Anais da Escola Superior de Agricultura Luiz de Queiroz
Publish original articles that contribute to the scientific development of Agricultural Sciences.
Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Anais da escola superior de agricultura "Luiz de Queiroz"
Studies on the genus Melipona 1 - Introduction and acknowledgements. 2 - Systematica. Three modern trends in the systematics of the Meliponini are cited: Ducke (1916), Schwarz (1932) and Moure (1946); The 14 species known of the genus Meliponaare given. 3 - Contribution to the Biology. There are three castes in Melipona: drones, workers and queens, which are easily distinguished on account of the differences in size, color, proportions and behavior. While the queen of Apis emerges in a state of sufficient development to be fertilized and to begin the laying of eggs, the queen of Melipona, on the other side, in a glance seems undernourished, get having received the same food as the workers, both in quantity and in quality. They emerge with undeveloped ovaries and, only after the fertilized queen is dead or too old, virgin queens may be fertilized and begin to be fed by workers. After 15 to 30 days, according to the number of workers and the food gathered, the queen begins to lay eggs. The queens, drones and workers emerge from cells of the same size and with more or less the same quantity of food. Variations of the quantity of food do not change the caste, but only the size of the bee. The caste determination in Trigonai (another genus of Meliponini) depends evidently upon differences in nutrition. It is easily seen that the cells which furnish drones and workers are different in size, though equal in form, from those from which emerge the queens. Somie data concerning the biology of the Meliponini are given below: 1st - The number of eggs laid by a queen: Melipona quadrifasciata anthiodioides - in 44 days (July 9th to Aug. 22nd - 1946) 590 eggs, with an average of 13 eggs per day, and a maximum of 22 eggs per day. Trígona (Plebéia) mosquito, (Mirim-guassú) - from July 9th to July 24th 1946, 249 eggs. Prom Aug. 9th to Aug. 24th, 1946 laid 1035 eggs; with an average of 69 eggs per day and a maximum of 120 eggs. 2nd) - A table is given showing the percentage of drones observed in the total of individuals in samples of brood combs. (See Quadro I and Quadro EE). 3rd) - The duration of the several phases in the lives of the Meliponaworkers and queens is: Phases Worker Queen Hatching of the egg 4,5 to 6,5 days 4,5 to 6,5 days Larva 7 to 8 days 7 to 8 days Prepupa 5 to 5,5 days 4,5 to 5 days Pupa 15,5 to 18 days 11,5 to 15 days Total, from egg to imago 34 to 37 days 30 to 34 days It is mentioned that the Meliponini constructs large honey and pollen pots of characteristic size, and form both In natural hives and in experimental colonies in wooden boxes. The workers in weak colonies of M. Marginata and M. schencki produce little wax, and excepcionally, use brood cells for storage Instead of pots, showing that their reactions are very variable. Other details of the brood cell, such as brood cells disposition, construction, destruction, etc., are discussed. 4 - Anatomy of the reprodutive organs. The sexual organs of the male consist of: a) Two testicles envolved by a thin membrane, each of the testicles formed by four testicular tubes, b) two vasa deferentia, c) two vesiculae seminales, which are spherical and very small, d) one ejaculatory duct and e) the pente. There are no accessory glands as in Apis and Bombus. (BORDAS, 1895) See Fig. 6 and 46). The reprodutive organs of the female consist of: a) two ovaries, each formed by four ovardoles. The length of these pvarioles is: 1,7 to 2,0 mms. in the worker or sterile female, 11,1 to 11,5 mms. in the virgin queen and 76 mms. in the fecundated queen (measures taken on Meliponafasciata melano ven ter), b) two oviducts, c) vagina and d) spermatheca with a pair of glands. This same description is applied to Trígona and Bombus, varying the proportions. 5 - Citology Studies on the cytology of the genera Melipona and Trigona were carried out Ovaries òf the pupas queens and workers, testicles of prepupas and young pupas of drones, brains and other somatic' ttisues of larvae were examined. The details of the technique and the results are given. ;The somatic tissue of the females, both queens and workers, presents 18 chromosomes. The spermatogeneáfó is normal, following the type described for Apis by Meves (1907) with expulsion of a cytoplasmatic Bud in the first division, and a nucleated bud in the second, The sperfiuatogonia and spermatids show 9 chromosomes. 'Polyploid c cel|sl and tissues are fre'quent, even in the testicles but polyploid secondary spermatocytes do not go through a second meiotic division. No polyploid individuals have been found às yet. The number of chromosomes is the same in all Melipona, studied: M. fasciata, M. marginata, M scheneki. M. quadrifasciata, A. e. 18 in the female and 19 in the male. 6 - Determination cf castes of queen and worker. There are many papers discussing the problem of caste determination in the social insects (Bibliography in the papers of Light, 1943 and Wheeler, 1928)* Two,, theoriescome always under discussion: a) the. Blasjtógezüc or; genptypJc determination and b) the Trophogenfè or somatogenic one. In the first case, special genes are supposed to be responsible while in the second case the determination is by means of food or other environmental factors. No one doubts today that the caste of .males In Hyme-hoptera is genetically determined by arrhenotoky, wjth very few exceptional casss. The Meliponabees do not escape this rule, as shown by chromosome counts. The opinions aré however divided with regard to the female castes.
Meiose em Rhinocricus Padbergi Verhoeff, 1938
In the present paper the behaviour of the chromosomes in the spermatogenesis of the Myriapod Rhinocricus Padbergi Verhoeff, 1938 is studied. The primary spermatocytes are provided with 10 independent bivalents which separate normally giving rise to equivalent secondary spermatocytes. No indication of sex chromosomes has been found. Fusion of two bivalents or of four, two by two, has been observed, giving origin to secondary spermatocytes with 9 and 8 chromosomes respectively, in which fused chromosomes could be discovered. For analysing the facts the chomosomes of both, primary and secondary metaphases were separately counted from a total of 190 celis of four individuals and statistically treted. The X2-test gave insignificant results. Twenty chomosomes were counted in somatic tissues. The heterochròmatic parts of the leptotene threads were usually arranged in the periphery of the nucleus. In resting nuclei chromocenters can be observed in varyng number. Their chromosomal nature is revealed by the fact that when treated by KCÑ or KNOS they begin uncoiling.
Contribuições à teoria da genética em populações
1) The equilibrium in populations, initially composed of various genotypes depends essentially from the mode of reproduction the relative viability and fertility of the competing genotypes, and the initial frequencies. 2) We have to distinguish two main types of sexual reproduction: Cross fertilization or random mating where each individual has equal chances to be fertilized by any individual of the population, and Self-fertilization where each individum is automatically selfed. Finally we encounter cases of a mixed reproduction where there is no free intercrossing nor an absolute selfing. 3) Populations, heterozygous for one pair of genes and without selection. a) In cross fertilized populations equilibrium is reached in acordance with the Hardy-Wéinberg rule, in the first generation: Inicial : AA /u + Aa /v + aa/u = 1 Equilibrio ( u + v/2)² + 2 ( u + v/2 ) (w + v/2) + ( w + v/2)²= 1 Equilibrio ( u + v/2)² + 2 (u + v/2) ( w + v/2) + ( w + v/2)² = p o² + 2. po.qo + q o² = 1 b) In self fertilized populations equilibrium will be reached thermiticialy by the complete elimination of all heterozigotes, but a, sufficient approach to equilibrium may . be reached quickly: Frequência mº Geração Final AA u + 2m-1/2m+1 v u + 1/2 v Aa 2/ 2m + 1 v - aa w + 2m-1 / 2m +1 v w + 1/2 v c) In populations with mixed reproduction, the equilibrium depends upon the relative frequencies of crossing and selfing* and the final values for some cases are given in Quadro I. 4) Survival Indices - Mathematical formulas are simplified if we introduce special survival indices for the homozygotes in relation to the survival of the heterozygotes. If we designate the absolve survival values of the three genotypes AA, Aa and aa, by x, y and z. we may give the following mathematical definition: x [ A A] : y [ Aa] : z [ aa] = x/y [ A A] : [ Aa] : z/ y [aa] = R A [ AA] : 1 [Aa] : Ra [aa] Thus the value of R can have any value between zero, i. e. complete elimination of homozygotés, and infinite, i. e. complete elimination of heterozygotes. The terms (1 -K) of Haldane and (1 -S) or W of Wright do not have this mathematical property, and may have only values from zero to one Evidently, in accordance with the nature of the elimina tory process, we shall have to subdivide these indices of total survival R into at least two main components: the survival during the vegetative phase and the survival of gametes during the reproduction phase. These two componentes are united by the following equation R = RA . RR 5) Populations with random mating and selection. a) The final equilibrium, which is independent from the Initial gene or genotype frequencies, is reached when the genes and the zygotic genotypes are present in the following proportions: (Quadro 2). Po/ qo = 1- Ro/ -R A [AA] ( 0,5 - Ra). R AV [Aa] = 4. ( 0,5 - Ra) . (0.5 -R A) [aa] ( 0,5 - R A)² . Rav b) Formulas are given which permit the calculus of frequencies in intermediate generations. 6) Discussion of special cases. a) Heterotic Genes. (Quadro 3 and Fig. 1). Ra < 1; Ra < 1 Inicial : Final : p (A)/q(a) -> 1-ra/1-ra = positivo/zero = infinito At equilibrium both genes remain present in the population, and their frequency will be increased or decreased whenever the initial frequencies were bigger or smaller than the values expected at equilibrium. b) Letais or semiletal, recessives genes. (Quadro 4 and Fig. 2). Rª ; Oz Ra < 1 Inicial : Equilibrio biológico Equilíbrio Matemático pa(A)/q(a) -> positivo /zero -> 1- Rq/ 1-Ra = positivo/negativo Equilibrium will be reached when the gene which causes the reduction of viability or fertility of homozigotes, is eliminated from the population. c) Semiletals, and parcially dominant genes. (Quadro 5 and Fig. 3). Rª ; Oz Ra < 1 Inicial : Equilibrio biológico Equilíbrio Matemático pa(A)/q(a) -> positivo /zero -> 1- Rq/ 1-Ra = positivo/negativo d) Incompatible Genes. Ra > 1 ; Ra > 1; Ra > Ra Equílibrio/biológico p (A)/ q(a) -> positivo/zero Equilibrio matemático -> positivo/ zero -> zero/negativo -> 1-Ra/1 - Ra = negativo/negativo In these two cases we have to distinguish between the biological and the mathematical equilibrium. The first will be reached when one of the genes has a frequency equal to zero, While negative values can have a mathematical meaning only. Thus biological equilibrium will be reached with the elimination of the gene which causes a relatively lower viability of the respective homozygotes. However we must note still one exception in the last case of incompatible genes: When both genes have the same initial frequency and when the respective survival values are also equal and larger than one, both the genes will remain in the population, and the homozygotes will become more frequent than the heterozygotes, thus furnishing an isolating mecha-nisme. e) Two special cases were discussed in some detail: differential elimination in the two sexes, and gametophite competition. (Quadro 6 e 7 e Pig. 4 a 6). 7) Populations with self-fertilization. a) Equilibrium will be reached when the three genotypes are present in the following proportions. (Quadro 8). [AA] ( 0,5 - Ra). R AV [Aa] = 4. ( 0,5 - Ra) . (0.5 -R A) [aa] ( 0,5 - R A) . Rav b) Formulas are given which permit the determination of genotype frequencies in intermediate generations. 8) Special cases We may say that, in a general way, the diferences (1 -R) in the formulas for populations with randon mating and (0.5 -R) in selfed populations, occupy corresponding positions. a) Heterotic Genes. (Quandro 9 and Fig. 7). RA menor do que 0,5 Ra menor do que 0,5 At equilibrium both genes remain in the populations and the three zygotic genotypes reach standard values, indepenr dent from the initial frequencies. b) In all other cases, i. e. where one or both values of the survival indices are equal or bigger than 0,5, the following situation arises: When the survival values for both ho-mozygotes are equal, equilibrium will be reached when the population contains only these homozygous with identical. When the survival values are different, equilibrium will be reached when only the homozygotes of the genotype whith the higher survival value remain in the population, while the other homozygotes and all heterozygotes have disappeared. 9) The result of variations in the initialgene frequencies (Fig. 8), of sudden changes in survival values (Fig. 9) and of the mode of reproduction (Fig. 10) are discussed in some detail. 10) References to problems of applied genetics. After some general observations on population genetics and applied genetics, two problems were discussed in some detail: a) Homogenization: - Formulas and data (Quadros 11 e 12) are given which show that random mating systeme are very inefficient means to obtain homozigous populations, and that either sslfing or some system of consanguineous matings should always be applied. These tables may also serve to obtain estimates as to the number of inbred generations necessary to obtain certain levels of homozygosis. b) Heterosis may evidently be obtained by the classical method of "inbreeding and outbreeding" or by the establishement of balanced populations containing genes with a heterotic effect, both with regards to their general vigor and productivity, as to their survival values. 11) Considerations on the evolutionary mechanismes. a)The importance of heterotic survival values is discussed, and references are made to a special publication on the subject (Brieger, 1948). b) Recessive lethals and semilethals. It is evident from the discussions that genes of this nature should be eliminated from the populations. But observations in corn, and in Drosophila, leave little doubt that genes such as tassel-seed, barren-stalk, numerous types of defective seeds, etc., are relatively frequent in populations which have not been subjected previously to a scientific selection. In order to explain this discrepancy, new studies are necessary in oder to find out whether survival in homozygotes, are not at the same time heterotic for the survival values. c) Dominant semilethals - It must be expected that these genes are speedily eliminated from the populations, and in fact, they are rare in natural populations. b) Incompatible genes - These genes also should be very rare, except perhaps in the special case where they serve to establish an isolating mechanism.Very Utile is known howewer with respect of them.
Análise da variação qualitativa em amostras pequenas
The main object of the paper is a revision of the methods for the statistical analysis of qualitative variation in small samples. In general, this analysis is carried out by means of two tests, which are mathematically different, but give identical statistical results : the analysis of relative deviates, i.e. of te quotients between the deviate of the observed frequency, with regerds to the expected frequency divided by its standard error, or an analysis using the X2-test. We must distinguish, in our discussion, two cases, which are quite different. The basic distribuition of all cases of qualitative variation is the binomial. If we expect any qualitative result to occur with probability p ,its non-occurence having probability q equal to (1-p>;, the expectancy to have, 0, 1, 2... m cases or individuals of the expected type in N trials may be calculated by expanding the binomial. (P + q)N Such a binomial may be substituited by other distributions in two special cases: a) If p is very small and thus q is aproaching the value one, we may substitute the binomial by a Poisson series. b) If the exponent N becomes very large, the binomial is approaching a continous distribution, i.e. the normal or Gaus-sean distribution. Only in the second case, the application of the X2-test is really justified, and in all other cases, we are dealing only with approximations. Indvidual values of X2- should follow a modified distribution of Pearson, with nl = 1; n2 = inf. Since this distributon corresponds exactly to one half of the Gaus-sean dstribution, it follows that the b lateral limits of the latter are equal to the unilateral limits of the former. These points have been explained fully elsewhere (BRIEGER, 1945, 1946). We have row to decide which value of p may be accepted as a satisfactory limit between a Poisson and a binomial series. Quadros 1-3, show that the conventional limit of pr=0,l is fully justified, from a practical point of view. In these tables we find in the second column from the left the frequencies of a Poisson series, and in the second column from the night the values of X2 based, as explained, on a modified Gaussean distribution. The two columns in the centre correspond to two binomials and it is evident that the first with p=0,05 has its limits of precision almost at the same level as the Poisson series, while the other with p=0,l agrees fairly well with the limits of the X2 series. Thus is seems justified to treat separately the cases with expected frequencies of p equal or smaller that 0,1 and those with p larger than 0,1. A) When the different classes, wich may be two (alternative variability) or more (multiple variability, have all expected frequences of p between 0,1 and 0,9, we may use practically the X2 test with out any restriction. Quadros 8 and 9 show that the limits calculated for two binomials are practically identical with those of the X2 total. Nevertheless a special table is given (table 11) for the limits of binomials with p equal 0,5 and 0,25 and expected class frequencies of less than 10. One must not forget that in these cases the individual values of X2 for each class are of less importance than their sum, the X2 total. The value of X2 for each class may be calculated either with the general formula, using actual numbers or with a modified formula using percentages : X² = ( f obs - f esp)² = (f esp - NP)² f esp NP = (f obs - p%)2.N p% 100 In the case of alternative variability, we may calculate directly the value of the X2 total, by squaring the relative deviate : x² total = (f obs - f esp)² = (f obs - Np)² f esp NP = ( f obs % - p %) 2. N p % (100 - p%) B) If we have one or more classes with expected frequencies equal os smaller than 0,1 we have to deal with a Poisson series. As shown in Quadro 7 the agreement between the limits of the Poisson series and the X2-test for one classe (simple X2) is only satisfactory when the expected frequency, is larger than 10 and tolerable when it is between 5 and 10. If the expected number should be smaller still, we cannot use anymore the X2-test, but should use the values given in table I, calculated for Poisson series witr expected frequencies (in numbers) from 1 to 15. Very frequently the X2-test is used for comparing in detail observed and expected distributions, a test called sometimes "homogeneity test". Since generally the frequencies in the marginal classes are less than five, we have to accumulate by summing the frequencies from the more extreme classes towards the center, untill all accumulated and remaining values are at least equal to five. The statistical information, lost in this accumulating process, may be recovered when comparing the individual class frequencies with the limiting values in table 1. As ilustration, a concrete exemple is discussed. (Quadro 10). The formulas and tables of this paper have been tried out first during sometime and, having been found of considerable value in the execution of statistical analysis, are now published. In order to permit a more general use, a table of ordinary limits for the X2-test is included, taken from a recent paper (BRIEGER, 1946).
Alimentação dos marrecos II: ração de marrecas para postura - Ração balanceada x Ração grosseira, barata
The author studied in this paper the substitution of a balanced ratio for an economic ratio composed of 50% of sugar beet and 50% of balanced ratio, in feeding ducks egg production. It was found that the combination had no advantage since the production of eggs was very much reduced.
A influência da alimentação verde na postura
A test was conducted at Poultry Department of "Luiz de Queiroz" School of Agriculture to prove the effect of green feed on egg production. One hundred Rhode Island Red hens at plain laying period were divided in ten pens. The lot A was constituted of pens 1 to 5 and the lot B of pens 6 to 10. During 16 days the pens 1 to 5 did not receive green feed and the pens 6 to 10 received it with abundance. After and for a period of 30 days the situation was inverted. The analysis were made considering, a) the production of all chickens and b) discarding the chickens with irregular laying. In both cases the results were statistically insignificant, proving that green feed did not improve egg production.
Comparação das raças Rhode Island Red, Light Sussex e seu mestiço: ovos, pintos e frangos
The breeds Light Sussex, Rhode Island Red and the hibrid Light Sussex x Rhode Island Red, from the Poultry Department of "Luiz de Queiroz" School of Agriculture, at Piracicaba, S. Paulo, were studied in this paper, Tre authors, analysing eggs, pullets and chick growing arrived to the following conclusion: a) eggs of the Light Sussex breed were haevier; b) the Light Sussex breed was early maturing; c) the cross studied did not show hibrid vigor.
III - A ocorrência das células anexas dos estômatos na família Rubiaceae
In the present paper the author gives the final results of his studies about the significance of the two annex cells of the stomata of the Rubiaceae as anatomical family character, part of which has been previously published. After having verified that in the Order Rubiales the Family Rubiaceae is the unique to show stomata provided with two annex cells differing in size and shape, the author has extended his observation over 553 species belonging to 107 genera, having not found till the present time a single discrepant case. Even though in the future some species not yet investigated come to show stomata devoid of ajinex cells, even In this case the annex cells do not lose their importance at least as specific or generic character. However, the author is inclined to consider, on the light of-the facts in hand, the two annex cells of the Rubiaceae stomata as good anatomical family character.
Comportamento da raça Light Sussex em Piracicaba
Three years of observations on Light Sussex breed conducted at the Poultry Departament of "Luiz de Queiroz" School of Agriculture are reported in this paper. The breed was compared mainly with the Rhode Island Red and the following conclusion obtained : The Light Sussex is fast growing, early maturing heavier, fine fleshed, more persistent and with greater dutchs. greater groodiness and lays larger eggs. The breed shows quality of adaptation being recommended for town or farm flocks in the same way generally used in England. Exceptionally could be recommended for commercial flocks.
Análise do tamanho e da forma do ôvo em galinhas das raças Rhode Island Red e Light Sussex e do híbrido entre essas duas raças
Size and shape in eggs of Rhode Island Red and Light Sussex breeds and in the hibrid Rhode x Sussex were studied. These characters are influenced by quantitative genes. Major and minor diameter were used for estimating size of the eggs and the ratio minor/major diameter for shape indice. It was found, in the material analyzed, that: a) the eggs laid by the sa- me chick are pratically uniform; b) the correlation coeficient between major and minor diameter is weak; c) Rhode Island Red has short eggs than Light Sussex; d) short eggs is dominant on long eggs; e) egg shape is the same in Rhode Island Red and Light Sussex breeds and different in the hibrid, which has rounder eggs than the breeds.
This paper deals with the results obtained in one experiment with rabbits, made in order to see which treatment should be the best one against ear canker. Five treatments, each one with 3 rabbits, were tried : Detefon, Insect-o-Blitz, Turpentine with oil, DDT with 10% of vaseline and Kerozene. The best results were obtained with DDT-10% and vaseline-90% which proved to be more efficacious, saving the animals quickly than the other treatment.
Determinação do sexo em pintos da raça Rhode Island Red
This paper refers to sex differentiation in one day chicks of the Rhode Island Red Breed, which has been selected by the laying capacity in the flock pertaining to the Escola Superior de Agricultura "Luiz de Queiroz". The A., taking as a basis the light staining of the anterior edge of the wing, the fair ring of down of the chick leg, immediately a bove the tibiotarsic joint, and dark spot that occurs sometimes near the posterior angle of the eye, besides other characters of minor importance, was able to separate correctly 197 out of 201 chicks, what represents 98,01% of the total number.
A influência dos pigmentos amarelo -laranja de vários alimentos na coloração da gema de ôvo de galinha
The effect of different feeds in comparison with that of maize grains on the egg yolk color was observed. It was found that deep orange and yellow orange maize give satisfactory coloration to the yolk, respectively orange and yellow. The most intense color was observed when green feed was used in combination with deep orange maize. Green feeds as chicory, alfafa, cabbage, welsh onion and banana leaves and alfafa or chicory meal proved to be good in giving orange color to the yolk. Yellow yolk was obtained when Guinea grass or carica fruit were used in the ration. Carrot and beet without leaves did not give satisfactory color to the egg yolk. The observations with other feeds are being continued.
Studying the application of those methods of microanalysis which avoid costly instalations and atempting to combine high precision with low cost, the author recomends a new method consisting of the following : a) exposure of a surface of 530.66 mm2 of Zn to the action of the acid. b) instalation of 3 series of HgBr2 paper in test tubes with an internal diameter of respectively 3,5 and 9 mm. c - mouting between two slides, covering the margins (with parafin etc.) with parafin in order to conserve the results of the determination without change due to the action of light or moisture. d) the results can be compared at a level of 0.00001 mgr. A203 or 0.000007575 mgr. As.
Cálculo da potência dos motores para moendas de cana de açúcar
O conhecimento da potência necessária para a moagem da cana de açúcar, é de relevante importância, não só para o fabricante de moendas, como para o usineiro e o tecnólogo. Os autores reportando-se ao processo usado por LEHKY no cálculo da potência dos motores destinados ao acionamento das moendas das usinas de açúcar: 1.° - esclarecem a dedução das fórmulas apresentadas por aquele notável engenheiro dos Estabelecimentos Skoda; 2.° - modificam o fator 1,305 da fórmula original usada no cálculo da potência necessária para vencer o atrito da bagaceira, para 1,2987, quando se considera a velocidade linear dos cilindros em metros por minuto; 3.° - apresentam exemplos numéricos de aplicação direta das fórmulas, para diferentes tipos de moendas, demonstrando que o processo usado por LEHKY é praticamente aplicável a qualquer moenda.
Comportamento dos cromossômios no gênero Hypselonotus (Hemiptera -Coreidae)
The three species studied have 19 chromosomes, being one heterochromosome, one pair of microchromosomes and 8 pairs of autosomes. The microchromosomes of Hypselonotus fulvus are amongst the largest we know. During the synizesis, in Hypselonotus fulvus, we can see in several strands that scape from the chromatic knot a place in which they are widley open. As, in that phase the chromosomes have both ends converging to the same place, the openings suggest a side-to-side pairing of the chromosomal threads. The tetrads are like that studied by Piza (1945-1946). The bivalents are united side by side at their entire length. The unpaired part at the midle of the bivalents gives origin to the arms of the cross-shapede tetrads. The chromosomes have a kinetochore at each end. The bivalents sometimes unite their extremities to form ring-shaped figures, which open themselves out before metaphase. The tetrads are oriented parallelly to the spindle axis. At telophase the kinetochores repeli one another, the chiasmata, if present, slip toward the acentric extremities and the chromosomes rotate in order to arrange themselves parallelly to the axis of the new spindle. Separation is therefore through the pairing plane. In the spermatogonial anaphase of Hypselonotus subterpunctatus the chromosomes are curved to the poles, like those described by PIZA (1946) and PIZA and ZAMITH (1946). The sex chromosomes in Hypselonotus interruptus and Hypselonotus fulvus appears longitudinally divided. It is oriented with the ends in the plane of the equator and its chomatids separate by the plane of division. In the second division the sex chromosome, provided as it is with an actve klnetochore at each end, orients itself with its length parallelly to the spindle axis and passes undivided to one pole. Sometimes it is distended between the poles. This corresponds to case (a) established by PIZA (1946) for the sex chromosomes of Hemiptera In Hypselonotus subterpunctatus the sex chromosome, in the first division of the spermatocytes, orients like the tetrads and divides transversaly. In the second division, as its kinetochore becomes inactive, it remans monocentric, does not orient in the spindle, and is finally enclosed in the nearer nucleus. In the secondary telophase it recuperates its dicentricity like the autosomal chromatids. This behavior corresponds to case (c) of PIZA (1946).
Determinação do sexo do pinto pela forma do ovo
The author has studied in this paper the correlation between egg form and sex of chicks at hatching time. Two me- thods were tried: in one the eggs were separated in two groups according to the edge form, round or alonga te; in the other the eggs were classified into two types according to te relation between the minor and the major diameter and above or under the relation mean. In both cases it was found that the egg form has no influence on sex. The sex determination of the pullets was made by the method of JAAP, improved in our Department by JARDIM.
Os pigmentos amarelo-laranja do grão de milho como precursores da vitamina a na alimentação dos pintos
Two commercial types of maize; largely used in the State of S. Paulo, Brazil, were tried as source of pró-vitamin A in growing pullets. The amount of pró-vitamin A was found to be practically doubled in "Cateto", a flint type with deep orange grains when compared with "Armour", a dent type with yellow oiange grains. Both "Cateto" and "Armour" proved to be equally good in preventing avitaminosis A, when used in the same proportion in the ration (70%). White corn used for comparison produced strong avitaminosis A.
Alimentação dos marrecos I: forragem verde
Resultado do estudo de um pequeno lote de opiliões
A determinação dos números de indivíduos mínimos necessários na experimentação genética
The main object of the present paper consists in giving formulas and methods which enable us to determine the minimum number of repetitions or of individuals necessary to garantee some extent the success of an experiment. The theoretical basis of all processes consists essentially in the following. Knowing the frequency of the desired p and of the non desired ovents q we may calculate the frequency of all possi- ble combinations, to be expected in n repetitions, by expanding the binomium (p-+q)n. Determining which of these combinations we want to avoid we calculate their total frequency, selecting the value of the exponent n of the binomium in such a way that this total frequency is equal or smaller than the accepted limit of precision n/pª{ 1/n1 (q/p)n + 1/(n-1)| (q/p)n-1 + 1/ 2!(n-2)| (q/p)n-2 + 1/3(n-3) (q/p)n-3... < Plim - -(1b) There does not exist an absolute limit of precision since its value depends not only upon psychological factors in our judgement, but is at the same sime a function of the number of repetitions For this reasen y have proposed (1,56) two relative values, one equal to 1-5n as the lowest value of probability and the other equal to 1-10n as the highest value of improbability, leaving between them what may be called the "region of doubt However these formulas cannot be applied in our case since this number n is just the unknown quantity. Thus we have to use, instead of the more exact values of these two formulas, the conventional limits of P.lim equal to 0,05 (Precision 5%), equal to 0,01 (Precision 1%, and to 0,001 (Precision P, 1%). The binominal formula as explained above (cf. formula 1, pg. 85), however is of rather limited applicability owing to the excessive calculus necessary, and we have thus to procure approximations as substitutes. We may use, without loss of precision, the following approximations: a) The normal or Gaussean distribution when the expected frequency p has any value between 0,1 and 0,9, and when n is at least superior to ten. b) The Poisson distribution when the expected frequecy p is smaller than 0,1. Tables V to VII show for some special cases that these approximations are very satisfactory. The praticai solution of the following problems, stated in the introduction can now be given: A) What is the minimum number of repititions necessary in order to avoid that any one of a treatments, varieties etc. may be accidentally always the best, on the best and second best, or the first, second, and third best or finally one of the n beat treatments, varieties etc. Using the first term of the binomium, we have the following equation for n: n = log Riim / log (m:) = log Riim / log.m - log a --------------(5) B) What is the minimun number of individuals necessary in 01der that a ceratin type, expected with the frequency p, may appaer at least in one, two, three or a=m+1 individuals. 1) For p between 0,1 and 0,9 and using the Gaussean approximation we have: on - ó. p (1-p) n - a -1.m b= δ. 1-p /p e c = m/p } -------------------(7) n = b + b² + 4 c/ 2 n´ = 1/p n cor = n + n' ---------- (8) We have to use the correction n' when p has a value between 0,25 and 0,75. The greek letters delta represents in the present esse the unilateral limits of the Gaussean distribution for the three conventional limits of precision : 1,64; 2,33; and 3,09 respectively. h we are only interested in having at least one individual, and m becomes equal to zero, the formula reduces to : c= m/p o para a = 1 a = { b + b²}² = b² = δ2 1- p /p }-----------------(9) n = 1/p n (cor) = n + n´ 2) If p is smaller than 0,1 we may use table 1 in order to find the mean m of a Poisson distribution and determine. n = m: p C) Which is the minimun number of individuals necessary for distinguishing two frequencies p1 and p2? 1) When pl and p2 are values between 0,1 and 0,9 we have: n = { δ p1 ( 1-pi) + p2) / p2 (1 - p2) n= 1/p1-p2 }------------ (13) n (cor) We have again to use the unilateral limits of the Gaussean distribution. The correction n' should be used if at least one of the valors pl or p2 has a value between 0,25 and 0,75. A more complicated formula may be used in cases where whe want to increase the precision : n (p1 - p2) δ { p1 (1- p2 ) / n= m δ = δ p1 ( 1 - p1) + p2 ( 1 - p2) c= m / p1 - p2 n = { b2 + 4 4 c }2 }--------- (14) n = 1/ p1 - p2 2) When both pl and p2 are smaller than 0,1 we determine the quocient (pl-r-p2) and procure the corresponding number m2 of a Poisson distribution in table 2. The value n is found by the equation : n = mg /p2 ------------- (15) D) What is the minimun number necessary for distinguishing three or more frequencies, p2 p1 p3. If the frequecies pl p2 p3 are values between 0,1 e 0,9 we have to solve the individual equations and sue the higest value of n thus determined : n 1.2 = {δ p1 (1 - p1) / p1 - p2 }² = Fiim n 1.2 = { δ p1 ( 1 - p1) + p1 ( 1 - p1) }² } -- (16) Delta represents now the bilateral limits of the : Gaussean distrioution : 1,96-2,58-3,29. 2) No table was prepared for the relatively rare cases of a comparison of threes or more frequencies below 0,1 and in such cases extremely high numbers would be required. E) A process is given which serves to solve two problemr of informatory nature : a) if a special type appears in n individuals with a frequency p(obs), what may be the corresponding ideal value of p(esp), or; b) if we study samples of n in diviuals and expect a certain type with a frequency p(esp) what may be the extreme limits of p(obs) in individual farmlies ? I.) If we are dealing with values between 0,1 and 0,9 we may use table 3. To solve the first question we select the respective horizontal line for p(obs) and determine which column corresponds to our value of n and find the respective value of p(esp) by interpolating between columns. In order to solve the second problem we start with the respective column for p(esp) and find the horizontal line for the given value of n either diretly or by approximation and by interpolation. 2) For frequencies smaller than 0,1 we have to use table 4 and transform the fractions p(esp) and p(obs) in numbers of Poisson series by multiplication with n. Tn order to solve the first broblem, we verify in which line the lower Poisson limit is equal to m(obs) and transform the corresponding value of m into frequecy p(esp) by dividing through n. The observed frequency may thus be a chance deviate of any value between 0,0... and the values given by dividing the value of m in the table by n. In the second case we transform first the expectation p(esp) into a value of m and procure in the horizontal line, corresponding to m(esp) the extreme values om m which than must be transformed, by dividing through n into values of p(obs). F) Partial and progressive tests may be recomended in all cases where there is lack of material or where the loss of time is less importent than the cost of large scale experiments since in many cases the minimun number necessary to garantee the results within the limits of precision is rather large. One should not forget that the minimun number really represents at the same time a maximun number, necessary only if one takes into consideration essentially the disfavorable variations, but smaller numbers may frequently already satisfactory results. For instance, by definition, we know that a frequecy of p means that we expect one individual in every total o(f1-p). If there were no chance variations, this number (1- p) will be suficient. and if there were favorable variations a smaller number still may yield one individual of the desired type. r.nus trusting to luck, one may start the experiment with numbers, smaller than the minimun calculated according to the formulas given above, and increase the total untill the desired result is obtained and this may well b ebefore the "minimum number" is reached. Some concrete examples of this partial or progressive procedure are given from our genetical experiments with maize.
Cromossômios de Dysdercus (Hemiptera-Pyrrhocoridae)
Breve notícia sôbre a espermatogênese de Lutosa brasiliensis Brunner (Tettigoniodea-Stenopelmatidae)
Lutosa brasiliensis, an Orthopteran Tettigonioidean belonging to the family Stenopelmatidae is referred to in this paper The spermatogonia are provided with 15 chromosomes, that is, 7 pairs of autosomes and a single sex chromosome. One pair of autosomes is much larger than the rest, two pairs are of median sized elements, and four pairs are of small ones. The daughter sex chromosomes show at anaphase great difficulty in reaching the poles, being left for a long while in the region of the equator where they are seen stretched one after the other on the same line or lying side by side in different positions. When the spermatogonium divides each daughter cell gets passively its sex chromosome. Though slowly, the sex chromosome finishes by beins enclosed in the nucleus. Its behavior may be attributed to a very weak kinetic activity of the centromere. In view of se pronouced an inertness of the sex chromosomes, two things may be expected : primary spermatocyte nuclei with two sex chromosomes, and primary spermatocytes with the sex chromosome lying outside the nucleus. Both situations have been discovered. The latter, together with the delay of the spermatogonial sex chromosome in reaching the poles suggested to the anther the mechanism which might have given origin to the cases in which the sex chromosome normally does not enter the nucleus to rejoin the autosomes, remaning outside in its own nucleus. It may well be supposed that accidents like that found in the present individual have turned to be a normal event in the course of the evolution of some species. Trie primary spermatocytes are provided with chromatoid bodies which remain visible all over the whole history of the cells and pass to one of the resulting secondary spermatocytes, the larger of them being found later in the area occupied by the tails of the spermatozoa. No relation of these bodies to nucleoli con?d be established. Pachytene and diplotene nuclei are normal Metaphase nuclei show 7 autosomal tetrads, one of which being much larger than the rest. At this stage the chromosomes have a pronounced tendency to form clumps. Even when they are separated from each other they generally appear competed by chromosomal substance. The sex chromosome Hes always in one of the poles, being enclosed in the nucleus formed there. The stickness of the chromosomes can also be noted at anaphase. Telophase chromosomes distend them- selves for giving origin to secondary spermatocyte nuclei in a state comparable to a beginning prophase. As the secondary spermatocytes approach metaphase the autosomes appear entirely divided except at the kinetochore where the chromatids remain united. In the division of the secondary spermatocytes nothing else merits special reference.
Cálculo de coeficientes das reações químicas pelas valências oxidadas e reduzidas
Uma raça cromossômica natural de Tityus bahiensis (Scorpiones-Buthidae)
A natural chromosomal race of Tityus babiensis (Scorpiones Buthidae) is described in the present paper. Five males and seven females received from St. Joaquim, State of S. Paulo, gave the following interesting results: All the spermatogonia of the five males were provided with 9 chromosomes of different sizes. All primary spermatocytes showed at metaphase one independent bivalent of normal shape and a complex group formed by 7 chromosomes which have exchanged parts. Some of the chromosomes associated in the complex group, to Judge by their behavior, were composed of fragments of three different chromosomes, being thus paired with three other members of the compound group. The manner in which all the 7 components of the group have paired with each other showed to be very constant. They gave always origin to a double-cross configuration, the longst branch of which being formed by a long chromosome paired with two components of the group and with a third chromosome that did not belong to the group. The chromosomes of the independent bivalent separate regularly, going to different poles. From the 7 elements of the compound group, 4 go to one pole and 3 to the opposite one. Consequently, secondary spermatocytes with 4 and 5 chromosomes are produced. The females, so far as it can be inferred from the study of the follicular cells of the ovariuterus, have 10 chromosomes. These females are, therefore, considered as being monogametic, that is, as producing eggs with 5 chromosomes. A sex-determining mechanism arose in this manner, the spermatozoa with 5 chromosomes giving origin to females and those with 4 to males. The fact that the sex chromosome is one of the elements taking part in the formation of the group, seems highly interesting to the author. Tetraploid cysts have been occasionally found in the testis. In one individual the chromosomes of the tetraploid primary spermatocytes behaved as expected, forming a group of 14 elements, and two independent pairs or a tetravalent group In another individual, the chromosomes of the tetraploid cells have formed two independent groups of 7, and two independent pairs, as if both chromosomal sets were by their turn entirely independent frcm one another. This fact is certainly not devoid of special interest. The males as well as the females studied in this paper differed in nothing from the typical members of the species. The unique differential character of the new race is found in the umber and behavior of its chromosomes. It is highly remarkable that the occurrences which have transformed the 6 chromosomes normally present in the species into a new set of 9 elements, 7 of which have been profoun- dly altered in their structure, do not show any influence on the morphology of the organism. This fact, together with those found in the salivary-chromosomes races of Drosophila and Sciara. compromises strongly the genetical concept of position effects.