Inheritance of morphological traits of periwinkle mutants with modified contents and yields of leaf and root alkaloids

Periwinkle Catharanthus roseus is a medicinally important plant producing anticancer and antihypertension alkaloids. Two mutants, one dwarf and one semidwarf and both, with a high alkaloid content in the roots and one mutant with a wavy leaf margin and a high alkaloid content in its leaves were obtained after induced chemical mutagenesis with ethyl methane sulphonate and N-nitroso-N-ethylurea in the variety ‘Nirmal’, which is resistant to dieback disease. These mutants were evaluated in the M₃ and M₄ generations. The dwarf and semidwarf mutants differed from the parental variety for many morphological characters, while the mutant with the wavy leaf margin differed mainly in leaf size and leaf thickness. Although both dwarf and semidwarf mutants showed a significantly higher alkaloid content in their roots in both generations, only the semidwarf mutant gave a significantly higher (23%) root alkaloid yield than the parental variety. The mutant with the wavy leaf margin showed a significantly higher alkaloid content in the leaves in both the M₃ and M₄ generations and also had a significantly higher (21%) leaf alkaloid yield than the parental variety. All three mutants were found to be controlled by monogenic recessive genes; the genes for ‘dwarfness’ and ‘semidwarfness’ were allelic to each other, with the allele for semidwarfness being dominant over the allele for dwarfness. The gene for the wavy leaf margin was inherited independently of the genes for dwarfness and semidwarfness.     

Escherichia coli 'O' group serological responses and clinical correlations in epidemic HUS patients

This first comprehensive serological analysis of an haemolytic uraemic syndrome (HUS) outbreak in which a wide range of 'O' group Escherichia coli antibody responses in patients and controls provided a unique insight into the epidemiology of such epidemics. Possible answers to clinical aspects related to severity of disease and complications were revealed. A microagglutination assay was used to examine E. coli 'O' group serological responses in 49 serum samples of 21 children hospitalised with HUS and 14 single samples from contemporaneous age-matched controls. A total of 51 O serogroup strains were used, including those reported to be associated with cases of HUS, with six isolates from patients associated with the Adelaide outbreak, environmental verocytotoxi-genic/shiga-toxin producing E. coli (VTEC/STEC) strains and common human commensal strains. Amongst the 21 patients, there were 226 instances of seroreactivity (titre > or = 100) against 34 E. coli serogroups while six instances of seroreactivity against four serogroups occurred in controls. There were 128 instances in patients and one instance in controls in which titres > or = 400 were observed. All 21 patients were seroreactive (titre > or = 100 and <400) to one or more of the 17 HUS-associated serogroups included in the study. Titres ranged from 100 to 6,400, some of the highest in three patients were against O157, whose faeces yielded only EHEC O111, and only one developed O111 antibody. Mixed infection was demonstrated serologically by microagglutination (confirmed by western blot) and was consistent with the multiple serogroups of VTEC found in the mettwurst incriminated as the source, and suggests further strains (not found in the source or in patients' faeces) were probably involved. In HUS-associated EHEC infection, multiple strain infection may be the rule rather than the exception. Analysis of 34 of the 51 serogroup antibody responses in the HUS patients revealed clues to possible relationships with clinical severity and complications. Patients with severe renal failure tended to develop antibodies to a larger number of serogroups than those with moderate or mild impairment. The same was true for central nervous system complications. Other associations were observed. While VTEC O157 remains an important causal serogroup in HUS, non-O157 serogroups also appear to play a significant role and therefore the latter should always be sought in all future HUS cases as new insights into pathogenicity may be discovered. This study indicates that co-infection with different VTEC serogroups may affect clinical outcome.     

On-farm evaluation of two fast growing trees for biomass production for industrial use in Andhra Pradesh,Southern India

On-farm experiments were conducted in Khammam district of Andhra Pradesh from 2001 to 2006 to evaluate the biomass productivity, intercrop yields and profitability of Eucalyptus tereticornis clonal and Leucaena leucocephala variety K-636 based systems. Trees were planted at a spacing of 3 × 2 m and evaluated at three locations. Height growth was significantly higher in leucaena during the 4 year where as difference in diameter growth was not significant. Biomass partitioning to the bole was high in case of leucaena, ranged from 83% in 2.5–5 cm diameter at breast height (DBH) trees to 89% in 12.5–15 cm DBH trees and in eucalyptus clones the corresponding values were 71% in 2.5–5 cm DBH trees and 83% in 12.5–15 cm DBH trees. Marketable biomass productivity was higher with leucaena (95 Mg ha⁻¹) in comparison to eucalyptus (87 Mg ha⁻¹). Competition effects of trees on intercrops were observed from the 2 year (2002 post-rainy season). Intercrop yields were 45% of the sole crop in eucalyptus system and 36% in leucaena system during the 2 year. Sole eucalyptus and leucaena plantations and intercropping systems recorded higher gross and net returns over arable cropping. Therefore, it can be concluded that leucaena variety K636 and eucalyptus clonal based agroforestry systems are profitable alternatives to arable cropping under rainfed conditions.     

Glycolipid antigen processing for presentation by CD1d molecules

The requirement for processing glycolipid antigens in T cell recognition was examined with mouse CD1d-mediated responses to glycosphingolipids (GSLs). Although some disaccharide GSL antigens can be recognized without processing, the responses to three other antigens, including the disaccharide GSL Gal(alpha1-->2)GalCer (Gal, galactose; GalCer, galactosylceramide), required removal of the terminal sugars to permit interaction with the T cell receptor. A lysosomal enzyme, alpha-galactosidase A, was responsible for the processing of Gal(alpha1-->2)GalCer to generate the antigenic monosaccharide epitope. These data demonstrate a carbohydrate antigen processing system analogous to that used for peptides and an ability of T cells to recognize processed fragments of complex glycolipids.     

Label-free, single-molecule detection with optical microcavities

Current single-molecule detection techniques require labeling the target molecule. We report a highly specific and sensitive optical sensor based on an ultrahigh quality (Q) factor (Q > 10(8)) whispering-gallery microcavity. The silica surface is functionalized to bind the target molecule; binding is detected by a resonant wavelength shift. Single-molecule detection is confirmed by observation of single-molecule binding events that shift the resonant frequency, as well as by the statistics for these shifts over many binding events. These shifts result from a thermo-optic mechanism. Additionally, label-free, single-molecule detection of interleukin-2 was demonstrated in serum. These experiments demonstrate a dynamic range of 10(12) in concentration, establishing the microcavity as a sensitive and versatile detector.     

Insulin Secretagogue,Alpha-glucosidase and Antioxidant Activity of Some Selected Spices in Streptozotocin-induced Diabetic Rats

Spices are extensively used to enhance the taste and flavor of foods and are known to possess several medicinal properties. Myristica fragrans, Parmelia perlata, Illicium verum, Trachyspermum copticum and Myristica malabarica, the commonly used spices in India were assessed for antidiabetic activity in streptozotocin induced diabetic rats. In the in vitro insulin secretion studies on isolated islets of Langerhans, M. fragrans, T. copticum and M. malabarica showed dose dependent insulin secretion. At 1 mg/ml, P. perlata showed significant in vitro alpha-glucosidase inhibitory activity with IC₅₀ value of 0.14 mg/ml followed by M. malabarica (0.64 mg/ml), I. verum (0.67 mg/ml), M. fragrans (0.85 mg/ml) and T. copticum (0.92 mg/ml). The DPPH free radical scavenging activity of the extracts at a concentration of 1 mg/ml was as M. malabarica (90.45%), M. fragrans (89.89%), I. verum (87.22%), P. perlata (76.70%) and T. copticum (38.14%). P. perlata showed the highest phenolic content (i.e., 118.5 mg gallic acid equivalents/g) followed by M. malabarica (84.13 mg gallic acid equivalents/g). M. malabarica showed the highest flavonoid content (i.e., 38.35 mg quercetin equivalents/g). Regular use of these spices may prevent postprandial rise in glucose levels through inhibition of intestinal alpha-glucosidase and may maintain blood glucose level through insulin secretagogue action.