A Cytogenetic Study of the Leaf Beetle Genus Cyrtonus (Coleoptera, Chrysomelidae)

The chromosomes of ten species of Cyrtonus and the genome sizes of six are surveyed. Among the total of 15 chromosomally studied species, 11 have 2n=28 chromosomes and a 13+Xy_p male meioformula, three have 2n=40 and 19+Xy_p and one 2n=46 and 22+Xy_p. All but one species with 28 chromosomes show only metacentric or submetacentric chromosomes, whereas the species with 40 and 46 chromosomes display some telocentrics or subtelocentrics, that are probably derived from the former by centric fissions. However, since the number of major chromosome arms is strikingly higher in these latter species (NF=70 and 78) than in the 28-chromosome species (mostly NF=56), other chromosomal rearrangements such as pericentric inversions or heterochromatin accretions could also be involved. The genome sizes display a narrow range, from 1C=0.6–1.22pg, and they are not significantly correlated with the chromosome numbers. Some possible factors implied in the rough chromosomal evolution of Cyrtonus are discussed in relation to a few other genera of the subfamily Chrysomelinae.     

Flexibility on the karyotype evolution in bitterlings (Pisces, Cyprinidae)

In bitterlings (Acheilognathinae) C- and Ag-banding karyotypes of 6 species-subspecies collected in China and South Korea were analyzed. The chromosomal constitution of 2n=46 (4SM+42ST) in Rhodeus atremius fangi was quite different from that of 2n=48 (8M+20SM+20ST) in other species-subspecies in Rhodeus. It was concluded from the analysis of banded chromosomes that the increase in number of ST during the karyotype change from 2n=48 to 2n=46 was achieved by a series of pericentric inversions from 24 M-SM to 24 ST, and the decrease in the diploid number was caused by an additional tandem fusion of 4 ST chromosomes, forming a new ST pair in the 2n=46 karyotype. The karyotype of Tanakia koreensis, T. signifer, and Acheilognathus macropterus is 2n=48 (8M+20SM+20ST), 2n=48 (8M+20SM+14–16ST+4–6 A), 2n=44 (14M+16SM+14ST), respectively. In R. ocellatus ocellatus, T. koreensis, T. signifer and A. macropterus, karyotype changes from 2n=48 to 2n=44 due to centric fusion and inversion have also been estimated. It was suggested that C-banding heterochromatin was greatly concerned with the karyotype evolution in bitterlings.     

Genetic variation in the subunits of globulin-1 storage protein of French bean

Summary Charge and molecular weight heterogeneity of globulin-1 (G1) polypeptides of the bean, Phaseolus vulgaris L., were revealed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Different bean cultivars were classified into three groups: Tendergreen, Sanilac, and Contender on the basis of their protein subunit composition. Nine distinct major bands: 51,49, 48.5,48^T, 48^S, 47, 45.5, 45^S, and 45^C, and two minor bands: 46^T and 46^S were found to account for the three profiles seen on one-dimensional SDS-PAGE. Two-dimensional analysis revealed these eleven protein bands to be composed of a minimum of fourteen distinct protein subunits. The Tendergreen and Sanilac types differ in their G1 polypeptide composition. The protein patterns of the Contender types are intermediate, containing many protein subunits found in the patterns of the Tendergreen and Sanilac types suggesting a genetic and evolutionary relationship.     

(T2AG3)n Telomeric Sequence Hybridization Indicating Centric Fusion Rearrangements in the Karyotype of the Rodent Oryzomys Subflavus

Chromosome preparations of 30 specimens of Oryzomys subflavus trapped in eight Brazilian localities were C-, and G-banded and analyzed by fluorescence in situ hybridization (FISH). Two karyotypes were found, 2n=50/FN=64, at three coastal localities of the Atlantic Forest domain, and 2n=58/FN=70 at two sites located in the Cerrado biome, Brazil Central. Two fluorescence in situ hybridization (FISH) patterns of the telomeric sequence (T₂AG₃)_n were observed: in both karyotypes the probes hybridized to the telomeres of all chromosomes and also a hybridization signal in the centromeric regions of two autosome pairs was seen in the 2n=50 karyotype. These results, together with the occurrence of other diploid numbers described in the literature, suggest that O. subflavus is a complex species, bearing fusion/fission rearrangements proper to the different biomes which it inhabits.     

An Analysis of the Amino Acid Clustering Pattern in (α/β)8 Barrel Proteins

The (/)₈ barrel proteins, in spite of having a common fold, do not show any sequence similarity. In order to understand the factors which are responsible for maintaining the common fold, the three-dimensional structures of 36 (/)₈ barrel proteins are analyzed for the presence of identical amino acid clusters or physicochemically similar clusters. The results reveal 14 identical amino acid clusters and a large number of physicochemically similar clusters. Further analysis of the similar clusters points to the conservation of secondary structures, the presence of pairs of residues occupying topologically equivalent secondary structures, and the presence of certain key residues which may play a vital role in directing and stabilizing the (/)₈ barrel fold.     

DNA reduplication during meiotic prophase in the oocytes of Carausius morosus Br. (Insecta,Cheleutoptera)

Cytological investigations combined with cytophotometric DNA determinations on Feulgen stained squash preparations of ovarioles from third and fourth instar nymphs of Carausius morosus revealed that during meiotic prophase a largely despiralized stage follows pachytene and that in this stage an extra reduplication of the nuclear DNA takes place (pachyreduplication phase). Meiotic prophase then proceeds with tetrapachytene, a pachytene-like stage with twice the amount of DNA as compared to oocyte nuclei in earlier meiotic stages, and with more than half the somatic number of elements, being probably autobivalents.Supported by Deutsche Forschungsgemeinschaft.     

Observations on the morphogenetic capacity of “residual nuclei” inAcetabularia

Summary Stalks ofAcetabularia mediterranea cells after cyst formation contain residual nuclei,e.g., secondary nuclei not used for cyst formation. Residual nuclei may lead to the formation in the stalk of direct germlings (Hämmerling 1955), cysts, and—without preceeding cyst formation—of biflagellate swarmers, identical in appearance with gametes.     

Chromosome banding in amphibia

A cytogenetic study performed on a population of the South American leptodactylid frog Eleutherodactylus maussi revealed multiple sex chromosomes of the X₁X₁X₂X₂/X₁X₂Y (=XXAA/XXA^Y) type. The diploid chromosome number is 2n=36 in all females and 2n=35 in most males. The multiple sex chromosomes originated by a centric fusion between the original Y chromosome and a large autosome. In male meiosis the X₁X₂Y (=XXA^Y) multiple sex chromosomes form a classical trivalent configuration. E. maussi is the first species discovered in the class Amphibia that is distinguished by a system of multiple sex chromosomes. Only one single male was found in the population with 2n=36 chromosomes and lacking the Y-autosomal fusion. This karyotype (XYAA) is interpreted as the ancestral condition, preceding the occurrence of the Y-autosome fusion.by H.C. Macgregor     

Analysis of DNA–Protein Contacts in a Complex between Methyltransferase SsoII and a Promoter Region of the SsoII Restriction–Modification Genes

Heterocyclic bases and phosphate groups involved in the DNA–methyltransferase SsoII (M·SsoII) interaction were identified in the regulatory DNA region localized within the promoter region of the SsoII restriction–modification genes by footprinting with the use of formic acid, hydrazine, dimethyl sulfate, and N-ethyl-N-nitrosourea as modifying agents. It has been established that the enzyme interacts with three guanines, one adenine, two thymines, and three phosphate groups of each strand of the DNA duplex. These heterocyclic bases and phosphate groups are disposed symmetrically within the 15-mer inverted repeat of the regulatory DNA region. It has been demonstrated by footprinting with dimethyl sulfate that the C7 atoms of guanines interacting with the enzyme are exposed to the DNA major groove. Two theoretical models were built describing the contacts in a complex between M·SsoII and the regulatory DNA region.     

The hemoglobins of Artemia salina. V. Genetic variation in hemoglobin 1, hemoglobin 2, and hemoglobin 3

Electrophoretic mobilities of three hemoglobins (Hb1, Hb2, and Hb3) were studied in 15 populations of brine shrimps. Genetic segregation data support the model that Hb2 contains n -polypeptides and n -polypeptides; Hb1 contains 2n -polypeptides. Hb3 contains neither - nor -polypeptides. There is no evidence of linkage of and loci with each other or with the locus (or loci) which governs Hb3 or with the nonhomologous portion of the sex chromosomes. Hemoglobins of different populations may be hybridized in vitro by incubation at high temperature. Reversible dissociation to subunits which contain only one ( or ) polypeptide occurs at 40 C (for Hb1) and at 50 C (for Hb2).Supported by Grant HD-11445 from the National Institutes of Health.     

Transposition of mobile genetic elements in interspecific hybrids of Drosophila

In situ hybridization of labeled DNA of four mobile dispersed genetic elements (mdg), isolated from D. melanogaster and C. virilis genomes, with polytene chromosomes of the larvae of several Drosophila species has been carried out. The data show that the mdg elements exhibit a high degree of species specificity. The same conclusions are derived from filter hybridization using ³²P-labeled D. melanogaster and D. virilis DNA and cloned mdg sequences immobilized on nitrocellulose filters. We attempted to induce transpositions (jumping) of mdg elements specific for D. virilis chromosomes to the chromosomes of related species (e.g. D. littoralis Meigen) originally lacking the representatives of this family of repeats. For this purpose we produced hybrid stocks with synthetic karyotoypes characterized by different combinations of D. virilis homologous chromosomes and hybrid chromosomes. In one of such stocks we did find by in situ hybridization the insertion of a D. virilis mdg element into the fifth chromosome of D. littoralis Meigen. The transposition (jumping) took place in the only region where somatic pairing between the fifth chromosomes of D. virilis and D. littoralis occurs more or less regularly in the hybrids. Since crossing-over in hybrid chromosomes of males is excluded in such synthetic stocks, gene conversion may be responsible for this transposition. The possible bearing of the phenomenon observed on the problem of hybrid dysgenesis is discussed.     

Early development of the self-fertilizing mangrove killifish <Emphasis Type="Italic">Rivulus marmoratus</Emphasis> reared in the laboratory

The mangrove killifish Rivulus marmoratus was reared at 25°±1°C and 17ppt salinity from 0 to 100 days after hatching (DAH), and its early development was described by examining growth and morphometric parameters, meristic characters (vertebral and fin-ray counts), bone-cartilage development, and pigmentation. Growth was isometric for preanal length, head length, snout length, body depth, pectoral-fin length, dorsal-fin length, anal-fin length, and caudal-peduncle depth. Negative allometric growth was observed in eye diameter and gape size. Meristic counts (mean±SD) for vertebrae (34.2±0.4) and dorsal- (8.6±0.5), anal- (11.4±0.5), and caudal-fin rays (30.2±0.8) were complete at 0 DAH (n=5), whereas pectoral-fin rays and pelvic-fin rays were complete by 30 DAH (14.5±0.4, n=5) and 60 DAH (4.2±0.8, n=5). Full ossification of meristic elements proceeded in the following sequence: vertebrae (by 30 DAH), caudal-, dorsal-, and anal-fin rays (by 60 DAH), pectoral-fin rays (between 60 DAH and 100 DAH), and pelvic-fin rays (by 100 DAH). Both morphological characters and meristic counts indicate that this species can be considered to be a juvenile after 9.8mm in standard length (20 DAH).     

Analysis of hybrids obtained by rare-mating of Saccharomyces strains

Summary Rare-mating of closely related Saccharomyces cerevisiae and S. diastaticus strains led to the formation of different hybrids. Mating-type switching and chromosome losses could be observed by means of classical genetic analysis and pulsed field gel electrophoresis of intact chromosomes. The latter was facilitated by extensive chromosome length polymorphism in both strains. When crossing the two haploid strains S. cerevisiae 41 and S. diastaticus ATCC 28339 , two different types of hybrids occurred. Both types showed complete addition of both parental genomes, one a-status and the other -status. The -status could be explained by assuming a transient premutational lesion in MAT . Usually lesions are repaired after a mating event and the -mating type is restored. When crossing a diploid S. diastaticus strain, isogenic to the one previously mentioned, with the haploid S. cerevisiae strain, three different types of hybrids could be distinguished regarding their mating-types. It was possible to prove that the haploid S. diastaticus strain ATCC 28339 is disomic and the diploid hybrid, named 41ATCC-b, is trisomic for chromosome I. This could be shown by means of electrophoretic karyotyping of the hybrid and of the four single-spore cultures from one ascus of the hybrid.     

Unequal X Chromosomes in Bradysia Hygida (Diptera:Sciaridae) Females: Karyotype Assembly and Morphometric Analysis

The mitotic chromosomes of Bradysia hygida(Diptera:Sciaridae) neuroblast cells are described together with their morphometric data. Giemsa-stained neuroblast chromosomes from female and male larvae confirm the chromosome number of this species, 2n=8 (XX) and 2n=7 (XO), respectively. The karyotype assembly reveals two metacentric autosomic pairs, the A and B chromosome; a subtelocentric, the C chromosome, the smallest one; and a sexual unequal metacentric pair, X chromosome, in female karyotype and a one sexual metacentric X chromosome in male. The implications of the unequal X chromosome pair are discussed.     

A BamHI family of highly repeated DNA sequences of Nicotiana tabacum

Summary HRS60.1, a monomer unit (184 bp) of a highly repeated nuclear DNA sequence of Nicotiana tabacum, has been cloned and sequenced. Following BamHI digestion of tobacco DNA, Southern hybridization with HRS60.1 revealed a ladder of hybridization bands corresponding to multiples of the basic monomer unit. If the tobacco DNA was digested with restriction endonucleases which have no target site in HRS60.1, the larger part of DNA homologous to HRS60.1 remained as uncleaved relic DNA. These results suggest a tandem arrangement of this DNA repeat unit. Four other clones of tobacco nuclear DNA cross-hybridized with HRS60.1, thus forming a HRS60-family. Sequencing their inserts has shown their strong mutual homology. HRS60-family comprised about 2% of the nuclear genome of N. tabacum. Computer comparisons with other tandem plant-repeated DNA sequences could not detect any other homologous sequence.     

GADD45γ, down-regulated in 65% Hepatocellular Carcinoma (HCC) from 23 Chinese patients,inhibits cell growth and induces cell cycle G2/M arrest for Hepatoma Hep-G2 cell lines

Growth-arrest and DNA-damage inducible (GADD) genes and Myeloid differentiation primary response (MyD) genes represent a family of genes that play a key role in negative control of cell growth. In the present study, following clone and location of human GADD45 (MyDL) gene, we have found that its mRNA expression level was down-regulated in 15/23 cases of clinic hepatocellular carcinoma (HCC) by comparing the northern hybridization results between the tumor tissues and adjacent normal tissues. Transient transfection of GADD45 cDNA with intact open reading frame sequence into the human hepatoma cells Hep-G2 resulted in dramatic growth suppression in colony formation assays. Furthermore, flow cytometry analysis indicated that GADD45 caused cell cycle arrest at G2/M transition when transfected into Hep-G2 cells. Therefore, the possible role of GADD45 in cell growth control was further confirmed in this paper.     

Disruption of a filamentous fungal organism (N. sitophila) using a bead mill of novel design I. General disruption characteristics

The disruption of a typical filamentous fungus, a native strain of Neurospora sitophila, was studied using a glass bead mill of novel design (the Sulzer Annu Mill 01). Cell concentration (in the range of 2.5–5 g dry weight/L) had little influence on the disruption attained. Disruption increased with increasing rotor speed (1000 –4000 r.p.m.) and number of passes (up to six passes) through the Annu Mill. Disruption was observed to follow traditional first-order kinetics for bead mills possessing predominantly plug flow characteristics. It was concluded that in general the Annu Mill would be applicable for the disruption of filamentous organisms.Nomenclature C_P aqueous-phase soluble protein concentration of disrupted sample (g/mL) - CP,MAX aqueous-phase soluble protein concentration of a completely disrupted sample (g/mL) - C_PO aqueous-phase soluble protein concentration of undisrupted sample (g/mL) - N number of passes though the bead mill (–) - R total fraction of cells disrupted (–) Greek Letters _C internal moisture volume fraction of undisrupted cells (–) - _L aqueous phase volume fraction of disrupted cell suspension (–) - _LO aqueous phase volume fraction of undisrupted cell suspension (–) - _L,MAX aqueous phase volume fraction at complete disruption (R=1) (–) - fluid density (kg/m³) - _C density of the microorganism (kg/m³) - _L density of the suspending aqueous phase (kg/m³) - suspension batch residence time in the Annu Mill 01 (min.) Abbreviations DW dry weight     

Book reviews

Consider the perturbed harmonic oscillator Ty=-y+x²y+q(x)y in L²(), where the real potential q belongs to the Hilbert space H={q, xq L²()}. The spectrum of T is an increasing sequence of simple eigenvalues _n(q)=1+2n+_n, n 0, such that _n 0 as n. Let _n(x,q) be the corresponding eigenfunctions. Define the norming constants _n(q)=lim_xlog |_n (x,q)/_n (-x,q)|. We show that for some real Hilbert space and some subspace Furthermore, the mapping :q(q)=({_n(q)}₀, {_n(q)}₀) is a real analytic isomorphism between H and is the set of all strictly increasing sequences s={s_n}₀ such that The proof is based on nonlinear functional analysis combined with sharp asymptotics of spectral data in the high energy limit for complex potentials. We use ideas from the analysis of the inverse problem for the operator -ypy, p L²(0,1), with Dirichlet boundary conditions on the unit interval. There is no literature about the spaces We obtain their basic properties, using their representation as spaces of analytic functions in the disk.     

Light-induced axial and radial shrinkage effects and changes of the refractive index in isolated bovine rod outer segments and disc vesicles

Flash-induced transients in the near-infrared scattering of bovine rod outer segments and isolated discs are investigated. Their common characteristic is the saturation at a rhodopsin bleaching of ca. 10%, which was previously described for the so-called signalP. The theory is based on the Rayleigh-Gans-approximation and on a cylindrical particle shape. This treatment is shown to be applicable in the measured angular range (in general30), in spite of the polydisperse shape of the real particles. Using the angular dependence of the relative intensity change (difference scattering curve), changes of the polarizability (refractive index) and of the particle shape can be distinguished. Model difference scattering curves are calculated for the dimensions of the rod outer segments. Static scattering measurements are used for an estimation of the average particle shape: the isolated disc samples appear to contain flat discs as well as an admixture of rod-like structures (ca. 1% of the total scattering mass); in rod outer segment preparations, a contribution of non-rodlike scattering is found which is strongly dependent on the treatment of the sample. The flash induced transients were measured using randomly oriented particles (discs and rod outer segments) and axially oriented rod outer segments. The angular dependence of the amplitude yields its difference scattering curve. On suspensions of isolated discs, which were re-loaded with the proteins extracted at low ionic strength, one single signal is observed (termedP _D, first order,=0.6–1.2 s). Using randomly oriented rod outer segments, a signal with complex millisecond kinetics (termed signalP) and a slow signal (termedP _S, first order,=5–25 s) can be distinguished kinetically. In the axially oriented rod outer segments, theP-signal splits into a fast axial (10 ms) and a slower radial component (50–100 ms). The slow signalP _S observed in ROS and the signalP _D in discs have one common physical interpretation as local changes of the polarizability, directly observed in light-scattering as a change of the refractive index. The fast signalP in ROS, however, has no detectable local component but represents a pure shrinkage effect. On the axially oriented system, this shrinkage turns out to be axial and radial with different kinetics. Only rough estimations for the relative shrinkage effects and refractive index changes can be given. One obtains for 1% rhodopsin bleaching:n/n10^–4,L/L10^–2,R/R5×10^–4. Assuming a fluid plane for the disc membrane, the planar shrinkage induced by one bleached rhodopsin is estimated from the radial shrinkage as ca. 300 å². This high value is discussed in relation to the binding of rhodopsin to the GTP-binding protein which is involved in comparable effects described by Kühn et al. (1981). According to our data, a chemical binding process in milliseconds is only indicated in the isolated disc; in the closed disc stack of the rod outer segment, only weak (fast) local interactions are consistent with the difference scattering data. A turn or lift of the GTPase would better satisfy this condition and explain the above high value for the individual shrinkage effect.Abbreviations ROS rod outer segments - RGA Rayleigh-Gans-approximation     

The karyology of the cyprinid genera <Emphasis Type="Italic">Scardinius</Emphasis> and <Emphasis Type="Italic">Rutilus</Emphasis> in southern Europe

The chromosomes of eight species of Rutilus and Scardinius, mostly endemic to the Italian and the Balkan peninsula, were analyzed by conventional and other banding techniques. Parallel analyses were conducted also on two leuciscine species, Alburnus albidus, for which we provide the first karyological analysis, and Leuciscus cephalus. All species examined displayed the same karyotype (2n=50 chromosomes, 8 metacentric+13 submetacentric+4 subtelo/acrocentric pairs) with nucleolus organizer regions (NORs) on the ends of the shorter arms of a medium-sized submetacentric pair. In contrast, interspecific variation was observed in the distribution of constitutive heterochromatin. The variation observed in this genomic material proved to be systematically and phylogenetically informative. Indeed, a peritelomeric C-band on the first telocentric pair characterizes species of Rutilus and Scardinius. In both genera heterochromatin differentiation appears to be directed to a centromere–telomere direction, particularly evident along the metacentric elements of their karyotypes.An erratum to this article can be found at