نصابِ درس میں بھی داخل ہیں، ان کی آخری ضخیم تصنیف ’’آکسفرڈ ہسٹری آف انڈیاــ‘‘ حال ہی میں شایع ہوئی تھی۔ رایل ایشیاٹک سوسائٹی نے تمغوں اور دیگر اعزازات سے ان کی علمی خدمات کا بار بار اعتراف کیا تھا۔ (مارچ ۱۹۲۰ء)

 

التنظيم القانوني للكوتا النسائية وفق دستور جمهورية العراق لعام 2005: دراسة مقارنة

تهدف الدراسة إلى بيان إن كان للكوتا النسائية الدور الحقيقي للحد من ضعف المشاركة السياسية للمرأة في الانتخابات العراقية. وقد أتبعنا في بحثنا منهج الدراسة المقارنة بين نماذج دستورية رئيسة تتمثل في الدستور العراقي لسنة 2005 والدستور المصري لسنة 2014 المعدل والدستور الفرنسي لسنة 1958 مع التركيز على التجربة العراقية في منح المرأة وجود انتخابي، وسبب اختيارنا النموذج المصري والفرنسي لقربها من القانون العراقي كونها تعد مصادر أساسية للقانون العراقي. وأهم ما تم التوصل إليه هو إجراء تعديلات على قوانين الانتخابات البرلمان والمحافظات لإدراج نص يتعلق بالكوتا النسائية بأن تفرد قائمة خاصة بهن أسوة بكوتا الأقليات، يقدمها كل كيان سياسي داخل في الانتخابات، إضافة لقائمته الاعتيادية التي تكون مختلطة نساءً ورجالاً بحسب الترتيب الوارد ذكره في قانون الانتخابات. وتعديل المادة 11 من قانون الأحزاب رقم (36) لسنة 2015بتحديد نسبة (كوتا) لتمثيل النساء في المواقع القيادية للأحزاب لا تقل عن الثلث، لضمان التمكين السياسي للنساء وبناء قدراتهن القيادية والسياسية وتأهيلهن لخوض الحياة السياسية في كافة مراحلها.

Salinity and Extreme Temperature Effects on Sprouting Buds of Sugarcane Saccharum Officinarum L. : Some Histological and Biochemical Studies

Sugarcane shows reduced crop stand under relatively suboptimal conditions, the main reason for this is sensitivity of bud tissue to temperature fluctuations and salinity at sowing time. The aim of these studies was to explore the physiological, developmental and molecular changes occurring in the immature sugarcane buds under heat, cold and salt stresses, and possible role of proline and glycinebetaine in mitigating the changes in a time course manner during sprouting of nodal buds. All the stresses reduced bud fresh and dry weight, led to the generation of H 2 O 2 , reduced the tissue levels of K + and Ca 2+ , but enhanced the synthesis of osmolytes in a time course manner. Heat stress mainly produced oxidative damage and acted as a dehydrative force, whereas cold stress caused oxidative stress and slowed down the physiological activities. Salinity was the most damaging of all the stresses. The main effects of salinity were the accumulation of Na + and Cl - , reduced tissue contents of Ca 2+ and K + and enhanced synthesis of H 2 O 2 in the developing sugarcane bud. As for histological changes, all the stresses delayed and reduced the formation of new bud leaves and their expansion, which was mainly because of reduction in the number and area of mesophyll cells and poor development of vascular bundles. The pretreatment of bud chips with proline and GB effectively reduced stress effects being more effective under heat stress followed by cold stress and the least under salinity stress. As revealed from the correlation studies, although pretreatment with proline and GB appeared to have no direct role in stress tolerance, main effects were the reduced generation of H 2 O 2 , improvement in the K + and Ca 2+ nutrition and further enhancement in the levels of free proline, GB and soluble sugars under heat and cold stress. Under salt stress, the pretreatment reduced Na + and Cl - , in addition to the observed effects under heat and cold stresses. Histological changes revealed that the pretreatment with osmoprotectants increased the mesophyll cell area leading to expansion in the bud leaves and led the development of elaborated vascular tissues. Of the two, GB was more effective than proline for all stress treatments but for different measured variables. Detailed studies on the molecular and metabolic responses indicated the enhanced expression of Asn, dehydrins, LEA and GAPDH genes, stronger accumulation of proline and alanine followed by glycine, glutamic viiiacid and 5-oxo-proline. Among the sugars, sucrose followed by diethylene glycol, fructose, glucose and glycerol, and nucleic acids, adenosine and uracil, as well as organic acids, aconitate, chlorogenate, ribonate_put, quinate, pipecolate, erythronate, GABA, glucoronate, gluconate, glucarate, glucoranate and octadecanoate showed accumulation at all temperature treatments and time periods. HCA and LVL revealed that out of 108 metabolites, chlorogenate, putrescine, octadecanoate, fructose, proline, glycine, sucrose, quinate, trans-aconitate, guanine, GABA and ethanolamine showed greater accumulation under high temperature. In crux, albeit all stresses deterred the transition of bud from immature to mature state, the salinity was the most damaging. In most cases, improvement produced by proline was greater than GB. Heat stress revealed distinct patterns of gene expression and metabolites synthesis. The correlation data showed that pretreatment with the osmoprotectants improved bud growth under stress regimes; the roles are indirect in improved Ca 2+ and K + nutrition and reduced production of H 2 O 2 . Nevertheless, these findings suggest that in low to moderately hot, cool and saline areas sugarcane bud sprouting can be improved by pretreatment of bud chips with the 20 mM levels of proline and GB and requisite crop stand can be achieved