Highly regioselective amination of unactivated alkanes by hypervalent sulfonylimino-λ³-bromane

Amination of alkanes has generally required metal catalysts and/or high temperatures. Here we report that simple exposure of a broad range of alkanes to N-triflylimino-λ(3)-bromane 1 at ambient temperature results in C-H insertion of the nitrogen functionality to afford triflyl-substituted amines in moderate to high yields. Marked selectivity for tertiary over secondary C-H bonds was observed; primary (methyl) C-H bonds were inert. Addition of hexafluoroisopropanol to inhibit decomposition of 1 dramatically improved the C-H amination efficiencies. Second-order kinetics, activation parameters (negative activation entropy), deuterium isotope effects, and theoretical calculations suggest a concerted asynchronous bimolecular transition state for the metal-free C-H amination event.     

Artificial Infection of Rosellinia necatrix with Purified Viral Particles of a Member of the Genus Mycoreovirus Reveals Its Uneven Distribution in Single Colonies

ABSTRACT Rosellinia necatrix mycoreovirus 3 (W370) (RnMYRV-3/W370, described as RnMYRV-3 in this paper), a member of the newly established genus Mycoreovirus within the family Reoviridae, is the hypovirulence factor of the white root rot fungus, Rosellinia necatrix. Two virus-free fungal isolates (W37 and W97) that were somatically incompatible with the virus-harboring field isolate (W370) were transfected with purified RnMYRV-3 particles. Virus infection was confirmed by electrophoresis and northern hybridization of viral double-stranded RNA. RnMYRV-3 was transmissible from transfected strains to their respective, virus-free counterparts via hyphal anastomosis. Virus-transfected strains produced smaller lesions on apple fruits than did their virus-free counterparts. Virus-cured strains were indistinguishable from wild-type strains in culture morphology and displayed approximately the same virulence level on apples. Virus-transfected strains had "mosaic" colony portions consisting of thin, fast-growing and dense, slow-growing mycelia, and grew more slowly as a whole than their virus-free, parental strains. The level of virus accumulation varied among virus-transfected subcultures and within its single colonies. Virus-transfected strains were occasionally cured, as was W370. Such a phenomenon may be ascribed to uneven viral distribution in single colonies and the difficulty in viral transmission to virus-free hyphae.     

Synergistic contribution of hydrosulfide and carbonate anions to the β-O-4 bond cleavage of lignin model compounds in a green liquor pretreatment for enzymatic hydrolysis of lignocellulosic materials

To examine why green liquor (GL) pretreatment of lignocellulosic materials effectively facilitates enzymatic saccharification under conditions milder than those of a common alkaline cooking process, dimeric β-O-4 type lignin model compounds with and without free phenolic hydroxyl group were reacted in several alkaline solutions including a model solution of GL, which mainly contains Na₂CO₃ and Na₂S. The β-O-4 bond of the phenolic model compound was cleaved with a sufficient rate in the model solution of GL. The β-O-4 bond cleavage of the non-phenolic model compound was more frequent in the model solution of GL than in other alkaline solutions. These results suggest that β-O-4 bonds present in lignocellulosic materials are effectively cleaved in a GL pretreatment. It was also suggested that HS^? and CO₃ ^2? synergistically contribute to the β-O-4 bond cleavage of the non-phenolic model compound under GL pretreatment conditions.     

Epithelial cell kinetics in the inflammatory process of chicken trachea infected with infectious bronchitis virus

All stages of degeneration and regeneration in chicken tracheal epithelium were studied morphologically following an intratracheal inoculation of infectious bronchitis virus (IBV). Viral antigen was detected in the cytoplasm of tracheal epithelium from 1 to 7 days post-inoculation (d.p.i.) with a peak on 3 d.p.i. At 1 d.p.i., almost all epithelial cells were involved in the degeneration. At this time, labelling index of bromodeoxyuridine (BrdU) in the basal cells showed significantly high value compared with control. At 2 and 3 d.p.i., a great number of basal cells were recognized, but the BrdU labelling index tended to decrease. At 4 and 5 d.p.i., the BrdU labelling index of basal cells significantly decreased than 1 d.p.i., and a few number of regenerated immature ciliated epithelia appeared. At 6 to 11 d.p.i., the ciliated columnar epithelia increased rapidly in number, and returned to the normal appearance except for non-ciliated patch by 13 d.p.i. These results suggested that the tracheal epithelial cells infected with IBV degenerated within 24 hours and proliferating activity of basal cells functioned immediately, and 3 to 4 days later, these basal cells were differentiated to the ciliated epithelia.     

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blotting analyses of ureaplasmas isolated from dogs.

To define the antigenic relatedness among unspeciated ureaplasma strains isolated from dogs, four canine ureaplasma isolates representing four serotypes were compared with the five type strains of the established species in Genus Ureaplasma by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting. Although all the strains showed distinct electrophoretic patterns by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the Western blotting patterns were much more distinct. By Western blotting, the five type strains of established species reacted strongly with homologous antisera and showed slight cross reactions with heterologous antisera. However canine strains which showed little cross reactions with the established Ureaplasma species showed a variety of cross reactions among the four canine serotypes used.     

Springiness of Pancake and Its Relation to Binding of Prime Starch to Tailings in Stored Wheat Flour

Wheat flours were stored at room temperature (15–25°C), 40, 60, 80, and 100°C for various times. The baking performance of these flours was then evaluated in terms of the springiness of pancakes (recovery from crushing). Baking performance improved with increased storage time at each temperature. Brabender Amylograph tests of the flours indicated that the onset temperature in viscosity decreased with increased storage time at each temperature. When the flours were fractionated by acetic acid (pH 3.5) with mortar and pestle, recoveries of the water-solubles and gluten fractions were unchanged, but recoveries of prime starch and tailings fractions changed remarkably with increased storage time. On the other hand, those changes were not observed when flours were fractionated with a Waring blender. The binding of prime starch to tailings was correlated significantly with baking performance.     

Relationship between oxygen consumption,growth and survival of larval fish

This work aimed to evaluate the relationship between morphological development, oxygen consumption and reduced mortality in larval fish. We measured the resting metabolic rate (RM), specific metabolic rate (SMR) and the change in the total length during the larval stage of four fish species. Resting metabolism decreased from hatching to mouth opening, and then increased after mouth opening. The changes in the SMR were variable during the larval stage. After hatching, there was no increase in SMR in yolk‐sac larvae. However, SMR increased between mouth opening and the onset of notochord flexion and then decreased during notochord flexion before finally stabilizing. We observed two peaks in mortality during the larval period of all species: between mouth opening to the onset of notochord flexion and from the completion of notochord flexion to the juvenile stage based on the per cent mortality and the number of dead fish collected from the bottom of the rearing tank. Interestingly, the changes in SMR coincided with these periods of mortality. We hypothesize that larvae require more energy during these periods of larval development and are thus more susceptible to mortality when energy is insufficient. Thus, it is important to supply enough nutrition to larvae in during early development to prevent mass larval mortality.     

Effect of Initial Stocking Density on Larviculture Performance of the Ocellate Puffer,Takifugu rubripes

Depending on the initial stocking density, ocellate puffer larvae exhibit the cannibalism that resulted in high mortality. We aimed to clarify the relationship between stocking density of larvae, mortality, and the effect of density on cannibalism. Ocellate puffer larvae were reared at five different stocking densities between 5 and 25 larvae/L with duplicate 1‐m³ tank for each treatment. Larvae were stocked at 0 d after hatch (d.a.h.), and the experimental cultures lasted for 55 d. In larvae stocked initially at more than 10 larvae/L, cannibalism was evident from 11 to 17 d.a.h., and the survival rate at 55 d.a.h. was less than 15%. The survival rate was 25.5% at 5 larvae/L, and cannibalism was observed from 31 to 32 d.a.h. Consequently, an initial density of 5 larvae/L was the most efficient in terms of survival and the prevention of cannibalism. On the other hand, when cannibalism is still observed at 5 larvae/L, it is necessary to lower the stocking density before the onset of cannibalism.     

Proteolytic digestive enzyme response in Japanese flounder larvae <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis> fed two types of rotifers <Emphasis Type="Italic">Brachionus plicatilis</Emphasis> species complex

Two common live feeds, the Brachionus plicatilis species complex SS-type and L-type were used to assess whether there were any differences in protein hydrolysis and digestive trypsin activity in first feeding Japanese flounder. There were no significant differences in hydrolysis activity at 2, 3 and 7 days after hatching (DAH). At 5 DAH, hydrolysis activity was significantly higher in larvae fed SS-type (p?<?0.05) at 50 kDa in 1.5- and 3-h incubation whereas L-type treatment had not completely hydrolyzed the proteins after 3 h at the same molecular weight. Larvae fed SS-type had significantly higher (p?<?0.05) trypsin activity at 3, 5, 6, 7 DAH. Contribution of live prey to trypsin fraction in larvae showed significantly higher (p?<?0.05) fraction for SS-type at 5 DAH (2.18?±?0.44%) and 6 DAH (2.04?±?0.29%) and the effect of exogenous trypsin from live prey was relatively low when compared to the total trypsin activity in larvae. This study discusses the differences in ability to digest proteins in Japanese flounder when fed different rotifer morphotypes and highlights the adaptability of this species to alternative rotifer morphotypes during its early developmental stages.     

Reduction in the IgE reactivity of Pacific mackerel parvalbumin by mutations at Ca2+-binding sites

ABSTRACT:   Parvalbumin is a sarcoplasmic Ca²⁺-binding protein of 12 kDa and represents the major fish allergen. Several peptide segments are identified as immunoglobulin E (IgE)-binding epitopes of cod parvalbumin. However, carp parvalbumin (Cyp c 1) shows a markedly reduced IgE-binding ability upon depletion of Ca²⁺, suggesting the importance of conformational epitopes associated with Ca²⁺-chelating. In this study, the IgE reactivity of Pacific mackerel Scomber japonicus parvalbumin (Sco j 1) was demonstrated to be markedly reduced (60–100% reduction) by Ca²⁺-depletion, similar to Cyp c 1. Three Sco j 1 mutants (D51A, D90A, D51/90A), with modifications in either one or both of the two Ca²⁺-binding sites, were then constructed by site-directed mutagenesis, followed by expression in Escherichia coli , and evaluated for their IgE reactivity. Interestingly, the double mutant (D51/90A), probably devoid of Ca²⁺-binding capacity, exhibited a significantly reduced IgE reactivity (equivalent to 0.0–7.5% of the IgE reactivity of natural Sco j 1). The results suggest that the IgE-binding ability of Sco j 1 largely depends on the solid conformation mediated by Ca²⁺-chelating, and that the hypoallergenic D51/90A will be a useful tool for the specific immunotherapy of fish allergy.