Production of low temperature active lipase from the pink snow mold, Microdochium nivale (syn. Fusarium nivale)

Summary The pink snow mold, Microdochium nivale (syn. Fusarium nivale) SUF 1377 strain produced an extracellular low temperature active lipase during growth at 4°C. The lipase had the highest activity at 20°C, and retained 19% of its maximum activity at 0°C.     

An Endogenous Suppressor of the Defense Response in Pisum sativum

Healthy pea plants contain a substance, tentatively called "endogenoussuppressor", which specifically suppresses the accumulationof pisatin in pea plants that is induced by treatment with CuCl₂or an elicitor from Mycosphaerella pinodes. This suppressorelicits the accumulation of phytoalexins in other legumes, suchas kidney bean, soybean and cowpea. The endogenous suppressorfunctions to delay the accumulation of pisatin, the activationof phenylalanine ammonialyase (PAL) and the accumulation ofmRNAs for PAL and chalcone synthase induced by the elicitorfrom M. pinodes. The substance specifically induces susceptibilityto nonpathogens, such as Mycosphaerella ligulicola and M. melonis,in pea out of four species of legume tested, but the effectis not cultivar-specific. Thus, the endogenous suppressor inhealthy pea plants suppresses a series of self-defense reactionsand induces susceptibility in pea plants in a species-specificmanner, being similar to the exogenous fungal suppressor fromthe pea pathogen, M.pinodes. (Received February 19, 1992; Accepted May 11, 1992)     

Orthovanadate Suppresses Accumulation of Phenylalanine Ammonia-Lyase mRNA and Chalcone Synthase mRNA in Pea Epicotyls Induced by Elicitor from Mycosphaerella pinodes

Orthovanadate delayed accumulation of mRNAs encoding phenylalanineammonia-lyase and chalcone synthase in pea epicotyls inducedby an elicitor from Mycosphaerella pinodes. However, accumulationof mRNA for a putative P-type ATPase was not affected. The relationshipbetweenthe ATPase and defense responses is discussed. ³Present address: Plant Pathology Laboratory, School of Agriculture,Nagoya University, Chikusa, Nagoya, 464-01 Japan.     

Excision and duplication of su3+-transducing fragments carried by bacteriophage φ80: II. Red- or rec-dependent excision and duplication

During vegetative growth φ80)sus2psu3⁺ and φ80int3sus2psu3⁺ segregate su3^? progeny phages, which have lost suppressor activity, at high frequency, even in the absence of the host Rec system. DNA molecules of the su3^? segregants were equivalent to φ80 DNA, as determined by heteroduplex analysis. Loss of suppressor activity is ascribed either to unequal intermolecular crossing-over or to excision by internal recombination between two homologous regions of the phage genome which bracket the bacterial segment containing the su3⁺ gene. To investigate the recombination system acting on the segregation of su3^? phages, a fec^?int^? deletion derivative of φ80sus2psu3⁺, φ80Δ4sus2psu3⁺, has been isolated that is stable even after several cycles of growth in the absence of the host Rec system. However, segregation of su3^? phages from φ80Δ4sus2psu3⁺ was observed when it was complemented in vivo with the hybrid phage λatt⁸⁰imm⁸⁰ in the absence of the host Rec system. The Δ4 deletion is 12.4% of the φ80 genome, starting at a distance of 1.6% φ80 unit to the right from the φ80 crossover point, pp′, i.e. located between 54.6% and 67.0% φ80 unit, as measured from the left (0%) termini of the mature φ80 DNA molecules. By locating the regions of homology between the DNAs of λ and φ80 (Fiandt et al., 1971), the region deleted in φ80Δ4sus2psu3⁺ was assigned to the genes of the phage Red system and a part of the int gene. In the presence of the host Rec system, φ80Δ4-sus2psu3⁺ segregates both phages, φ80Δ4sus2 and φ80Δ4sus2p(su3⁺)₂, which were excised or duplicated for su3⁺-transducing fragments. The loss of the duplication in φ80Δ4sus2p(su3⁺)₂ is also promoted by the host Rec system. Either of two generalized recombination systems, viral Red system or host Rec system, can play a role in the production of the excisions and the duplications of transducing fragments.     

Partial inhibition of protein synthesis accelerates the synthesis of porphyrin in heme-deficient mutants of Escherichia coli

Mutants of Escherichia coli defective in the HemA protein grow extremely poorly as the result of heme deficiency. A novel hemA mutant was identified whose rate of growth was dramatically enhanced by addition to the medium of low concentrations of translational inhibitors, such as chloramphenicol and tetracycline. This mutant (H110) carries mutation at position 314 in the hemA gene, which resulted in diminished activity of the encoded protein. Restoration of growth of H110 upon addition of the drugs mentioned above was due to activation of the synthesis of porphyrin. However, this activation was not characteristic exclusively of cells with this mutant hemA gene since it was also observed in a heme-deficient strain bearing the wild-type hemA gene. The activation did not depend on the promoter activity of the hemA gene, as indicated by studies with fusion genes. It appears that partial inhibition of protein synthesis via inhibition of peptidyltransferase can promote the synthesis of porphyrin by providing an increased supply of Guamyl-tRNA for porphyrin synthesis. Glutamyl-tRNA is the common substrate for peptidyltransferase and HemA.     

The N domain of Smad7 is essential for specific inhibition of transforming growth factor-beta signaling.

Inhibitory Smads (I-Smads) repress signaling by cytokines of the transforming growth factor-beta (TGF-beta) superfamily. I-Smads have conserved carboxy-terminal Mad homology 2 (MH2) domains, whereas the amino acid sequences of their amino-terminal regions (N domains) are highly divergent from those of other Smads. Of the two different I-Smads in mammals, Smad7 inhibited signaling by both TGF-beta and bone morphogenetic proteins (BMPs), whereas Smad6 was less effective in inhibiting TGF-beta signaling. Analyses using deletion mutants and chimeras of Smad6 and Smad7 revealed that the MH2 domains were responsible for the inhibition of both TGF-beta and BMP signaling by I-Smads, but the isolated MH2 domains of Smad6 and Smad7 were less potent than the full-length Smad7 in inhibiting TGF-beta signaling. The N domains of I-Smads determined the subcellular localization of these molecules. Chimeras containing the N domain of Smad7 interacted with the TGF-beta type I receptor (TbetaR-I) more efficiently, and were more potent in repressing TGF-beta signaling, than those containing the N domain of Smad6. The isolated N domain of Smad7 physically interacted with the MH2 domain of Smad7, and enhanced the inhibitory activity of the latter through facilitating interaction with TGF-beta receptors. The N domain of Smad7 thus plays an important role in the specific inhibition of TGF-beta signaling.     

Human-type ABO,MN, and Lewis blood groups,and Gm and Inv factors in several species of macaques

More than 1,000 blood samples were collected from macaques of speciesM. fuscata, M. cyclopis, M. irus, M. mulatta, M. nemestrina, andM. speciosa, and all or a part of them were tested for human-type ABO, MN, and Lewis blood groups, and Gm and Inv factors. Differences between and/or within species analogous to racial differences in man were markedly noted in the distribution of the ABO and Lewis blood groups. Saliva samples from a small number ofM. fuscata were tested quantitatively for the presence of H and Lewis substances, and it was found that almost all the animals were secretors of H, Le^a, and Le^b, independently of the Lewis blood groups of their red cells. Red cells of all macaques tested contained M or M-like, but not N^v(V), antigens, and no polymorphism of MN blood groups was present. Selected plasma samples fromM. fuscata, M. cyclopis, M. irus, andM. nemestrina were found to be negative for all Gm(1), Gm(2), Gm(4), and Inv(1) factors tested.This study was supported in part by the Japan Society for Promotion of Science Grant B-54 and by National Science Foundation Grant FJ 4.11. 1 as part of the Japan-U.S. Cooperative Science Program.