Dissecando o GEN

In thee present paper the classical concept of the corpuscular gene is dissected out in order to show the inconsistency of some genetical and cytological explanations based on it. The author begins by asking how do the genes perform their specific functions. Genetists say that colour in plants is sometimes due to the presence in the cytoplam of epidermal cells of an organic complex belonging to the anthocyanins and that this complex is produced by genes. The author then asks how can a gene produce an anthocyanin ? In accordance to Haldane's view the first product of a gene may be a free copy of the gene itself which is abandoned to the nucleus and then to the cytoplasm where it enters into reaction with other gene products. If, thus, the different substances which react in the cell for preparing the characters of the organism are copies of the genes then the chromosome must be very extravagant a thing : chain of the most diverse and heterogeneous substances (the genes) like agglutinins, precipitins, antibodies, hormones, erzyms, coenzyms, proteins, hydrocarbons, acids, bases, salts, water soluble and insoluble substances ! It would be very extrange that so a lot of chemical genes should not react with each other. remaining on the contrary, indefinitely the same in spite of the possibility of approaching and touching due to the stato of extreme distension of the chromosomes mouving within the fluid medium of the resting nucleus. If a given medium becomes acid in virtue of the presence of a free copy of an acid gene, then gene and character must be essentially the same thing and the difference between genotype and phenotype disappears, epigenesis gives up its place to preformation, and genetics goes back to its most remote beginnings. The author discusses the complete lack of arguments in support of the view that genes are corpuscular entities. To show the emharracing situation of the genetist who defends the idea of corpuscular genes, Dobzhansky's (1944) assertions that "Discrete entities like genes may be integrated into systems, the chromosomes, functioning as such. The existence of organs and tissues does not preclude their cellular organization" are discussed. In the opinion of the present writer, affirmations as such abrogate one of the most important characteristics of the genes, that is, their functional independence. Indeed, if the genes are independent, each one being capable of passing through mutational alterations or separating from its neighbours without changing them as Dobzhansky says, then the chromosome, genetically speaking, does not constitute a system. If on the other hand, theh chromosome be really a system it will suffer, as such, the influence of the alteration or suppression of the elements integrating it, and in this case the genes cannot be independent. We have therefore to decide : either the chromosome is. a system and th genes are not independent, or the genes are independent and the chromosome is not a syntem. What cannot surely exist is a system (the chromosome) formed by independent organs (the genes), as Dobzhansky admits. The parallel made by Dobzhansky between chromosomes and tissues seems to the author to be inadequate because we cannot compare heterogeneous things like a chromosome considered as a system made up by different organs (the genes), with a tissue formed, as we know, by the same organs (the cells) represented many times. The writer considers the chromosome as a true system and therefore gives no credit to the genes as independent elements. Genetists explain position effects in the following way : The products elaborated by the genes react with each other or with substances previously formed in the cell by the action of other gene products. Supposing that of two neighbouring genes A and B, the former reacts with a certain substance of the cellular medium (X) giving a product C which will suffer the action, of the latter (B). it follows that if the gene changes its position to a place far apart from A, the product it elaborates will spend more time for entering into contact with the substance C resulting from the action of A upon X, whose concentration is greater in the proximities of A. In this condition another gene produtc may anticipate the product of B in reacting with C, the normal course of reactions being altered from this time up. Let we see how many incongruencies and contradictions exist in such an explanation. Firstly, it has been established by genetists that the reaction due.to gene activities are specific and develop in a definite order, so that, each reaction prepares the medium for the following. Therefore, if the medium C resulting from the action of A upon x is the specific medium for the activity of B, it follows that no other gene, in consequence of its specificity, can work in this medium. It is only after the interference of B, changing the medium, that a new gene may enter into action. Since the genotype has not been modified by the change of the place of the gene, it is evident that the unique result we have to attend is a little delay without seious consequence in the beginning of the reaction of the product of B With its specific substratum C. This delay would be largely compensated by a greater amount of the substance C which the product of B should found already prepared. Moreover, the explanation did not take into account the fact that the genes work in the resting nucleus and that in this stage the chromosomes, very long and thin, form a network plunged into the nuclear sap. in which they are surely not still, changing from cell to cell and In the same cell from time to time, the distance separating any two genes of the same chromosome or of different ones. The idea that the genes may react directly with each other and not by means of their products, would lead to the concept of Goidschmidt and Piza, in accordance to which the chromosomes function as wholes. Really, if a gene B, accustomed to work between A and C (as for instance in the chromosome ABCDEF), passes to function differently only because an inversion has transferred it to the neighbourhood of F (as in AEDOBF), the gene F must equally be changed since we cannot almH that, of two reacting genes, only one is modified The genes E and A will be altered in the same way due to the change of place-of the former. Assuming that any modification in a gene causes a compensatory modification in its neighbour in order to re-establich the equilibrium of the reactions, we conclude that all the genes are modified in consequence of an inversion. The same would happen by mutations. The transformation of B into B' would changeA and C into A' and C respectively. The latter, reacting withD would transform it into D' and soon the whole chromosome would be modified. A localized change would therefore transform a primitive whole T into a new one T', as Piza pretends. The attraction point-to-point by the chromosomes is denied by the nresent writer. Arguments and facts favouring the view that chromosomes attract one another as wholes are presented. A fact which in the opinion of the author compromises sereously the idea of specific attraction gene-to-gene is found inthe behavior of the mutated gene. As we know, in homozygosis, the spme gene is represented twice in corresponding loci of the chromosomes. A mutation in one of them, sometimes so strong that it is capable of changing one sex into the opposite one or even killing the individual, has, notwithstading that, no effect on the previously existing mutual attraction of the corresponding loci. It seems reasonable to conclude that, if the genes A and A attract one another specifically, the attraction will disappear in consequence of the mutation. But, as in heterozygosis the genes continue to attract in the same way as before, it follows that the attraction is not specific and therefore does not be a gene attribute. Since homologous genes attract one another whatever their constitution, how do we understand the lack cf attraction between non homologous genes or between the genes of the same chromosome ? Cnromosome pairing is considered as being submitted to the same principles which govern gametes copulation or conjugation of Ciliata. Modern researches on the mating types of Ciliata offer a solid ground for such an intepretation. Chromosomes conjugate like Ciliata of the same variety, but of different mating types. In a cell there are n different sorts of chromosomes comparable to the varieties of Ciliata of the same species which do not mate. Of each sort there are in the cell only two chromosomes belonging to different mating types (homologous chromosomes). The chromosomes which will conjugate (belonging to the same "variety" but to different "mating types") produce a gamone-like substance that promotes their union, being without action upon the other chromosomes. In this simple way a single substance brings forth the same result that in the case of point-to-point attraction would be reached through the cooperation of as many different substances as the genes present in the chromosome. The chromosomes like the Ciliata, divide many times before they conjugate. (Gonial chromosomes) Like the Ciliata, when they reach maturity, they copulate. (Cyte chromosomes). Again, like the Ciliata which aggregate into clumps before mating, the chrorrasrmes join together in one side of the nucleus before pairing. (.Synizesis). Like the Ciliata which come out from the clumps paired two by two, the chromosomes leave the synizesis knot also in pairs. (Pachytene) The chromosomes, like the Ciliata, begin pairing at any part of their body. After some time the latter adjust their mouths, the former their kinetochores. During conjugation the Ciliata as well as the chromosomes exchange parts. Finally, the ones as the others separate to initiate a new cycle of divisions. It seems to the author that the analogies are to many to be overlooked. When two chemical compounds react with one another, both are transformed and new products appear at the and of the reaction. In the reaction in which the protoplasm takes place, a sharp difference is to be noted. The protoplasm, contrarily to what happens with the chemical substances, does not enter directly into reaction, but by means of products of its physiological activities. More than that while the compounds with Wich it reacts are changed, it preserves indefinitely its constitution. Here is one of the most important differences in the behavior of living and lifeless matter. Genes, accordingly, do not alter their constitution when they enter into reaction. Genetists contradict themselves when they affirm, on the one hand, that genes are entities which maintain indefinitely their chemical composition, and on the other hand, that mutation is a change in the chemica composition of the genes. They are thus conferring to the genes properties of the living and the lifeless substances. The protoplasm, as we know, without changing its composition, can synthesize different kinds of compounds as enzyms, hormones, and the like. A mutation, in the opinion of the writer would then be a new property acquired by the protoplasm without altering its chemical composition. With regard to the activities of the enzyms In the cells, the author writes : Due to the specificity of the enzyms we have that what determines the order in which they will enter into play is the chemical composition of the substances appearing in the protoplasm. Suppose that a nucleoproteln comes in relation to a protoplasm in which the following enzyms are present: a protease which breaks the nucleoproteln into protein and nucleic acid; a polynucleotidase which fragments the nucleic acid into nucleotids; a nucleotidase which decomposes the nucleotids into nucleoids and phosphoric acid; and, finally, a nucleosidase which attacs the nucleosids with production of sugar and purin or pyramidin bases. Now, it is evident that none of the enzyms which act on the nucleic acid and its products can enter into activity before the decomposition of the nucleoproteln by the protease present in the medium takes place. Leikewise, the nucleosidase cannot works without the nucleotidase previously decomposing the nucleotids, neither the latter can act before the entering into activity of the polynucleotidase for liberating the nucleotids. The number of enzyms which may work at a time depends upon the substances present m the protoplasm. The start and the end of enzym activities, the direction of the reactions toward the decomposition or the synthesis of chemical compounds, the duration of the reactions, all are in the dependence respectively o fthe nature of the substances, of the end products being left in, or retired from the medium, and of the amount of material present. The velocity of the reaction is conditioned by different factors as temperature, pH of the medium, and others. Genetists fall again into contradiction when they say that genes act like enzyms, controlling the reactions in the cells. They do not remember that to cintroll a reaction means to mark its beginning, to determine its direction, to regulate its velocity, and to stop it Enzyms, as we have seen, enjoy none of these properties improperly attributed to them. If, therefore, genes work like enzyms, they do not controll reactions, being, on the contrary, controlled by substances and conditions present in the protoplasm. A gene, like en enzym, cannot go into play, in the absence of the substance to which it is specific. Tne genes are considered as having two roles in the organism one preparing the characters attributed to them and other, preparing the medium for the activities of other genes. At the first glance it seems that only the former is specific. But, if we consider that each gene acts only when the appropriated medium is prepared for it, it follows that the medium is as specific to the gene as the gene to the medium. The author concludes from the analysis of the manner in which genes perform their function, that all the genes work at the same time anywhere in the organism, and that every character results from the activities of all the genes. A gene does therefore not await for a given medium because it is always in the appropriated medium. If the substratum in which it opperates changes, its activity changes correspondingly. Genes are permanently at work. It is true that they attend for an adequate medium to develop a certain actvity. But this does not mean that it is resting while the required cellular environment is being prepared. It never rests. While attending for certain conditions, it opperates in the previous enes It passes from medium to medium, from activity to activity, without stopping anywhere. Genetists are acquainted with situations in which the attended results do not appear. To solve these situations they use to make appeal to the interference of other genes (modifiers, suppressors, activators, intensifiers, dilutors, a. s. o.), nothing else doing in this manner than displacing the problem. To make genetcal systems function genetists confer to their hypothetical entities truly miraculous faculties. To affirm as they do w'th so great a simplicity, that a gene produces an anthocyanin, an enzym, a hormone, or the like, is attribute to the gene activities that onlv very complex structures like cells or glands would be capable of producing Genetists try to avoid this difficulty advancing that the gene works in collaboration with all the other genes as well as with the cytoplasm. Of course, such an affirmation merely means that what works at each time is not the gene, but the whole cell. Consequently, if it is the whole cell which is at work in every situation, it follows that the complete set of genes are permanently in activity, their activity changing in accordance with the part of the organism in which they are working. Transplantation experiments carried out between creeper and normal fowl embryos are discussed in order to show that there is ro local gene action, at least in some cases in which genetists use to recognize such an action. The author thinks that the pleiotropism concept should be applied only to the effects and not to the causes. A pleiotropic gene would be one that in a single actuation upon a more primitive structure were capable of producing by means of secondary influences a multiple effect This definition, however, does not preclude localized gene action, only displacing it. But, if genetics goes back to the egg and puts in it the starting point for all events which in course of development finish by producing the visible characters of the organism, this will signify a great progress. From the analysis of the results of the study of the phenocopies the author concludes that agents other than genes being also capaole of determining the same characters as the genes, these entities lose much of their credit as the unique makers of the organism. Insisting about some points already discussed, the author lays once more stress upon the manner in which the genes exercise their activities, emphasizing that the complete set of genes works jointly in collaboration with the other elements of the cell, and that this work changes with development in the different parts of the organism. To defend this point of view the author starts fron the premiss that a nerve cell is different from a muscle cell. Taking this for granted the author continues saying that those cells have been differentiated as systems, that is all their parts have been changed during development. The nucleus of the nerve cell is therefore different from the nucleus of the muscle cell not only in shape, but also in function. Though fundamentally formed by th same parts, these cells differ integrally from one another by the specialization. Without losing anyone of its essenial properties the protoplasm differentiates itself into distinct kinds of cells, as the living beings differentiate into species. The modified cells within the organism are comparable to the modified organisms within the species. A nervo and a muscle cell of the same organism are therefore like two species originated from a common ancestor : integrally distinct. Like the cytoplasm, the nucleus of a nerve cell differs from the one of a muscle cell in all pecularities and accordingly, nerve cell chromosomes are different from muscle cell chromosomes. We cannot understand differentiation of a part only of a cell. The differentiation must be of the whole cell as a system. When a cell in the course of development becomes a nerve cell or a muscle cell , it undoubtedly acquires nerve cell or muscle cell cytoplasm and nucleus respectively. It is not admissible that the cytoplasm has been changed r.lone, the nucleus remaining the same in both kinds of cells. It is therefore legitimate to conclude that nerve ceil ha.s nerve cell chromosomes and muscle cell, muscle cell chromosomes. Consequently, the genes, representing as they do, specific functions of the chromossomes, are different in different sorts of cells. After having discussed the development of the Amphibian egg on the light of modern researches, the author says : We have seen till now that the development of the egg is almost finished and the larva about to become a free-swimming tadepole and, notwithstanding this, the genes have not yet entered with their specific work. If the haed and tail position is determined without the concourse of the genes; if dorso-ventrality and bilaterality of the embryo are not due to specific gene actions; if the unequal division of the blastula cells, the different speed with which the cells multiply in each hemisphere, and the differential repartition of the substances present in the cytoplasm, all this do not depend on genes; if gastrulation, neurulation. division of the embryo body into morphogenetic fields, definitive determination of primordia, and histological differentiation of the organism go on without the specific cooperation of the genes, it is the case of asking to what then the genes serve ? Based on the mechanism of plant galls formation by gall insects and on the manner in which organizers and their products exercise their activities in the developing organism, the author interprets gene action in the following way : The genes alter structures which have been formed without their specific intervention. Working in one substratum whose existence does not depend o nthem, the genes would be capable of modelling in it the particularities which make it characteristic for a given individual. Thus, the tegument of an animal, as a fundamental structure of the organism, is not due to gene action, but the presence or absence of hair, scales, tubercles, spines, the colour or any other particularities of the skin, may be decided by the genes. The organizer decides whether a primordium will be eye or gill. The details of these organs, however, are left to the genetic potentiality of the tissue which received the induction. For instance, Urodele mouth organizer induces Anura presumptive epidermis to develop into mouth. But, this mouth will be farhioned in the Anura manner. Finalizing the author presents his own concept of the genes. The genes are not independent material particles charged with specific activities, but specific functions of the whole chromosome. To say that a given chromosome has n genes means that this chromonome, in different circumstances, may exercise n distinct activities. Thus, under the influence of a leg evocator the chromosome, as whole, develops its "leg" activity, while wbitm the field of influence of an eye evocator it will develop its "eye" activity. Translocations, deficiencies and inversions will transform more or less deeply a whole into another one, This new whole may continue to produce the same activities it had formerly in addition to those wich may have been induced by the grafted fragment, may lose some functions or acquire entirely new properties, that is, properties that none of them had previously The theoretical possibility of the chromosomes acquiring new genetical properties in consequence of an exchange of parts postulated by the present writer has been experimentally confirmed by Dobzhansky, who verified that, when any two Drosophila pseudoobscura II - chromosomes exchange parts, the chossover chromosomes show new "synthetic" genetical effects.

Influência do cloro, sôbre a composição do caldo da cana de açúcar Co 290, aplicado no solo, na forma de cloreto de sódio

Considering the economic importance of the sugar industry among ourselves, the authors carried out a field experiment (Latin square) with Co 290 sugar cane, on a white sandy soil of Piracicaba, State of São Paulo, Brazil, applying NaCl in increasing rates (from 6.8 to 54.5 grams per plant), in order to study the effects of chlorides, on productivity and on the composition of juice. No toxic or stimulating effect was found, and there was no change in yield, in degree of purity of the juice, in general aspect of plants or in colour of leaves and culms. No difference was observed between potassium sulphate or chloride, as source of potash for sugar cane culture. Data collected and the literature cited suggest: (a) that the use of the variety Co 290 is indicated for soils rich in chlorine, such as the saline soils of the North-east and Atlantic Coast of Brazil; (b) that it is necessary to extend studies in Research Institutes and Agricultural Experiment Stations of the country to verify the behaviour of other varieties of sugar cane in the types of soils mentioned, especially with respect their yielding capacity. The authors are already planning such investigations.

Effects of 2-chloroetylphosphonic acid on ripening of mango

Mature fruits of mango 'Paheri' were treated immediately after harvest with ethefon at 0 - 250 - 500 - 1.000 and 2.000 ppm. Fruit ripening was accelerated by all treatments , the time to maturity being reduced from 48 to 72 hours, when compared with controls. Maturation was evaluated, by external colour of fruits, soluble solids and acid contents.

The aggregation of Chauliognathus species (Coleoptera, Cantharidae) and its possible role for coexistence and mimicry

The relative population sizes of a species complex of Chauliognathus are reported, as well as their spatial distribution associated with different patches of food plants. Field work was done at Fazenda Santa Isabel, municipality of Guaíba, State of Rio Grande do Sul, Brazil. The results suggest that two mechanisms account for the reduction in food competition among the species involved: one is asynchrony in the appearance of the species in the area, and the other is aggregation in different patches of food plants. Since the species here reported show a similar colour pattern (yellow-black) the possibility of the occurrence of serial mimicry in this complex of species is dicussed.

Incidência do reumatismo (febre reumática, reumatismo infecioso específico) no Rio de Janeiro

1 – A close inquiry into 6700 post mortem examinations reveals amongst them 589 cases of endocarditis which, as causa mortis, thus concur with an 8.82% score. 2 – As to their etiology, the endocarditis cases are classified in: Rheumatic E………………417cases or 6.22% of the necropsies; Syphilitic E……………….106 cases or 1.58% of the necropsies; Malignant E………………….66 cases or 0.98% of the necropsies . 3 – With the exception of the cases of syphilitic endocarditis, or aortic endocarditis connected with syphilitic changes, as well as of malignant (bacterial) endocarditis, 417 cases of rheumatic endocarditis are left which constitute 6.22% of the total amount of the post mortem examinations and 70.79% of the endocarditis cases. 4 – As to their anatomical location, the cases of rheumatic endocarditis are distributed as follows: Valvular E………..396 cases or 94.96% of the endocarditis cases; Mural E………..21 cases or 5.04% of the endocarditis cases; 5 – As to valvular changes, the following location was observed: Mitral E…………….156 cases or 39.39%; Aortic E……………120 cases or 30.30%; Tricuspid E…………10 cases or 2.51%; Pulmonary E…………2 cases or 0.50%; Mitral-aortic E……….88 cases or 22.22%; Mitral-tricuspid E………….10 cases or 2.51%; Mitral-tricuspid-aortic E…………9 cases or 2.27%; Mitral-tricuspid-pulmonary E………….1 cases or 0.25%. 6 – As to sex, 59.21% are males and 40.70% females. As regards mitral endocarditis, the incidence for both sexes is practically one and the same (49.55% of males and 50.47% of females), whilst as regards aortic endocarditis 74.16% of males and 26.84% of females are affected by. 7 – As to colour: White……..50.24% of the cases; Black……………28.50% of the cases; Brown……………21.25% of the cases. 8 – As to nationality: Brazilians…………81.86% of the cases; Aliens…………..18.13% of the cases. 9 – As to age: 0 to 10 years…………7 cases, 51 to 60 years……57 cases; 11 to 20 years……..33 cases, 61 to 70 years……51 cases; 21 to 30 years……..64 cases, 71 to 80 years……..21 cases; 31 to 40 years……..79 cases, 81 to 90 years……1 cases; 41 to 50 years…………58 cases, 91 to 100 years……..2 cases.

Notas de ixodologia: V - A propósito da validade de algumas espécies do gênero Amblyomma do continente americano (Acari: Ixodídoe)

a) The species Amblyomma tapiri Tonelli Rondelli, 1937 and Amblyomma finitimum Tonelli Rondelli, 1937 are synonymous with Amblyomma cajennense Fabricius, 1787. Both species are based in differences of size, colour, punctations and form of the dorsal shield, presence or absence of ventral plates, size, form and direction of the spine of coxa IV. Such differences prouved to be only variations frequently observed in large lots or in cultures of Amblyomma cajennense. The revalidation of Koch's species Amblyomma tenellum Koch, 1844 and Amblyomma mixtum Koch, 1844 proposed by TONELLI RONDELLI as also of Amblyomma sculptum Berlese, 1888 and Amblyomma versicolor Nuttal et Warburton, 1908 cannot be accepted by the same reasons. b) Amblyomma beccari Tonelli Rondelli, 1939 and Amblyomma latepunctatum Tonelli Rondelli, 1939 are cospecific with Amblyomma scalpturatum Neumann, 1899 the same being true for Amblyomma myrmecophagium Schulze, 1935 and for Amblyomma brasiliense var. guianense Floch et Abonnenc, 1940, as previously stated. c) Amblyomma tasquei Floch et Abonnenc, 1940 is a good species but synonym with Amblyomma romitii Tonelli Rondelli, 1939 which has priority. d) Amblyomma curruca Schulze, 1936 is a synonym of Amblyomma parvum Aragão, 1908. e) Amblyomma deminutivum Neumann, 1899 represents a variation of Amblyomma dissimile Koch, 1844, a species whose internal spine of coxa IV may be poorly developed or even absent. f) Amblyomma nigrum Tonelli Rondelli, 1939 prouved to be synonym with Amblyomma paccae Aragao, 1911 the type representing a blackish specimen of the later species. g) Amblyomma brimonti Neumann, 1913 is a synonym of Amblyomma humerale Koch, 1844.

Excreção urinária de 17-Cetoesteroides neutros no cavalo normal e no cavalo castrado

Total urinary neutral 17-steroids were determined in normal and in castrated horses. One liter of a 15-26 hours urine collection was hydrolysed by refluxing with 10% HC1 (v/v) for ten minutes and extracted with peroxyde-free ethyl ether. The extract was purified by washing with saturated NaHCO³ and KOH solutions. One half of the crude neutral fraction was fractionated with Girard's "T" reagent . The Zimmermann reaction was performed both in the ketonic and in the crude neutral extracts, using alcoholic 2.5N KOH and a 60 minutes period for the colour development in the dark. Optical density measuments were made in a grating Coleman Universal Spectrophotometer at 420 mµ and 520mµ; for the crude neutral fraction a colour correction equation was applied. The aliquot fraction used for colorimety was adjusted for keeping optical density measurements within the range 0.2 to 0.7. Androsterone (mp. 184-184.5°C) with an absorption maximum at 290.5 mµ (Beckman Model DU Spectrophotometer) was used as a reference standard. Table I, ilustrates the results obtained. At the 0.05 probability level there is a significant difference among castrated and normal group means (Fischer's "t" test.) when were used the data obtained from the ketonic fractions; in spite of the use of a colour correction applied for inespecific chromogens, the same results could not be obtained with the crude neutral fractions, Since Girard's reagent fractionation is generaly accepted as the best method for correcting the inespecific chromogen interference in the determination of the 17-ketosteroids by the Zimmermann reaction, we emphasize the value of the results obtained with the ketonic fractions. From these results it appears, as occurs in others mammals, that castrated horses show a lower level of urinary 17-ketosteroids excretion than the normal horses. The significance of the horse testis contribution for the neutral urinary steroid metabolites is discussed. Since horse urine has a low androgenic activity, the fractionation of the neutral 17-ketosteroids must be studied more accurately.

Ensaios de micologia contribuição para o conhecimento das Esporotricoses

The author describes the forms found in material obtained from a human lesion localized in the mouth. The patient was a farmer and the diagnosis unknown. The author found yeast forms, some germinating, resembling those found in the mycosis of LUTZ. It was Sporotricosis and only once, in 96 cases, has the author found these fungous forms in the suspected material. The cultures in Sabouraud glucose and in many other media were positive for Sporotrichum, resembling that described by BENEDEK in 1926 (variety?) principally by the reddish colour of some cultures. The author thinks there is, perhaps, a mutation influenced by the surroundings and the light in certain cultures and that the dark pigment is the dominant one. He considers that the pigment will not do for the differentiation of species and that it is, really, Sporotrichum Schencki-Beurmanni. The author calls attention to the question of diagnosis and studies separately, each of the elements in which his opinion is based, finding that only a macro and microscopic study of the cultures decides the question.

Terceira contribuicäo ao conhecimento do gênero Archytas Jaennicke, 1867: (Diptera, Tachinidae)

Twelve species of the genus Archytas Jennicke, 1867, eight of which described as new are studied and figured in detail. Definitions of the species are based mainly on characters of male genitalia. The male genital characters are the most significant for separation of the species and most demonstrative of their affinities. By examining a long series of species of this genus we came to the conclusion that the presence of one pair of median marginal bristles on the third abdominal tergite seems to be characteristic of the genus. This caracter apparently so important, is not however considered fundamental. The most significant example is found in Archytas lenkoi sp. n. and Archytas vexor Curran, 1928. In A. lenkoi we can find one or two pairs or thay may, less frquently, be absent. In A. vexor these bristles are lacking. The shape of the male copulatory apparatus of Jurinia nitidiventris Curran, 1928 refered to by CURRAN in his "Revision of Archytas", is not characteristic of any species of the group and so, is not considered in this paper. To help in the identification, the species studied here are divided into groups. The analis group" includes: A. apicifer (Walker, 1894), A. californiae (Walker, 1856), A. nivalis Curran, 1928, a. giacomellii (Blanchard, 1941), A. basifulvus (Walker, 1849), A. incasanus Townsend, 1912 and A. cirphis Curran, 1927. The identification of members of these group is extremely difficult owing both to their similarity in colour pattern and to their variability. They all have black testaceous or dark brown abdomen, the last segment pale or brownish pollinose; second segment without bristles; third with a pair of strong marginals, fourth and fifth with two rows of discals on apical third. The final determination often rests upon the structure of the male copulatory apparatus. Fortunately in this group, many of the forcipes superiores and palpi genitalium are strikingly different from one another. The "zikani group" includes: A. zikani sp. n., A seabrai sp. n., A. duckei sp. n. and A. vernalis Curran, 1928. This group may be characterized as follows: forcipes interiores absent; forcipes superiores strongly chitinized an dilated at anex. Within this group, the forcipes of. A. seabrai sp. n. do not present an aberrant form. The "dissimilis group" will be studied in forthcoming papers. The limits of the genus Archyta Jaen. are not as yet sharply difined, the evaluation of the significance of each character used in the definition remaining as most difficult problem. The distinction between Archytas and other related genera is very difficult, chiefly because it is based on variable characters. In this paper we place the genera Parafabricia Towsend, 1931, Itachytas Blanchard, 1940, Archynemochaeta Blanchard, 1941, Proarchytoides Blanchard, 1941 and Archytodejeania Blanchard, 1941 in the synonymy of Archytas Jaen. The detailed examination of the characters used in their definition, proved them to be fundamentally proposed on basis of chaetotasy, these characters alone being precarious, because of the considerabel intraspecifical variation. The type of the new species are in the Oswaldo Cruz Institute collection. Rio de Janeiro, Brazil, and paratypes in the collections of the followings institutions: Departamento de Zoologia da Secretaria de Agricultura do Estado de São Paulo; Instituto de Ecologia e Experimemtação Agrícolas; Departamento de Defesa Sanitária Vegetal; Campos Seabra collection; and Barbiellini collection.

Notas sôbre o gênero Colobogaster Solier, 1833, com a descrição de duas novas espécies da Região Amazônica: (Coleoptera, Buprestidae)

The study of materials belonging to several brazilian collections led us discover 2 new species of the genus Colobogaster which are here described. C. seabrai sp. n. seems to be related to C. puncticollis Waterhouse, 1882, from which it can be distinguished by: a) apical alitral tooth placed suturally, b) pronotum with 3 pairs of depressions, the 1st. pair transversal and conigous to the 2nd one, c) elitral suture brilliantgreen coloured but not the marginal edge, d) front without a horse-shoe shaped structure, e) pronotum with the discal region concolor. The structures of pronotum, the elitral and pronotal colour paterns and the genial morphology separate this one from other species of the genus. C. paraensis sp. n. is closely related to C. cupricollis Kerremans, 1897, but it is distinguished by the absence of depressions on the pronotum, by the elitral tooth placed suturally, by the abscence of humeral rip and by the general colour. Eleven other species were studied and their apical segment of the abdomen and scutellum were illustrated. It was also established the synonymy of C. ecuadoricus Obengerger, 1926.

A study of aspects of heterokaryosis in aspergillus nidulans

A series of studies have been undertaken to find cases in which heterokaryons show adaptative response to environmental change. Comparisons have also been made between the phenotypes of heterokaryons and corresponding heterozygotes. Unsuccessful attempts were made to produce heterokaryons, on complete medium, balanced by one previously-existing mutant and one newly-obtained slow-growing mutant. Adaptation was achieved in heterokaryons carrying different mutant alleles conferring resistance to: (a) acriflavine, (b) actidione and (c) p-fluorophenylalanine. Comparison with the heterozygote in case (a) suggested a highly localised action of the allele determining resistance. A similar comparison for (b) suggested a non-localised action. In cases (b) and (c) dosage effects were observed in the degree of resistance that the heterokaryons, compared with the corresponding heterozygotes, could achieve. In case (c) interaction of the resistance marker with a nutritional marker (nic8) has been investigated further and a new unteraction between nic8 and Act1 detected. During this work a new conidial colour mutant, fawn, was isolated and characterised. It is likely to be a valuable visual marker, especially in view of its interaction with other colour mutants.

Isoenzymes Detect Variation in Populations of Triatoma brasiliensis (Hemiptera: Reduviidae: Triatominae)

Triatoma brasiliensis is one of the most important vectors of Chagas disease in the semiarid zone of the northeast of Brazil. Intraspecific morphological and behavioural variation has been reported for different populations. Results for four distinct populations using eight isoenzymes are reported here. The literature describes three subspecies: T. brasiliensis brasiliensis Neiva, 1911; T. brasiliensis melanica Neiva & Lent, 1941 and T. brasiliensis macromelasoma Galvão, 1956. These subspecies differ mainly in their cuticle colour pattern and were regarded as synonyms by Lent and Wygodzinsky (1979). In order to evaluate whether the chromatic pattern is a morphological variation of different melanic forms within T. brasiliensis or due to interspecific variation, field collections were performed in localities where these three subspecies have been described: Caicó (Rio Grande do Norte), the type-locality for T. b. brasiliensis; Petrolina (Pernambuco) for T. b. macromelasoma and Espinosa (Minas Gerais) for T. b. melanica. A fourth distinct chromatic pattern was found in Juazeiro (Bahia). A total of nine loci were studied. Values of Nei's genetic distance (D) were calculated. T. b. brasiliensis and T. b. macromelasoma are the closest populations with a D=0.295. T. b. melanica had a D ³ 0.537 when compared to the others, a distance in the range of interspecific variation for other triatomine species

Ecotopes, Natural Infection and Trophic Resources of Triatoma brasiliensis (Hemiptera, Reduviidae, Triatominae)

Triatoma brasiliensis is considered as one of the most important Chagas disease vectors in the northeastern Brazil. This species presents chromatic variations which led to descriptions of subspecies, synonymized by Lent and Wygodzinsky (1979). In order to broaden bionomic knowledge of these distinct colour patterns of T. brasiliensis, captures were performed at different sites, where the chromatic patterns were described: Caicó, Rio Grande do Norte (T. brasiliensis brasiliensis Neiva, 1911), it will be called the "brasiliensis population"; Espinosa, Minas Gerais (T. brasiliensis melanica Neiva & Lent 1941), the "melanica population" and Petrolina, Pernambuco (T. brasiliensis macromelasoma, Galvão 1956), the "macromelasoma population". A fourth chromatic pattern was collected in Juazeiro, Bahia the darker one in overall cuticle coloration, the "Juazeiro population". At the sites of Caicó, Petrolina and Juazeiro, specimens were captured in peridomiciliar ecotopes and in wilderness. In Espinosa the specimens were collected only in wilderness, even though several exhaustive captures have been performed in peridomicile at different sites of this municipality. A total of 298 specimens were captured. The average registered infection rate was 15% for "brasiliensis population" and of 6.6% for "melanica population". Specimens of "macromelasoma" and of "Juazeiro populations" did not present natural infection. Concerning trophic resources, evaluated by the precipitin test, feeding eclecticism for the different colour patterns studied was observed, with dominance of goat blood in household surroundings as well as in wilderness

Description of the Oocysts of Three New Species of Eimeria (Apicomplexa: Eimeriidae) from Iguanid Lizards (Sauria: Iguanidae) of Central and South America

Three new species of Eimeria are described from iguanid lizards of Central and South America. The oocysts of each species have no micropyles or residua and the sporocysts lack Stieda bodies, but all have a sporocyst residuum. Eimeria sanctaluciae n.sp. was found in the St. Lucia tree lizard, Anolis luciae, collected from the Maria Islands, Lesser Antilles. The oocysts are spherical to subspherical, averaging 17.3 x 16.5 µm, with a single layered colourless wall; about 60% contain polar granules. The sporocysts are ellipsoidal and average 7.7 x 5.5 µm. Eimeria liolaemi n.sp. was recovered from the blue-gold swift, Liolaemus taenius, from Chile. The oocysts are spherical to subspherical, measuring 21 x 20.1 µm with a single-layered colourless wall. The sporocysts are subspherical and average 7.4 x 6.8 µm. Eimeria caesicia n.sp. is described from the Brazilian collared iguanid, Tropidurus torquatus. The oocysts measure 27.4 x 23.7 µm, are spherical to subspherical, with a bilayered wall, the outer surface of which appears pale blue in colour, the thin, inner wall appearing brown, when viewed by direct light under the optical microscope. The sporocysts are subspherical and average 9.4 x 7.2 µm. Unnamed polysporocystid oocysts with dizoic sporocysts are reported from the faeces of the lesser St. Vincent tree lizard, Anolis trinitatis and the possibility of spurious parasitism briefly discussed. In addition, oocysts of an unnamed Isospora sp. with a smooth oocyst wall which closely resembles I. reui were recovered from A. trinitatis.

Description of Pythonella scleruri n. sp. (Apicomplexa: Eimeriidae) from a Brazilian Bird Rufous-Breasted-Leaftosser Sclerurus scansor, 1835 (Passeriformes: Furnariidae)

Coccidian oocysts containing 16 sporocysts with 4 sporozoites in each were observed in a faecal sample from Sclerurus scansor collected in the Itatiaia National Park, southeastern region of Brazil. The oocysts are characterized by ellipsoidal shape measuring 42.5 x 32.8 mm, with smooth, thick double-layered wall of a greenish-orange colour. An oocyst residuum of numerous scattered granules among the sporocysts in sporulated ones; 16 round sporocysts, averaging 10.5 x 10 mm each containing four elongated sporozoites; presence of residuum; absence of Stieda body. The presently described coccidian, recorded for the first time in birds, is a new species named P. scleruri.