Band 46, Heft 11-12

The effects of individual or combined treatment of the cyclohexanedione herbicide sethoxydim and the safener dichlormid on total lipid synthesis, protein synthesis and acetyl-CoA carboxylase (ACCase, EC 6.4.1.12) activity of grain sorghum [Sorghum bicolor (L.) M oench, var. G623] were investigated. Sethoxydim and dichlormid were tested at concentrations of 0, 5, 50, and 100 μM each. Sethoxydim applied alone at 50 and 100 μm , inhibited the incorporation of [ 14 C]acetate into total lipids of sorghum leaf protoplasts by more than 50%, following a 4 h incubation. Dichlormid antagonized partially the inhibitory effects of sethoxydim on the incorporation of acetate into total lipids of sorghum protoplasts only when it was used at 100 μM . Sethoxydim applied alone inhibited the incorporation of [ 14 C]leucine into sorghum leaf protoplasts only at 100 μm. Dichlormid was not inhibitory of this process at any concentration. The combined effects of sethoxydim and dichlormid on this process were mainly additive indicating no interactions of the two chemicals. Sethoxydim applied alone at 5 and 50 μM inhibited the activity of ACCase extracted from leaf tissues of grain sorghum seedlings by 58 and 90%, respectively. Addition of the safener dichlormid to the assay medium did not inhibit ACCase activity of sorghum leaves even at the high concentration of 50 μM . The combined effects of sethoxydim and dichlormid on the activity of sorghum ACCase were similar to those observed when sethoxydim was used alone. These results indicate that the protection conferred by dichlormid on grain sorghum against sethoxydim injury can not be explained on the basis of an antagonistic interaction of the two chemicals on target metabolic processes (lipid synthesis) or target enzymes (ACCase).

This study demonstrates that corn can be partially safened by BAS-145138 against sulfonylurea and imidazolinone herbicides. The corn seeds were impregnated with BAS-145138 by soaking the seeds for 6 h in solutions of the safener. BAS-145138 had no effect on corn growth. However, corn shoot and root growth in length, fresh weight, and dry weight was partially protected by BAS-145138 from the phytotoxic effects of the sulfonylurea herbicides thiameturon and CGA -136872. Similar protection was given to corn against the phytotoxic activity of the imidazolinone herbicides imazapyr, imazaquin, and imazethapyr. This study suggests that corn could be safened with BAS-145138 against the phytotoxic effects of residual amounts of sulfonylurea and imidazolinone herbicides found in fields where wheat/corn or soybean/corn rotations take place.

Zea mays L., cv. Potro, shoots had a higher level of resistance to imazaquin (IQ) and metsulfuron methyl (M SM ) than roots. Shoot lengths were increased by pretreating the seeds with commercial 1,8 -naphthalic anhydride (N A ) at 1% (w/w) or oxabetrinil at 0.2% (w/w). The growth of shoots of safened seeds was unaffected by 400 n M IQ and by 40 n M MSM. The in vivo activity of acetolactate synthase (ALS) extracted from corn shoots and roots was not affected by treatments with IQ or MSM, but pretreatment of seeds with NA or oxabetrinil, prior to germination, caused an increase in the level of extractable ALS from shoots. ALS activity from roots and shoots of NA-pretreated seedlings was increased to a large degree (> 40% ) when the seedlings were germinated on 40 nM MSM, whereas ALS activities from oxabetrinil-pretreated seedlings were enhanced to a lesser degree (≈20%). ALS from unsafened seedlings was inhibited 21% by 400 n M IQ and 70% by 40 n M MSM in vitro, but ALS from roots of seedlings germinated on 400 n M IQ was not inhibited by 400 n M IQ in vitro.

Metolachlor and excess Mn 2+ (acid soil stress) induce alterations in gibberellin precursor biosynthesis that can explain the morphological responses to these physiological stresses. Oxabetrinil protects sorghum [Sorghum bicolor (L.) Moench] from the influence of metolachlor and excess Mn 2+ . Sorghum cultivar variations in response to excess Mn 2+ are explicable as differential rates of ent-kaurene biosynthesis between acid soil sensitive and tolerant cultivars. Concentrations of Mn 2+ present in vegetative leaves and reproductive stem tissues were not different. Therefore, cultivar differences in ent-kaurene biosynthesis explain the acid soil tolerance differences rather than differential Mn 2+ absorption, translocation, and/or compartmentation. Metolachlor and safener responses are found in cellular compartments and tissues that do not match a decreased herbicide concentration through absorption, transport, or degradation as a sole mode of action for safeners.

The effect of clopyralid pretreatment (500 g/ha) on picloram-induced ethylene, ACC (1-aminocyclopropane-l-carboxylic acid), and MACC [l-(malonylamino)-cyclopropane-1-carboxylic acid] was measured in rapeseed plants that were treated with 50 or 100 g/ha of picloram. In contrast to plants that did not receive a clopyralid pretreatment, ethylene biosynthesis was significantly reduced in plants pretreated with clopyralid prior to picloram. Picloram- induced levels of ACC also were significantly reduced in plants receiving pretreatment with clopyralid. In contrast, there was no difference between the levels of MACC in plants that were and were not pretreated with clopyralid. Therefore, the mechanism by which clopyralid pretreatment interferes with picloram-induced synthesis of both ACC and ethylene may be manifested through the blocking of de novo synthesis of ACC synthase normally stimulated by picloram. The lack of significant difference in MACC levels between plants that were and were not pretreated with clopyralid precludes the stimulation of enhanced ACC conversion to MACC as an exclusive mechanism of clopyralid’s antidoting activity. It is likely that the rate of picloram-induced ACC synthesis by plants receiving pretreatment is within their capacity to convert ACC to MACC, thereby limiting the substrate available for conversion to ethylene. In contrast, it appears that the extent of ACC synthesis by plants receiving no pretreatment supersedes their capacity for conversion to MACC. thereby resulting in greatly enhanced rates of ethylene evolution and subsequent development of injury symptoms.

Plantago altissima L., Plantago lanceolata L., Plantago atrata Hoppe and Plantago argentea Chaix. were examined for iridoids. In all four species aucubin and catalpol were found. Globularin and methyl ester of the desacetylasperulosidic acid were isolated for the first time from Plantaginaceae plants (P. altissima and P. lanceolata). Asperuloside was found for the first time in P. altissima as well as dihydroaucubin in P. atrata.

Fully substituted quinones including some naturally occurring oxyquinones acted as inhibitors of yeast glutathione reductase (EC 1.6.4.2). They were competitive, mixed or uncompetitive inhibitors for NADPH , possessing K i in the range of 1-200 μM and uncompetitive inhibitors for glutathione. Rhein (4,5-dioxy-9,10-anthraquinone- 2-carbonic acid) and 9,10-phenanthrenequinone were the most effective inhibitors. It is concluded that certain quinones can bind to the NADP(H )-binding site and to the heteroaromatics binding site at the interface domain (P. A. Karplus, E. F. Pai, and G. E. Schulz, Eur. J. Biochem. 178, 693-703 (1989)) of the enzyme.

The complex biological phenomenon “resistance” can be reduced to single Mendelian traits acting on both the plant and the pathogen side in a number of pathosystems. According to the “gene-for-gene hypothesis”, the outcome of a plant/pathogen interaction in these cases is incompatibility if a plant carrying a particular resistance gene and a pathogen with the complementary avirulence gene meet. This suggests a causal role of resistance genes in a recognition process initiating active plant defense responses. Fundamentally different strategies are followed to identify these genes molecularly depending on the plant and pathogen species involved. Fungal diseases of crop plants, especially those of cereals, cause dramatic yield losses worldwide. It is assumed that a molecular characterization of plant genes conferring resistance to fungal pathogens will lead to a better understanding of the plant defense system in general permitting the development of new methods of crop plant protection.

In a systematic study the organic carbon content of typical Germ an soils was studied by solid state C-13 CPM AS spectroscopy. In order to check the quantitative validity of the standard sodium hydroxide extraction procedure, which fractionates soil organic matter into hum in, humic acid, and fulvic acid also the high resolution solid state spectra of these fractions were determined. The chemical information obtained from these spectra is discussed.

Omphalone, a new antibiotic, cytotoxic, and phytotoxic pigment has been isolated from fermentations of a Canadian strain of Lentinellus omphalodes. Its structure has been established as 2-(4-methylfuran-2-yl)-l,4-benzoquinone (1) by spectroscopic investigations and conversion into leuco-acetate 2.

The isolation of the common chromophore of the pyoverdins isolated from iron-deficient cultures of fluorescent Pseudomonas strains and of its 5-hydroxy analogue as well as the spectroscopic characterization of the two compounds is described.

The new iridoid 10-acetylaucubin and the well known iridoids aucubin. melittoside and monomelittoside as well as the rare 6-epiaucubin and 3,4-dihydroaucubin were isolated from aerial parts of Plantago carinata Schrad. This is the first isolation of 6-epiaucubin from Planta-ginaceae plants and of 3,4-dihydroaucubin and monomelittoside from P. carinata Schrad.

From the young leaves of Euonymus alatus f. ciliato-dentatus, a novel enzyme, UDP-D-xylose: flavonol 3-O-xylosyltransferase (F3XT), catalyzing the transfer of D-xylose from UDP-D-xylose to the 3 position of 3,5,7,4′-tetrahydroxyflavone (kaempferol), was detected and purified about 16-fold by precipitation with ammonium sulfate and DEAE-cellulose CC, by which F3XT was separated from two coexisting flavonol O-glucosyltransferases (FGT). Thus, F3XT was isolated as a soluble enzyme with a pH optimum of 7.0 in Tris-HCl buffer. The molecular weight of F3XT , which had an isoelectric point at pH 6.1, was estimated by elution from a column of Sephadex G-100 to be about 48 kDa. The activity of F3XT was stimulated by 14 mM 2-ME and strongly inhibited by 1 m Abstractм Cu 2+ , 1 m м Zn 2+ , and various re­ agents that react with sulfhydryl groups. Among the substrates tested for F3XT , kaempferol was the best. The K m values for kaempferol and UDP-xylose were determined to be 0.83 jim and 25 μ M, respectively. F3XT mediated the transfer of xylose exclusively to the 3-hydroxyl group of kaempferol. Isorhamnetin, quercetin and fisetin also can function as xylosyl acceptor though less efficiently, but neither the 7-O-glucosides nor the 3-O-glucosides of kaempferol and quercetin were able to accept D-xylose. Dihydroflavonols were not xylosylated.

Effect of manganese with three different valence states on carthamin formation was studied by using freshly collected flowers from dyer’s saffron (C. tinctorius) capitula. At 1-10 hm concentration, these cations accelerated markedly the carthamin formation induced by endoge­ nous enzyme(s) in the detached floral tissues. The acceleration was obviously dependent on the valence state of the test metals, more pronounced by Mn(VII) or Mn(III) than by Mn(II) at a series of given ionic strengths. On a 1 μм level, Mn(VII) and Mn(III) accelerated the pigment accumulation by faster of 9 and 8, resp. than Mn(II) during 5 min incubation at 30 °C. Mn(VII) and Mn(III) acted on both fresh and boiled florets, while Mn(II) exerted preferentially its activity on intact materials. Possible im plication of manganese ions on the enzyme-cata-lyzed carthamin formation are discussed.

Porphobilinogen-deaminase from Saccharomyces cerevisiae has been isolated and partially purified 80-and 230-fold in the absence or presence of phenylmethylsulphonyl fluoride, respectively. Some properties of the isolated enzyme were studied. Porphyrin formation was linear with time and protein concentration. Optimum pH was about 7.5-7.8. Molecular mass of the protein was 30,000 ± 3000 Dalton when the enzyme was purified in the presence of phenylmethyl­ sulphonyl fluoride. A less active and unstable 20,000 Da molecular mass species was obtained when purification was performed in the absence of the protease inhibitor. Porphobilinogen-deaminase exhibited classical Michaelis-Menten kinetics. The apparent K m for uroporphyrinogen formation was 19 μм; V max was 3.6 nmol uroporphyrin/h and the Hill coefficient was n = 1. Also the action of several reagents on the activity was studied. Protective thiol agents had no effect. Heavy metals inhibited both porphyrin formation and porphobilinogen consumption, but known sulphydryl inactivating chemicals inhibit the former without modifying the latter. Ammonium ions had no effect on the activity while hydroxylamine completely inhibited both porphyrin formation and porphobilinogen consumption.

An investigation about the in vivo inactivation of photosynthetic water oxidation has been carried out in the cyanobacterium Anacystis nidulans (Synechococcus PCC 6301). Photosystem II and photosystem I activity as well as the relative amount of the D1 and manganese stabilizing peptide of photosystem II were determined after growing the cells in nutrient media with variations in the nitrogen source and the concentration of the major divalent cations (Mg 2+ and Ca 2+ ). The results show a rapid inactivation of water oxidation in A. nidulans in response to nitrogen deficiency and in response to reduced Mg 2+ and Ca 2+ concentrations. The inactivation of water oxidation observed under divalent cation deficiency could be greatly accelerated when L-amino acids instead of ammonia or nitrate were used as nitrogen source. Under these conditions inactivation of water oxidation correlated with a rapid loss of D1 and with a slower loss of the manganese stabilizing peptide from photosystem II. A possible regulation of the photosystem II activity in A. nidulans by nitrogen metabolites is suggested.

Flash induced oxygen evolution patterns of isolated PS II complexes from the cyanobacterium Synechococcus were measured with a Joliot-type electrode. By suitable preflash and dark adaptation procedures, samples were prepared in the state S 1 (100%), as well as enriched in S 0 (60% S0, 40% S,). After treatment with low concentrations of NH 2 OH (≤ 100 μм), the two flash patterns were identical. This is further evidence for a reduction of the water oxidizing complex by hydroxylamine in the dark. Two reduced states (S -1 and S -2 ) below S 0 are formed by this reduction.

Preillumination of intact pea leaves with a strong blue-green light of 400 W m -2 markedly inhibited both photoacoustically monitored O 2 -evolution activity and PS II photochemistry as estimated from chlorophyll fluorescence measurements. The aim of the present work was to examine, with the help of the photoacoustic technique, whether this high-light treatment deteriorated the in vivo PS I function too. High-frequency photoacoustic measurements indicated that photochemical conversion of far-red light energy in PS I was preserved (and even transiently stimulated) whereas photochemical energy storage monitored in light exciting both PS I and PS II was markedly diminished. Low-frequency photoacoustic measurements of the Emerson enhancement showed a spectacular change in the PS II/PS I activity balance in favor of PS I. It was also observed that the linear portion of the saturation curve of the far-red light effect in the Emerson enhancement was not changed by the light treatment. Those results lead to the conclusion that, in contrast to PS II, the in vivo PS I photofunctioning was resistant to strong light stress, thus confirming previous suggestions derived from in vitro studies. Estimation of the redox state of the PS I reaction center by leaf absorbance measurements at ca. 820 nm suggested that, under steady illumination, a considerably larger fraction of PS I centers were in the closed state in high-light pretreated leaves as compared to control leaves, presumably allowing passive adjustment of the macroscopic quantum yield of PS I photochemis­ try to the strongly reduced photochemical efficiency of photoinhibited PS II.

Three different phytoene desaturase genes, from Rhodobacter capsulatus, Erwinia uredovora, and Synechococcus PCC 7942, have been functionally complemented with a gene construct from E. uredovora which encodes all enzymes responsible for formation of 15-cis phytoene in Escherichia coli. As indicated by the contrasting reaction products detected in the pigmented E. coli cells after co-transformation, a wide functional diversity of these three different types of phytoene desaturases can be concluded. The carotenes formed by the phytoene desaturase from R. capsulatus were trans-neurosporene with three additional double bonds and two cis isomers. Furthermore, small amounts of three ζ-carotene isomers (2 double bonds more than phytoene) and phytofluene (15-cis and all-trans with + 1 double bond) were detected as inter- mediates. When the subsequent genes from E. uredovora which encode for lycopene cyclase and β-carotene hydroxylase were present, neurosporene, the phytoene desaturase product of R. capsulatus, was subsequently converted to the monocyclic β-zeacarotene and its mono- hydroxylation product. The most abundant carotene resulting from phytoene desaturation by the E. uredovora enzyme was trans-lycopene together with a cis isomer. In addition, bisdehy-drolycopene was also formed. The reaction products of Synechococcus phytoene desaturase were two cis isomers of ζ-carotene and only small amounts of trans-ζ-carotene including 15-cis. The I 50 values for flurtamone and diphenylamine to inhibit phytoene desaturation were determined and differential inhibition was observed for diphenylamine.

Accumulation of protochlorophyllide (Pchlide) was determined after incubation of etiolated seedlings of garden cress (Lcpidium sativum L.) with exogenous 5-aminolevulinate for 24 h. Young seedlings (start of incubation 0-12 h after imbibition) accumulated only moderate amounts (<0.2 nmol per seedling) of Pchlide. Maximum capacity of Pchlide accumulation (ca. 14 nmol per seedling) was reached at 30-36 h after imbibition. At 60-72 h after imbibition, the capacity of Pchlide formation from exogenous ALA was only 0.2-0.3 nmol per seedling. Uptake of ALA via roots was high in young and old seedlings. The carotenoid content and pattern did not change by ALA incubation. Precursors of Pchlide were also accumulated by ALA treatment. Predominant products were protoporphyrin and magnesium protoporphyrin (MgP) in 30 h old seedlings but magnesium protoporphyrin monomethylester (MgPMe) in 72 h old seedlings. The previously described interaction of Pchlide precursors with cab gene expression cannot be correlated with a single porphyrin. A possible correlation with the ratio MgPMe: MgP is discussed.

Thiazolylidene-ketonitriles are efficient inhibitors of photosynthetic electron flow in reaction centers from either Rhodobacter sphaeroides or Rhodobacter capsulatus. Some compounds of this class exhibit a higher inhibitory potency in the bacterial system as compared to photosystem II. Up to now, photosystem II inhibitors were generally less active in photosynthetic bacteria. An azido-thiazolylidene-ketonitrile upon illumination almost exclusively tags the L-subunit in the bacterial reaction center.

The content of ColE 1-related plasmids increased about 4-6-fold after a temperature-shift from 30 to 42 °C (45 °C) if the rom-region of the plasmids was deleted. The copy number of rom + -plasmids did not change after the temperature shift. All rom¯-plasmids tested in this study showed this plasmid amplification. The Rom-protein is capable of inhibiting plasmid replication by stabilization the initial reversible stage of the association of RNAI with the primer precursor RNAII. We suggest that the temperature-dependent enhancement of the copy number of rom¯-plasmids is due to a destabilization of this initial phase of the RNAI-preprimer interaction at high temperatures which is suppressed by the Rom-protein in cells with rom + -plasmids.

The sedative properties of the essential oil of Lavender (Lavandula angustifolia Miller) and of its main constituents - linalool and linalyl acetate - were investigated in mice followed up in a series of experimental procedures. The significant decrease in the motility of female and male laboratory animals under standardized experimental conditions is found to be closely dependent on the exposure time to the drugs. Nevertheless after an injection of caffeine into mice a hyperactivity was observed which was reduced to nearly a normal motility only by inhalation of these fragrance drugs. In particular the correlation of the motility of the animals to linalool in serum is experimentally proven, thus furnishing evidence of the aromatherapeutical use of herbal pillows employed in folk medicine since ancient times in order to facilitate falling asleep or to minimize stressful situations of man.

Following the observation that the non-ball-rolling dung beetle Pachylomerus femoralis (Kirby) rolled the flesh-covered seeds from the fruit of the spineless monkey orange tree, Strychnos madagascariensis Poiret, an investigation into the chemical attractants of this fruit was made. Using headspace gas chromatography with electroantennographic and flame ionization detection in parallel, followed by GC-MS analysis, 1-butanol, methyl butanoate, ethyl 2-methylpropanoate, ethyl butanoate, butyl ethanoate, ethyl 2-methylbutanoate, propyl butanoate, butyl propanoate, methyl hexanoate, butyl 2-methylpropanoate, and butyl butanoate were identified as the constituents of the attractant. It was found that P. femoralis beetles were attracted to a mixture of the synthetic compounds about as strongly as to the fresh fruit. The beetles were also equally attracted to the fruit and to horse dung in areas where ripe fruit was not available. In areas permeated with the smell of the ripe fruit the horse dung retained its attractiveness, whereas no beetles were caught in traps baited with fruit.

Larvae of Uresiphita reversalis feed almost exclusively on legumes of the tribe Genisteae, whose characteristic secondary metabolites are quinolizidine alkaloids (QA). Aposematic larvae store host plant-derived QA in their integument, while the pupae are almost alkaloid-free. In the last instar larvae, alkaloids were concentrated in the larval head, possibly in the silk glands. About 80% of the alkaloids were transferred to the cocoon silk and 19% were lost with larval exuviae. The larval alkaloid pattern was characterized by capillary GLC and GLC-MS and compared to that of the host plant, Teline monspessulana. Whereas the host plant contained mainly epiaphylline, dehydroaphylline and aphylline, larvae selectively accumulated N-methylcytisine, a relatively minor component of the plant QA; the faeces contained mainly epiaphylline and dehydroaphylline. Thus uptake and sequestration must be selective processes. Uptake by isolated larval midguts was time-, pH- and temperature-dependent and displayed an activation energy between 50 and 80 kJ/mol. Furthermore the in vitro uptake of 13-hydroxylupanine was competitively inhibited by cytisine. All these data provide evidence that QA uptake does not proceed by simple diffusion but instead with the aid of a carrier mechanism; this could explain the differential alkaloid uptake observed in living larvae.

Acetylcholinesterase (AchE) can be induced in a non-neuronal, epithelial cell line from Chironomus tentans by the moulting hormone 20-OH-ecdysone. Maximal response is reached after 7 days. The increase in enzymatic activity can be suppressed by simultaneous incubation with inhibitors of transcription and translation. The potency of various steroid hormones to induce AchE coincides with their affinity to the ecdysteroid hormone receptor. AchE from Chironomus is tightly bound to membranes and cannot be solubilized by heparin or collagenase treatment. Incubation under conditions where phospholipase C is most active releases activity into the supernatant. If phospholipase is applied in addition, the amount of solubilized enzyme increases, but there is still membrane-bound activity left. This is in accordance with a globular form of AchE linked to membranes by a phospholipid-anchor. The enzyme sediments as a single peak of 5.4 S.

Exposure of embryos of the sea squirt, Ciona intestinalis, to all-trans-retinoic acid (between 10 -5 and 10 -7 m) causes specific malformations of the larvae and suppression of settlement and metamorphosis. Whether the vitamin A derivative was administered at the 2-cell stage, or at the early gastrula stage did not affect the nature or the extent of the ensuing anomalies. Malformations include a dorsal bulge of the body, an irregular disposition of ocellar pigment, and a twisted tail. Treated larvae have no statocyst pigment. There is also a reduction in size of the body, compared to control larvae. Retinoic acid retarded hatching, or even blocked it (at 10 -5 m). Obviously retinoic acid interferes with the induction of metamorphosis, possibly through neutralizing one or more factor|s responsible for settlement and metamorphosis. The possible role of thyroxin in these processes is being critically evaluated.

Porphobilinogen-deaminase (PBG-D) and PBG-D-isomerase complex (PBG-D-I) from pig liver were isolated and partially purified. Uroporphyrinogen I and III formation was found to be linear with time and protein concentration. Optimal pH was about 7.4 and 7.6-7.8 for PBG-D and PBG-D-I complex, respectively. Some properties of the isolated enzymes were studied. Molecular mass determination gave a value of 40,000 Da for PBG-D and 50,000 Da for the complex. Both enzymes exhibited classical Michaelis-Menten kinetics. K m and F max parameters were estimated. The effect of several divalent cations, ammonia and thiol reagents was also investigated. The differential action of some of these chemicals on PBG-D and PBG-D-I system would suggest that PBG-D and isomerase may not be only physically adjacent but actually associated.

Calcium transport of skeletal muscle sarcoplasmic reticulum was comparatively studied in hibernating and summer active European hamsters (Cricetus cricetus L.). Crude homogenates from psoas, soleus and mixed skeletal muscles were used. Protein yield was strongly reduced in the muscle homogenates of hibernating hamsters. The calcium concentration in the muscle of hibernating hamsters was increased to a much higher content than in the serum. In the same animals the maximal rate of calcium uptake and the calcium storing capacity of sarcoplasmic reticulum were augmented by 43% and respectively 17%. Kinetic experiments with various concentrations of free calcium revealed in the hibernating animals higher uptake rates and a lower apparent calcium affinity than in the summer active hamsters. Some shift of calcium uptake rate and calcium affinity similar to that of a fast-twitch muscle was also observed in winter active animals kept at 22 C under natural photoperiod. By contrast, the activity of the calcium dependent ATPase was not increased, suggesting a tighter coupling during hibernation between calcium dependent ATP-hydrolysis and calcium transport. No seasonal difference was observed in the calcium release by KCl-caffeine from calcium loaded vesicles of sarcoplasmic reticulum. Proportion and size of fibre types were studied with cold cross sections from psoas and soleus muscles. An average atrophy of about 25% was found during hibernation in both muscles. Cytochemistry revealed, however, a different reduction of cross area between type-I- and type-11-fibres, which reaches values up to 46% in the type-I I-fast-fibres of the slow soleus muscle. Electron microscopy did not show any definite change in the distribution and amount of sarcoplasmic reticulum. The results suggest that during hibernation a modulation in the properties of calcium transport ATPase of sarcoplasmic reticulum occurs to better support the calcium transport function at low temperatures, which in turn warrants the restoration of ion homeostasis in the course of the arousal.

The growth regulators (-)-jasmonic acid (JA) and its 7-isom er were identified by GC-MS in the red alga Gelidium latifolium. The ratio of JA:7-iso-JA was approximately 93:7. The endogenous level amounted to 0.7 μg JA/g fresh weight.

Enumeration of Viable Cells, FACS, Fluorescent Micro- spheres, Rat Brain Cells We describe a flow cytometric method for the quantitation of small numbers of cells that facilitates proliferation studies in microcultures. A constant number of fluorescent latex microspheres/sample is added to single cell suspensions prepared from the cultures. By flow cytometric analysis, cells are easily distinguishable from the microspheres and can be quantitated on the basis of their light scattering and fluorescence properties in contour plots. As the number of microspheres/sample is known, the relative proportions of cells and microspheres, respectively, can be converted into absolute cell numbers. This quick method is useful for any type of studies where cell numbers < 1 x 10 5 in a small volume are to be determined.

Among the electrical signals that can be recorded from the vertebrate cortex are voltage oscillations in the frequency range 40-70 Hz (γ-waves). For some years the possible role of these waves as information carriers has been under discussion. Relatively high-level functions such as “feature linking” have been proposed for them, and they have even been considered in the context of phenomena such as “awareness” and “consciousness” [1]. The insect brain exhibits high-frequency (hf) oscillations in the range of 100-200 Hz that have much in common with the γ-waves, but their function is interpreted differently.