Experimental investigation on dispersing graphene-oxide in biodiesel/diesel/ higher alcohol blends on diesel engine using response surface methodology.

Lower alcohols have long been the figureheads of diesel/biodiesel additives in characterizing renewable fuels. Next-generation alcohol like n-octanol occupied the reified position due to their better fuel properties. In this paper, combustion, performance and, emission of different graphene-oxide nanoparticles (nanoGO) added jatropha biodiesel, n-octanol and petrodiesel blends are investigated in a 4-stroke DI diesel engine. This article also aims to optimize the engine inputs accountable for better performance and emission characteristics of a diesel engine running with nanoGO dispersed biodiesel/diesel/higher alcohol blends. Full Factorial Design-based Response Surface Methodology (RSM) is utilized to model the experiments using Design-Expert software to optimize engine responses. Validation of the developed model is carried out using sophisticated error and performance metrics, namely, TheilU2, Kling-Gupta Efficiency (K-G Eff), and Nash-Sutcliffe coefficient of efficiency (N-S Eff) along with the conventional statistical database. The model optimized engine inputs of 3.898% n-Octanol, and 49.772 ppm nanoGO at 99.2% load with a desirability index of 0.997 as the optimum engine parameters. The experimental validation revealed that the model optimized blend at full load witnessed a reduction of 15.6% CO, 21.78% HC.u, and 3.26% NOx emission compared to petrodiesel. However, a slight increase in brake specific energy consumption (2.95%) is also recorded because of the lower heating value of the blend.

Cloning and characterization of the unusual cyclin gene from an amphidiploid of Nicotiana glauca-Nicotiana langsdorffii hybrid.

Cyclins play an important role in the regulation of cell cycle progression in eukaryotic cells. As an aid to understanding the molecular nature of unregulated cell proliferation, a cDNA clone encoding a cyclin gene, GTcyc, was identified from genetic tumors. The clone contained 1095 bp including a 24 base poly(A) tail. GTcyc is an unusual cyclin gene, distantly related to mammalian cyclin D genes having 21-25% identity within the cyclin box. Northern blots showed that the genetic tumors express high levels of GTcyc relative to non-tumor hybrid tissues. Southern analysis suggests that GTcyc may be contained one or two families in genetic tumors.

Molecular analysis of the recA gene of Agrobacterium tumefaciens C58.

The complete nucleotide sequence of the Agrobacterium tumefaciens recA gene was determined. A comparison of the translated open reading frame of the gene with other known recA sequences revealed significant sequence conservation. However, unlike its Escherichia coli equivalent, A. tumefaciens recA lacks the upstream 'SOS box', suggesting a different mechanism of regulation for this gene.

Agrobacterium tumefaciens Is a Diazotrophic Bacterium.

This is the first report that Agrobacterium tumefaciens can fix nitrogen in a free-living condition as shown by its abilities to grow on nitrogen-free medium, reduce acetylene to ethylene, and incorporate N supplied as N(2). As with most other well-characterized diazotrophic bacteria, the presence of NH(4) in the medium and aerobic conditions repress nitrogen fixation by A. tumefaciens. The system requires molybdenum. No evidence for nodulation was found with pea, peanut, or soybean plants. Further understanding of the nitrogen-fixing ability of this bacterium, which has always been considered a pathogen, should cast new light on the evolution of a pathogenic versus symbiotic relationship.

Identification, cloning, and sequence analysis of the nitrogen regulation gene ntrC of Agrobacterium tumefaciens C58.

We describe the cloning of an ntrC gene of Agrobacterium tumefaciens C58 by interspecific complementation of an Escherichia coli ntrC mutant. Restriction mapping and Southern blot analysis of the complementing clone identified a 1.7-kb EcoRI-PvuII DNA fragment whose sequence was determined. Analysis of this sequence revealed coding regions corresponding to a complete ntrC gene and the C-terminal region of an ntrB gene. Amino acid sequence comparisons of A. tumefaciens NTRC protein with NTRC sequences from Rhizobium meliloti, Bradyrhizobium sp. (Parasponia), Klebsiella pneumoniae, E. coli, and Salmonella typhimurium show strong sequence conservation supporting DNA hybridization data, demonstrating strong evolutionary homology among ntrC genes of Rhizobiaceae. The C58 NTRC protein has been identified, by 35S-labeling, in a T7 RNA polymerase (pT7-7) expression vector system.

Klebsiella pneumoniae nif-lac fusions are expressed in Agrobacterium tumefaciens C58.

Plasmids containing hybrid genes, in which different Klebsiella pneumoniae nif (nitrogen-fixation) promoters were fused with the structural part of the Escherichia coli lac operon, were introduced into a double auxotrophic derivative of Agrobacterium tumefaciens C58. A study of their expression in the new host was made simple by the inherent inability of A. tumefaciens C58 to produce beta-galactosidase unless provided with the wild-type lac operon of E. coli. As shown by quantitative measurements of the enzyme, all K. pneumoniae promoters were expressed well in A. tumefaciens C58, even under conditions known to repress them. It also has been shown that the activity of K. pneumoniae nif A is essential for the expression of nifHDK even when introduced into A. tumefaciens. After entering the new host the plasmids, the nif genes and the fusion alleles contained in them, remained stable. Possible mechanisms responsible for the constitutive behaviour of nif promoters in A. tumefaciens are discussed.

Studies on Tn951 (lac+) expression in Agrobacterium.

None of the Agrobacterium tumefaciens and A. rubi strains tested produces detectable amounts of beta-galactosidase although they are capable of utilizing lactose as sole source of carbon. This opportunity was taken to investigate the expression of lac transposon Tn951 (Cornelis et al. 1978) in Agrobacterium with the ultimate goal of using this system to investigate alien gene expression. When the transposon was introduced with the help of a broad-host range plasmid, RP1, the transconjugants produced significant quantities of beta-galactosidase which was inducible by isopropyl-beta-D-thiogalactopyranoside. Tn951 was capable of restoring the Lac+ phenotype to an A. tumefaciens mutant not capable of using lactose. Cellobiose, a known inducer of aldohexopyranoside: cytochrome c oxidoreductase (which regulates the characteristic 3-ketolactose production in Agrobacterium; van Beeumen and De Ley (1968), had no effect on beta-galactosidase activity.

R68.45 mediated chromosomal gene transfer in Agrobacterium tumefaciens.

A large plasmid enables its host Agrobacterium tumefaciens to cause tumorous condition in a wide variety of dicotyledonous plants[see Ooms et al. Gene 14:33--50 (1981) )). The location and role of chromosomal genes in this phenomenon are not known. As the first stage in studying this aspect, a project was initiated to investigate the chromosomal genetics of the bacterium. R68.45, a P group plasmid, was chosen as a transmission agent. After a preliminary assessment it was decided to use C58 as a standard strain to carry out the mapping. The plasmid itself, as judged by the presence of antibiotic markers, appears to be stable in A. tumefaciens; its ability to promote chromosomal mobilisation, however, remains only in 60--80% transconjugants. Good Agrobacterium donors are capable of transferring chromosomal genes at a frequency varying between 10(-5) to 10(-6) per recipient. The recombinants are stable even under non-selective conditions. A linear linkage map consisting of 16 markers was built using coinheritance frequencies obtained from 21 four-point crosses.

Evidence for correlation between mutability of an unstable anthocyanin-governing locus and abundance of anthocyanin.

The pal-rec gene of Antirrhinum majus suppresses anthocyanin except in those cell lines where pal-rec has mutated to Pal, so that anthocyanin-coloured flecks appear on whitish petals. Antirrhinum majus families of very high and very low anthocyanin content (Dark and Pale) were obtained and crossed with two pal-rec pal-rec lines, one with consistently high and the other consistently low mutability. Mutable offspring from Dark parents tended to show higher mutability than those from Pale parents in crosses with either mutable line, providing evidence for an association between intense pigmentation and high mutability. Such an association is discussed in the context of relationship between precursor availability for conversion by a gene product and initiation of activity of that gene.

Genetic instability of anthocyanin production in Impatiens balsamina.

It is established that in a naturally occurring variegated Impatiens balsamina the phenotype is determined by a mutable allele p (m), of an anthocyanin-governing gene P (r). The special allele produces an acyanic phenotype like the stable recessive p but undergoes frequent changes to P (r) in somatic and germinal cells (causing a variegated phenotype in the former) when a controlling element M is also present in the genome. It is suggested that p (m) is a repressed p (r) and M acts either by removing or inactivating whatever causes that repression. Such changes proceed in a unique fashion: either p (m) changes to p (r) or to an intermediate labile condition P' which then changes to p (r), resulting either in dark or pale, or dark super-imposed on pale, sectors; a reverse situation was not observed. Colourless plants which occasionally appear in unstable lines seem to be due to loss of M although changes ofp (m) itself cannot be ruled out at present.

Provocation of mutability in the level of mutation expressed at the pal-rec gene in Antirrhinum majus.

The pallida gene of Antirrhinum majus governs anthocyanin production. The nature of the mutability displayed by its unstable allele pal-rec was dramatically altered following crosses between two pal-rec pal-rec lines with certain separately maintained lines. In both cases a minority of progeny in F1 or F2 revealed unprecedented infrequent mutability termed 'Low mutability'. These Low plants and their sibs showed many areas of contrasting mutability superimposed on their initial mutability level. This frequent 'shifting' and Low mutability persisted through several generations of offspring obtained by both selfing and crossing to a non-mutable tester line. Evidence is presented to suggest a hypothesis that the two features of altered mutability are two aspects of the same phenomenon caused by joint action of two independent factors J and k, one contributed by each parental line at the outcross.A separate gene, eosinea, governs anthocyanin type, eos eos plants having pelargonin in place of wild-type magenta cyanin. In addition to the previously known simple depression of pal-rec to Pal mutation frequency in eos eos plants, eos also influences the action of J and k when heterozygous (i.e. Eos eos), thus contributing a basal and a third tier of control influencing mutability of pal-rec.Three levels of control are thus identified, the middle tier being governed by the partnership of J and k producing not a simple change but a complex mutability of mutability.

Paramutation and mutation of R (ch) in maize.

1. In maize, R (ch) conditions anthocyanin pigmentation in aleurone, anthers, silks and reacts with another factor Pl to produce cherrycoloured pericarp, thus representing the broadest pigmentation pattern among all the alleles at the R locus. The paramutational and mutational behaviour of R (ch) are reported here. 2. R (ch) is paramutable with respect to its action in the aleurone, but its pigmenting ability in the pericarp is not sensitive to the paramutagenic action of R (st) . 3. The mutation experiments revealed that R (ch) is a compound locus containing at least four different components: (P) affecting anthocyanin in anthers, (Si) conditioning pink silks, (Ch) reacting with Pl to produce cherry pericarp, and (S) affecting aleurone pigmentation. 4. Different interactions of R (ch) with independent genes support the conclusions drawn from mutation experiments. 5. It is suggested that different components of the R (ch) locus are unequally sensitive to the action of R (st) .