A new record ofAchlya klebsiana from snakehead,Channa striatus,with fungal infection in Myanmar

This is the first record of the discovery in Myanmar ofAchlya klebsiana, belonging to the family Saprolegniaceae.     

Conditions of the primary culture for rat hepatocytes and plasminogen activator release

The conditions of primary culture for rat hepatocytes was investigated on the releasing effect of Plasminogen Activator (PA). The culture method using Collagen Coated Dish (CCD-method) which is currently available and the ordinary culture method using Plastic Culture Dish (PCD-method) were employed for that purpose in a comparative way. The effect of the addition of some supplements, that is FN, Aprotinin, EGF were also investigated. The following results were obtained. The dissociated rat hepatocytes formed a monolayer with pavementlike morphology at 24-48 hours after seeding. No difference was observed in the morphology of hepatocytes during the culture period between the two methods, although CCD-method allowed 120 hours culture, whereas PCD-method allowed 72 hours. The PA activity was demonstrated on the hepatocytes by either culture method according to the fibrinolysis autography. The cultured hepatocytes released PA into the medium continuously as long as the viability and morphology of the cells were maintained in good state. The PA activity reached the maximum after 96 hours culture in CCD-method, whereas it reached the maximum after 48 hours in PCD-method. The addition of Aprotinin to the culture medium was not necessary for PA release in CCD-method in contrast to PCD-method. When EGF was discontinued in the culture medium, the release of PA was reduced in association with the occurring of morphological disintegration of hepatocytes.     

Calcium and ATP regulation of the oscillatory torsional movement in a Triton model of Physarum plasmodial strands

A segment of the plasmodial strand of Physarum polycephalum, when hung vertically, shows oscillatory torsional movements that accompany shortening and elongation, i.e., contraction and relaxation in the vertical direction. Reactivation of such movements was achieved in a fresh, demembranated model system through the use of Triton X-100 and chemically defined physiological solutions. Oscillatory rotations were reactivated in solutions containing 0.5 mM Mg-ATP and 10⁻⁶–10⁻⁴ of free Ca²⁺. Lowering the Ca²⁺ concentration to 10⁻⁸ M brought about unidirectional rotations with concomitant vertical elongation of the strands, i.e., relaxation. Such unidirectional rotations were also observed either when Mg-ATP concentrations was raised to 5 mM, or when Mg-ATP was replaced with Mg-pyrophosphate. Higher concentrations of free Ca²⁺ than 10⁻⁴ M similarly caused unidirectional rotations, but there was no concomitant vertical elongation. These data mean that the oscillatory contraction and relaxation require a factor which is activated at Ca²⁺ concentration above 10⁻⁶ M and inactivated at 10⁻⁸ M. The findings that Mg-pyrophosphate or high concentrations of Mg-ATP-induced relaxation suggest that the actomyosin is dissociated in the relaxation phase. In the light of the present study, it is not likely that the periodic movement in the plasmodia is caused by any oscillatory activities in either the ATP-producing system or the plasma membrane.     

Promotion of auxin- and gibberellin-induced elongation of epicotyl segments of Vigna angularis by short-chain carboxylic acids

Journal of Plant Research - Pollen tube growth is inhibited and promoted by long- and short-chain carboxylic acids, respectively, but is not affected by formic acid. For auxin- and...     

Enzyme immunoassay of serum testosterone.

An enzyme immunoassay of serum testosterone using the testosterone-glucoamylase complex is described. Testosterone was estimated by the enzyme immunoassay after extraction with hexan: ether (4:1) for serum from men and additional thin layer chromatographic step for serum from women. The within and between assay errors, measured as the coefficient of variation were 11.1 percent (n=8) and 12.0 percent (n=12). The sensitivity of this assay was 0.25 ng. The mean testosterone concentration (+/- SD) in 19 normal men and 4 normal cycling women were 5.3 +/- 1.8 and 0.52 +/- 0.12 ng/ml, respectively. The level of testosterone found by the present assay compared favorably with those obtained by other methods.     

Absence of arabinan in the side chains of the pectic polysaccharides strongly associated with cell walls of Nicotiana plumbaginifolia non-organogenic callus with loosely attached constituent cells

When leaf disks from haploid plants of Nicotiana plumbaginifolia Viv. were transformed with T-DNA and cultured on shoot-inducing medium, nonorganogenic callus. designated nolac (for non-organogenic callus with loosely attached cells), appeared on approximately 7% of leaf disks. In contrast, normal callus was generated on T-DNA-transformed leaf disks from diploid plants and on non-transformed leaf disks from haploid and diploid plants. Transmission electron microscopy revealed that the middle lamellae and the cell walls of one line of mutant callus (nolac-H14) were barely stained by ruthenium red. even after demethylesterification with NaOH, whereas the entire cell wall and the middle lamella were strongly stained in normal callus. In cultures of nolac-H14 callus, the level of sugar components of pectic polysaccharides in the hemicellulose fraction was reduced and that in the culture medium was elevated, as compared with cultures of normal callus. These results indicate that pectic polysaccharides are not retained in the cell walls and middle lamellae of nolac-H14 callus. In nolac-H14, the ratio of arabinose to galactose was low in the pectic polysaccharides purified from all cell wall fractions and from the medium, in particular, in the hemicellulose fractions. The low levels of arabinofuranosyl (T-Araf, 5-Araf, 2,5-Araf, and 3,5-Araf) residues in the pectic polysaccharides of the hemicellulosic fraction of nolac-H,14 indicated that no neutral-sugar side chains, composed mainly of linear arabinan. were present in nolac-H14. Arabinose-rich pectins. which are strongly associated with cellulose-hemicellulose complexes, might play an important role in intercellular attachment in the architecture of the cell wall.