NBU-IR

University Library

University of North Bengal

Our Institutional Repository is dedicated for storing, organizing, safeguarding, and granting access to the increasing volume of digital resources generated from University's research, educational, and administrative endeavors.

Thesis

NBU Journals

Rare Doc.

Faculty Pub.

Slide Image
Slide Image
Slide Image
 

Communities in NBU-IR

Select a community to browse its collections.

Recent Submissions

No Thumbnail Available
ItemOpen Access
Bharateli nepali kathama hasyatatwako prayog भारतेली नेपाली कथामा हस्यतात्वको प्रयोग गुरुङ
(University of North Bengal, 2023) Gurung गुरुङ , Sunil सुनिल; Ghatani घतानी, Krishnaraj कृष्णराज
No Thumbnail Available
ItemOpen Access
Studies on genetic variability and distribution of begomoviruses affecting economically important crops of sub-himalayan plains of North-East India
(University of North Bengal, 2023) Karmakar, Arup; Biswas, Kajal Kumar
Diseases caused by viruses are responsible for poor crop yield in several vegetable crops. Several million rupees are lost worldwide due to infection of our crops by viruses. Begomoviruses are the most devastating plant pathogens that causes high amount of crop loss every year in India. Several vegetable crops are cultivated in sub-Himalayan West Bengal and Assam. Due to yearlong conducive atmosphere production of the vegetable crops are also popular to the local farmers. The present work entitled “Studies on genetic variability and distribution of begomoviruses affecting economically important crops of Sub- Himalayan plains of North-east India” consists of the following objectives such as i) Identification of begomoviruses infecting economically important crops of sub-Himalayan plains of North-east India using Polymerase chain reaction (PCR) and Rolling circle amplification. ii) Sequence analysis and determination of variability among begomoviruses and their strains using bioinformatics tools. iii) Eco-friendly management of important Begomovirus diseases using botanicals. To know the begomoviral diseases of the present study area, a survey was carried. Around 20-75% begomoviral disease incidences have been found in some vegetable crops. Ten important crops of the present study area are tomato, cucumber, potato, kenaf, pointed gourd, papaya, loofah, pumpkin, chilli and ladies finger. Begomoviral symptoms were found in all the ten crops, resulting to significant crop loss. Major symptoms observed were mild to severe yellow mosaic, upward leaf curling, leaf rolling, stunted growth, leaf deformation, networking of yellow veins, followed by thickening of veins and vein lets, puckering, stunting of whole plant and reduced fruit yield. Altogether 55 samples were tested through PCR using different primer sets. Among the 55 samples, 17 samples were positive for begomoviruses. Out of the 17 samples eight were from tomato, seven were from cucumber; one was from kenaf and one was from pumpkin plants. Out of the 16 Begomovirus isolates of the present study, nine were identified as Tomato leaf curl New Delhi virus (ToLCNDV), two were identified as Radish leaf curl virus (RaLCV), two were identified as Papaya leaf curl virus (PaLCuV), one was identified as Tomato leaf curl Karnataka virus (ToLCKV), one was identified as Tobacco curly shoot virus (TbCSV) and one was identified as Ageratum enation virus (AEV). Among the ToLCNDV isolates, three were detected in tomato (Accssion Nos. KX108860, KX817297and MZ516898), five in cucumber (Accssion Nos. KY783746, KY807530, MG721011, MG721012 and MG721013) and one in pumpkin (Accssion No. MG721010). Two isolates of tomato of the present study were found to be Radish leaf curl virus [Accession no. MK333456] as they showed 97% sequence similarity with other RaLCV sequences previously submitted in GenBank. Based on 94-96% sequence similarities following results were found: i) Papaya leaf curl virus detected from tomato (Accession No.MZ516896) and cucumber plants (Accession No. MK333457). ii) Tobacco curly shoot virus was also detected from cucumber (Accession No. MG721014) plants iii) one tomato sample was found to contain Tomato leaf curl Karnataka virus (Accession No. KX108859) iv) One Begomovirus species Ageratum enation virus [Accession no. MZ516897] infecting tomato was identified. That AEV showed 95% sequence similarity with the other AEV of the GenBank. In this study, infected leaves of selected plants like tomato, cucumber and kenaf were used for Begomovirus detection through Rolling Circle Amplification (RCA). High molecular weight DNA obtained by RCA of the infected sample was visible in 1% agarose gel under UV-transilluminator, indicating the amplification of circular DNA. RCA product (5 μl) was digested with a number of different restriction enzymes to select an enzyme with a single restriction site in the DNA components. XbaI and BamHI were found to have a single site in both DNA-A and DNA-B component. In the HindIII digested sample two bands of 2.7kb and 1.4 kb were found. In the Pst digested product, three bands of 2.74kb, 1.4kb and 1.45kb were found. In the EcoRI digested sample, two bands of 2.74 kb and 1.4kb were found. The band 2.7kb probably indicate the presence of whole genome of Begomovirus either DNA- A or DNA-B, and the band of about 1.45 kb probably indicate the presence of beta-satellite or alpha-satellite until sequenced. The amplified fragment of 2.74kb were purified and ligated in to pGEM-3Z vector which was also digested by the same enzyme XbaI and cloned according to manufactures instruction. After transformation in to DH5α strain of E.coli, white colonies were screened for the gene of interest by PCR and restriction digestion with XbaI. Positive PCR white colony was selected for sequencing. Three isolates (To/Guw, Cu/Khr and K/Blg) were found positive following RCA and RFLP. Those three isolates produced distinct bands of ~2.7kb and ~1.4kb. The RCA product was subjected to PCR by β satellite specific primer and the amplicons were found to the betasatellite (after cloning and sequencing). Out of the two positive samples, one was identified as Tomato leaf curl betasatellite (ToLCB) infecting tomato (Accession No. MK333455) as it showed 96% sequence similarity with ToLCB. Another one was identified as Cotton leaf curl Multan betasatellite (CLCuMB) infecting Kenaf plants (Accession No. MK358823), which showed 98% sequence similarity with CLCuMB upon BLASTn analysis. The recombination analysis by RDP4 showed that the isolate GUW-01 (Tomato leaf curl betasatellite; Accession No. MK333455) was a recombinant having major parent Tomato yellow leaf curl Thailand betasatellite (TYLCTHB, Accession No.GU058327), and minor parent TYLCTHB (Accession No. GU058324) infecting tomato in China. This suggests that the ToLCB isolate GUW-01 (Accession No. MK333455) may have derived from recombination and it contains sequences derived from TYLCTHB (Accession No. GU058324). The sequences of AEV infecting tomato were clustered together with other tomato infecting AEV isolates in the phylogenetic analysis. PaLCV isolates of the present study clustered with PaLCV infecting Carica papaya whereas PaLCV from other hosts showed separate clusters. RaLCV isolates infecting tomato of the present study showed close relationship among them and clustered with tobacco infecting RaLCV isolate. Phylogenetic analysis of TbCSV isolate infecting cucumber showed that the isolate formed separate small cluster with Phaseolus vulgaris infecting TbCSV whereas the isolates infecting other host formed different cluster. Tomato infecting ToLCKV of the present study clustered with tomato infecting ToLCKV of GenBank and showed close relationship with tomato infecting isolates found worldwide. Phylogenetic analysis of the present nine ToLCNDV sequences along with other ToLCNDV sequences obtained from public database revealed close relationship among them and clustered together. Pumpkin-infecting isolate of the present study showed close relationship with other pumpkin-infecting ToLCNDV isolates. Cucumberinfecting isolates was also clustered together with other cucumber-infecting ToLCNDV isolates except one isolate which positioned alone. But tomato infecting isolates clustered with cucumber-infecting In phylogenetic analysis Cotton leaf curl Multan betasatellite (CLCuMuB) isolate showed close relationship and clustered together with other CLCuMuB isolates whereas Tomato leaf curl betasatellite (ToLCB) isolate showed close relationship with Tobacco curly shoot betasatellite (Accession No. KX857135) and also clustered together with that isolate. In the present study, four enzymes (peroxidise, β-1,3-glucanase, Polyphenol oxidase and PAL) activity was studied following application of the chemical inducers. BABA treated and BABA treated-inoculated plants showed highest peroxidase activities followed by AABA treated and AABA treated-inoculated plants. Highest increase in β-1,3-glucanase activity was found after 12 days of treatment in the GABA treated-ToLCNDV inoculated plants followed by BTH treated-ToLCNDV inoculated plants as compared to the control plants. Polyphenol oxidase activity was also increased in all treated plants except BABA treated plants. Among the inducer treated plants, BABA treated plants showed maximum PAL activity. GABA and BTH treated plants showed comparatively less PAL activity. Among the „plant extract-treated‟ plants, P. betel treated plants showed Maximum peroxidase enzyme activity followed by A. indica treated plants. Treated-inoculated plants also showed significant increase of enzyme activity. Among the experimental plants, A. indica leaf extracts treatedinoculated plants showed highest enzyme activity followed by C. sinensis treated-inoculated plants. Botanical plant extracts also increased the level of β-1,3-glucanase activity in treated plants. Among the treated and treatedinoculated plants, C. sinensis treated and treated-inoculated plants showed maximum enzyme activity followed by P. betel treated and treated-inoculated plants. PAL enzyme activity was also studied after exogenous application of the plant leaf extracts. Here in this study A. indica leaf extract treated and treated-inoculated plants showed highest enzyme activity than the control. Piper betel treated-inoculated plants also showed an increased level of PAL activity. PPO activity was also significantly increased in the plant extract treated and treated-inoculated experimental plants of this study. B. diffusa treated and treated-inoculated plants showed highest enzyme activity followed by P. betel treated and treated-inoculated plants. Some of the new findings are (i) New host (tomato) infected by Radish leaf curl virus, (ii) New host (Cucumber) infected by Papaya leaf curl virus and Tobacco curly shoot virus (iii) Tomato leaf curl New Delhi virus infecting cucumber is being reported for the first time from this region and (iv) betasatellites of begomovirus isolate like Tomato leaf curl betasatellite infecting tomato plants along with their recombination events. Genetic variability of the isolates was also studied. Finally management of the begomoviral disease caused by Tomato leaf curl New Delhi virus has been done by four chemical inducers and five botanical leaf extracts. Some of the chemical and botanical inducers showed significant disease reduction.
Thumbnail Image
ItemOpen Access
Food security and poverty : a case study of tea gardens in North Bengal
(University of North Bengal, 2023) Chakraborty, Abhijit; Roy Mukherjee, Sanchari
Food Security has attracted a lot of interest in the economic literature, especially in recent years1. One of the ways to measure poverty is food security. Since minimum calorie intake is a basis for measuring poverty. Food security on the other hand is defined as “Food security, at the individual, household, national, regional and global levels is achieved when all people, at all times, have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life’’2. Thus, if enough food is not available, we would call a certain population food insecure. On the other hand, out of the various measures of poverty the basic needs approach tries to identify the nutritional requirement as per person calorie requirement and then convert it into monetary terms to determine a poverty line(Atkinson 2019). The other method is the capability approach as proposed by Amartya Sen which tries to explain poverty in terms of basic capabilities or functioning. The basic needs approach is an old theory. The poverty literature also identifies the measurement issues under two broad heads one is the direct method and the other is the indirect method. The direct method takes into consideration the shortfall in minimum calorie requirement, whereas the indirect method takes into consideration the income required to satisfy the minimum calorie required3. The minimum calories required for basic sustenance are used as a method for determining poverty lines in many countries4. There is also a vast literature which has tried to identify the relation between food security and poverty(Kakwani and Son 2016). The interest by economists in the hypothesis of calorie intake and its effect on income is central to the efficiency wage hypothesis, proposed by Leibenstein (Leibenstein 1957). The seminal work states that the efficiency of work depends on wages, which comes from nutrition (Dawson, Tiffin 1998) and thereby nutrition will play a major role in the country. Thus, we can claim there is a relationship between poverty and food security. In India, the poverty line is determined using the minimum calorie approach and therefore we state that people falling below a certain calorie norm are considered to be food insecure. The required dietary allowance or the recommended calorie at the poverty line is usually taken from the RDA proposed by ICMR. We use the direct method to determine the extent of poverty and thus food security in our surveyed population. The research hypothesis we propose are: Research Hypothesis • Poverty and food security are related, poverty leads to food insecurity and food insecurity leads to poverty. • Tea gardens of North Bengal exhibit marked regional disparities in terms of food security and poverty • PDS has helped to address the problems of Food Insecurity in the Tea Gardens of North Bengal. • Other determinants of Food Security show that there exists food insecurity in Tea Plantations Research Questions: • What is the present socio-economic status of the Tea Plantation workers in the selected gardens? • What is the role of the public distribution system in India in mitigating food security? • How has the PDS evolved in the tea gardens? • Is Poverty and Food Security related? • Are the people in Tea Gardens suffering from undernourishment? • What are the other determinants of Food Security? We use household-level data to test the hypothesis. We also determined the other factors that might affect food security. We find evidence that food security and poverty are indeed related. Results also show high incidence of undernutrition among the Tea plantations, which is a core indicator of food security. Our analysis suggests among the various determinants of food security, the most important are household size and education.
Thumbnail Image
ItemOpen Access
Exploration of the chelation property of few newly designed (N,O)-type schiff base ligands with d-block metals and bio-oxidase activities of their synthetic coordination compounds
(University of North Bengal, 2023) Mahato, Shreya; Biswas, Bhaskar
This dissertation comprises a total of seven chapters. Chapter I consists of a concise introduction to the design, foundation, and applications of the coordination compounds based on synthetic and commercially available ligands and the applicability of the present work in the recent trends of scientific development. Chapter II represents the synthesis, X-ray structural analysis, supramolecular architectures, and oxidative coupling of 2-aminophenol of a copper(II) complex, [Cu(L1)](H2O) (1) containing a previously reported Schiff base, H2L1 = 2,2'-((1,2- phenylenebis(azanylylidene))bis(methanylylidene))diphenol. The analysis of the crystal structure indicates that the Cu(II) centre adopts a square planar coordination geometry within the R3̅ space group. Furthermore, the aqua molecule located nearby actively participates in significant intermolecular hydrogen bonding, resulting in the formation of a water-mediated dimeric unit of the Cu(II) complex. The Hirshfeld surface analysis suggests that C−H…O and O−H…O types of hydrogen bonding, as well as π⋯π interactions play a crucial role. The catalytic properties of complex 1 were assessed for the oxidative dimerization of 2-aminophenol (2-AP) in methanol, revealing high catalytic efficiency with a kcat/KM value of 2.14×105. Additionally, studies utilizing mass spectrometry confirmed that the catalytic process involves the formation of an enzymesubstrate adduct in the solution phase. Chapter III represents the synthesis, X-ray structural analysis, Hirshfeld surface analysis, oxidative dimerization of 2-aminophenol and antibacterial activity of a newly designed copper(II)-Schiff base complex, [Cu(L2)2] (2), [Schiff base (HL2) = 2-(2- methoxybenzylideneamino)phenol]. X-ray analysis of complex 2 reveals that the Cu(II) complex forms crystals in a cubic crystal system with the Ia3̅ d space group. In its crystalline phase, the Cu(II) centre adopts a unique tetragonal bipyramidal geometry. Complex 2 has been tested for its phenaxozinone synthase activity in acetonitrile, mimicking biological systems, and demonstrated significant catalytic activity with a high turnover number of 536.4 h−1. Electrochemical analysis of complex 2 showed the appearance of two additional peaks at −0.15 and 0.46 V in the presence of 2-AP. This suggests the formation of AP−/AP•− and AP•−/IQ redox couples in the solution. The presence of the iminobenzosemiquinone radical at g = 2.057 was confirmed in the reaction mixture through electron paramagnetic resonance, indicating its role as the driving force for the oxidative dimerization of 2-AP. The ESI-mass spectrum exhibited a peak at m/z 624.81 for complex 2 in the presence of 2-AP, confirming that the catalytic oxidation proceeds through the formation of an enzyme-substrate adduct. Furthermore, complex 2 showed potential antibacterial properties against pathogenic bacterial species such as Staphylococcus aureus, Enterococcus, and Klebsiella pneumonia. Scanning electron microscope studies provided evidence that the antibacterial activity is attributed to the destruction of the bacterial cell membrane. Chapter IV represents the synthesis, crystal structure, supramolecular architecture, 4- methylcatechol oxidation, and bactericidal activity of an interesting zinc(II)-Schiff base complex, [Zn(L2)2Cl2] (3), [Schiff base (HL2) = 2-(2- methoxybenzylideneamino)phenol]. The analysis of the crystal structure of complex 3 indicates that the zinc centre is present in a distorted tetrahedral arrangement. The Schiff base molecule adopts three donor centres, but it becomes protonated and exists as a zwitterionic form, acting as a monodentate coordinator towards zinc. Complex 3 has been studied for its ability to catalyse the biomimetic oxidation of 4-methylcatechol (4-MC) in methanol, and it demonstrates high efficacy with a good turnover number of 1.45 × 103 h−1. Various techniques such as electrochemical studies and electron paramagnetic resonance analysis have been employed to investigate the behaviour of complex 3 in the presence of 4-MC. The results confirm that the catalytic reaction proceeds through enzyme-substrate binding, and the generation of radicals during the catalytic process drives the oxidation of 4-MC. Additionally, an antibacterial study has been conducted against several clinical pathogens including Bacillus sp, Enterococcus, and E. coli. To assess the antimicrobial properties of complex 3, scanning electron microscope and EDX analysis were performed on the pathogens treated with a low dosage of the complex. The results reveal the destruction of the bacterial cell membrane in the selected zone of inhibition area, with a zinc occurrence of 1.44%. This finding holds significant promise for the development of future antibacterial agents. Chapter V represents the synthesis and crystal structure of a palladium(II) complex [(κ4- {1,2-C6H4(N=CH−C6H4O)2}Pd] (4) supported by a dianionic salen ligand [1,2- C6H4(N=CH−C6H4O)2]2− (H2L1) was synthesized and used as a molecular pre-catalyst in the hydroboration of aldehydes and ketones. Complex 4 was evaluated as an effective catalyst in the hydroboration of aldehydes and ketones using pinacolborane (HBpin). This process yielded boronate esters in exceptional yields at room temperature without the need for solvents. Furthermore, complex 4 demonstrated its competence as a catalyst in the reductive amination of aldehydes with HBpin and primary amines. This reaction occurred under mild and solvent-free conditions, resulting in a high yield (up to 97%) of secondary amines. Both methodologies exhibited remarkable conversion rates, excellent selectivity, and a wide range of applicability, accommodating electron-withdrawing, electron-donating, and heterocyclic substituents. A computational investigation utilizing density functional theory (DFT) elucidated the reaction mechanism behind the complex 4-catalyzed hydroboration of carbonyl compounds in the presence of HBpin. Additionally, the protocols unveiled the dual functionality of HBpin in facilitating the hydroboration reaction. Chapter VI represents the design and preparation of metal complex salts of the novel hybrid d-f block type, [Cu(bpy)2]2[Ce(NO3)6]2 (5), [Cu(phen)2(NO3)]2[Ce(NO3)6](HNO3) (6), [Zn(bpy)2(NO3)][ClO4] (7), and [Zn(phen)2(NO3)]2 [Ce(NO3)6] (8); [bpy = 2,2'- bipyridine; phen = 1,10-phenanthroline]. X-ray analysis of the structures of 5 and 6 reveals that the copper(II) centres in the cationic complex units have highly distorted tetrahedral and rare bicapped square pyramidal coordination geometries, respectively. Similarly, 7 and 8 exhibits rare bicapped square pyramidal geometry for their zinc(II) ions, while 5, 6, and 8 contain cerium(IV) ions arranged in a dodecahedral geometry. Studying the supramolecular interactions, it is observed that intermolecular O⋯H and O⋯π short contacts contribute to binding the complex units in 5. In contrast, complex salt 6 demonstrates predominantly π⋯π interactions, along with O⋯H and O⋯π short contacts, which facilitate binding among the complex units. To investigate the chargetransport phenomenon, we utilized complex salts (5-8) to construct Schottky devices. The carrier mobilities (μ) for salts 5-8 were determined as 1.76 × 10−6, 9.02 × 10−6, 1.86× 10−8, and 4.31 × 10−8 m2 V−1 s−1, respectively, with corresponding transit times (τ) of 439, 85, 4.17 × 103, and 1.79 × 103 ns. These results indicate that complex salt 6 exhibits the highest transport properties among all the complex salts. Analysing the charge-transport properties from a crystal engineering perspective, the superior performance of 6 can be attributed to its predominant π⋯π interactions. Overall, the synthesis of these novel complex salts, along with their physicochemical properties and charge-transport applications, holds significant promise for the development of new crystalline materials with intelligent functionalities. Chapter VII outlines an overview of the progress made thus far and identifies prospective avenues for future research.
Thumbnail Image
ItemOpen Access