Presence of 3,4-dihydroxyphenylalanine-containing peptides in hemocytes of the ascidian,Halocynthia roretzi

Summary Five 3,4-dihydroxyphenylalanine (DOPA)-containing peptides have been isolated from hemocytes of the ascidian,Halocynthia roretzi. Three of them were composed of DOPA, proline, phenylalanine, histidine and arginine in different ratios, while the other two contained only DOPA and an unidentified amino acid. DOPA-containing peptides were found to exist in only one type of hemocyte.     

Effects of plant lectins on cellular defense reactions of ascidian hemocytes

The effects of plant lectins on the three cellular defense reactions of hemocytes of the solitary ascidian,Halocynthia roretzi (hemocyte aggregation, phagocytosis, and an allogenic reaction), were investigated. Concanavalin A inhibited aggregation, while wheat germ agglutinin and ricin inhibited the allogenic reaction. Neither of the lectins showed inhibitory effects on phagocytosis, but ricin promoted phagocytosis. These effects of the lectins were diminished by the addition of sugars specific for the respective lectins. These results strongly suggest that different surface carbohydrates are involved in the recognition mechanisms of threeH. roretzi cellular defense reactions.     

Staurosporine aglycone (K252-c) and arcyriaflavin A from the marine ascidian,Eudistoma sp

Staurosporine aglycone (K252-c) (compound1) and arcyriaflavin A (2) were isolated from a specimen of the marine ascidian,Eudistoma sp., collected off the coast of West Africa. In addition to expressing micromolar and submicromolar inhibition of enzyme activity against seven protein kinase C isoenzymes and inhibition of proliferation of the human lung cancer A549 and P388 murine leukemia cell lines,1 also inhibited cell adhesion of the EL-4.IL-2 cell line and expressed activity in the K562 bleb and neutrophil assays.     

Bioactive marine metabolites. VIII. Isolation of an antimicrobial blue pigment from the bryozoanBugula dentata

Summary An antimicrobial blue pigment, which is identical with a tetrapyrrole from a bacterium, was isolated from the bryozoanBugula dentata.     

New tamjamine class alkaloids from the marine ascidianAtapozoa sp. and its nudibranch predators. Origin of the tambjamines inAtapozoa

Summary Two new tambjamine class alkaloids, possessing ichthyodeterrent properties, have been isolated from the organic extracts of the marine ascidianAtapozoa sp. and its nudibranch predators. The structure of the new metabolites were elucidated through interpretation of their physical and spectral data and by comparison with spectral data for related compounds. Microscopic examination ofAtapozoa considering the yellow color of the tambjamines suggested thatAtapozoa is capable of the de novo biosynthesis of these metabolites.     

The effect of corticotropin-releasing factor and pro-opiomelanocortin-derived peptides on the phagocytosis of molluscan hemocytes

The effect of corticotropin-releasing factor (CRF) and pro-opiomelanocortin (POMC)-derived peptides on hemocyte phagocytosis in two molluscs,Planorbarius corneus andViviparus ater was studied. The peptides and related fragments examined are those which have been shown to influence hemocyte motility in the two species. The results obtained revealed that the effects on phagocytosis are not directly correlated with previous findings on cell motility. Furthermore, the mode of action of an individual peptide could be species-specific and dose-dependent. The relationships between peptides, locomotion and phagocytosis in these molluscs are discussed.     

Inhibitory effect of bacterial ubiquinones on the settling of barnacle,Balanus amphitrite

In an attempt to clarify the influence of marine bacteria on the settling of fouling invertebrate larvae, we screened for inhibitors, produced by marine bacteria, of settling by cyprids of the barnacle,Balamus amphitrite. We found that the culture broth ofAlteromonas sp. strain number KK10304, which was associated with the marine sponge,Halichondria okadai, effectively inhibited settling of the cyprids. Bioassay-guided isolation indicated ubiquinone-8 (1) as an effective inhibitor of cyprid settling. As ubiquinones are widely distributed in bacteria, several related compounds were also tested.     

The enhanced induction of metallothionein by zinc, its half-life in the marine fish Pleuronectes platessa, and the influence of stress factors on metallothionein levels

Intraperitoneal injection of zinc raised levels of a hepatic metallothionein-like species. Assuming that this species was metallothionein (MT) then levels were raised from approximately 20 micrograms/g to 300 micrograms/g in 7 days, and levels thereafter remained high for the next 4 weeks. The half-lives of the protein in liver and kidney from starved fish, measured using in vivo incorporation of 35S cysteine at 11 degrees C, were approximately 27 days and 32 days respectively. The following agents failed to stimulate synthesis of MT in plaice: stress (due to catching), endotoxin, dexamethasone, cortisol and turpentine.     

Protective effect of Shigyaku-to,a traditional Chinese herbal medicine,on the infection of herpes simplex virus type 1 (HSV-1) in mice

The antiviral activity of Shigyaku-to (TJS-109), a traditional Chinese herbal medicine, was investigated in mice infected with herpes simplex virus type 1 (HSV-1). TJS-109 is a combination of the medicinal plant extracts fromZingiberis siccatum rhizoma,Aconiti tuber andGlycyrrhizae radix in a specific proportion. Mice infected with a 10 LD₅₀ dose of HSV-1 were treated with TJS-109 orally at doses of 1.25 to 20 mg/kg 2 days before, and 1 and 4 days after the infection. The treated groups had 80% (1.25 mg/kg), 40% (5 mg/kg) and 23% (20 mg/kg) mortality rates 25 days after the infection as compared with a 100% mortality rate in control mice treated with saline. When HSV-1 infected mice (recipients) received CD8⁺T cell fractions derived from spleens of mice treated with TJS-109 (donors), 70% of recipients survived, as compared with 0% survivors in the groups of mice treated with saline, B cell fractions, CD4⁺ T cell fractions or macrophage-enriched fractions prepared from the same donors. TJS-109 did not show any virucidal activities against HSV-1 or any virostatic activities on the growth of HSV-1 in Vero cells. These results suggest that TJS-109 protected mice exposed to lethal amounts of HSV-1 through the activation of CD8⁺ T cells.     

Comparison of the ototoxic effect of kanamycin on albino and pigmented rats,studied using an operant method

Summary A study was made of the effect of daily administration of kanamycin (400 mg kg^–1) on the hearing of Wistar albino and Lister hooded (pigmented) rats, which had been conditioned to discriminate an acoustic signal. In all animals except one, the drug caused severe, permanent hearing impairment and there was no difference between albino and pigmented rats in onset or degree. Other work has suggested a mediatory role for melanin pigment in such drug ototoxicity but the significance of this must be questioned in view of the failure to find any differences in functional deficit.This work was supported by a Fellowship toE. S. Harpur from the Department of Health and Social Services (Northern Ireland).     

Comparison of the ototoxic effect of kanamycin on albino and pigmented rats, studied using an operant method.

A study was made of the effect of daily administration of kanamycin (400 mg kg-1) on the hearing of Wistar albino and Lister hooded (pigmented) rats, which had been conditioned to discriminate an acoustic signal. In all animals except one, the drug caused severe, permanent hearing impairment and there was no difference between albino and pigmented rats in onset or degree. Other work has suggested a mediatory role for melanin pigment in such drug ototoxicity but the significance of this must be questioned in view of the failure to find any differences in functional deficit.     

Effects of the light-dark cycle and scheduled feeding on behavioral and reproductive rhythms of the cyprinodont fish,Medaka,Oryzias latipes

Summary Medaka were maintained on a 168 light-dark cycle and fed once daily on one of 5 different feeding schedules. The daily rhythm of agonistic behavior rapidly entrained to the scheduled feeding time and maintained this entrainment during a 3-day starvation period. In contrast the daily rhythms of egg laying and courtship stayed entrained to the L:D cycle regardless of the feeding schedule. Thus, temporal integration of this fish with its daily environment can involve multistimuli which concurrently and differentially entrain externally expressed circadian systems.We thank Mark Goodrich and Steve Huber for fish maintenance and technical assistance; and Don Dovala for aid in developing the automatic feeder. The research was funded in part by NIH, AM 25191 and NIEHS, ES No. 01985.     

Novel cytotoxic peptides from the tropical marine cyanobacteriumHormothamnion enteromorphoides 1. Discovery,isolation and initial chemical and biological characterization of the hormothamnins from wild and cultured material

A Caribbean cyanobacterium,Hormothamnion enteromorphoides, was found to produce a complex mixture of ichthyotoxic peptides, perhaps explaining the apparent absence of predation upon these potentially palatable life forms. Bioassay-guided fractionation was used to isolate these toxic and antimicrobial natural products, and a variety of techniques including HR FAB mass spectrometry, 2D-NMR, traditional hydrolysis-amino acid analysis, and several chemical reactions were used to define the basic structural features of the major peptide, hormothamnin A. Hormothamnin A is a cyclic undecapeptide containing six common and five uncommon or new amino acid residues. HPLC analyses indicate that the relative proportions of these peptide natural products remain relatively constant between different collection locations and years, however, they do vary seasonally. Clonal isolates of this cyanobacterium in culture produce the full spectrum of toxic peptides.     

The effect of thyroid state,adrenaline and glucose on the release of free fatty acids from adipose tissue

Zusammenfassung Die Freisetzung freier Fettsäuren aus dem mesenterialen Fettgewebe von Ratten ist bei hyperthyroiden Tieren grösser, bei hypothyreoiden geringer und wird besonders bei hyperthyreoiden Ratten durch Adrenalin positiv gesteigert. Glukose beeinflusst die durch Adrenalin gesteigerte Abgabe der freien Fettsäuren aus dem Fettgewebe von euthyreoiden Tieren nicht, setzt diese jedoch bei hyperthyreoiden Ratten herab.     

The enhanced induction of metallothionein by zinc,its half-life in the marine fishPleuronectes platessa,and the influence of stress factors on metallothionein levels

Summary Intraperitoneal injection of zinc raised levels of a hepatic metallothionein-like species. Assuming that this species was metallothionein (MT) then levels were raised from approximately 20 g/g to 300 g/g in 7 days, and levels thereafter remained high for the next 4 weeks. The half-lives of the protein in liver and kidney from starved fish, measured using in vivo incorporation of³⁵S cysteine at 11°C, were approximately 27 days and 32 days respectively. The following agents failed to stimulate synthesis of MT in plaice: stress (due to catching), endotoxin, dexamethasone, cortisol and turpentine.     

The effect of the phytoalexins,lubimin, (−)-maackiain,pinosylvin, and the related compounds dehydroloroglossol and hordatine M on human lymphoblastoid cell lines

Summary We have tested the effect of the phytoalexins lubimin, (–)-maackiain and pinosylvin and the related compounds dehydroloroglossol and hordatine M on the growth of the human lymphoblastoid cell lines Molt and Raji. (–)-maackiain, pinosylvin and dehydroloroglossol showed significant growth inhibitory action on the cells. Suppression of [³H] thymidine and [³H] leucine uptake was tested and noted in pinosylvin and dehydroloroglossol. The phytoalexins and related compounds are widespread in plants and provide a potential source of antineoplastic substances.We would like to acknowledge the assistance of J. Hux in preparing the phytoalexins and related compounds. This work was supported by a grant from National Health and Welfare Canada. Correspondence to Dr. L. Skinnider, Department of Pathology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7M OWO.     

The effect of isoforms of the cell polarity protein, human ASIP, on the cell cycle and Fas/FasL-mediated apoptosis in human hepatoma cells

Human ASIP (hASIP) is expressed as numerous alternative splicing isoforms and there is an atypical protein kinease C (aPKC) phosphorylation site in exon 17b of the encoded sequence. We have identified an important role for exon 17b in cancer cells. Our results showed that hASIP-sa and sb had different effects on cell growth and Fas/FasL-mediated apoptosis in BEL-7404 human hepatoma cells. Human ASIP-sa modified the S phase of the cell cycle and might stimulate cell proliferation. Growth inhibition by hASIP-a antisense oligonucleotide-confirmed the positive action of hASIP-sa. Compared with hASIP-sa, hASIP-sb accelerated Fas/FasL-induced apoptosis, examined by sub-G1 accumulation, chromatin condensation, nuclear fragmentation, PARP cleavage, caspase-8 degradation and mitochondria- regulated cell death. Treatment with aPKC inhibitor could enhance Fas/FasL-mediated apoptosis in hASIP-sa-overexpressing cells, suggesting that hASIP-sa and its interaction with aPKC might contribute to the malignant growth and the blocking of Fas/FasL-mediated apoptosis, while hASIP-sb might function as an antagonist of hASIP-sa.Received 24 March 2005; received after revision 31 May 2005; accepted 21 June 2005