122 research outputs found
Nanoecology: Exploring Engineered Nanoparticles’ Impact on Soil Ecosystem Health and Biodiversity
No full textNANOTECHNOLOGY is a growing field that explores the interactions between engineered nanoparticles and ecosystems, with a focus on soil health and biodiversity. Engineered nanoparticles are intentionally designed at the nanoscale and offer unique properties and diverse applications, making them increasingly prevalent in consumer products and industrial processes.
However, their release into the environment has raised concerns about potential ecological consequences, particularly their impacts on soil health. Studies have shown that engineered nanoparticles can have complex effects on soil microbial communities and nutrient cycling, with responses ranging from positive to adverse. Additionally, their ability to be absorbed and translocated
by plants brings upon questions about their potential bioaccumulation in food chains and their effects on higher trophic levels. Understanding these intricate interactions is crucial for developing sustainable nanotechnology applications that can benefit agriculture and environmental remediation without compromising the ecosystem health. Nanoecology is an emerging field that requires attention to ethical and regulatory considerations in the use of nanomaterials. To ensure that these advanced technologies
contribute positively to the ecosystem, researchers and policymakers must address these aspects. By understanding the complex interactions between nanoparticles and ecosystems, nanoecology offers the potential for innovative solutions that promote sustainable coexistence between nanotechnology and the natural world. This study specifically focuses on the relationship between engineered nanoparticles and soil health profiling. It provides a concise overview of this relationship, emphasizing the
importance of responsible nanoparticle use. Additionally, the study highlights the need for monitoring soil health in soils contaminated with nanoparticles. Overall, this research underscores the significance of considering ethical and regulatory factors in the use of nanomaterials. It also emphasizes the importance of understanding the impact of nanoparticles on soil health and the need for responsible practices in their application
Synthetic Gene Complementation to Determine Off-Target Silencing
No full textRNA interference (RNAi) is a conserved mechanism in a wide range of eukaryotes. Introduction of synthetic dsRNA could specifically target suppression of a gene or could result in off-target silencing of another gene due to sequence similarity. To verify if the observed phenotype in an RNAi transgenic line is due to silencing of a specific gene or if it is due to another nontarget gene, a synthetic gene complementation approach could be used. Synthetic gene complementation described in this method uses the technology of synthesizing a variant of a native gene (used in RNAi silencing) to maximize the difference in DNA sequences while coding for the exact same amino acids as the original native gene. This is achieved through the use of alternate codons. The new variant gene is expressed in the original RNAi transgenic lines and analyzed for complementation of the RNAi phenotype. Complementation of the RNAi-induced phenotype will indicate gene-specific silencing and not off-target silencing
Structural Studies On Enzymes From Salmonella Typhimurium Involved In Propionate Metabolism: Biodegradative Threonine Deaminase, Propionate Kinase And 2-Methylisocitrate Lyase
No full textI formally joined Prof. M. R. N. Murthy’s laboratory at the Molecular Biophysics
Unit, Indian institute of Science, on 1st August 2001. During that time, the interest in the laboratory was mainly focused on structural studies on a number of capsid mutants of two plant viruses, sesbania mosaic virus and physalis mottle virus, to gain an insight into the virus structure and its assembly. Besides these two projects, there were a few other collaborative projects running in the lab at that time such as NIa protease from pepper vein banding virus and diaminopropionate ammonia lyase from Escherichia coli with Prof. H. S. Savithri, triosephosphate isomerase from Plasmodium falciparum with Prof. P. Balaram and Prof. H. Balaram and a DNA binding protein (TP2) with Prof. M. R. S. Rao. During my first semester, along with my course work, I was assigned to make an
attempt to purify and crystallize recombinant NIa protease and TP2 protein. I started with NIa protease which could be purified using one step Ni-NTA affinity column chromatography. Although the expression and protein yield were reasonably good, protein precipitated with in a couple of hours after purification. Attempts were made to prevent the precipitation of the purified enzyme and towards this end we were successful to some extent. However, during crystallization trials most of the crystallization drops precipitated completely even at low protein oncentration. TP2 protein was purified using three-step chromatographic techniques by one of the project assistant in Prof. M. R. S. Rao’s laboratory. Because of low expression level and three step purification protocol, protein yield was not good enough for complete crystallization screening. Hits obtained from our initial screening could not be confirmed because of low protein yield as well as batch to batch variation. My attempts to crystallize these two proteins remained unsuccessful but in due course I had learnt a great deal about the tips and tricks of expression, purification and mainly crystallization. To overcome the problems faced with these two proteins, we decided to make some changes in the gene construct and try different expression systems.
By this time (beginning of 2002), I had finished my first semester and a major
part of the course work, so we decided to start a new project focusing on some of the
unknown enzymes from a metabolic pathway. Dr. Parthasarathy, who had finished his
Ph. D. from the lab, helped me in literature work and in finding targets for structural
studies. Finally, we decided to target enzymes involved in the propionate etabolism.
The pathways for propionate metabolism in Escherichia coli as well as Salmonella
typhimurium were just established and there were no structural information available for
most of the enzymes involved in these pathways. Since, propionate metabolic pathways were well described in the case of Salmonella typhimurium, we decided to use this as the model organism. We first started with the enzymes present in the propionate catabolic pathway “2-methylcitrate pathway”, which converts propionate into pyruvate and
succinate. 2-methylcitrate pathway resembles the well-studied glyoxylate and TCA cycle.
Most of the enzymes involved in 2-methylcitrate pathway were not characterized
biochemically as well as structurally. First, we cloned all the four enzymes PrpB, PrpC, PrpD and PrpE present in the prpBCDE operon along with PrpR, a transcription factor, with the help of Dr. P.S. Satheshkumar from Prof. H. S. Savithri’s laboratory. Since these five proteins were cloned with either N- or C-terminal hexa-histidine tag, they could be purified easily using one-step Ni-NTA affinity column chromatography. PrpB, PrpC and PrpD had good expression levels but with PrpE and PrpR, more than 50% of the expressed protein went into insoluble fraction, probably due to the presence of membrane spanning domains in these two enzymes. Around this time, crystallization report for the PrpD from Salmonella was published by Ivan Rayment’s group, so after that we focused only on the remaining four proteins leaving out PrpD. Our initial attempts to crystallize
these proteins became successful in case of PrpB, 2-methylisocitrate lyase. We collected
a complete diffraction data to a resolution of 2.5 Å which was later on extended to a
resolution of 2.1 Å using another crystal. Repeated crystallization trials with PrpC also gave small protein crystals but they were not easy to reproduce and size and diffraction quality always remained a problem. Using one good crystal obtained for PrpC, data to a resolution of 3.5 Å could be collected. Unfortunately, during data collection due to failure of the cryo-system, a complete dataset could not be collected. Further attempts to crystallize this protein made by Nandashree, one of my colleagues in the lab at that time, was also without much success. Attempts to purify and crystallize PrpE and PrpR were made by me as well as one of my colleagues, Anupama. In this case, besides crystallization, low expression and precipitation of the protein after purification were major problems.
Our attempt to phase the PrpB data using the closest search model (phosphoenolpyruvate mutase) by molecular replacement technique was unsuccessful,probably because of low sequence identity between them (24%). Further attempts were made to obtain heavy atom derivatives of PrpB crystal. We could obtain a mercury derivative using PCMBS. However, an electron density map based on this single derivative was not nterpretable. Around this time, the structure of 2-methylisocitrate lyase (PrpB) from E. coli was published by Grimm et. al. The structure of Salmonella PrpB could easily be determined using the E. coli PrpB enzyme as the starting model. We also solved the structure of PrpB in complex with pyruvate and Mg2+. Our attempts to crystallize PrpB with other ligands were not successful. Using the structures of PrpB and its complex with pyruvate and Mg2+, we carried out comparative studies with the well-studied structural and functional homologue, isocitrate lyase. These studies provided the
plausible rationale for different substrate specificities of these two enzymes. Due to
unavailability of PrpB substrate commercially and the extensive biochemical and mutational studies carried out by two different groups made us turn our attention to other enzymes in this metabolic pathway. Since our repeated attempts to obtain good
diffraction quality crystals of PrpC, PrpE and PrpR continued to be unsuccessful, we
decided to target other enzymes involved in propionate metabolism.
We looked into the literature for the metabolic pathways by which propionate is
synthesized in the Salmonella typhimurium and finally decided to target enzymes present
in the metabolic pathway which converts L-threonine to propionate. Formation of
propionate from L-threonine is the most direct route in many organisms. During February 2003, we initiated these studies with the last enzyme of this pathway, propionate kinase (TdcD), and within a couple of months we could obtain a well-diffracting crystal in complex with ADP and with a non-hydrolysable ATP analog, AMPPNP. TdcD structure was solved by molecular replacement using acetate kinase as a search model. Propionate kinase, like acetate kinase, contains a fold with the topology βββαβαβα, identical with that of glycerol kinase, hexokinase, heat shock cognate 70 (Hsc70) and actin, the superfamily of phosphotransferases. Examination of the active site pocket in propionate kinase revealed a plausible structural rationale for the greater specificity of the enzyme
towards propionate than acetate.
One of the datasets of TdcD obtained in the presence of ATP showed extra continuous density beyond the γ-phosphate. Careful examination of this extra electron
density finally allowed us to build diadenosine tetraphosphate (Ap4A) into the active site pocket, which fitted the density very well. Since the data was collected at a synchrotron source to a resolution of 1.98 Å, we could identify the ligand in the active site pocket solely on the basis of difference Fourier map. Later on, co-crystallization trials of TdcD with commercially available Ap4A confirmed its binding to the enzyme. These studies
suggested the presence of a novel Ap4A synthetic activity in TdcD, which is further being examined by biochemical experiments using mass-spectrometry as well as thin-layer chromatography experiments.
By the end of 2004, we shifted our focus to the first enzyme involved in the anaerobic degradation of L-threonine to propionate, a biodegradative threonine deaminase (TdcB). Sagar Chittori, who had joined the lab as an integrated Ph. D student, helped me in cloning this enzyme. My attempt to crystallize this protein became finally
successful and datasets in three different crystal forms were collected. Dataset for TdcB in complex with CMP was collected during a synchrotron trip to SPring8, Japan by my colleague P. Gayathri and Prof. Murthy. TdcB structure was solved by molecular replacement using the N-terminal domain of biosynthetic threonine deaminase as a search model. Structure of TdcB in the native form and in complex with CMP helped us to understand several unanswered questions related to ligand mediated oligomerization and enzyme activation observed in this enzyme.
The structural studies carried out on these three enzymes have provided structural
as well as functional insights into the catalytic process and revealed many unique features of these metabolic enzymes. All these have been possible mainly due to proper guidance and encouragement from Prof. Murthy and Prof. Savithri. Prof. Murthy’s teaching as well as discussions during the course of investigation has helped me in a great deal to learn and understand crystallography. Collaboration with Prof. Savithri kept me close to biochemistry and molecular biology, the background with which I entered the world of structural biology. The freedom to choose the project and carry forward some of my own ideas has given me enough confidence to enjoy doing research in future
Effect of Different Inoculum Level of Meloidogyne incognita on Chlorophyll Content of Pigeon Pea, Cajanus cajan (L.)
No full textA pot culture experiment was conducted during Kharif season in the year 2021- 2022 at Green polyhouse, Department of Nematology, College of Agriculture, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha in order to study effect of different inoculum level of M. incognita on chlorophyll content of pigeon pea. The experiment was laid out in Completely randomized design (CRD) with 5 treatments i.e T1 (500 J2/plant), T2(1000J2 / Plant), T3(1500J2/plant), T4(2000J2/plant), T5(Control)and 4 varieties were UPAS-120(R), IPA-15-1 (MR), IPA 14-7(S), CO-6(HS). To find out the effect of increase in inoculum level of nematode on chlorophyll content of pigeon pea leaves showed that highest reduction in chlorophyll in treatment T4 then T3, T2 and then T1 over control T5. The results have demonstrated that nematode infestation leads to highest decreased by 41.75% total chlorophyll content (a+b) in UPAS -120(R)) in the leaves and highest decrease found in case of high inoculum level inoculation of nematodes in the pigeon pea plant
Application of dynamic factor modelling to financial contagion
No full textContagion has been described as the spread of idiosyncratic shocks from one mar
ket to another in times of ?nancial turmoil. In this work, contagion has been
modelled using a global factor to capture the general market movements and
idiosyncratic shocks are used to capture co-movements and volatility spill-over
between markets. Many previous studies have used pre-speci?ed turmoil and
calm periods to understand when contagion occurs. We introduce time-varying
parameters which model the volatility spillover from one country to another. This
approach avoids the need to pre-specify particular types of periods using external
information. E?cient Bayesian inference can be made using the Kalman ?lter in
a forward ?ltering and backward sampling algorithm. The model is applied to
market indices for Greece and Spain to understand the e?ect of contagion dur
ing the European sovereign debt crisis 2007-2013 (Euro crisis) and examine the
volatility spillover between Greece and Spain. Similarly, the volatility spillover
from Hong Kong to Singapore during the Asian ?nancial crisis 1997-1998 has also
been studied.
After a review of the research work in the ?nancial contagion area and of the
de?nitions used, we have speci?ed a model based on the work by Dungey et al.
(2005) and include a world factor. Time varying parameters are introduced and
Bayesian inference and MCMC simulations are used to estimate the parameters.
This is followed by work using the Normal Mixture model based on the paper by
Kim et al. (1998) where we realised that the volatility parameters results depended
ii
on the value of the ‘mixture o?set’ parameter. We propose method to overcome
the problem of setting the parameter value.
In the ?nal chapter, a stochastic volatility model with with heavy tails for the
innovations in the volatility spillover is used and results from simulated cases and
the market data for the Asian ?nancial crisis and Euro crisis are summarised.
Brie?y, the Asian ?nancial crisis periods are identi?ed clearly and agree with
results in other published work. For the Euro crisis, the periods of volatility
spillover (or ?nancial contagion) are identi?ed too, but for smaller periods of
time.
We conclude with a summary and outline of further work
Transforming the old into a foundation for the new - lessons of the Moldova ARIA Project
No full textThis paper is a case study of what is recognized as one of the more successful projects in any country in the Europe and Central Asia region, not to mention in the poorest country of the region-Moldova. The ARIA project shows new ways to attack some of the most intractable problems of private sector development in Europe and Central Asia: how to facilitate reorganization and liquidation bankruptcies; how to promote small and medium enterprise spin-offs and new start-ups; and how to promote new learning at the enterprise level, both in the form of"Marshall Plan"programs with more advanced post-socialist countries, as well as continuous improvement programs (such as those adapted from Japanese programs). The prime mover for these programs is the quasi-public restructuring agency, ARIA, which was established as part of the Moldova Private Sector Development I loan. ARIA was structured to try to combine private sector entrepreneurship with a public function in the process of restructuring and bankruptcy. The study tries to account for the strategies and innovations that lead to results. And it tries to connect the ARIA strategy to past development literature by viewing the study through Albert Hirschman's work on social learning and change.Enterprise Development&Reform,Public Health Promotion,Banks&Banking Reform,Health Monitoring&Evaluation,Small Scale Enterprise,Health Monitoring&Evaluation,Banks&Banking Reform,Small Scale Enterprise,Microfinance,Private Participation in Infrastructure
"A Comparative Analysis of Cost Effectiveness on Productivity" - (With Special Reference to Saurashtra University and Gujarat University)
No full textNot availabl
Not Available
No full textNot AvailableNot AvailaRainfall is an important parameter for water resources application particularly in
rainfed agricultural system. Rainfall in Himalaya varies from palace to place due to
complex topography and it is hard to predict based on empirical formula. The objective
of the present study is to develop seasonal auto regressive integrative moving average
(SARIMA) model for Almora, Hawlbagh and Mukteshwar station located in Kumaon
region of Uttarakhand and to determine the accuracy of the developed model in the
same region. The present research utilized univariate time series rainfall model to
forecast rainfall in Kumon region. We have selected the best SARIMAmodel fitted to
our data which exhibited the least akaike information criterion (AIC) and bayesian
information criterion (BIC) values. Finally, we identified the best model separately for
each location after following three Box-Jenkings methodologies (model identification,
elimination of parameters and diagnostic checking). The selected model is evaluated for
residual normality test and observed data. The performance statistics of the developed
SARIMAmodels for monthly scale were found for Almora (RMSE = 26.55 mm, MAE
2 2
= 22.77 mm, R = 0.86), Hawalbagh (RMSE = 33.66 mm, MAE = 25.63 mm, R = 0.82)
2 and Mukteshwar (RMSE = 35.62 mm, MAE = 28.45 mm, R = 0.81). The performance
parameter of the developed models showed that the forecast result mimics well with
the observed rainfall data and also captures the extreme events well.bleNot Availabl
- …
