Nuclease Digestion of Chromatin from the Eukaryotic Algae Olisthodiscus luteus,Peridinium balticum,and Crypthecodinium cohnii 1, 2

Chromatin from a uninucleate dinoflagellate, Crypthecodinium cohnii, a binucleate dinoflagellate, Peridinium balticum, and a chromophyte, Olisthodiscus luteus, was examined by nuclease digestion and the results were compared to those from vertebrates. Gel analysis of the products of staphylococcal (micrococcal) nuclease digestion revealed a DNA repeat unit of 220(±5) base pairs for O. luteus and 215(±5) for P. balticum. Limit digestion gave a core particle of 140 base pairs, revealing that these longer repeat sizes are due to longer linker regions. No repeating subunit structure was found upon electrophoresis of digests of C. cohnii nuclei. Examination of the DNA fragments produced by DNAse I digestion of nuclei isolated from P. balticum and O. luteus showed the same ladder of ten base multiples as seen in chromatin from other eukaryotes. Examination of the kinetics of digestion by DNAse II of Peridinium chromatin revealed less susceptibility when compared to DNAse I digestions while 70% of Olisthodiscus chromatin and 35% of C. cohnii chromatin was sensitive to DNAse II. These data, taken together with previous results from Euglena, indicate that while algal chromatin is similar to that of higher eukaryotes in regard to DNAse I and II action, it differs in that the linker DNA is longer. In addition, the Hl-like histone from O. luteus and P. balticum is located in the linker DNA as in higher eukaryotes.     

Phylogenetic placement of the enigmatic parasite, <Emphasis Type="Italic">Polypodium hydriforme</Emphasis>, within the Phylum Cnidaria

Background  

Polypodium hydriforme is a parasite with an unusual life cycle and peculiar morphology, both of which have made its systematic position uncertain. Polypodium has traditionally been considered a cnidarian because it possesses nematocysts, the stinging structures characteristic of this phylum. However, recent molecular phylogenetic studies using 18S rDNA sequence data have challenged this interpretation, and have shown that Polypodium is a close relative to myxozoans and together they share a closer affinity to bilaterians than cnidarians. Due to the variable rates of 18S rDNA sequences, these results have been suggested to be an artifact of long-branch attraction (LBA). A recent study, using multiple protein coding markers, shows that the myxozoan Buddenbrockia, is nested within cnidarians. Polypodium was not included in this study. To further investigate the phylogenetic placement of Polypodium, we have performed phylogenetic analyses of metazoans with 18S and partial 28S rDNA sequences in a large dataset that includes Polypodium and a comprehensive sampling of cnidarian taxa.     

Combined effects of the entomopathogenic fungus, <Emphasis Type="Italic">Paecilomyces fumosoroseus</Emphasis> Apopka-97, and the generalist predator, <Emphasis Type="Italic">Dicyphus hesperus</Emphasis>, on whitefly populations

The effects of intraguild interactions between Dicyphus hesperus Knight (Hemiptera: Miridae) and Paecilomyces fumosoroseus Apopka-97 (PFR-97^TM) (Wize) Brown and Smith (Ascomycota: Hypocreales) on Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) populations were investigated in tomato greenhouse microcosms. Conditions were established in which interference or synergy would most likely occur; namely, a high number of available whiteflies were combined with large numbers of both D. hesperus and PFR-97^TM. We measured live whitefly density in a factorial repeated measures experiment where plants were provided or withheld releases of D. hesperus and/or applications of PFR-97^TM for 6 weeks. Releases of D. hesperus were made at a rate of 10 adults/plant during the first and third week and PFR-97^TM suspensions were applied with a backpack sprayer at a rate of 18 × 10⁷, 1.3 × 10⁷ and 1.2 × 10⁷ viable blastospores/ml during the first, third and fourth week, respectively. Results revealed a non-significant interaction effect between D. hesperus and PFR-97^TM, indicating that their actions were independent. Individual whitefly reductions of 48% and 35% were achieved by PFR-97^TM and D. hesperus, respectively. Collectively, the natural enemies reduced whitefly densities by 62% relative to the controls. The density of D. hesperus adults was unaffected by multiple applications of PFR-97^TM. These results suggest that the combination of generalist entomopathogenic fungi and generalist predators has the potential to cause increased pest mortality despite evidence of minimal interference.     

Diurnal rhythmic expression of the rhythm-related genes, <Emphasis Type="Italic">rPeriod1, rPeriod2,</Emphasis> and <Emphasis Type="Italic"> rClock</Emphasis>, in the rat brain

High densities of the mRNA of three rhythm-related genes, rPeriod1 (rPer1), rPer2, and rClock, which share high homology in Drosophila and mammals, are found in the rat hypothalamic suprachiasmatic nucleus (SCN). The SCN, however, is not the only brain region that expresses these genes. To understand the possible physiological roles of these rhythm-related genes, we examined expression of these genes in different brain regions at various time points in male Sprague--Dawley rats. Using semi quantitativein situ hybridization with ³⁵S-riboprobes to evaluate mRNA levels, the diurnal rhythmicity of rPer1, and rPer2 mRNA levels was found in the SCN, arcuate nucleus, and median eminence/pars tuberalis. Expression patterns of mRNA for rPer1 and rPer2, however, were not similar in these brain regions. The rhythmicity in these brain regions was specific, because it was not observed in the cerebellum or hippocampus. Moreover, diurnal changes in rClock mRNA expression were not detected in any of the brain regions examined. These findings suggest that the different expression patterns observed for rPer1, rPer2, and rClock mRNAs may be attributed to their different physiological roles in these brain regions, and support previous work indicating that circadian rhythms in the brain are widespread.     

Cold hardiness,adaptive strategies,and invasion of slugs of the genus <Emphasis Type="Italic">Deroceras</Emphasis> (Gastropoda,Pulmonata) in northeastern Asia

Abstract-Four species of slugs have been identified in the vicinity of Magadan: Deroceras laeve, D. altaicum, D. reticulatum, and D. agreste. They exemplify three different life cycle schemes, with D. reticulatum and D. altaicum wintering at the egg phase; D. laeve, at the slug phase; and D. agreste, at either phase. The D. altaicum and D. reticulatum slugs and D. laeve eggs are intolerant of subzero temperatures. D. laeve’s tolerate freezing and survive at temperatures below −28°C. The eggs of other species, which lose up to 35% of water upon cooling, can withstand temperatures as low as −15 to −17°C (D. altaicum), −25°C (D. agreste), and −35°C (D. reticulatum). According to preliminary data, D. agreste slugs survive at temperatures down to −10°C. The almost ubiquitous distribution of D. laeve in regions with cool summers (including zonal tundras) is accounted for not so much by the high rate of ontogeny as by its significant cold hardiness and ability to winter at different phases of the life cycle (except for the egg phase), which allows the period of development to be prolonged for the next seasons. The last is confirmed by the fact that the slugs collected before and after hibernation proved to have identical patterns of distribution by body weight. Three species of slugs introduced in the vicinity of Magadan fail to spread inland. In the case of D. reticulatum, this is explained primarily by the fact that the frost-free season in inland areas is too short to allow these slugs to complete ontogeny and lay eggs. The barriers to their expansion appear to be insuperable, since this process remains unsuccessful over no less than 75–80 years.     

Vegetation of the aquatic and marshland habitats in the Orava region,including the first records of <Emphasis Type="Italic">Potametum alpini,Potametum zizii</Emphasis> and <Emphasis Type="Italic">Ranunculo-Juncetum bulbosi</Emphasis> in the territory of Slovakia

The vegetation of the aquatic and marshland habitats of the Orava region (north of Slovakia) was studied in 2009, using traditional phytosociological methods. Sixteen aquatic and eighteen marsh plant communities were described within 96 phytosociological relevés by using TWINSPAN with the application of the dominance principle. Three associations, Potametum alpini, Potametum zizii and Ranunculo-Juncetum bulbosi, were found as new communities for Slovakia. Myriophylletum verticillati, Potametum nodosi, Potametum graminei and Alisma gramineum community were recorded in the northernmost localities in Slovakia. Among marsh communities, Calletum palustris is very rare, both in the Orava region and in Slovakia as a whole. According to Ellenberg’s indicator values (EIV), moisture was evaluated as the main ecological gradient. Plant communities are ordered along the first Detrended Correspodence Analysis (DCA) axis in a typical hydroseries (Potametea → Lemnetea → Phragmition communis → Phalaridion arundinaceae, Oenanthion aquaticae and Sparganio-Glycerion → Magnocaricion elatae). The second DCA axis was most correlated with EIV for nutrients. Among the five directly measured ecological characteristics (temperature, pH and conductivity of water, water depth, and substrate type), conductivity of water (0.44, P < 0.01) and substrate type (0.32, P < 0.05) were the statistically significant variables explaining the variability along the first DCA axis.     

Contribution to the taxonomy,distribution and paleoecology of the early representatives of <Emphasis Type="Italic">Penthesilenula</Emphasis> Rossetti &; Martens, 1998 (Crustacea,Ostracoda, Darwinulidae) from Argentina,with the description of a new species

Early Mesozoic Argentinian darwinuloids, now re-assigned to the genus Penthesilenula (incae group), are described and illustrated. These records seem to constitute the oldest known for the genus. The close similarities between the studied species and those described from eastern Asia enlarge the geographical distribution of Penthesilenula (incae group), which, although restricted to the southern Hemisphere in Recent and Holocene times, may have had a wider distribution in the past. Additional information on the paleoecology, plus a preliminary account on the distribution of darwinulid species from Argentina are also offered. One new species is described: Penthesilenula loana sp. nov.     

Parasitoid complexes (Hymenoptera,Eulophidae) of leafminers of the genus <Emphasis Type="Italic">Phyllonorycter</Emphasis> (Lepidoptera,Gracillariidae) in the Middle Volga Basin

The parasitoid complexes of 22 species of the genus Phyllonorycter reared from 20 host plants were studied in the Middle Volga Basin. From a total of 124 host-parasitoid associations analyzed, 88 had been previously unknown. Minotetrastichus frontalis, Sympiesis sericeicornis, Pnigalio soemius, Closterocerus formosus, and S. gordius were the most frequent species. The highest percentage of parasitoids reared was observed in Ph. ulmifoliella (58.6%) and Ph. sylvella (54%), and the lowest one, in Ph. salictella (15%). Ph. corylifoliella (95.7%), Ph. populifoiella (95.5%) and Ph. insignitella (95.5%) had the highest mortality due to parasitoids. The number of endoparasitoid species prevailed over that of ectoparasitoids in the parasitoid complexes of the genus Phyllonorycter, but the number of individuals reared was 4 times greater for ectoparasitoids. The parasitoid complexes were the most similar in Ph. harrisella and Ph. quercifoliella on Quercus robur. The gregarious ectoparasitoid M. frontalis predominated over parasitoids of Phyllonorycter.     

Colony growth and dispersal in the ant-tended aphid, <Emphasis Type="Italic">Aphis craccivora</Emphasis> Koch,and the non-ant-tended aphid, <Emphasis Type="Italic">Acyrthosiphon pisum</Emphasis> Harris,under the absence of predators and ants

To elucidate the potential for colony growth and the dispersal of aphids in relation to the ant attendance, the mobility, tolerance of starvation, colony growth, and dispersal were examined in the ant-tended Aphis craccivora Koch and the non-ant-tended Acyrthosiphon pisum Harris under the absence of predators and ants. The increase of the dispersal rate with density was more conspicuous in Ac. pisum than Ap. craccivora. The success rate of dispersal was higher in Ac. pisum than Ap. craccivora. These results would be derived from the higher ability of dispersal by walking in Ac. pisum than Ap. craccivora. The longer legs, higher walking speed, and stronger tolerance of starvation in Ac. pisum might result in a higher ability of dispersal by walking. These traits may have developed in relation to non-ant attendance, because Ac. pisum aphids frequently escape from natural enemies by dropping from the host plant. On the other hand, Ap. craccivora have not developed morphological and behavioral traits concerning dispersal by walking, because increasing colony size without dispersal is likely to be advantageous for ant attraction. Escaping behaviors of Ap. craccivora from natural enemies have not been well developed due to the ant’s defense against natural enemies. The proportion of alatae in Ap. craccivora was higher than in Ac. pisum instead of a lesser ability for dispersal by walking in Ap. craccivora. The differences in ant attendance have been influenced in the development of morphological and behavioral traits concerning the dispersal ability, and then, different potentials for reproduction and dispersal have developed in ant-tended aphids and non-ant-tended aphids.     

Bees of the genus <Emphasis Type="Italic">Rophites</Emphasis> Spinola (Hymenoptera,Halictidae, Rophitinae) of Russia and adjacent territories

An illustrated key to Rophites species and an annotated list of 9 species from Russia and adjacent territories are given. Rophites clypealis stepposus subsp. n. and the female of R. schoenitzeri Dubitzky, 2004 are described. Lectotypes of Rhophites caucasicus Morawitz, 1876 and Rh. mandibularis Morawitz, 1891 are designated. Rophites algirus is recorded for the first time from Armenia; R. caucasicus, from Azerbaijan; R. clypealis, from Bulgaria, Russia, and Kazakhstan; R. foveolatus, from Georgia; R. quinquespinosus, from Armenia and Uzbekistan; R. schoenitzeri, from Azerbaijan and Iran.     

A 70-kDa molecular chaperone,DnaK, from the industrial bacterium <Emphasis Type="Italic">Bacillus licheniformis</Emphasis>: gene cloning,purification and molecular characterization of the recombinant protein

The heat shock protein 70 (Hsp70/DnaK) gene of Bacillus licheniformis is 1,839 bp in length encoding a polypeptide of 612 amino acid residues. The deduced amino acid sequence of the gene shares high sequence identity with other Hsp70/DnaK proteins. The characteristic domains typical for Hsps/DnaKs are also well conserved in B. licheniformis DnaK (BlDnaK). BlDnaK was overexpressed in Escherichia coli using pQE expression system and the recombinant protein was purified to homogeneity by nickel-chelate chromatography. The optimal temperature for ATPase activity of the purified BlDnaK was 40°C in the presence of 100 mM KCl. The purified BlDnaK had a V _max of 32.5 nmol Pi/min and a K _M of 439 μM. In vivo, the dnaK gene allowed an E. coli dnaK756-ts mutant to grow at 44°C, suggesting that BlDnaK should be functional for survival of host cells under environmental changes especially higher temperature. We also described the use of circular dichroism to characterize the conformation change induced by ATP binding. Binding of ATP was not accompanied by a net change in secondary structure, but ATP together with Mg²⁺ and K⁺ ions had a greater enhancement in the stability of BlDnaK at stress temperatures. Simultaneous addition of DnaJ, GrpE, and NR-peptide (NRLLLTG) synergistically stimulates the ATPase activity of BlDnaK by 11.7-fold.     

Comparative study of the expression of the native,modified, and hybrid <Emphasis Type="Italic">cry</Emphasis>3a genes of <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> in prokaryotic and eukaryotic cells

The cry3a gene of Bacillus thuringiensis was cloned. Based on sequence analysis of this gene, a modified gene, cry3aM, was constructed, which has the optimal codon composition for effective expression in eukaryotic cells. Hybrid genes cry3a-licBM2 and cry3aM-licBM2 were constructed, in which the sequences of the native and modified genes are fused with the reporter gene for thermostable lichenase in the reading frame. We have shown that the expression levels of hybrid genes cry3a-licBM2 and cry3aM-licBM2 in Escherichia coli are comparable, being 5% of those for reporter gene licBM2. In cells of a lower eukaryote Saccharomyces cerevisiae, the expression of hybrid gene cry3aM-licBM2, which contains the modified gene, considerably exceeded the level of expression of cry3a-licBM2 containing the native gene. The presence of lichenase in the composition of hybrid proteins was shown to facilitate selection and analysis of the expression level of hybrid proteins in transgenic organisms.Translated from Genetika, Vol. 41, No. 2, 2005, pp. 171–177.Original Russian Text Copyright © 2005 by Salehi Jozani, Komakhin, Piruzian.     

Characterization of the plasticity‐related gene,Arc, in the frog brain

In mammals, expression of the immediate early gene Arc/Arg3.1 in the brain is induced by exposure to novel environments, reception of sensory stimuli, and production of learned behaviors, suggesting a potentially important role in neural and behavioral plasticity. To date, Arc has only been characterized in a few species of mammals and birds, which limits our ability to understand its role in modifying behavior. To begin to address this gap, we identified Arc in two frog species, Xenopus tropicalis and Physalaemus pustulosus, and characterized its expression in the brain of P. pustulosus. We found that the predicted protein for frog Arc shared 60% sequence similarity with Arc in other vertebrates, and we observed high Arc expression in the forebrain, but not the midbrain or hindbrain, of female túngara frogs sacrificed at breeding ponds. We also examined the time‐course of Arc induction in the medial pallium, the homologue of the mammalian hippocampus, in response to a recording of a P. pustulosus mating chorus and found that accumulation of Arc mRNA peaked 0.75 h following stimulus onset. We found that the mating chorus also induced Arc expression in the lateral and ventral pallia and the medial septum, but not in the striatum, hypothalamus, or auditory midbrain. Finally, we examined acoustically induced Arc expression in response to different types of mating calls and found that Arc expression levels in the pallium and septum did not vary with the biological relevance or acoustic complexity of the signal. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70: 813–825, 2010     

Epibiotic demosponges on the Antarctic scallop <Emphasis Type="Italic">Adamussium colbecki</Emphasis> (Smith, 1902) and the cidaroid urchins <Emphasis Type="Italic">Ctenocidaris perrieri</Emphasis> Koehler, 1912 in the nearshore habitats of the Victoria Land,Ross Sea,Antarctica

The importance of epibiosis in Antarctic benthic communities is highlighted here considering the specific diversity of sponges living on shells of the scallop Adamussium colbecki and on spines of the cidaroid urchin Ctenocidaris perrieri. Scallops are from three different areas along the Victoria Land [Tethys Bay (TB), New Harbour (NH), Dunlop Island (DI)], while cidaroid urchins are from NH but not present in the two other stations. Homaxinella balfourensis is the commonest species both on the scallops and cidaroid urchins. Other common species on scallops are Myxilla (Myxilla) asigmata, Lissodendoryx (Ectyodoryx) nobilis and Iophon unicorne at NH, Iophon unicorne at DI, and Iophon radiatum, Haliclona sp. 1, Iophon unicorne and Lissodendoryx (Ectyodoryx) nobilis at TB. The highest number of sponge species we found on a single scallop was ten and the sample was collected at NH. On the spines of C. perrieri, Isodictya erinacea, Iophon unicorne and Haliclona (Rhizoniera) dancoi are present too. A. colbecki and C. perrieri, generally living on soft bottoms, represent important substrata for several sponge species. In this way, sponges may increase their dispersal exploiting valves and spines as stepping stones.     

Cloning,expression, and PCR application of DNA polymerase from the hyperthermophilic archaeon, <Emphasis Type="Italic">Thermococcus celer</Emphasis>

The family B DNA polymerase gene was amplified from Thermococcus celer genomic DNA by using the degenerate primers and DNA walking PCR. The Tce DNA polymerase gene was cloned and sequenced. The gene contains an ORF of 2,325 bp encoding 774 amino acid residues with a calculated molecular weight of 89,788.9 kDa. The Tce DNA polymerase was purified by heat treatment and heparin column chromatography. The optimal conditions for PCR were determined. Long-range PCR and time-saving PCR were performed using various specific ratios of Taq and Tce DNA polymerases (Tce plus DNA polymerase). Tce plus DNA polymerase surpassed the PCR performance of Tce, Taq and Pfu DNA polymerases in terms of yield and efficiency.     

Length–weight relationships of two catfish species from the Guareí River basin,São Paulo,Brazil

Here the length–weight relationships (LWRs) of two catfish species are provided. Individuals of Imparfinis mirini Haseman, 1911, and Phenacorhamdia tenebrosa (Schubart, 1964) were collected in August and December 2017 from the Guareí River Basin, upper Paraná River basin, Brazil. Values of b were between 2.66 and 3.11 and a between 0.0122 and 0.0137; statistical analysis showed high r² values. Lastly, a new record of maximum standard length for P. tenebrosa is provided.     

Host plant preferences of Hyalesthes obsoletus,the vector of the grapevine yellows disease ‘bois noir’, in Switzerland

Bois noir is an important grapevine yellows disease in Europe that can cause serious economic losses in grapevine production. It is caused by stolbur phytoplasma strains of the taxonomic group 16Sr‐XII‐A. Hyalesthes obsoletus Signoret (Hemiptera: Cixiidae) is the most important vector of bois noir in Europe. This polyphagous planthopper is assumed to mainly use stinging nettle [Urtica dioica L. (Urticaceae)] and field bindweed [Convolvulus arvensis L. (Convolvulaceae)] as its host plants. For a better understanding of the epidemiology of bois noir in Switzerland, host plant preferences of H. obsoletus were studied in the field and in the laboratory. In vineyards of Western Switzerland, adults of H. obsoletus were primarily captured on U. dioica, but a few specimens were also caught on C. arvensis, hedge bindweed [Calystegia sepium (L.) R. Brown (Convolvulaceae)], and five other dicotyledons [i.e., Clematis vitalba L. (Ranunculaceae), Lepidium draba L. (Brassicaceae), Plantago lanceolata L. (Plantaginaceae), Polygonum aviculare L. (Polygonaceae), and Taraxacum officinale Weber (Asteraceae)]. The preference of the vector for U. dioica compared to C. arvensis was confirmed by a second, more targeted field study and by the positioning of emergence traps above the two plant species. Two‐choice experiments in the laboratory showed that H. obsoletus adults originating from U. dioica preferred to feed and to oviposit on U. dioica compared to C. arvensis. However, H. obsoletus nymphs showed no host plant preference, even though they developed much better on U. dioica than on C. arvensis. Similarly, adults survived significantly longer on U. dioica than on C. arvensis or any other plant species tested [i.e., L. draba and Lavandula angustifolia Mill. (Lamiaceae)]. In conclusion, although nymphs of H. obsoletus had no inherent host plant preference, adults tested preferred to feed and oviposit on U. dioica, which is in agreement with the observed superior performance of both nymphal and adult stages on this plant species. Urtica dioica appears to be the principal host plant of H. obsoletus in Switzerland and plays therefore an important role in the epidemiology of the bois noir disease in Swiss vineyards.     

Comparative osteology,relationships, and systematics of fish of the genus <Emphasis Type="Italic">Zoarces</Emphasis> (Zoarcidae,Perciformes)

Comparative-osteological investigation of all species of the genus Zoarces is made: Z. fedorovi, Z. andriashevi, Z. elongatus, Z. viviparus, Z. americanus, and Z. gillii. In the skeleton of hyoid arch in species of Zoarces, Lycozoarces, and Lycodes, paired bony elements are found, not described previously, identified as parurohyalia which may be synapomorphy of Zoarcidae. Differences between the Zoarces species are revealed by 56 external morphological and osteological characters. Cladistic analysis yielded one tree 135, Ci 0.57, Ri 0.54 long. Cladistic analysis confirms validity of a recently described species Z. fedorovi, which turned out to be the most generalized in the genus Zoarces, as well as the validity of Z. elongatus. The species Z. americanus and Z. gillii occupy a terminal position preventing their isolation to independent genera as was previously supposed, as this would lead to paraphyly of the genus Zoarces.