Cytokinin Activity of Benzoylaminodeazapurines, Pentanoylaminodeazapurines and their Corresponding Purine Analogs in Five Bioassays

Cytokinin activities of 6-benzoylamino-1, 6-benzoylamino-3-, 6-pentanoylamino-1- and 6-pentanoylamino-3-deazapurines and their corresponding purine analogs, 6-benzoylaminopurine and 6-pentanoylaminopurine, were examined using five bioassay systems, tobacco callus growth, bud formation on tobacco callus, lettuce seed germination, fresh weight increase of radish cotyledons and retardation of chlorophyll degradation in radish cotyledons. 6-Benzoylamino- and 6-pentanoylamino-1-deazapurines showed stronger cytokinin activity than their corresponding purine analogs in all bioassays used. In tobacco callus growth, 6-benzoylamino-1-deazapurine was nearly as active as zeatin, one of the most active adenylate cytokinins. On the other hand, 6-benzoylamino- and 6-pentanoylamino-3-deazapurines were as active as or less active than corresponding purine analogs.     

Studies on germination of chrysanthemum pollen II. Occurrence of a germinationpromoting substance

The in vitro germination of chrysanthemum pollen is promotedby adding floral organs, excepting anther, to a basal mediumconsisting of sucrose and boric acid. Some other plant organs,such as young fruit of tomato and onion bulb, are also effective.In Chrysanthemum morifolium, the percentage of pollen germinationin the presence of such plant tissues is two to three timesas high as in the control (10 %). In Ch. leucanthemum, it ishigher than 50 %, in contrast to the control in which no germinationis noted. This promotion of germination may be due to a substance extractablefrom the tissues with water, ether or methanol. The promoting substance is not identical with several knowngrowth regulators or with the Ca ion. (Received November 21, 1967; )     

Effects of altered α‐ and β‐branch carotenoid biosynthesis on photoprotection and whole‐plant acclimation of Arabidopsis to photo‐oxidative stress

Functions of α‐ and β‐branch carotenoids in whole‐plant acclimation to photo‐oxidative stress were studied in Arabidopsis thaliana wild‐type (wt) and carotenoid mutants, lut ein deficient (lut2, lut5), n on‐p hotochemical q uenching1 (npq1) and s uppressor of z eaxanthin‐l ess1 (szl1) npq1 double mutant. Photo‐oxidative stress was applied by exposing plants to sunflecks. The sunflecks caused reduction of chlorophyll content in all plants, but more severely in those having high α‐ to β‐branch carotenoid composition (α/β‐ratio) (lut5, szl1npq1). While this did not alter carotenoid composition in wt or lut2, which accumulates only β‐branch carotenoids, increased xanthophyll levels were found in the mutants with high α/β‐ratios (lut5, szl1npq1) or without xanthophyll‐cycle operation (npq1, szl1npq1). The PsbS protein content increased in all sunfleck plants but lut2. These changes were accompanied by no change (npq1, szl1npq1) or enhanced capacity (wt, lut5) of NPQ. Leaf mass per area increased in lut2, but decreased in wt and lut5 that showed increased NPQ. The sunflecks decelerated primary root growth in wt and npq1 having normal α/β‐ratios, but suppressed lateral root formation in lut5 and szl1npq1 having high α/β‐ratios. The results highlight the importance of proper regulation of the α‐ and β‐branch carotenoid pathways for whole‐plant acclimation, not only leaf photoprotection, under photo‐oxidative stress.     

Mass mortality of Japanese macaques in a western coastal forest of Yakushima

The mass mortality of wild Japanese macaques (Macaca fuscata Blyth) was observed in a warm temperate forest of Yakushima, southern Japan. Demographic changes of eight troops between August 1998 and August 1999 were studied and 56% of macaques disappeared from the five intensively studied troops. Mortality varied among troops: two troops became extinct, while another troop did not decrease in size. The rate of mortality of the other troops was between 33 and 80%. The variation in mortality among the troops was either the outcome of local concentrations of mortality or of intertroop competition. The rate of mortality decreased with increasing distance from the two extinct troops and with increasing troop size; these two factors could not be separated statistically. The direct cause of death was diagnosed as pneumonia for four out of five fresh carcasses. The fleshy fruit production in autumn 1998 was the lowest in 14years, and macaques had relied on leaves earlier than in usual years. It was exceptionally hot and dry in the summer of 1998. The exceptionally poor fruit production and hot summer of this year, with the resulting shortage of high-quality foods, was consistent with the scenario that mass mortality was due to the poor nutritional conditions. However, the possibility that epidemics caused the mass mortality cannot be ruled out. Our findings proved that primates in a seemingly stable habitat experience fluctuations in demographic parameters under natural conditions.     

The status of donor cancer tissues affects the fate of patient-derived colorectal cancer xenografts in NOG mice

Patient-derived xenografts (PDXs) of tumors are increasingly becoming important tools for translational research in oncology. The NOD.Cg-Prkdc^scid Il2rg^tm1Sug/Jic (NOG) mouse is an efficient host for PDXs. Thus as a basis for future development of methods to obtain PDXs from various disease types, we have studied the factors that affect the outcome of transplantation of human colorectal cancer in NOG mice. Of the original donor cases examined, 73% had successful engraftment. The outcome of donor-matched tissues was consistent in most cases, and was thought to show that the condition of the host did not affect engraftment. Next we analyzed the tumor aggressiveness in terms of histology grade of the original tumor and found that they were related to engraftment. Detailed histopathological examination of the transplanted tissues strongly indicated that lymphocytes engrafted with the tumor cells affect engraftment. As a factor related to transplantation of lymphocytes, we studied the human IgG concentration in the serum of tumor-bearing mice, but there was no tendency for higher concentrations to result in unsuccessful engraftment. Finally, we studied the type, density and location of T cells in the original donor tissue to determine the immune contexture and found that the unsuccessful engraftment cases tended to have an adequate or coordinated immune contexture compared to successful engraftment cases. From these results, we concluded that the aggressiveness and the T cell infiltration of the original tumor affect the outcome of transplantation in the NOG mouse.     

Morphological and genetic analysis of fish of a Carassius complex (Cyprinidae) in Lake Kasumigaura with reference to the taxonomic status of two all-female triploid morphs

The classification of the Carassius complex (Cyprinidae) including all-female triploids, called ginbuna in Japanese, is so confused that three sympatric morphs of crucian carp in Lake Kasumigaura are categorized into two different subspecies within a species. We examined them in order to explain the coexistence of more than one subspecies and determine the founder of the triploid lineages in the crucian carp fauna in the lake. Principal component analysis proved that the three sympatric morphs had a morphometric basis distinguishable from each other. Ploidy was determined by flow cytometry which showed triploids in two morphs and diploids in the other morph. Stepwise discriminant analysis using only meristic characteristics could separate the diploids from the triploids. Phylogenetic analysis using mitochondrial DNA inferred two lineages in which one was composed of a triploid morph and the other was a diploid–triploid mixture. Disagreement between the taxonomic status and the phylogenetic status is explicable by assuming that the triploids in the Carassius complex had independent origins leading to the different subspecies. C. auratus langsdorfii appears to show genetic complexities that traditional taxonomic classification can not unravel.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 79 , 351–357.     

LIGHT-INDUCED HIGH-AMPLITUDE SWELLING AND SHRINKING IN ISOLATED SPINACH CHLOROPLASTS

It was found that light accelerates the swelling of spinachchloroplasts suspended in a solution containing NaCl and Tris-HCl,and that, in about 60 min, the swollen chloroplasts begin toshrink rapidly. The volume of chloroplasts reached, on swelling,270 per cent of the original volume on the average and thenshrank to 17 per cent. The rate of swelling and the maximumvolume were affected markedly by the tonicity of NaCl. NH₄Cldid not affect the volume changes, while phenazine methosulfateaccelerated the swelling remarkably. The relationship betweenphotoshrinkage and this light-induced high-amplitude swellingwas discussed. (Received April 2, 1966; )     

Nutritional and Hormonal Requirements for the Growth of Vigna sinensis Callus in vitro

Nutritional and hormonal requirements for in vitro growth of callus tissue of Vigna sinensis Endl. were studied. Callus was formed on hypocotyl and root sections, when they were cultured on Linsmaier and Skoog's basal medium solidified with 10 g/1 agar and supplemented with only 0.5 mg/12,4-D or 2 mg/1 IAA. Further addition of 0.2 mg/1 kinetin and 1 g/l yeast extract resulted in more active callus formation. For unlimited vigorous growth of subcultured callus which was originally isolated from root sections, yeast extract was indispensable besides 2,4-D and kinetin. Such growth-promoting activity was observed also in malt extract and Ebios (dried cell powder of brewery yeast). Of known compounds tested, nicotinic acid, nicotinamide., methyl nicotinate and NAD were promotive to the growth of the callus, although much less effective than yeast extract. Other pyridine derivatives, vitamins and amino acids tested were ineffective or slightly effective. Sucrose was the most suitable carbon source. Fructose, glucose and maltose also supported the growth. Kinetin stimulated cell proliferation of the callus and cell differentiation to tracheary element.     

Volume changes of isolated spinach chloroplasts on illumination in the presence of phenazine methosulfate

Chloroplasts suspended in phosphate buffer with PMS swelledrapidly on illumination, their volumes reaching a maximum levelwithin 5 min. Subsequently they shrank noticeably. Both swellingand subsequent shrinkage were reversible; in the former, chloroplastsswelled on illumination and shrank on turning off the light.In the latter,olume change occurred in the opposite direction.Light-induced swelling in the presence of PMS disappeared onalternating light and dark several times. Thereafter, only shrinkagewas observed. Only shrinkage took place on illumination when PMS was addedto Tris-washed, or heated chloroplasts, or when chloroplastswere suspended in phosphate buffer with other electron transportcofactors such as FMN and vitamin K₃ or in acetate buffer insteadof phosphate in the presence of PMS. PMA and CCCP (low concentration)inhibited swelling with PMS. Quinacrine had no effect on volumechanges with PMS, while antimycin A and CCCP (high concentration)completely prevented both swelling and shrinkage. These suggestthat volume changes are a result of competition between swellingand shrinking activities which depend on utilization of highenergy intermediates formed by PMS-induced photochemical reactions. (Received February 18, 1970; )     

Excitation energy flow at 77 K in the photosynthetic apparatus of overwintering evergreens

The flow of excitation energy from the antennae to photosynthetic reaction centre complexes at 77 K was studied in leaves of two evergreen species, namely, snow gum (Eucalyptus pauciflora Sieb. ex Spreng.) and a hemiparasitic mistletoe (Amyema miquelii, Lehm. ex Miq.). The leaves that were naturally acclimated to winter conditions of freezing temperatures and high irradiance displayed the recently discovered cold‐hard‐band or CHB feature of the chlorophyll a fluorescence spectra (Gilmore & Ball, Proc. Nat. Acad. Sci. USA 97:11098–11101, 2000). A streak‐camera‐spectrograph was used and the double convolution integral method for global analysis was applied to simultaneously acquire and simulate, respectively, the time‐ and wavelength‐dependence of all major chlorophyll a components (Gilmore et al. Phil. Trans. Roy. Soc. B‐London 355:1371–1384, 2000). The CHB coincided with changed amplitudes and decreased excited state lifetimes for the main F685 nm and F695 nm emission bands from the photosystem II (PSII) core‐inner‐antenna. The CHB dissipates energy as heat separate from PSII while also reducing the PSII quantum yield by competing for both photon absorption and antenna excitation. The CHB did not correlate with changes in the decay kinetics of the PSI antenna F740 nm band. The spectral‐kinetic features of the altered energy flow were similar in the unrelated evergreen species. These results are consistent with a functional association between the CHB, PSII energy dissipation and protective storage of chlorophyll in overwintering evergreens.