• Journal of Microbiology and Biotechnology
• /
• v.30 no.7
• /
• pp.996-1004
• /
• 2020

Various genetically engineered microorganisms have been developed for the removal of heavy metal contaminants. Metal biosorption by whole-cell biosorbents can be enhanced by overproduction of metal-binding proteins/peptides in the cytoplasm or on the cell surface. However, few studies have compared the biosorption capacity of whole cells expressing intracellular or surface-displayed metal-adsorbing proteins. In this study, several constructs were prepared for expressing intracellular and surface-displayed Ochrobactrum tritici 5bvl1 ChrB in Escherichia coli BL21(DE3) cells. E. coli cells expressing surface-displayed ChrB removed more Cr(VI) from aqueous solutions than cells with cytoplasmic ChrB under the same conditions. However, intracellular ChrB was less susceptible to variation in extracellular conditions (pH and ionic strength), and more effectively removed Cr(VI) from industrial wastewater than the surface-displayed ChrB at low pH (<3). An adsorption-desorption experiment demonstrated that compared with intracellular accumulation, cell-surface adsorption is reversible, which allows easy desorption of the adsorbed metal ions and regeneration of the bioadsorbent. In addition, an intrinsic ChrB protein fluorescence assay suggested that pH and salinity may influence the Cr(VI) adsorption capacity of ChrB-expressing E. coli cells by modulating the ChrB protein conformation. Although the characteristics of ChrB may not be universal for all metal-binding proteins, our study provides new insights into different engineering strategies for whole-cell biosorbents for removing heavy metals from industrial effluents.

• Journal of Microbiology and Biotechnology
• /
• v.33 no.10
• /
• pp.1370-1375
• /
• 2023

In this study, we aimed to enhance the accumulation of chorismate (CHR) and anthranilate (ANT), key intermediates in the shikimate pathway, by modifying a shikimate over-producing recombinant strain of Corynebacterium glutamicum [19]. To achieve this, we utilized a CRISPR-driven genome engineering approach to compensate for the deletion of shikimate kinase (AroK) as well as ANT synthases (TrpEG) and ANT phosphoribosyltransferase (TrpD). In addition, we inhibited the CHR metabolic pathway to induce CHR accumulation. Further, to optimize the shikimate pathway, we overexpressed feedback inhibition-resistant Escherichia coli AroG and AroH genes, as well as C. glutamicum AroF and AroB genes. We also overexpressed QsuC and substituted shikimate dehydrogenase (AroE). In parallel, we optimized the carbon metabolism pathway by deleting the gntR family transcriptional regulator (IolR) and overexpressing polyphosphate/ATP-dependent glucokinase (PpgK) and glucose kinase (Glk). Moreover, acetate kinase (Ack) and phosphotransacetylase (Pta) were eliminated. Through our CRISPR-driven genome re-design approach, we successfully generated C. glutamicum cell factories capable of producing up to 0.48 g/l and 0.9 g/l of CHR and ANT in 1.3 ml miniature culture systems, respectively. These findings highlight the efficacy of our rational cell factory design strategy in C. glutamicum, which provides a robust platform technology for developing high-producing strains that synthesize valuable aromatic compounds, particularly those derived from the shikimate pathway metabolites.

• Food Science and Biotechnology
• /
• v.27 no.6
• /
• pp.1843-1856
• /
• 2018

Tea is one of the most frequently consumed drinks due to its favourite taste and the health benefit. Tea is produced by several processes and drying is very important step to develop the flavour and destroys the enzymes in tea. However, during drying tea, polycyclic aromatic hydrocarbons some of which are carcinogen and genotoxin are naturally produced. The risk of PAHs by drinking tea was characterized by determining contents of 4 PAHs in tea. 4 PAHs including Benz(a)anthracene (BaA), Chrysene (CHR), Benzo(b)fluoranthene (BbF) and Benzo(a)pyrene (BaP) were investigated by GC-MS in total 468 tea products, which were contaminated up to $4.63ng\;g^{-1}$. Mate tea was the most highly contaminated by BaA, CHR, BbF and BaP and followed by Solomon's seal and Chrysanthemum. The Margin of Exposures calculated by the concentration of BaA, CHR, BbF and BaP and consumption amount of tea were higher than 10,000, and the risk of PAHs in tea were low concern to public health.

• Korean Journal of Pharmacognosy
• /
• v.53 no.3
• /
• pp.170-180
• /
• 2022

Polycyclic aromatic hydrocarbons(PAHs) contents were analyzed by measuring benz(a)anthracene(BaA), chrysene(Chr), benzo(b)fluoranthene(BbF) and benzo(a)pyrene(BaP), and the related risk characterization was conducted for 113 samples out of 14 different agricultural products used for food and medicine. Detection rate of PAHs was 90.3% as a whole, and the highest one was 80.5% for BaP. The detection rate of BaP exceeding the maximum permitted concentration of Rehmanniae Radix Preparata and Rehmanniae Radix, 5.0 ㎍/kg was 1.8%, and the detection rates of BaA, Chr and BbF were within the range of 2.7~10.6%. The highest average concentration of BaA was 3.41 ㎍/kg detected from Lycii Fructus, while those of Chr, BbF, BaP and PAH4(sum of detected BaA, Chr, BbF and BaP) were 5.00, 1.79, 2.36, 12.36 ㎍/kg, respectively, detected from Rehmanniae Radix Preparata. As for the risk characterization on PAHs, the overall MOE(Margin of Exposure) values were measured within the range of 10⁵~10⁷, which is unlikely to cause direct health concerns, but the worring values of MOE were measured 6.57×10⁴ for BaP and 6.10×10⁴ for PAH4 from Rehmanniae Radix Preparata, which may require an improvement plan to reduce BaP contents.

• Analytical Science and Technology
• /
• v.24 no.4
• /
• pp.266-274
• /
• 2011

Using a Hitachi LaChrom Ultra 2000U, a reverse phase ultra high performance liquid chromatography (u-HPLC) method was developed for the rapid quantification of 14 PAHs in foods. The proposed method for PAH analysis is based on solid phase extraction (SPE) cartridges; the determination was carried out by u-HPLC with fluorimetric detection. The method was very sensitive; PAH concentration levels were in a low ${\mu}g$/kg range and could be detected and quantified. Six samples of food were analyzed. Among PAHs, PHE was found in most of samples, the concentration ranging from 2.5 to 19.9 ${\mu}g$/kg. The contents of benzo[c]fluorine (BCL), pyrene (PYR), benzo[a]anthracene (BaA), chrysene (CHR), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF) were low at the '${\mu}g$/kg' level or were less than LOD.

• Asian-Australasian Journal of Animal Sciences
• /
• v.26 no.12
• /
• pp.1689-1697
• /
• 2013

This study was designed to determine the effect of physical form and urea treatment of rice straw on rumen fermentation, microbial protein synthesis and nutrient digestibility. Four rumen-fistulated dairy steers were randomly assigned according to a 2 (2 factorial arrangement in a 4 (4 Latin square design to receive four dietary treatments. Factor A was roughage source: untreated rice straw (RS) and urea-treated (3%) rice straw (UTRS), and factor B was type of physical form of rice straw: long form rice straw (LFR) and chopped (4 cm) rice straw (CHR). The steers were offered the concentrate at 0.5% body weight (BW) /d and rice straw was fed ad libitum. DM intake and nutrient digestibility were increased (p<0.05) by urea treatment. Ruminal pH were decreased (p<0.05) in UTRS fed group, while ruminal ammonia nitrogen ($NH_3$-N) and blood urea nitrogen (BUN) were increased (p<0.01) by urea treatment. Total volatile fatty acid (VFA) concentrations increased (p<0.01) when steers were fed UTRS. Furthermore, VFA concentrations were not altered by treatments (p>0.05), except propionic acid (C3) was increased (p<0.05) in UTRS fed group. Nitrogen (N) balance was affected by urea treatment (p<0.05). Microbial protein synthesis (MCP) synthesis were greater by UTRS and CHR group (p<0.05). The efficiency of microbial N synthesis was greater for UTRS than for RS (p<0.05). From these results, it can be concluded that using the long form combined with urea treatment of rice straw improved feed intake, digestibility, rumen fermentation and efficiency of microbial N synthesis in crossbred dairy steers.

• Journal of Environmental Science International
• /
• v.19 no.7
• /
• pp.861-869
• /
• 2010

The present study aims to evaluate the characteristics of atmospheric polycyclic aromatic hydrocarbons (PAHs) pollution in roadside and residential areas of two Korean metropolitan cities (Seoul and Incheon) and a background area (Seokmolee). This purpose was established by analyzing temporal and spacial concentration distribution of total and 7 individual PAHs, which were extracted from ambient particulate matters, and by utilizing a multivariate statistical method (principal component analysis, PCA) for the qualitative determination of potential PAH sources. Target PAHs included benzo(a)anthracene (BaA), benzo(a)pyrene (BaP), benzo(b)fluoranthene (BbF), benzo(k)fluoranthene (BkF), chrysene (Chr), dibenzo(a,h)anthracene (DahA), and indeno(1,2,3-cd)pyrene (IcdP). For all surveyed sites, the concentrations of total PAHs were higher in winter season than in other seasons. However, the concentrations of individual PAHs varied with surveyed sites. In both residential and roadside sites of Seoul and Incheon, BbF revealed the highest atmospheric levels. For all 7 target PAHs, the ambient concentrations were higher in Seoul and Incheon than in a background area (Seokmolee). In both residential and roadside areas, the concentrations of 4 target PAHs (BaA, BbF, BkF, DahA) were higher in Incheon than in Seoul. However, both the residential and roadside Chr concentrations were comparable in Seoul and Incheon. In addition, the residential IcdP concentrations were higher in Incheon than in Seoul, whereas the roadside concentrations were higher in Seoul. The roadside and residential BaP concentrations exhibited the reverse result to the IcdP concentrations. An PCA analysis suggested that atmospheric PAHs in both residential and roadside areas would be due to combined effects of several potential sources such as gasoline- and diesel-fueled vehicles, coal/oil combustion, and waste incineration.

• Archives of Pharmacal Research
• /
• v.18 no.6
• /
• pp.449-453
• /
• 1995

The search for patinum (II)-based compounds with improved therapeutic properties was prompted to design and synthesize a new family of water-soluble, third generation cis-diamminedichlorplatinum (II) complexes linked to uracil and uridine. Six heretofore undescribed uracil and uridine-platinum (II) complexes are ; [N-(2-aminoethyl)uracil-5-carboxamide]dichloroplatinum (II)(3a), [N-2(2-aminoethyl)uracil-6-carboxmide]dichloroplatinum (II) (3b),[5-(2-aminorthyl)carbamoyl-2',3',5',-tri-O-acetyluridine] dichloroplatinum (II) (6b), [5-(2-aminoethyl)-carbamoyl]-2',3',5',-tri-O-acetyluridine] dichloroplatinum (II) (6b), [5-(2-aminoethyl)carbamoylu-ridine]dihloroplatinum (II) (7a), [6-(2-aminoethyl)carbamoyluridine]dichloroplatinum (II) (7b). These analogues were prepared from the key starting materials, 5-carboxyuracil (1a) and 6-carboxyuracil (1b) which were reacted with ethylenediamine to afford the respective N-(2-aminoethyl)uracil-5-carboxmide (2a) land N-(2-aminoethyl)uracil-6-carboxamide (2b). The cisplatin complexes 3a and 3b were obtained through the reaction of the respective 2a and 2b ficiently introduced on the .betha.-D-ribose ring via a Vorbruggen-type nucleoside coupling procedure with hexamethyldisilazane, trimethylchlorosilane and stannicchloride under anhydrous acetonitfile to yield the sterospecific .betha.-anomeric 5-carboxy-2',3',5'-tri-O-acetyluridine (4a) and 6-carboxy-2',3',5'-tri-O-acetyluridine (4b), respective 5-(2-aminoethyl)carbamoyl-2',3',5'-tri-O-acetyluridine (5a) and 6-(2-aminoethyl)carbamoyl-2',3',5'-tri-O-acetyluridine (5b). The diamino-uridines 5a and 5b were reacted with potassium tetrachloroplatinate (II) to give the novel nucleoside complexes, 6a and 6b respectively which were deacetylated into the free nucleosides, 7a and 7b by the treatment with CH/sub 3/ONa. The antitumor activities were evaluated against three cell lines (K-562, FM-3A and P-388).

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.9
• /
• pp.1444-1452
• /
• 2007

An in vitro experiment was conducted to evaluate the differences in microbial activity of five faecal inocula from weaned pigs and one faecal inoculum from unweaned pigs in combination with 6 substrates. The substrates tested were negative control diet, corn, soybean meal, oligofructose (OF), ground chicory roots and a mixture (60% chicory pulp and 40% OF). The inocula used were derived from pigs fed either a corn-soy based diet without antibiotics (NCON), the NCON diet supplemented with oligofructose (OF), a mixture of chicory pulp (40%) and OF (60%) (MIX), ground chicory roots (CHR) or the NCON diet supplemented with antibiotics (PCON). The cumulative gas production measured fermentation kinetics and end products, such as total gas production, ammonia and volatile fatty acids, were also determined. Both the substrate and the inoculum significantly affected the fermentation characteristics. The cumulative gas production curve showed that different substrates caused more differences in traits of fermentation kinetics than the different inocula. Inocula of weaned pigs gave a significantly higher VFA production compared to the inoculum from unweaned animals, whilst the rate of fermentation and the total gas produced did not differ. OF showed the highest fermentation kinetics and the lowest $NH_3$, pH and OM loss compared to other substrates. It was concluded that the microbial activity was significantly affected by substrate and inoculum. Inoculum from weaned pigs had more potential for microbial fermentation of the carbohydrate ingredients and oligofructose than that of unweaned pigs. A combination of high and low polymer inulin may be more beneficial to the gut ecosystem than using high- or low-polymer inulin alone.

• Lingua Humanitatis
• /
• v.6
• /
• pp.381-405
• /
• 2004

Elegie und Iambos gehoren zu den altesten Genre der griechischen Lyrik. Erst in diesen Gedichten aus den 7. Jh. v. Chr. beginnt der Dichter als pers nliches Subjekt seine eigenen Erfahrungen auszusprechen, w hrend or im Epos objektiv und leidenschaftslos hinter seinem Stoff zur ckblieb. So behauptet man, dass in den Gedichten der beiden Genre 'das Erwachen der Personlichkeit' (B. Snell) erfolge. Doch dieser pers nliche Charakter der fruhgriechischen Dichtung darf nicht im Sinne der Subjektivit t verstanden werden, wie man sie in der modernen Lyrik findet. Dem subjektiven Gef hl, das in den uns tradierten Fragmenten aus der fr hgriechischen Dichtung zum Ausdruck kommt, kann man n mlich ein gemeinsames Pathos ablesen, das die Elegiker und Iambographen in der Zeit des politischen Umwandels angesichts der conditio humana empfunden batten, das Pathos n mlich, das sich wohl unter dem Begriff amechanie am besten zusammenfassen lasst. In solchen Grenzsituationen, wie Krieg, Ungluck, Altern, sprechen sich die Dichter vollig hilflos aus und beklagen sich uber die menschliche Unwissenheit uber das erh ngte Schicksal. Bezeichnend f r ihre Begegnung mil der Hilflosigkeit des menschlichen Daseins ist jedoch der Realit tssinn, den sie aus ihren Erfahrungen der conditio humara bzw. amechanie gewonnen haben: Sie wollen sich weder durch einen heroischen Gedanken uber den Nachruhm noch durch einen religiosen Glauben an das Jenseits tauschen lassen. Sie wollen vielmehr hic et nunc einen Weg finden, sich mit der amechanie abzufinden. Und dabei werden zwei verschiedene Lebenswege eingeschlagen, der Weg des erotischen Hedonismus (Mimnermos und Semonides) und der des 'sardonischen' Realismus (Archilochos). Damit weisen uns die fruhgriechische Lyrik auf zwei typische Lebensrichtungen hin, die sich spater in der griechischen Ethik einb rgern sollen.