Production of transgenic rats using cryopreserved pronuclear‐stage zygotes

We investigated the application of cryopreserved pronuclearstage zygotes for the production of transgenic rats. Most of the pronuclearstage zygotes cryopreserved by conventional twostep freezing or vitrification appeared morphologically normal, but the proportion of frozen zygotes that developed into fetuses following transfer (59.7–60.2%) was higher than that of vitrified zygotes (5.5–22.1%). When the frozenthawed zygotes were used for DNA microinjection, 97.5% survived after DNA microinjection and 25.1% of the transferred zygotes developed into fetuses. These proportions were comparable to those of the fresh control zygotes (97.0% and 30.0%, respectively). The integration efficiency of the exogenous DNA into fetuses was similar between the frozen group (3.3% per injected zygote) and the control group (3.5%). These results indicate that pronuclearstage rat zygotes can be successfully cryopreserved by conventional twostep freezing for production of transgenic rats.     

Untersuchungen zur Kompartimentierung der freien Aminosäure Alanin in den Farnvorkeimen von Dryopteris filix-mas (L.) Schott im Rotlicht und im Blaulicht

Summary In fern gametophytes (= sporelings) there is a strong correlation between the degree of blue light mediated photomorphogenesis and the protein content of the organism (cf. Mohr, 1963). In a previous paper (Payer et al., 1969) we have shown that blue light specifically increases the rate of protein synthesis in the fern sporelings over the rate which is maintained under red light. — In the present paper blue light mediated protein synthesis has been dealt with further using one representative amino acid, alanine, which was labelled with ¹⁴C from ¹⁴CO₂ under steady state conditions of photosynthetic ¹⁴C incorporation under blue or red light.Synthesis of free alanine is proportional to the rate of photosynthesis (Table 1). For a number of reasons we conclude that alanine is derived directly from primary photosynthetic products. Since the pool size of the thoroughly ¹⁴C-labelled pool of free alanine is much less than the actual, pool size of this amino acid, (Table 1), and since the specific activity of the isolated ¹⁴C-alanine is much below the value we can expect on the basis of the specific activity of the ¹⁴CO₂ applied we conclude that there are separate pools of free alanine; active (with respect to protein synthesis) and inactive pools which do not mingle. Taking into account this possibility of compartmentation of pools of free amino acids we have calculated in the case of ¹⁴C-alanine the rate of protein synthesis for two extreme instances (Table 2). A comparison of the theoretical values with the actual data indicates that indeed protein synthesis is fed from active pools of amino acids while the inactive pools are possibly located in the vacuoles. The total pool of alanine is much larger in red grown than in blue grown sporelings while the active pools seem to have the same size under both conditions. The cells of the red grown sporelings have much larger vacuoles than the cells of the blue grown sporelings.The rate of protein synthesis is under our conditions 1.8 times higher in blue light than in red light. The rate of turnover of the total protein is 0.29% per hour in the blue and 0.23% in the red light. The absolute turnover of protein is 1.5 times higher in blue light than in red light. It is concluded that the blue light mediated increase of protein synthesis is very real. Blue light must act specifically at the level of polypeptide synthesis.     

Grazing by a dominant rotifer Conochilus unicornis Rousselet in a mountain lake: in situ measurements with synthetic microspheres

Grazing rates of zooplankton were analysed in the summer of 1999 in Yellow Belly Lake, an oligotrophic system in the Sawtooth Mountains of Idaho (U.S.A.). The colonial rotifer Conochilus unicornis was a dominant species in the epilimnion, with densities reaching 20 colonies l^–1 (ca. 400 ind. l^–1). Clearance rates were measured with an in situ Haney Grazing chamber and synthetic microspheres 5, 9 and 23m in diameter. At epilimnetic temperatures of around 14 °C, mean clearance rates for 5m particles ranged from 30 to 65 l ind.^–1 h ^–1. Clearance rates were 2–9 times higher on the 5m spheres than on the 9 m spheres, and C. unicornis almost never fed on the 23 m spheres. Grazing rates did not change over the diel cycle. Clearance rates declined more than 10-fold as temperatures declined from 14 °C in the epilimnion to 7 °C in the metalimnion. In the epilimnion, grazing by C. unicornis was more important than grazing by crustaceans in the community, at least on particles 9m. The results show the importance of grazing by rotifers in lakes, and the significance of spatial variations that influence grazing rates.     

Experimental data on the inheritance of some taxonomic characters inHordeum spontaneum C. Koch emend. Bacht

Summary Hordeum spontaneum C. Koch emend. Bacht. varieties have been both intercrossed and crossed with two cultivated barley varieties ofH. vulgare (L.) emend Vav. et Bacht. with a view of eliciting the nature of inheriting the spikelet-pedicel of the lateral spikelets and the shape of their apex in the said wildgrowing barley. The investigations of F₁ and F₂ showed the inheritance of the spikelet-pedicel to have a dominating nature and to segregate in F₂ in conformity with the Mendelian monohybrid type. In the second case the forms with shorter awn-like formations, or their rudiments, were dominating.As a result ofH. spontaneum x H. vulgare hybridization along with already known forms, new formations were received, they have been conditionally named by the author:sessiliproskowetzii, proskowfertillum, ischnofertillum, and pallipodum.

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Zusammenfassung Im Rahmen größerer Untersuchungen über die Abstammung und Phylogenie der Gerste wurden mehrere Varietäten vonHordeum spontaneum C. Koch emend. Bacht. sowohl untereinander als auch mit zwei Varietäten der Kulturgerste,H. vulgare (L.) emend. Vav. et Bacht., gekreuzt. Es sollte geklärt werden, wie bei den genannten Wildgersten das Stielchen (pedicel) der Seitenährchen sowie die Ausbildung des Apex der Seitenährchen (d. h. ihre Begrannung) vererbt werden. Die Untersuchung der F₁ und F₂ zeigte, daß das Stielchen (gegenüber ungestielten Seitenährchen) dominant und gemäß einer monohybriden Mendelspaltung vererbt wird. Bezüglich der Ausbildung des Apex der Seitenährchen ergab sich im allgemeinen Dominanz der kürzeren oder rudimentären Grannen gegenüber längeren Grannen.Im Ergebnis der Hybridisation zwischenH. spontaneum undH. vulgare wurden, neben bereits bekannten, verschiedene neue Formen gefunden, die vom Autor vorläufig wie folgt benannt werden:sessiliproskowetzii, proskowfertillum, ischnofertillum, pallipodum.Die Ergebnisse werden im Zusammenhang mit Fragen der Abstammung der Kulturgerste diskutiert.

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With 4 figures     

Effect of cerulenin on the production of mannosyl-erythritol lipids as biosurfactants by Candida antarctica

Summary The effect of cerulenin, anti-lipogenic antibiotic, on the production and fatty-acid profiles of biosurfactants (mannosyl-erythritol lipids) of Candida antarctica were investigated by changing the chain-length of fatty acid as the carbon source. On longer-chain acid (C₁₄ to C₁₈), the production and fatty-acid profiles of the biosurfactants were not entirely affected by the antibiotic, indicating that the yeast is able to synthesize the biosurfactants from those substrates without the operation of de novo synthesis system of fatty acid. These results thus confirm our previous presumption that a new type of chain-shortening system (partial -oxidation system) mainly contributes to the formation of the extracellular glycolipids as biosurfactants.     

Formation of protoplasts from Ustilago maydis

Protoplasts of Ustilago maydis were obtained by incubating sporidia of the fungus with a combination of Helicase and a commercial Onozuka R-10 enzyme preparation of Trichoderma harzianum in the presence of 0.6 m (NH₄)₂ SO₄ as an osmotic stabilizer. In the presence of the organic stabilizers sorbitol and sucrose, however, the release of protoplasts was inhibited. Combinations of Helicase with other lytic enzymes such as cellulase from Aspergillus niger, cellulase and hemicellulase from Rhizopus, and Driselase or Nagarse were inactive.     

Purification and characterization of flavone-specific β-glucuronidase from callus cultures of Scutellaria baicalensis Georgi

-Glucuronidase from callus cultures of Scutellaria baicalensis Georgi was purified to apparent homogeneity by fractionated ammonium-sulfate precipitation and chromatography on diethylaminoethyl-cellulose, hydroxylapatite and baicalin-conjugated Sepharose 6B. A 650-fold purification was obtained by this purification system. When subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis the purified protein migrated as a single band with a molecular mass of 55 kDa. We determined that the native enzyme has a molecular mass of 230 kDa using gel-filtration chromatography. These results suggested that the enzyme exists as a homotetramer composed of four identical 55-kDa subunits. The enzyme showed a broad pH optimum between 7.0 and 8.0. The K _m values were 9 M, 10 M, 30 M and 40 M for luteolin 3 -O--d-glucuronide, baicalin, wogonin 7-O--d-glucoronide and oroxlin 7-O--d-glucuronide, respectively. The enzyme was most active with flavone 7-O--d-glucuronides.Abbreviations BA N⁶-benzyladenine - 2,4-D 2,4-dichlorophenoxyacetic acid - pI isoelectric point - R _t retention time     

Experimentally elevated testosterone increases status signalling in male Greylag geese (<Emphasis Type="Italic">Anser anser</Emphasis>)

Testosterone modulates male vertebrates sexual and social behaviour. We experimentally investigated the testosterone-sensitive behaviours in male greylag geese (Anser anser) by implanting silastic tubes containing crystalline testosterone during the mating season (February; 5 implanted and 5 control males) and in the early winter (November; 7 and 7). Focal animals were part of a semi-tame, unrestrained flock with fully intact social relationships. Excreted testosterone and corticosterone immunoreactive metabolites (TM, BM) were determined by enzyme immunoassay. Individual faecal samples and behavioural protocols were collected daily over a period of 5 weeks, including 1 control week before implantation. In February, no significant behavioural effects of the supplemental testosterone were observed, which may be due to the naturally occurring high systemic androgen levels in spring. In November, however, implanted males had higher TM excretion rates and performed status signalling behaviour (beak up) more frequently than control males. No differences between implanted and control males were found with respect to BM, agonistic interactions or vigilance behaviour. Furthermore, during the second week after implantation, TM positively correlated with the frequency of beak up of implanted males, whilst their female partners were attacked with lower latency by other members of the flock than the females of control males. Hence, status signalling in greylag ganders seems to be testosterone-sensitive year-long and inappropriate status signalling of males may draw attacks towards their females.     

Production of β-fructofuranosidase byAspergillus japonicus

A newly isolated strain, MU-2, which produces very high -fructofuranosidase activity, was identified asAspergillus japonicus. For enzyme production by the strain, sucrose at 20% (w/v) was the best carbon source and yeast extract at 1.5 to 3% (w/v) the best nitrogen source. Total enzymatic activity and cell growth were at maximum after 48 h, at 1.57×10⁴ U/flask and 0.81 g dry cells/flask, respectively. The optimum pH value of the enzymatic reaction was between 5.0 and 5.5 and the optimum temperature 60 to 65°C. The enzyme produced 1-kestose (O--d-fructofuranosyl-(21)--d-fructofuranosyl -d-glucopyranoside) and nystose (O--d-fructofuranosyl-(21)--d-fructofuranosyl-(21)--d-fructofuranosyl -d-glucopyranoside) from sucrose by fructosyl-transferring activity. The strain was found to be very useful for industrial production of -fructofuranosidase.     

The effect of the Fusarium metabolite beauvericin on electromechanical and -physiological properties in isolated smooth and heart muscle preparations of guinea pigs

The electromechanical and -physiological effects of beauvericin were studied in isolated smooth and heart muscle preparations of the guinea pig. Beauvericin concentration-dependently decreased the force of contraction in precontracted (60 mM KCl) terminal ilea with an IC₅₀ of 0.86 M, and in electrically stimulated (1 Hz) papillary muscles with an IC₅₀ of 18 M. This negative inotropic effect in papillary muscles was antagonised in a non-competitive way by increased extracellular calcium concentrations. Spontaneous activity in right atria was affected at concentrations >10 M beauvericin. The negative chronotropic effect was less pronounced than the negative inotropic effect. In action potentials of electrically driven (1 Hz) papillary muscles, 10 M beauvericin significantly decreased membrane resting potential until unexcitability of the preparation occurred. Despite depolarisation of the membrane the maximum rate of rise of the action potential was not changed. The action potential duration was shortened, but the decrease was only significant at times to 20% and 50% repolarisation. These data, derived from the electrophysiological experiments, not only imply an effect on the calcium current as suggested by the effects on contractility, but also an interaction with the sodium inward and potassium outward currents.This revised version was published online in October 2005 with corrections to the Cover Date.     

Molecular cloning of phenylalanine ammonia-lyase cDNA and classification of varieties and cultivars of tea plants (Camellia sinensis) using the tea PAL cDNA probe

Tea (Camellia sinensis) phenylalanine ammonia-lyase (PAL) cDNA was cloned using labelled rice PAL cDNA as a probe. The PAL genes of the tea plant were investigated by restriction fragment length polymorphism (RFLP) analysis using tea PAL cDNA. PAL genetic variation in tea plants was much larger than predicted due to the presence of various hybridized fragments in the Assam hybrids, which are hybrids between C. sinensis var assamica and var sinensis. On the other hand, hybridized band patterns of Japanese green tea cultivars belonging to var sinensis could be divided into five groups. Furthermore, a short-length PAL probe, about 280 bp including the 3 untranslated sequence, detected 3 DNA fragments of different lengths, which were named A, B and D. An experiment tracing the PAL gene heredity showed that A, B and D fragments were inherited according to the Mendelian monogenic ratio. Therefore, PAL genes identifiable by A, B and D fragments are multiple alleles, and the PAL gene is present as a single gene in the tea haploid genome. It was also clear that five groups of Japanese green tea cultivars were characterized by the composition of these PAL fragments. From RFLP analysis using tea PAL cDNA, we succeeded in distinguishing Assam hybrids and Japanese green tea cultivars with high and low catechin content, respectively, and in grouping Japanese green tea at the cultivar level.     

The “small but healthy” hypothesis: Historical,political, and ecological influences on nutritional standards

How accurate international nutritional standards are for recommending and assessing adequate nutrient intake and nutritional status of different national populations has been debated by nutritionists, economists, and others. This paper reviews the assumptions and possible motivations behind the design and interpretation of standards in particular countries, with a special emphasis on India and Mexico. The analysis suggests that comparative studies of the ethnonutrition concepts of policy-makers are useful for understanding how standards are set, and their nutritional implications.Substantially revised paper originally presented in the symposium Standards and Reference Values: Problems and Pitfalls for Nutritional Anthropologists at the Annual Meeting of the American Anthropological Association, Chicago, Illinois, November 17, 1983.     

Purification and properties ofβ-fructofuranosidase from Aspergillus japonicus

-Fructofuranosidase fromAspergillus japonicus, which produces 1-kestose (O--d-fructofuranosyl-(21)--d-fructofuranosyl -d-glucopyranoside) and nystose (O--d-fructofuranosyl-(21)--d-fructofuranosyl-(21)--d-fructofuranosyl -d-glucopyranoside) from sucrose, was purified to homogeneity by fractionation with calcium acetate and ammonium sulphate and chromatography with DEAE-Cellulofine and Sephadex G-200. Its molecular size was estimated to be about 304,000 Da by gel filtration. The enzyme was a glycoprotein which contained about 20% (w/w) carbohydrate. Optimum pH for the enzymatic reaction was 5.5 to 6. The enzyme was stable over a wide pH range, from pH 4 to 9. Optimum reaction temperature for the enzyme was 60 to 65°C and it was stable below 60°C. The K_m value for sucrose was 0.21m. The enzyme was inhibited by metal ions, such as those of silver, lead and iron, and also byp-chloromercuribenzoate.     

Sarcolemmal calcium binding sites in heart: II. Mathematical model for diffusion of calcium released from the sarcoplasmic reticulum into the diadic region

Summary We present a model for predicting the temporal and spatial dependence of [Ca] in the cardiac subsarcolemmal diadic region (cleft), following Ca release from the feet of the sarcoplasmic reticulum. This region is modeled as a disc 10 nm thick, 430 nm in radius, with or without Ca binding sites and open at its periphery to the cytosol. [Ca] is computed for three diffusion coefficients (100, 20 and 4% of aqueous diffusion), following release of a 20-msec square pulse sufficient to produce 50% maximal contractile force, or repetitive release (400/min) of such pulses. Numerical solutions are obtained for the general diffusion/binding problem and analytic solutions for the case of no binding sites. For the middle value of diffusion coefficient, and in the absence of binding sites, [Ca] rises to 1.5 mm in 20-msec and then falls to 0.1 m in < 3 msec. Adding binding sites reduces peak [Ca] to 0.6 mm but prolongs its decline, requiring 200 msec to reach 20 m. For repetitive release [Ca] is > 100 m for roughly half of each cycle. Two major implications of the predicted [Ca] are: (i) The effect of Ca binding sites on [Ca] will cause Ca efflux from the cleft via the NaCa exchanger (K _m (Ca) 20 m) to continue at a significant level for > 200 msec, (ii) The time constant for inactivation of release from the feet must be much greater than for activation if Cainduced Ca release is to continue for > 1–2 msec.     

Purification and characterization of α(2-6)-sialyltransferase from human liver

A Gal1-4GlcNAc (2-6)-sialyltransferase from human liver was purified 34 340-fold with 18% yield by dye chromatography on Cibacron Blue F3GA and cation exchange FPLC. The enzyme preparation was free of other sialyltransferases. It did not contain CMP-NeuAc hydrolase, protease, or sialidase activity, and was stable at –20°C for at least eight months. The donor substrate specificity was examined with CMP-NeuAc analogues modified at C-5 or C-9 of theN-acetylneuraminic acid moiety. Affinity of the human enzyme for parent CMP-NeuAc and each CMP-NeuAc analogue was substantially higher than the corresponding Gal1-4GlcNAc (2-6)-sialyltransferase from rat liver.Abbreviations FPLC fast protein liquid chromatography - NeuAc 5-N-acetyl-d-neuraminic acid - 9-amino-NeuAc 5-acetamido-9-amino-3,5,9-trideoxy-d-glycero-2-nonulosonic acid - 9-acetamido-NeuAc 5,9-diacetamido-3,5,9-trideoxy-d-glycero--d-2-nonulosonic acid - 9-benzamido-NeuAc 5-acetamido-9-benzamido-3,5,9-trideoxy-d-glycero--d-galacto-2-nonulosonic acid - 9-fluoresceinyl-NeuAc 9-fluoresceinylthioureido-NeuAc - 5-formyl-Neu 5-formyl--d-neuraminic acid - 5-aminoacetyl-Neu 5-aminoacetyl--d-neuraminic acid - CMP-NeuAc cytidine-5-monophospho-N-acetylneuraminic acid - G_M1 Gal1-3GalNAc1-4(NeuAc2-3)Gal1-4Glc-ceramide - ST sialyltransferase - DTE 1,4-dithioerythritol Enzyme: Gal1-4GlcNAc (2-6)-sialyltransferase, EC 2.4.99.1.     

Interactions of γ-L-glutamyltaurine with excitatory aminoacidergic neurotransmission

The in vitro effects of -L-glutamyltaurine on different stages of excitatory aminoacidergic neurotransmission were tested with -D-glutamyltaurine as reference. -L-Glutamyltaurine enhanced the K⁺-stimulated release of [³H]glutamate from cerebral cortical slices (25% at 0.1 mM) and slightly inhibited the uptake by crude brain synaptosomal preparations (about 10% at 1 mM). -L-Glutamyltaurine was also a weak displacer of glutamate and its agonists from their binding sites in brain synaptic membrane preparations, being, however, less selective to quisqualate (QA) sites than -D-glutamyltaurine. The basal influx of Ca²⁺ into cultured cerebellar granular cells was not affected by 1 mM -L-glutamyltaurine, but the glutamate- and its agonist-activated influx was significantly inhibited in low-Mg²⁺ (0.1 mM) and Mg²⁺-free media. The glutamate-evoked increase in free intracellular Ca²⁺ and the kainate-activated formation of cGMP in cerebellar slices were both markedly inhibited by 0.1 mM -L-giutamyltaurine. We propose that -L-glutamyltaurine may act as endogenous modulator in excitatory aminoacidergic neurotransmission.     

Properties of Aspergillus japonicus β-fructofuranosidase immobilized on porous silica

-Fructofuranosidase from Aspergillus japonicus MU-2, which produces fructo-oligosaccharides (1-kestose: O--D-fructofuranosyl-(2 1)--D-fructofuranosyl -D-glucopyranoside); and nystose: O--D-fructofuranosyl-(2 1)--D-fructofuranosyl-(2 1)--D-fructofuranosyl -D-glucopyranoside) from sucrose, was immobilized, covalently with glutaraldehyde onto alkylamine porous silica, at high efficiency (64%). Optimum pore diameter of porous silica for immobilization of the enzyme was 91.7 nm. After immobilization, the enzyme's stabilities to temperature, metal ions and proteolysis were improved, while its optimum pH and temperature were unchanged. The highest efficiency of continuous production of fructo-oligosaccharides (more than 60%), using a column packed with the immobilized enzyme, was obtained at 40% to 50% (w/v) sucrose. The half-life of the column during long-term continuous operation at 55°C was 29 days.     

Cloning,expression and characterization of a beta-agarase gene from a marine bacterium,Pseudomonas sp. SK38

A gene (pagA) encoding -agarase from Pseudomonas sp. SK38 was cloned and expressed in Escherichia coli. The structural gene consists of 1011 bp encoding 337 amino acids with a predicted molecular weight of 37326 and has a signal peptide of 18 amino acids. The deduced amino acid sequence showed 57% and 58% homology to -agarase from Pseudoalteromonas atalntica and Aeromonas sp., respectively. The recombinant enzyme was purified and biochemically characterized. The enzyme had maximum activity at pH 9 and 30 °C. It was stable at pHs from 8 to 9 and below 37 °C.     

Highly efficient production ofl-cystathionine fromO-succinyl-l-homoserine andl-cysteine byStreptomyces cystathionine γ-lyase

Summary Utilizing the -replacement reaction ofStreptomyces cystathionine -lyase (EC 4.4.1.1.), an efficient production method forl-cystathionine has been established. Under optimal conditions, 50 mMl-cystathionine was synthesized from 50 mMO-succinyl-l-homoserine and 50 mMl-cysteine, added in four stages to the reaction mixture, with a substrate conversion rate of 100%. This productivity (11 gl^-1 of reaction mixture) is about 3.5 times higher than that withl-homoserine andl-cysteine as substrates.Recipient of a JSPS Fellowship for Japanese Junior Scientists     

Über die Eignung von Naphthyl-α-l-fucosiden zur Untersuchung der α-l-Fucosidasen

Zusammenfassung Verglichen mit 1- und 2-Naphthyl--d-glucosid,--d-galactosid,--d-glucuronid,--d-N-acetylglucosaminid,--d-glucosid,--d-galactosid und--d-mannosid werden 1- und 2-Naphthyl--l-fucosid schneller oder im gleichen Ausmaß von Homogenaten verschiedener Rattenorgane hydrolysiert. Trotzdem fällt der histochemische Nachweis der -l-Fucosidasen methodenunabhängig im Gegensatz zu dem der anderen Glykosidasen überwiegend negativ aus. Ursache dafür ist die massive Hemmung der -l-Fucosidase durch Aldehydfixation und Diazoniumsalze; die Inhibitionsrate liegt bei 90% bzw. zwischen 85 und 98%; die - und -d-Glucosidase, - und -d-Galactosidase, -d-Mannosidase, -d-Glucuronidase sowie -d-N-Acetylglucosaminidase werden durch Aldehydfixation oder Kuppler höchstens zu 70% gehemmt. Daher können 1- und 2-Naphthyl--l-fucosid für die histochemische Darstellung der -l-Fucosidase nicht einschränkungslos empfohlen werden. Kleine Mengen Dimethylformamid hemmen die meisten Glykosidasen nicht.Für biochemische Messungen der -l-Fucosidase eignet sich speziell 1-Naphthyl--l-fucosid und läßt sich an Stelle von p-Nitrophenyl--l-fucosid werwenden. Bei der fluorometrischen Untersuchung der -l-Fucosidase in Rattenorganen mit dem 2-Naphthylderivat ergeben sich bemerkenswerte Aktivitätsunterschiede.

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Suitability of naphthyl--l-fucosides for the investigation of -l-fucosidases

Summary In comparison with 1- and 2-naphthyl -d-glucoside, -d-galactoside, -d-glucuronide, -d-N-acetylglucosaminide, -d-glucoside, -d-galactoside and -d-mannoside 1- and 2-naphthyl -l-fucoside are hydrolyzed more quickly or to the same extent by homogenates prepared from freezedried cryostate sections of various rat organs. Nevertheless, when the fucosides are employed for the histochemical demonstration of -l-fucosidase mostly negative data were obtained independent on the method used, whereas all other naphthyl glycosides deliver positive results. The reasons for these discrepancies are the marked inhibition of -l-fucosidase by aldehyde fixation and diazonium salts. Then, -l-fucosidase activity is suppressed to 90% and between 85 and 98% respectively; the inhibition of - and -d-glucosidase, - and -d-galactosidase, -d-mannosidase, -d-glucuronidase and -d-N-acetylglucosaminidase by the fixative or coupling reagent does not exceed 70%. Therefore 1- and 2-naphthyl -l-fucoside cannot be recommended in general for histochemical purposes. Small amounts of dimethylformamide do not influence the activity of most of the glycosidases investigated.For biochemical measurements, however, especially 1-naphthyl -l-fucoside represents a suitable alternative in a fluorometric procedure instead of p-nitrophenyl -l-fucoside used for the photometric evaluation of -l-fucosidase. With the fluorometric method the enzyme was measured in rat organs, which posses remarkably different activities of -l-fucosidase.