Water relations of the root hemiparasite Olax phyllanthi (Labill) R.Br. (Olacaceae) and its multiple hosts

Summary Water relations of the root hemiparasite Olax phyllanthi were compared with those of its major species of hosts in natural habitat in coastal heath near Denmark, SW Australia. Leaf water potentials of Olax during winter were 0.4 to 1.4 MPa lower (more negative) than those of all (29) non parasitic host species examined. During the dry summer months (January to March), shallow-rooted hosts developed water potentials up to 3 MPa lower than those of Olax, and were accordingly rated as no longer accessible as a source of water to the hemiparasite. By contrast, deep-rooted hosts, with access to the water table, showed water potentials less negative than Olax, and haustorial contacts retained with these apparently enabled continued extraction of water and nutrients throughout the summer. Three other species of root hemiparasites parasitized by Olax, but not themselves parasitizing Olax, showed leaf water potentials throughout the year very close to, and mostly slightly more negative than those of Olax. Nocturnal measurements of leaf water potential in winter (July and August) in soil at field capacity (water potential –0.006 MPa) showed maintenance of a 0.5–0.8 MPa potential difference between Olax and a range of common host species. By dawn most hosts had equilibrated with the water potential of the soil, whereas both exposed and bagged Olax plants recorded potentials of –0.8 MPa. Daytime rates of transpiration and photosynthesis of Olax were less than those of a range of common hosts, but water use efficiencies were not consistently different between hemiparasite and hosts. This was reflected in almost identical mean values for carbon isotope ratio (¹³C/¹²C) between Olax (mean value –27.0) and thirteen frequently exploited hosts ( value –27.1). The results are discussed in relation to published information on other angiosperm hemiparasites.     

The effect of host size on the sex ratio of Syngaster lepidus, a parasitoid of Eucalyptus longhorned borers (Phoracantha spp.)

The solitary larval ectoparasitoid, Syngaster lepidus Brullé, parasitizes the cryptic larvae of two wood-boring beetles, Phoracantha recurva Newman and Phoracantha semipunctata F. The objective of this study was to determine how the female parasitoids allocated the sex of progeny when presented with larval hosts of uniform size classes. Host size was directly correlated with age of the Phoracantha larval hosts. Groups of Phoracantha larvae of a single age class (2-, 3-, 4-, or 5-week-old) were exposed to parasitoids, and sex ratios of the resulting parasitoid progeny from each host age class were determined. A significant relationship was observed among the sizes of P. recurva and P. semipunctata hosts and the sex ratio of emerging parasitoids. Parasitized 2-week-old beetle larvae of both Phoracantha spp. produced only male S. lepidus progeny, whereas older larval hosts produced increasing proportions of female parasitoids (up to 80% females from 5-week-old hosts). Two-week-old Phoracantha larvae of both species produced fewer parasitoids than host larvae 3–5-week-old. The size of parasitoid progeny consistently increased with host larval age (size), and female parasitoids were larger than males across all host size classes. Male S. lepidus developed in approximately 25 days from 2-week-old hosts, and 19–21 days in 3–5-week-old hosts. Female S. lepidus developed in 22–25 days, with developmental time increasing with host size.     

Postemergence learning in the insect parasitoid,Cotesia congregata (Say) (Hymenoptera: Braconidae)

Exposing newly emerged females of Cotesia congregata(Say) to wild cherry, an inherently unattractive plant, and their host larvae at 0–4 h after adult emergence induced a positive searching response to wild cherry and an inhibited response to cabbage, an attractive plant. Inherent responses were not affected when females were exposed to their hosts at 0–12 h and to cherry at 8–12 h after emergence. The induced response to cherry was constant until its disappearance at 6–7 days;inhibition of the response to cabbage was released at 4–5 days after emergence. Postemergence exposure to cherry and parasitoid cocoons induced similar but weaker searching responses. Induced searching responses exhibit features of associative learning and receptor modification. In addition to its presumed role in foraging, postemergence experience with plants may encourage assortative mating of C. congregatawithin suitable host habitats and, thus, facilitate local adaptations to specific plants.     

Characteristics of natural strains of naphthalene-utilizing bacteria of the genus <Emphasis Type="Italic">Pseudomonas</Emphasis>

Sixty-three strains of bacteria capable of utilizing naphthalene as the sole source of carbon and energy were isolated from 137 samples of soil taken in different sites in Belarus. All isolated bacteria contained extrachromosomal genetic elements of 45 to 150 kb in length. It was found that bacteria of 31 strains contained the IncP-9 incompatibility group plasmids, bacteria of one strain carried a plasmid containing replicons IncP-9 and IncP-7, and bacteria of 31 strains contained unidentified plasmids. Primary identification showed that the hosts of plasmids of naphthalene biodegradation are fluorescent bacteria of the genus Pseudomonas (P. putida and P. aeruginosa; a total of 47 strains) and unidentified nonfluorescent microorganisms (a total of 16 strains). In addition to the ability to utilize naphthalene, some strains exhibited the ability to stimulate the growth and development of the root system of Secale cereale.Translated from Izvestiya Akademii Nauk, Seriya Biologicheskaya, No. 2, 2005, pp. 162–167.Original Russian Text Copyright © 2005 by Levchuk, Vasilenko, Bulyga, Titok, Thomas.     

Subjective Estimation of the Trajectory Length of Fused Auditory Image Movement

The perceived trajectory length of the movement of a fused auditory image (FAI) against the background of interaural intensity differences was estimated in eight subjects upon dichotic stimulation through headphones. FAI movement was created by gradually changing the interaural delay (ΔT) between clicks in binaurally presented series of clicks from 0 to ±630 μs. When the FAI moved from the left to the right, an increase in interaural intensity difference (ΔI) from 0 to +13 dB (in the right channel of stimulation) significantly shortened the FAI trajectory because of a greater lateralization of the start point of FAI movement as compared to its end point. In the case of an oppositely directed movement (from the right to the left), the movement trajectory significantly decreased when ΔI increased from 0 to −13 dB (i.e., in the left stimulation channel), which was also explained by the greater lateralization of the start point of FAI movement as compared to its end point.__________Translated from Fiziologiya Cheloveka, Vol. 31, No. 3, 2005, pp. 32–38.Original Russian Text Copyright © 2005 by Varyagina.     

First Isolation of the Yeast <Emphasis Type="Italic">Saccharomyces paradoxus</Emphasis> in Western Siberia

Two ascomycetous yeast strains have been isolated near Novosibirsk from oak exudate. The strains have been identified as Saccharomyces paradoxus Bachinskaya based on the results of biochemical tests. The conspecificity of the isolates with S. paradoxus was confirmed by electrophoretic karyotyping and restriction analysis of the ITS region of its rDNA. This first isolation of S. paradoxus in Siberia provides evidence for the continuity of its natural habitats.__________Translated from Mikrobiologiya, Vol. 74, No. 4, 2005, pp. 533–536.Original Russian Text Copyright © 2005 by Yurkov.     

Genetic and phenotypic variation in diet breadth in a generalist herbivore

Summary The genetic and plastic components of polyphagy were investigated in a population ofLymantria dispar, the gypsy moth. A simple genetic experiment assessed the expression of (1) genetic variability in life history traits within each of four environments, (2) genetic variability in diet breadth, expressed as a change in the ranks of family performance across hosts, and (3) homeostasis (equivalent performance by a family across hosts) versus phenotypic plasticity (variable performance by a family across hosts). Sibs from each of 14 families, randomly selected from a single population, were reared on four diets: two natural hosts — chestnut and red oak, and two synthetic hosts — a standard laboratory diet and a low-protein version of this diet. Average population performance, measured in terms of development time and pupal weight, was better on standard laboratory diet than on low-protein diet, and was equal on chestnut and red oak for pupal weight, but better on chestnut oak for development time. Average population performance provided no information about the genetic component of host use ability. The gypsy moth expressed genetic variation in development time within each host environment and in pupal weight within natural host environments. Phenotypic plasticity was expressed by a significant number of families in development time and pupal weight across synthetic hosts and, to a lesser extent, across natural hosts. It was only across natural hosts that genetic variation in diet breadth was expressed, and this was confined to females. Genetic variability in diet breadth may be maintained in this species as a consequence of the unpredictability of its food sources.     

Lack of expression of RP4-specified β-lactamase in Azospirillum brasilense

Plasmid RP4, which normally confers resistance to ampicillin (Ap^r), tetracycline (Tc^r), and kanamycin (Km^r) to its hosts, failed to express enhanced Ap^r when transferred from Escherichia coli to Azospirillum brasilense which has its own intrinsic β-lactamase. Even in a β-lactamase-deficient mutant, A. brasilense RG-D16, no increase in β-lactamase or significant Ap^r appeared following transfer of RP4. However, A. brasilense RG (RP4) and A. brasilense RG-D16 (RP4) did exhibit Tc^r Km^r. When RP4 was transferred back from A. brasilense to E. coli all three drug resistances and β-lactamase activity were fully expressed.     

Diatom symbionts in larger foraminifera from Caribbean hosts

Larger foraminifera, as a group, are the hosts for many different types of algae. The majority of modern families host small (< 10 μm) pennate endosymbiotic diatoms. In these, the host/symbiont relationship is not finical. Studies from hosts harvested from Indo-Pacific habitats have shown some symbiont species are found with greater frequency than others, but any one of twenty different diatom species may be found in the same host. This study examined the endosymbionts from two diatom-bearing hosts from the Caribbean, Amphistigina gibbosa and Heterostegina antillarum. A high number of hosts harbored more than one symbiont species. A new variety of Nitzschia frustulum was involved in many (33%) of the symbioses. Many of the isolates of this taxon, if it is to be considered only one, are extremely aberrant forms for the genus. Another common (18%) isolate was an unidentified species of Navicula. A highly variable Amphora sp. was also isolated. These taxa will require more detailed examination in the future. Many of the isolates from the Caribbean hosts also were known as endosymbionts from previous studies: Nitzschia laevis N. frustulum var. symbiotica N. valdestriata, Amphora tenerrima, Navicula muscatini, Cocconeis andersoni and Fragillaria shiloi. A number of endosymbiotic species, common in Indo-Pacific hosts, were not found in the Caribbean hosts studied. The results of the present study are in consonance with those of previous studies.     

Synthesis and Properties of the <Emphasis Type="Italic">retro</Emphasis>-Analogue of Myelopeptide MP-2

The bone marrow myelopeptide MP-2 (Leu-Val-Val-Tyr-Pro-Trp), exhibiting antitumor activity, and its retro-analogue (Trp-Pro-Tyr-Val-Val-Leu) were synthesized, and their properties were studied. The in vitro and in vivo activities of retro-MP-2 were comparable with those of MP-2. Both peptides equally restored the functional activity of T-lymphocytes inhibited by toxins released by HL-60 cells and inhibited by 70–82% the growth of various types of transplantable solid tumors: Ca-755 adenocarcinoma of the mammary gland, Lewis adenocarcinoma of the lung, and S180 sarcoma. The positions and intensities of the Cotton effects in CD spectra of the MP-2 peptide and its retro-analogue in various solvents are almost indistinguishable. The positions of extrema and integral intensities of the amide I and amide A bands in IR spectra of both peptides were practically identical.__________Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 3, 2005, pp. 239–244.Original Russian Text Copyright © 2005 by Fonina, Ovchinnikov, Gur’yanov, Sychev, Belevskaya, Treshchalina.     

Hybrid and Monosomic Analyses of Smoky Coloration of the Ear in Common Wheat

The results of the hybrid and monosomic analyses of smoky ear coloration in the common wheat variety columbina are reported. The character has been found to be monogenic, and its gene has been located to chromosome 1DS. The smoky ear coloration is determined by an allele of gene Rg2 introgressed to wheat from Aegilops tauschii.__________Translated from Genetika, Vol. 41, No. 8, 2005, pp. 1147–1149.Original Russian Text Copyright © 2005 by Pshenichnikova, Bokarev, Shchukina.     

Phylogeny of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Genes in Haloalkaliphilic Obligately Autotrophic Sulfur-Oxidizing Bacteria of the Genus <Emphasis Type="Italic">Thioalkalivibrio</Emphasis>

Fragments of genes of the “green-like” form I ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) of eight species of haloalkaliphilic obligately autotrophic sulfur-oxidizing bacteria of the genus Thioalkalivibrio have been revealed and sequenced using previously developed oligonucleotide primers. The data obtained are used for the construction of phylogenetic trees on the basis of nucleotide sequences of RuBisCO genes and their conceptual translations into amino acid sequences. Comparative analysis of the 16S rRNA and RuBisCO gene trees reveals discrepancies between their topologies. According to a RuBisCO gene analysis, the genus Thioalkalivibrio is not monophyletic, and its inner divergence conforms to the significant morphological differences observed between the species. Presumably, horizontal (interspecies) gene transfer was involved in the evolution of the genus Thioalkalivibrio.__________Translated from Mikrobiologiya, Vol. 74, No. 3, 2005, pp. 378–386.Original Russian Text Copyright © 2005 by Tourova, Spiridonova, Berg, Kuznetsov, Sorokin.     

A Synthesis of Tritium-Labeled Olanzapine

A synthesis of olanzapine, 2-methyl-10-(4-methyl-1-piperazinyl)-4H-thieno[2,3-b][1,5]benzodiazepine, was carried out and the conditions for its tritium labeling were optimized to obtain a tritium-labeled olanzapine preparation with a specific radioactivity of 12 Ci/mmol.__________Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 4, 2005, pp. 420–424.Original Russian Text Copyright © 2005 by Shevchenko, Nagaev, Kuznetsov, Polunin, Zozulya, Myasoedov.     

Egg allocation of the autoparasitoid encarsia tricolor at different relative densities of the primary host (Trialeurodes vaporariorum) and two secondary hosts (Encarsia formosa and E. tricolor)

Parasitism, offspring sex ratio and superparasitism of the facultative autoparasitoid Encarsia tricolor Foërster (Hymenoptera: Aphelinidae) when given access to arenae with different proportions of the primary host (Trialeurodes vaporariorum (Westwood)) and two species of secondary hosts (E. tricolor and Encarsia formosa Gahan) were studied.Parasitism and offspring sex ratio were not affected by female age in the range 3–10 days old. When the secondary hosts were young E. tricolor pupae, eggs were mostly laid on primary hosts, so the offspring sex ratio was more female-biased than expected, and secondary hosts were not superparasitized at all. When the secondary hosts were fully grown E. formosa larvae, superparasitism was small and offspring sex ratio was more male-biased than expected. E. tricolor females were able to discriminate between hosts previously parasitized by themselves and non-parasitized hosts.     

Time allocation of the parasitoidAphidius colemani (Hymenoptera: Aphidiidae) foraging forAphis gossypii (Homoptera: Aphidae) on cucumber leaves

The time allocation of individualAphidius colemani female parasitoids foraging forAphis gossypii nymphs on cucumber leaves has been investigated. Apart from experiences on the current leaf (such as density of hosts on the current leaf, density of hosts on a neighboring leaf and encounters with hosts on the current leaf), the effect of previous leaf visits on the time allocation was studied. Behavioral records were analyzed by means of the proportional hazards model, to determine the tendency of leaving the current leaf. The leaving tendency decreased only on leaves with a high host density (100 aphids), thus increasing the giving up time since the latest encounter. Rejection of aphids had no influence on the leaving tendency. To assess the effect of the number of hosts encountered on the leaving tendency, we considered three classes: 0–30 encounters, 31–100 encounters, and 100 or more encounters with hosts. The effect of the number of hosts encountered differed at different aphid densities. When fewer than 10 aphids were present the leaving tendency was much greater after 30 encounters than beforehand. At a density of 100 aphids the leaving tendency was lower than at the other aphid densities and increased only after 100 encounters. The density of hosts on a neighboring leaf, ranging from 0 to 100 hosts, had a negligible effect on the leaving tendency. Repeated visits to leaves with 10 unparasitized aphids resulted in an increase in the leaving tendency after 10 visits. It is argued that the parasitoids have some innate expectancy of host availability and that they concentrate on high-density patches.     

Effect of Thyrotropin-Releasing Hormone and Its Synthetic Analogue Digipramine on Certain Indices of Hemostasis <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in vivo</Emphasis>

The effect of neuropeptide thyrotropin-releasing hormone (TRH) and its synthetic analogue digipramine on certain indices of blood coagulation and fibrinolysis were studied in vitro and in vivo. The peptides added to the pool of normal rat plasma at 10⁻¹⁰ to 10⁻³ M increased the procoagulant activity but had virtually no effect on fibrinolysis. Intravenous administration of TRH and digipramine increased the procoagulant activity of the blood and platelet aggregation but decreased fibrinolysis; digipramine had a more pronounced effect on the coagulation potential of the blood and a less pronounced effect on fibrinolytic indices as compared to TRH. Intranasal administration of the peptides did not change the pattern of their effect on indices of hemostasis although the effects became less pronounced.__________Translated from Izvestiya Akademii Nauk, Seriya Biologicheskaya, No. 3, 2005, pp. 311–315.Original Russian Text Copyright © 2005 by Grigorjeva, Golubeva.     

Role of <Emphasis Type="Italic">L</Emphasis>-phenylalanine ammonia Lyase in the induced resistance and susceptibility of sotato plants

Biogenic elicitors (chitosan and its complex with salicylic acid) and an immunosuppressor (laminarin) were shown to increase the activity of L-phenylalanine ammonia lyase (EC 4.3.1.5) and protein synthesis in potato tubers. Laminarin did not decrease L-phenylalanine ammonia lyase activity. It is unlikely that the activity of this enzyme serves as a criterion for the induced resistance.Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 1, 2005, pp. 117–120.Original Russian Text Copyright © 2005 by Gerasimova, Pridvorova, Ozeretskovskaya.     

Serotoninergic Mechanism in the Central Link of the Shadow Reflex in <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis> L.

The study was performed on effects of serotonin and its antagonists (mianserin, propranolol, and metergoline) on efferent electrical activity in nerves cervicalis superior, cervicalis inferior, and columellaris innervating muscles withdrawing body of Lymnaea stagnalis into the shell. Serotonin had a dual effect on the off-reactions caused by rhythmical light stimulation of mollusc skin. The number of responses to series of stimuli increased at serotonin concentrations of about 10⁻⁸-10⁻⁷ M and decreased at its higher concentrations. In many cases, serotonin antagonists also had a dual effect depending on their concentration. All studied substances slightly affected duration and latent period of individual off-responses. Serotoninergic regulation is suggested to participate in central chains of the pond snail defensive shadow reflex.__________Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 41, No. 2, 2005, pp. 134–138.Original Russian Text Copyright © 2005 by Samarova, Zhukov, Sudoplatov.     

First occurrence of Cochlodinium blooms in Sabah, Malaysia

Harmful algal blooms (HABs) resulting in red discoloration of coastal waters in Sepanggar Bay, off Kota Kinabalu, Sabah, East Malaysia, were first observed in January 2005. The species responsible for the bloom, which was identified as Cochlodinium polykrikoides, coincided with fish mortalities in cage-cultures. Determinations of cell density between January 2005 and June 2006 showed two peaks that occurred in March–June 2005 and June 2006. Cell abundance reached a maximum value of 6 × 10⁶ cells L⁻¹ at the fish cage sampling station where the water quality was characterized by high NO₃–N and PO₄–P concentrations. These blooms persisted into August 2005, were not detected during the north–east monsoon season and occurred again in May 2006. Favorable temperature, salinity and nutrient concentrations, which were similar to those associated with other C. polykrikoides blooms in the Asia Pacific region, likely promoted the growth of this species. Identification of C. polykrikoides as the causative organism was based on light and scanning microscopy, and confirmed by partial 18S ribosomal DNA sequences of two strains isolated during the bloom event (GenBank accession numbers DQ915169 and DQ915170).