Transaminase and transferase activities in the pancreatic islet tissue of the teleostCottus quadricornis L.

Zusammenfassung Im isolierten Inselgewebe aus dem Pankreas des TeleostiersCottus quadricornis L. werden verhältnismässig hohe Aktivitäten von Glutaminoxalessigsäure-Transaminase (GOT), Glutaminpyruvatsäure-Transaminase (GPT) und Ornithin-Carbamyl-Transferase (OCT) gefunden)     

Transaminase in seminal plasma of man

Résumé La transaminase glutamo-oxaloacetique (GO-T) a été déterminée dans le liquide spermatique de l'homme après la séparation des spermatozoïdes. On a trouvé des valeurs élevées pour la GO-T dans le sperme normal et une diminution accentuée dans les cas d'oligospermie et surtout d'azoospermie. Les conditions de la prostate et des vésicules séminales semblent être responsables de cet abaissement de l'activité enzymatique puisque le liquide sans spermatozoïdes (azoospermie) présente encore une activité bien marquée.     

Reversion of Lactobacillus lactis protoplasts

More than 99% of L. lactis cells have been converted to protoplasts upon digestion of cell walls with mutanolysin (N-(acetyl)muramidase). Functional protoplasts were obtained even with the lowest level of the enzyme that was used (0.1 U.ml-1 of the cell suspension) and after incubation at 37 degrees C for 2 min. The regeneration of the polymerized cell wall appears to be induced by a cell homogenate of the same organism.     

High-frequency fusion of fungal protoplasts

Zusammenfassung Es gelang, die intraspezifische Protoplastfusion vonAspergillus flavus, A. nidulans, A. niger, Penicillium frequentans undP. ramigena mit grosser H?ufigkeit zu verwirklichen. Die Fusionsh?ufigkeit wurde durch Komplementation von Mangelmutanten festgestellt.

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The authors thank Dr.M. Czakó, Dr.M. Pesti and Mr.L. Manczinger for producing and characterizing some of the required mutants, andéva Sziráki andMagdolna Romvári for skilful technical assistance.     

Increased fusion frequency ofAspergillus nidulans protoplasts

Zusammenfassung Die Häufigkeit der Protoplastfusion auxotropher Mutanten vonAspergillus nidulans wurde durch Zugabe von 0.6M KCl oder NaCl gesteigert.

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The authors thank Dr.R. F. Rosenberger for the strainAspergillus nidulans pabal,y, ts6; ProfessorJ. G. H. Wessels and Dr.O. M. H. de Vries for discussions, and Dr.I. Rojik for help in electron microscopy.     

Transfer of isolated nuclei into protoplasts ofAspergillus nidulans

Nuclei were isolated from protoplasts of a haploid auxotrophicAspergillus nidulans strain. Transformation of protoplasts prepared from a complementary haploid auxotrophic strain with these purified nuclei resulted in both heterokaryotic and diploid colonies. The nutritionally-complementing colonies appeared at a frequency of 5×10^–7 to 10^–8.     

Regeneration of plants from mesophyll protoplasts ofAtropa belladonna

Summary Isolated leaf mesophyll protoplasts ofAtropa belladonna when cultured in defined liquid culture media regenerate cell walls, divide and form calli. Subsequent induction of shoot and root organogenesis leads to plantlets which grow to maturity after transfer to soil.Acknowledgment. We are indebted to Václav Mandák for skilful technical assistance.     

Effect of wall-degrading enzymes on protoplasts transaminase activity

Résumé Les enzymes employées pour l'obtention enzymatique des protoplastes de racines (Allium) altèrent les transaminases (EC. 2.6.1.1.) de protoplastes mécaniquement préparés. Cette inhibition transaminasique est partiellement levée lorsque les protoplastes ne sont plus en contact avec ces enzymes. Les effets des enzymes dégradant les parois cellulaires sont discutés relativement aux propriétés biochimiques des protoplastes.     

Transfer of isolated nuclei into protoplasts of Aspergillus nidulans.

Nuclei were isolated from protoplasts of a haploid auxotrophic Aspergillus nidulans strain. Transformation of protoplasts prepared from a complementary haploid auxotrophic strain with these purified nuclei resulted in both heterokaryotic and diploid colonies. The nutritionally-complementing colonies appeared at a frequency of 5 x 10(-7) to 10(-8).     

Effects of abscisic acid on photosynthesis of protoplasts fromPetunia hybrida

Zusammenfassung Inkubation mit Abscisinsäure verursacht bei Mesophyll-Protoplasten vonPetunia hybrida einen Anstieg der Photosyntheserate.     

Isolation and fusion studies on protoplasts from pollen tetrads

Summary different enzymes were tested for isolation of intact protoplasts from pollen tetrads. About 80% isolation was achieved from pollen tetrads of Cajanus cajan and Zea mays and about 60% from Luffa cylindrica and Lycopersicon esculentum after 4 h of treatment with 5% cellulase. When these mononucleate protoplasts were incubated in presence of 0.05 M CaCl₂ in 0.3 M glucose at pH 10.5, 70–80% fusion was achieved. Fusion was rare in sodium nitrate solutions.This work was supported by a grant from the Indian Council of Agricultural Research, New Delhi (No. 1-32/73, Ed. I) in the form of a Senior Fellowship awarded to P. C. D.Work carried out at Molecular Cytogenetics Research Unit, Dept. of Genetics and Plant Breeding, Banaras Hindu University, Varanasi, India.     

Ethylene production and cell wall formation in mesophyll protoplasts

Summary The regulation of ethylene synthesis, in relation to the presence of a new cell wall, has been investigated forNicotiana sylvestris leaf protoplasts. It is clear that the production of ethylene is not controlled by the new wall, which has no action on the ethylene formation. The addition of dichlorobenzonitrile to cultivated protoplasts causes the inhibition of wall formation, without any other apparent deleterious effects.     

The use of fungal protoplasts in the study of aflatoxin biosynthesis

Summary Protoplasts derived fromAspergillus flavus are shown to be capable of synthesizing aflatoxins when incubated in a chemically defined medium.¹⁴C-Acetate and¹⁴C-Versicolorin A, added to protoplasts from 3-day-old mycelium, are incorporated into aflatoxin B₁.     

Menadione-induced apoptosis and the degradation of lamin-like proteins in tobacco protoplasts

Detection of stereotypic hallmarks of apoptosis during cell death induced by menadione, including DNA laddering and the formation of apoptotic bodies, is reported. Comet assay and the TdT-mediated dUTP nick end labelling (TUNEL) procedure were also performed to detect DNA fragmentation. Inhibition of DNA fragmentation by Ac-Asp-Glu-Val-Asp-aldehyde (Ac-DEVD-CHO) and phenylmethylsulfosyl (PMSF) implicated the involvement of caspase-like proteases in menadione-induced apoptosis in plants. We further studied the cleavage of lamin-like proteins during apoptosis in menadione-treated tobacco protoplasts. In animals, it has been reported that the solubilization of nuclear lamina and lamin degradation occurs during apoptotic cell death. However, little is known about the fate of lamins in apoptotic plant cells. Our study provided evidence that lamin-like proteins degraded into 35-kDa fragments in tobacco protoplasts induced by menadione, and this preceded DNA fragmentation. The results thus indicated that proteolytic cleavage of nuclear lamins was also conserved in programmed cell death in plants. Received 16 November 1998; received after revision 21 December 1998; accepted 23 December 1998     

Loss of the ability to oxidize hydrocarbons in protoplasts ofCandida lipolytica

Zusammenfassung Aus den Zellen der HefeCandida lipolytica wurden Protoplasten gewonnen, die die Oxydationsfähigkeit gegenüber Hexadekan verloren haben, während diejenige gegenüber Glukose erhalten geblieben ist. Der Verlust der Fähigkeit, den Kohlenwasserstoff zu oxydieren, wird entweder durch eine Veränderung der Oberfläche der zytoplasmatischen Membran und Destruktion des an sie gebundenen Oxydationsenzyms erklärt oder dadurch, dass die Protoplasten die Fähigkeit verloren haben, Kohlenwasserstoffe in die Zelle zu transportieren.     

Isolation and fusion studies on protoplasts from pollen tetrads.

Different enzymes were tested for isolation of intact protoplasts from pollen tetrads. About 80% isolation was achieved from pollen tetrads of Cajanus cajan and Zea mays and about 60% from Luffa cylindrica and Lycopersicon esculentum after 4 h of treatment with 5% cellulase. When these mononucleate protoplasts were incubated in presence of 0.05 M CaCl2 in 0.3 M glucose at pH 10.5, 70-80% fusion was achieved. Fusion was rare in sodium nitrate solutions.