Geographic variability of morphogenetic diapause in larvae and nymphs of the taiga tick <Emphasis Type="Italic">Ixodes persulcatus</Emphasis> (Acarina,Ixodidae)

The critical day length inducing morphogenetic diapause in engorged larvae and nymphs of the taiga tick Ixodes persulcatus Schulze, 1930 was shown to vary with both latitude and longitude. Intraspecific differences in ecological responses of larvae and nymphs to the day length were most pronounced in the latitudinal direction. The critical day length was 13.5–14.5 h in the southern part of the species range (40–43°N) and up to 18–19 h in its northern part (62°N). Longitudinal variation is closely linked to the severity of the climate increasing from west to east. It was demonstrated for the first time that mass diapause induction in nymphs may occur not only during the period of decreasing day length but also during the summer solstice, the latter variant being observed only in the sharply continental climate of Eastern Siberia. Adaptive advantages of this photoperiodic response under the conditions of a short summer are discussed. Diapause in ticks occurs in response to environmental factors, such as changes in the photoperiod, and represents the main adaptation by which ticks synchronize their activity with biotic resources.     

Differential diagnosis of <Emphasis Type="Italic">Ixodes ricinus</Emphasis> and <Emphasis Type="Italic">Ixodes persulcatus</Emphasis>: nymphs and larvae

We developed a method for differential diagnosis of nymphs and larvae of sheep (Ixodes ricinus (L.)) and taiga (I. persulcatus Sch.) ticks (Parasitiformes: Ixodidae) which allows to identify live material in the field.     

Detection of <Emphasis Type="Italic">Borrelia miyamotoi</Emphasis> in <Emphasis Type="Italic">Ixodes persulcatus</Emphasis> ticks in Russia

Unfed adult ticks Ixodes persulcatus from five regions of Russia were examined by PCR method in order to analyze distribution and diversity of B. miyamotoi. B. miyamotoi DNA was found in 1.8, 2.9, 4.5, 2.3, and 2.5% of ticks from Leningrad, Sverdlovsk, Novosibirsk, and Irkutsk provinces, and from Khabarovsk Territory, respectively. Molecular typing of B. miyamotoi DNA was based on the partial sequencing of the 16S rRNA, p66, and glpQ genes. A single genetic variant of B. miyamotoi was detected in all the samples of ticks collected from five regions.     

Parasitological factors impeding transmission of the babesiosis pathogen <Emphasis Type="Italic">Babesia microti</Emphasis> from the tick <Emphasis Type="Italic">Ixodes persulcatus</Emphasis> to humans

Based on analysis of original and literature data, it is concluded that effective transmission of B. microti by the tick I. persulcatus is prevented by the following main permanent eco-parasitological factors: lack of pronounced anthropophily in the tick nymphs; low rates of spontaneous invasion of unfed adults; a short duration of the parasitic phase on humans which is not sufficient for completion of sporogony. Therefore, in spite of the possibility of sporadic cases of babesiosis, it can be stated that B. microti infection does not and will not play a significant role in infectious pathology within the vast territory where the taiga tick is the only potential source of this infection.     

The First Data on the <Emphasis Type="Italic">TROSPA</Emphasis> Gene Structure in <Emphasis Type="Italic">Ixodes persulcatus</Emphasis> and <Emphasis Type="Italic">Ixodes ricinus</Emphasis> Ticks from Russia

For the first time, the sequences of the TROSPA gene from taiga tick and sheep tick from Russia were obtained. Three specimens of sheep tick from Voronezh oblast and three specimens each of taiga tick from Irkutsk oblast and Perm krai were analyzed. At the end of the intron of the TROSPA gene in Ixodes persulcatus, a poly-T region was found. In addition, a fragment of the first exon containing a large number of differences in the nucleotide and amino acid composition both among species and within them was identified.     

Evidence of <Emphasis Type="Italic">Babesia microti</Emphasis> infection in multi-infected <Emphasis Type="Italic">Ixodes persulcatus</Emphasis> ticks in Russia

To detect Babesia-infected Ixodes persulcatus Shulze in a suburb of St. Petersburg, Russia, 738 adult ticks were studied using Babesia specific primers and PCR techniques. The entire sample (more than 1,200 individuals) was screened for the presence of Borrelia spp., Ehrlichia spp. and tick-borne encephalitis virus (TBEV). All 7 ticks infected with Babesia microti, were also infected with other pathogens (all 7 among 417 infected ticks, zero amongst the remaining 321 naive ones (χ² = 5.25, p < 0.05). Babesia microti occurred twice with Borrelia afzelii, 3 times with Borrelia garinii, once with both, and once with both B. garinii and TBEV. The prevalence of infection with Borrelia spp. was 34.0%, with Ehrlichia spp. 6.2%, with TBEV 1.5%, and with Ba microti 0.9%. Babesia microti infection was not found in combination with Ehrlichia sp. or Borrelia burgdorferi sensu stricto. The latter pathogen (prevalence 2.6%), just like Ba. microti, was not encountered as a monoinfection. The data suggest that Ba. microti infection can only survive in I. persulcatus in combination with Borrelia spp. (7 of 7 infections). The disease in humans is more severe and longer-lasting when more than one pathogen is involved. Our observations show that the well known St. Petersburg focus of tick-borne encephalitis and Lyme disease is also a focus of ehrlichiosis and babesiosis. This revised version was published online in July 2006 with corrections to the Cover Date.     

First record of the tick <Emphasis Type="Italic">Ixodes</Emphasis> (<Emphasis Type="Italic">Pholeoixodes</Emphasis>) <Emphasis Type="Italic">kaiseri</Emphasis> in Turkey

Nymphs and larvae belonging to Ixodes spp. were collected from a red fox in Turkey. The ticks were identified morphologically and molecularly (16S rDNA PCR and phylogenetic analysis) as I. kaiseri. Sequence and phylogenetic analyses show that our I. kaiseri isolate is very similar to I. kaiseri isolates collected from Germany, Serbia, Romania, and Hungary. Therefore, the existence of I. kaiseri has been demonstrated for the first time in Turkey. More studies relating to the regional distribution and vectorial competence of I. kaiseri are needed.     

Influence of Abiotic Factors on Different Developmental Stages of the Taiga Tick <Emphasis Type="Italic">Ixodes persulcatus</Emphasis> and the Sheep Tick <Emphasis Type="Italic">Ixodes ricinus</Emphasis>

This paper presents an analytical literature review of the effects of abiotic factors on the different developmental stages of the ixodid ticks Ixodes persulcatus and I. ricinus. These widespread species are generally well adapted to the potential variation gradient of the factors most important for their development, such as temperature and humidity, and also other environmental conditions. Their variation usually does not significantly affect the mortality of ticks at various “passive” stages of their development cycle. However, the number of generations of both species can vary if these factors influence the percentage of fully engorged diapausing individuals.     

Abundance of larvae and nymphs of the taiga tick <Emphasis Type="Italic">Ixodes persulcatus</Emphasis> Schulze (Acarina,Ixodidae) on small mammals in deforested areas in the middle taiga subzone of Karelia

The data on long-term studies (1998–2004) of the population density of preimaginal stages of the taiga tick Ixodes persulcatus Schulze, 1930 collected from small mammals in deforested areas (foresting during 7, 12, and 25 years after forest cutting) in the middle taiga zone of Karelia are given. The lowest population density of I. persulcatus was observed in the most recently deforested area. The territory where forestation lasted for 25 years after deforestation was the most favorable biotope for the taiga tick development. Deforested areas, in comparison with secondary forests, are characterized by significantly higher population density of preimaginal stages of ixodid ticks; this phenomenon is determined first of all by the high population density of small mammals.     

Ecological and molecular genetic features of <Emphasis Type="Italic">Ixodes persulcatus</Emphasis> and <Emphasis Type="Italic">I. pavlovskyi</Emphasis> ticks in Southern West Siberia

Ixodiae ticks have been counted and sampled in six distant locations within the Altai-Sayan Mountain Area and northern forest steppe in 2012. In total, 1829 individuals of I. persulcatus and 719 of I. pavlovskyi ticks were collected by flagging. I. persulcatus is found in all six examined locations and I. pavlovskyi is found in Western Altai, Northeastern Altai, and Northern Altai, as well as in forest parks near Akademgorodok of Novosibirsk. In total, 16S rRNA and COI sequences have been determined in 144 and 164 I. persulcatus individuals, as well as in 60 and 55 I. pavlovskyi. Selectively equivalent mutant forms are present in I. pavlovskyi populations of Northeastern Altai and Northern Altai. The hydrothermal regime in the forest parks near Novosibirsk is optimal for the I. pavlovskyi ticks. These ticks have recently colonized the forest parks near Novosibirsk and therefore are genetically close to I. pavloskyi from the Altai–Sayan Mountain Area populations.     

New combinations and typifications in <Emphasis Type="Italic">Bistorta</Emphasis>, <Emphasis Type="Italic">Persicaria</Emphasis>, <Emphasis Type="Italic">Polygonum,</Emphasis> and <Emphasis Type="Italic">Rumex</Emphasis> (Polygonaceae)

New combinations are proposed in anticipation of the Polygonaceae treatment in the forthcoming volume of Intermountain Flora: Polygonum kelloggii var. esotericum, P. kelloggii var. watsonii , Rumex densiflorus var. pycnanthus , R. salicifolius var. utahensis, and R. occidentalis var. tomentellus. Typifications are proposed to facilitate ongoing studies in Polygonaceae and to maintain current usage.     

<Emphasis Type="Italic">Rhipicephalus</Emphasis> (<Emphasis Type="Italic">Boophilus</Emphasis>) <Emphasis Type="Italic">microplus</Emphasis>: a most successful invasive tick species in West-Africa

The cattle tick Rhipicephalus (Boophilus) microplus is known to be a highly reproductive and efficient vector of Babesia bovis, two characters which make this tick a threat to livestock keeping in many continents. The authors identified this tick in Ivory Coast, West Africa, in 2007, and hypothesized the spread to be minimal, as this tick was not observed in previous years. To determine the extent of its distribution and to a lesser extent the possible impact of the tick on the livelihoods of Ivorian smallholders, a cross-sectional survey was carried out in the Abidjan and Agboville Departments of Ivory Coast, in April 2008. The results of the study reveal that the newly introduced tick has almost completely displaced all indigenous Rhipicephalus (Boophilus) species in the study area and gave rise to unsuccessful tick control, inappropriate pesticide use, loss of milk production and even increased mortality in dairy cattle.     

<Emphasis Type="Italic">Ty</Emphasis>1<Emphasis Type="Italic">/copia</Emphasis>- and <Emphasis Type="Italic">Ty</Emphasis>3<Emphasis Type="Italic">/gypsy</Emphasis>-like DNA sequences in <Emphasis Type="Italic">Helianthus </Emphasis>species

Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes.     

Revision of the <Emphasis Type="Italic">Serrulati</Emphasis> species of <Emphasis Type="Italic">Penstemon</Emphasis> section <Emphasis Type="Italic">Saccanthera</Emphasis> subsection <Emphasis Type="Italic">Serrulati</Emphasis>

A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations.     

<Emphasis Type="Italic">In silico</Emphasis> and <Emphasis Type="Italic">in situ</Emphasis> characterization of the zebrafish (<Emphasis Type="Italic">Danio rerio</Emphasis>) <Emphasis Type="Italic">gnrh3</Emphasis> (sGnRH) gene

Background

Gonadotropin releasing hormone (GnRH) is responsible for stimulation of gonadotropic hormone (GtH) in the hypothalamus-pituitary-gonadal axis (HPG). The regulatory mechanisms responsible for brain specificity make the promoter attractive for in silico analysis and reporter gene studies in zebrafish (Danio rerio).

Results

We have characterized a zebrafish [Trp⁷, Leu⁸] or salmon (s) GnRH variant, gnrh 3. The gene includes a 1.6 Kb upstream regulatory region and displays the conserved structure of 4 exons and 3 introns, as seen in other species. An in silico defined enhancer at -976 in the zebrafish promoter, containing adjacent binding sites for Oct-1, CREB and Sp1, was predicted in 2 mammalian and 5 teleost GnRH promoters. Reporter gene studies confirmed the importance of this enhancer for cell specific expression in zebrafish. Interestingly the promoter of human GnRH-I, known as mammalian GnRH (mGnRH), was shown capable of driving cell specific reporter gene expression in transgenic zebrafish.

Conclusions

The characterized zebrafish Gnrh3 decapeptide exhibits complete homology to the Atlantic salmon (Salmo salar) GnRH-III variant. In silico analysis of mammalian and teleost GnRH promoters revealed a conserved enhancer possessing binding sites for Oct-1, CREB and Sp1. Transgenic and transient reporter gene expression in zebrafish larvae, confirmed the importance of the in silico defined zebrafish enhancer at -976. The capability of the human GnRH-I promoter of directing cell specific reporter gene expression in zebrafish supports orthology between GnRH-I and GnRH-III.

     

Ontogeny of tick hemocytes: a comparative analysis of <Emphasis Type="Italic">Ixodes ricinus</Emphasis> and <Emphasis Type="Italic">Ornithodoros moubata</Emphasis>

Hemocytes of two tick species, Ixodes ricinus and Ornithodoros moubata, were investigated with the aim to determine their ultrastructural characteristics and developmental relationships. Only a limited number of ultrastructural features was shown to be unequivocally homological across all hemocyte types. The two species, representing distant groups of ticks, differ in the composition of their circular cell populations. In I. ricinus, three groups of distinct morphological types of hemocytes could be determined according to well-defined ultrastructural features: a typical non-phagocytic granular cell with electron-dense granula and homogeneous cytoplasm (Gr II), and two different types of phagocytic hemocytes, namely plasmatocytes with a low number of granula and phagocytic granolocytes, designated as Gr I. In contrast, an additional cell type resembling insect spherulocytes was determined in O. moubata. This cell type does not seem to be homologous to any I. ricinus hemocyte and may represent a cell type typical of soft ticks only. Possible ontogenetic lineages of the hemocytes of both tick-species were inferred.     

Pedogamy in <Emphasis Type="Italic">Neidium</Emphasis> (<Emphasis Type="Italic">Bacillariophyceae</Emphasis>)

Single (unpaired) vegetative cells of freshwater pennate diatom Neidium cf. ampliatum differentiated into gametangia and produced a single zygote (auxospore) via a pedogamic process. The gametic nuclei fused after auxospore expansion had begun. The auxospore expanded in parallel to the apical axis of the gametangium.     

Floral development and systematic position of <Emphasis Type="Italic">Arillastrum</Emphasis>, <Emphasis Type="Italic">Allosyncarpia</Emphasis>, <Emphasis Type="Italic">Stockwellia</Emphasis> and <Emphasis Type="Italic">Eucalyptopsis</Emphasis> (Myrtaceae)

We have investigated the floral ontogeny of Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis (of the eucalypt group, Myrtaceae) using scanning electron microscopy and light microscopy. Several critical characters for establishing relationships between these genera and to the eucalypts have been determined. The absence of compound petaline primordia in Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis excludes these taxa from the eucalypt clade. Post-anthesis circumscissile abscission of the hypanthium above the ovary in Stockwellia, Eucalyptopsis and Allosyncarpia is evidence that these three taxa form a monophyletic group; undifferentiated perianth parts and elongated fusiform buds are characters that unite Stockwellia and Eucalyptopsis as sister taxa. No floral characters clearly associate Arillastrum with either the eucalypt clade or the clade of Stockwellia, Eucalyptopsis and Allosyncarpia.We gratefully acknowledge Clyde Dunlop and Bob Harwood (Northern Territory Herbarium) for collecting specimens of Allosyncarpia, and Bruce Gray (Atherton) for collecting specimens of Stockwellia. The Australian National Herbarium (CANB) kindly lent herbarium specimens of Eucalyptopsis for examination. This research was supported by a University of Melbourne Research Development Grant to Andrew Drinnan.