Inhibitory effect of beta-hydroxyglutamic acid on a molluscan giant neurone.

We found a spontaneously firing neurone, inhibited by beta-hydroxy(erythro)-L-glutamic acid, identified in the subesophageal ganglia of an African giant snail (Achatina fulica Férussac), although this neurone is not sensitive to L-glutamic acid. We suggest that beta-hydroxy(erythro)-L-glutamic acid may be a putative inhibitory synaptic transmitter of the identified molluscan neurone.     

Response of the sawflyDiprion similis to chiral sex pheromones

Summary Males ofDiprion similis respond to both the (+)-2R,3R,7R and (–)-2S,3S,7S enantiomers of its sex pheromone, erythro-3,7-dimethyl pentadecan-2-yl propionate. A mixture of the 2 enantiomers induces a response similar to that of the individual components.Acknowledgments. C.L. was supported by a NERC Fellowship.     

Modification of effects of biologically active peptides,caused by enzyme treatment,on the excitability of identifiable giant neurones of an African giant snail (Achatina fulica Férussac)

Summary Physalaemin, which excites an identifiable molluscan giant neurone (the TAN, tonically autoactive neurone), lost the effect after the trypsin treatment. Unexpectedly, this peptide shows an inhibitory effect on the same neurone after chymotrypsin treatment. Deamino-dicarba-(d-d-)oxytocin and d-d-Arg-vasotocin, which excite another identifiable neurone (the PON, periodically oscillating neurone) continue to show the effect after chymotrypsin treatment (6 h). But d-d-Arg-vasotocin losts the effect on the PON after trypsin treatment.The authors thank Dr Sadaaki Iwanaga of Osaka University and Dr Atsuo Inoue of Daiichi Pharmaceutical Co. for their helpful advice, and Miss Hiroko Tamura for her technical assistance.     

Effect of carbon particles on the recovery of bone marrow stem cells after irradiation in LPS-resistant C3H/HeJ mice

Effect of RES-blockade on bone marrow cells was studied serially after irradiation in LPS-resistant mice. Injection of carbon particles reduced damage and accelerated recovery of marrow hemopoietic stem cells, indicating that LPS-resistant mice can react normally to RES-blockade.     

Granulocytosis induced in vivo by a mouse marrow stromal cell line, BMA1, which produces colony stimulating factor

Nude mice were inoculated with BMA1 cells. These are cells which produce granulocyte-macrophage colony stimulating factor (GM-CSF); They are derived from mouse bone marrow stromal cells transfected with adenovirus 5 DNA. Progressive neutrophilia developed as the tumor grew, but disappeared quickly after local tumor excision. Media conditioned with tumor cells had GM-CSF but neither erythropoietin nor burst-promoting activity. In all the tumors which developed, focal areas of bone formation were found among fibrosarcomatous tissues.     

Misreading of DNA templates containing 8-hydroxydeoxyguanosine at the modified base and at adjacent residues

It has been shown previously that deoxyguanosine residues in DNA are hydroxylated at the C-8 position both in vitro and in vivo to produce 8-hydroxydeoxyguanosine (8-OH-dG) by various agents that produce oxygen radicals such as reducing reagents-O2, metal ions-O2, polyphenol-H2O2-Fe3+, asbestos-H2O2 or ionizing radiation. These agents are mostly either mutagenic or carcinogenic; therefore, the formation of 8-OH-dG can also be considered a likely cause of mutation or carcinogenesis by oxygen radicals. It is of interest to know whether the 8-OH-dG residue in DNA is misread during DNA replication. To answer this question, we have examined the effect of the 8-OH-dG residue in DNA on the fidelity of DNA replication using a DNA synthesis system in vitro with Escherichia coli DNA polymerase I (Klenow fragment). The synthetic oligodeoxynucleotides, with or without an 8-OH-dG residue in a specified position, were chemically synthesized and used as templates for DNA synthesis under the conditions of the dideoxy chain termination sequencing method. Surprisingly, in addition to misreading of the 8-OH-dG residue itself, pyrimidines next to the 8-OH-dG residue (G has not yet been tested) were also misread.     

Effects of ibotenic acid,quisqualic acid and their relatives on the excitability of an identifiable giant neurone of an African giant snail (Achatina fulica Férussac)

Summary An identifiable giant neurone, PON (periodically oscillating neurone), of Achatina fulica Férussac, inhibited by erythro--hydroxy-L-glutamic acid, was also inhibited by 2 relatives of -hydroxy glutamic acid, ibotenic acid and quisqualic acid. These substances similarly showed the effect on the neurone even in the chloride-free medium.The authors wish to thank Professor Emeritus T. Takemoto of Tohoku University, Dr H. Iwasaki of Takeda Chemical Co. and Professor C. H. Eugster of Zurich University for the donation of precious substances, and Miss H. Tamura for technical assistance.