Use of response surface methodology for optimization of a shoot regeneration protocol in <Emphasis Type="Italic">Basilicum polystachyon</Emphasis>

Response surface methodology (RSM) is a collection of techniques useful for analyzing and optimizing problems where several explanatory covariates influence a response. Although this technique is extensively used in various mixture experiments, its application in standardization of micropropagation protocols is limited. The theoretical developments of RSM are usually concerned with continuous data; hence, linear model theory becomes relevant. In plant tissue culture, in which the response variables are mostly numerical data, the development of RSM in a generalized linear model (GLM) setup is of interest from both a theoretical as well as an application perspective. In the present paper, RSM, as applicable for count data, has been used for modeling, analyzing, and optimizing in vitro regeneration of multiple shoots of Basilicum polystachyon, an important medicinal plant. The specific issues addressed herein are the determination of the optimum concentration of plant growth regulators (i.e., the range of variation in dosages of each covariate) at which the regeneration potential of shoot tip explants is expected to increase, selection of the appropriate growth function (response function) of shoot tip, and determination of the optimum levels of the explanatory variables (i.e., the different combination of dosages of various control factors) for experimentation. According to the present analysis, the optimum level combinations of growth regulators for regeneration of multiple shoots from shoot tip explants of B. polystachyon is 8.19 μM benzyladenine and 2.36 μM naphthalene acetic acid, with a response of approximately 12 regenerated shoots.     

Characterization of two urease-producing and calcifying Bacillus spp. isolated from cement

Two bacterial strains designated as CT2 and CT5 were isolated from highly alkaline cement samples using the enrichment culture technique. On the basis of various physiological tests and 16S rRNA sequence analysis, the bacteria were identified as Bacillus species. The urease production was 575.87 U/ml and 670.71 U/ml for CT2 and CT5 respectively. Calcite constituted 27.6% and 31% of the total weight of sand samples plugged by CT2 and CT5, respectively. Scanning electron micrography (SEM) analysis revealed the direct involvement of these isolates in calcite precipitation. This is the first report of the isolation and identification of Bacillus species from cement. Based on the ability of these bacteria to tolerate extreme environment of cement, they have potential to be used in remediating the cracks and fissures in various building or concrete structures.     

Molecular characterization of the interferon-tau gene of the mithun (Bos frontalis)

The mithun (Bos frontalis) not only remains one of the most neglected ungulate species due to its remote range, but also has been identified as a vulnerable species due to its declining population. Augmenting its reproductive efficiency could be a strategy for reversing its population decline. Considering the importance of interferon-tau (IFNT) as a primary signal in establishing maternal recognition of pregnancy (MRP), the present study was undertaken to characterize the IFNT gene of the mithun. A 588 bp mithun IFNT (mitIFNT) gene was PCR amplified using genomic DNA as the template. Its nucleotide sequence comprised an entire open reading frame of 585 bp encoding a 195 amino acid pre-protein. In nucleotide sequence, the mitIFNT gene was more than 85% similar to the homologous genes of domestic and wild ruminant species characterized to date. However, phylogenetic analysis placed mitIFNT into a clade containing IFNT of the red deer, but not IFNTs of cow, sheep, or goats, or other wild ruminant species. Our characterization of mitIFNT represents the first complete sequence of any gene from the mithun.     

Effect of leaf leachates ofPolyalthia longifolia on the growth and nitrogen fixation ofAzolla pinnata

Summary Leachates of leaves of different age ofPolyalthia longifolia showed different activities on growth ofAzolla.The leachate of juvenile leaves showed the highest promotion as undiluted extract, in contract to the effects of leachates of mature and senescent leaves which had this effect when four times diluted.The growth and nitrogen concent ofAzolla were highest in October at all treatments, particularly at the treatment with four times diluted leachates from senescent leaves.The lowest growth rates ofAzolla due to different treatments were found in winter and in summer.     

Interaction of nogalamycin with chromatin

Number of available nogalamycin binding sites in Sarcoma-180 chromatin is less than that present in Sarcoma-180 DNA. Gradual removal of proteins from chromatin by salt leads to increase in available drug binding sites, without appreciable alteration in binding affinity. Histones restrict the accessibility of nogalamycin to chromosomal DNA, whereas high mobility group (HMG) proteins have no effect. Association of histone H1 with chromosomal DNA has a more marked inhibitory effect on nogalamycin binding than other types of histones. Chromosomal protein induced conformational change in DNA appears to be the main factor in determining the availability of strong binding sites.     

Molecular cloning and analysis of genes for sialic acid synthesis in Neisseria meningitidis group B and purification of the meningococcal CMP-NeuNAc synthetase enzyme.

The gene encoding for the CMP-NeuNAc synthetase enzyme of Neisseria meningitidis group B was cloned by complementation of a mutant of Escherichia coli defective for this enzyme. The gene (neuA) was isolated on a 4.1-kb fragment of meningococcal chromosomal DNA. Determination of the nucleotide sequence of this fragment revealed the presence of three genes, termed neuA, neuB, and neuC, organized in a single operon. The presence of a truncated ctrA gene at one end of the cloned DNA and a truncated gene encoding for the meningococcal sialyltransferase at the other confirmed that the cloned DNA corresponded to region A and part of region C of the meningococcal capsule gene cluster. The predicted amino acid sequence of the meningococcal NeuA protein was 57% homologous to that of NeuA, the CMP-NeuNAc synthetase encoded by E. coli K1. The predicted molecular mass of meningococcal NeuA protein was 24.8 kDa, which was 6 kDa larger than that formerly predicted (U. Edwards and M. Frosch, FEMS Microbiol. Lett. 96:161-166, 1992). Purification of the recombinant meningococcal NeuA protein together with determination of the N-terminal amino acid sequence confirmed that this 24.8-kDa protein was indeed the meningococcal CMP-NeuNAc synthetase. The predicted amino acid sequences of the two other encoded proteins were homologous to those of the NeuC and NeuB proteins of E. coli K1, two proteins involved in the synthesis of NeuNAc. These results indicate that common steps exist in the biosynthesis of NeuNAc in these two microorganisms.     

Cyclic GMP-phosphodiesterase inhibition does not alter cerebral oxygen consumption

The effect of zaprinast, a cyclic guanosine monophosphate inhibitor, on the level of cyclic GMP and cerebral O₂ consumption was determined. Anesthetized male Long-Evans rats were divided into a control group (n=15) and a zaprinast treated group (n=15). Vehicle was applied topically to the left cortex and 3·10⁻³ M zaprinast was applied to the right cortex. A saline treated control group was also studied. Regional cerebral blood flow was determined by [¹⁴C]-iodoantipyrine and regional O₂ extraction was determined by microspectrophotometry. The level of cyclic GMP was measured by radioimmunoassay. There were no hemodynamic or blood gas differences between groups. The level of cyclic GMP was not significantly different between the right and left cerebral cortex of the control group (17.0±4.3 and 17.7±4.6 pmol/g). In the zaprinast treated group, there was a significant (46%) increase in the level of cyclic GMP in the zaprinast treated cortex (20.5±8.1) in comparison to the vehicle treated cortex (14.0±5.7). Zaprinast did not significantly alter cerebral blood flow. There were no significant differences in regional O₂ extraction. The O₂ consumption of the zaprinast treated cortex (8.0±3.3 ml O₂·min⁻¹·100 g⁻¹) was not different from that of the vehicle treated cortex (7.0±2.9) or those of the control group. Thus, our data indicated that the increased level of cyclic GMP had no significant effect on cerebral oxygen consumption.