Acquisition of Borrelia burgdorferi by Ixodes ricinus ticks fed on the European hedgehog,Erinaceus europaeus L

A hedgehog, Erinaceus europaeus, was found to be heavily infested with larval and nymphal Ixodes ricinus in a forest park in Co. Galway, Ireland. A large proportion of the ticks that engorged and detached were infected with the spirochacte, Borrelia burgdorferi, the causative agent of human Lyme borreliosis. The identity of these spirochaetes was confirmed by immunofluorescent assay with B. burgdorferi-specific monoclonal antibody and by polymerase chain reaction test and they were transmitted from the hedgehog to laboratory-reared ticks and from the ticks obtained from the hedgehog to gerbils (Meriones unguiculatus). The high infection rate of the larvae that fed on the hedgehog in comparison with unfed larvae from the same habitat was interpreted as strong evidence that this host species is reservoir competent. Since hedgehogs can evidently feed adult ticks as well as many immature stages, they may well have an important role in the ecology of Lyme borreliosis in some habitats.     

The evolution of the hedgehog gene family in chordates: insights from amphioxus hedgehog

 The hedgehog family of intercellular signalling molecules have essential functions in patterning both Drosophila and vertebrate embryos. Drosophila has a single hedgehog gene, while vertebrates have evolved at least three types of hedgehog genes (the Sonic, Desert and Indian types) by duplication and divergence of a single ancestral gene. Vertebrate Sonic-type genes typically show conserved expression in the notochord and floor plate, while Desert- and Indian-type genes have different patterns of expression in vertebrates from different classes. To determine the ancestral role of hedgehog in vertebrates, I have characterised the hedgehog gene family in amphioxus. Amphioxus is the closest living relative of the vertebrates and develops a similar body plan, including a dorsal neural tube and notochord. A single amphioxus hedgehog gene, AmphiHh, was identified and is probably the only hedgehog family member in amphioxus, showing the duplication of hedgehog genes to be specific to the vertebrate lineage. AmphiHh expression was detected in the notochord and ventral neural tube, tissues that express Sonic-type genes in vertebrates. This shows that amphioxus probably patterns its ventral neural tube using a molecular pathway conserved with vertebrates. AmphiHh was also expressed on the left side of the pharyngeal endoderm, reminiscent of the left-sided expression of Sonic hedgehog in chick embryos which forms part of a pathway controlling left/right asymmetric development. These data show that notochord, floor plate and possibly left/right asymmetric expression are ancestral sites of hedgehog expression in vertebrates and amphioxus. In vertebrates, all these features have been retained by Sonic-type genes. This may have freed Desert-type and Indian-type hedgehog genes from selective constraint, allowing them to diverge and take on new roles in different vertebrate taxa. Received: 20 July 1998 / Accepted: 23 September 1998     

Comparative population dynamics of a generalist (<Emphasis Type="Italic">Ixodes ricinus</Emphasis>) and specialist tick (<Emphasis Type="Italic">I. hexagonus</Emphasis>) species from European hedgehogs

Although the population dynamics of the tick Ixodes ricinus are relatively well studied, those of other Western European tick species are largely unknown. Moreover, there is very little information related to the interactions between I. ricinus and other ticks. Such knowledge, however, is of special interest in respect to the epidemiology of tick-borne pathogens such as Borrelia spp. We compared the dynamics of the generalist I. ricinus with the nest-dwelling hedgehog specialist, I. hexagonus. Both species were collected from hedgehogs from a naturally infested experimental population between 2006 and 2008. Ticks were collected once a month from March to October from each hedgehog counted and the life history stage and species determined. All hedgehogs harboured both tick species. Nymphs, females and males of I. ricinus showed clear bimodal seasonal distributions with peaks in spring and autumn, while larvae peaked only in summer. The density of I. hexagonus life stages was low during the whole investigation period and seasonal fluctuations of population density were much weaker compared to I. ricinus. Nymphs and larvae showed comparatively little change in population size and no consistent period of peak density. Females showed a single peak in summer and males were found only occasionally on hedgehogs. We suggest density-dependent mechanisms regulating the population density of the specialist I. hexagonus but not of the generalist I. ricinus.     

National predictors of hedgehog Erinaceus europaeus distribution and decline in Britain

We utilise a volunteer survey recording roadkills between 2001 and 2011 to examine the factors affecting hedgehog Erinaceus europaeus abundance and decline. Hedgehogs were most abundant in the North and East of England and in Scotland, regions characterised by low badger numbers. Hedgehogs selected arable land and urban areas relative to their availability. Badger Meles meles and fox Vulpes vulpes abundance were negatively associated with hedgehog abundance at the 10 km² scale. At the county level, foxes were positively associated with hedgehog numbers and badgers negatively associated. The mechanism behind the relationships between hedgehogs and badgers and foxes merits further investigation.     

BMP-2 functions independently of SHH signaling and triggers cell condensation and apoptosis in regenerating axolotl limbs

Background  

Axolotls have the unique ability, among vertebrates, to perfectly regenerate complex body parts, such as limbs, after amputation. In addition, axolotls pattern developing and regenerating autopods from the anterior to posterior axis instead of posterior to anterior like all tetrapods studied to date. Sonic hedgehog is important in establishing this anterior-posterior axis of limbs in all tetrapods including axolotls. Interestingly, its expression is conserved (to the posterior side of limb buds and blastemas) in axolotl limbs as in other tetrapods. It has been suggested that BMP-2 may be the secondary mediator of sonic hedgehog, although there is mounting evidence to the contrary in mice. Since BMP-2 expression is on the anterior portion of developing and regenerating limbs prior to digit patterning, opposite to the expression of sonic hedgehog, we examined whether BMP-2 expression was dependent on sonic hedgehog signaling and whether it affects patterning of the autopod during regeneration.     

Second generation experimental hybridizations in theEchinocereus ×lloydii complex (Cactaceae), and further documentation of dioecy inE. coccineus

Artificial second generation and backcross hybrids involvingEchinocereus dasyacanthus (Texas rainbow cactus),E. coccineus (a species of claret-cup cactus), andE. ×lloydii (Lloyd's hedgehog cactus) were examined for morphological and reproductive characteristics. The hybrids grew from seed to flower in about four years, and they exhibited high fertility as measured by pollen stainability, crossability, and fruit-set. A rare breeding system inCactaceae, dioecy, was further examined inE. coccineus, using field and controlled pollination tests. Functional dioecy was documented forE. coccineus in Trans-Pecos Texas. All results suggested thatE. ×lloydii in eastern Pecos County, Texas, is a complex and dynamic population probably comprising first and later generation hybrids, including backcross hybrids. The experimental hybridizations also tended to support the occurrence of introgression into both putative parental species.     

Functional role of hedgehog pathway in osteoarthritis

The hedgehog signalling pathway is one of the key regulators of metazoan development, and it plays an important role in the regulation of a variety of developmental and physiological processes. But it is aberrantly activated in many human diseases, including osteoarthritis (OA). In this study, we have reviewed the association of hedgehog signalling pathway in the development and progression of OA and evaluated the efforts to target this pathway for the prevention of OA. Usually in OA, activation of hedgehog induces up-regulation of the expression of hypertrophic markers, including type X collagen, increases production of nitric oxide and prostaglandin E2, several matrix-degrading enzymes including matrix metalloproteinase and a disintegrin and metalloproteinase with thrombospondin motifs in human knee joint cartilage leading to cartilage degeneration, and thus contributes in OA. Targeting hedgehog signalling might be a viable strategy to prevent or treat OA. Chemical inhibitors of hedgehog signalling is promising, but they cause severe side effects. Knockdown of HH gene is not an option for OA treatment in humans because it is not possible to delete HH in larger animals. Efficient knockdown of HH achieved by local delivery of small interfering RNA in future studies utilizing large animal OA models might be a more efficient approach for the prevention of OA. However, it remains a major problem to develop one single scaffold due to the different physiological functions of cartilage and subchondral bones possess. More studies are necessary to identify selective inhibitors for efficiently targeting the hedgehog pathway in clinical conditions.     

Caucasus Mountains divide postulated postglacial colonization routes in the white‐breasted hedgehog,Erinaceus concolor

For many European species, the mountains of the Alps and the Pyrenees have acted as significant barriers to northwards colonization from southern glacial refugia. To the east, the Caucasus Mountains would seem to have been a similar barrier to the white‐breasted hedgehog (Erinaceus concolor). A deep divergence among hedgehog mitochondrial sequences to the north and south of the Caucasus Mountains suggests two colonization routes, originating from separate refugial regions and divided by this mountain barrier. From a Balkan refugium, hedgehogs have colonized northwards into Russia and to the northern foothills of the Caucasus Mountains. The origins of hedgehogs colonizing the southern parts of the Caucasus are not entirely clear, although fossil and climatic data suggest a glacial refugium on the southern shores of the Black Sea. Divergence within the southern group indicates a long‐standing fragmentation within such a refugium or the presence of further cryptic refugia in Turkey and the Near East. The Caucasus barrier would seem to have been an important factor in structuring the late Pleistocene distribution of species.     

FUNCTIONAL DIOECY IN ECHINOCEREUS COCCINEUS (CACTACEAE): BREEDING SYSTEM,SEX RATIOS,AND GEOGRAPHIC RANGE OF FLORAL DIMORPHISM

The breeding system of the hedgehog cactus, Echinocereus coccineus Engelm. (Cactaceae), was studied at two sites in the northern Chihuahuan Desert, New Mexico. Two distinct flower types, restricted to separate plants, were observed. One was hermaphroditic and the other male-sterile. Hand-pollinations and field observations showed them to be functionally male and functionally female, respectively. There were significant quantitative intersexual differences in floral morphology. The main pollinators of the populations studied are probably two species of halictid bee. Sex ratios based on the number of plants and flowers at the two sites did not differ significantly from 1:1. Significant differences in fruit set existed between functional female plants from the two sites. The floral dimorphism described here appears confined to eastern and northwestern populations, at the periphery of the range of E. coccineus. Floral dimorphism was not observed in three closely related species.     

Synthesis and Evaluation of Aminothiazole Derivatives as Hedgehog Pathway Inhibitors

A series of aminothiazole derivatives bearing the benzimidazole moiety were synthesized and evaluated in Gli luciferase reporter assays. Lead optimization led to the discovery of potent hedgehog pathway antagonist 18 (2‐[3‐(1H‐benzimidazol‐2‐yl)‐4‐chloroanilino]‐N‐[4‐(trifluoromethyl)phenyl]‐1,3‐thiazole‐4‐carboxamide), with IC₅₀ values in nanomolar range. The molecular basis ascribed to hindering sonic hedgehog‐driven Smoothened (Smo) localization within the primary cilium (PC). Moreover, compound 18 inhibited Gli1 mRNA expression in mutant Smo cell line and displayed moderate cytotoxicity against DAOY cancer cell.     

Infestation of urban populations of the Northern white‐breasted hedgehog,Erinaceus roumanicus,by Ixodes spp. ticks in Poland

Infestation by the nest‐dwelling Ixodes hexagonus Leach and the exophilic Ixodes ricinus (Linnaeus) (Ixodida: Ixodidae) on the Northern white‐breasted hedgehog, Erinaceus roumanicus (Erinaceomorpha: Erinaceidae), was investigated during a 4‐year study in residential areas of the city of Poznań, west‐central Poland. Of 341 hedgehogs, 303 (88.9%) hosted 10 061 Ixodes spp. ticks encompassing all parasitic life stages (larvae, nymphs, females). Ixodes hexagonus accounted for 73% and I. ricinus for 27% of the collected ticks. Male hedgehogs carried significantly higher tick burdens than females. Analyses of seasonal prevalence and abundance of I. hexagonus revealed relatively stable levels of infestation of all parasitic stages, with a modest summer peak in tick abundance noted only on male hosts. By contrast, I. ricinus females and nymphs peaked in spring and declined steadily thereafter in summer and autumn, whereas the less abundant larvae peaked in summer. This is the first longterm study to evaluate the seasonal dynamics of both tick species on populations of wild hedgehogs inhabiting urban residential areas.     

Analyzing notochord segmentation and intervertebral disc formation using the twhh:gfp transgenic zebrafish model

To characterize the process of vertebral segmentation and disc formation in living animals, we analyzed tiggy-winkle hedgehog (twhh):green fluorescent protein (gfp) and sonic hedgehog (shh):gfp transgenic zebrafish models that display notochord-specific GFP expression. We found that they showed distinct patterns of expression in the intervertebral discs of late stage fish larvae and adult zebrafish. A segmented pattern of GFP expression was detected in the intervertebral disc of twhh:gfp transgenic fish. In contrast, little GFP expression was found in the intervertebral disc of shh:gfp transgenic fish. Treating twhh:gfp transgenic zebrafish larvae with exogenous retinoic acid (RA), a teratogenic factor on normal development, resulted in disruption of notochord segmentation and formation of oversized vertebrae. Histological analysis revealed that the oversized vertebrae are likely due to vertebral fusion. These studies demonstrate that the twhh:gfp transgenic zebrafish is a useful model for studying vertebral segmentation and disc formation, and moreover, that RA signaling may play a role in this process.     

Factors affecting hedgehog presence on farmland as assessed by a questionnaire survey

The West European hedgehog, (Erinaceus europaeus, Linnaeus 1758) is widely distributed in Western Europe. However, there is evidence of decline in parts of its range. Changes in agricultural management have partly been the driving force behind the loss of species diversity and abundance, and it has been argued that these changes play a role in the decline of hedgehogs as well. We used a questionnaire to investigate the current distribution of hedgehogs on farmland throughout Great Britain with a focus on different environmental zones. Additionally, we identified environmental correlates that related to the distribution of hedgehogs with the aim to get a better understanding of what is needed to design appropriate strategies targeted at the conservation of hedgehogs. Our study illustrates that, although the impact of several variables was rather ambiguous, displaying positive effects in some environmental zones and negative effects in other, major roads and Eurasian badgers (Meles meles, Linnaeus 1758) can have large scale negative effects on hedgehogs. Farm management related factors did not show a consistent impact on hedgehog presence. Conservation strategies should therefore be aimed at lessening the impacts of major roads and badger presence. Wildlife passages, for instance, may provide hedgehogs safe passages across roads. Additionally, increasing the habitat complexity in order to reduce the impact of predators can be beneficial for prey species, such as hedgehogs, and should be considered as a conservation strategy for them.     

Ultrastructure and lipid chemistry of specialized epidermal structure of Indian porcupines and hedgehog

Poddar‐Sarkar, M., Raha, P., Bhar, R., Chakraborty, A. and Brahmachary, R.L. 2011. Ultrastructure and lipid chemistry of specialized epidermal structure of Indian porcupines and hedgehog. —Acta Zoologica (Stockholm) 92 : 134–140. In the present study, we investigated the ultrastructural variations of specialized epidermal structure of Indian porcupines (Hystrix indica and Atherurus macrourus) and hedgehog (Hemiechinus collaris) as well as the variation in the fatty acid composition of total lipid fraction. Scanning electron microscope images reveal the usual scaly structure in surface view and network of channels in cross‐section but with different orientation of partition walls. The lipid profile reveals the presence of free sterol, long‐chain alcohol, free fatty acids, wax ester and sterol ester in all the three cases and trace amount of triglyceride, diglyceride and monoglyceride. Gas chromatography–mass spectrometry analysis of fatty acid methyl ester of total lipid fraction indicates the presence of C₈‐C₂₂ fatty acids in Hystrix indica, C₈‐C₁₈ in Atherurus macrourus and C₈‐C₂₀ fatty acids in Hemiechinus collaris. It is interesting to note that the total lipid fraction of hedgehog shows no branched‐chain, unsaturated and odd‐carbon fatty acids. Odd‐carbon fatty acid and branched‐chain fatty acids detected in the adult H. indica but were absent in juvenile H. indica as well as in A. macrourus. With the exception of C_18:1, the other unsaturated fatty acids were also absent in both juvenile H. indica and A. macrourus.     

Giant sex chromosomes retained within the Portuguese lineage of the field vole (<Emphasis Type="Italic">Microtus agrestis</Emphasis>)

The field vole (Microtus agrestis) is characterised by extremely large blocks of heterochromatin on both the X and Y chromosome. Some other Microtus also have blocks of heterochromatin on their sex chromosomes but not as extensive and always of independent origin from the heterochromatic expansion found in M. agrestis. Coupled with evidence of geographic variation in large heterochromatic blocks within other species (e.g. in the western hedgehog Erinaceus europaeus), it might be expected that field voles would show substantial variation in size and disposition of the sex chromosome heterochromatin. In fact, only minor variation has been described up to now. Those studies conducted previously were largely on field voles from central and northern Europe. Here, we describe the karyotype of field voles from Portugal, of interest because recent molecular studies have shown field voles from western Iberia to be a separate evolutionary unit that might be considered a cryptic species, distinct from populations further to the east. The two Portuguese field voles (one female, one male) that we examined also had essentially the same karyotype as seen in other field voles, including the giant sex chromosomes, but with small differences in the structure of the Y chromosome from that described previously. The finding that field voles throughout Europe show relatively little variation in their giant sex chromosomes is consistent with molecular data which suggest a recent origin for this complex of species/near-species.     

Early developmentally regulated genes in the arbuscular mycorrhizal fungus Glomus mosseae: identification of GmGIN1, a novel gene with homology to the C-terminus of metazoan hedgehog proteins

The life cycle of the obligate biotrophic arbuscular mycorrhizal fungi comprises several well-defined developmental stages whose genetic determinants are still unknown. With the aim of understanding the molecular processes governing the early developmental phase of the AM fungal life cycle, a subtractive cDNA library was constructed using a suppressive subtractive hybridization technique. The library contains more than 600 clones with an average size of 500 bp. The isolated cDNAs correspond to genes up-regulated during the early development of the AM fungus Glomus mosseaeversus genes expressed in extraradical hyphae. The expression of several of the isolated genes was further confirmed by RT-PCR analysis. Among the isolated clones, a novel gene named GmGIN1 only expressed during early development in G. mosseae was found. The full-length GmGIN1 cDNA codes for a protein of 429 amino acids. The most interesting feature of the deduced protein is its two-domain structure with a putative self-splicing activity. The N-terminal domain shares sequence similarity with a novel family of GTP binding proteins while the C-terminus has a striking homology to the C-terminal part of the hedgehog protein family from metazoa. The C-terminal part of hedgehog proteins is known to participate in the covalent modification of the N-terminus by cholesterol, and in the self-splicing activity which renders the active form of the protein with signalling function. We speculate that the N-terminal part of GmGIN1, activated through a similar mechanism to the hedgehog proteins, has GTP-binding activity and participates in the signalling events prior to symbiosis formation.     

<Emphasis Type="Italic">Trichophyton erinacei</Emphasis> Infection from a Hedgehog: A Case Report from Taiwan

Trichophyton erinacei is a fungus affecting hedgehogs. As these animals have become popular as exotic pets, human infections with this organism have been documented in many countries. In Taiwan, a 36-year-old woman developed tinea lesions at multiple sites after carrying a sick hedgehog. The animal subsequently lost its quills and died. On culture of the patient’s skin scrapings, the pathogen was identified mycologically as Trichophyton erinacei, which was confirmed by sequencing of the internal transcribed spacers of the fungal nuclear ribosomal DNA. The same fungus was isolated from the sawdust bed previously used by the diseased hedgehog. A careful contact history is important for identifying this emerging zoonosis.     

Phylogenetic position of the Tenrecs (Mammalia: Tenrecidae) of Madagascar based on analysis of the complete mitochondrial genome sequence of Echinops telfairi

The phylogenetic position of the lesser hedgehog tenrec, Echinops telfairi, was studied on the basis of analysis of the concatenated sequences of 12 mitochondrial protein‐coding genes. In addition to the tenrec, the analysis included two other representatives of the insectivore order Lipotyphla, the hedgehog and the mole. The eutherian tree was rooted with three non‐eutherian mammalian taxa. The analysis joined the tenrec, the African elephant (order Proboscidea) and the aardvark (order Tubulidentata) on a common branch. The three lipotyphlan taxa, the tenrec (Tenrecidae), the mole (Talpidae) and the hedgehog (Erinaceidae) were dispersed in the eutherian tree, demonstrating lipotyphlan polyphyly.