Blood–Brain Transfer of Glucose and Glucose Analogs in Newborn Rats

Little is known of the selectivity of the blood-brain barrier at birth. Hexoses are transported through the barrier by a facilitating mechanism. To study the capacity of this mechanism to distinguish between analogs of D-glucose, we compared the transport of fluorodeoxyglucose, deoxyglucose, glucose, methylglucose, mannose, galactose, mannitol, and iodoantipyrine across the cerebral capillary endothelium in newborn Wistar rats. Cerebral blood flow, glucose consumption, and the blood-brain permeabilities of the hexoses were 25-50% of the adult values but the ratios between the permeabilities of the individual hexoses were similar to the ratios observed in adult rats. The mannitol clearance into brain was considerably higher than in adult rats (about 10-fold), indicating a higher endothelial permeability to small polar nonelectrolytes. The brain water content was higher in newborn than in adult rats and was associated with a higher steady-state distribution of labeled methylglucose between brain and blood. Hexose concentrations were determined relative to whole blood because the apparent erythrocyte membrane permeability to glucose was as high as in humans and thus considerably higher than in adult rats. The half-saturation concentration of glucose transport across the blood-brain barrier was considerably higher than in adult rats, about three-fold, suggesting that net blood-brain glucose transfer is less sensitive to blood glucose fluctuation in newborn than in adult rats.     

Transformation of miniature potted rose (Rosa hybrida cv. Linda) with P SAG12 -ipt gene delays leaf senescence and enhances resistance to exogenous ethylene

Key message

The P _SAG12 -ipt gene was transferred to miniature rose, as the first woody species, resulting in increased ethylene resistance due to specific up-regulation of the ipt gene under senescence promoting conditions.

Abstract

Transgenic plants of Rosa hybrida ‘Linda’ were obtained via transformation with Agrobacterium tumefaciens strain harboring the binary vector pSG529(+) containing the P _SAG12 -ipt construct. A. tumefaciens strains AGL1, GV3850 and LBA4404 (containing P_35S-INTGUS gene) were used for transformation of embryogenic callus, but transgenic shoots were obtained only when AGL1 was applied. The highest transformation frequency was 10 % and it was achieved when half MS medium was used for the dilution of overnight culture of Agrobacterium. Southern blot confirmed integration of 1–6 copies of the nptII gene into the rose genome in the tested lines. Four transgenic lines were obtained which were morphologically true-to-type and indistinguishable from Wt shoots while they were in in vitro cultures. Adventitious root induction was more difficult in transgenic shoots compared to the Wt shoots, however, one of the transgenic lines (line 6) was rooted and subsequently analyzed phenotypically. The ipt expression levels were determined in this line after exposure to exogenous ethylene (3.5 μl l^?1) and/or darkness. Darkness resulted in twofold up-regulation of ipt expression, whereas darkness combined with ethylene caused eightfold up-regulation in line 6 compared to Wt plants. The transgenic line had significantly higher content of chlorophyll at the end of the treatment period compared to Wt plants.     

Syntheses,biological evaluation and SAR of ingenol mebutate analogues for treatment of actinic keratosis and non-melanoma skin cancer

Ingenol mebutate is the active ingredient in Picato® a new drug for the treatment of actinic keratosis. A number of derivatives related to ingenol mebutate were prepared by chemical synthesis from ingenol with the purpose of investigating the SAR and potency in assays relating to pro-inflammatory effects (induction of PMN oxidative burst and keratinocyte cytokine release), the potential of cell death induction, as well as the chemical stability. By modifications of the ingenol scaffold several prerequisites for activity were identified. The chemical stability of the compounds could be linked to an acyl migration mechanism. We were able to find analogues of ingenol mebutate with comparable in vitro properties. Some key features for potent and more stable ingenol derivatives have been identified.     

Structural domains, protein modules, and sequence similarities enrich our understanding of the Shewanella oneidensis MR-1 proteome

The protein coding sequences of S. oneidensis MR-1 were analyzed, and new annotations were given to 491 gene products, 306 of which were previously of unknown function. New information was mainly brought in from structural domain predictions for S. oneidensis proteins of the SUPERFAM database (http://supfam.mrc-lmb.cam.ac.uk/SUPERFAMILY/) and newly identified and experimentally verified functions of homologous proteins. Proteins encoded by fused genes were identified and separated into modules, protein units of at least 83 aa with independent functions and distinct evolutionary histories. A reannotation of the fused gene products was done to assign functions to the appropriate module within the protein. Groups of sequence-similar proteins of S. oneidensis were assembled. The fused gene products were represented by their modular entities for the grouping process. The protein groups were analyzed for their size and functions, and they were used to indicate activities that are of importance to the environmental adaptation of this organism. Making use of several approaches not commonly used in annotation, we have been able to enrich our understanding of the functions encoded by the S. oneidensis genome.     

Liprin beta 1, a member of the family of LAR transmembrane tyrosine phosphatase-interacting proteins, is a new target for the metastasis-associated protein S100A4 (Mts1)

Metastasis-associated protein S100A4 (Mts1) induces invasiveness of primary tumors and promotes metastasis. S100A4 belongs to the family of small calcium-binding S100 proteins that are involved in different cellular processes as transducers of calcium signal. S100A4 modulates properties of tumor cells via interaction with its intracellular targets, heavy chain of non-muscle myosin and p53. Here we report identification of a new molecular target of the S100A4 protein, liprin beta1. Liprin beta1 belongs to the family of leukocyte common antigen-related (LAR) transmembrane tyrosine phosphatase-interacting proteins that may regulate LAR protein properties via interaction with another member of the family, liprin alpha1. We showed by the immunoprecipitation analysis that S100A4 interacts specifically with liprin beta1 in vivo. Immunofluorescence staining demonstrated the co-localization of S100A4 and liprin beta1 in the cytoplasm and particularly at the protrusion sites of the plasma membrane. We mapped the S100A4 binding site at the C terminus of the liprin beta1 molecule between amino acid residues 938 and 1005. The S100A4-binding region contains two putative phosphorylation sites by protein kinase C and protein kinase CK2. S100A4-liprin beta1 interaction resulted in the inhibition of liprin beta1 phosphorylation by both kinases in vitro.     

Agrobacterium tumefaciens-mediated transformation of Rhipsalidopsis gaertneri

A protocol for Agrobacterium tumefaciens-mediated genetic transformation of Rhipsalidopsis cv. CB5 was developed. Calluses derived from phylloclade explants and sub-cultured onto fresh callus induction medium over a period of 9–12 months were co-cultivated with A. tumefaciens LBA4404. Plasmid constructs carrying the nptII gene, as a selectable marker, and the reporter uidA gene were used. Transformed Rhipsalidopsis calluses with a vigorous growth phenotype were obtained by extended culture on media containing 600 mg l⁻¹ kanamycin. After 9 months of a stringent selection pressure, the removal of kanamycin from the final medium together with the culture of the transformed calluses under nutritional stress led to the formation of several transgenic adventitious shoots. Transformation was confirmed by GUS staining (for uidA gene), ELISA analysis and Southern blot hybridization (for the nptII gene). With this approach, a transformation efficiency of 22.7% was achieved. Overall results described in this study demonstrate that Agrobacterium-mediated transformation is a promising approach for this cactus species.     

Plant regeneration via somatic embryogenesis in Schlumbergera truncata

Somatic embryogenesis was induced from phylloclade explants of Schlumbergera truncata cv. Russian Dancer. Callus developed on phylloclade explants and sub-cultured over a period of 16 months on MS medium containing mainly cytokinins was superior for the induction of somatic embryos compared to callus grown for a shorter time in the establishment medium. Sub-culture of callus grown in SH-or MS-based liquid media supplemented with 7.0 μM kinetin and transferred onto solid MS-based medium with either 0.45 μM 2,4-D or without hormones resulted in the differentiation into somatic embryos. SH-based medium proved better than MS-based medium when used as the first medium for the induction of somatic embryogenesis. However, somatic embryogenesis, contrary to adventitious shoot formation, was reduced when 2,4-D was included in the MS-based medium used for final transfer compared to the medium without growth regulators, indicating that a critical hormonal balance was reached. Somatic embryos developed root and shoot poles when grown on G medium. On this medium approximately 70% germination was recorded in the embryos that were differentiated earlier from the callus that was grown for a longer time in the establishment medium. This callus was grown on either SH- or MS-based medium supplemented with 7.0 μM kinetin, and then transferred after 30 days (from SH medium) onto MS medium without hormones or after 40 days (from MS medium) onto MS medium with 0.45 μM 2,4-D. Furthermore, plants from somatic embryos were successfully potted in soil and showed further growth and formation of a second set of phylloclades (secondary phylloclades). Histological studies showed that somatic embryos had no detectable connection with the mother explants and that advanced stages of somatic embryos had a contained vascular system. In addition to the normal dicotyledonous embryos, anomalous embryos with multiple cotyledons and vase-like embryos were observed. Secondary embryos were also recorded in this study.     

1-substituted cyclopropenes: Effective Blocking Agents for Ethylene Action in Plants

A series of 1-alkane substituted cyclopropenes has been prepared and tested as ethylene antagonists using banana fruits as an assay system. 1-Methyl-, 1-ethyl-, 1-propyl-, 1-butyl-, 1-pentyl-, 1-hexyl-, 1-heptyl-, 1-octyl-, 1-nonyl-, and 1-decylcyclopropene were all very active compounds. 1-Methylcyclopropene protected bananas from ethylene with a minimum concentration of 0.7 nl.l^–1 after a 24 h exposure. As the carbon chain length was extended the minimum requirement increased some, but starting with 1-butylcyclopropene, the minimum concentration requirement declined and many cyclopropenes were required in lower concentrations than 1-methylcyclopropene. The time of protection at ambient temperature (22–23 °C) was 12 d for 1-methyl-, 1-ethyl-, 1-propyl-, and 1-butylcyclopropene. 1-Pentylcyclopropene protected bananas for 14 d, 1-hexylcyclopropene for 20 d, 1-heptylcyclopropene for 21 d, 1-octylcyclopropene for 25 d, 1-nonylcyclopropene for 35 d, and 1-decylcyclopropene for 36 d.     

Gradual Reduction in Sodium Content in Cooked Ham,with Corresponding Change in Sensorial Properties Measured by Sensory Evaluation and a Multimodal Machine Vision System

The European diet today generally contains too much sodium (Na⁺). A partial substitution of NaCl by KCl has shown to be a promising method for reducing sodium content. The aim of this work was to investigate the sensorial changes of cooked ham with reduced sodium content. Traditional sensorial evaluation and objective multimodal machine vision were used. The salt content in the hams was decreased from 3.4% to 1.4%, and 25% of the Na⁺ was replaced by K⁺. The salt reduction had highest influence on the sensory attributes salty taste, after taste, tenderness, hardness and color hue. The multimodal machine vision system showed changes in lightness, as a function of reduced salt content. Compared to the reference ham (3.4% salt), a replacement of Na⁺-ions by K⁺-ions of 25% gave no significant changes in WHC, moisture, pH, expressed moisture, the sensory profile attributes or the surface lightness and shininess. A further reduction of salt down to 1.7–1.4% salt, led to a decrease in WHC and an increase in expressible moisture.