Continuing studies on the cyanobacterium Lyngbya sp.: isolation and structure determination of 15-norlyngbyapeptin A and lyngbyabellin D.

Re-collections of the cyanobacterium Lyngbya sp. have yielded two more members of the lyngbyapeptin and lyngbyabellin families. The gross structures of 15-norlyngbyapeptin A (1) and lyngbyabellin D (3) were deduced through standard 2D NMR techniques, with the absolute configuration of both elucidated through degradation and comparison with commercially available and synthetic standards.

More kapakahines from the marine sponge Cribrochalina olemda.

Three new kapakahines E-G (1-3) have been isolated from the marine sponge Cribrochalina olemda. Limited quantities of these compounds required not only NMR analysis but also FAB-MS/MS analysis for the structure elucidation. Kapakahine E showed cytotoxicity against P388 murine leukemia cells.

Piperidine alkaloids from Piper methysticum.

Pipermethystine (1), 3alpha,4alpha-epoxy-5beta-pipermethystine (2) and awaine (3) were isolated from the aerial parts of kava (Piper methysticum G. Forster, Piperaceae) and identified by HRMS and NMR spectroscopic analysis. 1 was concentrated in the stem peelings and leaves.

Cell characterization of mononuclear and giant cells constituting pigmented villonodular synovitis.

The aim of this study was to determine the histologic and cellular characteristics of 2 cell types, mononuclear cells (Mos) and multinuclear giant cells (GCs), that predominantly constitute pigmented villonodular synovitis (PVS). Synovial tissues examined in this study were obtained from 10 patients with PVS. Five methods were used for cell analysis: (1) enzyme-histochemistry for tartrate-resistant acid phosphatase (TRAP); (2) immunohistochemistry using antibodies for CD68, macrophage colony-stimulating factor (M-CSF), MIB-1, p53, p21, p16, and cathepsin-L (cath L); (3) TdT-mediated deoxyuridine triphosphate-biotin terminal end labeling (TUNEL) as a measure of apoptosis; (4) fluorescence-based polymerase chain reaction single-strand conformation polymorphism analyses (FPCR-SSCP) to detect p53 gene mutations; and (5) in situ hybridization using gene-specific oligoprobes for matrix metalloproteinase (MMP)-2, MMP-9, receptor activator of nuclear factor kappaB ligand (RANKL), and calcitonin receptor (CTR).

Primary solitary intracranial melanoma in the sylvian fissure: MR demonstration.

We present a rare case of a primary intracranial melanoma originating from leptomeningeal melanoblasts in the sylvian fissure. The mass appeared hyperintense on T1-weighted MR images and hypointense on T2-weighted MR images, reflecting the presence of abundant melanin granules in the tumor. Associated leptomeningeal enhancement suggested a dire prognosis.

Lyngbyaloside B, a new glycoside macrolide from a Palauan marine cyanobacterium, Lyngbya sp.

A Palauan collection of the marine cyanobacterium Lyngbya sp., which had already afforded diverse peptide-based cytotoxins, also yielded a new glycoside macrolide exhibiting slight cytotoxicity. The compound was termed lyngbyaloside B (1) due to its structural analogy to the previously isolated lyngbyaloside (2).

Control of exploitation-exploration meta-parameter in reinforcement learning.

In reinforcement learning (RL), the duality between exploitation and exploration has long been an important issue. This paper presents a new method that controls the balance between exploitation and exploration. Our learning scheme is based on model-based RL, in which the Bayes inference with forgetting effect estimates the state-transition probability of the environment.

Tasiamide, a cytotoxic peptide from the marine cyanobacterium Symploca sp.

The acyclic peptide tasiamide (1) has been isolated from the marine cyanobacterium Symploca sp. The planar structure and absolute stereochemistry of the peptide were deduced by 2D NMR techniques and chiral HPLC. Tasiamide (1) was cytotoxic against KB and LoVo cells with IC(50) values of 0.

Ulongamides A-F, new beta-amino acid-containing cyclodepsipeptides from Palauan collections of the marine cyanobacterium Lyngbya sp.

Six new beta-amino acid-containing cyclic depsipeptides, termed ulongamides A-F (1-6), have been isolated from collections of apratoxin-producing cyanobacteria from Palau. Their planar structures have been determined by NMR spectroscopic techniques. The absolute stereochemistry of the hydroxy acid and all the alpha-amino acid-derived units was ascertained to be S by chiral HPLC analysis of degradation products.

Development of large pseudocysts adjacent to the knee joint in rheumatoid arthritis. Assessment of radiological and histopathological approaches.

Abstract  This study examined the pathogenesis of large pseudocysts adjacent to knee joints in rheumatoid arthritis (RA). The radiological and histopathological features of 17 large subarticular pseudocysts in 12 knee joints of 10 patients were analyzed. Nine of the 10 patients were classified as class 2 according to Steinbrocker's functional class.

Malevamide D: isolation and structure determination of an isodolastatin H analogue from the marine cyanobacterium Symploca hydnoides.

Malevamide D (1), a highly cytotoxic peptide ester, and the known compound curacin D (5) were isolated from a Hawaiian sample of Symploca hydnoides. The structure of 1 was elucidated by spectroscopic analysis including NMR and high-resolution MS/MS. Partial stereochemical assignments of 1 were made by chiral HPLC analysis of acid and base hydrolysates.

New apratoxins of marine cyanobacterial origin from Guam and Palau.

Two collections of the marine cyanobacterium Lyngbya sp. from Guam and Palau that both afforded the potent cytotoxin apratoxin A (1) each yielded different structural analogues with lower degrees of methylation. The new apratoxins, termed apratoxins B (2) and C (3), were evaluated for their in vitro cytotoxicity along with semisynthetic E-dehydroapratoxin A (4) to identify key structural elements responsible for the cytotoxicity and to initiate SAR studies on this novel family of depsipeptides.

Kulokekahilide-1, a cytotoxic depsipeptide from the cephalaspidean mollusk Philinopsis speciosa.

The cytotoxic depsipeptide kulokekahilide-1, which contains two unusual amino acids, 4-phenylvaline and 3-amino-2-methylhexanoic acid, was isolated from the cephalaspidean mollusk Philinopsis speciosa. Structure elucidation of kulokekahilide-1 was carried out by spectroscopic analysis and chemical degradation. The absolute stereochemistry was determined by Marfey analysis for amino acids and chiral HPLC analysis for hydroxy acids.

Isolation and structure determination of obyanamide, a novel cytotoxic cyclic depsipeptide from the marine cyanobacterium Lyngbya confervoides.

Obyanamide (1) was isolated from a variety of the marine cyanobacterium Lyngbya confervoides collected in Saipan, Commonwealth of the Northern Mariana Islands. Gross structure elucidation of this novel cyclic depsipeptide relied on extensive application of 2D NMR techniques. The absolute stereochemistry was deduced by chiral chromatography of the hydrolysis products and comparison with authentic and synthetic standards.

Symplostatin 3, a new dolastatin 10 analogue from the marine cyanobacterium Symploca sp. VP452.

Symplostatin 3 (1), a new analogue of dolastatin 10 (2), has been isolated from a tumor selective extract of a Hawaiian variety of the marine cyanobacterium Symploca sp. VP452. Compound 1 differs from 2 only in the C-terminal unit; the dolaphenine unit is substituted by a 3-phenyllactic acid residue.

Nomofungin: a new microfilament disrupting agent.

A new alkaloid, nomofungin, has been isolated from the fermentation broth of an unidentified endophytic fungus obtained from the bark of Ficus microcarpa L. The structure of nomofungin was determined by application of spectroscopic methods. The absolute stereochemistry of nomofungin was assigned by using the exciton chirality method.

The structure of microcarpalide, a microfilament disrupting agent from an endophytic fungus.

[structure: see text]. A new alkyl-substituted nonenolide, microcarpalide 1, has been isolated from fermentation broths of an unidentified endophytic fungus. Microcarpalide is weakly cytotoxic to mammalian cells and acts as a microfilament disrupting agent.

Cytotoxic cyclic norterpene peroxides from a Red Sea sponge Diacarnus erythraenus.

Investigation of the lipophilic extract of the Red Sea sponge Diacarnus erythraenus revealed one new norsesterterpene cyclic peroxide, aikupikoxide A (1), three new norditerpene cyclic peroxides, aikupikoxide B-D (2-4), and the known norterpene peroxides muqubilin and nuapapuin A methyl ester. In addition, a new sesquiterpene, O-methyl guaianediol, was isolated. Their structures were determined by means of spectroscopic methods.

Effects of paclitaxel on cultured synovial cells from patients with rheumatoid arthritis.

Background: Proliferation of synovial cells is considered to play a key role in rheumatoid arthritis (RA). Using paclitaxel, a unique antineoplastic agent known to suppress collagen-induced arthritis, we conducted an in vitro study of cell kinetics on cultured synovial cells from patients with RA.

Methods: Alterations of the cell cycle of cultured fibroblast-like synovial cells (FLSs) from patients with RA were studied using flow cytometry and laser scanning cytometry.

Total structure determination of apratoxin A, a potent novel cytotoxin from the marine cyanobacterium Lyngbya majuscula.

Apratoxin A (1), a potent cytotoxin with a novel skeleton, has been isolated from the marine cyanobacterium Lyngbya majuscula Harvey ex Gomont. This cyclodepsipeptide of mixed peptide-polyketide biogenesis bears a thiazoline ring flanked by polyketide portions, one of which possesses an unusual methylation pattern. Its gross structure has been elucidated by spectral analysis, including various 2D NMR techniques.

Pitipeptolides A and B, new cyclodepsipeptides from the marine cyanobacterium Lyngbya majuscula.

Two new cyclodepsipeptides have been isolated from a population of the marine cyanobacterium Lyngbya majuscula collected at Piti Bomb Holes, Guam. They appear to be unique to this particular Guamanian collection and have been named pitipeptolides A (1) and B (2). Their structures have been elucidated by spectroscopic techniques and by characterization of degradation products.

Isolation and structure determination of nostocyclopeptides A1 and A2 from the terrestrial cyanobacterium Nostoc sp. ATCC53789.

The isolation and total structure determination of nostocyclopeptides A1 (1) and A2 (2) are described. These cyclic heptapeptides, which possess a unique imino linkage in the macrocyclic ring, are characteristic constituents of the cryptophycin-producing cyanobacterium Nostoc sp. ATCC53789.

'Upenamide: An unprecedented macrocyclic alkaloid from the Indonesian sponge Echinochalina sp.

'Upenamide (1) represents a new class of macrocyclic marine alkaloid possessing both spirooxaquinolizidinone and hemiaminal ring systems. It was isolated from the Indonesian sponge Echinochalina sp. The gross structure of 1 was elucidated by spectroscopic methods and accurate mass measurements.

Isolation and structure of the cytotoxin lyngbyabellin B and absolute configuration of lyngbyapeptin A from the marine cyanobacterium Lyngbya majuscula.

An analogue of the potent microfilament-disrupter lyngbyabellin A (1) has been isolated as a minor metabolite from the marine cyanobacterium Lyngbya majuscula collected at Apra Harbor, Guam. It possesses slightly weaker cytotoxicity than 1 and has been named lyngbyabellin B (2). Primarily NMR spectroscopy was used to determine its structure.

Polyacetylenes from a red sea sponge Callyspongia species.

From the methanolic extract of the Red Sea sponge Callyspongia sp. six new polyacetylenic compounds, aikupikanynes A-F, together with octahydrosiphonochalyne, were isolated and identified. Their structures, which comprise four hydrocarbons, two alcohols, and one unprecedented alpha-hydroxy carboxylic acid, were determined by extensive 1D and 2D NMR studies and mass spectral determinations.