Showing papers by "University of Bologna published in 1970"
165 citations
TL;DR: The metabolism of long-chain fatty acids in the rumen discusses the importance of veterinary problems in stimulating new interest in biochemical processes that might improve foods of animal origin and, thus, human nutrition.
Abstract: Publisher Summary This chapter discusses the metabolism of long-chain fatty acids in the rumen. The studies described in the chapter reveal the importance of veterinary problems in stimulating new interest in biochemical processes that might improve foods of animal origin and, thus, human nutrition. They have contributed to one of the most interesting areas of biochemical studies: the molecular basis of evolution. They have allowed the discovery of living biochemical fossils and have helped to elucidate the mechanisms of branched fatty acid biosynthesis and unsaturated fatty acid biohydrogenation. Studies on the origin of petroleum in association with studies on biological evolution show that branched-chain hydrocarbon structures derive from the corresponding fatty acid molecules. In fatty acid biohydrogenation, the enzyme responsible for the disappearance of a π bond probably represents a vestige, whose deep biological meaning is now hidden in the rumen, of the mechanisms of energy transformations of primitive organisms, when there was no oxygen in the atmosphere, at the beginning of life on earth.
114 citations
TL;DR: The existence of multiple forms or “activities” of RNA polymerase in rat liver nuclei has been postulated, and cw-amanitin could be a useful tool to estimate by difference the activity of polymerase I and II without extracting them from nuclei.
57 citations
TL;DR: In this paper, a model consisting of a system of ordinary first-order differential equations each representing water level as a function of thime in one of the some 300 meshes into which the whole area can be divided.
Abstract: It has been proposed to control the flood which periodically inundates 50,000 sq km in the Lower Basin of the Mekong River in Cambodia and South Vietnam by means of a barrage across the Tonle Sap. This would transform the Great Lake of Cambodia into a 72 billion cu m reservoir. The used model consist of a system of ordinary first-order differential equations each representing water level as a function of thime in one of the some 300 meshes into which the whole area can be divided. Exchange relations between cells are based either on Saint Venant’s dynamic equations or on the weir type exchange laws, inertia terms being ignored in both cases due to the very small velocity of flood propagation. Boundary conditions are represented by about 50 additional imaginary cells. A flood lasting 3.5 months corresponds to about 120 computation cycles with a time increment varying between 6 hrs. and 48 hrs. It requires about 1 hr of computer time. Printout is done by means of the IBM 1401.
56 citations
TL;DR: It is concluded that synthesis and translocation of such compounds during germination can be compared with an analogous pattern of RNA and protein changes.
Abstract: SUMMARY
The distribution and changes in spermine and spermidine during the germination and seedling growth of bean (Phaseolus vulgaris) were investigated. The results show in vivo a substantial parallelism between RNA and protein changes and polyamine changes during germination. Spermine and spermidine diminish in the cotyledons and increase in the shoots especially the epicotyls. The data concerning in vitro cultures of isolated cotyledons and embryos show that there is a dc novo synthesis of spermine and spermidine in the seedlings particularly in the light. Although the greater part of the polyamines are translocated from cotyledons to embryo and afterwards into the different parts of the growing seedling, some is degraded. It is concluded that synthesis and translocation of such compounds during germination can be compared with an analogous pattern of RNA and protein changes.
55 citations
TL;DR: The three dimensional structure of adenosine triphosphate in the hydrated disodium salt is reported to a resolution of 0.9 Å.
Abstract: The three dimensional structure of adenosine triphosphate in the hydrated disodium salt is reported to a resolution of 0.9 A.
52 citations
TL;DR: The chick embryo was chosen because in previous experiments spermine and spermidine could not be detected in the yolk of unincubated eggs, whereas the presence of both in the early stage of embryo development indicated an en novo synthesis.
Abstract: The fertilized chick egg is a highly organized system with all the properties for a normal differentiation and development. The events during the embryo development are characterized by a large series of complex and definite chemical reactions, all having a temporal sequence and regulated by the trinomial: DNA -+ RNA --+ proteins. This complex biological system is useful in studying the molecular mechanisms responsible for cellular growth and differentiation. Nevertheless, other embryos such as those of amphibians are more suitable for studying the unfertilized egg and the very early stages of development immediately after fertilization. There are two obvious variables during embryonic development of the chick: on the one hand there is an increase in the amount of living tissue, and on the other, a proportional depletion in the amount of available food material. The chemical growth of the embryo expressed by the actual weight or increase in weight, plotted against time, yields a characteristic S-line. This is common of many other organisms at different phylogenetic levels, and indicates that the chick embryo grows more rapidly during the second half of its development. Taking into consideration the percentage of growth rate of wet weight of the chick embryo (see FIGURE l ) , there is a rapid fall initially from very high to low values. The genera1 opinion of embryologists is that the decrease in the specific rate of growth is due to the slowing down of the biosynthetic processes and of the mitotic index.' The embryo can be an advantageous system for studying the polyamine role in cellular metabolism, considering the relationship existing between these substances and cellular growth as has been shown in microorganism^,^^^ in cultured cells,: in animal and vegetable tissues '3 and in regenerating liver.s The chick embryo was chosen because in previous experiments spermine and spermidine could not be detected in the yolk of unincubated eggs, whereas the presence of both in the early stage of embryo development indicated an en novo synthesis. The presence of polyamines in embryonic tissues and in those in which we observe a higher protein synthesis, such as pancreas, liver, and prostate gland, led us to suspect a close relationship between these polycationic compounds and nucleic acid metabolism. The first observation concerns the parallel behavior of both polyamine and nucleic acid concentrations during the successive stages of chick embryo development. The maximum levels of polyamines correspond to the nucleic acid ones. It is interesting to note that by inhibiting the amino oxidase activities, the polyamine concentration increased rapidly followed by a parallel increase
50 citations
TL;DR: It is concluded that the binding of phospholipids to the proteins of the mitochondrial membranes is largely hydrophobic in nature.
50 citations
TL;DR: A good correlation can be found between the ultraviolet spectra of such compounds and their activity which seems to depend on the ability of active compounds to exist in an extensively conjugated structure and to form hydrogen bonds.
Abstract: 1. New halogenated 1,4-naphthoquinones were synthesized and together with other known 1,4-naphthoquinones, were screened for antibacterial activity by a turbidimetric method, and for antifungal activity by the diffusion method on agar plates.
2. The half-wave potentials and the influence on the oxidative phosphorylation of some of these compounds were determined.
3. 2-chloro-3,2′-chloro-ethyl-1,4-naphthoquinone (half-wave potential=-187 mV) was the most active compound, completely inhibiting cell respiration.
4. While the natural active naphthoquinones, vitamin K and ubiquinones, possess, as substituent, the electron repelling methyl group, the microbiologically active 1,4-naphthoquinones are substituted, in the quinone moiety, with electron attracting groups such as OH or Cl.
5. The half-wave potentials can give only an initial indication of the activity of the compounds studied; a good correlation, on the contrary, can be found between the ultraviolet spectra of such compounds and their activity which seems to depend on the ability of active compounds to exist in an extensively conjugated structure and to form hydrogen bonds.
45 citations
TL;DR: In this article, the elastic and inelastic interactions of positive kaons with protons were observed in a bubble chamber experiment, and the authors described a phase shift analysis of the elastic channel.
41 citations
TL;DR: The reversible light-induced activation in vivo of NADP-dependent glyceraldehyde-3-phosphate dehydrogenase was clearly shown to be independent from net protein synthesis, and neither the υmax of NAD+ and NADH linked activities, nor any of the apparent Km values of substrates are significantly affected.
TL;DR: The addition of a NADH-reoxidizing system in the assay of these enzyme activities is proposed, and rat liver xanthine oxidase type O (oxygen-dependent) is not affected by NADH.
Abstract: 1. Rat liver xanthine oxidase type D (NAD+-dependent) and chick liver xanthine oxidase are inhibited by NADH, which competes with NAD+. 2. The addition of a NADH-reoxidizing system in the assay of these enzyme activities is proposed. 3. Rat liver xanthine oxidase type O (oxygen-dependent) is not affected by NADH.
TL;DR: Chitosan, a chelating polymer, has been used to collect traces of transition elements from salt solutions and sea water by column chromatography as mentioned in this paper, and it can be favorably compared with the Chelating resin Chelex®, and it is proposed as a chelation chromatographic support suitable for pollution detection survey and abatement, for waste water purification and recovery of trace metal ions for analytical purposes.
TL;DR: The earliest demonstrable ovent in cells infected by FV-3 is a marked depression of cellular RNA synthesis, within 1 h of infection, and the characteristics of virus replication have been reviewed by Granoff.
Abstract: FROG virus (FV-3) is one of a group of polyhedral DNA-containing viruses, isolated from normal, tumour and diseased tissues of a variety of amphibia, which replicate within the cytoplasm of infected cells1. FV-3 multiplies at 12° to 31° C, with a distinctive cytopathic effect, in cell cultures from both poikilothermic and homothermic (including human) vertebrates1,2. The properties of the virion and the characteristics of virus replication have been reviewed by Granoff1. The earliest demonstrable ovent in cells infected by FV-3 is a marked depression of cellular RNA synthesis, within 1 h of infection1,3.
TL;DR: In this article, the authors concluded that autochthonous histoplasmosis is present but rare in Europe, after reviewing the reports ofHistoplasma capsulatum in man, animal and soil, and the results of histoplasmin sensitivity tests in Europe.
Abstract: After reviewing the reports ofHistoplasma capsulatum in man, animal and soil, and the results of histoplasmin sensitivity tests in Europe, we have concluded that autochthonous histoplasmosis is present but rare in Europe.
TL;DR: It is concluded that primary afferents from the superior oblique muscle enter the brain stem through the trigeminal ophthalmic branch and have their perikaria in the semilunar ganglion.
TL;DR: In this paper, a differentially pumped specimen stage is described which allows thin film deposition studies to be carried out inside an electron microscope, and it is shown that meaningful studies of thin film growth of reactive materials are now possible.
Abstract: A differentially pumped specimen stage is described which allows thin film deposition studies to be carried out inside an electron microscope. The pressure in the specimen vicinity can be reduced to about 10 ntorr after 16 hours pumping, and it is shown that meaningful studies of thin film growth of reactive materials are now possible.
TL;DR: Representatives of the species of the genus Bifidobacterium isolated from bovine rumen, intestinal content of honey bees and pig feces were studied for their deoxyribonucleic acid similarities with DNA-DNA filter hybridization-competition experiments.
Abstract: Representatives of the species of the genus Bifidobacterium isolated from bovine rumen, intestinal content of honey bees and pig feces were studied for their deoxyribonucleic acid similarities with DNA-DNA filter hybridization-competition experiments. The species were: B. asteroides, B. indicum and B. coryneforme from honey bees; B. ruminale and B. globosum from rumen; B. suis from pig feces; Mitsuoka's species B. thermophilum and B. pseudolongum. Strains of B. bifidum, B. infantis, B. longum and B. breve from human sources were included in some comparative experiments. The group of bacteria investigated is largely heterogeneous: virtually no homology exists among the species from rumen and pig feces; the species or types from bees, although unrelated with rumen and pig types, share with these a significant portion of the genome; the competitor DNA's from human strains did not at all react with any of the homologous systems. The annealing reaction was carried out under stringent conditions to ensure against mismatching of nucleotide sequences (70°C in Denhardt's reactive mixture). The separation within the genus Bifidobacterium of several specific entities is fully substantiated.
TL;DR: It is concluded that the interactions appear to be relevant to the interactions in the native membranes and that the bonds formed between protein and lipids must be primarily hydrophobic, although a contribution of polar forces to the binding cannot be excluded.
TL;DR: In this paper, the infrared spectra of gaseous, liquid and crystalline (CH 3 CO 2 O and (CD 3 CO) 2 O were studied and the possibility of a coexistence of two isomeric forms is dicussed and it is concluded that most probably only one form is present.
TL;DR: The reactivity of the protective agent, selenourea, towards the primary radicals of water radiolysis, OH, H and the hydrated electron, has been measured by the pulse-radiolysis technique and it is shown to be a charged complex involving two selenOUrea molecules.
Abstract: SummaryThe reactivity of the protective agent, selenourea, towards the primary radicals of water radiolysis, OH, H and the hydrated electron, has been measured by the pulse-radiolysis technique. The radical reactivity of the selenium-, sulphur- and oxygen-containing areas is compared with the radioprotective efficiencies of these compounds: the most efficient radical scavenger, selenourea, is the most efficient protective agent.Both the OH radical and the hydrogen atom give rise to the same radical species when reacting with selenourea. The radical formed by this reaction has a strong absorption band at 410 nm, and it is shown to be a charged complex involving two selenourea molecules. The formation and decay kinetics of this radical ion have been measured together with the association/dissociation constant of the complex. On a radical-scavenging mechanism, the ability of a secondary radical to form a complex may have some bearing on the protective efficiency of the parent compound.The selenourea system h...
TL;DR: In this article, cross sections of final states produced in K − n interactions at 3 GeV/c were presented, obtained in a 7 events/ub bubble chamber exposure with deuterium, compared with results from an earlier K − p exposure at the same incident K − momentum.
TL;DR: The low energy I = 3 2 K π elastic-scattering cross section was obtained from an analysis of the reaction K − n → pK − π − using the Chew-Low extrapolation method as discussed by the authors.
TL;DR: In this paper, the energy dependence of the first forbidden Fermi and Gamov Teller matrix elements was studied using sum rule techniques, which gave a simple tool for the evaluation of the SU(4) breaking effect.
TL;DR: A method of isolating large quantities of crystallized ribosomes from hypothermic chick embryos is described, and the isolated ribosome crystals maintain the same average dimensions and the same type of aggregations as those prepared in vivo.
TL;DR: In this paper, the dressing transformation is used to perform a mass renormalization of a neutral scalar free field in the Hamiltonian formalism, for arbitrary space dimension, and the resulting situation is analyzed by means of a Bogoliubov transformation.
Abstract: The method of the dressing transformation is used to perform a mass renormalization of a neutral scalar free field in the Hamiltonian formalism, for arbitrary space dimension. The resulting situation is analyzed by means of a Bogoliubov transformation, and seen to yield the expected results.
TL;DR: The RNA polymerase activity present in the cytoplasm of BHK cells infected with vaccinia virus is not affected by rifampicin or by alpha-amanitin.
Abstract: The RNA polymerase activity present in the cytoplasm of BHK cells infected with vaccinia virus is not affected by rifampicin or by α-amanitin
TL;DR: In this article, the energy loss of protons channelled along the [001] direction in 500 A thick gold is analyzed as a function of emergence angle. But the results of this paper are limited to the case of a single channel.
Abstract: The energy loss of protons channelled along the [001] direction in 500 A thick gold is analysed as a function of emergence angle. For a given emergence angle, the energy loss can be related to a particular path along the channel and, by applying Poisson's equation to the interatomic potential, to the local electron density. The small thickness of the samples used in the present investigation, compared to prior investigations, allows a relatively simpler and more unequivocal interpretation of the experimental data than previously possible. The relative variation in the stopping power due to channelling turns out to be much smaller than the variation in the local electron density, in satisfactory agreement with recent theoretical expectations (Bonsignori and Desalvo 1969). Also, our measurements distinguish between not too different approximations to the interatomic potential : Lindhard's potential yields agreement with experiment and Nielsen's does not.