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.     

The cytology of phytophthora infestans

Summary Phytophthora infestans has three kinds of somatic nuclei: an oval shaped nucleus (approx. 3.1×2.7 ) which stains diffusely except for a crescent shaped Feulgen positive cap which stains intensely; a granular nucleus whose contents are organized into a fairly constant number of stained bodies, and, a deeply staining condensed nucleus. The capped nucleus is thought to be metabolic or resting and the granular nucleus is thought to be dividing as it is most commonly found in hyphal tips. Attenuated forms of all three kinds of nuclei are found.Nuclear division is mitotic and intranuclear. Eight—ten chromosomes are seen at metaphase.Sporangia have a mean of 6.3 nuclei which is constant for age and strain of culture. Sporangia become multinucleate as a result of nuclear migration and not by division in the developing sporangium. Zoospores are usually uninucleate.The nuclear cap is persistent throughout nuclear division when it also divides. It is associated with flagella production and nuclear migration and has some of the properties of a blepharoplast.     

Characterization of chromosomes with hybrid genes for Hb Lepore-Washington,Hb Lepore-Baltimore,Hb P-Nilotic,and Hb Kenya

Summary This study concerns the characterization of chromosomes with hybrid genes for Hb Lepore-Washington (44 chromosomes), for Hb Lepore-Baltimore (5 chromosomes), for Hb P-Nilotic (8 chromosomes), and for Hb Kenya (7 chromosomes) by determining a relatively large number of restriction enzyme polymorphism. Two, and possibly three, different Hb Lepore-Washington chromosomes were identified by specific haplotypes, while the haplotype of the Hb Lepore-Baltimore chromosome had its own characteristic pattern. A likely conclusion is that the crossovers leading to the formation of these chromosomes have occurred as independent events within the populations. Chromosomes with the -Lepore-Washington hybrid gene maintained specific characteristies (such as increased Hb F levels in heterozygotes, and high or low ^G values in this Hb F) which have been observed in normal individuals with chromosomes having comparable haplotypes. Only one haplotype was observed for each of the chromosomes carrying either the -P-Nilotic hybrid gene or the ^A hybrid gene of Hb Kenya.     

Generalized recombination in tandem duplications of bacteriophage lambda

Summary Recombination between the tandem duplicated segments of b221a106-15 yields unduplicated (single-copy) b221 phage. The apparent frequency of intramolecular events among these recombinations was determined for both cellular (Rec) and bacteriophage (Red) generalized recombination systems. The progeny from single-cycle growth experiments with genetically marked duplication phages were treated with EDTA to inactivate all but the singlecopy phages produced by recombination. Analysis of the genotypes of the EDTA-resistant phages suggested that intramolecular events were about 1 to 5 times as frequent as intermolecular ones. While the results suggest that intramolecular events are not intrinsically forbidden, the quantitative values for the ratio depend on the assumption that intracellular phage chromosomes are completely mixed.     

Purification and properties of gammagamma-enolase from pig brain

Isoelectric focusing revealed three enolase isoforms in pig brain, which were designated as - (pI = 6.5), - (pI = 5.6), and -enolase (pI = 5.2). The pI of purified -enolase was also 5.2. The -enolase isoform of enolase was purified from pig brain by a purification protocol involving heating to 55°C for 3 min, acetone precipitation, ammonium sulfate precipitation (40%–80%), DEAE Sephadex ion-exchange chromatography (pH 6.2), and Sephadex G200 gel filtration. The final specific activity was 82 units/mg protein. As with other vertebrate enolases, -enolase from pig proved to be a dimer with a native mass of 85 kDa and a subunit mass of 45 kDa. The pH optimum for the reaction in the glycolytic direction is 7.2. The K _m values for 2-PGA, PEP, and Mg²⁺ were determined to be 0.05, 0.25, and 0.50 mM, respectively, similar to K _m values of other vertebrate enolases. The amino acid composition of pig -enolase, as determined by amino acid analysis, shows strong similarity to the compositions of -enolases from rat, human, and mouse, as determined from their amino acid sequences. Despite the differences seen with some residues, and considering the ways that the compositions were obtained, it is assumed that pig -enolase is more similar than the composition data would indicate. Moreover, it is likely that the sequences of pig -enolase and the other -enolases are almost identical. Li⁺ proved to be a noncompetitive inhibitor with either 2-PGA or Mg²⁺ as the variable substrate. This enolase crystallized in the monoclinic space group P2, or P2₁. An R _symm <5% was obtained for data between 50 and 3.65 Å, but was a disappointing 30% for data between 3.65 and 3.10 Å, indicating crystal disorder.     

The Use of the [13C]/[12C] Ratio for the Assay of the Microbial Oxidation of Hydrocarbons

The study deals with a comparative analysis of the relative abundances of the carbon isotopes ¹²C and ¹³C in the metabolites and biomass of the Burkholderia sp. BS3702 and Pseudomonas putida BS202-p strains capable of utilizing aliphatic (n-hexadecane) and aromatic (naphthalene) hydrocarbons as sources of carbon and energy. The isotope compositions of the carbon dioxide, biomass, and exometabolites produced during the growth of Burkholderia sp. BS3702 on n-hexadecane (¹³C = –44.6 ± 0.2) were characterized by the values of ¹³C_{CO 2} = –50.2 ± 0.4, ¹³C_biom = –46.6 ± 0.4, and ¹³C_exo = –41.5 ± 0.4, respectively. The isotope compositions of the carbon dioxide, biomass, and exometabolites produced during the growth of the same bacterial strain on naphthalene (¹³C = –21 ± 0.4) were characterized by the isotope effects ¹³C_{CO 2} = –24.1 ± 0.4, ¹³C_biom = –19.2 ± 0.4, and ¹³C_exo = –19.1 ± 0.4, respectively. The possibility of using the isotope composition of metabolic carbon dioxide for the rapid monitoring of the microbial degradation of petroleum hydrocarbons in the environment is discussed.     

The major cystic fibrosis mutation in a British population

Summary We have studied 72 families with at least one child with cystic fibrosis (CF); they were referred because they had requested pre-natal diagnosis in a future pregnancy. The F508 mutation was found in 108/140 CF chromosomes (77%). In 41/72 families (57%), both parents carried a deleted chromosome and the child was doubly deleted. In only 4 families, 2 of them being consanguineous, did neither parent carry a deleted chromosome. Meconium ileus was associated with children who were F508/F508, F508/non-deleted and non-deleted/ non-deleted.This paper should have been published in Human Genetics, Vol.85, No.4, 1990, together with the other European data on Population analysis of the major mutation in cystic fibrosis. Its publication was delayed for technical reasons     

Simultaneous removal of chemical oxygen demand and nitrate in aerobic treatment of sewage wastewater using an immobilized photosynthetic bacterium of porous ceramic plates

A denitrifying photosynthetic bacterium (PSB), Rhodobacter sphaeroides S was immobilized on a porous ceramic plate (10×10×0.5cm) using a small amount of agar. In the bioreactor (3.5 l liquid) using this plate, repeated batch treatments of sewage wastewater (acetic acid as a carbon source) were carried out under aerobic conditions (DO 5mg/l) for two weeks. The simultaneous and effective removal of chemical oxygen demand (COD), ammonium, and nitrate was observed. In continuous treatment at a relatively high dilution rate of 0.20 h^–1 (retention time, five hours), the same simultaneous treatments were observed for about one month.     

Characterization of the MHC class II region in cattle. The number of DQ genes varies between haplotypes

The organization of the major histocompatibility complex (MHC) class II region in cattle was investigated by Southern blot analysis using human probes corresponding to DO, DP, DQ, and DR genes. Exon-specific probes were also employed to facilitate the assessment of the number of different bovine class II genes. The results indicated the presence of single DO and DR genes, at least three DR genes, while the number of DQ genes was found to vary between MHC haplotypes. Four DQ haplotypes, DQ ^{1 1} to DQ ^{2 4}, possessed a single DQ and a single DQ gene whereas both these genes were duplicated in eight other haplotypes, DQ ^{3 5} to DQ ^{9 12}. No firm evidence for the presence of bovine DP genes was obtained. The same human probes were also used to investigate the genetic polymorphism of bovine class II genes. DQ DQ , DR DR , and DO restriction fragment length polymorphisms (RFLPs) were resolved and in particular the DQ restriction fragment patterns were highly polymorphic. Comparison of the present result with the current knowledge of the class II region in other mammalian species suggested that the DO, DP, DQ, DR, and DZ subdivision of the class II region was established already in the ancestor of mammals. The DP genes appear to be the least conserved class II genes among mammalian species and may have been lost in cattle. The degree of polymorphism of different class II genes, as revealed by RFLP analyses, shows striking similarities between species.     

Satellited chromosomes,systematics and phylogeny inTaraxacum (Asteraceae)

A survey is made of the occurrence, nature and frequency of satellited chromosomes in the agamospermous genusTaraxacum. Species belonging to the 10 sections thought to be most primitive in the genus lack satellited chromosomes. In most other sections, a characteristic satellited chromosome is seen with a large euchromatic region distal to the presumed nucleolar oraniser region (NOR). In sections of a precursor type, there is always one chromosome of this Taraxacum type per haploid genome. In sections thought to be of an advanced type the number of such satellited chromosomes is very unstable, sometimes even within the same tissue. In sectionHamata, two such satellited chromosomes are invariably found in triploids. This finding strongly supports the integrity of this section, suggests that the species of the section are monophyletic, and have evolved from a single ancestor subsequent to the occurrence of obligate agamospermy. In three sections of the genus, satellited chromosomes of the conventional type with a very small distal euchromatic region distal to the NOR are reported for the first time in the genus.     

Evolution of a protein superfamily: Relationships between vertebrate lens crystallins and microorganism dormancy proteins

Summary A search of sequence databases shows that spherulin 3a, an encystment-specific protein ofPhysarum polycephalum, is probably structurally related to the - and -crystallins, vertebrate ocular lens proteins, and to Protein S, a sporulation-specific protein ofMyxococcus xanthus. The - and -crystallins have two similar domains thought to have arisen by two successive gene duplication and fusion events. Molecular modeling confirms that spherulin 3a has all the characteristics required to adopt the tertiary structure of a single -crystallin domain. The structure of spherulin 3a thus illustrates an earlier stage in the evolution of this protein superfamily. The relationship of - and -crystallins to spherulin 3a and Protein S suggests that the lens proteins were derived from an ancestor with a role in stressresponse, perhaps a response to osmotic stress.     

Properties of β-glucosidase purified from Aspergillus niger mutants USDB 0827 and USDB 0828

Summary Two extracellular -glucosidases (EC 3.2.1.21) were isolated from Aspergillus niger USDB 0827 and A. niger USDB 0828, and their physical and kinetic properties studied. Both enzymes were very similar in terms of molecular size (230000 Da), pH optimum (pH 4.6), temperature optimum (65° C), stability at high temperatures and substrate preferences. They were capable of hydrolysing -linked disaccharides, phenyl -d-glucoside, p-nitrophenyl -d-glucoside (PNPG), o-nitrophenyl -d-glucoside, salicin and methyl -d-glucoside but lacked activity towards -linked disaccharides, a range of p-nitrophenyl monoglycosides and p-nitrophenyl diglycosides. Both -glucosidases were better at hydrolysing cellobiose than cellotriose, cellotetraose or cellopentaose. For both enzymes, glucose showed competitive inhibition with PNPG as substrate but had no effect with cellobiose. However, the two -glucosidases differed in inhibition by glucono-1,5-lactone and affinity for cellobiose. -Glucosidase from A. niger USDB 0827 also gave lower specific activity, and was more susceptible to metal ions (Ag⁺, Fe²⁺ and Fe³⁺) inhibition than that of A. niger USDB 0828. Correspondence to: Y. K. Hoh     

Electrophoretic analysis of the high-molecular-weight glutenin subunits of Triticum monococcum,T. urartu,and the A genome of bread wheat (T. aestivum)

Summary The high molecular weight (HMW) subunit composition of glutenin was analysed by sodium dodecyl sulphate, polyacrylamide gel electrophoresis (SDS-PAGE) in the A genome of 497 diploid wheats and in 851 landraces of bread wheat. The material comprised 209 accessions of wild Triticum monococcum ssp. boeoticum from Greece, Turkey, Lebanon, Armenia, Iraq, and Iran; 132 accessions of the primitive domesticate T. monococcum ssp. monococcum from many different germplasm collections; one accession of free-threshing T. monococcum ssp. sinskajae; 155 accessions of wild T. urartu from Lebanon, Turkey, Armenia, Iraq, and Iran; and landraces of T. aestivum, mainly from the Mediterranean area and countries bordering on the Himalayan Mountains. Four novel HMW glutenin sub-units were discovered in the landraces of bread wheat, and the alleles that control them were designated Glu-Ald through Glu-Alg, respectively. The HMW subunits of T. monococcum ssp. boeoticum have a major, x subunit of slow mobility and several, less prominent, y subunits of greater mobility, all of which fall within the mobility range of HMW subunits reported for bread wheat. In T. monococcum ssp. monococcum the range of the banding patterns for HMW subunits was similar to that of ssp. boeoticum. However, two accessions, while containing y subunits were null for x subunits. The single accession of Triticum monococcum ssp. sinskajae had a banding pattern similar to that of most ssp. boeoticum and ssp. monococcum accessions. The HMW subunit banding patterns of T. urartu accessions were distinct from those of T. monococcum. All of them contained one major x and most contained one major y subunit. In the other accessions a y subunit was not expressed. The active genes for y subunits, if transferred to bread wheat, may be useful in improving bread-making quality.     

Retention of lead within the digestive vacuole inTetrahymena

Summary The ciliateTetrahymena pyriformis was exposed to lead acetate. Cell proliferation in the presence of 0.1% lead salt (with or without EDTA) equaled, after a variable lag period, that of the control cells. The lead (550 ppm) forms a fluffy precipitate with the organic growth medium; this was in part prevented by addition of EDTA. The cells primarily ingested the fluffy precipitate whereby they became exposed to large amounts of lead. Within the digestive vacuole, the fluffy precipitate became converted into refractile structures (3 m in diameter) which were egested and accumulated at the bottom of the culture flask. The lead content of these defecation balls was higher than that of the fluffy precipitate. In addition to the lead-containing vacuoles, the cells contained small, refractile granules. The apparent, high tolerance ofTetrahymena towards lead is believed to be due in part to the low ionic concentration of lead under the present conditions and in part to a detoxication mechanism consisting of retention of lead within the digestive vacuoles and perhaps of accumulation of lead within the small, refractile granules.     

Structure-function relationships of β- D-glucan endo- and exohydrolases from higher plants

(13),(14)--d-Glucans represent an important component of cell walls in the Poaceae family of higher plants. A number of glycoside endo- and exohydrolases is required for the depolymerization of (13),(14)--d-glucans in germinated grain or for the partial hydrolysis of the polysaccharide in elongating vegetative tissues. The enzymes include (13),(14)--d-glucan endohydrolases (EC 3.2.1.73), which are classified as family 17 glycoside hydrolases, (14)--d-glucan glucohydrolases (family 1) and -d-glucan exohydrolases (family 3). Kinetic analyses of hydrolytic reactions enable the definition of action patterns, the thermodynamics of substrate binding, and the construction of subsite maps. Mechanism-based inhibitors and substrate analogues have been used to study the spatial orientation of the substrate in the active sites of the enzymes, at the atomic level. The inhibitors and substrate analogues also allow us to define the catalytic mechanisms of the enzymes and to identify catalytic amino acid residues. Three-dimensional structures of (13),(14)--d-glucan endohydrolases, (14)--d-glucan glucohydrolases and -d-glucan exohydrolases are available or can be reliably modelled from the crystal structures of related enzymes. Substrate analogues have been diffused into crystals for solving of the three-dimensional structures of enzyme-substrate complexes. This information provides valuable insights into potential biological roles of the enzymes in the degradation of the barley (13),(14)--d-glucans during endosperm mobilization and in cell elongation.     

Inhibitory Effects of Bombusae concretio Salicea on Neuronal Secretion of Alzheimer's β-Amyloid Peptides, a Neurodegenerative Peptide

Alzheimer's disease (AD) is characterized by the age-related deposition of -amyloid (A) 40/42 peptide aggregates in vulnerable brain regions. Multiple levels of evidence implicate a central role for A in the pathophysiology of AD. A is generated by the regulated cleavage of a = 700 amino acid A precursor protein (APP). Full-length APP can undergo proteolytic cleavage either within the A domain to generate secreted sAPP or at the N-terminal and C-terminal domain(s) of A to generate amyloidogenic A peptides. Several epidemiological studies have reported that estrogen replacement therapy protects against the development of AD in postmenopausal women. The aim of this study was to elucidate the antioxidant neuroprotective mechanism of Bombusae concretio Salicea (BC). BC was effective protectants against oxidative glutamate toxicity in the murine neuroblastoma cells (N2a) and human neuroblastoma cells (SK-N-MC). BC exhibited similar protective properties against oxidative glutamate toxicity and H₂O₂ toxicity. BC exhibited an antioxidant activity at approximately 20 g/ml. BC of 5 g/ml was ineffective in preventing the oxidative modification of LDL. The half-maximal effective concentration for BC was 16 g/ml. These results suggested that BC supplementation in elderly men may be protective in the treatment of Alzheimer's disease (AD). We report here that treatment with BC increases the secretion of the nonamyloidogenic APP fragment, sAPP and decreases the secretion of A peptides from N2a cells and rat primary cerebrocortical neurons. These results raise the possibility that BC supplementation in elderly men may be protective in the treatment of AD.     

L cells expressing DQ molecules of the DR3 and DR4 haplotypes: reactivity patterns with mAbs

cDNAs coding for the HLA class II DR and DQ and chains of the diabetogenic haplotypes DR3 and DR4 were introduced into a mammalian expression vector and transfected into L-cell mouse fibroblasts to produce cells expressing individual human class II molecules. Stable L transfectants were generated expressing each of the DR or DQ isotypes of the cis-encoded and chains of the DR3 or DR4 haplotypes, as well as the trans-encoded and chains of the DQ molecules of the two haplotypes. However, isotype mismatched combinations (DR/DQ or DQ/DR) did not result in any stable transfectants. The stable DQ L-cell transfectants obtained, along with homozygous B-cell lines expressing the DQ2 and DQ8 specificities, were tested against a large panel of twentyone anti-HLA class II monoclonal antibodies (mAbs). Their unusual reactivity patterns are described including the failure of most pan-DQ mAbs to react with all DQ expressing L-cell transfectants. Interestingly, some mAbs react with certain heterodimers expressed on B-LCL but fail to recognize the same heterodimers expressed on the transfectants. This is suggestive of minor structural modifications that class II molecules undergo depending on the cells they are expressed on.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession number U07848. The name DQB1 ^* 0202 was officially assigned by the WHO Nomenclature Committee in April 1994. This follows the agreed policy that, subject to the conditions stated in the most recent Nomenclature Report (Bodmer et al. 1992), names will be assigned to new sequences as they are identified. Lists of such new names will be published in the following WHO Nomenclature Report     

The filtration apparatus of Cladocera: Filter mesh-sizes and their implications on food selectivity

Summary The filtering apparatus of eleven Cladoceran species was studied. The distances between the setulae, which act as filters, were measured. Among adult individuals, they vary from 0.2 m in Diaphanosoma brachyurum to 4.7 m in Sida crystallina. Species can be grouped according to the mesh-sizes, as fine mesh filter-feeders: Diaphanosoma brachyurum, Ceriodaphnia quadrangula, Chydorus sphaericus, Daphnia cucullata and Daphnia magna; medium mesh filter-feeders: Daphnia galeata, D. hyalina. D. pulicaria, Bosmina coregoni, and coarse mesh filter-feeders: Holopedium gibberum and Sida crystallina. In Daphnia hyalina, the distances between setulae increase from 0.3–0.4 m in small juveniles, to 0.8–2.0 m in adults. In Daphnia magna, the mesh-size of the filter does not increase significantly with growth. There is good evidence that the relative abundance of the filter-feeding types varies with the trophic state of the lake. In oligotrophic lakes the coarse mesh filter-feeders usually dominate throughout the year. The seasonal succession of zooplankton species in eutrophic lakes can be interpreted as a succession of feeding types; during winter coarse mesh filter-feeders dominate, while fine mesh filter-feeders are most abundant during summer phytoplankton blooms. Our results support the hypothesis that the species composition of filter-feeding zooplankton is strongly influenced by the amount of suspended bacteria which are available as food only for filter-feeding species with fine meshes.     

Relative positions of homologous chromosomes or groups in male and female metaphase figures

Summary This study investigates statistically, with computer assistance, the square distances between chromosome centromeres in homologous pairs or groups after circularizing transformation. By the method described here, it is possible to eleminate all subjective measurments and just use the coordinates x _i and y _i of the centromeres. The values obtained for homologous chromosomes are shown to be specific but not always small. Low square distance values occur in greater number for the chromosomes that are most frequently involved in aneuploïdies. This is true for acrocentric chromosomes which, moreover, tend to lie close together significantly more often in female than in male mitoses; it is also true for group 17–18 especially in males, and of XX in female mitoses. Furthermore, we find significantly low square distances in chromosome pair 1.     

The frequency of the γ chain variant AγT in different populations,and its use in evaluating γ gene expression in association with thalassemia

Summary The occurrence of the ^AT chain (i.e. ^A75 Ile Thr) in different populations was evaluated through a study of 4250 cord blood samples and blood samples from more than 350 SS¹ patients. High frequencies were observed in Italy, Yugoslavia, Turkey, Holland, but also in Japan, Vietnam, and India. The chain is (nearly) absent in the Black population of Ghana and Kenya, and low frequencies were observed in China and Australian aborigines. Only a few adult SS patients (18 out of 357) were ^AT heterozygotes. The chromosomes with the ^AT globin gene were mapped through an evaluation of the presence of 10 different restriction sites. The ^AT chromosomes from different populations were closely related and had the same subhaplotypes of [--++-+] (Hinc II 5 to ; Xmn I 5 to ^G; Hind III in ^G and ^A; Hinc II in and 3 to ), quite different from the subhaplotypes seen for ^AT negative chromosomes.² This suggests a common ancestor which may have originated in Southern Europe. An evaluation of the chain production by both chromosomes in SS patients and -thalassemia heterozygotes was possible for subjects with an ^AT heterozygosity. It was concluded that in -thalassemia trait, the chain synthesis is directed for about two-thirds by the thalassemic chromosome and for about onethird by the normal chromosome; the contribution by the normal chromosome decreases with a decrease in total chain production.This is contribution #0890 of the Department of Cell and Molecular Biology, Medical College of Georgia, Augusta, GA 30912, USA