Accumulation of tartaric acid in the ripening process of grapes

1. 1. Tartaric acid content in grapes gradually increased withripening and reached a plateau about 50 days after flowering.
2. 2. Tartaric acid synthesis from ^14C0₂ was predominant in anearly ripening stage. When the berries were exposed to ^14CO₂8 days after flowering and examined two days later, 30% of thetotal ¹⁴C fixed was found in tartaric acid. Subsequently, apart of the tartaric acid decomposed, but the greater part remainedin the berries in a salt form. At the last stage of the ripeningprocess (82-100 days after flowering), some of the tartaratewas again converted to free acid. No ^14CO₂ was incorporatedinto tartaric acid when berries were exposed 61 days after flowering.
3. 3. L(+)-Tartaric acid-l,4-¹⁴C fed to the berries was catabolizedto ¹⁴CO₂. The ratio of radio activity recovered as ^{14 CO₂} tothat fed was nearly constant throughout the ripening process.
4. The cause of tartaric acid accumulation in grape berries isnot thought to be due to a lack of catabolizable enzymes, butto formation of an insoluble salt which is scarcely effectedby such enzymes.

(Received May 2, 1968; )     

一种提高质粒DNA凝胶电泳检测灵敏度的方法

比较了凝胶电泳示检测质粒ＤＮＡ时不同激发波长对ＤＮＡ－ＥＢ荧光强度的影响,发现短波长激发光可增加ＤＮＡ的探测灵敏度。采用２６０ｎｍ作为激光光时可探测到少至０．７ｎｇ的线性ＤＮＡ。且在很广的ＤＮＡ的质量范围内,ＤＮＡ－ＥＢ荧光强度 与ＤＮＡ量或正比。以此改进方法检测电离辐射诱导的ＤＮＡ单、双链断裂岢得到与其它研究结果相一致的Ｇ（ＳＳＢ）和Ｇ（ＤＳＢ）值。     

Assessment of the methane mitigation potentials of alternative water regimes in rice fields using a process‐based biogeochemistry model

Rice production is a substantial source of atmospheric CH₄, which is second only to CO₂ as a contributor to global warming. Since CH₄ is produced in anaerobic soil environments, water management is expected to be a practical measure to mitigate CH₄ emissions. In this study, we used a process‐based biogeochemistry model (DNDC‐Rice) to assess the CH₄ mitigation potentials of alternative water regimes (AWR) for rice fields at a regional scale. Before regional application, we tested DNDC‐Rice using site‐scale data from three rice fields in Japan with different water regimes. The observed CH₄ emissions were reduced by drainage of the fields, but were enhanced by organic amendments. DNDC‐Rice gave acceptable predictions of variation in daily CH₄ fluxes and seasonal CH₄ emissions due to changes in the water regime. For regional application, we constructed a GIS database at a 1 × 1 km mesh scale that contained data on rice field area, soil properties, daily weather, and farming management of each cell in the mesh, covering 3.2% of the rice fields in Japan's Hokkaido region. We ran DNDC‐Rice to simulate CH₄ emissions under five simulated water regimes: the conventional water regime and four AWR scenarios with gradually increasing drainage. We found that AWR can reduce CH₄ emission by up to 41% compared with the emission under conventional water regime. Including the changes in CO₂ and nitrous oxide emissions, potential mitigation of greenhouse gas (GHG) was 2.6 Mg CO₂ Eq. ha^?1 yr^?1. If this estimate is expanded to Japan's total rice fields, expected GHG mitigation is 4.3 Tg CO₂ Eq. yr^?1, which accounts for 0.32% of total GHG emissions from Japan. For a reliable national‐scale assessment, however, databases on soil, weather, and farming management must be constructed at a national scale, as these factors are widely variable between regions in Japan.     

Clusiidae (Diptera) from log emergence traps in the Yambaru, a subtropical forest of Japan

Five species of Clusiidae (Diptera), Craspedochaeta biseta (Hendel), hendeli a plumosa (Sasakawa), Heteromeringia sexramifera Sueyoshi, Phylloclusia yambarensis sp. n., and Sobarocephala uncinata Sueyoshi, were collected from log emergence traps installed in a subtropical forest of Japan from February 2006 to February 2008. Craspedochaeta biseta (Hendel) was newly recorded in Japan. Wood debris was gathered from 1–22 year old secondary stands managed by the improvement cutting of natural forest (ICNF) and unmanaged stands, and categorized by stage of decay and size, and then enveloped in fine net bags (emergence trap). In total, 84 clusiid adults were obtained. Most were reared from wood debris in an advanced stage of decay and from 2 year old or older managed and unmanaged forest stands, although P. yambarensis was reared from wood debris in an early stage of decay and from 1 year old forests after cuttings. Log emergence traps effectively sample clusiids, taking both sexes in approximately equal numbers. Specimens collected by this trap may resolve the difficulty in identifying male and female specimens of several clusiid species that show sexual dimorphism.     

Molecular evidence for repeated hybridization events involved in the origin of the genus × Crepidiastrixeris (Asteraceae) using RAPDs and ITS data

We investigated the hybrid origin of × Crepidiastrixeris denticulato-platyphylla using RAPDs and ITS sequence data. The putative parents Paraixeris denticulata and Crepidiastrum platyphyllum represent separate species, irrespective of geographical origin. The occurrence of species specific RAPD markers from P. denticulata and C. platyphyllum in × C. denticulato-platyphylla established unambiguously a hybrid origin between the two taxa. This was in line with the occurrence of a combination of morphological characters such as plant habit and floret numbers. The parent taxa differed from each other by 7 nucleotide substitutions and 2 indel events in the ITS region. The hybrids showed sequence additivity and most likely represent F₁ plants, with the exception of two plants which were of possible F₂ origin, possessing either the ITS sequences of one parent only, or one predominant ITS type. The hybrids occurred in two out of three localities where the parents occurred sympatrically. This fact, together with the short life-span of the plants, suggests that × C. denticulato-platyphylla exists as a result of repeated, frequent hybridization between the parent species.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 333–343.     

Molecular evidence for phytosiderophore‐induced improvement of iron nutrition of peanut intercropped with maize in calcareous soil

Peanut/maize intercropping is a sustainable and effective agroecosystem that evidently enhances the Fe nutrition of peanuts in calcareous soils. So far, the mechanism involved in this process has not been elucidated. In this study, we unravel the effects of phytosiderophores in improving Fe nutrition of intercropped peanuts in peanut/maize intercropping. The maize ys3 mutant, which cannot release phytosiderophores, did not improve Fe nutrition of peanut, whereas the maize ys1 mutant, which can release phytosiderophores, prevented Fe deficiency, indicating an important role of phytosiderophores in improving the Fe nutrition of intercropped peanut. Hydroponic experiments were performed to simplify the intercropping system, which revealed that phytosiderophores released by Fe‐deficient wheat promoted Fe acquisition in nearby peanuts and thus improved their Fe nutrition. Moreover, the phytosiderophore deoxymugineic acid (DMA) was detected in the roots of intercropped peanuts. The yellow stripe1‐like (YSL) family of genes, which are homologous to maize yellow stripe 1 (ZmYS1), were identified in peanut roots. Further characterization indicated that among five AhYSL genes, AhYSL1, which was localized in the epidermis of peanut roots, transported Fe(III)–DMA. These results imply that in alkaline soil, Fe(III)–DMA dissolved by maize might be absorbed directly by neighbouring peanuts in the peanut/maize intercropping system.     

Size-dependent reproductive dominance in foundresses of Ropalidia plebeiana, an Australian paper wasp forming nest aggregations (Hymenoptera: Vespidae)

The relationship between reproductive status and body size in foundresses of Ropalidia plebeiana, an Australian endemic paper wasp forming huge aggregations of nests, was examined. Foundresses with developed ovaries (laying foundresses) in multifoundress colonies tended to be larger than foundresses in single‐foundress colonies and foundresses with undeveloped ovaries (non‐laying foundresses). However, the laying foundress was not always the largest of the foundresses in a colony. Body shape in foundresses varied according to simple allometric growth, while foundresses and first brood females diverged in their growth parameters in the preimaginal stage.     

Histone modification and signalling cascade of the dormancy‐associated MADS‐box gene,PpMADS13‐1, in Japanese pear (Pyrus pyrifolia) during endodormancy

Dormancy‐associated MADS‐box (DAM) genes play an important role in endodormancy phase transition. We investigated histone modification in the DAM homolog (PpMADS13‐1) from Japanese pear, via chromatin immunoprecipitation–quantitative PCR, to understand the mechanism behind the reduced expression of the PpMADS13‐1 gene towards endodormancy release. Our results indicated that the reduction in the active histone mark by trimethylation of the histone H3 tail at lysine 4 contributed to the reduction of PpMADS13‐1 expression towards endodormancy release. In contrast, the inactive histone mark by trimethylation of the histone H3 tail at lysine 27 in PpMADS13‐1 locus was quite low, and these levels were more similar to a negative control [normal mouse immunoglobulin G (IgG)] than to a positive control (AGAMOUS) in endodormancy phase transition. The loss of histone variant H2A.Z also coincided with the down‐regulation of PpMADS13‐1. Subsequently, we investigated the PpMADS13‐1 signalling cascade and found that PpCBF2, a pear C‐repeated binding factor, regulated PpMADS13‐1 expression via interaction of PpCBF2 with the 5′‐upstream region of PpMADS13‐1 by transient reporter assay. Furthermore, transient reporter assay confirmed no interaction between the PpMADS13‐1 protein and the pear FLOWERING LOCUS T genes. Taken together, our results enhance understanding of the molecular mechanisms underlying endodormancy phase transition in Japanese pear.     

Isolation and characterization of polymorphic microsatellite loci in Asiatic sand sedge,Carex kobomugi Ohwi (Cyperaceae)

Fourteen polymorphic microsatellite loci were isolated from Asiatic sand sedge, Carex kobomugi Ohwi (Cyperaceae), a clonal perennial herb predominant in sandy coast vegetation in Japan. Polymorphism was surveyed for 24 ramets within a single population and for eight distinct individuals from six populations. Within a population, between two and eight alleles were found per locus, and expected heterozygosity ranged from 0.041 to 0.720. Among populations, a higher level of polymorphism was observed. The microsatellite loci were shown to be useful for the study of spatial genetic structure at fine scale and genetic differentiation among populations.     

SHORT COMMUNICATION Cyclic Nucleotides inFrankiaand Symbiotic Nodules

Cyclic adenosine 3',5'-monophosphate (cAMP) and cyclic guanosine3',5'-monophosphate (cGMP) contents of cultured cells ofFrankiastrainsoriginally isolated from nodules ofAlnus sieboldiana, MyricarubraandElaeagnus macrophyllawere measured by enzyme immunoassays(EIA).Frankiacells, cultured for 59–121 d, had cAMP contentsranging from 2.9 to 76.1 pmol mg^-1protein and cGMP contentsranging from 0.9 to 5.2 pmol mg^-1protein. FollowingFrankiaculture,the media contained extremely large quantities of cAMP and significantlevels of cGMP. The nature of accumulation and secretion ofcyclic nucleotides by slow-growingFrankiacells was comparableto that by a fast-growing actinomyceteStreptomyces lividansTK24,suggesting that secretion of cAMP byFrankiacells may occur throughthe cell membrane but not by cell lysis. cAMP and cGMP contentsin the symbiotic nodules, leaves and roots of actinorrhizalplants and leaves of non-actinorrhizal trees were also measured.The nodules of actinorrhizal woody plants(A. sieboldiana, E.macrophylla, E. umbellata, E. pungensandM. rubra)had cAMP contentsranging from 4 to 258 pmol g^-1f. wt and cGMP contents rangingfrom 1.1 to 5.2 pmol mg^-1protein. Most leaves and some rootsof actinorrhizal plants and all the leaves of non-actinorrhizalwoody plants examined contained small but significant amountsof cAMP and cGMP. This is the first report of significant contentsof cAMP and cGMP in culturedFrankiacells andFrankia-infectednodules. Possible roles of cyclic nucleotides as symbiotic signalsare discussed.Copyright 1998 Annals of Botany Company cAMP, cGMP, actinorrhizal plants, nodules,Frankia,symbiosis.