Methyl Jasmonate Induces Gums and Stimulates Anthocyanin Accumulation in Peach Shoots

The effect of methyl jasmonate (JA-Me) on the induction of gum was studied in relation to the action of ethylene in peach (Prunus persica Batsch cv. Benishimizu) shoots. JA-Me applied at concentrations of 0.1–2.5% (w/w) in lanolin paste to current growing or older shoots substantially induced gums 3 days after treatment. The amount of gums exuded increased depending on the dose of JA-Me. Ethephon (2-chloroethyl- phosphonic acid) at 1 or 2% (w/w) in lanolin induced gum and strongly enhanced the promoting effect of JA-Me on gum formation. JA-Me also induced anthocyanin accumulation in current growing shoots, but ethephon did not. Anthocyanin accumulation in response to JA-Me at a concentration of 10 mg/liter or higher was observed also in the cut shoots of peach. Ethephon (100 mg/liter) substantially inhibited anthocyanin accumulation induced by JA-Me. These facts suggest that JA-Me plays an important role in gum formation as well as ethylene and in anthocyanin accumulation and that these processes are not necessarily accompanied by each other in peach shoots. Received January 26, 1998; accepted March 4, 1998     

Enrichment of Presenilin 1 Peptides in Neuronal Large Dense-Core and Somatodendritic Clathrin-Coated Vesicles

Abstract: Presenilin 1 is an integral membrane protein specifically cleaved to yield an N-terminal and a C-terminal fragment, both membrane-associated. More than 40 presenilin 1 mutations have been linked to early-onset familial Alzheimer disease, although the mechanism by which these mutations induce the Alzheimer disease neuropathology is not clear. Presenilin 1 is expressed predominantly in neurons, suggesting that the familial Alzheimer disease mutants may compromise or change the neuronal function(s) of the wild-type protein. To elucidate the function of this protein, we studied its expression in neuronal vesicular systems using as models the chromaffin granules of the neuroendocrine chromaffin cells and the major categories of brain neuronal vesicles, including the small clear-core synaptic vesicles, the large dense-core vesicles, and the somatodendritic and nerve terminal clathrin-coated vesicles. Both the N- and C-terminal presenilin 1 proteolytic fragments were greatly enriched in chromaffin granule and neuronal large dense-core vesicle membranes, indicating that these fragments are targeted to these vesicles and may regulate the large dense-core vesicle-mediated secretion of neuropeptides and neurotransmitters at synaptic sites. The presenilin 1 fragments were also enriched in the somatodendritic clathrin-coated vesicle membranes, suggesting that they are targeted to the somatodendritic membrane, where they may regulate constitutive secretion and endocytosis. In contrast, these fragments were not enriched in the small clear-core synaptic vesicle or in the nerve terminal clathrin-coated vesicle membranes. Taken together, our data indicate that presenilin 1 proteolytic fragments are targeted to specific populations of neuronal vesicles where they may regulate vesicular function. Although full-length presenilin 1 was present in crude homogenates, it was not detected in any of the vesicles studied, indicating that, unlike the presenilin fragments, full-length protein may not have a vesicular function.     

Genetic structure, isolation and characterization of a Bacillus licheniformis cell wall hydrolase.

Summary A DNA fragment containing the gene for a cell wall hydrolase of Bacillus licheniformis was cloned into Escherichia coli. Sequencing of the fragment showed the presence of an open reading frame which encodes a polypeptide of 253 amino acids with a molecular mass of 27 513. The gene was designated as cwlM, for cell wall lysis. The deduced amino acid sequence indicated that there is a repeated sequence consisting of 33 amino acid residues in the C-terminal region. Deletion of the C-terminal region did not lead to any loss of cell wall lytic activity. The gene product purified from E. coli cells harboring a cwlM-bearing plasmid exhibited a M _r value of 29 kDa on SDS-polyacrylamide gels, and characterization of the specific substrate bond cleaved by CWLM indicated that the enzyme is an N-acetylmuramoyl-l-alanine amidase (EC 3.5.1.28). The enzyme hydrolyzed the cell wall of Micrococcus luteus more efficiently than those of B. licheniformis and B. subtilis, but the truncated CWLM (lacking the C-terminal region) had lost this preference. CWLM prepared from B. subtilis cells harboring a plasmid containing cwlM had a similar M _r value to that from E. coli. Amino acid sequence homologies between CWLM and other amidases, and their protein structures are discussed.     

Functional Structure of the Oxygen-Evolving Unit of Photosystem II as Determined by Radiation Inactivation

The size of the complex that is essential for the electron-transferactivity from the oxygen-evolving center to the secondary electronacceptor, Q_B, is about 250 kDa, as determined by target-sizeanalysis after the radiation inactivation of functions of photosystemII (PS II). Inter-Chl tranfer of excitation energy was insensitiveto the radiation inactivation indicating that the masses ofCP47, CP43, and light-harvesting Chi a/b proteins are not includedin the functional size of the oxygen-evolving PS II complex.The transfer of electrons from the secondary electron donor,Z, to Q_B was catalyzed by a unit of only 65 kDa. The sizes ofthe complexes involved in these light-induced functions of PSII were dependent on the intensity of actinic light. Under saturatingintensities of light, the functional size of the complex fortransfer of electrons from Z to Q_B was 38 kDa, with a correspondingdecrease in the size of the oxygen-evolving PS II from 250 kDato 125 kDa [Takahashi, Mano and Asada (1985) Plant Cell Physiol.26: 383]. The protein of about 30 kDa functions in the photoreductionof the pheophytin molecule, as well as in the electron transferfrom Z to Q_A. Under low-intensity light, complexes having thesame sizes as those of the basal functional complexes undersaturating-intensity light are further required, probably tostabilize separated charges in the PS II reaction center andthe oxygen-evolving center. (Received June 20, 1990; Accepted September 18, 1990)     

Characterization of new microsatellite loci in Pieris amamioshimensis (Ericaceae), a species nearly extinct in the wild

A set of 11 polymorphic microsatellite markers has been developed and characterized for the critically endangered species Pieris amamioshimensis. Fifty‐nine individuals of an ex‐situ population were used to identify these markers. The total number of alleles for each locus ranged from 3 to 9, with an average of 5.4. The expected heterozygosities (H_S) and observed heterozygosities (H_O) ranged from 0.47 to 0.77 and 0.22 to 0.88, respectively. In total, four loci exhibited significant deviations from Hardy–Weinberg equilibrium: two loci showed significant heterozygosity excess and the other two loci showed significant heterozygosity deficit. The polymorphism information content (0.43 ≤ PIC ≤ 0.73), the probability of exclusions (PE₁ = 0.9565, PE₂ = 0.9969 and PE₃ = 0.9999) and probabilities for identity (PI = 3.78 × 10^?9 and PI‐Sib = 2.35 × 10^?4) suggest that these markers are useful for estimating not only genetic diversity but also parentage, for the ex‐situ conservation management of populations.     

Dimeric hydroanthracenes from the unripe seeds of Cassia torosa

From the unripe seeds of Cassia torosa three new dimeric hydroanthracene derivatives were isolated along with stigmasterol, sitosterol, campesterol, physcion-9-anthrone, torosachyrsone and the phlegmacins A₂ and B₂. The structures of the new derivatives were established as physcion-10, 10′-bianthrone, anhydrophlegmacin B₂ [2-(6′-methoxy-3′-methyl-3′, 8′, 9′-trihydroxy-1′-oxo-1′, 2′, 3′, 4′-tetrahydroanthracene-10′-yl)-1, 8-dihydroxy-3-methoxy-6-methyl-9-oxo-9, 10-dihydroanthracene] and torosanin [2-(6′-methoxy-3′-methyl-3′, 8′,9′-trihydroxy-1′-oxo-1′, 2′, 3′,4′-tetrahydroanthracene-5′-yl)-1, 8-dihydroxy-3-methoxy-6-methyl-9-oxo-9, 10-dihydroanthracene], respectively.