Sorption of Methyl tert -Butyl Ether (MTBE) and tert -Butyl Alcohol (TBA) to Hyporheic Zone Soils

Soil water distribution coefficients (K _d ) for methyl tert-butyl ether (MTBE) and its primary biodegradation intermediate tert-butyl alcohol (TBA) were determined for seven hyporheic zone soils ranging from 1 to 7% in organic carbon. Samples were collected in the area of the Spring Creek hyporheic zone in Ronan, Montana. Values for K _d ranged from 1.5 to 8.7 L kg^?1 for MTBE and from 0.15 to 0.41 L kg^?1 for TBA, and were highly correlated to the organic carbon content of the solids. However, for TBA the use of non-linear K _F values is more appropriate based on the results obtained, and the value of K _OC is calculated based on linear K _d transformation of the data. Distribution coefficients normalized to the fraction of organic carbon (log K _OC ) for MTBE and TBA were determined to be 2.13 ± 0.060 and 0.762 ± 0.088, respectively.     

Ellman's reagent: 5,5'-dithiobis(2-nitrobenzoic acid)--a reexamination.

Accurate determination of thiol groups by means of Ellman's reagent [5,5′-dithiobis(2-nitrobenzoic acid), DTNB] has been limited by uncertainty about the molar absorption coefficient of the dianion of the product, 2-nitro-5-thiobenzoic acid (TNB). A procedure is described for the purification of TNB by reduction of commercial DTNB followed by gel chromatography and crystallization. Pure DTNB is prepared by reoxidation of purified TNB followed by gel chromatography and crystallization. The molar absorption coefficient of the dianion of TNB is 14,150 at 412 nm in dilute aqueous salt solutions. This value was confirmed independently by reduction of purified DTNB with cysteine. Titration of sulphydryl groups with DTNB can be done at pH 7.27 where the thiol group of TNB is 99.8% in the intensely-colored conjugate base form while the hydroxide-promoted hydrolysis of DTNB is minimal.     

Di-tert.-butyl-dicarbonate, a useful tert.-Butyloxycardonylating reagent (author's transl)]

Di-tert.-butyl-dicarbonate is an ideal reagent for tert.-butyloxycarbonylating amino acids and their derivatives in regard to both reaction rate and simplicity of the procedure.     

A new and versatile reagent for incorporating multiple primary aliphatic amines into synthetic oligonucleotides.

A novel and versatile phosphoramidite, N-Fmoc-O1-DMT-O2-cyanoethoxydiisopropylamino-phosphinyl-3-am ino-1,2-propanediol (1, Fig. 1), has been synthesized and used to incorporate primary aliphatic amines into synthetic oligonucleotides. Its convenient preparation and use in solid phase oligonucleotide synthesis is described. Using phosphoramidite 1, an amino-modified oligonucleotide probe complementary to M13mp18 DNA was constructed with five primary amines attached to the 5'-terminus. The amino-modified oligonucleotide was subsequently labeled with biotin and employed in a dot-blot hybridization assay. As little as 0.5 ng of M13mp18 target DNA was colorimetrically detected.     

秦岭兰科一新记录属--虎舌兰属

虎舌兰属(Epipogium Gmelin ex Borkhausen)隶属于兰科(Orchidaceae)树兰族(Epidendreae),为一寡种属,分布于欧亚大陆、亚洲热带、非洲热带和大洋洲等地区。本属植物有3种,俱为腐生草本。     

Lymphoma associated antigen (LAA)--a unique biomarker for lymphomas.

A lymphoma associated antigen (LAA) isolated from pooled lymph nodes of confirmed Hodgkin's and non-Hodgkin's lymphomas has been purified and characterized. Using a xenogenic rabbit anti-serum, enzyme-linked immunosorbent assay (ELISA) and RIA were developed for LAA. LAA was detected in the sera of all confirmed lymphomas, the test being negative for normals, for patients with benign lymphadenitis and various other types of cancers. Except for a very few false positive results, no false negative was observed. LAA was identified in urine, CSF, saliva and gastric juice of a few lymphoma patients, and the test proved to be of diagnostic potential, as for a few patients it had a lead time of a few months over the histological diagnosis. In order to render the LAA test more precise and specific, monoclonal antibodies were generated by both in vitro and in vivo immunization procedures. Seven monoclonals were generated, viz. 7D6, 7D2, 7G2, 7C5, 6G2, 23B7 and 23G11, which exhibited cytoplasmic staining of frozen sections of malignant lymphoid tissues of B cell derived non-Hodgkin's lymphomas. Two of these monoclonal antibodies, 7D6 and 23B7, revealed strong cytoplasmic staining of frozen sections, impression smears and cytospin specimens of B cell non-Hodgkin's lymphomas. The reactivity was very weak or negative for T cell lymphomas. The test was negative for Hodgkin's disease and controls. These results were confirmed by dot blotting, immunoprecipitation and immunofluorescence study. By ELISA with a sensitivity of 15 ng/ml, serum LAA levels for lymphomas were in the range 72-1250 ng/ml. LAA could not be detected in the sera of normals and controls.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anti-arthritis effects of vitamin K(2) (menaquinone-4)--a new potential therapeutic strategy for rheumatoid arthritis

Vitamin K(2) (menaquinone-4, MK-4) has been reported to induce apoptosis in hepatocellular carcinoma, leukemia and myelodysplastic syndrome cell lines. The effects of MK-4 on the development of arthritis have never been addressed thus far. In the present study, we investigated the effect of MK-4 upon the proliferation of rheumatoid synovial cells and the development of arthritis in collagen-induced arthritis. We analyzed the effect of MK-4 on the proliferation of fibroblast-like synoviocytes using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The pro-apoptotic effect of MK-4 upon fibroblast-like synoviocytes was investigated with annexin V staining and DNA fragmentation and caspase 3/7 assays. Moreover, we analyzed the effect of MK-4 on the development of collagen-induced arthritis in female dark agouti rats. Our results indicated that MK-4 inhibited the proliferation of fibroblast-like synoviocytes and the development of collagen-induced arthritis in a dose-dependent manner. We conclude that MK-4 may represent a new agent for the treatment of rheumatoid arthritis in the setting of combination therapy with other disease-modifying antirheumatic drugs.     

High affinity acylating antagonists for muscarinic receptors.

The muscarinic antagonists pirenzepine and telenzepine were derivatized as alkylamino derivatives at a site on the molecules corresponding to a region of bulk tolerance in receptor binding. The distal primary amino groups were coupled to the cross-linking reagent meta-phenylene diisothiocyanate, resulting in two isothiocyanate derivatives that were found to inhibit muscarinic receptors irreversibly and in a dose-dependent fashion. Preincubation of rat forebrain membranes with an isothiocyanate derivative followed by radioligand binding using [3H]N-methylscopolamine diminished the Bmax value, but did not affect the Kd value. The receptor binding site was not restored upon repeated washing, indicating that irreversible inhibition had occurred. IC50 values for the irreversible inhibition at rat forebrain muscarinic receptors were 0.15 nM and 0.19 nM, for derivatives of pirenzepine and telenzepine, respectively. The isothiocyanate derivative of pirenzepine was non-selective as an irreversible muscarinic inhibitor, and the corresponding derivative prepared from telenzepine was 5-fold selective for forebrain (mainly m1) vs. heart (m2) muscarinic receptors.     

Sphinctocystis phyllodoces gen. n., sp. n. (Eugregarinida: Lecudinidae)--a new gregarine from Phyllodoce citrina (Polychaeta: Phyllodocidae)

A new species of aseptate gregarine, Sphinctocystis phyllodoces gen. n., sp. n., from the gut of a polychaete Phyllodoce citrina Malmgren, 1865 from White Sea is described. The electron and light microscopic data on trophozoits are presented. Taxonomy of the described species is discussed. Certain ultrastructural characters are included in generic and specific diagnoses. Order Eugregarinida Leger, 1900; suborder Aseptata Chakravarty, 1960; family Lecudinidae Kamm, 1922. GENUS: Sphinctocystis gen. n. TYPE SPECIES: Sphinctocystis phyllodoces sp. n. DIAGNOSIS: Characters of the family. Free trophozoits elongated, often with several annular constrictions. Anterior end asymmetric, without hooks, not separated from the body, with small apical papilla encircled by smooth area. Epicyte "classical", without additional axial formations at the tops of folds; epicytic folds high, monomorphic in cross sections, finger-shaped, with parallel sidewalls. In the gut of polychaetes. DIFFERENTIAL DIAGNOSIS: The new genus differs from Lecudina by having asymmetric anterior end, developed smooth area around the apical papilla, and monomorphic epicytic folds looking finger-shaped in cross sections. It also differs from Lankesteria by the absence of additional axial formations at the tops of the epicytic folds. It differs from both named genera by presence of annular constrictions on the trophozoit body. Sphinctocystis phyllodoces sp. n. DIAGNOSIS: Characters of the genus. Free trophozoits elongated, large, up to 617 x x 77 um. The average height of epicytic folds 976 nm, thickness 194 nm; there are 6-8 apical filaments and rippled dense structures per fold. Nucleus spherical (ellipsoid after fixation), 24-52 microm along longest axis, localised in anterior third of the body, carries several karyosomes of various size; 25-30 nm thick fibrils (possible fragments of nucleolonema) may be present in karyolymph. Other stages unknown. TYPE SERIES: Microscope preparation with 7 trophozoits, Karacci's haematoxylin stained, is kept in the Zoological museum of the Moscow State University (collection number: Z-1). TYPE HOST: Phyllodoce citrina Malmgren, 1865 (Polychaeta: Phyllodocidae). LOCALISATION: Mid-gut. TYPE LOCALITY: White Sea Biological Station of the Moscow State University, Yeremeyevsky Rapid, Velikaya Salma Strait, Kandalaksha Bay, White Sea.     

(α-Pyridyl) methyl phosphoro-bis-triazolide as a new phosphorylating reagent for internucleotide bond formation

(α-Pyridyl)methyl phosphoro-bis-triazolide has been found to be a reagent of choice for phosphate protection in oligodeoxyribonucleotide synthesis. The reagent has been used successfully to phosphorylate all the four 5’-and N-protected deoxynucleosides. The resulting 3′-phosphorylated derivatives were found to be fairly stable as either triethyl ammonium salts or cyanoethyl derivatives. The phosphorylated derivatives were used in the preparation of the dimers T_pT and d(A_pT) in solution phase and a tetramer, TTTT, and a hexamer, d(ATATAT), on solid phase using glass support. The method gave excellent yields. Considerably reduced condensation time (6–9 min) and practically no cleavage of the internucleotide bond during the removal of the group are the advantages. Presented at the 3rd National Symposium on Bioorganic Chemistry, 1987, Hyderabad.     

A new reagent for preparing radioactively labeled nucleoside derivatives.

The identification of benzimidazole incorporated into RNA of Escherichia coli as benzimidazole nucleoside by means of mass spectrometry is reported. Trimethylsilylation of an enzymatic digest of bacterial RNA allowed the separation of the different nucleosides by gas chromatography. The coupled mass spectrometer was used as a mass specific detector and allowed the sensitive detection of single components of the complex mixture. Thus, benzimidazole ribonucleoside could be detected in hydrolysates of RNA from E. coli fed benzimidazole in the culture broth, although this nucleoside could not be completely separated from uridine by the gas chromatographic systems explored. Quantitation of the benzimidazole nucleoside content revealed that benzimidazole is incorporated into RNA amounting to 16% relative to adenosine.     

1-(t-Butyldimethylsilyloxy) benzotriazole (TBDMS-OBt): A new and novel reagent for the synthesis of peptides

Summary Synthesis and use of 1-(t-butyldimethylsilyloxy)benzotriazole (TBDMS-OBt) in the coupling of Fmoc-amino acid chlorides to amino free amino acid esters in homogeneous solution phase is described. The coupling required no addition of base and was fast and racemization free. Work up and isolation of products were easy. Yield, purity and¹H NMR analysis of peptides, synthesised by this method, were satisfactory.     

1-(t-Butyldimethylsilyloxy) benzotriazole (TBDMS-OBt): A new and novel reagent for the synthesis of peptides

Synthesis and use of 1-(t-butyldimethylsilyloxy)benzotriazole (TBDMS-OBt) in the coupling of Fmoc-amino acid chlorides to amino free amino acid esters in homogeneous solution phase is described. The coupling required no addition of base and was fast and racemization free. Work up and isolation of products were easy. Yield, purity and ¹H NMR analysis of peptides, synthesised by this method, were satisfactory.