Levels of Heavy Metals in Canned Bonito,Sardines, and Mackerel Produced in Turkey

Concentrations of selected metals were determined using ICP-MS in canned bonito, sardines and mackerel commercialized in Turkey. Thirty samples and two different brands were sampled for each fish species. The minimum and maximum concentrations of trace metals in canned bonito, sardines and mackerel were found as 0.000–34.742, 0.000–89.015, 0.000–28.725 mg/kg for iron, 2.388–26.620, 10.930–41.340, 4.778–29.270 mg/kg for zinc, 0.331–1.548, 0.599–2.242, 0.336–2.884 mg/kg for copper, 0.000–0.065, 0.000–0.113, 0.000–0.115 mg/kg for cadmium, 0.000–0.190, 0.000–0.158, 0.000–0.385 mg/kg for tin, 0.000–0.111, 0.000–0.223, 0.000–0.208 mg/kg for mercury and 0.000–3.046, 0.000–2.875, 0.000–3.529 mg/kg for lead, respectively. These levels are similar those found in other studies. Although the samples have concentrations within permissible limits for Zn, Cu, Sn and Hg, some of them contained Fe, Cd and Pb above these limits. Periodical controls of metals in canned fish are essential both to protect human health and to provide data on this subject.     

Determination of Trace Elements in Three Mushroom Samples of Basidiomycetes from Shandong,China

We have determined the trace element composition of three mushrooms of Basidiomycetes, used in traditional Chinese medicine using atomic absorption spectrophotometer (AAS). Metal concentrations in mushrooms were 203–401 mg/kg for iron, 22–51 mg/kg for manganese, 84–116 mg/kg for zinc, 24.1–41.3 mg/kg for copper, 1.6–5.6 mg/kg for lead, 3.3–4.4 mg/kg for chromium, 9.3–11.5 mg/kg for nickel, 0 mg/kg for vanadium, and 55.3–71 mg/kg for magnesium. The trace metal concentrations in mushrooms are hardly affected by the ecosystem and soil where they grew, as well as by the mushroom species and trace metal species. The results can be used to set new standards to control the quality of the three mushrooms of Basidiomycetes—Ganoderma lucidum, Coprinus comatus, and Grifola frondosa.     

Roles of complex gangliosides in the development of experimental autoimmune encephalomyelitis

We induced experimental autoimmune encephalomyelitis (EAE) inGM2/GD2 synthase knockout mice (GM2/GD2^–/–), whichcannot synthesize complex gangliosides, such as GM1, GD1a, GD1b,GT1b, and GQ1b, to investigate the roles of complex gangliosidesin the pathogenesis of this disease. We used myelin-oligodendrocyteglycoprotein (MOG) as an immunogen. In active immunization EAE,the severity of clinical score was not different but the diseaseonset was significantly delayed in GM2/GD2^–/– comparedwith those in wild-type mice. When we transferred MOG-reactiveT cells from GM2/GD2^–/– or wild-type mice to wild-typemice, no significant differences were observed between the twogroups. In contrast, when we transferred MOG-reactive T cellsfrom wild-type mice to GM2/GD2^–/– or to wild-typemice, the onset of EAE in GM2/GD2^–/– mice was delayed.The recall response of MOG-specific T cells, the function ofantigen presenting cells, or the expression of several adhesionmolecules in the endothelium were not significantly differentbetween GM2/GD2^–/– and wild-type mice. On the otherhand, quantitative analysis of cellular infiltration in thecentral nervous system (CNS) on day 9 of active immunizationEAE showed that the CD4⁺ cell number in the CNS isolated fromGM2/GD2^–/– mice was significantly less than thatfrom wild-type mice. It indicated that the delayed onset ofEAE in GM2/GD2^–/– mice was due to the delay of themigration of pathogenic T cells into the CNS. Thus, the complexgangliosides may be involved in the T cell–endothelialcell interaction in the pathogenetic process of EAE.     

Hydrobiological analysis of a peat bog with emphasis on its planktonic diversity and population dynamics in Bumdeling Wildlife Sanctuary, eastern Bhutan

A pioneering limnological investigation was carried out in Bhutan in a small peat bog in the Trashiyangtse district (1950 m above sea level) from February 2000 to January 2002. The sampled pond water had low transparency (55.0–95.0 cm), was typically acidic (pH 5.69–6.58) with soft water (alkalinity, 11.0–36.0 mg/l; total hardness, 10.0–34.0 mg/l), and had low to moderate specific conductivity (17.0–62.0 μS/cm). Further, moderate Na (2.0–6.8 mg/l), K (1.8–13.5 mg/l), sulphate (0.85–2.99 mg/l), and silicate (2.5–15.0 mg/l) concentrations as well as low nutrient levels such as phosphate (0.006–0.170 mg/l) and nitrate (0.003–0.180 mg/l) characterize the water in the peat bog. The recorded net plankton comprised 27 species of phytoplankton and 49 species of zooplankton, with the latter indicating greater homogeneity and breaking down into Rotifera (23 species) > Cladocera (13 species) > Rhizopoda (8 species) > Copepoda (3 species) > Ostracoda = Nematoda (1 species each). On the other hand, the net plankton density ranged between 93 and 692 number/l (n/l) with numerical dominance by phytoplankton (68.5% ± 12%), of which Chlorophyceae were predominant (90 ± 63 n/l). Zooplankton showed moderately high diversity (2.745 ± 0.293) and evenness (0.925 ± 0.049) and exhibited almost equal abundance of four recorded groups, namely Cladocera (20 ± 15 n/l) > Rotifera (15 ± 6 n/l) > Copepoda (14 ± 7 n/l) > Rhizopoda (14 ± 4 n/l). While no significant impact of abiotic factors was recorded on zooplankton density, rainfall alone was the most important factor that influenced net plankton and various groups of phytoplankton. Comments on some comparative limnological attributes are also made with similar as well as different habitats in the nearby Himalayan countries.     

Spatial distribution of extractable organohalogens in northern pink shrimp in the North Atlantic

Extractable organohalogens (EOX) are organic compounds that contain chlorine, bromine and/or iodine, which can be separated from the matrix by liquid/liquid or liquid/solid extraction. A combination of instrumental neutron activation analysis (INAA) and solvent extraction methods has been developed for the determination of EOX from the shrimpPandalus borealis. Levels of EOX were evaluated for spatial trends for shrimp caught in several areas off the Labrador coast, off the coast of Nova Scotia, and off the coast of Maine. Muscle contained 1.09–6.05 Μg EOCl/g tissue and 105–498 Μg extractable organochlorine (EOCl)/g lipid; 0.0607–0.288 Μg extractable organobromine (EOB)r/g tissue and 4.74-10.5 Μg EOBr/g lipid; and 0.014–0.048 Μg extractable organoiodine (EOI)/g tissue and 1.03–1.76 Μg EOI/g lipid, respectively. The levels of EOC1 in roe were 1.60–12.34 Μg/g tissue and 39.0-146 Μg/g lipid. In roe, the EOBr levels were 0.707–1.03 Μg/g tissue and 6.96–13.5 Μg/g lipid; and EOI levels were 0.123–0.349 Μg/g tissue and 1.42–4.11 Μg/g lipid. The EOCl, EOBr, and EOI levels in roe increased noticeably from north to south along the coast of Labrador. Samples taken from the coast of Maine and from Canso Hole were typically higher in EOCl levels than those taken from Labrador. The results for EOBr and EOI were in the same range as those from Labrador.     

Characterization and Distribution of the Selected Metals in the Scalp Hair of Cancer Patients in Comparison with Normal Donors

Eighteen metals were estimated in the scalp hair samples from cancer patients (n = 111) and normal donors (n = 113). Nitric acid–perchloric acid wet digestion procedure was used for the quantification of the selected metals by flame atomic absorption spectrophotometry. In the scalp hair of cancer patients, highest average levels were found for Ca (861 μg/g), followed by Na (672 μg/g), Zn (411 μg/g), Mg (348 μg/g), Fe (154 μg/g), Sr (129 μg/g), and K (116 μg/g), whereas in comparison, the dominant metals in the scalp hair of normal donors were Ca (568 μg/g), Zn (177 μg/g), Mg (154 μg/g), Fe (110 μg/g), and Na (103 μg/g). The concentrations of Ca, Cd, Co, Cr, Fe, K, Mg, Mn, Na, Ni, Pb, Sb, Sr, and Zn were notably higher in the hair of cancer patients as compared with normal donors, which may lead to a number of physiological disorders. Strong positive correlations were found in Mn–Pb (0.83), Cd–Cr (0.82), Cd–Li (0.57), Fe–Pb (0.56), and Fe–Mn (0.55) in the hair of cancer patients whereas Na–Cd, Li–Cr, Li–Co, Co–Cd, Li–Cd, Na–Co, Na–Li, Ca–Mg and Na–Cr exhibited strong relationships (r > 0.50) in the hair of normal donors. Principal Component Analysis (PCA) of the data revealed seven PCs, both for cancer patients and normal donors, but with significantly different loadings. Cluster Analysis (CA) was also used to support the PCA results. The study evidenced significantly different pattern of metal distribution in the hair of cancer patients in comparison with normal donors. The role of trace metals in carcinogenesis was also discussed.     

Immunogenicity of synthetic fragments corresponding to variable and conservative sites of H3N2 influenza virus hemagglutinin heavy chain

Immunogenic properties of synthetic peptides corresponding to regions 122–133, 136–147, 154–164, and 314–328 of the heavy chain (HA1) of A/Aichi/2/68 virus hemagglutinin were studied. Peptides 122–133 and 136–147 together form a nearly complete antigenic determinant A, peptide 154–164 is a part of determinant B, and peptide 314–328 corresponds to the C-terminal HA1 fragment. In a model influenza A/Aichi/2/68 infection in CBA mice, a protective effect of conjugates of BSA with peptides 136–147 and 314–328 was shown. Immunization of animals with conjugates BSA-(136–147) and BSA-(314–328) in combination with interferon inducers (larifan and ridostin) and a plant immunomodulator (immunomax) intensified the protection of mice against the influenza infection.     

Induction of human cytotoxic T lymphocytes that preferentially recognise tumour cells bearing a conformational p53 mutant

 The tumour-suppressor gene p53 is pivotal in the regulation of apoptosis, and point mutations within p53 are the commonest genetic alterations in human cancers. Cytotoxic T lymphocytes (CTL) recognise peptide-MHC complexes on the surface of tumour cells and bring about lysis. Therefore, p53-derived peptides are potential candidates for immunisation strategies designed to induce antitumour CTL in patients. Conformational changes in the p53 protein, generated as a result of point mutations, frequently expose the 240 epitope, RHSVV (amino acids 212–217), which may be processed differently from the wild-type protein resulting in an altered MHC-associated peptide repertoire recognised by tumour-specific CTL. In this study 42 peptides (37 overlapping nonameric peptides, from amino acids 193–237 and peptides 186–194, 187–197, 188–197, 263–272, 264–272, possessing binding motifs for HLA-A2) derived from the wild-type p53 protein sequence were assayed for their ability to stabilise HLA-A2 molecules in MHC class I stabilisation assays. Of the peptides tested, 24 stabilised HLA-A2 molecules with high affinity (fluorescence ratio>1.5) at 26 °C, and five (187–197, 193–200, 217–224, 263–272 and 264–272) also stabilised the complexes at 37 °C. Peptides 188–197, 196–203 and 217–225 have not previously been identified as binders of HLA-A2 molecules and, of these, peptide 217–225 stabilised HLA-A2 molecules with the highest fluorescence ratio. Peptide 217–225 was chosen to generate HLA-A2-restricted CTL in vitro; peptide 264–272 was used as a positive control. The two primary CTL thus generated (CTL-217 using peptide 217–225; and CTL-264 using peptide 264–272) were capable of specifically killing peptide-pulsed T2 or JY cells. In order to determine whether these peptides were endogenously processed and to test the hypothesis that mutants expressing different protein conformations would generate an alternative peptide repertoire at the cell surface, a panel of target cells was generated. HLA-A2⁺ SaOs-2 cells were transfected with p53 cDNA containing point mutations at either position 175 (R → H) or 273 (R → H) (SaOs-2/175 and SaOs-2/273). Two HLA-A2-negative cell lines, A431 and SKBr3, naturally expressing p53 mutations at positions 273 and 175 respectively, were transfected with a cDNA encoding HLA-A2. The results showed that primary CTL generated in response to both peptides were capable of killing SaOs-2/175 and SKBr3-A2 cells, which possess the same mutation, but not SaOs-2/273, A431-A2 or SKBr3 cells transfected with control vector. This suggests that these peptides are presented on the surface of SaOs-2/175 and SKBr3-A2 cells in a conformation-dependent manner and represent potentially useful target peptides for immunotherapy. Received: 23 March 2000 / Accepted: 22 June 2000     

The onset of oscillatory dynamics in models of multiple disease strains

 We examine a generalised SIR model for the infection dynamics of four competing disease strains. This model contains four previously-studied models as special cases. The different strains interact indirectly by the mechanism of cross-immunity; individuals in the host population may become immune to infection by a particular strain even if they have only been infected with different but closely related strains. Several different models of cross-immunity are compared in the limit where the death rate is much smaller than the rate of recovery from infection. In this limit an asymptotic analysis of the dynamics of the models is possible, and we are able to compute the location and nature of the Takens–Bogdanov bifurcation associated with the presence of oscillatory dynamics observed by previous authors. Received: 5 December 2001 / Revised version: 5 May 2002 / Published online: 17 October 2002 Keywords or phrases: Infection – Pathogen – Epidemiology – Multiple strains – Cross-immunity – Oscillations – Dynamics – Bifurcations     

Association of the −33C/G <Emphasis Type="Italic">OSF</Emphasis>-<Emphasis Type="Italic">2</Emphasis> and the 140A/G <Emphasis Type="Italic">LF</Emphasis> gene polymorphisms with the risk of chronic rhinosinusitis with nasal polyps in a Polish population

Nasal polyps are strongly associated with a risk of chronic rhinosinusitis development as well as other obstruction including asthma and allergy. The following study tested the association of the 140A/G polymorphism of lactoferine (LF) encoding gene and the −33C/G polymorphism of osteoblast-specific factor-2 (OSF-2) encoding gene with a risk of chronic rhinosinusitis with nasal polyps in a Polish population. One hundred ninety five patients of chronic rhinosinusitis with nasal polyps as well as 200 sex, age and ethnicity matched control subjects without chronic sinusitis and nasal polyps were enrolled in this study. Among the group of patients 63 subjects were diagnosed with allergy and 65 subjects with asthma, respectively. DNA was isolated from peripheral blood lymphocytes of patients as well as controls and gene polymorphisms were analyzed by restriction fragments length polymorphism polymerase chain reaction (RFLP-PCR). We reported that the 140A/G LF (OR 4.78; 95% CI 3.07–7.24), the −33C/G OSF-2 OR 3.48; 95% CI 2.19–5.52) and the −33G/G OSF-2 (OR 16.45; 95% CI 6.71–40.30) genotypes were associated with an increased risk of chronic rhinosinusitis with nasal polyps among analyzed group of patients. Moreover, the group of patients without allergy or asthma indicated the association of the −33C/G (OR 3.72; 95% CI 2.24–6.19 and OR 15.11; 95% CI 5.91–38.6) and −33G/G (OR 3.73; 95% CI 2.24–6.19 and OR 14.07; 95% CI 5.47–36.16) genotypes of the OSF-2 as wells as 140A/G (OR 3.89; 95% CI 2.40–6.31 and OR 3.62; 95% CI 2.45–5.34) genotype of OSF-2 with an increased risk of chronic rhinosinusitis with nasal polyps. Finally, it was also found that the selected group of patients with allergy or asthma indicated a very strong association of the −33C/G (OR 2.40; 95% CI 1.23–4.69 and OR 2.40; 95% CI 1.23–4.69, respectively) and −33G/G (OR 16.01; 95% CI 5.77–44.41 and OR 17.90; 95% CI 6.53–49.05, respectively) genotypes of the OSF-2 as wells as 140A/G (OR 3.22; 95% CI 1.74–6.11 and OR 3.25; 95% CI 1.75–6.04, respectively) genotypes with an increased risk of chronic rhinosinusitis with nasal polyps. Thus, our results suggest that LF and OSF-2 gene polymorphisms may have deep impact on the risk of rhinosinusitis nasal polyps’ formation which may also depend on asthma or allergy. Our results showed that the 140A/G polymorphism of LF gene and the −33C/G polymorphism of the OSF-2 gene may be associated with the risk of chronic rhinosinusitis with nasal polyps in a Polish population.     

Distribution of dissolved organic carbon and dissolved fulvic acid in mesotrophic Lake Biwa, Japan

The dissolved organic carbon (DOC) concentrations in mesotrophic Lake Biwa were determined by a total organic carbon (TOC) analyzer, and DOC molecular size distributions were determined by size exclusion chromatography (SEC) using a fluorescence detector at excitation/emission (Ex/Em) levels of 300/425 nm with the eluent at pH 9.7. The fluorescence wavelengths for detection were chosen from the result of excitation–emission matrix spectrometry (EEM) analysis for dissolved fulvic acid (DFA) extracted from Ado River (peak A, Ex/Em = 260–270/430–440 nm; peak B, Ex/Em = 300–310/420–430 nm). Ado River DFA was eluted with a retention time (RT) of 7.4–8.9 min and the apparent molecular weight was estimated at 22–87 kDa based on the elution curve for the spherical protein molecular weight standard. A DFA peak eluted at the same retention time as Ado River DFA also appeared in all the samples of Lake Biwa water. From the linear relationship between the peak areas with an RT of 7.4–8.9 min by SEC analysis and DOC values of DFA by TOC analysis of a series of DFA samples (r² = 0.9995), the concentrations of DFA in the lake water were roughly calculated. DFA was distributed within the range 0.25–0.43 mg C l⁻¹ and accounted for 15%–41% of DOC, with the highest ratios observed at a depth of 70 m in August and the lowest at 2.5 m in May.     

A mapping and evolutionary study of porcine sex chromosome gene

A combination of FISH and RH mapping was used to study the evolution of sex chromosome genes in the pig. In total, 19 genes were identified, including 3 PAR genes (STS, KAL, PRK). The gene order of the porcine X Chromosome (Chr) closely resembled the human X Chr (PRK/STS/KAL–AMELX–EIF2s3X/ZFX–USP9X–DBX–SMCX), suggesting that the porcine X has undergone very little rearrangement during evolution. For the porcine Y Chr, two linkage groups of 10 NRY genes were found, and the following order was established: Ypter–(AMELY–EIF2S3Y/ZFY–USP9Y–DBY/UTY)–(TSPY–SMCY–UBE1Y–SRY)–CEN. This gene order showed greater conservation with the murine Y than with the human Y Chr. In addition, all porcine Y Chr genes mapped to Yp, which is similar to the mouse and included EIF2s3Y and UBE1Y, which are not present in humans. Interestingly, complete conservation of X/Y homologous gene order was found between the pig X and Y Chrs, indicating that the porcine Y Chr has not undergone extensive reorganisation with respect to the X. This suggests that the order of the X/Y homologous genes of the porcine X and Y Chrs may closely resemble the ancestral gene order of the eutherian sex chromosomes.     

Validity of the gerreid fish,Gerres macracanthus Bleeker, 1854, with designation of a lectotype,and designation of a neotype forG. filamentosus Cuvier, 1829

Gerres macracanthus Bleeker, 1854, for many years having been explicitly or tentatively synonymized withG. filamentosus Cuvier, 1829, is redescribed as a valid species.Gerres macracanthus differs fromG. filamentosus in lacking vertical rows of dark ovoid spots on the body, having instead only indistinct vertical bands in both subadult and adult stages, in addition to shorter second and third anal fin spines (9.1–13.9% and 10.4–14.4% of standard length [SL] vs. 12.3–19.6% and 11.9–17.3% of SL), fewer ored lateral line scales (41–44 vs. 43–46) and fewer scales between the base of the 5th dorsal fin spine and the lateral line (4–5 vs. 4 1/2–5 1/2), and above and below the lateral line (5 1/2–6 1/2/9 1/2–10 1/2 vs. 6 1/2–7 1/2/10 1/2–11 1/2). AlthoughG. filamentosus has similarly, indistinct vertical bands on the body up to ca. 100 mm SL, specimens over ca. 100 mm SL develop diffuse ovoid spots in each vertical band. Furthermore,G. macracanthus is generally a smaller species, apparently attaining a maximum size of ca. 170 mm SL, compared with ca. 250 mm SL forG. filamentosus. Formerly known from the Philippines, Indonesia, New guinea, India and the Arabian Gulf,G. macracanthus is newly-recorded from Japan, China, the Gulf of Thailand, the Red Sea and South Africa. A lectotype and three paralectotypes are designated forG. macracanthus Bleeker, 1854, in addition to a neotype forG. filamentosus Cuvier, 1829.     

Identification and characterization of fermentation inhibitors formed during hydrothermal treatment and following SSF of wheat straw

A pilot plant for hydrothermal treatment of wheat straw was compared in reactor systems of two steps (first, 80°C; second, 190–205°C) and of three steps (first, 80°C; second, 170–180°C; third, 195°C). Fermentation (SSF) with Sacharomyces cerevisiae of the pretreated fibers and hydrolysate from the two-step system gave higher ethanol yield (64–75%) than that obtained from the three-step system (61–65%), due to higher enzymatic cellulose convertibility. At the optimal conditions (two steps, 195°C for 6 min), 69% of available C6-sugar could be fermented into ethanol with a high hemicellulose recovery (65%). The concentration of furfural obtained during the pretreatment process increased versus temperature from 50 mg/l at 190°C to 1,200 mg/l at 205°C as a result of xylose degradation. S. cerevisiae detoxified the hydrolysates by degradation of several toxic compounds such as 90–99% furfural and 80–100% phenolic aldehydes, which extended the lag phase to 5 h. Acetic acid concentration increased by 0.2–1 g/l during enzymatic hydrolysis and 0–3.4 g/l during fermentation due to hydrolysis of acetyl groups and minor xylose degradation. Formic acid concentration increased by 0.5–1.5 g/l probably due to degradation of furfural. Phenolic aldehydes were oxidized to the corresponding acids during fermentation reducing the inhibition level.     

Possible dynamic anchor points in a benzoxazinone derivative–human oxytocin receptor system — a molecular docking and dynamics calculation

In this study, we performed a molecular docking and dynamics simulation for a benzoxazinone–human oxytocin receptor system to determine the possible hydrophobic and electrostatic interaction points in the dynamic complex. After the homology modeling, the ligand was docked into the putative active using AutoDock 3.05. After the application of energetic and structural filters, the complexes obtained were further refined with a simulated annealing protocol (AMBER8) to remove steric clashes. Three complexes were selected for subjection to the molecular dynamics simulation (5 ns), and the results on the occurrence of average anchor points showed a stable complex between the benzoxazinone derivative and the receptor. The complex could be used as a good starting point for further analysis with site-directed mutagenesis, or further computational research. Figure The location of the ligands (complex B – blue; complex E – red; and complex F – green) in the transmembrane regions (TM1 – red; TM2 – blue; TM3 – yellow; TM4 – purple; TM5 – orange; TM6 – cyan; TM7 – pink) of the hOTR. For clarity, the EC and IC loops are not shown Electronic Supplementary Material Supplementary material is available at     

Drought adaptation of field grown wheat in relation to soil physical conditions

In order to investigate the effects of soil texture on possible non-hydraulic signals under field conditions, spring wheat plants (Triticum aestivum L. cv. Cadensa) grown in sand and loam soils and with a well developed root system were exposed to slow soil drying in the late vegetative stage of growth. Soil water potential and content were measured daily at different depths and plant responses were measured in flag leaves. When the average soil water potential in the top soil layers (0–25 cm depth in sand and 0–45 cm depth in loam) dropped to –60 or –70 kPa and the lower soil layers were still at field capacity, morning xylem [ABA] (0.03–0.04 vs. 0.06–0.08 mmol m-3) and midday leaf ABA concentration increased (250–300 vs. 400–450 ng/g DW) and leaf conductance decreased relatively to well-watered (control) plants (0.75–0.88 vs. 0.64–0.70 mol m-2 s-1). These responses took place before any decrease in leaf water potential occurred as compared with control plants, indicating that they were triggered by root-borne signals due to reduced root water status in the top soil layers. At this stage the soil water content was as low as 6% by volume, the fraction of roots in ‘wet’ soil was 0.12 and relative available soil water was 45% in sand and still high 20%, 0.48 and 70%, respectively, in loam of the whole soil profile indicating that roots were responding to soil water availability and not soil water content at a certain evaporative demand. In addition, similar responses occurred at high and low evaporative demands (3.4–5.2 vs. 0.6–4.0 mm/day of potential evapotranspiration). This revised version was published online in July 2006 with corrections to the Cover Date.     

Organization of biosynthetic gene cluster for avermectin in Streptomyces avermitilis: analysis of enzymatic domains in four polyketide synthases

The analysis of the incorporation of ¹³C-labeled precursors into avermectins indicates that the avermectin aglycons are synthesized by head-to-tail condensation of various acyl groups, which is similar to the biosynthesis of other polyketides. Polyketide synthases (PKS) use the appropriate CoA ester as a primer and add acetate units from malonyl-CoA and propionate units from methylmalonyl-CoA to assemble the polyketides. Avermectin aglycons are formed by addition to the starter unit (2-methylbutyrate or isobutyrate) of 12 acyl condensations in the order P–A–A–A–A–P–P–A–P–A–P–A (P, propionyl; A, acetyl). Within the 90-kb gene cluster for avermectin biosynthesis, the central 65-kb segment was found to be required for aglycon biosynthesis by phenotypic analysis of strains containing deletion or insertion mutations in this region. A complete sequence analysis of the 65-kb segment indicated that this segment encodes avermectin PKS. The avermectin PKS genes are organized into two converging blocks of ORFs. From the results of sequencing analysis, a feature of the two regions, aveA1/aveA2 and avea3/aveA4, is that they encode four kinds of large multifunctional polypeptides containing 55 domains which possess putative fatty acid synthase-like activities. The avermectin PKS (AVES 1–4) appear to contain two, three, or four modules. AVES 1 and 2 contain two and four modules, respectively, whereas AVES 3 and AVES 4 each contains three modules. The 12 modules correspond to the 12 cycles required for synthesis of the avermectin aglycon. Journal of Industrial Microbiology & Biotechnology (2001) 27, 170–176. Received 21 September 1999/ Accepted in revised form 14 September 2000     

In Vitro Activities of Fourteen Antimicrobial Agents Against Drug Susceptible and Resistant Clinical Isolates of Mycobacterium tuberculosis and Comparative Intracellular Activities Against the Virulent H37Rv Strain in Human Macrophages

Minimal inhibitory concentrations (MICs) of 14 first and second-line antituberculous drugs against drug-susceptible and drug-resistant clinical isolates of Mycobacterium tuberculosis (including the multiple drug-resistant or MDR-TB isolates), as well as the type strain H37Rv, were determined radiometrically by the Bactec 460-TB methodols. MICs (μg/ml) of all the fourteen drugs were within an extremely narrow range in case of susceptible strains; isoniazid (0.02–0.04), rifampin (0.2–0.4), ethambutol and streptomycin (0.5–2.0), ethionamide (0.25–0.5), D-cycloserine (25–75), capreomycin (1–2), kanamycin (2–4), amikacin (0.5–1.0), clofazimine (0.1–0.4), ofloxacin (0.5–1.0), ciprofloxacin (0.25–1.0), and sparfloxacin (0.1–0.4). The activity of second-line drugs remained unaltered against MDR-TB isolates resistant to routine first-line drugs. With peak serum level concentrations (Cmax), the intracellular killing of the virulent H37Rv strain was studied in detail in cultured human macrophages. Based on an decreasing order of bactericidal activity, our results showed the following spectrum of intracellular drug action: among the first-line drugs, rifampin > ethionamide = isoniazid > ethambutol > streptomycin > D-cycloserine; among second-line drugs, clofazimine = amikacin > kanamycin = capreomycin; among fluoroquinolones, sparfloxacin > ofloxacin > ciprofloxacin. On the other hand, contrary to atypical mycobacteria, the macrolide drug clarithromycin was inactive against both extracellular and intracellular M. tuberculosis. Received: 23 January 1996 / Accepted: 5 April 1996     

Fine mapping of T-cell determinants of bovine β-lactoglobin

T-cell recognition sites, i.e. T-cell determinants, of bovine β-lactoglobulin, a major allergen in milk, were analyzed in detail. For this purpose, we prepared primary cultures of lymph node cells from three strains of mice, C57BL/6 (H-2^b), C3H/HeN (H-2^k), and BALB/c (H-2^d), and examined the proliferative response of these cells to a complete set of overlapping 15-mer peptides which covered the entire sequence of β-lactoglobulin by shifting in single amino acid steps. We were able to determine the putative core sequence of each T-cell determinant and estimate its relative importance. In the case of C57BL/6 mice, dominant, subdominant, and minor determinants were identified as residues 122–130, 16–26, and 108–122, respectively, as represented by their core sequences. Each determinant peptide induced the production of interferon-γ, the amount of which showed a correlation with the intensity of the proliferative response induced by each determinant. In the case of C3H/HeN mice, a dominant determinant comprised of residues 140–148 was identified together with three subdominant and two minor determinants. Dominant T-cell determinants recognized in BALB/c mice were identified as residues 67–75, 71–79, and 80–88, and six other regions were identified as subdominant determinants. Comparisons between our results and the determinants predicted from relevant MHC-binding motifs reported to date revealed the inadequacy of the motifs in predicting even the dominant determinants. The information obtained by complete mapping of T-cell determinants as done in this study is expected to be helpful in establishment and evaluation of new prediction methods and also may contribute to the development of a new approach to control immune responses by manipulation of the T-cell determinants of allergens. This revised version was published online in June 2006 with corrections to the Cover Date.     

Channa nox, a new channid fish lacking a pelvic fin from Guangxi, China

 A new species of channid fish, genus Channa, is described from 7 specimens collected from the vicinity of Hepu, Guangxi Province, southern China. The new species, Channa nox, is distinguished from all other channid species by the following combination of characters: absence of pelvic fins, small rounded head (22.1%–26.8% SL), narrow interorbital width (19.6%–26.7% HL), short snout length (3.6%–5.1% SL), predorsal and prepectoral lengths (26.9%–28.4% SL and 24.8%–28.3% SL, respectively), 47–51 dorsal fin rays, 31–33 anal fin rays, 55–63 lateral line scales, 5.5–6.5 scales above lateral line, 9–13 cheek scales, 53–55 total vertebrae, 1 or 2 scale(s) on each side of lower jaw undersurface, the black upper half of body with 8–11 irregular (often anteriorly pointed V-shaped) bands or blotches, a large white-rimmed black ocellus on caudal peduncle and sparse white spots on the dark brown body and dorsal and caudal fins, as well as the shape of the hyomandibular process of the suprabranchial organs. Channa nox is sympatrically distributed with its morphologically most similar congener, C. asiatica. Received: January 18, 2001 / Revised: November 2, 2001 / Accepted: December 12, 2001