Histochemical analysis of oligochaete body wall

The body wall muscle fibers of Rinchelmis limosella and Enchytraeus albidus have been hystochemically characterized. The results have been compared with similar data on Lumbricus terrestris and Hirudo medicinalis. The various enzymatic activities have been correlated with the ultrastructural data and a possible functional meaning of the different muscle layers has been proposed.     

Isolation of a recombinant lambda phage carrying nusA and surrounding region of the Escherichia coli K-12 chromosome

Summary A recombinant bacteriophage lambda, argG-6, has been isolated which carries the argG gene and neighbouring loci on an EcoRI-generated 15.5 Kb DNA fragment from the Escherichia coli chromosome. The locations of the argG, nusA and pnp genes on the 15.5 Kb DNA fragment have been determined. In the case of nusA, a Tn5 insertion and sub-cloning of restriction fragments were used to locate the gene. The gene products of nusA and pnp have been identified on one- and two-dimensional polyacrylamide gels. The clockwise gene order was found to be argG-nusA-pnp.     

Isozymic gene linkage map of the tomato: Applications in genetics and breeding

Summary New linkage data are presented for the situation of five previously unlocated isozymic loci of the tomato and closely related species with homosequential chromosomes.Prx-1 lies on chromosome 1, where it is also linked withSkdh-1; Aps-2 is linked withGot-4 on chromosome 8;Tpi-2 has been allocated to chromosome 4; and a linkage has been detected betweenPgi-1 andEst-4, whose respective chromosome has not yet been determined. These and previously published data have been summarized in the form of an isozyme linkage map. Twenty-two loci have thus been mapped on nine of the twelve tomato chromosomes. We discuss some new applications of mapped isozymic genes. In certain types of segregations, isozymic genes are far more efficient than morphological markers in providing linkage information. They greatly expedite the cytogenetic investigation of species hybrids and can be utilized to facilitate backcross transfers of genes from wild to cultivated taxa.     

Molecular analysis of the extent of asymmetry in two asymmetric somatic hybrids of tomato

Summary Two somatic hybrid plants generated from a single fusion event between Lycopersicon esculentum and irradiated L. pennellii protoplasts have been analyzed at the molecular level. Over 30 loci have been analyzed using isozymes and RFLPs. All loci tested on chromosomes 2–10 were heterozygous, while those loci on chromosome 12 were homozygous L. pennellii in both somatic hybrids. In one of the somatic hybrids, 2850, loci on chromosome 1 were also homozygous L. pennellii. The other somatic hybrid, 28F5, was heterozygous at all chromosome 1 loci tested, but exhibited altered stoichiometry of parental bands as compared to the sexual hybrid. Loci on chromosome 2 from both somatic hybrids have altered stoichiometry, with L. pennellii alleles being four times more abundant than expected. Both somatic hybrids contain the L. esculentum chloroplast genome, while only L. pennellii polymorphisms have been detected in the mitochondrial genome.     

Foraging behaviour of the parasitoid Lysiphlebus testaceipes (Hymenoptera: Braconidae) in response to plant volatiles,with reference to biocontrol of aphids in peri-urban vegetable production systems

Foraging behaviour of Lysiphlebus testaceipes was studied in a Y-tube olfactometer. Naïve females responded to the Aphis gossypii/eggplant complex on which they had been reared, but did not show a preference for this aphid/plant complex over an uninfested eggplant, an eggplant that had been damaged by the aphid or an A. gossypii/okra complex. Females that had been allowed to forage on the A. gossypii/eggplant complex before being tested in the olfactometer showed a strong preference for an uninfested eggplant over an uninfested okra plant and for the A. gossypii/eggplant complex over an A. gossypii/okra complex, indicating that they had learned to associate eggplant-derived volatiles with host availability. When females that had been reared on the A. gossypii/eggplant complex were tested after foraging experience on the A. gossypii/okra complex, they did not show a preference for either complex, suggesting that they still retained a memory of the cues associated with the complex on which they had been reared. The efficiency of L. testaceipes as a biological control agent in peri-urban vegetable production, such as the Cuban organoponics system, potentially could be improved by producing and releasing females behaviourally primed to prefer specific host/plant complexes.     

Action mechanisms of probiotics on Candida spp. and candidiasis prevention: an update

Due to the high incidence of fungal infections caused by Candida species and their increasing resistance to antimicrobial treatments, alternative therapies such as probiotics have been studied. It has been show that several species of the genus Lactobacillus have anti-Candida activity, probably by direct inhibition, through competition for adhesion sites or production of secondary metabolites, and by indirect inhibition, through stimulation of the immune system of their host. However, the mechanisms of inhibition of these probiotics on Candida species have not yet been fully elucidated since this effect is related to more than one inhibition pathway. In the literature, several in vitro and in vivo studies have been developed seeking to elucidate the probiotics mechanisms of action. These studies have been focused on C. albicans inhibition assays, including analysis of antimicrobial activity, adherence capacity, biofilms formation, filamentation and interference on virulence genes, as well as assays of experimental candidiasis in invertebrate and vertebrate models. In this context, the purpose of this review was to gather different studies focused on the action mechanism of probiotic strains on Candida sp. and to discuss their impact on the candidiasis prevention.     

Absence of qualitative genes controlling interspecific pairing in rye B chromosomes

Summary The meiotic behaviour of hybrids between Secale cereale carrying B chromosomes and S. vavilovii has been studied in order to estimate the effects of B chromosomes on hybrid meiotic pairing. The possible effect of Bs on the meiotic pairing of the offspring from backcrosses with S. vavilovii has been studied also. The results obtained clearly indicate that no detectable differences existed in chromosome pairing of hybrids with or without B chromosomes. The hypothetical existence of epistatic genes on cereale genome masking the effect of Bs has been rejected after the results obtained in backcrosses. Therefore, lack of qualitative genes controlling interspecific pairing on rye B chromosomes has been concluded. A quantitative effect of B chromosomes was detected only when they were in alien cytoplasm.     

Taxonomic studies of Choanephoraceae in India

Summary A taxonomic study of the members of the family Choanephoraceae was undertaken. Almost all the species of the family have been isolated from various sources in India. Two genera, viz.,Blakeslea andChoanephora have been recognized and a key to the genera has been given. The genusBlakeslea includes only one speciesB. trispora and the genusChoanephora five species. A key to the species has also been given. A new variety ofChoanephora circinans, viz.,C. circinans var.prolifera Mehrotra andMehrotra based on the proliferating vesicular apices of the sporangiophores has been described.     

Reevaluation of the taxonomy ofVibrio,beneckea, andPhotobacterium: Abolition of the genusBeneckea

As a result of studies on the evolution of glutamine synthetase and superoxide dismutase, the genusBeneckea has been abolished and its constituent species, along withPhotobacterium fischeri andP. logei, assigned to the genusVibrio. The definitions ofVibrio andPhotobacterium have been modified accordingly.     

The first record of the rare oligolectic bumblebee Bombus gerstaeckeri Morawitz (Hymenoptera: Apidae: Bombini) lrom Ukraine

The oligolectic bumblebee Bombus gerstaeckeri Morawitz has been recorded in the Ukrainian Carpathians for the first time during field research from 2002 to 2007. Queens and workers of the species have been observed foraging on two Aconitum spp. within 540 m and 1400 m altitude. The additional forage resource of this species, that is Salvia glutinosa L., has been recorded at low height. Three competitor bumblebees, not confined only to Aconitum spp. have been observed foraging on monkshoods: B. hortorum (L.), B. pascuorum (Scopoli) and B. wurflenii Radoszkowski.     

Functional and biochemical features of alcohol dehydrogenase in four species of the obscura group of Drosophila

The biochemical features of ADH of four Drosophila species of the obscura group have been studied. The relationship between ethanol tolerance and ADH activity has been investigated. Propan-2-ol and acetone concentrations have been determined in propan-2-ol treated flies and ADH activity has been followed during 96 h of propan-2-ol treatment. Data on the ADH system confirm constructed phylogenies based on electrophoretic variation and chromosome homologies.     

Expression of Phenoloxidase System in Use of Chitooligosaccharides as Immunomodulators in Insects

Effects of chitin, chitooligosaccharides, and chitin monomer N-acetyl-D-glucosamine on activities of phenoloxidases has been studied in the honeybee Apis mellifera, Colorado beetle Leptinotansa decemliniata, and housefly Musca domestica, as well as at action of bitoxybacillin. Changes of phenoloxidase activities depending on the developmental stage and age of the insects have been studied. Expression of additional molecular forms of phenoloxidases has been shown in the housefly and Colorado beetle under effects of a bacterial preparation, chitooligosaccharides, and N-acetyl-D-glucosamine.     

Recent multiple introductions of the gall‐forming aphid Pemphigus bursarius into Japanese islands

Recently, the number of collection records of Pemphigus galls from Populus nigra has been increasing in Japan. To identify the galls on P. nigra, mitochondrial COI sequences were analyzed from galling aphid samples collected on P. nigra in Tokyo and Hokkaido. From the BLAST search and neighbor‐joining (NJ) analysis, the aphid samples were identified as Pemphigus bursarius, which has not been recorded from Japan. Two samples from Tokyo and Hokkaido showed a genetic difference of 0.30%. This result suggests that different strains of P. bursarius might have been introduced into the Japanese islands at least twice.     

Artificial sporeling and field cultivation of Gelidium in China

The supply of Gelidium resources is dependent on collection from natural habitats. As these resources are very limited, one possible means of augmenting production is by implementation of artificial cultivation as has been done with Laminaria, Porphyra and Eucheuma. Chinese phycologists have conducted research on sporeling and field cultivation of Gelidium for many years. Trials have been made using: (1) raft cultivation based on vegetative propogation of thallus fragments, (2) cultivation based on spore-collecting and land-based tank culture to provide seedstock, (3) cultivation based on regeneration from small thallus fragments to provide seedstock. Some of these results have been promising, but development remains at the experimental stage and methods of cultivation need to be improved. This paper is an updated review of the research and development on artificial sporeling production and field cultivation of Gelidium in China.     

Keystone status of plateau pikas (Ochotona curzoniae): effect of control on biodiversity of native birds

The plateau pika (Ochotona curzoniae) of the Qinghai–Xizang (Tibetan) plateau, People's Republic of China, has been considered a pest because it putatively competes with native livestock for forage and contributes to rangeland degradation. As a result the plateau pika has been poisoned across vast areas of the high alpine meadows of the plateau. The plateau pika has also been considered a keystone species for biodiversity on the plateau. As one test of the keystone species hypothesis, we investigated the effects of poisoning plateau pikas on avian species richness and abundance. We conducted standardized censuses of birds on a number of sites across the alpine grassland of Qinghai province on which pikas either had or had not been poisoned. Avian species richness and abundance were higher on non-poisoned sites, in particular for species that nest in pika burrows such as Hume's groundpecker (Pseudopodoces humilis) and six species of snowfinch (Montifringilla spp., Pyrgilauda spp.), and species that prey on pikas (upland buzzard, Buteo hemilasius; black-eared kite, Milvus lineatus). The plateau pika thus appears to be both an allogenic engineer and a keystone species. Poisoning pikas reduces biodiversity of native species on the Qinghai–Xizang plateau, therefore management decisions concerning plateau pikas should reflect caution and careful assessment.     

The role of viruses in the dynamics of phytoplankton blooms

Abstract

Viruses and virus-like particles (VLP) have been found, in most cases perchance, in about 20 marine phytoplankton species. However only in six of these have there been further investigations on this phenomenon. Different mechanisms of interaction have been hypothesized. These include continuous dynamic viral control on populations (Synechococcus spp.), at times suppressed by external environmental factors (Aureococcus anophagefferens), termination of a bloom caused by viral infection (Emiliania huxleyi and Micromonas pusilla) or by induction of lysogenic cells (Heterosigma akashiwo), and effects on the survivability of specific clones through genetic control (Aureococcus anophagefferens). These examples illustrate the complexity of virus-algae relationships and provide an indication that they may represent a key factor in the dynamics of phytoplankton blooms.     

Development of the genetic map of the yeast Saccharomycopsis lipolytica

Summary Tetrad and random spore analyses have been used to further develop the genetic map of Saccharomycopsis lipolytica. Mutations in 23 new nuclear genes have been isolated. Eight genes have been located on linkage fragment 1, 4 on fragment 2, 2 on fragment 5 and 3 on fragment 6. Linkage fragments 3 and 4 have been shown to be linked, and this fragment now contains 12 markers. A tentative map of the linkage fragments 1 and 3 is presented (Fig. 1). Markers exhibiting possible centromere linkage have been identified. Interference estimates suggest that there is little interference in S. lipolytica.     

Nucleotide sequence of Citrus limon 26S rRNA gene and secondary structure model of its RNA

The complete nucleotide sequence of Citrus limon 26S rDNA has been determined. The sequence has been aligned with large ribosomal RNA (L-rRNA) sequences of Escherichia coli, Saccharomyces cerevisiae and Oryza sativa. Nine extensive expansion segments in dicot 26S rRNA relative to E. coli 23S rRNA have been identified and compared with analogous segments of monocot, yeast, amphibian and human L-rRNAs. A secondary structure model for lemon 26S rRNA has been derived based on the refined model of E. coli 23S rRNA. It has been compared with other eukaryotic L-rRNAs models in terms of location of functionally important regions. Origin and evolution of L-rRNA expansion segments are discussed.     

Genetic examination of the type specimen of Ulva australis suggests that it was introduced to Australia

‘Ana‐aosa’, one of the most common marine green algae in Japan, was described as Ulva pertusa Kjellman in 1897 from Hakodate in northern Japan. Ulva pertusa was considered to be a temperate species, with its native distributional range restricted to northeastern Asia. Although this species has been reported from various regions outside northeastern Asia, these records have been explained as non‐indigenous populations. Recently, on the basis of genetic data and nomenclatural priority, U. pertusa was synonymized with U. australis Areschoug, a species described in 1851 from specimens collected in South Australia. Based on genetic studies, Australian populations identified as U. pertusa had been considered to have originated from Japan. However, the published genetic data on U. australis in Australia have been based only on recent collections and no historical specimens have been examined. We tested the hypothesis that native (true) U. australis is an independent species of very similar morphology to U. pertusa, but that its natural domination of shoreline habitats has been suppressed by introduced populations of U. pertusa from Asia. In the present study, we extracted DNA from the type specimen of U. australis housed in the Swedish Museum of Natural History (S) and obtained DNA sequences of the chloroplast rbcL gene and the nuclear rDNA ITS2 region. Our results show that U. australis and U. pertusa are genetically virtually identical, confirming that U. pertusa is a synonym of U. australis. This suggests that the introduction of U. australis to Australia occurred by the middle of the 19th century, when the type was collected and before there was a direct shipping route between Japan and Australia. We speculate that the introduction of U. australis to Australia occurred as a secondary introduction from non‐indigenous populations in northeastern Asia, but not directly from Japan.     

A note on the potential applicability of malachite green oxalate in combating fish-mycoses

In the present investigations the potential fungicidal ability of malachite green oxalate has been tested in vitro on four fish-pathogenic isolates of Saprolegniaceous fungi viz.,Saprolegnia ferax (Gruith) Thuret,Achlya flagellata Coker,Aphanomyces laevis De Bary andIsoachlya anisospora var.indica Saxena and Bhargava and the lowest concentration having fungicidal ability has been found to be 0.5 ppm. Tolerance tests have also been conducted usingPuntius sophore, Colisa lalia, Anabas testudineus andCatla catla as test fishes. Also the applicability of the lowest fungicidal concentration of this chemical (i.e. 0.5 ppm) in sustained culturing of the adult individuals ofCatla catla, a major food fish, against the mycotic infection, has been tested.