RasG protein accumulation occurs just prior to amoebae emergence during spore germination in Dictyostelium discoideum

Abstract RasG protein levels in dormant and germinating spores of Dictyostelium discoideum strains JC1 and SG1 were estimated by Western blotting. Ras Glevels were very low in dormant spores and remained low during the lag period, regardless of whether spores were heat activated or treated with autoactivator during the early stages of spore germination. RasG levels increased late during spore swelling just prior to the emergence stage of germination. These data are consistent with a requirement for RasG during vegetative growth.     

Inhibition by 2,4-D of somatic embryogenesis in carrot as explored by its reversal by difluoromethylornithine

The development of somatic embryos is, in many plants, inhibited by 2,4-dichlorophenoxyacetic acid (2,4-D) and other auxins. The finding that difluoromethylornithine (DFMO) can counteract this inhibition has been used to test some of the hypotheses for the mechanism of inhibition.
Inhibition of somatic embryogenesis in carrot ( Daucus carota L.) by exogenous ethylene (from ethephon), antioxidants (ascorbic acid and glutathione), ethanol/acetaldehyde and abscisic acid was not counteracted by DFMO, indicating that the inhibitory effect of 2,4-D is not manifest through the formation of these compounds. Embryogenesis was abolished by micromolar concentrations of the polar auxin transport inhibitors 2, 3, 5-triiodobenzoic acid (TIBA), N-1-naphthylphthalamic acid (NPA) and 9-hydroxyfluorene-9-carboxylic acid (HFCA). This inhibition was counteracted to a considerable extent by DFMO. Inhibition by relatively high concentrations of the antiauxin 2-( p -chlorophenoxy)-isobutyric acid (CPIB), which does not affect polar auxin transport, was in contrast not counteracted by DFMO. These findings indicate that exogenous auxins may inhibit embryogenesis by interfering with the ability of postglobular embryos to set up internal auxin gradients necessary for polarized growth.     

Some new results on Cox–Czanner divergence and their applications in survival studies

In the present communication, we propose a quantile-based measure for the divergence between two survival functions. This can also be used in a dynamic way where the divergence between survival functions varies with time. Several new properties of the proposed measure are investigated with suitable examples. The behavior of the measure for various reliability models is also investigated. A real data analysis is employed to compare the relative efficacy of two treatment groups using the proposed divergence measure.     

Purification, properties, and immunological characterization of GalT-3 (UDP-galactose: GM2 ganglioside, β1-3 galactosyltransferase) from embryonic chicken brain

A 1-3 galactosyltransferase (GalT-3; UDP-Gal; GM2 1-3galactosyltransferase) was purified over 5100-fold from 19-day-old embryonic chicken brain homogenate employing detergent solubilization, -lactalbumin Sepharose, Q-Sepharose, UDP-hexanolamine Sepharose, and GalNAc1-4Gal-Synsorb column chromatography. The purified enzyme was resolved into two bands on reducing gels with apparent molecular weights of 62 kDa and 65 kDa, respectively. GalT-3 activity was also localized in the same regions by activity gel analysis and sucrose-density gradient centrifugation of a detergent-solubilized extract of 19-day-old embryonic chicken brain. Purified GalT-3 exhibited apparentK _mS of 33 µm, 22 µm and 14.4mM with respect to the substrates GM2, UDP-galactose, and MnCl₂, respectively. Substrate specificity studies with the purified enzyme and a variety of glycosphingolipids, glycoproteins, and synthetic substrates revealed that the enzyme was highly specific only for the glycosphingolipid acceptors, GM2 and GgOse3Cer (asialo-GM2). Ovine-asialo-agalacto submaxillary mucin inhibited the transfer of galactose to GM2 but did not act as an acceptor in the range of concentrations tested. Polyclonal antibodies raised against purified GalT-3 inhibited GalT-3 activityin vitro and Western-immunoblot analysis of purified GalT-3 showed immunopositive bands at 62 and 65 kDa.Abbreviations CNS central nervous system - GM1 monosialotetraosylganglioside, Gal1-3GalNAc1-4(NeuAc2-3)Gal1-4Glc1-1Cer - GM2 monosialotriaosylganglioside, GalNAc1-4(NeuAc2-3)Gal1-4Glc1-1Cer - DSS detergent solubilized supernatant - ECB embryonic chicken brain - TBS Tris-buffered saline     

Genetics of high level penicillin resistance in clinical isolates of Streptococcus pneumoniae

Abstract Mosaic penicillin-binding proteins (PBP) 1A, 2X and 2B genes were cloned from four clinical isolates of Streptococcus pneumoniae with levels of susceptibility to penicillin ranging from 1.5 to 16 μg benzylpenicillin ml⁻¹. In each instance it was possible to transform either the penicillin-sensitive laboratory strain R6 or a sensitive clinical isolate 110K/70 to the full level of penicillin resistance with these three penicillin-binding proteins alone. Until now it has not been possible to clearly determine whether alterations to PBP1A, 2X and 2B alone were sufficient to attain high level penicillin resistance.     

Glycerolipid biosynthesis in rat adipose tissue 12. Properties of Mg2+-dependent and -independent phosphatidate phosphohydrolase

The properties of Mg²⁺-dependent and Mg²⁺-independent phosphatidate phosphohydrolase activities were investigated in different subcellular fractions in rat adipose tissue. Phosphatidate phosphohydrolase activity was measured in the presence of aqueous dispersed phosphatidate as substrate, and the release of inorganic phosphate was taken as a measure of phosphatidate phosphohydrolase activity. The Mg²⁺-dependent phosphatidate phosphohydrolase was inhibited in the presence of N-methyl- or N-ethylmaleimide, whereas the Mg²⁺-independent activity was unaffected by these agents. The Mg²⁺-dependent phosphatidate phosphohydrolase was more sensitive to proteolysis and to high temperature (55 °C) compared to the Mg²⁺-independent enzyme. The Mg²⁺-dependent phosphatidate phosphohydrolase activity was reduced significantly during aging without any appreciable effects on the Mg²⁺-independent phosphatidate phosphohydrolase activity. These studies demonstrate that, in addition to Mg²⁺-dependency, these two forms of phosphatidate phosphohydrolases differ in several respects irrespective of their location in the adipose cell.     

Variation of hamstrings lengths and velocities with walking speed

Crouch gait, one of the most prevalent movement abnormalities among children with cerebral palsy, is frequently treated with surgical lengthening of the hamstrings. To assist in surgical planning many clinical centers use musculoskeletal modeling to help determine if a patient’s hamstrings are shorter or lengthen more slowly than during unimpaired gait. However, some subjects with crouch gait walk slowly, and gait speed may affect peak hamstring lengths and lengthening velocities. The purpose of this study was to evaluate the effects of walking speed on hamstrings lengths and velocities in a group of unimpaired subjects over a large range of speeds and to determine if evaluating subjects with crouch gait using speed matched controls alters subjects’ characterization as having “short” or “slow” hamstrings. We examined 39 unimpaired subjects who walked at five different speeds. These subjects served as speed-matched controls for comparison to 74 subjects with cerebral palsy who walked in crouch gait. Our analysis revealed that peak hamstrings length and peak lengthening velocity in unimpaired subjects increased significantly with increasing walking speed. Fewer subjects with cerebral palsy were categorized as having hamstrings that were “short” (31/74) or “slow” (38/74) using a speed-matched control protocol compared to a non-speed-matched protocol (35/74 “short”, 47/74 “slow”). Evaluation of patients with cerebral palsy using speed-matched controls alters and may improve selection of patients for hamstrings lengthening procedures.     

1-D Metal-Dielectric-Metal Grating Structure as an Ultra-Narrowband Perfect Plasmonic Absorber in the Visible and Its Application in Glucose Detection

The need for an easy to fabricate perfect and narrowband light absorber in the visible range of electromagnetic (EM) spectrum has always been in demand for many scientific and device applications. Here, we propose a metal-dielectric-metal (MDM) 1-D grating plasmonic structure as a perfect narrow band light absorber in the visible and its application in glucose detection. The proposed structure consists of a 1- D grating of gold on the top of a dielectric layer on a gold film. Optimization for dielectric grating index (n), grating thickness (t), grating width (W), and grating period (P) has been done to improve the performance of plasmonic structure by calculating its quality factor and figure-of-merit (FOM). The optimized plasmonic structure behaves as a perfect narrowband light absorber. The flexibility to work at a specific wavelength is also offered by the proposed structure through an appropriate selection of the geometrical parameters and refractive index of the dielectric grating. The equivalent RC model is used to understand different components of the proposed structure on the optical response. The absorption response of the structure is invariant to the incident angle. Moreover, the calculated absorbance of the proposed plasmonic structure is ~ 100% with a narrow full-width half maxima (FWHM) of ~ 2.8 nm. We have numerically demonstrated a potential application of the proposed MDM absorber as a plasmonic glucose sensor in the visible range with detection sensitivity in the range of 140 to 195 nm/RIU.