Chromosome numbers in antlions (Myrmeleontidae) and owlflies (Ascalaphidae) (Insecta,Neuroptera)

A short review of main cytogenetic features of insects belonging to the sister neuropteran families Myrmeleontidae (antlions) and Ascalaphidae (owlflies) is presented, with a particular focus on their chromosome numbers and sex chromosome systems. Diploid male chromosome numbers are listed for 37 species, 21 genera from 9 subfamilies of the antlions as well as for seven species and five genera of the owlfly subfamily Ascalaphinae. The list includes data on five species whose karyotypes were studied in the present work. It is shown here that antlions and owlflies share a simple sex chromosome system XY/XX; a similar range of chromosome numbers, 2n = 14-26 and 2n = 18-22 respectively; and a peculiar distant pairing of sex chromosomes in male meiosis. Usually the karyotype is particularly stable within a genus but there are some exceptions in both families (in the genera Palpares and Libelloides respectively). The Myrmeleontidae and Ascalaphidae differ in their modal chromosome numbers. Most antlions exhibit 2n = 14 and 16, and Palparinae are the only subfamily characterized by higher numbers, 2n = 22, 24, and 26. The higher numbers, 2n = 20 and 22, are also found in owlflies. Since the Palparinae represent a basal phylogenetic lineage of the Myrmeleontidae, it is hypothesized that higher chromosome numbers are ancestral for antlions and were inherited from the common ancestor of Myrmeleontidae + Ascalaphidae. They were preserved in the Palparinae (Myrmeleontidae), but changed via chromosomal fusions toward lower numbers in other subfamilies.     

The lichenicolous species of Odontotrema (syn. Lethariicola) (Ascomycota,Ostropales)

Abstract:The genus Lethariicola is shown to be a synonym of Odontotrema. Fifteen lichenicolous species are recognized: O. bryoriae sp. nov. (on Bryoria), O. cuculare comb. nov. (on Parmeliopsishyperopta), O. figulinum comb. nov. (on Lecanorapolytropa), O. intermedium sp. nov. (on Thamnolia), O. lecanorae sp. nov. (on Lecanora), O. melaneliae sp. nov. (on Melanelia), O. ochrolechiae sp. nov. (on Ochrolechia), O. pertusariae sp. nov. (onPertusariahymenea ), O. rhizocarpicola sp. nov. (on Rhizocarpon), O. santessonii sp. nov. (on Thamnolia), O. sipei comb. nov. (on Letharia), O. thamnoliae sp. nov. (onThamnolia ), and three undescribed species on Lecanora, Mycoblastus and Usnea. The type ofO. cuculare has two distinct lichenicolous species of Odontotrema, and the name is lectotypified on the species growing on Parmeliopsis. A key is given to all lichenicolous species of Odontotrema andParalethariicola .     

Hydrotris(1-pyrazolyl)borates of chromium(III)

The preparation and characterization of dichloro- (hydrotris(1-pyrazolyl)borato)pyridinechromium(III), CrCl₂(HB(PYZ)₃)Py, (Py = pyridine and HB(PYZ)₃^-1 is the hydrotris(1-pyrazolyl)borato anion) is described. The structure of the compound was determined by single crystal X-ray diffraction. Crystals were monoclinic, P2₁/c, a = 11.603(2), b = 9.845(1), c = 16.095(2) Å, β = 96.04(1)° with four formula units in the unit cell. Intensities were measured on a Nicolet P3 diffractometer with use of Mokα radiation. The structure was solved by standard methods and refined to R₁ = 0.0601, R₂ = 0.0397 based on 3142 independent reflections. Bond lengths and angles are normal. The pyridine molecule is oriented such that the plane bisects the angle between the two cis pyrazole rings. The synthesis and preparation of the related Cr(III) species CrCl₂(HB(PYZ)₃)pyrazole, Ph₄As[CrCl₃HB(PYZ)₃] and [Cr(HB(PYZ)₃)₂]PF₆ are described and the evaluation of the CrCl₂(HB(PYZ)3)L (L = pyridine or pyrazole) species for genotoxicity is discussed.     

Electronic structures of collagen model polymers: (Gly-Pro)n, (Gly-Hyp)n, (Ala-Pro)n, (Ala-Hyp)n, (Gly-Pro-Gly)n, (Gly-Hyp-Gly)n, (Gly-Pro-Pro)n, and (Gly-Pro-Hyp)n

In order to investigate the relationship existing between the electronic structures of collagen and its biochemical functions in vivo, the semiempirical CNDO/2 SCF MO calculations were carried out on several model polymers of collagen, (Gly-Pro)_n, (Gly-Hyp)_n, (Ala-Pro)_n, (Ala-Hyp)_n, (Gly-Pro-Gly)_n, (Gly-Hyp-Gly)_n, (Gly-Pro-Pro)_n and (Gly-Pro-Hyp)_n. Geometries of the skeleton of these polymers were assumed to be the same as those of poly(l-proline) I (cis) and II (trans) and the calculations were performed only on infinite polymers in a single chain. The results show that the cis form is always more stable than the trans form for all the polymers treated. This energy difference between the cis and trans forms depends, for example, on the kind of amino acid residue, Gly or Ala, but this could not be seen in the Pro or Hyp residue. The flexibility or mobility of the collagen structure was explained using the energy difference between the cis and trans forms of the polymers, i.e. the cis-trans conversion of the collagen was discussed in connection with the energy difference. The reason why the collagen has the constitution of (Gly-Pro-Hyp)_n is briefly discussed.     

Synthesis and structure of chloro(ligand)bis(diphenylglyoximato)cobalt(III) complexes

The synthesis and characterization of trans-chloro- (ligand)bis(diphenylglyoximato)cobalt(III) complexes [ligand = pyridine (py), α-, β-, or γ-picoline (α-pic, β-pic, γ-pic), 3,5-lutidine (lut), p-toluidine (p-tol) and PPh₃] is presented. X-ray crystal structure determination of the pyridine (1) and p-toluidine (6) derivatives has been carried out. Compound 1 crystallizes in the monoclinic system, space group P2₁/n, with Z = 4 and unit cell parameters a = 23.124(4), b = 13.009(3) and c = 11.204(3) Å, and β= 93.14(2)°. Compound 6 crystallizes in the monoclinic system, space group P2₁/n, with Z = 4 and unit cell parameters a = 18.792(3), b = 12.540(2) and c = 15.346(3) Å, and β = 97.54(2)°.     

Revision of the green lacewing subgenus Ankylopteryx (Sencera) (Neuroptera,Chrysopidae)

The Australasian and Oriental green lacewing subgenus Ankylopteryx (Sencera) Navás (Chrysopinae: Ankylopterygini) is examined and its diversity and placement among other members of the tribe Ankylopterygini is discussed. After study of specimens spanning the full distribution and anatomical range of variation for the subgenus, all prior putative species, resulting in the sole valid species are newly synonymized, Ankylopteryx (Sencera) anomala (Brauer). Accordingly, the following new synonymies are established: Sencera scioneura Navás, syn. n., Sencera feae Navás, syn. n., and Sencera exquisita Nakahara, syn. n. [all under the name Ankylopteryx (Sencera) anomala]. A lectotype is newly designated for Ankylopteryx (Sencera) anomala so as to stabilize the application of the name. To support our hypotheses, the wing and general body coloration as well as the male genitalia are reviewed. We elaborate on the possibility of Ankylopteryx (Sencera) anomala being nothing more than an autapomorphic species of Ankylopteryx Brauer, as it was originally described. The species is not sufficiently distinct to warrant recognition as a separate subgenus within the group, and most certainly not as its own genus as has been advocated by past authors. Nonetheless, we do not for now go so far as to synonymize the subgenus until a more extensive phylogenetic analysis is undertaken with multiple representative species from across Ankylopteryx and other ankylopterygine genera. Lastly, we comment on the biology of Ankylopteryx (Sencera) anomala in terms of the attraction of males to methyl eugenol and on the widespread practice of splitting within Chrysopidae.     

Preparation and structure of bis(trifluoroacetato)dicarbonyl bis(triethylphosphine)molybdenum(lI)

The Mo(CO)₂(PEt₃)₂(CF₃COO)₂ complex, obtained by prolonged reaction of trifluoroacetic acid with Mo(CO)₃(PEt₃₎₃ in dichloromethane, was characterized by spectroscopic methods and by X-ray crystal structure determination. The crystals belong to the monoclinic space group Cc, with a = 20.037, b = 10.879, _c = 15.176 Å,β/3 = 129.28° and _Z = 4. The structure was refined on 2135 observed reflections to R = 0.047. The Mo(II) atom is 7-coordinated and has a capped trigonal prism geometry, the capping position being occupied by a monodentate CF₃CO₂ ligand. The quadrangular plane contains one CO, one PEt₃ and one bidentate CF₃CO₂ ligand. The remaining CO and PEt₃ molecules are found on the opposite edge.     

Kinetic properties of phosphoenolpyruvate carboxylase from c(3), c(4), and c(3)-c(4) intermediate species of flaveria (asteraceae)

Flaveria cronquistii (C₃), F. chloraefolia (C₃-C₄), F. floridana (C₃-C₄), F. pubescens (C₃-C₄), F. anomala (C₃-C₄), F. linearis (C₃-C₄), F. brownii (C₄), F. palmeri (C₄), F. trinervia (C₄) and F. australasica (C₄), comprising 10 out of the 21 known species of the genus Flaveria (Asteraceae), were included in a comparative study of the kinetic and regulatory properties of green leaf phosphoenolpyruvate (PEP) carboxylase. At least three kinetically distinct enzyme-forms were identified on the basis of their affinities for PEP and the degree of allosterism with respect to this substrate. The kinetic properties of PEP carboxylase of most of the species seemingly were modified in vivo depending on the growth conditions of the plants. K_m(PEP_free)-values of the enzyme from the five C₃-C₄ intermediate species ranged from 6 micromolar (F. chloraefolia, low light-grown) to 38 micromolar (F. pubescens, high light-grown). In contrast, the K_m for PEP of PEP carboxylase from the C₃ species F. cronquistii (13 micromolar) apparently was not influenced by growth conditions. The response of the enzyme from the C₃ and C₃-C₄ species was hyperbolic in all cases. A second isoform with a lower affinity for PEP (88-100 micromolar), but also hyperbolic kinetics was found in the C₄ species F. brownii, whereas in the three other C₄ species examined a PEP carboxylase with a still lower affinity for PEP (187-221 micromolar) and sigmoidal kinetics was present. These isozyme-related kinetic data were supported by analyses of the elution behavior of the enzyme during anion-exchange chromatography on DEAE-Trisacryl M. The results are discussed with respect to the evolution of C₄ photosynthesis in the Flaveria genus.     

Egg parasitoids (Hymenoptera: Mymaridae) of Amrasca biguttula (Ishida) (Hemiptera: Cicadellidae) on Okinawa Island,a pest of okra in Japan

The fairyfly Anagrus (Anagrus) japonicus Sahad (Hymenoptera: Mymaridae) is identified for the first time as an egg parasitoid of the okra leafhopper Amrasca (Sundapteryx) biguttula (Ishida) (Hemiptera: Cicadellidae) on Okinawa Island, Japan. Amrasca biguttula is a serious pest of okra, Abelmoschus esculentus (L.) Moench (Malvaceae), both in Okinawa and Bonin Islands. Female of A. japonicus is redescribed, and its previously unknown male is described, based on the reared specimens from Okinawa. Prior to this study, host associations of A. japonicus were unknown. Another species of Mymaridae, Arescon enocki (Subba Rao and Kaur), also emerged from eggs of A. biguttula on okra in Okinawa, albeit in much smaller numbers.     

Taxonomic notes on some advanced Tournaisian (Mississippian) siphonodellids (Conodonta)

Traditionally, biostratigraphy of the terminal Famennian (Upper Devonian) and lower part of the Tournaisian (Mississippian) is based on phylogeny of the conodont genus Siphonodella Branson and Mehl. This study is focused on a Siphonodella species with a long taxonomical history. For the last three decades it was known as S. hassi Ji, 1985 and was used as a zonal index for the eponymic hassi Zone, used worldwide. However, this species faces several taxonomical problems. The main issue is the homonymy of S. hassi and S. cooperi hassi Thompson and Fellows, 1970. However, S. cooperi hassi is a subjective junior synonym of S. obsoleta Hass, 1959. The oldest junior synonym of S. hassi is S. wilberti Bardasheva, Bardashev, Weddige and Ziegler, 2004, and, according to a statement by the International Commission on Zoological Nomenclature, the latter represents the only available name for this species. An additional problem is the similar morphology of early ontogenetic stages of S. wilberti and S. quadruplicata Branson and Mehl, 1944, the youngest stratigraphically important siphonodellid species. In advanced ontogenetic stages, P₁ elements that possess two rostral ridges belong to S. wilberti only. The smaller P₁ elements having two or less rostral ridges comprise the S. wilberti- S. quadruplicata plexus. Maintenance of the wilberti Zone in the Tournaisian global zonation is suggested.     

Preparation and characterization of (9-methyladenine)triammineplatinum(II) and trans-dihydroxo(9-methyladenine)triammineplatinum(IV) complexes

The preparation is reported of [(NH₃)₃Pt(9- MeA)] X₂ (9-MeA = 9-methyladenine) with XCl (1a) and XClO₄ (1b) and of trans-[(OH)₂Pt(NH₃)₃- (9-MeA)]X₂ with XCl (2a) and XClO₄ (2b), and the crystal structure of 1b. [(NH₃)₃Pt(C₆H₇N₅)](ClO₄)₂ crystallizes in space group P2₁/n with a = 20.810(7) Å, b = 7.697(3) Å, c = 10.567(4) Å, β = 91.57(6)°, Z = 4. The structure was refined to R = 0.054, R_w = 0.063. In all four compounds Pt coordination is through N7 of 9-MeA, as is evident from ³J coupling between H8 of the adenine ring and ¹⁹⁵Pt. Pt(II) and Pt(IV) complexes can be differentiated on the basis of different ³J values, larger for Pt(II) than for Pt(IV) by a factor of 1.57 (av). In Me₂SO-d₆, hydrogen bonding occurs between Cl^? and C(8)H of 9-MeA as weil as between Cl^? and the NH₃ groups in the case of the Pt(II) complex 1a. Protonation of the 9-MeA ligands was followed using ¹H NMR spectroscopy and pK_a values for the N1 protonated 9-MeA ligands were determined in D₂O. They are 1.9 for 1a and 1.8 for 2a, which compares with 4.5 for the non-platinated 9-MeA. Possible consequences for hydrogen bonding with the complementary bases thymine or uracil are discussed briefly. Protonation of the OH groups in the Pt(IV) complexes has been shown not to occur above pH 1.     

Crystal structures of α- and β-(1,10-phenanthroline)tetrahydroborato(triphenylphosphine)copper(I) and (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline)tetrahydroboratocopper(I)

Copper(I) is five coordinate in (1,10-phenanthroline)tetrahydroborato(triphenylphosphine)copper(I). This compound crystallizes from either toluene as the yellow, α-form, a = 16.247(8), b = 9.750(7), c = 9.322(5) Å, α = 62.92(4), β = 84.77(4), γ = 84.34(5)°, triclinic P$\text{1}$, Z = 2, or from a xylene/methylene chloride mixture as the red β-form, X-ray cell, a = 13.675(11), b = 10.115(8), c = 9.700(7) Å, α = 95.22(6), β = 96.22(6), γ = 101.02(6)°; neutron cell, as the tetradeuteroborate, a = 13.703(1), b = 10.096(8), c = 9.74(1) Å, α = 95.23(9), β = 96.51(8), γ = 101.04(2)°, triclinic, P$\text{1}$, Z = 2. For both forms, unidentate triphenylphosphine, bidentate 1,10-phenanthroline and unsymmetrical bidentate BH₄^? completes the copper(I) coordination but there are subtle differences between the two. When the ligand 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, dmdp, replaces 1,10-phenanthroline, the compound obtained is four coordinate with no tpp in the crystal. [C(dmdp)BH₄] is monoclinic, Cc, a = 14.522(4), b = 20.07(2), c = 7.718(2) Å, β = 106.17(2)°, Z = 4.     

Isothiocyanatotriphenyl(pyridinium-2-carboxylato)tin(IV) monohydrate

The crystal structure of isothiocyanatotriphenyl- (pyridinium-2-carboxylato)tin(IV) monohydrate is reported. The crystals are monoclinic, space group P2₁/n, a = 10.349(2), b =12.003(2), c = 19.325(4) Å, β = 97.68(2)°, Z = 4, refined to R_F = 0.024 on 4249 observed reflections.The tin(IV) atom is five-coordinate, being bound to three phenyl groups, the isothiocyanato nitrogen atom and an oxygen from the picolinic acid. The geometry around the tin atom is trigonal bipyramidal, with the three phenyl groups occupying the equatorial positions, while the picolinic acid oxygen and the isothiocyanato nitrogen are coordinated axially. The acidic proton of picolinic acid has shifted position in the complex, and is bound to the heterocyclic nitrogen atom. The acid is thus coordinated in the form of a zwitterion. These trigonal bipyramidal units are linked together as dimers by pairs of water molecules, each of which hydrogen- bonds to the non-coordinated carboxylate oxygen atoms of both picolinic acid molecules, plus the heterocyclic nitrogen atom of one picolinic acid molecule. For complex formation with the protonated acid, theheterocyclic nitrogen should be alpha to the carboxylic acid group.     

Centipede (Chilopoda) richness and diversity in the Bug River valley (Eastern Poland)

The main aim of the survey was to describe the diversity and richness of Chilopoda in the selected area of the Bug River valley. The study sites were located in two regions differing in the shape of the valley, the presence of thermophilous habitats and the size of riparian forests. Pitfall traps were used as a sampling method. As a result, 444 specimens belonging to 12 centipede species of two orders – Geophilomorpha (four species) and Lithobiomorpha (eight species) were caught. Lithobius (Monotarsobius) curtipes C.L.Koch, 1847, Pachymerium ferrugineum (C.L.Koch, 1835), Lamyctes (Lamyctes) emarginatus (Newport, 1844) and Lithobius (Monotarsobius) dudichi Loksa, 1947 were the most common and the most numerous species. Of particular note is Lithobius dudichi found in Poland for the first time and previously known based on a single specimen. Two to 10 Chilopoda species were found in each habitat under investigation. The greatest species richness was found in thermophilous thickets (10 species), sandy grasslands (eight), xerothermic grasslands (eight) and mesic meadows (six). The fewest number of species (two) was found in rushes at oxbows and in wet meadows. We found differences in the species composition and the number of Chilopoda between the lower (102 specimens, six species) and the middle (324 specimens, 11 species) section of the river valley. Our results confirm the need to protect xerothermic habitats, unique almost throughout entire Central Europe, which due to their distribution and their small area covered are fairly easily subject to the process of destruction.     

The crystal and molecular structure of O-ethylxanthato-bis(quinolin-8-olato)antimony(III) and a redetermination for tris(O-ethylxanthato)antimony(III)

The crystal structures of the title compounds Sb(C₉H₆NO)₂(S₂COC₂H₅) (1) and Sb(S₂COC₂H₅)₃ (2) have been determined by three dimensional X-ray diffraction techniques and refined by a least squares method; final R 0.049 for 2911 reflections [I ? 3σ(I)] for (1) and R 0.047, R_w 0.046 for 846 reflections [I ? 2σ(I)] for (2). Crystals of (1) are triclinic, space group P1, a = 10.825(2), b = 11.131(2), c = 8.911(1) Å, α = 109.45(1), β = 95.92(1) and γ = 93.02(1)° with Z = 2. Crystals of (2) are rhombohedral, space group R$\text{3}$, a_rhomb = 10.138(3) Å and α = 103.43(2)°. The environment of the Sb atom in (1) is based on a pentagonal bipyramidal geometry consisting of the six donor atoms of the three chelating ligands and a stereochemically active lone-pair of electrons which occupies the remaining axial position. The xanthate ligand chelates the Sb atom almost symmetrically with two long SbS bonds of 3.059(2) and 3.171(2) Å. In contrast the xanthate ligands in (2) chelate the Sb atom with asymmetric SbS bonds of 2.511(2) and 3.002(3) Å.     

Development of Neoseiulus womersleyi (Schicha) and Euseius ovalis (Evans) feeding on four tetranychid mites (Acari: Phytoseiidae,Tetranychidae) and pollen

The development of the predatory mites, Neoseiulus womersleyi (Schicha) and Euseius ovalis (Evans), feeding on four tetranychid mites (Tetranychus urticae, Tetranychus kanzawai, Oligonychus mangiferus, Panonychus citri), maize pollen or Chinese loofah pollen was studied at 25 °C. Immature stages of N. womersleyi feeding on T. urticae and T. kanzawai had shorter developmental duration (4.71 and 5.02 days for females, 4.77 and 5.19 days for males, respectively) than those feeding on other food sources. Immature stages of E. ovalis females feeding on O. mangiferus and T. urticae developed in 4.99 and 5.13 days, respectively, the shortest developmental duration measured. Immature stages of E. ovalis males feeding on O. mangiferus and T. urticae developed in 5.12 and 5.37 days, respectively. The longevity of N. womersleyi males (13.31 to 14.51 days) and females (17.67 to 21.81 days) feeding on T. urticae, T. kanzawai or maize pollen was longer than the longevity of N. womersleyi feeding on O. mangiferus, P. citri or loofah pollen. E. ovalis males (12.91 to 16.74 days) and females (16.24 to 23.77 days) feeding on O. mangiferus, T. urticae or maize pollen lived longer than E. ovalis males and females feeding on T. kanzawai, P. citri or loofah pollen.     

Different sperm number in the spermatophores of Orchesella villosa (Geoffroy) (Entomobryidae) and Allacma fusca (L.) (Sminthuridae)

Members of the basal hexapod group Collembola perform indirect sperm transfer; males deposit spermatophores on the soil and these are then picked up by females for insemination. Orchesella villosa exhibits a dissociated mating behavior, while Allacma fusca has either associated mating behavior or, more commonly, produces spermatophores without pairing. Sperm ultrastructure in the two species has been studied by TEM and SEM observations to estimate the volume of these cells. The sperm number into each spermatophore has been determined by counting the fluorescent nuclei after Hoechst staining of sperm droplets squash preparations. Sperm droplets at the apex of spermatophores contain numerous spermatozoa of typical appearance, wound up and with a long anterior appendage (peduncle). Sperm droplets of Orchesella villosa are smaller (about 10 times) than in A. fusca, however they contain substantially more sperm cells (about three times). These differences could be explained as follows: (a) sperm of O. villosa are shorter than those of A. fusca (58 and 107 μm, respectively) and thus the volume of a single sperm of O. villosa is about 10 times smaller than in A. fusca; (b) considering the volume of sperm droplets and of sperm cells, the estimated number of sperm cells would be higher in A. fusca than in O. villosa; and (c) the conspicuous reduction of the sperm cells observed in A. fusca is likely linked to the aberrant meiosis present in this species, as well as in all Symphypleona studied so far, that causes a loss of 50% of their sperm.     

Comparative RFLP mapping of the chlorotoluron resistance gene (Su1) in cultivated wheat (Triticum aestivum) and wild wheat (Triticum dicoccoides)

Chlorotoluron is a selective phenylurea herbicide widely used for broad-leaved and annual grass weed control in cereals. Variation in the response to chlorotoluron (CT) was found in both hexaploid bread wheat (Triticum aestivum L.) and wild tetraploid wheat (Triticum dicoccoides KöRN.). Here, we describe the comparative mapping of the CT resistance gene (Su1) on chromosome 6B in bread and wild wheat using RFLP markers. In bread wheat, mapping was based on 58 F₄ single-seed descent (SSD) plants of the cross between a genotype sensitive to chlorotoluron, ‘Chinese Spring’ (CS), and a resistant derivative, the single chromosome substitution line, CS (‘Cappele-Desprez’ 6B) [CS (CAP6B). In T dicoccoides, mapping was based on 37 F₂ plants obtained from the cross between the CT-susceptible accession B-7 and the resistant accession B-35. Nine RFLP probes spanning the centromere were chosen for mapping. In bread wheat Su1 was found to be linked to α-Amy-1 (9.84 cM) and Xpsr371 (5.2 cM), both on the long arm of 6B, and Nor2 (2.74 cM) on the short arm. In wild wheat the most probable linkage map was Nor2-Xpsr312-Su1-Pgk2, and the genetic distances between the genes were 24.8cM, 5.3cM, and 6.8cM, respectively. These results along with other published map data indicate that the linear order of the genes is similar to that found in T. aestivum. The results of this study also show that the Su1 gene for differential response to chlorotoluron has evolved prior to the domestication of cultivated wheat and not in response to the development and use of chemicals.     

Combined Genotoxic Effects of a Polycyclic Aromatic Hydrocarbon (B(a)P) and an Heterocyclic Amine (PhIP) in Relation to Colorectal Carcinogenesis

Colorectal neoplasia is the third most common cancer worldwide. Environmental factors such as diet are known to be involved in the etiology of this cancer. Several epidemiological studies have suggested that specific neo-formed mutagenic compounds related to meat consumption are an underlying factor involved in the association between diet and colorectal cancer. Heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) are known mutagens and possible human carcinogens formed at the same time in meat during cooking processes. We studied the genotoxicity of the model PAH benzo(a)pyrene (B(a)P) and HCA 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), alone or in mixture, using the mouse intestinal cell line Apc^Min/+, mimicking the early step of colorectal carcinogenesis, and control Apc^+/+ cells. The genotoxicity of B(a)P and PhIP was investigated using both cell lines, through the quantification of B(a)P and PhIP derived DNA adducts, as well as the use of a genotoxic assay based on histone H2AX phosphorylation quantification. Our results demonstrate that heterozygous Apc mutated cells are more effective to metabolize B(a)P. We also established in different experiments that PhIP and B(a)P were more genotoxic on Apc^Min/+ cells compared to Apc^+/+. Moreover when tested in mixture, we observed a combined genotoxicity of B(a)P and PhIP on the two cell lines, with an increase of PhIP derived DNA adducts in the presence of B(a)P. Because of their genotoxic effects observed on heterozygous Apc mutated cells and their possible combined genotoxic effects, both B(a)P and PhIP, taken together, could be implicated in the observed association between meat consumption and colorectal cancer.     

Predation rates of Neoseiulus womersleyi (Schicha) and Euseius ovalis (Evans) feeding on tetranychid mites (Acari: Phytoseiidae,Tetranychidae)

Predation rates of Neoseiulus womersleyi and Euseius ovalis feeding on eggs, larvae, or protonymphs of Tetranychus urticae, Tetranychus kanzawai, or Oligonychus mangiferus were measured in a chamber at 25 °C. N. womersleyi immatures consumed 9.73 T. urticae eggs, 13.53 larvae, or 11.57 protonymphs, while gravid females consumed 12.13 T. urticae eggs, 14.37 larvae, or 12.07 protonymphs daily. Female N. womersleyi consumed a total of 218.12 T. urticae eggs, 260.85 larvae, or 222.33 protonymphs, while male N. womersleyi consumed a total of 96.39 T. urticae eggs, 112.23 larvae, or 99.65 protonymphs. When O. mangiferus larvae or protonymphs were offered to E. ovalis, immatures consumed 18.57 larvae or 17.47 protonymphs. Gravid females consumed 16.83 larvae or 12.83 protonymphs daily, with a total of 330.68 larvae or 252 protonymphs. Adult E. ovalis males consumed fewer O. mangiferus larvae (107.69) or protonymphs (91.51) than females. Conversion rate of predation to reproduce was expressed as “Food–reproduction exchange rate” of N. womersleyi was lower on T. urticae than on T. kanzawai. E. ovalis showed a higher food–reproduction exchange rate on O. mangiferus than on T. urticae. The results suggest that N. womersleyi and E. ovalis feed mainly on larvae and protonymphs rather than on the eggs of T. urticae, T. kanzawai, and O. mangiferus. We recommended using T. urticae eggs are suitable food for mass rearing for both N. womersleyi and E. ovalis.