Cytogenetics of four Omophoita species (Coleoptera,Chrysomelidae, Alticinae): A comparative analysis using mitotic and meiotic cells submitted to the standard staining and C-banding technique

Omophoita belongs to the tribe Oedionychini and is endemic from Neotropical region. The species of the tribe Oedionychini have revealed certain singular chromosomal features, such as sex chromosomes with extremely large size, asynapsis, and synthelic or amphithelic orientation during meiosis. Additionally, some species also showed post-reductional segregation of the gigantic sex chromosomes in meiotic division. The purpose of this work was to characterize cytogenetically four Omophoita species (O. magniguttis, O. octoguttata, O. personata, and O. sexnotata) in relation to their diploid number, chromosomal morphology, type of sex chromosome system, and constitutive heterochromatin pattern in mitotic and meiotic cells, and compare the obtained data with those of related species to establish the mechanism involved in the chromosomal differentiation of these species during the evolutionary process. The diploid number, 2n = 22 = 20 + X + y, and meiotic formulae, 10II + X + y, observed in these species were similar to those of the same genus and other species related. The autosomal morphology was acrocentric in O. magniguttis and O. octoguttata, metacentric in O. personata, and predominantly metacentric in O. sexnotata. In all these species, the sex chromosomes were metacentric. The secondary constriction occurred in pair 6 and X chromosome of O. personata, and in pair 6 and y chromosome of O. sexnotata. The constitutive heterochromatin was pericentromeric in O. magniguttis and centromeric in O. sexnotata, with the exception of the mitotic sex chromosomes of O. sexnotata, in which centromeric C band was lacking. Additional C bands in the sex chromosomes of O. magniguttis and certain autosomes and sex chromosomes of O. sexnotata were observed. Collochores were indirectly identified in the spermatocytes of O. octoguttata, O. personata, and O. sexnotata. The main mechanisms involved in the karyotype evolution of these species were discussed.     

Different chromatin fractions of tomato (Solanum lycopersicum L.) and related species

Conventional chromosome staining has suggested that more than 75% of the tomato chromosomes are constituted by heterochromatin. In order to determine whether more deeply stained proximal regions are classic heterochromatin, the distributions of C-bands and chromomycin A₃ (CMA) bands, and the prophase condensation patterns, were analysed in tomato. In this and most other species of the tomato clade, the 5S and 45S rDNA sites were also localised. In tomato, CMA banding was similar to C-banding. After conventional staining, all species displayed large condensed heteropycnotic regions that did not correspond to C-bands or CMA bands. Analyses of the CMA banded karyotypes revealed a low heterochromatin content. Around 12–17% of the chromatin of tomato was CMA⁺ and 1/4 to 1/5 of this heterochromatin corresponded to 45S rDNA. In other species, the CMA⁺ heterochromatin showed extensive variation (8–35%), but was never near the values found in the literature for tomato. These data suggest the existence of three principal fractions of chromatin in tomato and related species: the late condensed euchromatin corresponding to the terminal regions of the chromosomes, the precocious condensed euchromatin that occupies the major part of the chromosomes and the constitutive heterochromatin that represents those regions revealed by C-bands.     

Ultrastructure of the mature testicular vesicle of Pseudonannolene tocaiensis Fontanetti, 1996 (Diplopoda, Pseudonannolenidae)

The mature testicular vesicles of the species Pseudonannolene tocaiensis have three portions: a peripheral portion; a central portion that is typically secretory and between these two an intermediary portion, a lumen filled with spermatozoa. Both secretory and peripheral portions present the same type of cells. The ultrastructural analysis of the peripheral portion suggests it is involved in hormone synthesis. The secretory portion probably contributes to the production of spermatic fluid, compensating for the absence of male accessory glands in this species.     

3D reconstruction and scanning electron microscopy of salivary glands of the millipede Rhinocricus padbergi (Verhoef, 1938) (Diplopoda: Spirobolida)

The three-dimensional technique applied to the salivary gland of the millipides Rhinocricus padbergi showed that it is a single structure, dorsolaterally located to the animal gut and composed of two distinct portion: an acinar and a tubular one. The last one opening onto the oral cavity. This work shows that the salivary gland in R. padbergi, although is a single body, it displays two excretory ducts (one in each side of the anterior end of the gut) which has the function of carrying out the secretion produced toward to the oral cavity, contrary to the anterior data registered by other authors who suggested that the salivary gland in diplopod animals would be a paired structures.     

Cytogenetics of the land snails Cantareus aspersus and C. mazzullii (Mollusca: Gastropoda: Pulmonata)

A cytogenetic study was carried out on the chromosomes and nuclear DNA contents of the land snails Cantareus aspersus and C. mazzullii (Gastropoda: Pulmonata). Chromosomes were studied using Giemsa staining, banding methods and fluorescent in situ hybridization (FISH) with three repetitive DNA probes [18S rDNA, (GATA)(n) and (TTAGGG)(n)]. Results were very similar in the two species both showing (1) 54 bi-armed chromosomes [submetacentrics (SM) + metacentrics (M) + subtelocentrics (ST)]; (2) 10 terminal NORs after sequential application of rDNA FISH and silver staining; (3) uniform DNA fluorescence with CMA(3) and DAPI staining and (4) genomic composition considerably enriched both in highly- and moderately-repeated DNAs. The telomeric (TTAGGG)(n) sequence hybridized with the termini of all of the chromosomes in the two species. In spite of their apparent karyological uniformity, flow cytometry DNA assays showed that C. aspersus and C. mazzullii are characterized by different nuclear DNA content (C values are 3.58 and 3.08 pg, respectively) and slightly different base composition in their genomes. Present data on GS and AT% in C. mazzullii and C. aspersus confirm the trend toward high GS values and GC percentages among land snails.     

Karyotype differentiation patterns in species of the subfamily Scarabaeinae (Scarabaeidae, Coleoptera)

The aim of this study was to describe the karyotype of species belonging to the subfamily Scarabaeinae (Coleoptera, Scarabaeidae) and to compile the conventional cytogenetic data available in the literature for this group. The karyotypes of ten species belonging to the tribes Canthonini, Coprini, Onthophagini and Phanaeini were analyzed by conventional staining. Eight of these species were described for the first time (Canthon aff carbonarius, Canthon chalybaeus, Coprophanaeus dardanus, Deltochilum aff amazonicum, Dichotomius geminatus, Oxysternon silenus, Phanaeus chalcomelas and Malagoniella aff astyanax) and two were redescribed (Diabroctis mimas and Digitonthophagus gazella) since their karyotypes differed from those previously published in the literature. Four species studied showed a diploid number of 2n = 20 and a parachute type sex determining system and the karyotype was 2n = 20,Xy in two species and 2n = 18,Xy_p, 2n = 19,X0, 2n = 12,XY and 2n = 14,neoXY in one each. The chromosome morphology of the different species varied, with the observation of metacentric, submetacentric, subacrocentric and acrocentric chromosomes. The X chromosome was predominantly meta or submetacentric in the species analyzed, whereas the y chromosome presented two arms or was punctiform. In conclusion, the subfamily Scarabaeinae comprises 120 species analyzed cytogenetically, and are observed the occurrence of five chromosome rearrangements (autosome–autosome and X-autosome fusions, pericentric inversions, fissions and loss of the y chromosome) that are related to the chromosome variability and evolution in the group.     

He(I) Photoelectron spectroscopy of transient species: fluorothiocyanate (FSCN)

Valence ionisation energies, obtained using He(Iα) photoelectron spectroscopy, of the hitherto unknown and unstable molecule FSCN are presented. Interpretation of the spectra is based on experimental considerations, correspondence with the spectra of related molecules, and the results of Hartree—Fock—Slater calculations using STF basis sets of double-zeta quality. The molecule is shown to exist in the thiocyanate form.     

The behaviour of carbon species produced by CO disproportionation on Ru(1, 1, 10) and Ru(001) surfaces

The behaviour of adsorbed CO on Ru(001) flat and Ru(l,1,10) stepped surfaces in the CO pressure range between 10^?6 and 10¹ Pa has been investigated by TDS, AES, LEED and UPS. The disproportionation of CO proceeds rapidly on the stepped surface and its apparent activation energy was obtained to be 20 kJ mol^?1 at nearly zero coverage. The carbon species produced by CO disproportionation show non-uniform reactivity with ¹⁸O₂ and provide four CO desorption peaks in TPR spectra, which are assigned to α-C¹⁸O,ß-C¹⁸O and those derived from carbidic and graphitic carbons. At smaller carbon coverage, only α-CO and β-CO were observed, but with increasing coverage the amount of ß-CO reaches a maximum and carbidic carbon is newly formed. Further increase of carbon deposition gives graphitic carbon. The conversion from carbidic to graphitic carbon and the dissolution into the bulk took place upon heating to 1000 K. It is remarkable that very active carbon species are converted to molecular CO through the reaction with O₂ even at low temperature such as 200 K. It was also confirmed that active carbon species are formed on Ru surface during COH₂ reaction.     

The early stages of three Palaearctic species of saproxylic hoverflies (Syrphidae, Diptera)

The third stage larva and puparium of the cerioidine hoverflies, Ceriana vespiformis (Latreille, 1804) and Sphiximorpha subsessilis (Illiger in Rossi, 1807) and the milesine, Spilomyia digitata (Rondani, 1865) (Diptera, Syrphidae) are described from specimens collected in the field. Ceriana vespiformis and S. digitata larvae were obtained from wet, decaying roots and tree holes of Fraxinus angustifolius L., respectively, in Spain and S. subsessilis from an exudation of sap on an Abies alba Miller tree in France.     

Minimization of SO(3) invariant Landau potentials for spin four

The absolute minima for the SO(3) invariant Landau potential for the nine-dimensional (spin-four) irreducible representation is discussed as a function of the coupling constants. The non-maximal D₄ stability group appears. This is studied in relation to Michel's conjecture.     

High vis-light photocatalytic property of g-C3N4 on four pollutants (RhB,MB, TC-HCl and P-Nitrophenol)

The g-C₃N₄ nanosheets were synthesized by a multistage program calcination with different heating rate, which was an easy, low-cost, and quick method. The morphology and structure of samples were characterized by various techniques. The performance evaluation of the samples was tested by degrading Rhodamine B, Methylene Blue, Tetracycline Hydrochloride and P-Nitrophenol in visible light. The results show that the photodegradation properties of TP-g-C₃N₄ prepared by multistage program calcination are the best than others. In particular, the degradation rate of TP-g-C₃N₄ to Rhodamine B reached 99.6% in just 4 min. TP-g-C₃N₄ catalyst has excellent stability and recycling performance. According to free radical capture experiments, •O₂⁻ may be the main active species for pollutant degradation. The possible photocatalytic degradation mechanism was also discussed. Due to the high specific surface area and a narrow band gap, the TP-g-C₃N₄ becomes a promising photocatalyst.     

Cortical diversity in three species groups of Parmotrema sensu lato (Parmeliaceae,lichenized Ascomycota)

Conventional techniques for structural studies under light microscope were employed to describe and compare the upper cortex anatomy in three species groups of Parmotrema sensu lato. This study indicates that there is a pattern in the structure of the upper cortex in all the three groups of Parmotrema species studied here, and this pattern can be used to place each species group separately within the genus Parmotrema. Although the species of Parmotrema studied have palisade prosoplectenchymatous upper cortex, there are clear differences between the analyzed groups. The upper cortex of Parmotrema s. str. can be characterized by more elongated cells and very compressed hyphae with small interstices between them; the upper cortex of the species with reticular maculae is characterized by the presence of maculae produced by the organization of hyphae that rise towards to the upper cortex and that are not so compressed, while the upper cortex of the species with dimorphic rhizinae has less elongated almost-rounded cells without interstices or cracks but is generally accompanied by aeroplectenchyma. Besides, the first cell layer of the upper cortex presents differential staining by toluidine blue and the epicortex is tightly attached to it.     

Cryopreservation of Centaurea ultreiae (Compositae) a critically endangered species from Galicia (Spain)

Ex situ conservation of endangered plants is an important aim in order to preserve biodiversity of flora in threatened ecosystems. Among the biotechnological techniques which can be used, cryopreservation is emerging as a preferred option in many instances. This study describes a cryopreservation technique developed for shoot tips of the endangered species Centaurea ultreiae (Compositae) using a vitrification procedure. Basal medium (BM) for preculture and loading phases consisted of 1/2 MS basal salts with modified vitamins (3 microM thiamine). For preculturing shoot tips, BM with five osmotic treatments were investigated: 0.3 M sucrose +/- 20 microM ABA, 0.6 M glycerol +/- 20 microM ABA and 0.25 M sucrose + 0.25 M glycerol + 10 microM ABA. A loading solution treatment (BM with 2 M glycerol and 0.4 M sucrose) was applied prior to exposure of shoot tips to PVS2 and found to be indispensable to obtaining successful post-LN recovery. Highest (95.5%) regrowth of LN immersed shoot tips was obtained following incubation on BM + 0.3 M sucrose + 20 microM ABA or 0.25 M sucrose + 0.25 M glycerol + 10 microM ABA, with loading treatment and PVS2 exposure for 20 minutes at 0 degree C. Keywords: cryopreservation, encapsulation, endangered species, ex situ conservation, vitrification.     

Homotopy algebras of differential (super)forms in three and four dimensions

We consider various \(A_{\infty }\)-algebras of differential (super)forms, which are related to gauge theories and demonstrate explicitly how certain reformulations of gauge theories lead to the transfer of the corresponding \(A_{\infty }\)-structures. In addition, for \(N=2\) 3D space, we construct the homotopic counterpart of the de Rham complex, which is related to the superfield formulation of the \(N=2\) Chern–Simons theory.     

Male reproductive system structure and accessory glands ultrastructure of two species of Triatoma (Hemiptera,Reduviidae, Triatominae)

Morphological studies in male reproductive system of insect, and accessory glands functions, can contribute to the knowledge of reproductive aspects in Triatominae. The present study aims to describe the structure of male reproductive system under scanning electron microscopy, and the ultrastructure of accessory glands during the process of maturation, in T. brasiliensis and T. melanica of different ages.These system consist of two testis, two vas deferens, two seminal vesicles, four pair of accessory glands and one ejaculatory duct. The four mesodermal male accessory glands of T. melanica and T. brasiliensis, present secretion storage in the firsts days of adult life in starved males. During the maturation process of male accessory glands of T. brasiliensis and T. melanica, granules with different sizes, shapes and electron density were seen. In T. melanica small vacuoles are released into the gland lumen in one-day-old males, however, after three and five days few granules are found in the cell cytoplasm. The secretory granules in T. brasiliensis increase in size and amount, in the five days old adult. The secretory pathway in the male accessory glands of the two species seems to be merocrine and apocrine suggesting that different substances are being produced at different times. The cell microvilli in T. brasiliensis are longer and narrower, these can be absent in some regions of the cell surface of T. melanica. Maturation of male accessory glands in the triatomine species studied occurred without adult blood meal. Its function can led to new insights for the comprehension of reproductive aspects in Triatominae.     

Molecular systematics and ultrastructural characterization of a forgotten species: Chattonidium setense (Ciliophora,Heterotrichea)

In the present paper we redescribe the ciliate Chattonidium setense Villeneuve 1937 combining morphological observations (live, stained, scanning, and transmission electron microscope) with behavioral notes and molecular data. Ultrastructural analysis revealed remarkable similarities between Chattonidium and representative members of the class Heterotrichea in cortical structure and cytoplasmic organization. The most similar genus for these aspects appears to be Condylostoma. To verify this relatedness, 18S rRNA genes from Chattonidium and from one Condylostoma species were sequenced. Phylogenetic analysis indicates Chattonidium belongs to the class Heterotrichea defined according to the modern taxonomy, and confirms its relatedness with Condylostoma already hypothesized by Villeneuve-Brachon (1940). The presence of the aboral cavity complex, a unique feature never described in other ciliates, and its peculiar organization revealed by ultrastructural analysis fully justify, in our opinion, the maintenance of Chattonidium in the separate family Chattonidiidae, established by Villeneuve-Brachon in 1940.     

The adsorption of molecular oxygen species on Ag(110)

The adsorption of oxygen on the Ag(110) surface was examined at temperatures down to 123 K. In addition to the dissociatively adsorbed state which desorbed at 590 K, a second oxygen state desorbed at 190 K following adsorption at 150 K and below. This high temperature state appeared to form prior to the development of the low temperature state. The ratio of coverages of the two states was a strong function of both exposure and adsorption temperature. Isotopic exchange experiments indicated that the low temperature state was molecularly adsorbed. The desorption of the molecularly adsorbed oxygen exhibited complex kinetics due to interaction with adsorbed oxygen atoms.     

Coordination of acetonitrile (CH3CN) to platinum (111): Evidence for an η2(C,N) species

Acetonitrile (CH₃CN) coordination to a Pt(111) surface has been studied with electron energy loss vibrational spectroscopy (EELS), XPS, thermal desorption and work function measurements. We compare data for the surface states with known acetonitrile coordination complexes. For CH₃CN adsorbed on Pt(111) at 100 K, the molecule is rehybridized and adsorbs with the CN bond parallel or slightly inclined to the surface plane in an η²(C, N) configuration. The ν(CN) frequency is 1615 cm^?1 and the C ls and N ls binding energies are 284.6 eV and 397.2 eV respectively. By contrast, weakly adsorbed multilayer acetonitrile exhibits a ν(CN) vibrational frequency of 2270 cm^?1, and C ls and N ls binding energies of 286.9 eV and 400.1 eV respectively. Both the EELS and XPS results are consistent with rehybridization of the CN triple bond to a double bond with both C and N atoms of the CN group attached to the surface. In addition to this majority η²(C, N) monolayer state, evidence is found for a second, more strongly bound minority molecular state in thermal desorption spectra. As a result of the low coverage of this state, EELS was unable to spectroscopically identify it and we tentatively assign it as an η⁴(C, N) species associated with accidental step sites. By contrast to the surface complexes, almost all of the known platinum-nitrile coordination complexes are end-bonded via the N lone-pair orbital. Several cases of side-on bonding are known, however, and we compare the results with the known complex Fe₃(η²-NCCH₃)(CO)₉. The difference in the coordinative properties of a Pt(111) surface versus a single Pt atom must be due to the increased ability of multi-atom arrays to back-donate electrons into the π¹ system of acetonitrile. Previously published EELS and XPS results for monolayer acetonitrile on Ni(111) and polycrystalline films are almost identical to the present results on Pt(111). We believe that the monolayer of $\text{CH}{}_3\text{CN}\text{Ni}\text{(111)}$ is also an η²(C, N) species, not an end-bonded species previously proposed by Friend, Muetterties and Gland.