Rottboellia yellow mottle virus,a new sobemovirus affecting Rottboellia cochinchinensis (Itch grass) in Nigeria1

A hitherto undescribed virus, termed rottboellia yellow mottle virus (RoYMV), affecting Rottboellia cochinchinensis (syn. R. exaltata, itch grass) at Ibadan, Nigeria, was investigated. RoYMV virions are isometric, c. 29 nm in diameter, and sediment homogeneously at 114s. In isopycnic CsCl gradients, RoYMV virions band sharply at a buoyant density of 1.379 g cm^-3, but in Cs₂SO₄ gradients, virions band at two zones, at the densities of 1.300 g cm^-3 and 1.325 g cm^-3. Treatment with EDTA at pH 8.0 reduced the sedimentation value of RoYMV to c. 87s and rendered it susceptible to proteinase-K, SDS and NaCl. The apparent molecular weight of RoYMV coat protein was c. 27 000. Virions encapsidate a single-stranded RNA of mol. wt 1.4 × 10⁶ Da. Besides R. cochinchinensis, RoYMV was mechanically transmissible only to maize (Zea mays). No reaction occurred when RoYMV was tested against antisera to 44 isometric plant viruses (belonging to 12 groups), including several that affect Gramineae. RoYMV exhibits striking similarities with other viruses belonging to the sobemovirus group, and it is tentatively designated as a new member of the sobemovirus group.     

中国铜脚异丽金龟组及其分类问题讨论(鞘翅目:丽金龟科)(英)

新设的铜脚异丽金龟组包括中国异丽金龟属已知的大型、绿色种类,绝大多数为常见种,彼此形态十分近似。它们是:铜脚异丽金龟(新纪录)Anomala cupripes Hope new record,红脚异丽金龟(新种)A. rubripes sp. nov., 绿脚异丽金龟(新亚种)A. rubripes virescens ssp. nov., 彤脚异丽金龟(新种)A. ignipes sp. nov., 川直异丽金龟A. truncata Bates,滇直异丽金龟(新等级)A. truncata chlorochelys Arrow, stat, nov., 宽角异丽金龟A. expansa Bates,大绿异丽金龟(新种)A. virens sp. nov., 砂尾异丽金龟(新种)A. granuliformis sp. nov. 和檐角异丽金龟(新种)A. planicorna sp. nov.。其中红脚异丽金龟和绿脚异丽金龟是我国南部和台湾的重要害虫,国内外文献中长期误作铜脚异丽金龟引用至今。     

The yellow-cheeked gibbon (Hylobates gabriellae) in nam bai cat tien (southern vietnam) revisited

Data concerning the status, habitat, and vocalizations of yellow-cheeked crested gibbons (Hylobates gabriellae) were collected during a short field trip to the Nam Bai Cat Tien National Park (southern Vietnam). Nam Bai Cat Tien may be the southernmost locality where crested gibbons (i.e. theHylobates concolor group) still survive. Fewer songs were heard at Nam Bai Cat Tien National Park than at other crested gibbon sites visited by the author. At least two gibbon groups appear to have been greatly reduced in number since previous surveys in the park. There is some evidence that both the gibbon population and the gibbon habitat in Nam Bai Cat Tien are disturbed. The first case of a great call solo song in wild gibbons of theconcolor group is reported. Great calls ofH. gabriellae are described and documented with sonagrams for the first time. They differ from those previously described forH. leucogenys.     

Molecular Diversity and Evolution of bla TEM Genes Encoding β-Lactamases Resistant to Clavulanic Acid in Clinical E. coli

The molecular diversity of inhibitor-resistant TEM (IRT) enzymes was explored using a strategy which involved DNA amplification by polymerase chain reaction (PCR), analysis of restriction fragment length polymorphism (RFLP), and direct nucleotide sequencing. The study of plasmid-borne genes from 27 strains, resistant to amoxicillin and β-lactamase-inhibitor combinations, identified mutations resulting in amino acid change at positions 69, 244, 275, and 276 known to be associated with the IRT phenotype and a mutation at nucleotide position 162 in the promoter region. These mutations were found to lie on two different gene sequences, described here as ``TEM-1B like' and ``TEM-2 like' restriction linkage groups. Further analysis, of nucleotide sequences of promoter and coding regions of the β-lactamases, confirmed that a given mutation causing IRT phenotype could be associated with two different gene sequence frameworks and two different causal mutations could lie on identical gene sequence framework. These data argue in favor of convergent phenotypic evolution of IRT enzymes under the selective pressure imposed by the intensive clinical use of β-lactam–β-lactamase inhibitor combinations. Received: 18 March 1996 / Accepted: 15 July 1996     

Synonymous substitution rates in Drosophila: Mitochondrial versus nuclear genes

Synonymous substitution rates in mitochondrial and nuclear genes of Drosophila were compared. To make accurate comparisons, we considered the following: (1) relative synonymous rates, which do not require divergence time estimates, should be used; (2) methods estimating divergence should take into account base composition; (3) only very closely related species should be used to avoid effects of saturation; (4) the heterogeneity of rates should be examined. We modified the methods estimating synonymous substitution numbers to account for base composition bias. By using these methods, we found that mitochondrial genes have 1.7–3.4 times higher synonymous substitution rates than the fastest nuclear genes or 4.5–9.0 times higher rates than the average nuclear genes. The average rate of synonymous transversions was 2.7 (estimated from the melanogaster species subgroup) or 2.9 (estimated from the obscura group) times higher in mitochondrial genes than in nuclear genes. Synonymous transversions in mitochondrial genes occurred at an approximately equivalent rate to those in the fastest nuclear genes. This last result is not consistent with the hypothesis that the difference in turnover rates between mitochondrial and nuclear genomes is the major factor determining higher synonymous substitution rates in mtDNA. We conclude that the difference in synonymous substitution rates is due to a combination of two factors: a higher transitional mutation rate in mtDNA and constraints on nuclear genes due to selection for codon usage. Received: 27 November 1996 / Accepted: 8 May 1997     

COMPARATIVE MORPHOLOGY, CROSSABILITY, AND TAXONOMY WITHIN THE CALOGLOSSA CONTINUA (DELESSERIACEAE, RHODOPHYTA) COMPLEX FROM THE WESTERN PACIFIC

Systematic studies were undertaken on the Caloglossa continua ( Okamura) King et Puttock complex from Japan, Singapore, and Australia, based on morphology and reproductive compatibility. Specimens from Japan had two to six cell rows derived from a nodal axial cell, at the margin opposite the branch, whereas those from Australia possessed only a single cell row. Specimens from Singapore formed one to four cell rows per nodal axial cell and always contained at least one single cell row on any one thallus. These differences were maintained in cultured materials over a range of temperatures or salinities. Type material of C. continua had the same morphology as the Japanese specimens in this study. Carpospores discharged from the Japanese isolate germinated at 10°C, whereas those from Singapore and Australia died at this temperature. In hybridization experiments, the Japanese entity was completely nonfertile with both the Singaporean and Australian isolates. Many pseudocystocarps were produced in the crossing between the male from Australia and the female from Singapore, although the reciprocal combination did not produce any such structures. On the basis of the discontinuous morphology coupled with the complete reproductive isolation, the entities from Singapore and Australia are described here as C. monosticha sp. nov. The entities with multiple cell rows likely expanded their geographic range from tropical regions, where the majority of Caloglossa species are now distributed, to high-latitude regions, and such an expansion would be associated with acquiring low-temperature tolerance .     

The effect of season and group size on survivorship and larval growth in Plagiodera versicolora

Abstract.

• 1 The larvae of the multivoltine imported willow leaf beetle, Plagiodera versicolora (Laicharting), are found in larval aggregations during the first half of the larval stage. An experimental study was conducted to test for seasonal (brood) and group size effects on larval fitness. For each of the three broods, egg group sizes of 1, 4, 8, 16 , 24 and 32 were established in the field and monitored for the first 6 days post-hatching.
• 2 There was no effect of group size on larval weight, but there was a significant effect of group size on survival. Individuals from group size 16 had the highest survival, which coincides with the mean natural cluster size of 15.3 eggs.
• 3 There were no significant interactions between brood and group size.
• 4 The effect of larval weight on adult fitness was determined in the laboratory and the field. Larval weight was correlated with egg production in the laboratory but not in the field.

     

非酶促转氨测定蛋白质相对分子量及研究空间结构的变化

在非酶促转氨过程中测定生成甘氨酸的量,计算蛋白质的相对分子量是一种方便、节省经费和快速的方法,该方法的应用不受蛋白分子量大小的限制。非酶促转氨的另一产物２－羰化氨基酸可作为制备各种喹喔啉衍生物的原料。苯丙氨酸非酶促形成的苯丙酮酸与邻苯二胺反应生成３－苯基－２－羰基喹喔啉。该产物在３６３ｎｍ具有荧光发色性质。胰岛素及不同一级结构的短肽２－羰酰衍生物和２－喹喔啉衍生物的荧光在盐酸胍和不同ＰＨ训的变化各     

Erythrocyte Lii-Nao countertransport system Inhibition by N-ethylmaleimide probes for a conformational change of the transport system

Human erythrocytes were treated by a series of SH-reagents, including maleimides, iodo compounds, mercurials and oxidizing agents. Rates of Li efflux into Na-rich medium, Li leak and Li_i-Na_o countertransport were then determined. Of the 13 different reagents studied, only N-ethylmaleimide, iodoacetamide and iodoacetate inhibited selectively the countertransport activity. The effect of the various reagents indicates that the sensitive SH-groups of the countertransport system are not externally exposed. N-Ethylmaleimide was used to probe for changes elicited by substrate cations in Li_i-Na_o countertransport. In Na- and Li-free medium, inhibition of Li_i-Na_o countertransport by N-ethylmaleimide of 35% was reached within 2 s. In Na or Li medium, maximal inhibition was twice as great, but was attained much more slowly, within 10 min. Kinetic data and Hill plot analysis indicate the involvement of two classes of SH-groups: one expressed in the various media with and without substrate cations, and an additional one, which becomes specifically available to N-ethylmaleimide in the presence of external Na or Li. The affinity of Na to the site promoting inhibition by N-ethylmaleimide (apparent K_m  12 mM) is higher than the affinity of Na to its external countertransport site (apparent K_m  25 mM), as reported by Sarakadi, B., Alifimoff, J.K., Gunn, R.B. and Tosteson, D.C. (1978) J. Gen. Physiol. 72, 249–265). Reactivity of $\text{N-}\text{ethyl}\text{[}{}^{14}\text{C}\text{]}\text{maleimide}$ was not modified by the media tested. It is concluded that external Na and Li cause a conformational change in the protein(s) of the countertransport system in human erythrocytes.     

Phosphogluco mutase — a biochemical marker for group 4 chromosomes in the Triticinae

Summary Structural genes for the isozymes of phosphogluco mutase (PGM) (EC 2.7.5.1) have been located on chromosome arms 4A, 4BL and 4DS of hexaploid wheat. These results support the homoeologies observed among these chromosome arms and also support the notion of conservation of gene synteny groups within the Triticinae.