RCAAP Repository

In order to test Piza's conclusions regarding the dicentricity of Hemipteran chromosomes, two species of bugs of the family Coreidae, namely, Anasa sp. and Leptoglossus stigma (Herbst), are studied in the present paper. a) Anasa sp. - The male of this species has 21 chromosomes, that is, 20 pairs of autosomes and a single sex chromosome. The latter divides equationally in the first division of the spermatocytes and passes undivided to one cell in the second division. In this it moves with its longer axis parallelly to the spindle axis and shows fibrillar connections with both poles. Special attention was paid to the behavior of the chromosomes in the anaphase of the spermatogonia. As it was previously stated (Piza 1946 and 1946a) with regard to other species, the chromosomes are here attached to the spindle by both ends and begin to move toward the poles strongly curved to them. No intercalary fibers could be detected although their existente may not be denied by theoretical reasons developed in another paper (Piza 1946). Mitoses in somatic tissues of the embryo were equally studied. Careful examination of anaphase chromosomes in a great number of cells showed that the chromosomes behave exactly as in the spermatogonia, being equally attached to the spindle by the extremities alone and moving with their ends looking to the pole. A weak median constriction sometimes replaced by a slightly clearer space was observed in prometaphase and even in metaphase chromosomes of the spermatogonia as well as the somatic cells, having already been referred to in the case of Diactor bilineatus. (Piza 1945). Hemipteran chromosomes being considered as iso-chromosomes originated by a longitudinal spliting of the monocentric chromosomes resulting from the second division of the spermatocytes, the median aspect just mentioned may be regarded as the point of union of the separated halves. (See origin of dicentricity in Piza 1946). b) Leptoglossus stigma - This species has spermatogonia provided with 20 pairs of autosomes and one sex chromosome whose behavior differs in nothing from what was stated in regard of the preceding species. In the primary spermatocytes nothing meriting special mention was observed. Orientation, connection with the poles and movements of the sex chromosome in the secondary spermatocytes confirm the views already developed.

1) Tetraploid plants of cassava (Manihot utilissima Pohl) obtained by colchicine treatment are smaller than diploid plants and an analysis of their growing habits showed that tetraploid clones were not uniform and could be divided into two groups : group one : plants with stalks so thick as but shorter than the diploid plants: group two : plants wich stalks shorter as and thiner than the diploid ones (See tables 1 and 2). 2) Production of roots and stalks was studied in one experiment of randomized blocks and one vegetative cicle of the plants, (about 10 months); diploid clones are more productive and the tetraploid clones are very variable (Table 10). The Índice stalk/root weight is smaller in diploid clones, thus showing that production of roots in relation to stalks in the tetraploid plants is smaller than in diploid plants. Tetraploid plants are slower in growing habits during the beginning of the development (Figs. 18 and 20 to 24). 3) One experiment of randomized lines of 15 plants each and two vegetative cicles of the plants (about 20 months) confirms the results obtained in the experiment of one vegetative cicle regarding the production of roots and stalks. However, the indice stalk/root in plants with two vegetative cicles is the same (i = 0,30) for all clones (diploids and tetraploids) and is identical with the indice for diploid plants with one vegetative cicle, indicating that in plants with two vegetative cicles the production of roots in relation to stalks is the same both in diploid and tetraploid clones. 4) The production of roots and stalks was studied in one systematic experiment of 3 clones, in blocks of about 100 plants each: diploid clone n.° 8 and tetraploid clones n.° 2 and 6. The results obtained confirm the difference between tetraploid and diploid clones and also between the two tetraploid clones involved in the experiment (see table n.° 26 and figs. 25, 27 and 28.) The commercial value of tetraploid clones could be established only after other experiments (more tetraploid than diploid plants in the same area) since the production per plant of tetraploid clones is smaller than the diploid ones. The tetraploid clone n.° 6 has plants very small, of low production of roots and did not support field conditions. It is suggested that this clone should be good for horticultural conditions. 5) The starch contents is the same in all tetraploid and diploid clones studied (see table n. 28) and in two other clones of bitter cassava (n.°s 9 and 10) included for comparison in the analysis.

The main facts presented in this paper may be summarized as follows: 1) Corizus (Liorhyssus) hyalinus (Fabr.) has primary spermatocytes provided with 6 autosomal tetrads, one pair of microchromosomes and one sex chromosome. 2) The two microchromosomes present in this species sometimes appear at the primary metaphase as an unequal pair of minute elements. In the secondary spermatocytes the unique microchromosome present may be in the limit of visibility or entirely invisible. This invisibility may be partly due to a loss of colourability. 3) The sex chromosome divides transversely in the first division of the spermatocyte, passing undivided to one pole in the second one. In the latter it becomes fusiform in the beginning of anaphase revealing in this manner its dicentricity. In late anaphase it finishes by passing to one pole leaving in the other pole one of its kinetochores sometimes accompanied by a chromosomal fragment. 4) All the chromosomes divide transversely in both divisions, a diagram being enclosed to elucidate the question. 5) Spermatogonial chromosomes are provided with one kinetochore at each end, being curved toward the poles since the most beginning anaphase. 6) The following hypothesis is presented as an essay to explain the origin of microchromosomes: Since microchromosomes parallel sex chromosomes in most respects, as for instances in heteropycnosis and pairing modus, it seems highly probable that they originate from sex chromosomes. One may suppose that the ancestral form of a given species had a sex chromosome which used to lose a small centric fragment when it divided during meiosis. This fragment might well be at first an unstable one. Later, to compensate the effects of such a deficiency a mechanism arose through evolution which produced two useful results : a) the establishment of the fragment as a permanent structure of the cell nucleus and b) the acquirement by the sex chromosome of the faculty of passing to one pole without losing any of its ends.

No summary/description provided

No summary/description provided

No summary/description provided

Studying the spermatogenesis of Leptysma sp. and Leptysma dorsalis, the writer was able to observe primary spermatocytes in anaphase with the heterochromosome in precession, synchronism or succession, confirming in this way what was observed by Prof. Piza in several other species of Orthoptera.

Cephalocoema borellii (Giglio-Tos) has 19 chromosomes, that is 9 pairs of autosomes and a single heterochromosome, the latter having been observed either in succession or in synchronism as was the case of the two other species studied by Prof. PIZA, namely Cephalocoema zilkari Piza and Tetanorhynchus mendesi Piza. (= Cephalocoema sica Serv.).

1) In a former paper (4), the segregations of spiny versus spineless fruits was described as caused by one pair of mendelian factors, but in view of the possible pratical importance of spineless fruits a more detailed study was thought desirable. We may distinguish three main types of the distribuition of spine among the different varieties in our collections: Spineles fruits (inerms), found in a number of varieties. "Bald" fruits (a type called "careca" or bald owing to the irregular distribuition of the spines, which were always absent in some parts of the fruits while otrer patches might contain spines. Spiny fruits which may be classified into two or more groups, according to the number of regularly distributed spines. 2) The cross (spineless fruits) x (fruits with regularly distributed spines) HARLAND (7), PEAT (9) e FERNANDES (3) observed a 1:2:1 segregations in F2 while GURGEL (4) and DOMINGO (2) find it difficult to distinguish the homozygous and heterozygous spiny types without counting the number of spines. Such counts and the results of a detailed statistical analysis are now given. They show that the results of the 1:2:1 segregations are somewhat modified by both phenotypic modifications of the number of spines. The latter are caused by modifier genes introduced by both parents. 3) The cross between plants with a regular and an irregular distribuition of spines showed that the latter condition is due to the presence of two recessive complementary factors. Thus we have in F2, 15 regular to 1 irregular or partially "bald", and in back-crosses segregations in acordance with the ratio 3:1. 4) The cross spineless x "Careca", gave, as might be expected a trifatorial segregation in accordance with the following formula. "Inermes" "Careca" P : ss CalCal Ca2Ca2 x SS ca1ca1 ca2ca2 Fl : Ss CalCal Ca2Ca2 (with regularly distributed spines) F2 : 45 S- Cal- Ca2- (spines regularly distributed). 3 S- calca1 ca2ca2 ,"Careca) 16 ss ("inermes").

The present work is destinated to prove that the castes : workers and queens, in Melipona bees are due to genetic factors and not to differences in food. 2) Material used: Hives of Melipona quadri-fasciata anthidioides (Lep. 1836), M. schenki schenki (Gribodo, 1893), M. fasciata rufiventris (Lep. 1836), M. quadri-fasciata vicina (Lep. 1836), M. marginata marginata (Lep. 1836), Apis mellifera (L. 1758). 3) It should be pointed out that in Melipona bees there are no royal cells for the queens, but all the cells are of the same size independently of being destinated for workers, queens or drones. The numerous queens which are born are killed soon after emerging from their cells. 4) Changes of feeding in quality and in quantity caused no variation of castes. The only variable factor is the size, which becomes bigger when the bee is well nourished. 5) The offsprings of 5 hives were examined : 3 of M. quadri-fasciata anthidioides (n.o 1, n.o 2 and n.o 3), 1 of M. quadri-fasciata vicina (n.o 4) and 1 of M. marginata marginata (n.o 5). Combs of about 40 cells were taken into laboratory and the type of bee registered immediately after emerging. The results of the counts were: BOX COMB WORKER QUEEN PERCENTAGE Σ X2 to 12,5% Nº 1 1th 69 8 10,4% 0, 3139 " 1 2nd 144 18 11,1% 0, 2856 " 2 1th 52 8 13,3% 0, 0384 " 3 1th 45 10 18,2% 1, 6736 " 4 1th 56 4 6,7% 1, 8686 " 4 2nd 29 4 12,1% 0,00432 Σ X2 to 25% " 5 1th 34 14 29,2% 0,44444 "5 2nd 83 27 24,5% 0, 0121 In the 4 first boxes there is a percentage of 11,63% queens and in the last there is a percentage of 25,95%. 6) These percentages are very near two genetical ratios: 12,5% or 7:1, and 25% or 3:1, which correspond to a trifactorial and a bifactorial back-cross. Carrying out a X² test no significant deviations were found ( X² to 12,5% and to 25% and table 1 to 4). 7) We suppose that the formula for the queen in the first case (11,65%) is: AaBbCc. Since the Melipona bees are arrhenotokous hymenopteres, the drones are haploid and may have any one of the following eight formulas, corresponding to the gonic segregation of the queem : ABC, ABc, Abc, Abc, AbC, aBC, aBc, abC, abc. Anyone combination of these males with the queen will give a segregation of 7 workers to 1 queen, since there is always only one triple heterozygote among the eight possible segregates (table 5). 8) In order to explain the second case, it is suffient to assume that in this species there are only two pairs of factors, the queen being the double heterozygote : AaBb, while the drones may have any one of the following constitutions: AB, Ab, aB and ab. Workers are again all diploids which are homozygous for one or both factors, for instance: AABB, AABb, AaBB, aaBb, AAbb, etc. (table 6). 9) It is suggested that the genus Melipona is an intermediary type between the solitary bees, where all females are fertile independently of their feeding, and the genera Apis and Trigona, where without special feeding all females are born sterile, while only specially fed females develop into fertile queens. 10) No speculations are put forward with regards to the evolutionary mechanism which may have been responsible for the development of the genetical determination of castes in Melipona, since it seems advisable point to extend the studies to other insects with complicated caste systems.

A very simple method for calculating poultry balanced ration is reported in this paper. A table giving the crude protein composition of the common feeding stuffs at different weight used in the ration is included. The rules for using it is discussed, all calculation being restricted to addition an subtraction. The balanced rations are easily calculated and the use of the method is recommended to poultry keepers.

No summary/description provided

No summary/description provided

In this paper the author describes a very interesting case of union of two homologous chromosomes of the scorpion Tityus bahiensis just by the opposite extremities. The two normal pairs of chromosomes behave as ordinarily, the members of each pair showing at times a slight disturbance in their regular parallelism. The complex chromosome, on the contrary, behaves itself as if it were devoid of kinetochores, that is, it does not orient like normal chromosomes nor reveal any kind of active movement. The fusion of the chromosomes has resulted from terminal breakage at the opposite ends, the correspondig fragments having been found unpaired in a cell in which two pairs of chromosomes were present. Consequently, the compound chromosome, like the normal ones, is provided with a kinetochore at each one of the free ends. Being thus a centric chromosome its behavior, or more exactly, its kinetic inactivity may be compared with that of the monovalents found elsewhere in meioses. It is due o the failure of a partner. The fusion of two homologous chromosomes has transformed them into a new chromosomal unit in whose corresponding parts the ability of pairing was entirely abolished. This result is in full contradiction with the theory of a point-to point attraction between homologous chromosomes attributed to particular power of the genes, since, if genes really exist, being placed in their original loci, they would promote the union side by side of the members of the compound chromosome. If an attraction loci-to-loci should prevail the compound chromosome would be bent as in Fig. 8, C or form a ring similar to the loops observed in the inverted segment of sailvary chromosomes of Drosophila, as represented in the Fig. 8, D and this, in accordance with the order of the loci resulting from an union of corresponding or opposite ends of the fused chromosomes, as indicated in the Fig, 8 A and B. The evidence in hand points to a fusion by non homologous extremities. The expected rings, however, have never been found in metaphase plates. From this fact the author concludes that there is no point-to-point attraction between chromosomes, a conclusion in full agreement with the behavior of Hemipteran chromosomes which, in spite of geing composed of two equivalent halves do not bend in order to adjust the corresponding loci. (Cf. the papers on Hemiptera published by the author in this volume).

The Author concludes, in this contribution, the estudy he has been making since 1943, on the biological and ecological comportment of Apinagia Accorsii Toledo an of Mniopsis Glazioviana Warmg., Podostemonaceae wich are found attached to the rocks of Piracicaba Fall (Piracicaba, S. Paulo, Brazil). During the flood period, from October until March, the especies mentioned perform their vegetative development. Apigia Accorsii emittes stolons wich produce, laterally, rhizomes: besides, the still alive parts of the remaning rhizomes are regenerated. Mniopsis Glazioviana emittes hemicylindrical roots, the radicular buds of wich are capable of developing into new plants. For both especies, the germination of seeds may be effected in the following substrata : placents, capsules and pedicels of the fruits, vegetative residues and rhizomatic matter of Apinagia. Dehiscence of fruits takes place in contact with the air. Seeds adhere to the above mentioned substrata by means of a mucilage resulting from the transformation of its external tegument, in contact with water. The seedlings have no main root. A large number of root hairs develop around the hypocotyl; their function is fixation. The attachment of the plants to the rocks is made by means of root hairs and "haptera". The tranfer of young plants, which develop in the placents, capsules and fruits pedicels, etc., to the rocks takes place when they grow heavy enough as to bend the pedicels. The fruits and their parts contitute the best mean for the survining of the species in its habitat, for they are the only organs which stick to the rocks, after the complete destruction of the plant's bodies. The vegetative development is performed exclusively under water, while the floral cycle takes place as soon as the plants come in contact with the athmosphere, when they flower and fructiffy rapidly.

Particular aspects of the meiosis of two species of Hemiptera, namely Megalotomus pallescens (Stal) (Coriscidae) and Jadera sanguinolenta (Fabr.); (Corizidae) are described and discussed in this paper. Megalotomus pallescens This species has primary spermatocytes provided with 7 autosomal tetrads plus a single sex chromosome. The X is smaller than the autosomes and may be found either in the periphery of the circle formed by the autosomal tetrads or in the center together with the m-tetrad which always occupies this position. The X chromosome - In the primary spermatocytes this element, which is tetradiform, orients itself parallelly to the spindle axis and divides transversely by its median constriction. In the secondary spermatocytes it passes undivided to one pole. The m-chromosomes - These chromosomes have been frequently found in close association with the sex chromosome in nuclei wich have passed the diffuse stage, a fact which was considered as affording some evidence in support of the idea /developed by the present writer in another paper with regard to the origin of the m-chromosomes from the sex chromosome. Formation of tetrads - Tetrads appear at first as irregular areas of reticular structure, becoming later more and more distinct. Then, two chromosomal strands very loose and irregular in outline, connected whit each other by several transverse filaments, begin to develop in each area. Growing progressively shorter, thicker and denser, these strands soon give origin to typical Hemiptera tetrads. Jadera sanguinolenta Spermatogonia of this species have 13 chromosomes, that is, 10 autosomes, 2 m-chromosomes and one sex chromosome, one pair of autosomes being much larger than the rest. Chromosomes move toward the poles with both ends looking to them. Primary spermatocytes show 6 tetrads and a single X. The sex chromossome in the first division of the spermatocytes divides as if it was a tetrad, passing undivided to one pole in the second division. In the latter it does not orient, being found anywhere in the cells. Its most common situation in anaphase corresponds therefore to precession. Tetrads are formed here in an entirely different way : the bivalents as they become distinct in the nuclei which came out. of the diffuse stage they appear in form of two thin threads united only at the extremities, an aspect which may better be analized in the larger bivalent. Up from this stage the formation of the tetrads is a mere process of shortening and thickening of both members of the pair. Due to the fact that the paired chromosomes are well separated from each other throughout their entire lenght, the author concluded that chiasmata, if present, are accumulated at the very ends of the bivalents. If no chiasmata have been at all formed, then, what holds together the corresponding extremities must be a strong attraction developed by the kinetochores. If one interprets the bivalents represented in the figures 17-21 as formed by four chromatids paired by one of the ends and united by the opposite one, then the question of the diffuse attachment becomes entirely disproved since it is exactly by the distal extremities that the tetrads later will be connected with the poles. In the opinion of the present writer the facts referred to above are one of the best demonstration at hand of the continuity of the paired threads and at the same time of the dicentricity of Hemiptera chromosomes. In view of the data hitherto collected by the author the behavior of the sex chromosome of the Hemiptera whose males are of the XO type may be summarized as follows: a) The sex chromosome in the primary metaphase appears longitudinally divided, without transverse constriction. It is oriented with the extremities in the plane of the equator and its chromatids separate by the plane of division. (Euryophthalmus, Protenor). In the second division the sex chromosome, provided as it is with an active kinetochore at each end, orients itself with its lenght parallelly to the spindle axis and passes undivided to one pole (Protenor?), or loses to the other pole a centric end (Euryophthalmus) In the latter case it has to become dicentric by means of a longitudinal spliting beginning at the kinetochore. b) The sex chromosome in the primary metaphase is tetradiform, that is, it is provided with a longitudinal split and a median transverse constriction. Orients with its length paral lelly to the spindle axis (what is probably due to the kinetochores being not yet divided) and divides transversely. (Corizas hyalinus, Megalotomus pallescens). in the secondary metaphase the sex chromosome which turned to be dicentric in consequence of a longitudinal spliting initiated in the kineto chore, orients perpendicularly to the equatorial plane and without losing anyone of its extremities passes undivided to one pole (Megalotomus). Or, distending between both poles passes to one side, in which case it loses one of its ends to the other side. (Corizas hyalinus). c) The very short sex chromosome in the first division of the spermatocytes orients in the same manner aa the tetrads and divides transversely. In the second division, due to the inactivity o the inetochore, it remains monocentric and motionless anywhere in the cell, finishing by being enclosed in the nearer nucleus. In the secondary telophase it recuperates its dicentricity at the same time as the autosomal chromatids. (Jadera sanguinolenta, Diactor bilineatus). d) The sex chromosome in the first division orients in the equador with its longitudinal axis parallelly to the spindle axis passing integrally to one pole or, distending itself between the anaphase plates, loses one of its ends to the opposite pole. In this case it becomes dicentric in the prometaphase of the second division, behaving in this division as the autossomes. It thus divides longitudnally. (Pachylis laticomis, Pachylis pharaonis).

No summary/description provided

Two groups of 50 chicks each (100 grs. initial weight) were put into competition during 25 days to see whether or not the addition of 5% of charcoal in the feeds is benefical. At the end of the experiment, the average weight of the group which received charcoal was 174,9 grs., and of the control 262,2 grs., revealing the chicks of the latter better general appearance. This result shows the detrimental effect of the charcoal, but since mortality was greater in the group fed without it, a benefical effect of the charcoal in protecting weaker chicks against mortality may be admitted. This contentation, however, needs comprobations.

Beginning an experiment on protein comparisons, at the Poultry and Rabbitry Departament of the Esc. Sup. de Agricultura "Luiz de Queiroz", University of S. Paulo, four groups of growing chicks were submitted during 40 days to the following rations: basal part - 50 corn meal and 30 wheat bran, variable part - R1 - 10 tankage and 10 peanut meal, R2 - 10 tankage and 10 cottonseed meal, R3 - 7 peanut meal, 7 cocoanut meal and 7 cottonseed meal, R4 - 5 tankage, 5 peanut, 5 cocoanut and 5 cottenseed meal, R2 and R3 gave results which may be considered as equal and inferior than those obtained with the others, R4 being the best one. The statistical analises showed no significant differences.

The influence of cauliflower on egg laying was studied and the results obtained are reported by the authors in this paper. Twenty groups of ten chickens each were organized, eleven being of the Rhode Island Red and nine of the Light Sussez breed. Seven groups, including both breeds received feed on grazing and the cauliflower was given to all chickens during ten days. AH numerical data secured indicated that the number of eggs diminished during the treatment but the differences were not statistically significant. It is possible that a treatment with cauliflower during more days should be prejudicial but this, is the opinion of the authors, should not be of economical importance, since the chickens are supplied with by-products of cauliflower only during the crop season.