172 research outputs found
Author and Owner Intersection in Sound Recordings in The Copyright Act of India
No full text245-250The present work focuses on the intersection of author and owner concerning sound recordings. The interpretation of copyright law on the author and owner intersection by the Court's are rather varied. It may be because the restricted issues at its hand lead the courts. More particularly, interpretation of provisos (b) and (c) of Section 17 of The Copyright Act, 1957 leads to differing interpretations by the Courts. The present analysis is made by studying three recent judgments to understand the author and owner conflicts of sound recordings
Reduce the complexity of the E-learning authoring process
No full textFor every problem, there is one solution which is simple, neat, and wrong. The production of E-Learning contents is today the largest cost factor in the E-Learning and also the major issue of insecurity. This is an obstacle with the further propagation of the E-Learning. At present there are hardly visible numbers of tools to the production of E-Leaning contents. Besides the partial very high prices for this software they have the deficiency that they are usable only after a training course phase by the E-Learning author due to their complexity and its extent. The new challenge for designers and the researchers is to develop software tools for effective E-Learning. This Master thesis proposes an E-learning authoring tool which automatically uploads the file (OpenOffice document) which is selected by the enduser to the LMS/server. It also narrates how the content and the metadata are transformed as a SCORM package as well as its simplicity comparing to the other tools
Distinct RNA profiles in subpopulations of extracellular vesicles: apoptotic bodies, microvesicles and exosomes
No full textIntroduction: In recent years, there has been an exponential increase in the number of studies aiming to understand the biology of exosomes, as well as other extracellular vesicles. However, classification of membrane vesicles and the appropriate protocols for their isolation are still under intense discussion and investigation. When isolating vesicles, it is crucial to use systems that are able to separate them, to avoid cross-contamination. Method: EVs released from three different kinds of cell lines: HMC-1, TF-1 and BV-2 were isolated using two centrifugation-based protocols. In protocol 1, apoptotic bodies were collected at 2,000×g, followed by filtering the supernatant through 0.8 µm pores and pelleting of microvesicles at 12,200×g. In protocol 2, apoptotic bodies and microvesicles were collected together at 16,500×g, followed by filtering of the supernatant through 0.2 µm pores and pelleting of exosomes at 120,000×g. Extracellular vesicles were analyzed by transmission electron microscopy, flow cytometry and the RNA profiles were investigated using a Bioanalyzer®. Results: RNA profiles showed that ribosomal RNA was primary detectable in apoptotic bodies and smaller RNAs without prominent ribosomal RNA peaks in exosomes. In contrast, microvesicles contained little or no RNA except for microvesicles collected from TF-1 cell cultures. The different vesicle pellets showed highly different distribution of size, shape and electron density with typical apoptotic body, microvesicle and exosome characteristics when analyzed by transmission electron microscopy. Flow cytometry revealed the presence of CD63 and CD81 in all vesicles investigated, as well as CD9 except in the TF-1-derived vesicles, as these cells do not express CD9. Conclusions: Our results demonstrate that centrifugation-based protocols are simple and fast systems to distinguish subpopulations of extracellular vesicles. Different vesicles show different RNA profiles and morphological characteristics, but they are indistinguishable using CD63-coated beads for flow cytometry analysis
The degradation of silicone coatings in high temperature atmospheres
No full textTo evaluate the degradation of silicone based coatings that protect the mild steel surfaces from corrosion in high temperature atmospheres, the coatings were exposed to muffle furnace for heating ‐ cooling cycle (as per ASTM specification D 2485) up to 700°C. The ability of the paint film to withstand the temperature is related to its resistance as well as microcracks. These factors are very useful in precisely quantifying the degree of deterioration of the protective film. In the present work, two types of silicone based paints (silicone‐titanate, rhodorsil silicone) were prepared and the surface degradation of these coatings were studied by EIS technique and SEM with EDAX analysis. The chemical resistance properties were also analyzed.</jats:p
Tolerance and biosorption of cadmium (II) ions by highly cadmium resistant bacteria isolated from industrially polluted estuarine environment
No full text580-588In
the present study, totally 20 bacterial strains were isolated from two sites of
study area and also screened their tolerance against cadmium (II) ions. Among
the strains, 6 strains were screened as cadmium resistant and remaining 14 strains
as cadmium sensitive. Colony morphology, staining and biochemical test showed that
highly cadmium resistant bacteria (HCRB) NT-1, NT-5, NT-10, TT-5, TT-8 and
TT-10 belongs to Bacillus sp. Enterobacter sp., Aeromonas sp.,
Bacillus sp., Aeromonas sp., and Pseudomonas sp.
respectively. Biosorption potential of HCRB (NT-1, NT-5, NT-10 and TT-10) was
assessed in the 100 mg/l Cd (II) ions containing marine broth. Strain TT-10
showed maximum percentage (99 %) of cadmium removal in CdCl2. 5H2O
treated broth when compared to other resistant isolates. This study infers that
cadmium
resistant bacteria such as Pseudomonas sp. (TT-10) are valuable
candidates for bioremediation of cadmium contaminated ecosystem
Structural and Functional Studies on Salmonella typhimurium Propionate Kinase and Photorhabdus luminescens Oxalate Decarboxylase
No full textAcetate and propionate are low molecular mass carbon compounds found abundantly in the soil. Although these compounds have been extensively used as food preservatives because of their ability to inhibit microbial growth, surprisingly, bacteria such as Escherichia coli and Salmonella typhimurium are able to grow on propionate as their sole carbon and energy source. Only in the presence of glucose, acetate and other short chain fatty acids inhibit microbial growth.
Propionate is produced during the β-oxidation of odd-numbered carbon-chain fatty acids, fermentation of carbohydrates, oxidative degradation of branched-chain amino acids such as valine and isoleucine. They are also produced during the catabolism of threonine, methionine, thymine and cholesterol. In Escherichia coli and Salmonella typhimurium, enzymes involved in the degradation of L-serine and L-threonine to acetate and propionate, respectively, are encoded by the anaerobically regulated tdc operon. L-threonine is anaerobically degraded to propionate in four consecutive reaction steps catalyzed by biodegradative threonine deaminase (TdcB), 2-ketobutyrate formate lyase (TdcE), phosphotransacetylase (Pta) and propionate kinase (TdcD). Detailed studies on the structure and function of two of these enzymes have earlier been carried out in our laboratory. However, these studies did not reveal the precise substrate binding site in Salmonella typhimurium TdcD (StTdcD). It was also not possible to provide a satisfactory explanation of the structural basis of substrate specificity. The present studies were therefore aimed at locating the substrate binding site, elucidating the structural basis of substrate specificity and mechanism of catalysis of StTdcD.
Oxalic acid is toxic to almost all organisms and its excessive occurrence leads to a variety of pathological conditions. In humans and other vertebrates, secretion of oxalic acid leads to formation of low soluble calcium oxalate, which precipitates as kidney stones. Formation of kidney stones is aggravated by lack of enzymes that catabolize oxalate. Oxalate oxidase, oxalate decarboxylase and oxalyl-CoA decarboxylase constitute three distinct categories of oxalate degrading enzymes. Photorhabdus luminescens is a Gram-negative, symbiotic bacterium associated with the entomopathogenic nematodes of the family Heterorhabditidae. Novel insecticidal genes from these symbiotic bacteria are now being examined for their potential in generating pest resistant transgenic plants. As part of this project, the three-dimensional X-ray crystal structure of an oxalate oxidase (OXDC) enzyme from Photorhabdus luminescens (PlOXDC) was determined.
The introductory chapter (Chapter I) of the thesis presents the earlier investigations carried out in the laboratory on the structure and function of StTdcD. It also provides a summary of the earlier literature pertaining to propionate metabolism in S. typhimurium. The crystal structure of StTdcD in the apo form as well as in complex with ADP and the non-hydrolysable nucleotide analog AMPPNP were determined by earlier Dr. Simanshu ( Simanshu et al., 2005 , 2008 ). Subsequently, Dr Chittori determined the structures of the enzyme in complex with various other nucleotides ( Chittori et al., 2013 ). These studies along with enzyme assays performed by Chittori revealed that StTdcD possesses broad specificity and it could be activated by various nucleotides and metal ions and catalyzes phosphorylation of both propionate and acetate ( Chittori et al., 2013 ). In spite of these extensive studies, the precise mode of binding of the substrate propionate to StTdcD could not be elucidated. The chapter also presents a summary of the literature on oxalate, its toxic effects and enzymes that degrade oxalate. The importance of structural and functional studies on oxalate degrading enzymes and other enzymes encoded by Photorhabdus luminescens is also briefly discussed.
All the experimental protocols and computational methods applicable for most of the investigations reported in Chapters 4, 5 and 6 are presented in Chapter II. The experimental procedures described include cloning, overexpression, purification, enzymatic assays, crystallization and X-ray diffraction data collection. Computational methods covered include summary of crystallographic theory and details of various programs used during data processing, structure solution, refinement, model building, validation and analysis. The databases that were used in the course of these investigations are also cited.
The experience gained during attempts to determine the structure of StTdcD by single wavelength anomalous dispersion (SAD) method is described in Chapter III. The impetus for this work was the urge to examine the power of SAD technique making use of a newly acquired rotating anode X-ray generator equipped with a chromium anode. As expected, the structure determined by SAD was very close to the earlier determined structure of StTdcD. The structure contained a citrate, which was part of the crystallization cocktail at the active site. This is in contrast with acetate kinase, where it was found that citrate binds at the dimeric interface. The present studies demonstrated that the identification of a plausible regulatory site at the interface of dimeric structure in acetokinases based on the structure of acetate kinase (Chittori et al., 2013) is not valid for propionate kinase.
Extensive efforts carried out to obtain structures of StTdcD and its mutants StTdcD A88V and StTdcD G207A complexed with either the substrate or substrate analogues provided several crystal structures. In most of these structures, the ligand was bound at a position distinct from the substrate binding site. These structures and their analysis are described Chapter IV. Asn206 was transformed from a disallowed region to an allowed region of the Ramachandran map in these structures whenever an anion was bound at the position corresponding to the γ- phosphate of the nucleotide substrate. This structural transformation might enhance the affinity of the enzyme for the substrate. In the structure of StTdcD A88V in complex with AMPPNP, AMPPNP was found to be cleaved to AMP and PNP either due to catalytic activity of the enzyme or due to radiation damage. The released PNP probably reacted with propionate forming propionyl-pyrophosphate. These structures also demonstrate that the nucleotide site readily accommodates the substrate or substrate analogues in the absence of a bound nucleotide.
StTdcD catalyzes the Mg2+ ion dependent inter-conversion of propionate and ATP to propionyl phosphate and ADP. Two distinct catalytic mechanisms have been proposed for the phosphoryl transfer reaction catalyzed by acetokinase family enzymes: 1) direct-in-line transfer mechanism and 2) triple displacement mechanism (Anthony and Spector, 1972; Matte et al., 1998). In both, the configuration of the transferred phosphate undergoes an inversion, which has been experimentally demonstrated. Structural studies carried out with the view of elucidating the catalytic mechanism of StTdcD is described in Chapter V. Fortunately, it was possible to obtain the crystal structures of StTdcD and its mutants with propionate and AMPPNP bound at the active site. The structure supported an associative SN2 type direct in-line transfer mechanism of catalysis. The studies also revealed that Arg236 and His175 are catalytically important residues. As suggested earlier, Ala88 has a major role in specificity determination. However, Ala88 is not the sole determinant of specificity. Active site volume determining residues, Arg86, His118, Asp143 and the segment Pro116-Leu117-His118 are also important for substrate specificity. The catalytic mechanism proposed in this chapter may also be applicable to other acetokinase family members.
The final Chapter VI describes three different crystal structures of PlOXDC. As expected from sequence similarity with B. subtilis and T. maritima OXDCs, PlOXDC polypeptide was found to possess a bicupin structure. However, the functional unit was a trimer in contrast to BsOXDC which functions as a hexamer. The difference is shown to be due to the disorder in the amino terminal segment of PlOXDC. The polypeptide was truncated during purification by a non-specific cleavage at residue Lys26 either by thrombin used for cleaving the covalently attached GST tag or by some other protease. However, in the crystal structure, the amino terminal 90 residues were disordered. The observed trimeric form of PlOXDC may represent its inherent nature or a result of the missing N-terminal residues. There is some controversy in the literature on whether both or only one cupin domain of the protomer is catalytically active. The structures presented in this chapter provided significant information on the mode of ligand binding to PlOXDC. In one of the structures, EDO was bound to both the cupin domains and was involved in similar interactions with protein atoms. This may imply that the substrate binds at both the sites and both cupin domains may have catalytic function.
The thesis ends with a short note on future perspectives. It is clear that substantial work has been carried out on acetokinases. These studies have provided significant understanding of their structure and function. In the future, appropriate site-specific mutations of the substrate specificity determining residues may be made and their effect on enzyme specificity could be studied. Similarly, mutagenesis experiments could be performed to inter-convert acetate, propionate and butyrate kinases. These studies will provide deeper insights on intricacies of enzyme function. In contrast to the work on short chain fatty acid kinases, work on OXDC should be considered preliminary and further biochemical and structural studies are needed to illustrate the catalytic mechanism and examine if the protein is a suitable candidate for generating transgenic crops resistant to insect pests.
The following manuscripts have been published or will be communicated for publication based on the results presented in the thesis
Biochemical Alterations in the Haemolymph of Silkworm [Bombyx mori (L).(Lepidoptera: Bombycidae)] Fed with Mulberry Leaves Enriched with Indian Bean (Dolichos lablab)
No full textA study was carried out to evaluate the effect of Indian bean (Dolichos lablab) supplementation on silkworm. Finely powdered Dolichos lablab was dissolved in distilled water and diluted to 2.5 %, 5 %, 7.5 % and 10 % concentrations. Fresh mulberry leaves (Morus alba L.) were sprayed by each concentration and were fed to silkworms, from 3rd to 5th instar, five feedings/day. Group 1 larvae received mulberry leaves sprayed with distilled water and served as control, group 2 larvae received 2.5% Dolichos lablab sprayed mulberry leaves, group 3 larvae received 5 % Dolichos lablab sprayed mulberry leaves, group 4 larvae received 7.5 % Dolichos lablab sprayed mulberry leaves and group 5 larvae received 10 % Dolichos lablab sprayed mulberry leaves. Silkworm larvae fed on Morus alba. L. (mulberry) leaves enriched with 7.5 % concentrations of Dolichos lablab, significantly gained more Cocoon weight, Shell weight and Shell/cocoon ratio as compared to those fed on normal MR2 mulberry leaves. Hence, 7.5% dose was fixed as an effective dose. Further, same study was conducted to find out the biochemical changes in the haemolymph occurred in the first day of Vth instar larvae. There was a significant increase in the haemolymph glucose, cholesterol, urea, total protein, aspartate transaminase, alanine transaminase and alkaline phosphatase. But haemolymph uric acid was significantly decreased. The results suggest that coadministration of  Dolichos lablab with mulberry leaves at a concentration of 7.5% has enhanced the biochemical reaction involved in the silk production in the silkworm.  ÂÂ
A study on the impact of Plant Growth Promoting Fungus (PGPF) and Plant Growth Promoting Rhizobacteria (PGPR) as biofertilizers for Abelmoschus esculentus (L.) Moench.
No full textIn this study, the effectiveness of plant growth promoting fungus (PGPF) and plant growth promoting rhizobacteria (PGPR) on Bhendi (Abelmoschus esculentus (L.) Moench) was estimated. Germination study was conducted with Bhendi seeds treated in different PGPR and PGPF. The growth indices like vigour index, seedling growth, shoot length, root length, total leaf area, fresh weight and dry weight and yield parameters were taken into consideration for this experiment. All these morphological growth parameters gradually increased with PGPF and PGPR when compared to control. On the basis of germination study data, the best growth of bhendi seedling was recorded in PGPF followed by PGPR when compare with control
Studies on the Growth Rate of Silkworm Bombyx mori (L.) (Lepidoptera: Bombycidae) Fed with Control and Silver Nanoparticles (AgNps) Treated MR2 Mulberry Leaves
No full textTo evaluate the growth rate of larval and pupal parameters of silkworm Bombyx mori fed with Silver Nanoparticles (AgNps) treated MR2 mulberry leaves, the following works have been considered. The AgNp was synthesized by chemical reduction method, it was diluted by different concentrations such as 25%, 50%, 75 % and 100 % (without dilution). Fresh mulberry leaves (Morus alba L.) were sprayed by each concen-tration and were fed to silkworms, from 3rd, 4th and 5th instar, five feedings/day. Group T1 larvae received MR2 mulberry leaves sprayed with distilled water and served as control, group T2, T3, T4 and T5 larvae received 25%, 50%, 75 % and 100 % AgNps sprayed mulberry leaves, respectively. Silkworm larvae fed on M. alba (MR2) leaves sprayed with 25 % concentration of AgNps (group T2) was significantly increased the larvae and cocoon length, width and weight as com-pared to those fed on control (group T1) MR2 mul-berry leaves and other groups (T3, T4 and T5). Hence, 25 % AgNps dose was fixed as an effective dose. It has been observed from the present study that 25 % AgNps treated (group T2) leaves fed by silkworms have enhanced the larval and pupal growth and quantity of silk production than control
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