Gregorio Nicolás

• PhD
• Professor Emeritus at University of Salamanca

By means of an RT-PCR approach we isolated a specific tyrosine phosphatase (FsPTP1) induced by abscisic acid (ABA) and correlated with seed dormancy in Fagus sylvatica seeds. To provide genetic evidence of FsPTP1 function in seed dormancy and ABA signal transduction pathway, we overexpressed this gene in Cape Verde Island ecotype of Arabidopsis tha...

The functional protein phosphatase type 2C from beechnut (Fagus sylvatica; FsPP2C1) was a negative regulator of abscisic acid (ABA) signaling in seeds. In this report, to get deeper insight on FsPP2C1 function, we aim to identify PP2C-interacting partners. Two closely related members (PYL8/RCAR3 and PYL7/RCAR2) of the Arabidopsis (Arabidopsis thali...

Salicylic acid (SA) is a plant hormone mainly associated with the induction of defense mechanism in plants, although in the last years there is increasing evidence on the role of SA in plant responses to abiotic stress. We recently reported that an increase in endogenous SA levels are able to counteract the inhibitory effects of several abiotic str...

Exogenous application of gibberellic acid (GA(3)) was able to reverse the inhibitory effect of salt, oxidative, and heat stresses in the germination and seedling establishment of Arabidopsis (Arabidopsis thaliana), this effect being accompanied by an increase in salicylic acid (SA) levels, a hormone that in recent years has been implicated in plant...

FsPP2C2 was previously characterized in Fagus sylvatica L. seeds as a functional protein phosphatasetype-2C (PP2C). The expression of the FsPP2C2 gene is strongly upregulated by abscisic acid(ABA) in seeds and vegetative tissues. Since transgenic work is not feasible in Fagus, we have usedan overexpression approach in Arabidopsis (Arabidopsis thali...

FsPP2C1 is a functional protein phosphatase type-2C (PP2C) isolated from beech (Fagussylvatica L.) seeds. Previously, this gene was shown to be upregulated by abscisic acid (ABA)treatment and specifically expressed in ABA-treated seeds. It was demonstrated that constitutiveFsPP2C1 overexpression in Arabidopsis (Arabidopsis thaliana (L.) Heynh.) con...

Several gibberellic acid (GA3)-induced cDNA fragments encoding putative serine/threonine protein phosphatase (PP) 2A catalytic subunits were obtained by means of differential reverse transcriptase-PCR approach. The full-length clone, named FsPP2A1, isolated from a beechnut cDNA library, exhibited all the features of and homology to members of the P...

A functional abscisic acid (ABA)-induced protein phosphatase type 2C (PP2C) was previously isolated from beech (Fagus sylvatica) seeds (FsPP2C2). Because transgenic work is not possible in beech, in this study we overexpressed this gene in Arabidopsis (Arabidopsis thaliana) to provide genetic evidence on FsPP2C2 function in seed dormancy and other...

An abscisic acid (ABA)-induced cDNA fragment encoding a putative serine/threonine protein kinase (PK) was obtained by means of differential reverse transcriptase-polymerase chain reaction (RT-PCR). The full-length clone (FsPK4) was isolated from a cDNA library constructed using mRNA from ABA-treated Fagus sylvatica L. seeds. This clone contained th...

Indoleacetic acid (IAA), a factor that induces growth in epicotyls of cicer arietinum L. cv. Castellana, increases the autolytic capacity of the cell walls by 50%, suggesting that autolysis is related to the processes of cell wall loosening that accompany growth. IAA promotes an increase in the specific activities of the enzymes involved in autolys...

The protein extracted from the cell wall of the epicotyls of Cicer arietinum L. cv. Castellana was separated by ion exchange chromatography in four different fractions with β-D-galactosidase (EC 3.2.1.23) activity. These were called βI, βII, βIII and βIV, according to their order of elution. βII was associated with a particularly high β-D-glucosida...

The effect of abscisic acid (ABA) and CaCl2 in the medium on RNA synthesis in embryonic axes of seeds of chick-pea (Cicer arietinum L. cv. Castellana) during the first hours of germination has been studied. ABA decreases the incorporation of 3H-uridine in the embryonic axes and modifies the mRNA populations by preventing the disappearance of three...

Sánchez, O.J., Pan, A., Nicolás, G. and Labrador, E. 1989. Relation of cell wall peroxidase activity with growth in epicotyls of Cicer arietinum. Effects of calmodulin inhibitors. Peroxidases are bound ionically to cell walls in epicotyls of Cicer arietinum L. cv. Castellana. The cell wall peroxidase activity increases during the growth of epicotyl...

The Hw pectic fraction, extracted with hot water, is the major component of 4 days old epicotyl cell walls of Cicer arietinum L. cv. Castellana and is formed of arabinose and galactose, with smaller amounts of rhamnose, xylose, glucose and mannose. The cell wall 2βIII enzymatic fraction, with β-galactosidase activity (EC 3.2.1.23) and the main enzy...

Oryza sativa L. var. bahia coleoptile cell walls show sufficient autolytic activity for the release into the surrounding medium of amounts up to 60 μg of sugars per mg of dry weight of cell wall. The products released elute in Bio-gel P.2 as mono- and polysaccharides with glucose as the sole component. The polysaccharide component releases tri- and...

The autolytic process in epicotyl cell walls of Cicer arietinum L. cv. Castellana, and also the hydrolysis of heat-inactivated cell walls as mediated by a cell wall β-galactosidase (EC 3.2.1.23) (named βIII and previously characterized as responsible for the autolysis), are maximal on the fourth day of germination and coincide with the maximal grow...

An enzymatically active recombinant protein kinase, previously isolated and characterized in Fagus sylvatica L. dormant seeds (FsPK1), was used to obtain a specific polyclonal antibody against this protein. Immunoblotting and immunohistochemical analysis of FsPK1 protein in beech seeds showed a strong immunostaining in the nucleus of the cells loca...

In the present paper evidence is presented indicating that tyrosine dephosphorylation is a key regulatory mechanism in postgermination arrest of Arabidopsis thaliana L. seed development mediated by abscisic acid (ABA). By using phenylarsine oxide (PAO), an inhibitor of tyrosine phosphatases, the sensitivity to the inhibitory effect of ABA on seed g...

By means of reverse transcriptase-polymerase chain reaction, using degenerate oligonucleotides conserved among ethylene-responsive transcription factors, we have isolated and characterized a cDNA clone encoding a protein involved in ethylene signalling during the breaking of dormancy in Fagus sylvatica L. seeds. This clone, named FsERF1, exhibits h...

Gibberellin 20-oxidase (GA 20-oxidase) is an enzyme that catalyses the last three steps in the synthesis of active GAs and is a potential control point in the regulation of GA biosynthesis. Reverse transcriptase-polymerase chain reaction with degenerated oligonucleotides conserved among GA 20-oxidases was used to isolate a cDNA clone for this enzym...

1-aminocyclopropane-1-carboxylic acid (ACC) oxidase is a key enzyme in the ethylene biosynthesis pathway. In the present report the changes in ACC content, ACC oxidase activity and ethylene production have been examined in Fagus sylvatica L. dormant seeds after stratification and different treatments that maintain or release dormancy. Additionally,...

Dormancy and desiccation tolerance were studied in Fagus sylvatica seeds subsequent to 0–26 weeks of either moist prechilling (5°C) or warm (15°C) pretreatment at a restricted water content of 34% (fresh weight basis), i.e. c. 5% below full imbibition. After the pretreatments, seeds were either fully imbibed at 5 or 15°C, or dried for 7 d to around...

An abscisic acid (ABA)-induced cDNA fragment encoding a putative protein kinase (PK) was obtained by differential screening of a cDNA library from Fagus sylvatica seeds. The full-length clone, named FsPK1, was produced by 5′ rapid amplification of cDNA ends (RACE) extension. This clone contained the 11 catalytic domains present in all protein kinas...

FsPP2C1 was previously isolated from beech (Fagus sylvatica) seeds as a functional protein phosphatase type-2C (PP2C) with all the conserved features of these enzymes and high homology to ABI1, ABI2, and PP2CA, PP2Cs identified as negative regulators of ABA signaling. The expression of FsPP2C1 was induced upon abscisic acid (ABA) treatment and was...

These proceedings contain 5 parts, which include several chapters each, discussing: seed development; seed germination and dormancy; desiccation and other stress tolerance, and conservation; seed ecology; and seed biotechnology.

Phosphorylation/dephosphorylation of proteins is a general mechanism of hormonal signal transduction, including ABA, and serine/threonine protein phosphatases 2C (PP2C, EC 3.1.3.16) have been suggested to play an important role in this process. By means of differential reverse transcriptase-polymerase chain reaction (RT-PCR) and further screening o...

A full-length cDNA clone, named FsA1, has been isolated from a cDNA library constructed using mRNA from Fagus sylvatica L. dormant seeds (beechnuts). This clone shows high identity with members of the AAA superfamily, for ATPases Associated with a variety of cellular Activities, encoding subunit 8 of the 26S proteasome or Tat binding proteins (TBPs...

An abscisic acid (ABA)-induced cDNA fragment encoding a putative protein phosphatase 2C (PP2C) was obtained by means of differential reverse transcriptase-polymerase chain reaction approach. The full-length clone was isolated from a cDNA library constructed using mRNA from ABA-treated beechnut (Fagus sylvatica) seeds. This clone presents all the fe...

A full‐length cDNA clone for calmodulin has been isolated from a cDNA library constructed from mRNAs of chick‐pea seeds germinated for 48 h in H20, using a calmodulin cDNA clone from Fagus sylvatica as a probe. The amino acid sequence of the clone shows high homology (> 80%) with other plant and animal calmodulins. The corresponding transcripts, an...

A cDNA clone was selected from a cDNA library constructed using mRNA from ABA-treated Fagus sylvatica L. dormant seeds as a template. The clone is highly expressed in the presence of ABA and tends to disappear in stratified seeds. A search of sequence databases showed that the clone encodes a small GTP-binding protein. By means of in situ hybridiza...

By differential screening of a cDNA library constructed from poly (A+) RNA of ABA-treated seeds of Fagus sylvatica L., we have isolated an ABA-responsive clone that is present in dormant seeds and under conditions that maintain dormancy, but it tends to disappear under conditions breaking seed dormancy. A search of the sequence data bases showed th...

The dormancy of Fagus sylvatica seeds is eliminated by cold treatment at 4°C over a period longer than 8 weeks. Application of GA3 is able to substitute for the cold treatment, while the application of ABA reverses the effect of low temperature and GA3 maintaining the seeds in the dormant state. In vitro translation of the mRNAs isolated from these...

Study of the factors involved in the dormancy of Fagus sylvatica seeds shows that such dormancy is due partly to the seed coats and partly to endogenous factors. Seed coat removal accelerates both the release from dormancy and the effects of the other treatments that abolish it. The dormancy of these seeds is eliminated by cold treatment at 4°C ove...

The effects of different types of stress on RNA and protein synthesis have been studied in embryonic axes of seeds of chick-pea (Cicer arietinum L.) during the first hours of germination as well as their relationship with the effects produced by exogenous application of abscisic acid (ABA) on this process. Stress induced by high (30 °C) and low (8...

Water stress inhibits germination of chick-pea seeds and produces specific changes in gene expression. some of which are coincident with those induced by the exogenous application of abscisic acid (ABA). Three cDNA clones, GAB-8, GAB-9 and GAB-11, were previously identified as under the regulation of ABA and osmotic stress in embryonic axes of germ...

The cDNA clone GAB-9 was selected from a cDNA gene library constructed from the mRNA of embryonic axes of chick-pea (Cicer arietinum L.) seeds imbibed for 12 h in the presence of abscisic acid. The sequence of this cDNA has an open reading frame of 546 nucleotides that code for 182 amino acids. The polypeptide encoded by the corresponding mRNA is o...

A cDNA library has been constructed using poly (A+) RNA isolated from embryonic axes of chick-pea (Cicer arietinum L. cv. Castellana) seeds germinated for 12 h in 50 μM abscisic acid (ABA). By differential screening three clones (designated GAB-8, GAB-9, GAB-11) regulated by ABA were identified. Northern analysis of these clones revealed that their...

Synthetic oligonucleotides corresponding to conserved regions of cysteine proteinases were used as primers in the RT-PCR amplification of a fragment of cDNA corresponding to a region of a cysteine proteinase gene expressed during germination of chickpea (cac for Cicer arietinum cysteine proteinase). The identity of the PCR-amplified fragment was co...

Of the eight endogeneous cytokinins detected in cotyledons of Cicer arietinum L. seeds, isopentenyl adenine riboside exerts its main effect on the metabolism of reserve lipids and is less efficient with respect to the metabolism of carbohydrates and proteins. Isopentenyl adenine only has a regulatory effect on carbohydrate metabolism.

Fractionation and partial purification of the proteins extracted from cell walls of Cicer arietinum epicotyl reveal the presence of two fractions with peroxidase activity, denominated Px-1 and Px-2 according to their order of elution from a SP-Sephadex chromatography column. The specific activity of the Px-2 fraction increases with the age of the e...

In the embryonic axes of Cicer arietinum L. a compartmentalization of the different groups of the cytokinins was observed. Conjugated cytokinins were found to be located in the basal zones of the hypocotyl and epicotyl. The free bases appeared at the highest concentrations in the apical zones of the axis. Conversion of the free bases into their cor...

During the germination and primary growth of chick-pea seedlings two clearly differentiable phases are observed in the development of α-amylase activity. The activity detected is thermolabile and is negatively affected by the absence of the embryonic axis. A short pulse of red light is able to substitute the effect of the axis in inducing α-amylase...

In chick-pea seeds, the exogenous application of calcium decreases the content of this ion in the embryonic axes, the decrease being inversely proportional to the calcium concentration applied. Application of cytokonins, in particular that of zeatin, however, increases the levels of endogenous calcium in the axes. The highest levels of calcium are...

In the cell walls of epicotyls of Cicer arietinum we found β-glucosidase and α-galactosidase activities, the former being predominant. We purified and characterized these enzymatic activities. The β-glucosidase activity is found associated with a protein fraction that also shows β-galactosidase and β-xylosidase activity. It is formed by two subunit...

During the germination of chick-pea seeds, the absence of the embryonic axis markedly reduces the degradation of proteins located in protein bodies. All the enzymes studied - aminopeptidase, carboxypeptidase and caseinases - were found both in the albumin fraction and in the fraction of membrane-bound proteins (MBP) of the protein bodies. In the ab...

During the growth of Cicer arietinum epicotyls an increase in specific cell wall β-glucosidase and β-galactosidase activities were observed. In contrast, the amount of cell wall proteins extracted with 3 M LiCl decreased between the third and the fourth day of germination, remaining constant up to the seventh day. Partial purification of the cell w...

β-Galactosidase (EC 3.2.1.23) has been established as the main enzyme involved in the autolytic process. The enzyme extracted from cell walls of epicotyls of Cicer arietinum L. cv. Castellana with 3 M LiCl is a 45 kDa protein composed of a single subunit, having an optimum pH of 4; an optimum temperature of 45°C and Km and Vmax of 1.72 mM and 18.5...

The embryonic axis plays an essential role in the mobilization of the main reserves of the cotyledons of seeds of Cicer arietinum L. cv Castellana. This control by the axis of the metabolism of the storage products of the cotyledons largely takes place through the cytokinins, which are transported from the embryonic axis to the cotyledons where the...

In chick-pea seeds, the axis seems to have a clear regulatory role in the processes involved in protein degradation since in its absence very little protein degradation is recorded. However, its effect on proteolytic enzymes varies according to the enzyme studied, as does the pH at which each of these enzymes exhibits its maximal activity. The appl...

The type of cytokinins evaluated and identified when seeds were germinated with red light and with red light followed by far-red light were the same as those observed when germination was carried out in darkness. Red light affected the behaviour of endogenous cytokinins. An increase was observed in the appearance of free bases in the cotyledons par...

Changes in calmodulin (CaM) levels in embryonic axes of Cicer arietinum L. cv. Castellana germinated under three different conditions were measured. Abscisic acid (ABA) and a temperature of 30°C, which delay chick-pea germination, respectively decreased and increased the concentration of CaM compared to the values obtained under normal germinating...

Two protein fractions with activity as α-galactosidase (EC 3.2.1.22) and α-arabinosidase (EC 3.2.1.55), respectively, were identified in the proteins of cell wall of Cicer arietinum L. cv. Castellana extracted with 3 M LiCl. These fractions were partially purified by gel filtration chromatography (Bio Gel P-150), increasing the specific arabinosida...

The effect of short chain fatty acids on the cellular permeability of embryonic axis inGcer arietinum seeds was studied. Octanoic (OCT) and nonanoic (NON) adds, which reduce both germination and growth of the embryonic axis and raise the inhibitor effects of the supraoptimal temperatures (30‡C), induce a greater ionic efflux into the medium (conduc...

Peroxidases have been implicated in the regulation of growth, and several different biochemical pathways have been proposed to account for their mechanism of action. At first, it was thought that these enzymes controlled endogenous auxin levels (Srivastava et al., 1973). Later, these substances were considered as growth regulators, exerting their a...

Chick-pea seeds have an optimal germination temperature of 25°C. A temperature of 30°C induces a delay of approximately 24 hours in the germination of these seeds and also a 24–36 hours delay in the appearance of cytokinins in the cotyledon, the transformation of glycosides into free bases and of free bases into dihydroderivatives. The transport of...

The embryonic axis plays an important role in the processes of starch degradation. Before germination starts, the starch granules of chickpea cotyledons have an almost smooth surface. As germination progresses, membrane-like material is deposited on the granules from the adaxial to the abaxial face of the cotyledon. At 10 days after the start of ge...

Treatment of excised cotyledons with both endogenous dihydrozeatin (DHZ) and Ca2+ or Ca2+ plus the ionophore A-23187 produces a similar effect to that of the embryonic axis on the catabolism of starch granules. Under the three kinds of treatment a progressive degradation of the granules occurs from the adaxial to the abaxial zone on the 4th day of...

During the growth of turnip seedlings, two new lipases have been demonstrated, one with a maximum activity at pH 4.5 (acid lipase) and the other with a maxima at pH 8.6 (alkaline lipase). Many different enzymes are involved in gluconeogenesis: catalase, isocitrate lyase, malate synthetase, malate dehydrogenase, aconitase, citrate synthetase, fumara...

Turnip tops seeds have a high lipid content (47.22% dry wt.); there is clear predominance of neutral lipids, mainly triglycerides, which represent 71.8% of the total lipid content.These triglycerides decrease during germination, with a maximum descent taking place between the 5th and 6th days of germination; this coincides with the maximum content...

The germination of seeds and growth of embryonic axes of Cicer arietinum L. are retarded or inhibited either by supraoptimal temperatures (30°C or above) or by the presence of abscisic acid (ABA). Both treatments delay the degradation of non-cellulosic cell wall sugars which takes place under normal germination conditions. It seems that this delay...

Eight cytokinins were detected in germinated chick-pea (Cicer arietinum L. var. Castellana) seeds. Treatments of extracts with β-glucosidase revealed the presence of two cytokinin glycosides: zeatin glucoside and glycosil zeatin riboside. Treatment with potassium permanganate allowed the differenciation of dihydrozeatin and dihydrozeatin riboside....

Cytokinins detected in chick-pea seeds were present in the embryonic axes and first appeared in the cotyledons after 12 hours of germination. The appearance and initial increase of cytokinins in cotyledons is common to both the free and bound forms. However, from 24 hours of germination onwards the disappearance of bound cytokinins is much faster t...

The products released in cell wall autolysis from 4-day-old epicotyls of Pisum sativum elute in gel filtration chromatography (Bio Gel P.2) as two components, mono and polysaccharides, in a practically constant ratio over the time of incubation. The polysaccharides are mainly composed of arabinose and galactose, with smaller amounts of xylose and g...

Calcium plays an important role in the regulation of plant metabolism and in mediating the adaptation of plants to environmental changes. Some of these functions are mediated through its binding to calcium binding regulatory proteins, the most important among these is calmodulin (CaM). We want to know if CaM has a role in the early stages of seed g...

Pisum sativum L. (cv. Lincoln) epicotyl cell walls show autohydrolysis and release into the incubation medium up to 120 μg of sugar per mg of cell wall dry weight in 30 h. Cell walls from younger epicotyls with high growth capacity showed higher auto-lytic capacity than older epicotyls. This suggests that both processes, growth and au-tolysis, are...

The in vitro activity of polysomal polyadenylated RNA (poly(A)RNA) was studied using chick-pea (Cicer arietinum L.) embryonic axes subjected to treatments retarding germination (H2O 30°C and abscisic acid [ABA] 30°C) or inducing a false germination (thiourea 30°C) in which normal protein synthesis and growth did not occur. All treatments induced a...

Nonanoic acid, which inhibits germination in several seeds, enhanced ion efflux from embryonic axes of Cicer arietinum L., especially at temperatures above 25°C. Other short chain fatty acids had little effect on germination and ion leakage. Nonanoic acid also decreased uptake of 86Rb+ and 22Na+ and increased efflux of both isotopes from the embryo...

1.1. β-galactosidase and α-mannosidase were isolated from extracts of cotyledons of germinating Lens culinaris.2.2. During germination an increase of about 2–3-fold in the activities of both enzymes is observed at 48 hr.3.3. Using column chromatography on DEAE-cellulose, two forms of Lens culinaris β-galactosidase and α-mannosidase activities were...

An increase in RNase activity dependent on embryonic axis was detected in cotyledons of Cicer arietiunm L. during the first 24 h. of germination. Experiments with cycloheximide suggest that activation and enzyme synthesis would take place. RNase activity had optimum pH and temperature, of 6.0 and 50ºC, respectively. Six bands of isoenzymes were det...

Changes in ninhydrin positive material, free amino acids and protein content during germination of seeds of Lens culinaris Med. have been studied. Ninhydrin positive material and free amino acids reached their highest concentration at the fifth day of germination. Total protein which represents 21% of the total dry weight of the lentil cotyledons,...

Two proteases, one peptidehydrolase and one aminopeptidase, have been purified to homogeneity from cotyledons of germinating seeds of Lens culinaris Med. Peptidehydrolase has an apparent molecular weight of 89,000 and an isoelectric point of 4.7. Peptidehydrolase activity was not affected by metal chelators but it was affected by N-bromosuccinimide...

Thiourea, hydroxyurea, phenylthiourea, methylurea, methylthiourea, thiosemicarbazide and 2,2-dithiodipyridine affected the germination of Cicer arietinum L. cv. Castellana (chick-pea) seeds. Microscopic observations of the subapical zone of the radicle showed that thiourea induced an increase in cell volume and length when compared with control see...

During the first 12 h of germination of Cicer arietinum L. (cv. Castellans) seeds, K+ is first lost into the surrounding medium and is later reabsorbed. Thiourea accelerates this reabsorption. Since there is an increase in the mobilization of K+ in response to thiourea, a greater accumulation of malate due to the carboxylation of phosphoenolpyruvic...

The growth capacity of the epicotyls of Cicer arietinum L. decreased from the sub-apical region to the basal region. The pectic fraction content falls from the upper to the lower part of the epicotyls. Contrary to this, the α-cellulose content was lower in the upper part and higher in the basal one. The hemicellulosic content was almost constant ov...

Measurements of total nucleic acid content of the embryonic axis of Cicer arietinum L. indicated that net synthesis of both DNA and RNA was initiated at 18 h. after the onset of germination. Incorporation studies with radioactive precursors showed that synthesis of RNA is detected within the third hour of imbibition of water. Whereas 5-FU inhibits...

The variation in the RNA of Cicer arietinum cotyledons during early germination has been studied. Total RNA was approximately constant over the 24 h of germination. However, ribosomal and messenger RNAs synthesis occurs during this time and is dependent on the embryo. The mRNA activity in dried cotyledons, assayed in the wheat germ system, did not...

A fractionation of non-cellulosic sugars of Oryza sativa L. coleoptile cell walls was carried out and the composition of each fraction was studied during coleoptile growth. Percentages of fractions extracted with boiling water and with oxalate (pectic substances) were almost constant throughout development. An increase in the K II hemicellulosic fr...

alpha-Amylase from the cotyledons of lentils germinated for 6 days (Lens culinaris, Medik) was purified by heat treatment, complexing with glycogen, Sephadex G-75 filtration and electrofocusing. Although three bands with alpha-amylase activity were separated in the purified extract from Sephadex G-75 filtration by polyacrylamide gel electrophoresis...

Germination and growth of seeds of Cicer arietinum L. are retarded or inhibited either by temperatures above 30°C or by the presence of abscisic acid (ABA). Both treatments affect the uptake of K+ and glucose. ABA may affect the properties of the cell membrane or the kinetics of the enzymes bound to it. Fusicoccin (FC) and thiourea (TU) are to a gr...

Polyadenylated RNA was isolated from total RNA extracted from cotyledons of ungerminated or 18-hour-germinated chick-pea seeds by affinity chromatography on oligo(dT)-cellulose. Both poly(A)-containing RNA fractions exhibited a template activity when assayed in two cell-free translation systems, wheat germ extracts, and nuclease-treated reticulocyt...

Changes in respiration rate during the early period of germination of Cicer arietinum L. seeds were studied. Three phases were distinguished. During phases I and II the RQ was higher than unity. Sodium fluoride showed no effect on gaseous exchange during phase I while in phases II and III a progressive increase in the inhibition of the respiratory...

1.1. Changes in the levels of glycolytic intermediates, adenosine phosphates and energy charge, were measured during the first 72 hr of germination of seeds of Cicer arietinum L.2.2. In cotyledons, all the glycolytic intermediates with the exception of glucose-6-phosphate and fructose 1,6-diphosphate reached the maximum level at 24 hr. ATP increase...

Changes in the level of nicotinamide nucleotides, rate of 14CO2 output from [1−14C] or [614 C6/C1 ratios, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and NAD kinase activities were determined during the first 72 h of germination of seeds of Cicer arietinum L. The level of oxidized and reduced forms of nicotinamide nucleotid...

The possibility of a biphasic response to auxin in rice coleoptiles has been investigated. The action of cytokinins and nojirimycin on the auxin-induced growth can not be used to distinguish between the two different growth phases in response to auxin in rice coleoptiles.

The variations in starch and soluble sugar content, in phosphorylase and amylase activities in cotyledons of germinating seeds of Cicer arietinum L. are determined. Results from various experiments prove that the alpha-amylases are chiefly responsible for amylase activity. Phosphorylase plays an important rôle during the first two days of germinati...

The combined action of the inhibitors antimycin A and cyanide with benzohydroxamic acid indicates the presence of a cyanide-resistant pathway of respiration in chick pea (Cicer arietinum L.) seeds. The appearance of this pathway takes place during germination. During the first 12 hours of germination, the respiration is predominantly cyanide-sensit...

Starch, total amylolytic and phosphorylase activities were determined in lentil cotyledons during the first days of germination. Several independent criteria show that the amylolytic activity is due mainly to an amylase of the alpha type. Starch is degraded slowly in the first days; during this time, alpha- and beta-amylase activity are very low, w...

The specific activities of some enzymes of the glycolytic and fermentative pathways varied during germination of seeds of Cicer arietinum L., both in cotyledons and growing embryos. The activities during the first 24 h of germination showed a more or less pronounced increase followed by an almost general decrease. This pattern of changes suggests a...

Carbon and nitrogen sources were found to be necessary both for the germination and swelling of the conidia of Penicillium notatum Westl. and Trichoderma lignorum (Tode) Harz. The addition of vitamins has no effect on swelling and germ-tube formation. The optimal pH is around 6, although the pH range for swelling is wider than for germ-tube formati...

Lomofungin inhibited the growth of some yeasts and mycelial fungi at concentrations between 5 and 10 mug/ml. At such concentrations, there was no decrease in endogenous and exogenous oxygen consumption, and even 50 mug of antibiotic per ml caused only slight decreases. The permeation of the cell membrane was changed so that leakage of ninhydrin-pos...