Dual perfluorocarbon method to noninvasively monitor dissolved oxygen concentration in tissue engineered constructs in vitro and in vivo

Noninvasive in vivo monitoring of tissue implants provides important correlations between construct function and the observed physiologic effects. As oxygen is a key parameter affecting cell and tissue function, we established a monitoring method that utilizes ¹⁹F nuclear magnetic resonance (NMR) spectroscopy, with perfluorocarbons (PFCs) as oxygen concentration markers, to noninvasively monitor dissolved oxygen concentration (DO) in tissue engineered implants. Specifically, we developed a dual PFC method capable of simultaneously measuring DO within a tissue construct and its surrounding environment, as the latter varies among animals and with physiologic conditions. In vitro studies using an NMR‐compatible bioreactor demonstrated the feasibility of this method to monitor the DO within alginate beads containing metabolically active murine insulinoma βTC‐tet cells, relative to the DO in the culture medium, under perfusion and static conditions. The DO profiles obtained under static conditions were supported by mathematical simulations of the system. In vivo, the dual PFC method was successful in tracking the oxygenation state of entrapped βTC‐tet cells and the surrounding peritoneal DO over 16 days in normal mice. DO measurements correlated well with the extent of cell growth and host cell attachment examined postexplantation. The peritoneal oxygen environment was found to be variable and hypoxic, and significantly lower in the presence of metabolically active cells. The significance of the dual PFC system in providing critical DO measurements for entrapped cells and other tissue constructs, in vitro and in vivo, is discussed. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011     

Genetic variation of growth and tree quality traits among 42 diverse genetic origins of Tectona grandis planted under humid tropical conditions in Sabah, East Malaysia

Forty-two different genetic origins of teak (Tectona grandis) comprising 26 open-pollinated families from a clonal seed orchard (CSO) were planted in a replicated trial under 2,500 mm of annual rainfall and no distinct dry season, in 1997, in Sabah, East Malaysia. The trees were measured or scored for various traits at 13, 35, 49, 61, 72, 85, 96, and 106 months after planting. Mortality rate, height (H), diameter at breast height (DBH), volume (V), and fork height (FH) varied strongly among populations and origins. The best population means after 106 months for growth H (21.1 m), DBH (21.1 cm), and V (278 dm³) were for the CSO families. Narrow sense heritabilities for the CSO families increased gradually with age but remained lower after 106 months for DBH (h ² = 0.24) and V (h ² = 0.34) than for H (h ² = 0.51) and FH (h ² = 0.56). Overall, the CSO families were also straighter, less forked, and grew more vertically than the native provenance and seed-derived sources. Such differences did not exist for flowering ability, and at 106 months, the great majority of the trees of the various origins had not yet entered the flowering stage. Overall, at 106 months, the phenotypic correlations between the various quantitative and qualitative traits were weak, except between straightness and bending with values higher than 0.50. These findings confirm the usefulness of CSO for teak improvement and demonstrate the beneficial influence of wet tropical conditions on traits of major economical importance for this species.     

Growth-promoting effects of lactoferrin on L. acidophilus and Bifidobacterium spp.

We investigated the effects of lactoferrin on the growth of L. acidophilus CH-2, Bifidobacterium breve ATCC 15700, B. longum ATCC 15707, B. infantis ATCC 15697, and B. bifidum ATCC 15696. The growth of L. acidophilus was stimulated by bovine holo-lactoferrin but not by apo-lactoferrin. With bifidobacteria, bovine lactoferrin stimulated growth of three strains: B. breve, B. infantis and B. bifidum under certain conditions. Both apoprotein and holoprotein had similar effects. However, B. longum growth was not affected by lactoferrin. Thus, the mechanism of stimulating growth of bifidobacteria may be different from that of L. acidophilus. By far-western blotting using biotinylated lactoferrin and horseradish peroxidase-conjugated streptavidin, lactoferrin-binding proteins were detected in the membrane protein fraction of L. acidophilus, B. bifidum, B. infantis and B. breve. The molecular weights of lactoferrin-binding proteins of L. acidophilus were estimated from SDS-polyacrylamide gel electrophoresis to be 27, 41 and 67 kDa, and those of the three bifidobacterial strains were estimated to be 67-69 kDa. However, no such lactoferrin-binding components were detected in the membrane fraction of B. longum. It is interesting that the appearance of lactoferrin-binding proteins in the membrane fraction of these species corresponds to their growth stimulation by lactoferrin.     

Assessment of alcohol percentage test for fungal surface hydrophobicity measurement

Aim: To determine whether assessing the penetration of solutions with different concentrations of ethanol (alcohol percentage test: APT) on fungal surfaces is effective in characterization of hydrophobicity on fungal surfaces. Methods and Results: APT and contact angle (CA) measurements were conducted on nine hydrophobic and two hydrophilic fungal strains from the phyla of Ascomycota, Basidiomycota and Zygomycota. There was a strong positive correlation (R² = 0·95) between the APT and CA measurements from eight of the nine hydrophobic stains (four pathogenic and mycotoxigenic Fusarium taxa, one melanosporaceous biotrophic taxon, Alternaria sp, Penicillium aurantiogriseum and Cladosporium cladosporioides). Hydrophilic control strains, Mortierella hyalina and Laccaria laccata, had CAs <90° and no measurable degree of hydrophobicity using the APT method. Conclusions: The APT method was effective in measuring the degree of hydrophobicity and can be conducted on different zones of fungal growth. Significance and Impact of the Study: Characterization of fungal surface hydrophobicity is important for understanding of its particular role and function in fungal morphogenesis and pathogenesis. APT is a simple method that can be utilized for fungal hydrophobicity measurements when CA cannot be measured because of obscured view from aerial mycelia growth.     

AKTIP interacts with ESCRT I and is needed for the recruitment of ESCRT III subunits to the midbody

To complete mitosis, the bridge that links the two daughter cells needs to be cleaved. This step is carried out by the endosomal sorting complex required for transport (ESCRT) machinery. AKTIP, a protein discovered to be associated with telomeres and the nuclear membrane in interphase cells, shares sequence similarities with the ESCRT I component TSG101. Here we present evidence that during mitosis AKTIP is part of the ESCRT machinery at the midbody. AKTIP interacts with the ESCRT I subunit VPS28 and forms a circular supra-structure at the midbody, in close proximity with TSG101 and VPS28 and adjacent to the members of the ESCRT III module CHMP2A, CHMP4B and IST1. Mechanistically, the recruitment of AKTIP is dependent on MKLP1 and independent of CEP55. AKTIP and TSG101 are needed together for the recruitment of the ESCRT III subunit CHMP4B and in parallel for the recruitment of IST1. Alone, the reduction of AKTIP impinges on IST1 and causes multinucleation. Our data altogether reveal that AKTIP is a component of the ESCRT I module and functions in the recruitment of ESCRT III components required for abscission.     

Life expectancy of oil palm (Elaeis guineensis) infected by Ganoderma boninense in coastal soils,Malaysia: a case study

Ganoderma boninense basal stem rot poses a serious threat to the oil palm industry. The effects of external disease symptoms and coastal soils (Briah – Typic Endoaquepts, Jawa – Typic Sulfaquepts, and Selangor – Typic Humaquepts) on the life expectancy of the infected palms, from disease detection to death, were studied. Six-monthly censuses on disease classes for each palm were recorded between 2004 and 2012. Survival curves of disease symptoms and soil types were compared using Kaplan–Meier and log-rank methods, respectively. Ganoderma-infected palms in acid-sulphate (AS) and potential AS soils recorded lower life expectancy. Survival duration of infected palms with foliar symptoms was 12-months shorter. External factors, such as soil type may influence the survival of infected palms and soil types may pre-dispose oil palm to higher risk of Ganoderma infection. More effective Ganoderma management for palms planted on Coastal soils (with and without AS layer) have been proposed.