Le gisement de Freiria de Rio Maior,Portugal, et sa faune de Mammiferes; Nouvelle espece de Rotundomys,consequences stratigraphiques

A new locality, close to Freiria de Rio Maior, provided a mammalian fauna associated with Charophytes, secds,Ostracods, Gastropods and Urodels. The most abundant remains correspond to a new species: Rotundomys freiriensis. This fauna has been dated as the Upper Vallesian base (MN 10), corresponding to the most recent level with small mammals found in the portuguese Miocene. Thus, the Freiria limestone succession is correlated to Cartaxo, Almoster, etc., limestones which are so developed in the Ribatejo area.     

Reflexions sur l'usage,en biologie,de la theorie de l'information

For living beings, information is as fundamental as matter or energy. In this paper we show: a) inadequacies of quantitative theories of information, b) how a qualitative analysis leads to a classification of information systems and to a modelling of intercellular communication. From a quantitative point of view, the application in biology of information theories borrowed from communication techniques proved to be disappointing. These theories ignore deliberately the significance of messages, and do not give any definition of information. They refer to quantities, based upon arbitrarily defined probabilistic events. Probability is subjective. The receiver of the message needs to have ‘meta-knowledge’ of the events. The quantity of information depends on language, coding, and arbitrary definition of disorder. The suggested objectivity is fallacious. In common language, the word ‘information’ is synonymous with knowledge of order. Following common sense a message (letters, coded signals, etc.) is information just in case it is interpretable, i.e.if it fits to a previously acquired meaning (the words of an available language, etc.). The consequence is that calculation of quantities in the sense of Shannon can be used for transmissions, but it is itself meaningless (has no significance). In linguistics and semantics, information is composed of a ‘signifier’, a physical medium (letters, coded signals, etc.), and a ‘signified’ or significance. The nature of information is complex. The laws of linguistics and semantics are valid not only at the human, organismic level, but also at the cellular and molecular level. The physiology of sensations gives us many examples for application of a concept of information An electromagnetic wave of 0,7% give us the sensation of a red colour. Sensations have no physical reality. They are purely subjective. At the cellular level communication operates by means of chemical messengers (first messengers), which generally do not penetrate the plasmic membrane. Specific captors operate as transductors: external factors are converted into secondary messengers (cyclic AMP, Ca ion, etc.). Sometimes, electric signals (like depolarization waves) may also play a part in the intercellular communication. Such processes are characterized by changes in a sequence of different molecules carried by a physical signal. What is transmitted is themeaning of the message (significance) which can be memorized by the cell, providing a possible following use. At the molecular level one can find also the processes of linguistic nature. We know that the significance of a word is changed with changing the order of letters (ADD→DAD, etc.). In the same way bases C and U are coding for serine (UCC), leucine (CUC) or proline (CCU). Here, amino-acids express the significance. In spite of the fact that this key-lock mechanism may explain many reactions, the examples prove that other elements are necessary for understanding the information. The living cell is the receiver. The message actualizes only previously learned and memorized significances or actions (trigger effect). Significance is not an emergent property of the shape of the message. It depends on the receiver and the transmitter. A word can have more than one meaning. Similarly, a messenger can order different physiological responses: muscular tension, hormonal secretion, etc.. Thus a chemical messenger is a signal which is identified and interpreted by the receiver, depending upon specific languages and previous learning. These views are in harmony with immunological and Jerne's theory (of idiotypical net). The above mentioned considerations led the author to propose thetheory of data transfer, which takes into account significance. In this theory the quantity of information is the product of the probabilistic recognition of message and the value of significance as determined by its semantic level. (See: Acta biotheoretica vol. 41 No 1/2 June 1993.) The complex nature of information asks to propose a qualitative classification with respect to thematerial support and thesignificance.

1. The material support may be linear in time (sequential reading, ADN translation)-The material support may be referred to non-temporally (drawings, logos, holograms) (Reading is instantaneous)-The material support may be in circulation, or in stock.
2. The significance may be local (tissues, organs) or general (organisms). Asignificance may be a command to be executed (imperative, conditional order) or knowledge to bememorized. The purpose of significance may be a coding for space (for morphology) or for time (ontogeny, ageing).

Conclusion: Information cannot any longer be regarded as an object. Its nature is complex, at all levels of a living being. At the molecular level to memorize an information by modification of a molecule is comparable with writing words on a diary. The key-lock process does not suppress the question of the interpretation, i.e. relations existing between the shape of a microscopic element as a molecule, and its macroscopic effect, as an antenna or a leg. There are still many unclear points in these relations, e.g. the sweet taste of molecules of tomatine and monelline. The abstract nature of significance which at the human level is concerned to mental processes, is not only a philosophical problem. In fact, there is a hypothesis based on quantum mechanics which allows to consider a physical nature of significance. In any case, the important conclusion is that significance in bio-information must be considered in relation to the message-receiver. The receiver must no longer be considered a passive one. The qualitative classification of information will allow an understanding of circulation of information in organisms and between cells.     

Etude comparative de la densite de groupes de poissons cavernicoles et epiges (characidae,cyprinidae, clariidae)

The group density of four species of cave fishes (Caecobarbus geertsi, Barbopsis devecchii, Astyanax gen. and Uegitglanis zammaranoi) and of two taxonomically related epigean species (Barbus conchonius and Hyphessobricon scholzei) was measured tridimensionally in an experimental aquarium, using a video recorder and a mirror inclined at 45° placed on top of the aquarium. The experiments were conducted in dim red light. The illumination was continuous in the case of cave fishes. For the epigean forms a 12/12 LD cycle was superimposed using dim achromatic sources. The relative positions of individuals within their own specific group were registered hourly during a week (168 h). Results show that in cave forms, the mean density of groups falls within the theoretical limits of random distribution values in all cases, whereas epigean species display a non-random aggregation tendency.     

Manifestation et Mode de Conservation de Leveillula taurica, Agent de l'Oïdium de la Tomate au Maroc

Manifestation and conservation of Leveillula taurica on tomatoes in Morocco Powdery mildew of tomato, caused by Leveillula taurica, was considered a minor disease until 1978 when serious outbreaks occurred. These outbreaks coincided with periods of a draught and the introduction of new hybrids from Europe. The pathogen infects a variety of plants, including eleven cultivated and five wild species. Infections of tomato plants were obtained by isolates collected from cultivated plants (Cynara cardunculus, Cicerarietinum, Medicago sativa, Capsicum annuum, Tropaeolum majus) and wild species (Chenopodium ambrosioides, Sonchus asper, Oxalis cemua, Urtica urens).     

Heminautilus sanctaecrucis,nouvelle espece de nautiloïde cretace

A new interpretation of the J.F. Pictet et G. Campiche's Nautilus lallierianus is here proposed. Their specimen canbe separated from Heminautilus lallierianus (d'ORB.) and Heminautilus saxbii (MORRIS). The new designation attributed is Heminautilus sanctaecrucis.     

Activite ovarienne de Tetrastichus atriclavus (Chalcidien, Eulophide). Effets de l'accouplement et de la presence de l'hote

Résumé Tetrastichus atriclavus, Eulophide de zone tropicale, s'attaque aux chrysalides de divers Lépidoptères. Il est élevé au laboratoire sur un hôte de remplacement: Galleria mellonella (Pyralidae), à 26°5 et à la photopériode 18 h (L) / 6 h (D).Dans ces conditions, l'accouplement a peu d'influence sur l'activité de ponte: la différence entre la fécondité des femelles vierges et celle des femelles accouplées n'est pas significative. De plus, les femelles vierges ont un fonctionnement ovarien comparable à celui des femelles accouplées.La fécondité est maximale en présence continue de l'hôte. L'absence d'hôte entraîne des rétentions, sans résorption. Lorsque l'hôte est introduit plusieurs jours après l'émergence du parasite, la capacité de ponte de ce dernier diminue. La diminution est d'autant plus grande que le temps de privation est plus long. Un grand nombre d'ufs est pondu immédiatement après l'introduction de l'hôte. Si le temps de privation est inférieur ou égal à 10 jours, on assiste, après la ponte massive du premier jour, à une reprise de l'activité du germarium.

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Summary Tetrastichus atriclavus, an Eulophid which is found in tropical regions, parasitises pupae of several Lepidoptera. It is reared in the laboratory on Galleria mellonella pupae, at 26.5° and with the photoperiod 18 h (L)/6 h (D).Mating has little influence on oviposition: there is no significant difference between the fecundity of virgin and mated females. Fecundity is highest when the host is always present. When the host is provided several days after the emergence of the parasite, the number of eggs laid is lower, the decrease being higher as the absence of host is longer. Many eggs are laid just after the host is provided. If the absence of host is 10 days or less, the germarium becomes active again after the heavy oviposition on the first day.

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Nous dédions ce travail à la mémoire du Professeur J. R. Le Berre, avec notre hommage reconnaissant et ému.     

Sur le mode de croissance de Nuia,algue incertae sedis

The authors recall some data concerning the distribution, the ecology and the taxonomy of Nuia and describe in detail its mode of growth, distinguished by 6 different growth-forms.     

Intervention des sialo-glycoconjugués dans les réactions histochimiques de Diezel,de Shear et Pearse de métachromasie,de capture de fer et du bleu Alcian

Résumé La sensibilité de ces techniques vis à vis de l'acide sialique fut précisée. Pour cela, elles furent appliquées à des coupes de différents tissus frais de Rat et de Mouton effectuées au cryostat, avant et après hydrolyse enzymatique. Le colorant métachromatique bleu de méthylène, employé à différents pH, fut appliqué à des coupes traitées par la méthylation, la saponification, et les hydrolyses chimique et enzymatique de l'acide sialique, puis son absorption fut mesurée à l'électrophotomètre. Seuls, les tissus très riches en sialo-glycoconjugués donnèrent des résultats satisfaisants avec la métachromasie et la méthode de capture de fer et du bleu Alcian.

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Interference of sialo-glycoconjugates in the histochemical reactions of Diezel, Shear and Pearse, metachromasia, iron capture and Alcian blue

Summary The sensitivity of these techniques with respect to sialic acid were determined. For this, the methods of Diezel, Shear and Pearse, iron capture and Alcian blue were applied to sections of fresh tissues of the rat and sheep prepared on the cryostat-submaxillary gland, liver and brain-before and after the selective elimination of sialic acid by neuraminidase. The metachromatic colorimetric reagent methylene blue, used at different pH values (2 to 8) was applied to sections treated by methylation, saponification and chemical hydrolysis by sulphuric acid and enzymatically, then the absorption was measured on an electrophotometer. The results obtained with the methods of Diezel and of Shear and Pearse respectively were negative and not very convincing. With the other techniques only the tissues very rich in sialo-glycoconjugates gave satisfactory results. Moreover, the measurement of variation in the absorption of methylene blue permitted determination of the different acid compositions of these tissues.

     

Structure de la paroi de Aremoricanium rigaudae Deunff, 1955 (Acritarche,Ordovicien)

The wall of Aremoricanium rigaudaeDeunff, 1955, type-species by original designation of the genus AremoricaniumDeunff, 1955, is composed of two layers: the internal one has a circular opening while the second is the only one which develops the processes and a tubular expansion.