Behavior of histamine-producing bacteria in shimesaba, raw mackerel salted and marinated in vinegar during processing and storage at various temperatures

To study the behavior of histamine-producing bacteria during the processing and storage of shimesaba, we inoculated histamine-producing bacteria into raw mackerel and then evaluated bacterial counts and histamine content at each shimesaba processing step. Six histamine-producing bacteria—Morganella morganii, Enterobacter aerogenes, Raoultella planticola, Photobacterium damselae (2 strains), and Photobacterium phosphoreum—were inoculated onto the surface of mackerel fillets at various cell densities (no inoculation, 10⁴, and 10⁷ cfu ml^?1). The fillets were then treated according to the common procedure used for processing shimesaba. The concentration of NaCl in brine during the salting procedure was 10 % (w/v), and the main ingredients of the marinade broth were 27 % vinegar, 3.8 % sucrose, 0.3 % sodium glutamate, and 0.1 % sodium succinate. The level of histamine-producing bacteria and of histamine did not increase during the salting and marinating procedures. However, during the storage tests, histamine content increased remarkably in the shimesaba products stored at 10 °C for 3 days, and organoleptical degradation was also observed. However, significant deterioration, based on bacterial count, histamine content, and organoleptic evaluation, was not observed in samples stored at 5 °C. These results indicate that the use of traditional marinade broth during the processing of shimesaba and storage below 5 °C are effective methods for preventing histamine accumulation.     

Identification and primary structures of eel type I collagen proα1, proα2 and proα3

Many bony fish type I collagens have a characteristic third chain designated as α3(I). However, much less is known about the primary structure and distinction of the proα(I) chains. Their cDNAs were cloned by RT-PCR from the muscle tissue of Japanese eel, Anguilla japonica. Three cDNAs coding for the triple-helical domain of fibrillar collagen were identified as proα1(I), proα2(I) and proα3(I) chains by sequencing selected tryptic peptides isolated from eel type I collagen subunit chains, α1(I), α2(I) and α3(I). Eel proα3(I) had high amino acid sequence identity (81 %) to its proα1(I). The distribution of seven Cys residues in the C-propeptide of proα3(I) was identical to that of proα1(I). There was a third Cys residue at the 1,268th position from the N-terminus in proα1(I), though a supposed Cys residue at the 1,264th position in proα3(I) was replaced by a Ser residue. Similar replacement has been observed in the proα3(I) chains of trout and zebrafish. These combined results suggest that replacement of the Cys residue allows for the identification of fish collagen proα(I) previously not identified as proα3(I).     

Phenotypic characterization and cultivation conditions of inhibitor-producing fungus isolated from marine sediment

ABSTRACT:   Tyrosinase inhibitor-producing fungus of Trichoderma sp. strain H1-7, which was isolated from marine sediment, was investigated by phylogenetic analysis and physiological characteristics. Phylogenetic analyses of the strain were similar to Trichoderma atroviride or T. viride . Physiological characteristics of the strain were similar to T. viride , and based on these results, it was identified as T. viride . Characterization of tyrosinase inhibitory activity of a culture supernatant of the strain was investigated. The inhibitory activity of the supernatant of the strain decreased after cultivation for more than 3 days. Furthermore, sea water was not essential for the production of the tyrosinase inhibitor (TI). When TI production of the strain was compared to T. viride , the strain showed higher activity than T. viride . From this result, it seemed that the strain had characteristic features comparable to T. viride , which was isolated from the terrestrial environment. As TI production of the strain showed higher potential than that of T. viride , it is necessary to elucidate the chemical structure of TI exemplified in the present study.     

Tannic acid and Norway spruce condensed tannins can precipitate various organic nitrogen compounds

There is increasing evidence that tannins affect degradation of soil organic matter and nitrogen cycling. It is assumed that the influence of tannins on biochemical processes is partly related to their ability to precipitate proteins. However, there is almost no information about precipitation of organic nitrogen-containing compounds other than proteins. A few studies indicate that tannins can precipitate arginine, choline or chitosan. In this study we used commercial tannic acid and condensed tannins extracted from Norway spruce (Picea abies (L.) Karst) needles to investigate precipitation of a wide range of organic nitrogen compounds including amino acids (all 20 proteinaceous), peptides (insulin, oxidized glutathion, reduced glutathion, AlaAla, GlyGlu, GlyPhe, GlyGlyGly), proteins (bovine serum albumin, Rubisco i.e. d-ribulose 1,5-diphosphate carboxylase), nitrogen bases, polyamines and aminosugars (N-acetyl-d-glucosamine, chitin and chitosan). Our results showed that tannins can precipitate a subset of these compounds - of the amino acids only arginine, of the peptides studied only insulin, all the proteins, polyamines, nitrogen bases, chitin and chitosan, but not N-acetyl-d-glucosamine. Concentrations of organic nitrogen compound and tannins affected amount of these compounds in precipitates. Moreover, pH value affected precipitation. The amount of precipitated organic nitrogen compound and the amount of precipitated tannins showed positive correlation across different pH. Precipitation of organic N-containing compounds other than protein by tannins can potentially affect reactions in all biochemical mixtures including tannins and these organic nitrogen compounds, and affect soil N cycling.     

Influence of diterpenes (colophony and abietic acid) and a triterpene (beta-sitosterol) on net N mineralization,net nitrification,soil respiration,and microbial biomass in birch soil

The aim of this study was to examine the effect of common diterpenes (colophony, abietic acid) and triterpene (beta-sitosterol) on carbon (C) and nitrogen (N) transformations in soil under birch (Betula pendula L.). Samples were taken from the organic layer at two study sites, Kivalo (N-poor soil) and Kerimäki (N-rich soil), and incubated with the above-mentioned terpenes in laboratory conditions. Carbon dioxide evolution (C mineralization), net N mineralization, nitrification, and N and C in microbial biomass were measured. All these terpenes increased C mineralization, but decreased net N mineralization. The potential to decrease net N mineralization depended on amount of terpenes, with a stronger effect at a higher amount. Net nitrification in Kerimäki soil (N-rich soil) decreased but was not completely inhibited by terpenes. Effect of terpenes on soil microbial biomass C and N was not so clear, but they tended to increase both. Our study suggests that higher terpenes can act as a carbon source for soil microbial communities.     

Expressions of protein oxidation markers, dityrosine and advanced oxidation protein products in Cisplatin-induced nephrotoxicity in rats

The purpose of this study was to evaluate whether dityrosine and advanced oxidation protein products (AOPP) reflect the severity of cisplatin-induced nephrotoxicity. Immunoexpression of dityrosine in kidneys and plasma AOPP concentration were examined up to day 4 post-cisplatin injection in rats. Cisplatin injection induced tubular injury on days 2-4 after injection and increased serum creatinine and BUN on days 3 and 4. On days 2-4, dityrosine was immunostained in the cytoplasm of damaged tubular cells, and their immunostaining intensity increased time-dependently. Plasma AOPP levels were significantly increased on days 3 and 4. These results suggest that expressions of dityrosine and AOPP were associated with the severity of renal injury and may be useful markers for the development of cisplatin-induced nephrotoxicity.     

Properties of dissolved organic matter derived from silver birch and Norway spruce stands: Degradability combined with chemical characteristics

Dissolved organic matter (DOM) derived from the humus layer under silver birch (Betula pendula Roth), Norway spruce (Picea abies (L.) Karst.), and mixed stands, and from senescent birch leaves and from spruce needles of the four oldest year-growth were characterized microbiologically and chemically. Samples were collected in the autumn and the solutions were obtained by centrifugation-drainage technique. The degradability of DOM, the availability of DOM to bacteria and fungi, concentrations of phenolic compounds and carbohydrates, and the distribution of carbon and nitrogen into fractions according to the chemical nature and the molecular size were studied. DOM derived from leaves and needles was clearly more labile than DOM derived from the humus layer indicating the importance of studying the DOM originating from fresh litter when assessing the turnover of DOM.DOM derived from spruce needles appeared to differ chemically greatly from all other samples. It had very high concentrations of carbohydrates, probably due to the sampling time, and phenolic compounds. The chemical composition of DOM derived from humus layer did not reflect the composition of DOM derived from needles and leaves. DOM derived from birch leaves degraded more than DOM derived from spruce needles and DOM derived from humus layer collected at the birch sites degraded more than DOM derived from humus layer collected at the spruce sites. The degradability of different compound groups of DOC and DON was studied in a short-term incubation (20 d) of DOM solutions by characterizing the solutions initially and after the incubation. Almost all compound groups appeared to degrade but weak hydrophobic acids, bases, hydrophilic neutrals, the smallest molecular size compounds, carbohydrates, and phenolic compounds degraded the most.     

Three‐dimensional CT observation of position and movability of the scapula in the horse using carcasses of Falabella

The three‐dimensionally real position and movement of the scapula in the lateral side of the ribcage could not be clarified in the horse, since the body size of the horse is too large to apply the CT scanning and image analysis methods. In this study, therefore, we examined the position and the movability of scapula using a carcass of the Falabella which is one of the smallest breeds of the horse. The whole skeletal system in thoracic part of the Falabella could be three‐dimensionally observed by CT scanning method. The three‐dimensional images show that the scapula cranially slides and the ventral part of the scapula dorso‐cranially rotates, when the shoulder joint moves to the most cranial position as simulation. The three‐dimensional rotation angle was approximately 10 degrees. As a result of comparative osteology of the scapula between Falabella and the large draft horse, the infraspinous fossa was caudally enlarged in the larger draft horse, whereas the Falabella had narrower infraspinous fossa. We suggest that it may be due to the adaptational morphological change in the scapula bearing various body weights among breeds. The three‐dimensional CT image analysis and the simulation in carcass contribute to the analysis of the bone movements of the horse during walking and running locomotion as well as the motion analysis from external functional‐morphological data.     

Comparative studies on the photosynthesis of higher plants

1) CO₂ compensation points of the plants tested correlate well with the leaf anatomy. Low CO₂ compensation plants had well-developed VBS containing large and specialized chloroplasts but no plant with a high CO₂ compensation point possessed chloroplasts in the VBS.

2) CO₂ Compensation Points Closely Correlated With The Major Carboxylation Pathway In Photosynthesis. Low Compensation Plants Fixed CO₂ Via The C-4 Pathway (C-4 Plants) While High Compensation Plants Carried Out CO₂ Fixation By The Calvin Cycle (C-3 Plants).

3) Close correlations could be established for the CO₂ compensation point, the major carboxylation pathway, and glycolate oxidase activity. Glycolate oxidase activity was much higher in C-3 plants than in C-4 plants. On the other hand, dark respiration in C-4 plants was higher than that in C-3 plants.

4) TCA cycle activity in detached leaves was not inhibited to any large extent by illumination.

In C-3 plants, the release of ¹⁴CO₂ from alanine-1-¹⁴C increased with an increase in the ambient O₂ concentration; whereas, radioactivity in the sugar fraction was quite small at all O₂ concentrations. In C-4 plants the release of ¹⁴CO₂ was little affected by the ambient O₂ concentration while sugar formation was stimulated at high O₂ concentrations. This indicates that in C-3 plants CO₂ fixation is blocked at a high O₂ concentration, therefore, internal ¹⁴CO₂ is released from the leaf without being refixed, but in C-4 plants internal ¹⁴CO₂ can be efficiently refixed and metabolized to sugar by a combination of active PEP carboxylase and the ‘Kranz type’ of leaf anatomy.     

添加青稞酒糟对西藏地区青稞秸秆和高羊茅混合青贮发酵品质的影响

 ：为评价添加不同水平青稞酒糟对青稞秸秆与高羊茅（４∶６）混合青贮发酵品质的影响,试验设对照组（Ｃｏｎｔｒｏｌ）和３个添加水平（１０％,２０％和３０％）的青稞酒糟处理组,青贮后第７,１４和３０天后打开青贮窖,测定青贮饲料发酵品质。结果表明,添加青稞酒糟可以抑制青贮早期好氧性微生物的活性,促进乳酸发酵,使ｐＨ 值快速下降,青贮饲料快速进入稳定阶段。青贮３０ｄ后,与对照组相比酒糟处理显著降低（P＜０．０５）了青贮饲料的ｐＨ 值,提高了乳酸和水溶性碳水化合物含量,降低了（P＜０．０５）氨态氮／总氮及丙酸和丁酸含量。综合考虑,添加２０％ 酒糟效果更佳。