Antioxidant activity of capsaicinoid in canola oil

Interest in replacing synthetic antioxidants, namely, butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA), with natural antioxidants is increasing. The present study examined the antioxidant activity of capsaicinoid from chili pepper in heated canola oil. The oxidation was conducted at 60, 90, 120, and 180 °C by monitoring oxygen consumption and the decrease in linoleic acid and α-linolenic acid in canola oil. At 60 °C, capsaicinoid was more effective against oxidation of canola oil compared with BHT. At higher temperatures of 90, 120, and 180 °C, capsaicinoid possessed an antioxidant activity similar to or slightly weaker that that of BHT. It was found that capsaicinoid prevented canola oil from oxidation in a dose-dependent manner. To study the structure-antioxidant relationship, it was found that the trimethylsiloxy (TMS) derivatives of capsaicinoid did not exhibit any antioxidant activity, suggesting the hydroxyl moiety was the functional group responsible for the antioxidant activity of capsaicinoid. It was concluded that capsaicinoid had the potential to be further explored as a natural antioxidant in foods, particularly spicy foods.     

Effect of molecular weight and concentration on crystallinity and post drawing of wet spun silk fibroin fiber

Wet spun silk fibroin (SF) filaments have attracted considerable attention because of their potential in biotechnological applications including surgical sutures, tissue engineering and wound dressing. Although the molecular weight (MW) of polymers is one of key factors affecting the wet spinnability of dope along with the structural characteristics and properties of wet spun filament, no related study has been conducted. In this study, regenerated SFs with different MWs and concentrations were prepared by wet spinning. The effects of the SF concentration and MW on 1) wet spinnability and rheology of silk dope solution and 2) crystallinity index and post drawing performance of wet spun silk filament were examined. Their relationships were also investigated. The rheological measurements showed that an 80 mPa·s viscosity is needed to obtain a continuous wet spun SF filament. As the MW of SF increased, the peak position of the maximum draw ratio shifted to a lower SF concentration with a concomitant increase in the maximum draw ratio value at the peak. Interestingly, the crystallinity index obtained from Fourier transform infrared spectroscopy (FTIR) revealed a similar trend to the maximum draw ratio suggesting that the post drawing ability is strongly affected by the quantity of short-ordered crystalline regions in wet spun SF filaments. On the other hand, X-ray diffraction did not detect any crystallinity change in the SF filament produced from the formic acid solvent system. It was concluded that MW strongly affected the dope solution viscosity and the crystallinity index from FTIR and these determined the fiber formation of dope and post drawing performance of fiber.     

Development of nanofibrous membranes with far-infrared radiation and their antimicrobial properties

This study investigated the incorporation of nanoscale germanium (Ge) and silicon dioxide (SiO₂) particles into poly(vinyl alcohol) (PVA) nanofibers with the aim of developing nanostructures with far-infrared radiation effects and antimicrobial properties for biomedical applications. Composite fibers containing Ge and SiO₂ were fabricated at various concentrations of Ge and/or SiO₂ using electrospinning and layered on polypropylene nonwoven. The morphological properties of the nanocomposite fibers were characterized using a field-emission scanning electron microscope and a transmission electron microscope. The far-infrared emissivity and emissive power of the nanocomposite fibers were examined in the wavelength range of 5-20 μm at 37 °C. The antibacterial properties were quantitatively assessed by measuring the bacterial reductions of Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. Multi-component composite fibers electrospun from 11 wt% PVA solutions containing 0.5 wt% Ge and 1 wt% SiO₂ nanoparticles exhibited a far-infrared emissivity of 0.891 and an emissive power of 3.44·102 W m^?2 with a web area density of 5.55 g m^?2. The same system exhibited a 99.9 % bacterial reduction against both Staphylococcus aureus and Escherichia coli, and showed a 34.8 % reduction of Klebsiella pneumoniae. These results demonstrate that PVA nanofibrous membranes containing Ge and SiO₂ have potential in medical and healthcare applications such as wound healing dressings, skin care masks, and medical textile products.     

Human CSF-1: molecular cloning and expression of 4-kb cDNA encoding the human urinary protein

A 4-kilobase complementary DNA (cDNA) encoding human macrophage-specific colony-stimulating factor (CSF-1) was isolated. When introduced into mammalian cells, this cDNA directs the expression of CSF-1 that is structurally and functionally indistinguishable from the natural human urinary CSF-1. Direct structural analysis of both the recombinant CSF-1 and the purified human urinary protein revealed that these species contain a sequence of at least 40 amino acids at their carboxyl termini which are not found in the coding region of a 1.6-kilobase CSF-1 cDNA that was previously described. These results demonstrate that the human CSF-1 gene can be expressed to yield at least two different messenger RNA species that encode distinct but related forms of CSF-1.     

Effects of drought stress on root morphology and spatial distribution of soybean and adzuki bean

Due to global climate change, Korea is facing severe droughts that affect the planting and early vegetative periods of upland crops. Soybean and adzuki bean are important legume crops in Korea, so it is critical to understand their adaptations to water stress. This study investigated the changes in root morphological properties in soybean and adzuki bean and quantified the findings using fractal analysis. The experiment was performed at the National Institute of Crop Science in Miryang, Korea. Soybeans and adzuki beans were planted in test boxes and grown for 30 days. The boxes were filled with bed soil with various soil moisture treatments. Root images were obtained and scanned every two days, and the root properties were characterized by root length, depth and surface area, number of roots, and fractal parameters(fractal dimension and lacunarity). Root depth, length and surface area and the number of roots increased in both crops as the soil moisture content increased. The fractal dimension and lacunarity values increased as the soil moisture content increased. These results indicated that the greater the soil moisture, the more heterogeneous the root structure. Correlation analysis of the morphological properties and fractal parameters indicated that soybean and adzuki bean had different root structure developments. Both soybean and adzuki bean were sensitive to the amount of soil moisture in the early vegetative stage. Soybean required a soil moisture content greater than 70% of the field capacity to develop a full root structure, while adzuki bean required 100% of the field capacity. These results would be useful in understanding the responses of soybean and adzuki bean to water stress and managing irrigation during cultivation.     

Extending the carbon chain: hydrocarbon formation catalyzed by vanadium/molybdenum nitrogenases

In a small-scale reaction, vanadium-dependent nitrogenase has previously been shown to catalyze reductive catenation of carbon monoxide (CO) to ethylene, ethane, propylene, and propane. Here, we report the identification of additional hydrocarbon products [α-butylene, n-butane, and methane (CH(4))] in a scaled-up reaction featuring 20 milligrams of vanadium-iron protein, the catalytic component of vanadium nitrogenase. Additionally, we show that the more common molybdenum-dependent nitrogenase can generate the same hydrocarbons from CO, although CH(4) was not detected. The identification of CO as a substrate for both molybdenum- and vanadium-nitrogenases strengthens the hypothesis that CO reduction is an evolutionary relic of the function of the nitrogenase family. Moreover, the comparison between the CO-reducing capacities of the two nitrogenases suggests that the identity of heterometal at the active cofactor site affects the efficiency and product distribution of this reaction.     

Requirement of AMPA receptor GluR2 phosphorylation for cerebellar long-term depression

Cerebellar long-term depression (LTD) is a model of synaptic memory that requires protein kinase C (PKC) activation and is expressed as a reduction in the number of postsynaptic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors. LTD was absent in cultured cerebellar Purkinje cells from mutant mice lacking the AMPA receptor GluR2 subunit and could be rescued by transient transfection with the wild-type GluR2 subunit. Transfection with a point mutant that eliminated PKC phosphorylation of Ser880 in the carboxy-terminal PDZ ligand of GluR2 failed to restore LTD. In contrast, transfection with a point mutant that mimicked phosphorylation at Ser880 occluded subsequent LTD. Thus, PKC phosphorylation of GluR2 Ser880 is a critical event in the induction of cerebellar LTD.     

Distinguishing inchworm and hand-over-hand processive kinesin movement by neck rotation measurements

The motor enzyme kinesin makes hundreds of unidirectional 8-nanometer steps without detaching from or freely sliding along the microtubule on which it moves. We investigated the kinesin stepping mechanism by immobilizing a Drosophila kinesin derivative through the carboxyl-terminal end of the neck coiled-coil domain and measuring orientations of microtubules moved by single enzyme molecules at submicromolar adenosine triphosphate concentrations. The kinesin-mediated microtubule-surface linkage was sufficiently torsionally stiff (>/=2.0 +/- 0.9 x 10(-20) Newton meters per radian2) that stepping by the hypothesized symmetric hand-over-hand mechanism would produce 180 degree rotations of the microtubule relative to the immobilized kinesin neck. In fact, there were no rotations, a finding that is inconsistent with symmetric hand-over-hand movement. An alternative "inchworm" mechanism is consistent with our experimental results.     

Molecular sorting in the secretory pathway

Proteins can be secreted from animal cells by either a constitutive or a regulated pathway; those destined for regulated secretion are actively sorted into dense-core secretory granules. Although sorting is generally assumed to be accomplished by specific carriers, the nature of these carriers remains elusive. In this study, peptide hormones were used as affinity ligands to purify a set of 25-kilodalton proteins from canine pancreatic tissue. Their ligand specificities and patterns of expression have the characteristics of sorting carriers.     

Dendritic-tree anatomy codes form-vision physiology in tadpole retina

In tadpole frog retina, the development of four classes of visual form detectors matched the growth of four types of ganglion cell dendritic trees. From this correlation of electrophysiology and anatomy we concluded that the structure of retinal ganglion cell dendritic trees provides the code for detection of visual shapes.