Formation of Chlorophyll-Protein Complexes during Greening. 2. Redistribution of Chlorophyll among Apoproteins

The formation of Chl-protein complexes (CPs) in cucumber cotyledonsduring a dark period after a brief illumination was studied.SDS-PAGE analysis showed that the P700-Chl a-protein complex(CP1) and Chl a-protein complex of the PS II core (CPa) increased,with a concomitant decrease in the light-harvesting Chl a/6-proteincomplex of PS II (LHCII), during 24-h dark incubation of cotyledonsafter 6h of continuous illumination. In agreement with theseresults, curve analysis revealed that spectral components characteristicof CP1 and CPa increased while those of Chi b decreased duringthe dark incubation. Since Chl is not synthesized in the dark,Chl must be released from LHCII and re-incorporated into CP1and CPa. The amounts of apoproteins of CP1 and 43 kDa protein(one of the apoproteins of CPa) increased during the dark incubation,and the increase could be inhibited by chloramphenicol (CAP).CP1 did not increase in the dark when tissues were incubatedwith CAP which inhibited the synthesis of apoproteins of CP1,indicating that CP formation by Chl redistribution needs newlysynthesized apoproteins. The decrease in LHCII apoproteins duringdark incubation was inhibited by CAP probably because Chl wasnot removed from LHCII by apoproteins of CP1 and CPa, whosesynthesis was blocked by the presence of CAP. When intermittently-illuminatedcotyledons containing a little LHCII were incubated with CaCl₂in the dark, Chl b and LHCII apoproteins accumulated with thedisappearance of 43 kDa protein; Chl of 43 kDa protein may beutilized for LHCII formation. We concluded that Chl moleculesonce bound with their apoproteins are redistributed among theapoproteins. (Received October 17, 1990; Accepted December 6, 1990)     

Javanicinosides D-H, quassinoid glucosides from Picrasma javanica

From Picrasma javanica, five new quassinoid glucosides, javanicinosides D-H, together with known quassinoids, neoquassin and picrasin A and triterpenoids, hispidol A and lanosta-7,24-dien-3-one were isolated. The structures have been determined by spectral analysis and chemical evidence.     

A simple procedure for the isolation of pure nuclei from carrot embryos in synchronized cultures

A simple method is presented for the isolation of nuclei from somatic embryos of carrot (Daucus carota L.), which is applicable to small amounts of material in synchronized culture. The method employs buffers containing a high concentration of glycerol to stabilize the structure of the nuclei. Purification was carried out by centrifugation using preformed Percoll gradients. Treatment with cell wall-degrading enzymes prior to homogenization improved the efficiency of isolation and permitted a reproducible yield of nuclei. The pure preparations were obtained with an efficiency of approximately 60%. The isolated nuclei retained their morphological characteristics as demonstrated by phase — contrast and electron microscopy. Nuclear proteins displayed the expected species of histones by two-dimensional gel electrophoresis. The isolated nuclei showed high RNA polymerase activity.     

Production of a high concentration acetic acid by Acetobacter aceti using a repeated fed-batch culture with cell recycling

Summary The acetic acid concentration in a batch culture of Acetobacter aceti M23 increased up to 90 g/l by adding ethanol intermittently. Although the bacterial cells ceased growth at about 60 g acetic acid/l, non-viable cells still preserved ethanol oxidation activity. Cell recycling by filtration in a repeated fed-batch culture increased the overall acetic acid production rate 2.84-fold compared to that without cell recycling for the purpose of obtaining an acetic acid concentration of 80.8 g/l. Repeated fed-batch cultivation with cell recycle was effective for increasing the production rate of acetic acid and obtaining high amounts close to a lethal concentration (90 g/l).Offprint requests to: Kiyoshi Toda     

Induction of distamycin A-inducible rare fragile sites and increased sister chromatid exchanges at the fragile site

Summary Expression of distamycin A-inducible rare fragile sites by AT-specific DNA-ligands was examined in lymphoblastoid cell lines derived from heterozygous carriers for the fra(8)(q24), fra(16)(pl2), and fra(16)(q22) sites. The sensitivity of fragile site expression to the inducers was different at these fragile sites. The expression of fra(8)(q24) was induced markedly by Hoechst 33258, but not by distamycin A or berenil. An increased expression of fra(16)(p12) was found following treatment with Hoechst 33258 or berenil, but not with distamycin A. At fra(16)(q22), distamycin A markedly induced the fragile site, but Hoechst 33258 and berenil did not. Since their response to the different inducers was similar to that found in cultured lymphocytes, lymphoblastoid cell lines appear to retain their inherent properties. Although BrdUrd alone did nto induce any fragile sites, concomitant treatment with BrdUrd plus the inducer was synergistically effective in inducing all the fragile sites. An increased frequency of sister chromatid exchanges was observed at fra(16)(p12) following simultaneous treatment with BrdUrd and berenil, mainly when the site was expressed as an isochromatid gap. Thus, the induced fra (16)(pl2) site is a hot spot for the formation of sister chromatid exchanges, as found in other reported fragile sites.     

The caste system of the dolichoderine antTechnomyrmex albipes (Hymenoptera: Formicidae): morphological description of queens,workers and reproductively active intercastes

Females ofTechnomyrmex albipes consist of winged queens, intercastes and workers. In established colonies, reproduction is performed by many intercastes (wingless females which have intermediate phenotypes between queen and worker characters). Dissection and morphological examination revealed that intercastes had a spermatheca, but workers did not. Intercastes can be divided into three classes: major intercastes with three ocelli, medium intercastes with one ocellus, and minor intercases without ocelli. Workers have no ocelli. The thoracic structure of intercastes gradually becomes more complex from minors to majors. The body size of intercastes gradually increases from minors to majors, and so does the number of overioles. The body size distributions of minor intercastes and workers overlap considerably, but the distributions of ovariole numbers overlap less. Winged queens had distinctly larger body sizes, more ovarioles and larger spermathecae than intercastes. Most intercastes were inseminated with developed ovaries and appeared to reproduce. The caste system and reproductive division of labour inT. albipes is compared to those of ant species in which permanently wingless females reproduce.     

Close similarity between cultured human omental mesothelial cells and endothelial cells in cytochemical markers and plasminogen activator production

Summary The mesothelial cells obtained from human omental adipose tissue showed a typical cobblestone monolayer and reacted strongly with keratin, but did not have Von Willebrand factor. Ultrastructurally these cells revealed the existence of desmosome-like cell junctions as well as intracellular canaliculi, tubular structures surrounded by microvilli, and tonofilament-like filaments. The mesothelial cells grew much faster in the medium containing epidermal growth factor, actively took up acetylated-low density lipoprotein into their cytoplasm, and released angiotensin-converting enzyme. They also released urokinase-type plasminogen activator, but only half as much as do human umbilical vein endothelial cells; release of tissue-type plasminogen activator was not observed. Inasmuch as the mesothelial cells also released plasminogen activator inhibitor-1, as do human umbilical vein endothelial cells, we could not detect u-PA activity in culture medium. u-PA may play a role in the protection against adhesion among visceral organs. These observations indicate that cultured human mesothelial cells have characteristics closely related to those found in human endothelial cells.     

Fatty acid elongation activity in fibroblasts from patients with adrenoleukodystrophy (ALD)

The activities of microsomal fatty acid elongation and cytoplasmic de novo fatty acid synthesis were measured in human cultured skin fibroblasts. Both activities in fibroblasts from normal controls and patients with adrenoleukodystrophy (ALD) were compared and slight but a significant increase of elongation activities in ALD fibroblasts was demonstrated. On the other hand, there were no significant differences in the fatty acid synthetase activities. In this study, we measured microsomal fatty acid elongation activities in the presence of N-ethylmaleimide, which completely inhibited the activity of contaminating fatty acid synthetase and also the degradation of fatty acids, and made accurate determination of the elongation activities possible.