Showing papers by "University of Amsterdam published in 1969"
01 Aug 1969
TL;DR: The results of a palynological investigation of a 120 m deep borehole in the Tenaghi Philippon, Macedonia (Greece) are given in this paper, showing that during the Holocene mainly an oakwood forest was present.
Abstract: In this paper the results of a palynological investigation of a 120 m deep borehole in the Tenaghi Philippon, Macedonia (Greece) are given. These data show that during the Holocene mainly an oakwood forest was present. In the most recent part of the Holocene Fagus and Abies were also present. During the climatic extremes of the Weichselian an open vegetation existed. During the early interstadials a forest with Quercus, Fagus and Carpinus existed, whereas in the later interstadials stands of Pinus predominated. In the Late Glacial a not very dense oak forest was of some importance.
363 citations
TL;DR: In this paper, it is argued that when a gap exists between behavior and the meaning of the environment, such attribution may occur, and the classical theories of reasoning by analogy or empathy have been developed.
Abstract: Publisher Summary Recognition of emotion may be intuitive and immediate; this does not preclude the intervention of much knowledge and experience. It may consist of phenomenally immediate integrations in simple or well-known situations. Recognition of emotion often consists of conscious hypotheses and self-corrections, and it often involves explicit inferential activities, utilizations of former experiences, and reasonings by analogy. Based largely upon immediate appreciation of the positional, relational meaning of expressive behavior, recognition of emotion is a complex process that may vary from the immediately evident to the fully conscious making of plausible guesses. This applies, in particular, when one understands, or tries to understand, other people's inner experiences. To explain this puzzling human possibility, the classical theories of reasoning by analogy or empathy have been developed. Critics of these theories have objected that in most instances, nothing of the sort seems to occur. They are right, because perceiving the positional aspects of behavior seen in a situation does not involve attribution of inner experience or the cognitive activities necessary for it. However, when a gap exists between behavior and the meaning of the environment, such attribution may occur.
178 citations
TL;DR: The physicochemical properties, replication, and genetic function of mitochondrial DNA is discussed, and several aspects of mitochondrial biogenesis are discussed.
Abstract: Publisher Summary This chapter discusses the physicochemical properties, replication, and genetic function of mitochondrial DNA. The biosynthesis of functional mitochondria requires the cooperation of two genetic systems: the nuclear system, involving nuclear mRNA's, probably translated on extramitochondrial ribosomes, and a mitochondrial system localized in the mitochondrial matrix space. The genetic continuity and expression of the mitochondrial system appear to be ensured by the presence within the mitochondrial inner membrane of the enzymes required for DNA and RNA synthesis and the complete machinery required for protein synthesis. Since several vital parts of this machinery differ from their extramitochondrial counterparts (e.g., the ribosomes), the mitochondrial system for the synthesis of macromolecules is in part unique and not merely a copy of the extramitochondrial system stationed in the mitochondrial matrix space for the benefit of translating the information present in mitochondrial DNA. The chapter also discusses several aspects of mitochondrial biogenesis.
158 citations
TL;DR: The results show that successful propagation through the A-V node is at least partly determined by the direction of the atrial wave front, and this factor may play an important role during atrial fibrillation.
Abstract: Transmembrane potentials of A-V nodal cells in isolated rabbit hearts were recorded while the route of entry of atrial activity into the A-V node was changed by stimulating the atrium at a high, constant rate on eitherthe crista terminalis or the interatrial septum. Atrial activity arising from the interatrial septum provided a less effective input to the A-V node, as shown by the occurrence of 2 : 1 A-V conduction block, compared to 1 : 1 during driving on the crista terminalis at the same rate. The amplitude and rate of rise of the action potentials of most A-V nodal cells was smaller during driving on the interatrial septum, and many cells developed alarger or smaller "hump" in the repolarization phase, which was absent during stimulation on the crista terminalis. The pattern of A-V nodal excitation during stimulation on the crista terminalis was similar to that during spontaneous sinus rhythm, but was profoundly altered during stimulation on the interatrial septum. The results can be explained by assuming that an atrial wave front coming from the interatrial septum excites the atrial margin of the A-V node asynchronously, resulting in inhoinogeneous conduction within the node, causing longitudinal dissociation. The results show that successful propagation through the A-V node is at least partly determined by the direction of the atrial wave front. This factor may play an important role during atrial fibrillation.
151 citations
114 citations
111 citations
TL;DR: It is proved significantly that the poor ventilation of a fattening house may induce tail-biting, and that a daily ration of fresh straw diminishes the chances of tail- biting considerably, even if the climate in the fattens house is not satisfactory.
109 citations
TL;DR: The translocation of ADP and ATP through the inner membrane is rate-limiting for the process of oxidative phosphorylation in rat-liver mitochondria.
104 citations
TL;DR: The magnetic properties of two antiferromagnetic cobalt compounds, K2CoF4 and Rb2CoFs4, were studied in this paper, and it was shown that the magnetic exchange between the cobalt ions is strongly anisotropic, making the two compounds good examples of the two-dimensional Ising model.
100 citations
TL;DR: It was concluded that these strains required a low oxidation-reduction potential for growth and fermentation, and turned out to inactivate specifically fructose-6-phosphate phosphoketolase, a key enzyme of the fermentation pathway of bifidobacteria.
Abstract: The degree of sensitivity of twelve Bifidobacterium (Lactobacillus bifidus) strains to O2 was determined by measuring the size of the inhibition zones obtained when the bacteria were grown in deep agar cultures under air, and by measuring growth in aerated cultures. The size of the inhibition zones varied from 1 to 23 mm. Growth in aerated cultures differed markedly for the strains investigated. No strain grew on agar plates under aerobic conditions.
91 citations
TL;DR: Application of the linearising properties of auxiliary signals added to the sinusoidal stimulus resulted in the determination of a functional sequence of the events in the retina and also of the characteristics of some of these processes.
TL;DR: In this article, the second excited singlet state of pyrene and 3,4-benzpyrene in the vapour phase has been observed and the effect of inert gas, temperature and excitation frequency has been investigated.
TL;DR: Prteus mirabilis can form four reductases after anaerobic growth: nitrate reductase A, chlorate reduct enzyme C, thiosulfate reduction and tetrathionate reduction as discussed by the authors.
Abstract: Prteus mirabilis can form four reductases after anaerobic growth: nitrate reductase A, chlorate reductase C, thiosulfate reductase and tetrathionate reductase The last three enzymes are formed constitutively Nitrate reductase is formed only after growth in the presence of nitrate, which causes repression of the formation of thiosulfate reductase, chlorate reductase C, tetrathionate reductase and hydrogenase Formic dehydrogenase assayed with methylene blue as hydrogen acceptor is formed under all conditions Two groups of chlorate resistant mutants were obtained One group does not form the reductases and formic dehydrogenase The second group does not form nitrate reductase, chlorate reductase and hydrogenase, but forms formic dehydrogenase and small amounts of formic hydrogenlyase after growth without hydrogen acceptor or after growth in the presence of thiosulfate or tetrathionate Nitrate prevents the formation of formic dehydrogenase, thiosulfate reductase and tetrathionate reductase in this group of mutants Only after growth with thiosulfate or tetrathionate the reductases for these compounds are formed Anaerobic growth of the wild type in complex medium without a fermentable carbon source is strongly stimulated by the presence of nitrate Tetrathionate and thiosulfate have no effect at all or only a small effect The results show that in the presence of tetrathionate or thiosulfate the bacterial metabolism is fully anaerobic, as these cells also contain formic hydrogenlyase
TL;DR: Experimental subarachnoid haemorrhage in rabbits induces changes in cardiac rate and rhythm comparable with those observed in human patients with intracranial haem orrhage, suggested by the blocking effect of propranolol and cocaine.
Abstract: Experimental subarachnoid haemorrhage in rabbits induces changes in cardiac rate and rhythm comparable with those observed in human patients with intracranial haemorrhage. Biochemical and histological signs of myocardial damage were absent. A causal relationship between tissue catecholamine changes and the electrocardiographic disturbances is suggested by the blocking effect of propranolol and cocaine.
TL;DR: The distribution of malonyl-CoA decarboxylase in fractions obtained by treatment of rat-liver mitochondria with digitonin follows the same pattern as ‘matris’ enzymes such as malate dehydrogen enzyme and glutamate dehydrogenase.
TL;DR: The kinetics of the reaction catalysed by succinate dehydrogenase have been studied and support a mechanism in which the product of reaction between enzyme and substrate is oxidized by electron acceptor before dissociation of the product, fumarate, from the enzyme.
TL;DR: It is shown that the average number of single- or double-strand breaks per molecule can be calculated from the sedimentation distance corresponding to the maximum of the distribution of broken DNA in the gradient.
TL;DR: Conjugation experiments showed the presence of a strong linkage between thechl andgal markers of the bacterial chromosome, and deletion mapping the gene ordernic A aro G gal bio chl D uvr B chl A was found.
Abstract: S.typhimurium can form nitrate reductase A, chlorate reductase C, thiosulfate reductase, tetrathionate reductase and formic dehydrogenase. None of these enzymes are formed in chlorate-resistant mutants. Conjugation experiments showed the presence of a strong linkage between thechl andgal markers of the bacterial chromosome. By deletion mapping the gene ordernic A aro G gal bio chl D uvr B chl A was found. Strains with deletions terminating betweenbio anduvr B or betweenuvr B andchl A have a number of aberrant properties. Though resistant against chlorate they reduce nitrate and form gas. After growth with nitrate they form less nitrate reductase than the wild type which may explain the resistance against chlorate. After growth with thiosulfate they form small amounts of thiosulfate reductase and chlorate reductase C. In crosses between anE.coli Hfrchl
+ strain and aS.typhimurium chl A strain recombinants were obtained, forming nitrate reductase A and chlorate reductase C. These recombinants do not form gas, which indicates that thechl
+ gene fromE.coli does not function normally inS.typhimurium.
TL;DR: Hphal wall preparations of Apodachlya branchynema, Dictyuchus sterile, Pythium sp.
TL;DR: Almost 70% of the prey of adult females of Pardosa amentata consists of Diptera, and during warm sunny days adult females feed more actively in the morning than in the afternoon.
Abstract: Almost 70% of the prey of adult females of Pardosa amentata consists of Diptera. During warm sunny days adult females feed more actively in the morning than in the afternoon. The duration of feeding is directly proportional to the weight of the prey. Adult females, on warm sunny days, kill, on average, just over one prey organism (approximately 3.5 mg live weight) per day.
TL;DR: In this paper, a pollen diagram is presented from a crater lake in central western Italy, showing fluctuations between a steppe and a more closed vegetation, probably covering the period from the Early Wurm Brorup Interstadial to Late Holocene Subboreal times.
TL;DR: Serum samples from 116 women taken at different times during and after the first pregnancy were tested for the presence of cytotoxic lcucocytc antibodies against the husbands' Ieucocytes.
Abstract: Summary. Serum samples from 116 women taken at different times during and after the first pregnancy were tested for the presence of cytotoxic lcucocytc antibodies against the husbands' Ieucocytes.
Antibodies were found in the serum of 15 women, 11 times during the pregnancy, and as early as at 24 weeks of gestation. All antibodies examined were IgG, even the earliest detectable antibodies. All sera contained antibodies against antigens common to granulocytes and lymphocytes; four sera also contained granulocytespecific antibodies and none lymphocyte-specific antibodies. No antibodies were demonstrable in any of the cord-blood and no granulo- or lympliopenia was seen in any of the children.
TL;DR: In three patients, all having as their only hemodynamic abnormality an elevated cardiac index at rest, ventricular echo beats could be elicited by ventricular premature beats induced during regular driving of the ventricle by the dual conducting system theory.
Abstract: In three patients, all having as their only hemodynamic abnormality an elevated cardiac index at rest, ventricular echo beats could be elicited by ventricular premature beats induced during regular driving of the ventricle. The occurrence of ventricular echo beats was in each case limited to a small delay-range of the premature beat. Retardation of retrograde conduction of the premature ventricular impulse to the atria appeared to be a necessary condition for the initiation of the echo phenomenon. One of the patients had retardation of antegrade A-V conduction of sinus and premature atrial beats. Atrial echo beats could be elicited in this case. The genesis of the ventricular echo phenomenon in these cases could be explained by the dual conducting system theory.
TL;DR: The observations contribute to the view that aggregation is the result of the coming together of individuals by undirected movements in sites with optimum humidity conditions, the specific movements being stimulated by drought.
Abstract: The formation and biological significance of aggregations of 6 species of surface dwelling Collembola of a coniferous forest soil were studied. The species are: Tomocerus minor (Lubbock), Lepidocyrtus cyaneus Tullberg, Orchesella cincta (Linne), Entomobrya nivalis (Linne), Isotomurus palustris (Muller) and Isotoma viridis Bourlet. All species showed a marked aggregation, but to a different degree and in different places, since the degree of aggregation of total Collembola appeared to be less than that of the individual species. The different degree of aggregation could not only in field studies, but also in laboratory experiments be related to the specific humidity preferences of the species. The stenohygric species Lepidocyrtus cyaneus, Isotoma viridis and Tomocerus minor appeared to have a high degree of aggregation, the euryhygric species Orchesella cincta and Entomobrya nivalis a lower one. The observations contribute to the view that aggregation is the result of the coming together of individuals by undirected movements in sites with optimum humidity conditions, the specific movements being stimulated by drought. The biological significance of aggregation is described as a protectional function (survival, moulting) and as a meeting system where reproductive behaviour is not yet developed.
TL;DR: The bacteriocin had little effect on resting cells as mentioned in this paper and showed no effect on RNA and DNA synthesis nor on respiration and fermentation in a leucine-deficient mutant.
Abstract: Enterobacter cloacae DF 13 produces a bacteriocin with killing action onKlebsiella edwardsii var.edwardsii. The degree of sensitivity to the bacteriocin depended on the medium in which the cells were grown and on the bacteriocin concentration used. An excess of bacteriocin (60 K.U./ml) arrested growth in about 60 min. Growth of bacteriocin-treated cultures could be restored by trypsin treatment. In Brain Heart Infusion cultures trypsin rapidly restored bacterial growth even after 60 min of bacteriocin treatment. However, in broth cultures and minimal medium cultures treated with bacteriocin for only 10 min, it took 4 to 5 hr before growth started again. The bacteriocin had little effect on resting cells. Broth-grown cells had about 280 and BHI-grown cells about 340 bacteriocin receptor sites. Bacteriocin DF 13 strongly inhibited protein synthesis after a lag-time of 15 to 60 min depending on the concentration used but had no effect on RNA and DNA synthesis nor on respiration and fermentation. The bacteriocin stimulated RNA synthesis in a leucine-deficient mutant after leucine deprivation.
TL;DR: The ultrastructure of the cells of the bursa copulatrix suggests the production of hydrolizing enzymes for the extracellular destruction of superfluous sperms obtained by copulation.
Abstract: The reproductive tract including the accessory sex glands of Biomphalaria glabrata have been studied by use of histochemical and electron microscope techniques.
TL;DR: NAD+ has no effect on the esterase activity, and the reduction of acetyl phosphate by NADH, and its arsenolysis, catalysed by the enzyme, require NAD+.
TL;DR: With the glucagon test, all patients with deficiency of the phosphorylase system showed a rise in blood glucose no different from that of normal children, so the statement of Sokal, Lowe, and Sarcione (1962) that a rapid rise of 50 mg./100 ml.
Abstract: The majority of patients with glycogenosis of the liver have one of three types of enzyme deficiency: deficiencyofglucose-6-phosphatase, ofthe debranching enzyme system, or of the phosphorylase system (Illingworth, 1961; Hers and Van Hoof, 1968). The severity of the disease and of its manifestations, such as hypoglycaemia and acidosis, is related to the underlying enzyme defect (van Creveld and Huijing, 1965). Treatment of patients with liver glycogenosis is dietary. The diet aims at reducing the effects of the metabolic disturbance and must vary with the type of enzyme defect (Fernandes and van de Kamer, 1965, 1968). It is important to start dietary management as early as possible, and therefore to diagnose the disease and the enzyme deficiency involved, at an early age. The definitive diagnostic procedure is assay of the enzymes, either in liver tissue orfor debranching enzyme and phosphorylase-in the leucocytes. But it would be useful to have available simpler tests to screen children in whom liver glycogen disease is suspected. Various screening procedures have been recommended, such as the epinephrine tolerance test (Howell, Ashton, and Wyngaarden, 1962), glucagon tolerance test (Hug, 1962; Lowe et al., 1962), and intravenous tolerance test with fructose (Hers, 1959) or galactose (Schwartz, Ashmore, and Renold, 1957). Ockerman (1967) has reviewed the application of these tests. In our experience, they often have drawbacks. With the glucagon test, all our patients with deficiency of the phosphorylase system showed a rise in blood glucose no different from that of normal children. Thus, the statement of Sokal, Lowe, and Sarcione (1962) that a rapid rise of 50 mg./100 ml. or more in blood glucose after intramuscular glucagon virtually rules out liver glycogen disease, does not hold for this group of patients. Moreover, the glucagon test is usually performed after prolonged fasting