Fallen logs are the main regeneration sites for Abies sachalinensis (Sachalin fir) in subboreal forests in Japan. We surveyed the spatial genetic structure of different demographic stages in a 4.29-ha natural population of A. sachalinensis. Genetic structure was significant at short distances throughout all stages in this wind-dispersed conifer. To evaluate the effects of fallen-log-dependent recruitment on demography and spatial genetic structure, we conducted parentage analysis of offspring with highly polymorphic nuclear simple sequence repeat and chloroplast simple sequence repeat markers, and developed a new hierarchical Bayesian model to estimate the effects of mother trees and fallen logs on seed dispersal and offspring recruitment. Combined application of nuclear and chloroplast simple sequence repeat markers allowed us to unambiguously identify mother trees of most offspring (> 90%). Female reproductive success was extremely skewed; a few adults produced most of the offspring on fallen logs. Limited distance of effective dispersal and recruitment was seen in the parentage analysis and modelling estimation. These recruitment characters of A. sachalinensis, with a fallen-log-dependent recruitment process, may result in significant genetic structure in early demographic stages.

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The observation of microbubbles during RFA can predict the ablated area and might be useful to prevent the unfavorable ablation of adjacent organs and vessels.

Cucumisin is a subtilisin-like serine protease (subtilase) that is found in the juice of melon fruits (Cucumis melo L.). It is synthesized as a preproprotein consisting of a signal peptide, NH 2 -terminal propeptide, and 67-kDa protease domain. We investigated the role of this propeptide (88 residues) in the cucumisin precursor. Complementary DNAs encoding the propeptides of cucumisin, two other plant subtilases (Arabidopsis ARA12 and rice RSP1), and bacterial subtilisin E were expressed in Escherichia coli independently of their mature enzymes. The cucumisin propeptide strongly inhibited cucumisin in a competitive manner with a K i value of 6.2 ؎ 0.55 nM. Interestingly, cucumisin was also strongly inhibited by ARA12 and RSP1 propeptides but not by the subtilisin E propeptide. In contrast, the propeptides of cucumisin, ARA12, and RSP1 did not inhibit subtilisin. region was thought to contribute toward the formation of a proper secondary structure necessary for cucumisin inhibition. This is the first report on the function and structural information of the propeptide of a plant serine protease.Proteases play key roles in diverse processes regulating plant growth, development, and responses to environmental stimuli. They are necessary for protein turnover, strict protein quality control, and degrading specific sets of proteins. Comparative genomics analyses could provide valuable insights into the abundance and roles of various plant protease families. For example, the Arabidopsis thaliana genome has over 550 protease sequences corresponding to almost 3% of the proteome, representing all five catalytic types: serine, cysteine, aspartic acid, metallo, and threonine (1, 2). Of these, serine proteases appear to be the largest class of plant proteases, although protease activity has been demonstrated only by a few of them.Cucumisin (EC 3.4.21.25) is an extracellular thermostable alkaline serine protease that is expressed at high levels in melon fruits (Cucumis melo L.). It comprises more than 10% of the total juice protein and is synthesized in the central parts of the fruits (3). Cucumisin is synthesized and accumulated only in melon fruits, and a cis-regulatory enhancer element in the cucumisin promoter regulates fruit-specific expression of the cucumisin gene (4). We have determined the complete nucleotide sequence of a cucumisin cDNA, the first sequenced plant serine protease, and found that cucumisin is a member of the subtilisin (EC 3.4.21.62) superfamily characterized by a catalytic triad of three amino acids: Asp, His, and Ser (5). The primary structure of cucumisin deduced from the cDNA sequence revealed that it is synthesized as a precursor consisting of four functional domains: a possible signal peptide (22 amino acid residues); NH 2 -terminal prosequence (88 residues); 54-kDa protease domain (505 residues), which is the active enzyme domain of the 67-kDa native cucumisin; and 14-kDa COOHterminal polypeptide (116 residues), which arises by limited autolysis of the 67-kDa native cucumisin (3, 5). The optimal...

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