Metabolism of 3α, 7α-dihydrexy-7β-methyl-5β-cholanoic acid and 3α,7β-dihydroxy-7α-methyi-5β-cholanoic acid in hamsters

The metabolic fate of the bile add analogs, 3α,7α-dihydroxy-7β-methyl-5β-cholanoic acid and 3α,7β-dihydroxy-7α-methyl-5β-cholanoic acid, was investigated and compared with that of chenodeoxycholic acid in hamsters. Both bile acid analogs were absorbed rapidly from the intestine and excreted into bile at similar to that of chenodeoxycholic acid. In the strain of hamster studied, the biliary bile were conjugated with both glycine and taurine. After continuous intravenous infusion, chenodeoxycholic acid the analogs became the major bile acid constituents in bile. After oral administration of a single dose of these compounds, fecal analysis revealed the existence of unchanged material (25–35%) as well as considerable amounts of metabolites (65–75%). The major metabolites excreted into feces were more polar than the starting material and were tentatively identified as trifaydroxy-7-methyl compounds by radioactive thin-layer chromatography. However, monohydroxy compounds were also found in the fecal extracts. These results show that chenodeoxycholic acid and ursodeoxycholic acid with a methyl group at the 7-position are resistant to bacterial 7-dehydroxylation than the normally occurring bile acids and that a certain proportion of these analogs is hydroxylated to give the corespondiag trihydroxy compound(s), In a control experiment, about 5% of administered chenodeoxychoulic acid was metabolized to a trihydroxy feile acid, but most of the compound (95%) was transformed into lithocholic acid.     

Effect of taurocholate on the conversion of 3α, 7α, 12α-Trihydroxy-5β-Cholestan-26-OIC acid into cholic acid

To determine if the conversion of the intermediate, 3α, 7α, 12α-trihydroxy-5β-cholestan-26-oic acid (THCA), into cholic acid is influenced by taurocholate, two rats were infused intravenously with [³H] THCA until they reached a steady state. Taurocholate was then added and infused at a rate of 1 μmole/min/rat for 48 hours. The percentage of [³H] THCA recovered in the bile did not increase indicating that taurocholate does not suppress the conversion of THCA into cholic acid.     

Synthesis and Properties of Phosphorylated 3′-O-β-D-Ribofuranosyl-2′-deoxythymidine

Abstract

A strategy was developed for the synthesis of 3′-O-β-D-ribofuranosyl 2′-deoxythymidine derivatives using three different protecting groups, which allows the synthesis of a phosphoramidite building block for oligonucleotide synthesis. Likewise the 5′-O- and 5″-O-phosphorylated analogues were synthesized and their conformation was determined using NMR spectroscopy.     

Synthesis and Properties of the Oligonucleotide N3′ →P5′ Phosphoramidates

Abstract

Uniformly modified oligonucleotide N3′ → P5′ phosphoramidates were synthesized. The prepared N3′ → P5′ phosphoramidates form extremely stable duplexes and triplexes with complementary nucleic acids. Moreover, these compounds are highly resistant to enzymatic hydrolysis by snake venom phosphodiesterase and cellular nucleases and they show high antisense activity in vitro and in vivo.     

Transformation of lithocholic acid to a new bile acid, 3α, 15β-dihydroxy-5β-cholanic acid by Cunninghamella blakesleeana ST-22

Summary A fungus identified as Cunninghamella blakesleeana (Lendner) can carry out 15-hydroxylation of lithocholic acid to a new bile acid (3,15-dihydroxy-5-cholanic acid). By optimizing the fermentation conditions, the amount of the product increased from 0.17 g/l to 1.2 g/l. Hydrophilicity measurements and in vitro cholesterol solubilization tests showed that 3, 15-dihydroxy-5-cholanic acid was as effective as ursodeoxycholic acid in cholesterol solubilization.Abbreviations LCA lithocholic acid (3-hydroxy-5-cholanic acid) - 3, 15-DHC (3, 15-dihydroxy-5-cholanic acid) - DMSO dimethyl sulfoxide - CHES 2-[N-cyclohexylamino]ethanesulfonic acid     

On the histochemical demonstration of N-acetyl-β-galactosaminidase

Summary Aging neurons accumulate lipofuscin pigment granules which appear to be secondary lysosomes of the residual body variety. The biological significance of the residual bodies is debated. They were here studied with the aim of testing a hypothesis that the membranes surrounding these granules might be more vulnerable than the membranes around younger types of lysosomes.For this purpose large motor neurons of young and old rats were compared with respect to lysosomal membrane latency, using a modified Bitensky lysosomal lability test. Utilizing successively increasing incubation times, the lysosomes of old neurons, in particular the residual bodies in polar aggregates of old neurons—presumed to represent lipofuscin pigment granules—were found to have a clearly reduced latency in comparison with lysosomes of young neurons.These findings support the notion that the residual bodies are more fragile than younger lysosomes.Supported by the Swedish Medical Research Council (Project No. 12X-2037).     

β-Carbon stereoselectivity of N-carbamoyl-d-α-amino acid amidohydrolase for α,β-diastereomeric amino acids

N-Carbamoyl-d-α-amino acid amidohydrolase (d-carbamoylase) was found to distinguish stereochemistry not only at the α-carbon but also at the β-carbon of N-carbamoyl-d-α-amino acids. The enzyme selectively acted on one of the four stereoisomers of N-carbamoyl-α,β-diastereomeric amino acids. This simultaneous recognition of two chiral centers by d-carbamoylase was useful for the fine stereoselective synthesis of α,β-diastereomeric amino acids such as threonine, isoleucine, 3,4-methylenedioxyphenylserine and β-methylphenylalanine. The stereoselectivity for the β-carbon was influenced by the pH of the reaction mixture and by the bulk of the substituent at the β-carbon. Received: 18 June 1999 / Received revision: 30 July 1999 / Accepted: 6 August 1999     

Effectiveness of N,N′-Bis(2-hydroxy-5-methylbenzyl) ethylenediamine-N,N′-diacetic acid (HJB) to supply iron to dicot plants

Iron chlorosis is commonly corrected by the application of EDDHA chelates, whose industrial synthesis produces o,oEDDHA together with a mixture of regioisomers and other unknown by-products. HJB, an o,oEDDHA analogous, is a new chelating agent with a purer synthesis pathway than EDDHA. The HJB/Fe³⁺ stability constant is intermediate between the racemic and meso o,oEDDHA/Fe³⁺ stereoisomers. This work studied the efficacy of HJB as a Fe source in plant nutrition. No significant differences between o,oEDDHA/Fe³⁺, HJB/Fe³⁺ and HBED/Fe³⁺ were observed when they are used as substrates of the iron-chelate reductase of mild chlorotic cucumber plants. Chelates prepared with the stable isotope ⁵⁷Fe were used in both soil and hydroponic experiments. In the hydroponic experiment, nutrient solutions with low doses of chelates were renewed weekly. Soybean plants treated with o,oEDDHA/⁵⁷Fe³⁺ recorded the highest results in biomass, SPAD index and Fe nutrition. In the soil experiment, chelates were added once at a rate of 2.5 mg Fe per kg of a calcareous soil. Soybean plants treated with HJB/⁵⁷Fe³⁺ recorded a higher biomass and SPAD index in young leaves than the plants treated with o,oEDDHA/⁵⁷Fe³⁺; however, ⁵⁷Fe and total Fe concentrations in leaves were lower. The results of both pot experiments are associated with a faster ability by o,oEDDHA to provide Fe to the plants and with a more continuous supply of Fe from HJB/Fe³⁺. HJB/⁵⁷Fe³⁺ effectively alleviated the Fe-deficiency chlorosis of soybean with a longer lasting effect than o,oEDDHA/⁵⁷Fe³⁺.     

Effect of N,N′-bis (alkyldimethyl)-α,ω-alkanediammonium dibromides on bacteria of the genusclostridium

Antibacterial effect of 17 ammonium compounds of the type of N,N′-bis(alkyldimethyl)-α,ω-alkanediammonium dibromides was tested on anaerobically sporulating bacteria of the genusClostridium. A sizable antibacterial activity was displayed by five N,N′-bis(alkyldimethyl)-1,6-hexanediammonium dibromides and by four N,N′-bis(decyldimethyl)-α,ω-alkanediammonium dibromides. These compounds exhibited activity higher than, or comparable with, that of the reference standards Ajatin and Septonex. The maximum antibacterial activity was found in compounds whose alkyl chain contained 9–12 carbon atoms. Compounds with a lower number of carbon atoms in the chain (less than 8) exhibited a low activity.     

Spectral differentiation of 3,3′-di-O-methylellagic acid from 4,4′-di-O-methylellagic acid

3,3′-and 4,4′-di-O-methylellagic acid were synthesized, and their spectra (IR, UV, ¹³CFT-NMR) were compared with each other. UV and ¹³C FT-NMR spectra were the most useful for distinguishing them.     

Syntheses and antitumor activities of N′1,N′3-dialkyl-N′1,N′3-di-(alkylcarbonothioyl) malonohydrazide: The discovery of elesclomol

A series of N′¹,N′³-dialkyl-N′¹,N′³-di(alkylcarbonothioyl) malonohydrazides have been designed and synthesized as anticancer agents by targeting oxidative stress and Hsp70 induction. Structure–activity relationship (SAR) studies lead to the discovery of STA-4783 (elesclomol), a novel small molecule that has been evaluated in a number of clinical trials as an anticancer agent in combination with Taxol.     

Synthesis, aggregation behavior and cholesterol solubilization studies of 16-epi-pythocholic acid (3α,12α,16β-trihydroxy-5β-cholan-24-oic acid)

Synthesis, aggregation behavior and in vitro cholesterol solubilization studies of 16-epi-pythocholic acid (3α,12α,16β-trihydroxy-5β-cholan-24-oic acid, EPCA) are reported. The synthesis of this unnatural epimer of pythocholic acid (3α,12α,16α-trihydroxy-5β-cholan-24-oic acid, PCA) involves a series of simple and selective chemical transformations with an overall yield of 21% starting from readily available cholic acid (CA). The critical micellar concentration (CMC) of 16-epi-pythocholate in aqueous media was determined using pyrene as a fluorescent probe. In vitro cholesterol solubilization ability was evaluated using anhydrous cholesterol and results were compared with those of other natural di- and trihydroxy bile acids. These studies showed that 16-epi-pythocholic acid (16β-hydroxy-deoxycholic acid) behaves similar to cholic acid (CA) and avicholic acid (3α,7α,16α-trihydroxy-5β-cholan-24-oic acid, ACA) in its aggregation behavior and cholesterol dissolution properties.     

Calcium-loaded 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid blocks cell-to-cell diffusion of carboxyfluorescein in staminal hairs of Setcreasea purpurea

The effect of microinjected calcium-loaded 1,2-bis(2-aminophenoxy) ethane-N,N,N,N-tetraacetic acid (CaBAPTA) on cell-to-cell diffusion of carboxyfluorescein (CF) was examined in staminal hairs of S. purpurea Boom. The CaBAPTA was microinjected into the cytoplasm of the staminal hairs either with CF or prior to a subsequent microinjection of CF. The cell-to-cell diffusion of CF along the hair was monitored using enhanced-fluorescence video microscopy. Cytoplasmic streaming stopped in cells treated with CaBAPTA, indicating that intracellular Ca²⁺ had increased. Cell-to-cell diffusion of CF was blocked in cells treated with Ca-BAPTA. An inhibition of cytoplasmic streaming and cell-to-cell diffusion was observed in the cells adjoining the CaBAPTA-microinjected cell, indicating that the Ca-BAPTA appeared to pass through plasmodesmata. While cytoplasmic streaming resumed 5–10 min after CaBAPTA treatment, cell-to-cell diffusion did not resume until 30–120 min later. These data support an involvement of calcium in the regulation of cell-to-cell communication in plants.Abbreviations BAPTA 1,2-bis(2-aminophenoxy)ethane-N,N,N, N-tetraacetic acid - CF carboxyfluorescein This work was supported by Professional Staff Congress-City University (PSC-CUNY) of New York grant No. 667180 and U.S. Department of Agriculture grant No. 87-CRCR-1-244.     

Cortisone-evoked decrease of acid-β-galactosidase, β-glucuronidase, N-acetyl-β-glucosaminidase and arylsulphatase in the ileum of suckling rats

Changes of activity of intestinal acid beta-galactosidase, beta-glucuronidase, N-acetyl-beta-glucosaminidase and arylsulphatase were studied in suckling rats treated with cortisone (5mg/100g body wt. daily, started on day 9 postnatally) and compared with changes in control animals. Specific activities were not changed within the first 72h, but all enzymes decreased similarly 96h after the first injection. Total activities per ileum and animal were not changed within the first 48h, but within 72h a significant decrease was observed. Calculation of the rate of decrease of the hydrolases studied in cortisone-treated animals shows that it proceeds faster than the rate of renewal of enterocytes in this period.     

1β,7β-Dihydroxydehydroabietic acid,a new biotransformation product of dehydroabietic acid by Aspergillus niger

Microbial transformation of dehydroabietic acid by Aspergillus niger afforded the new derivative 1β,7β-dihydroxydehydroabietic acid and the known 1β-hydroxy and 7β-hydroxy derivatives. The structures were elucidated by spectroscopic methods. The compounds were assessed towards Gram (+) and Gram (−) bacteria and showed a weak antimicrobial effect. This revised version was published online in August 2006 with corrections to the Cover Date.     

β-N-oxalyl-L-α,β-diaminopropionic acid regulates mitogen-activated protein kinase signaling by down-regulation of phosphatidylethanolamine-binding protein 1

β-N-Oxalyl-L-α,β-diaminopropionic acid (l-ODAP) an α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor agonist activates protein kinase C in white leghorn chick brain. The current study focuses on the protein kinase C downstream signaling targets associated with L-ODAP excitotoxicity in SK-N-MC human neuroblastoma cells and white leghorn male chick (Gallus domesticus) brain extracts. L-ODAP treatment in SK-N-MC cells (1.5 mM) and chicks (0.5 mg/g body weight) results in a decreased expression and increased phosphorylation of phosphatidylehthanolamine-binding protein 1 (PEBP1) up to 4 h which however, returns to normal by 8 h. D-ODAP, the non-toxic enantiomer however, did not affect PEBP1 levels in either chick brain or SK-N-MC cells. Decreased PEBP1 expression correlated with subsequent activation of Raf-1, MEK and ERK signaling components of the mitogen-activated protein kinase cascade and nuclear translocation of hypoxia inducible factor-1α (HIF-1α) in chick brain nuclear extracts and SK-N-MC cells. SK-N-MC cells over-expressing PEBP1 inhibited nuclear translocation of HIF-1α when treated with l-ODAP, indicating that down-regulation of PEBP1 is responsible for HIF-1α stabilization and nuclear localization. Excitotoxicity of L-ODAP may thus be the result of phosphorylation and down-regulation of PEBP1, a crucial signaling protein regulating diverse signaling cascades. L-ODAP induced convulsions and seizures in chicks could be the result of a hypoxic insult to brain.     

Synthesis and Biological Properties of 2′-5′ Oligodeoxyribonucleotide,an Isomer of Biologic DNA

Abstract

Oligonucleotide having 2′-5′ phosphodiester linkage has been synthesised on solid support using indigenously prepared 3′-deoxy-2′-phosphoramidites. The 2′-5′ oligonucleotide showed higher half-life when subjected to 3′-exonuclease, SVPD, digestion. This oligonucleotide formed a stable duplex with complementary RNA but not with DNA. Similarly, it did not form triplex as well either with DNA or RNA duplex.