Identification of two novel amyloid A protein subsets coexisting in an individual patient of AA-amyloidosis

Amyloid A protein (AA), the major fibril protein in AA-amyloidosis, is an N-terminal cleavage product of the precursor protein, serum amyloid A (SAA). Using mass spectrometry and amino-acid sequencing, we identified and characterized two novel AA protein subsets co-deposited as amyloid fibrils in an patient having AA-amyloidosis associated with rheumatoid arthritis. One of the AA proteins corresponded to positions 2–76 (or 75) of SAA2α and the other corresponded to positions 2–76 (or 75) of known SAA1 subsets, except for position 52 or 57, where SAA1α has valine and alanine and SAA1β has alanine and valine in position 52 and 57, respectively, whereas the AA protein had alanine at the both positions. Our findings (1), demonstrate that not only one but two SAA subsets could be deposited together as an AA-amyloid in a single individual and (2), support the existence of a novel SAA1 allotype, i.e., SAA1^52,57Ala.     

Production of saikosaponins by tissue culture of Bupleurum falcatum L.

The studies for production of saikosaponins by tissue culture of Bupleurum falcatum L. were carried out to produce saikosaponins with several kinds of media and plant hormones. Among the media and plant hormones studied, Gamborg's B-5 [23] medium containing 0.5 ppm kinetin (k) and 1.0 ppm 3-indolebutyric acid (IBA) was the most effective medium and hormone for production of saikosaponins. The highest content of saikosaponin-d in the dried cells was 0.26%, which was similar to a concentration of Bupleuri Radix.Abbreviations MS medium used by Murashige and Skoog [22] - G medium used by Gamborg (B 5) [23] - W medium used by White [24] - NN medium used by Nitsch and Nitsch [25] - k Kinetin - BAP 6-Benzylaminopurine - 2,4 D 2,4-Dichlorophenoxyacetic acid - NAA -Naphtylacetic acid - IBA 3-Indolebutyric acid - IAA 3-Indoleacetic acid - ssd saikosaponin-d - PM Production medium - dw Dry weight     

Examination of the method for measuring soil respiration in cultivated land: Effect of carbon dioxide concentration on soil respiration

An acceleration of soil respiration with decreasing CO₂ concentration was suggested in the field measurements. The result supporrs that obtained in laboratory experiments in our previous study. The CO₂ concentrations in a chamber of the alkali absorption method (the AA-method) were about 150–250 parts/10⁶ lower than that in the atmosphere (about 350 parts/10⁶), while those observed in the open-flow IRGA method (the OF-method) were nearly equal to the soil surface CO₂ levels. The AA-method at such low CO₂ levels in the chamber appears to overestimate the soil respiration. Our results showed that the rates obtained by the AA-method were about twice as large as those by the OF-method in field and laboratory measurements. This finding has important consequences with respect to the validity of the existing data obtained by the AA-method and the estimation of changes in the terrestrial carbon flow with elevated CO₂     

REPRODUCTIVE ISOLATION BY HOST SPECIFICITY IN A PAIR OF PHYTOPHAGOUS LADYBIRD BEETLES

Crossing experiments and food-choice tests show that two sympatric species of phytophagous ladybird beetles, Epilachna niponica and E. yasutomii, are reproductively isolated by host-plant specificity. Adult beetles selected their natural hosts when given choices, though some accepted the host of the other species when no choice was offered. In each species, survival of larvae to the second instar was significantly higher on their own host plant. No evidence for sexual isolation, gametic isolation, hybrid inviability, or reduced hybrid fertility was detected. Reproductive isolation by host specificity is an important prerequisite for certain models of sympatric speciation. Although the present example supports the plausibility of such models, an allopatric origin of host-plant specificity cannot be discounted.     

Productivity and mineral cycling in an oak coppice forest 2. Annual net production of the forest

Annual net production was estimated in the secondary coppice forest near Tokyo, which was dominated by a deciduous oak,Quercus serrata Thunb. Lateral growth of stems and old branches was directly estimated by examining the annual rings for 35 shoots in a clear-cut quadrat of 10m×10m. Phytomasses of current organs were also weighed in the quadrat. Preharvest losses of current organs were determined by twelve 0.5 m² litter traps for fine litter and twelve 6 m² quadrats for woody litter. Branch production was also assessed indirectly by use of the stem-branch allometry and death of branches. The results of the indirect method were in sufficient agreement with the result of the direct one. Grazing loss of leaves from the canopy was estimated directly from the loss in leaf area and indirectly from the animal faeces caught by the litter traps. Net production of the canopy trees was 149 kg a⁻¹ year⁻¹, in which leaf production was 36.9 kg. Animals grazed about 14% of the leaf area by the end of the growing season. True consumption of leaves by animals was 7.6% of leaf production or 10% of leaf mass. Production of undergrowth, mainly a dwarf bamboo,Pleioblastus chino Makino, was 28 kg a⁻¹ year⁻¹, being 15% of the total stand production. Productivity of this forest was significantly higher than that of cool-temperate deciduous broadleaf forests.     

Late Quaternary Environmental and Human Impacts on the Mitochondrial DNA Diversity of Four Commensal Rodents in Myanmar

Journal of Mammalian Evolution - We addressed the spatiotemporal characteristics of four commensal rodent species occurring in Myanmar in comparison with other areas of the Indo-Malayan region. We...     

Reductive Dechlorination of 1,2,4-Trichlorobenzene by Staphylococcus epidermidis Isolated from Intestinal Contents of Rats

Twelve bacterial strains which were concerned with dechlorination of 1,2,4-trichlorobenzene (TCB) were isolated from the intestinal contents of rats and it was found that they belonged to Staphylococcus epidermidis (strain A-F), Staphylococcus saprophyticus (strain G), Streptococcus sp. (strains H and I), Bacillus sp. (strain J), Gram negative rod (strain K) and Lactobacillus sp. (strain L).

In Staphylococcus epidermidis (Strain A), TCB was mainly converted to o-dichlorobenzene and the latter was preferentially converted to monochlorobenzene (MCB) among dichlorobenzenes (DCBs). These conversions proceeded only under a gas phase of hydrogen. Furthermore, dry and broken cells of intact bacteria also maintained the dechlorinating activities, which were stimulated by the addition of NADPH.

Therefore, it was supposed that the conversion of TCB to MCB via DCBs was reductively carried out by enzymes originating from the isolated bacteria.     

Involvement of luxS in Biofilm Formation by Capnocytophaga ochracea

Capnocytophaga ochracea is present in the dental plaque biofilm of patients with periodontitis. Biofilm cells change their phenotype through quorum sensing in response to fluctuations in cell-population density. Quorum sensing is mediated by auto-inducers (AIs). AI-2 is involved in intercellular signaling, and production of its distant precursor is catalyzed by LuxS, an enzyme involved in the activated methyl cycle. Our aim was to clarify the role of LuxS in biofilm formation by C. ochracea. Two luxS-deficient mutants, TmAI2 and LKT7, were constructed from C. ochracea ATCC 27872 by homologous recombination. The mutants produced significantly less AI-2 than the wild type. The growth rates of these mutants were similar to that of the wild-type in both undiluted Tryptic soy broth and 0.5 × Tryptic soy broth. However, according to crystal violet staining, they produced significantly less biofilm than the wild type. Confocal laser scanning microscopy and scanning electron microscopy showed that the biofilm of the TmAI2 strain had a rougher structure than that of the wild type. Complementation of TmAI-2 with extrinsic AI-2 from the culture supernatant of wild-type strain did not restore biofilm formation by the TmAI2 strain, but complementation of LKT7 strain with luxS partially restored biofilm formation. These results indicate that LuxS is involved in biofilm formation by C. ochracea, and that the attenuation of biofilm formation by the mutants is likely caused by a defect in the activated methyl cycle rather than by a loss of AI-2.     

Fluorescent substrates for ADAM15 useful for assaying and high throughput screening

A disintegrin and metalloproteinase 15 (ADAM15), also known as metargidin, plays important roles in regulating inflammation, wound healing, neovascularization, and is an attractive drug target. Fluorescence resonance energy transfer (FRET)-based peptide substrates were tested to identify candidate reagents for high throughput screening and detection of ADAM15 in biological samples. ADAM15 exhibits a unique and diverse activity profile compared to other metalloproteinases. Two FRET substrates, Dabcyl-Gly-Pro-Leu-Gly-Met-Arg-Gly-Lys(FAM)-NH2 (PEPDAB011) and Dabcyl-Ala-Pro-Arg-Trp-Ile-Gln-Asp-Lys(FAM)-NH2 (PEPDAB017), which also detect activities of several matrix metalloproteinases (MMPs −2, –9, and −13), were efficiently cleaved by ADAM15 with specificity constants of 5800 M⁻¹ s⁻¹ and 4300 M⁻¹ s⁻¹, respectively. Additionally, ADAM15 efficiently processed Dabcyl-Leu-Arg-Glu-Gln-Gln-Arg-Leu-Lys-Ser-Lys(FAM)-NH2 (PEPDAB022), which is based on a physiological CD23 cleavage site, with a specificity constant (k_cat/K_m) of 5200 M⁻¹ s⁻¹. PEPDAB022 was used to screen the ability of known metalloproteinase inhibitors including TAPI-2, marimastat, GI-254023, and the Tissue Inhibitor of Metalloproteinases(TIMPs) 1 and 3 to block ADAM15 activity. Even though ADAM15 exhibits similar substrate preferences to other metalloproteinases, many broad spectrum inhibitors failed to block ADAM15 activity at concentrations as high as 50 μM. Thus, a clear need exists to develop potent and selective ADAM15 inhibitors, and the FRET substrates described herein should aid future research efforts towards this aim.     

Assessment of a large number of empirical plant species niche models by elicitation of knowledge from two national experts

Quantitative models play an increasing role in exploring the impact of global change on biodiversity. To win credibility and trust, they need validating. We show how expert knowledge can be used to assess a large number of empirical species niche models constructed for the British vascular plant and bryophyte flora. Key outcomes were (a) scored assessments of each modeled species and niche axis combination, (b) guidance on models needing further development, (c) exploration of the trade‐off between presenting more complex model summaries, which could lead to more thorough validation, versus the longer time these take to evaluate, (d) quantification of the internal consistency of expert opinion based on comparison of assessment scores made on a random subset of models evaluated by both experts. Overall, the experts assessed 39% of species and niche axis combinations to be “poor” and 61% to show a degree of reliability split between “moderate” (30%), “good” (25%), and “excellent” (6%). The two experts agreed in only 43% of cases, reaching greater consensus about poorer models and disagreeing most about models rated as better by either expert. This low agreement rate suggests that a greater number of experts is required to produce reliable assessments and to more fully understand the reasons underlying lack of consensus. While area under curve (AUC) statistics showed generally very good ability of the models to predict random hold‐out samples of the data, there was no correspondence between these and the scores given by the experts and no apparent correlation between AUC and species prevalence. Crowd‐sourcing further assessments by allowing web‐based access to model fits is an obvious next step. To this end, we developed an online application for inspecting and evaluating the fit of each niche surface to its training data.