Parenchyma cell microstructure and textural characteristics of raw and cooked potatoes

Cooking, microstructural and textural characteristics from four New Zealand potato cultivars (Agria, Nadine, Moonlight, and Red Rascal) were studied. Potatoes from the waxy cultivar, Nadine, showed lowest dry matter and starch content and also had highest cooking time compared to the other cultivars. The total colour difference, ΔE, indicative of browning and darkening during storage (for 1 h) of the peeled potatoes was observed to be highest for Red Rascal, followed by Nadine and was lowest for Agria. Light (LM) and confocal scanning electron (CSLM) micrographs revealed Moonlight and Red Rascal raw potato parenchyma cellular structure to be well integrated, showing compact hexagonal cells. Raw tubers from these cultivars also exhibited higher hardness and cohesiveness, as observed using texture profile analysis (TPA). Moonlight potato parenchyma retained cell wall outline after cooking and its cells were observed to be completely filled with gelatinised starch matrix, whereas the cellular structure of Nadine potato parenchyma was completely disintegrated after cooking. TPA results of cooked potatoes agreed well with these microstructural observations, with Moonlight cooked potatoes showing highest cohesiveness and hardness. The cell wall of parenchyma cells was observed to degrade partially upon cooking of potatoes, resulting in loosening of the cell wall microfibrils, as observed using transmission electron microscopy (TEM) of a selected potato cultivar. Also, the cell wall decreased in thickness after cooking. The remains of the primary cell wall along with some electron dense granular structures were observed floating in the cytoplasmic starchy matrix in potato tuber parenchyma cells.     

Bacterial biosurfactant in enhancing solubility and metabolism of petroleum hydrocarbons

Biosurfactant can make hydrocarbon complexes more mobile with the potential use in oil recovery, pumping of crude oil and in bioremediation of crude oil contaminant. In the investigation, bacterial isolates capable of utilizing poly-cyclic aromatic hydrocarbons like phenanthrene, pyrene and fluorene were used. A gradual decrease of the supplemented hydrocarbons in the culture medium was observed with corresponding increase in bacterial biomass and protein. The medium having the combined application of fluorine and phenanthrene caused better biosurfactant production (0.45 g l⁻¹) and (0.38 g l⁻¹) by Pseudomonas aeruginosa strains MTCC7815 and MTCC7814. The biosurfactant from MTCC7815 (41.0 μg ml⁻¹) and MTCC7812 (26 μg ml⁻¹) exhibited higher solubilization of pyrene; whereas, MTCC8165 caused higher solubilization of phenanthrene; and that of MTCC7812 (24.45 μg ml⁻¹) and MTCC8163 (24.49 μg ml⁻¹) caused more solubilzation of fluorene. Higher solubilization of pyrene and fluorene by the biosurfactant of MTCC7815 and MTCC7812, respectively enhanced their metabolism causing sustained growth. Biosurfactants were found to be lipopeptide and protein–starch–lipid complex in nature and they could reduce the surface tension of pure water (72 mN m⁻¹) to 35 mN m⁻¹. The critical micelle concentration (CMC) was also lower than the chemical surfactant sodium dodecyl sulphate (SDS). They differed in quantity and structure. The predominant rhamnolipids present in biosurfactants were Rha–C₈–C₁₀ and Rha–C₁₀–C₈.     

ISDN: ADOPTION AND DIFFUSION ISSUES

Integrated services digital network (ISDN) technology has garnered a great deal of attention but not much use. Reasons for low use include decision makers' lack of familiarity with the technology and the job of cost justification. Potential adopters of ISDN can develop effective strategies for planning and infusing this technology into their organizations if they understand the implementation issues. This article examines ISDN adoption and diffusion patterns and implementation experiences of early adopters among the Business Week 1,000 companies.     

Topical antimicrobials applied to the umbilical cord stump: a new intervention against neonatal tetanus

Primary epididymal malignancies are uncommon, and epididymal adenocarcinomas are exceedingly rare. We report a case of primary adenocarcinoma of the epididymis in a 62-year-old man and review the world literature on epididymal adenocarcinoma.     

PILOTING PEN-BASED COMPUTERS

Organizations using pilot projects to determine if pen-based technology is appropriate for their user and organizational needs were interviewed for this article. Their acceptance of pen-based computers, technology assessment techniques, and implementation experiences are discussed. The article concludes with recommendations for IS managers who plan to adopt pen-based systems, with steps to ensure support for this new technology.     

Proof for a nonproteinaceous calcium-selective channel in Escherichia coli by total synthesis from (R)-3-hydroxybutanoic acid and inorganic polyphosphate

Traditionally, the structure and properties of natural products have been determined by total synthesis and comparison with authentic samples. We have now applied this procedure to the first nonproteinaceous ion channel, isolated from bacterial plasma membranes, and consisting of a complex of poly(3-hydroxybutyrate) and calcium polyphosphate. To this end, we have now synthesized the 128-mer of hydroxybutanoic acid and prepared a complex with inorganic calcium polyphosphate (average 65-mer), which was incorporated into a planar lipid bilayer of synthetic phospholipids. We herewith present data that demonstrate unambiguously that the completely synthetic complex forms channels that are indistinguishable in their voltage-dependent conductance, in their selectivity for divalent cations, and in their blocking behavior (by La3+) from channels isolated from Escherichia coli. The implications of our finding for prebiotic chemistry, biochemistry, and biology are discussed.