| 7586087 |
Improved total synthesis and structure-activity relationship of arenastatin A, a potent cytotoxic spongean depsipeptide |
10.1248/cpb.43.1598. |
Chem Pharm Bull (Tokyo) |
Improved total synthesis and structure-activity relationship of arenastatin A, a potent cytotoxic spongean depsipeptide
Abstract
- An efficient asymmetric synthesis of a cyclic depsipeptide arenastatis A (1) is described. 1, isolated from the marine sponge Dysidea arenaria, exhibited extremely potent cytotoxicity with IC50 of pg/ml for KB cells, and in this context the structure-activity relationship among several stereoisomers of 1 and allied compounds has also been examined.
|
| 7588285 |
Molecular cloning and functional expression of a third isoform of the human calcitonin receptor and partial characterization of the calcitonin receptor gene. |
10.1210/endo.136.12.7588285 |
Endocrinology |
Molecular cloning and functional expression of a third isoform of the human calcitonin receptor and partial characterization of the calcitonin receptor gene.
Abstract
- We have cloned and expressed two isoforms of the human calcitonin (hCT) receptor. Primers designed from the published sequence of a CT receptor cloned from an ovarian small cell carcinoma line were used for the polymerase chain reaction amplification of related products from human breast carcinoma MCF-7 cells. Two complementary DNAs were isolated. One clone lacks a 16-amino acid insert in the first intracellular loop and is virtually identical to the receptor recently cloned from the T47D human breast carcinoma cell line. The second clone is another splice variant lacking both the 16-amino acid insert in the first intracellular domain as well as the first 47 amino acids of the amino-terminus extracellular domain. COS-7 cells transfected with either receptor isoform bound [125I]salmon CT with high affinity and responded to hCT with increases in cAMP. Tissue distribution studies revealed the truncated extracellular domain 1 isoform transcripts in human skeletal muscle, kidney, brain, and lung. Analysis of a hCT receptor genomic clone demonstrated an exon/intron organization similar to that of the porcine CT receptor gene, except for a distinct exon coding for the alternatively spliced insert in the first intracellular domain.
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| 7588717 |
Cell cycle, differentiation and tissue-independent expression of ribosomal protein L37 |
None |
Eur J Biochem |
Cell cycle, differentiation and tissue-independent expression of ribosomal protein L37
Abstract
- A unique human cDNA (hG1.16) that encodes a mRNA of 450 nucleotides was isolated from a subtractive library derived from HeLa cells. The relative expression level of hG1.16 during different cell-cycle phases was determined by Northern-blot analysis of cells synchronized by double-thymidine block and serum deprivation/refeeding. hG1.16 was constitutively expressed during all phases of the cell cycle, including the quiescent phase when even most constitutively expressed genes experience some suppression of expression. The expression level of hG1.16 did not change during terminal differentiation of myoblasts to myotubes, during which cells become permanently post-mitotic. Examination of other tissues revealed that the relative expression level of hG1.16 was constitutive in all embryonic mouse tissues examined, including brain, eye, heart, kidney, liver, lung and skeletal muscle. This was unusual in that expression was not down-modulated during differentiation and did not vary appreciably between tissue types. Analysis by inter-species Northern-blot analysis revealed that hG1.16 was highly conserved among all vertebrates studied (from fish to humans but not in insects). DNA sequence analysis of hG1.16 revealed a high level of similarity to rat ribosomal protein L37, identifying hG1.16 as a new member of this multigene family. The deduced amino acid sequence of hG1.16 was identical to rat ribosomal protein L37 that contained 97 amino acids, many of which are highly positively charged (15 arginine and 14 lysine residues with a predicted M(r) of 11,065). hG1.16 protein has a single C2-C2 zinc-finger-like motif which is also present in rat ribosomal protein L37. Using primers designed from the sequence of hG1.16, unique bovine and rat cDNAs were also isolated by 5'-rapid-amplification of cDNA ends. DNA sequences of bovine and rat G1.16, clones were 92.8% and 92.2% similar to human G1.16 while the deduced amino acid sequences derived from bovine and rat cDNAs each differed by a single amino acid from the sequence of hG1.16 and the published rat L37 sequence. Southern-blot analysis revealed that hG1.16 exists in multiple copies in human, rat and mouse genomes. These G1.16 clones encode unique human, rat and bovine members of the ribosomal protein L37 gene family, which are constitutively expressed even during transitions from quiescence to active cell proliferation or terminal differentiation, in all tissues and all vertebrates investigated.
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| 7592027 |
Anthelmintic profile of the cyclodepsipeptide PF1022A in in vitro and in vivo models |
10.7164/antibiotics.48.820. |
J Antibiot (Tokyo) |
Anthelmintic profile of the cyclodepsipeptide PF1022A in in vitro and in vivo models
Abstract
- A novel cyclodepsipeptide of fungal origin, PF1022A, recently was reported to have anthelmintic activity. To supplement published reports and determine potential utility of PF1022A as a ruminant anthelmintic, the compound was examined in in vitro and in vivo models. Assays used measured motility of Haemonchus contortus (intrinsic drug potency), ATP levels (parasite death), and activity against H. contortus, Ostertagia ostertagi, and Trichostrongylus colubriformis in the jird (spectrum, potency, and efficacy by various routes). The potency of PF1022A in reducing motility is greater than commercial anthelmintics. Examination of ATP levels in PF1022A-paralyzed H. contortus indicates that worms are not killed, suggesting the compound acts as a neurotoxin in nematodes. In the jird, PF1022A has activity orally against each of the parasites studied and at doses comparable to all commercial anthelmintics, except the macrocyclic lactones which are more potent. Unfortunately, for some nematode species, parenteral delivery is ineffective at realistic doses.
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| 7592832 |
Cloning of a cDNA encoding chitotriosidase, a human chitinase produced by macrophages. |
10.1074/jbc.270.44.26252 |
J. Biol. Chem. |
Cloning of a cDNA encoding chitotriosidase, a human chitinase produced by macrophages.
Abstract
- We have recently observed that chitotriosidase, a chitinolytic enzyme, is secreted by activated human macrophages and is markedly elevated in plasma of Gaucher disease patients (Hollak, C. E. M., van Weely, S., van Oers, M. H. J., and Aerts, J. M. F. G. (1994) J. Clin. Invest. 93, 1288-1292). Here, we report on the cloning of the corresponding cDNA. The nucleotide sequence of the cloned cDNA predicts a protein with amino acid sequences identical to those established for purified chitotriosidase. Secretion of active chitotriosidase was obtained after transient transfection of COS-1 cells with the cloned cDNA, confirming its identity as chitotriosidase cDNA. Chitotriosidase contains several regions with high homology to those present in chitinases from different species belonging to family 18 of glycosyl hydrolases. Northern blot analysis shows that expression of chitotriosidase mRNA occurs only at a late stage of differentiation of monocytes to activated macrophages in culture. Our
Results show that, in contrast to previous beliefs, human macrophages can synthesize a functional chitinase, a highly conserved enzyme with a strongly regulated expression. This enzyme may play a role in the degradation of chitin-containing pathogens and can be used as a marker for specific disease states.
|
| 7594610 |
Rat neutrophil defensins. Precursor structures and expression during neutrophilic myelopoiesis |
None |
J Immunol |
Rat neutrophil defensins. Precursor structures and expression during neutrophilic myelopoiesis
Abstract
- Defensins constitute a family of 3- to 4-kDa antimicrobial peptides that are stored in the cytoplasmic granules of neutrophils, some macrophages, and intestinal Paneth cells. We have assessed defensin gene expression during myeloid differentiation by first characterizing cDNAs for each of the four known rat neutrophil defensins (RatNP 1-4). The cDNA sequences revealed that the peptides are synthesized as 87-94 amino acid precursors, each containing signal, pro-, and mature peptide segments. RatNP-3 and -4 mRNAs, but not those for RatNP-1 and -2 or other myeloid defensins, contained unique polypurine tracts located close to the termination codon in the 3' untranslated region. By using cDNA probes and/or riboprobes, we evaluated defensin transcript levels in a variety of tissues and in the full spectrum of neutrophil precursors. By in situ hybridization, defensin mRNAs were localized to neutrophil precursors in the bone marrow, with the highest mRNA levels occurring in promyelocytes and somewhat lower signals occurring in myeloblasts and myelocytes. Defensin mRNAs were not detectable in bands or mature neutrophils, nor at significant levels in tissues other than bone marrow. The accumulation of defensin protein in bone marrow cells was assessed by immunohistochemical staining with anti-RatNP-1 Ab. RatNP 1-4 mRNAs and protein levels were then correlated for each stage of neutrophilic differentiation to reveal the maturational profile of myeloid defensin gene expression in the rat."
|
| 7604207 |
The tumor-selective somatostatin analog, TT2-32 induces a biphasic activation of phosphotyrosine phosphatase activity in human colon tumor cell line, SW620 |
None |
Tumour Biol |
The tumor-selective somatostatin analog, TT2-32 induces a biphasic activation of phosphotyrosine phosphatase activity in human colon tumor cell line, SW620
Abstract
- Somatostatin has been demonstrated to activate phosphotyrosine phosphatases (PTPases) in pancreatic cells. In this work we studied the effect of a tumor-selective somatostatin structural derivative, TT2-32, on the PTPase activity in the SW620 human colon tumor cell line. TT2-32 caused a strong inhibition of cell proliferation. In response to TT2-32 we found a rapid and sustained increase (5-30 min) in PTPase activity showing two maxima at 0.1 and 30 microM concentrations, respectively. During short-term incubation tyrosine kinase activity was much less affected by TT2-32. TT2-32-induced activation of PTPases may be an important early step in the signaling cascade in the inhibition of cell proliferation in colon carcinomas.
|
| 7612013 |
Isolation and characterization of novel antimicrobial peptides, rugosins A, B and C, from the skin of the frog, Rana rugosa |
10.1006/bbrc.1995.1963. |
Biochem Biophys Res Commun |
Isolation and characterization of novel antimicrobial peptides, rugosins A, B and C, from the skin of the frog, Rana rugosa
Abstract
- Three antimicrobial peptides were isolated from the skin of Rana rugosa. The major component, designated rugosin A, consisted of 33 amino acid residues and had structural homology (45%) with brevinin-2 of Rana porosa brevipoda. This peptide strongly inhibited the growth of gram-positive bacteria (e.g. Staphylococcus aureus 209P). The second peptide (rugosin B), a minor component, also had 33 amino acid residues, but was less homologous (33%) with brevinin-2. This peptide exhibited a striking antimicrobial activity against both gram-negative (e.g., Escherichia coli NIHJ) and gram-positive bacterial species. The third one, named rugosin C, composed of 37 amino acid residues, exhibited an antimicrobial activity against gram-positive bacteria. All three peptides had an intramolecular disulfide bond at the C-terminus.
|
| 7623030 |
The novel desmethyldestruxin B2, from Metarhizium anisopliae, that suppresses hepatitis B virus surface antigen production in human hepatoma cells |
10.1021/np50118a007. |
J Nat Prod |
The novel desmethyldestruxin B2, from Metarhizium anisopliae, that suppresses hepatitis B virus surface antigen production in human hepatoma cells
Abstract
- We have examined the antiviral activity of a crude extract prepared from the culture medium of the fungus Metarhizium anisopliae. Eight active destruxins were identified which showed strong suppressive effect on the production of the hepatitis B surface antigen (HBsAg) in human hepatoma Hep3B cells. One new compound, desmethyldestruxin B2 1, was isolated from M. anisopliae. This structure was determined based on its nmr and mass spectral data.
|
| 7625791 |
In vitro evaluation of the pneumocandin antifungal agent L-733560, a new water-soluble hybrid of L-705589 and L-731373 |
10.1128/AAC.39.5.1070. |
Antimicrob Agents Chemother |
In vitro evaluation of the pneumocandin antifungal agent L-733560, a new water-soluble hybrid of L-705589 and L-731373
Abstract
- Lipopeptide L-733560 is a hybrid analog of L-731373 and L-705589. All are water-soluble semisynthetic pneumocandin Bo derivatives. In vitro susceptibility testing of L-705589, L-731373, and L-733560 against more than 200 clinical isolates consisting of eight Candida species, Cryptococcus neoformans, and three Aspergillus species was performed by the broth microdilution methods. All three pneumocandins exhibited potent anti-Candida activity and moderate anti-C. neoformans activity. However, anti-Aspergillus activity was demonstrated only by an agar disk diffusion method. Antifungal agent-resistant Candida species and C. neoformans showed susceptibility comparable to that of susceptible isolates. Growth inhibition kinetic studies against Candida albicans revealed fungicidal activity within 3 to 5 h. Drug combination studies with pneumocandins and amphotericin B revealed indifferent activity against C. albicans and additive effects against C. neoformans and Aspergillus fumigatus. The activities of the compounds were not dramatically affected by the presence of serum. Resistance induction studies showed that the susceptibility of C. albicans MY1055 was not significantly altered by repeated exposure to subinhibitory concentrations of L-733560. Erythrocyte hemolysis studies indicated minimal hemolytic potential with pneumocandins. Results from preclinical evaluations and development studies performed thus far indicate that the pneumocandins should be safe, broad-spectrum fungicidal agents and potent parenteral antifungal agents.
|
| 7625792 |
Evaluation of water-soluble pneumocandin analogs L-733560, L-705589, and L-731373 with mouse models of disseminated aspergillosis, candidiasis, and cryptococcosis |
10.1128/AAC.39.5.1077. |
Antimicrob Agents Chemother |
Evaluation of water-soluble pneumocandin analogs L-733560, L-705589, and L-731373 with mouse models of disseminated aspergillosis, candidiasis, and cryptococcosis
Abstract
- The activities of the water-soluble pneumocandin derivatives L-733560, L-705589, and L-731373 were evaluated in mouse models of disseminated aspergillosis, candidiasis, and cryptococcosis and were compared with those of commercially available antifungal agents. Pneumocandins are inhibitors of 1,3-beta-D-glucan synthesis. In the aspergillosis model, L-733560 and L-705589 significantly prolonged the survival of DBA/2N mice challenged intravenously with Aspergillus fumigatus conidia. L-733560 and L-705589 exhibited efficacies comparable to that of amphotericin B (AMB) with 90% effective doses of 0.48, 0.12, and 0.36 mg/kg of body weight, respectively. Two mouse models of disseminated candidiasis were used to evaluate these compounds. In both models, mice were challenged intravenously with Candida albicans. In a C. albicans survival model with DBA/2N and CD-1 mice, the efficacy of L-733560 was comparable to that of AMB, while L-731373 and L-705589 were somewhat less active. In a previously described C. albicans target organ kidney assay, the pneumocandin analogs and AMB at doses of > or = 0.09 mg/kg were effective in sterilizing kidneys, while fluconazole and ketoconazole were considerably less active and did not sterilize kidneys when they were used at concentrations of < or = 100 mg/kg. Although orally administered L-733560 showed activity in both candidiasis models, its efficacy was reduced compared with that of parenterally administered drug. In a disseminated cryptococcosis mouse model that measures the number of CFU of Cryptococcus neoformans per gram of brain and spleen, L-733560 at 10 mg/kg was ineffective in reducing the counts in organs, while AMB at 0.31 mg/kg sterilized the organs. These results indicate that the pneumocandins may be beneficial as potent parenterally administered therapeutic agents for disseminated aspergillosis and candidiasis.
|
| 7626780 |
The codon usage of the nisZ operon in Lactococcus lactis N8 suggests a non-lactococcal origin of the conjugative nisin-sucrose transposon |
10.3109/10425179509030968. |
DNA Seq |
The codon usage of the nisZ operon in Lactococcus lactis N8 suggests a non-lactococcal origin of the conjugative nisin-sucrose transposon
Abstract
- An 11.6 kb area downstream from the structural gene of nisin Z in the conjugative nisin-sucrose transposon of Lactococcus lactis subsp. lactis N8 was cloned and sequenced. Analysis of the sequence revealed eight open reading frames, nisZBTClPRK, followed by a putative rho-independent terminator (delta G degrees = -4.7 kcal/mol). The C-terminal hydrophilic domain of the NisK protein is homologous to the C-termini of several histidine kinases of bacterial two-component regulator systems, such as SpaK from Bacillus subtilis and KdpD and RcsC of Escherichia coli. The nisin Z biosynthetic genes were highly similar with the genes of the nisin A operons having, however, a 0-3% difference in the amino acid sequences of the individual proteins. The codon usage of eleven genes within the same conjugative transposon was calculated and found to be strikingly different from that of other lactococcal genes. This, together with the low GC-content (32%) compared to the 38% (G+C) of the lactococcal chromosome in general strongly suggests a non-lactococcal origin of this transposon.
|
| 7628604 |
The structure of porcine protegrin genes |
10.1016/0014-5793(95)00633-k. |
FEBS Lett |
The structure of porcine protegrin genes
Abstract
- We cloned the genes of three protegrins, a family of cathelin-associated antimicrobial peptides originally isolated from porcine leukocytes. Each gene comprised 4 exons and 3 introns, wherein Exon I encoded the signal sequence and the first 37 amino acids of cathelin, Exons II and III contained 36 and 24 additional cathelin residues and Exon IV contained the final two cathelin residues followed by the protegrin sequence. This quadripartite gene structure helps explain how structurally diverse antimicrobial peptides can be expressed on common, cathelin-containing precursors. Southern blot probed with an oligonucleotide specific for protegrin genes suggested that several identical or nearly identical protegrin genes were densely clustered in the pig chromosome.
|
| 7633471 |
Insect immunity: isolation of three novel inducible antibacterial defensins from the vector mosquito, Aedes aegypti |
10.1016/0965-1748(95)00043-u. |
Insect Biochem Mol Biol |
Insect immunity: isolation of three novel inducible antibacterial defensins from the vector mosquito, Aedes aegypti
Abstract
- The injection of Escherichia coli and Micrococcus luteus into the hemocoel of Aedes aegypti induces a potent antibacterial activity in the hemolymph. We have purified and fully characterized three 40-residue antibacterial peptides from the hemolymph of bacteria-challenged mosquitoes that are absent in naive mosquitoes. The peptides are potently active against Gram-positive bacteria and against one of the Gram-negative bacteria that were tested. The amino acid sequences clearly show that the three peptides are novel isoforms of the insect defensin family of antibacterial peptides. They differ from each other by one or two amino acid residues. We present here the complete amino acid sequences of the three isoforms and the activity spectrum of the predominant Aedes defensin.
|
| 7642577 |
Action of alpha-amanitin during pyrophosphorolysis and elongation by RNA polymerase II |
10.1074/jbc.270.32.19114. |
J Biol Chem |
Action of alpha-amanitin during pyrophosphorolysis and elongation by RNA polymerase II
Abstract
- Using defined elongation complexes formed on dC-tailed templates with Drosophila RNA polymerase II, we have examined elongation, pyrophosphorolysis, and DmS-II-mediated transcript cleavage and the inhibitory effect of alpha-amanitin on these processes. Analysis of pyrophosphorolysis on soluble or immobilized and templates confirmed that NTPs are liberated instead of dinucleotides that are released during DmS-II-mediated transcript cleavage. 10 microgram/ml alpha-amanitin completely inhibited DmS-II-mediated transcript cleavage but allowed extended pyrophosphorolysis and nucleotide addition to occur. alpha-Amanitin dramatically decreased the Vmax for nucleotide addition but only slightly affected the Km for nucleotides. Although the processes ae mechanistically distinct, both pyrophosphorolysis and DmS-II-mediated transcript cleavage frequently resulted in similar patterns of shortened transcript. Since polymerase molecules encounter similar kinetic barriers during both processes, it is possible that there is a common step in the reverse movement of the polymerase.
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