Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “INSECTIVORA”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed2003

Giant mitochondria in the retina cone inner segments of shrews of genus Sorex (Insectivora, Soricidae).

The retinas of three species of shrews (Sorex araneus, S. coronatus, and S. minutus) were analyzed. Two kinds of photoreceptors were identified according to (among other characteristics) the traits of the mitochondria of their inner segments. The rod inner segments contained several round or oval mitochondria distributed longitudinally inside the ellipsoid. The cone inner segment showed a few mitochondria, which we classified as megamitochondria (maximum length = 4.22 microm in S. araneus, 5.68 microm in S. coronatus, and 2.42 microm in S. minutus). An analysis of serial thin sections in S. coronatus showed that these large organelles occurred in the apical and central portions of the ellipsoid. In the peripheral and basal regions of the ellipsoid, megamitochondria were frequently accompanied by smaller mitochondria. The giant mitochondria were irregular in form and densely packed, and a reduced cytosol was observed between each mitochondria. In general, they exhibited an electron-dense matrix and a complex system of cristae, which varied in length and array. In mammalian retina, megamitochondria have only been described in the ellipsoid of the tree shrews Tupaia glis and T. belangeri, two diurnal Scandentia with a rich-cone retina. In general terms, Sorex megamitochondria are morphologically very similar to those reported for Tupaia, especially in their arrangement in the cone ellipsoid. However, they differ in the orientation of the cristae. We propose that the ellipsoid of Sorex may serve two functions: as a source of energy for receptor cells, and as a device for improving the cone outer segment optics.

Animals↗
PubMed1992

The ear in subterranean insectivora and rodentia in comparison with ground-dwelling representatives. I. Sound conducting system of the middle ear.

Compared to acoustically unspecialized mammals (soricids and murids), the middle ear of subterranean insectivores and rodents (twelve species of six families examined) was clearly distinguished and characterized by many common features: rather round and relatively larger eardrum without a pars flaccida; reduced gonial; loose or no connection between the malleus and the tympanic bone; reduced and straightened transversal part of the malleus; enlarged incus; increased and rather flat incudo-mallear joint; rather parallel position of the mallear manubrium and incudal crus longum in some species (and their fusion in bathyergids); reduced or even missing middle ear muscles. Convergent occurrence of these structural features in taxa of different origin and their generally derived character suggest that they cannot be categorized as degenerative. The form of the stapes can be considered as a non-adaptive trait; it was taxon specific yet remarkably polymorphous in some species and exhibited no convergent features among subterranean mammals. Structural retrogression resulting in a columella-like stapes was observed in some species lacking the stapedial artery. The stapedial base was relatively larger than in unspecialized mammals. The subterranean mammals did not exhibit conspicuously enlarged eardrums as would be required for sensitive tuning to low frequencies. It is, however, argued that while selective pressures in the subterranean ecotope promoted hearing of low frequencies, hearing sensitivity did not have to be enhanced.

Animals↗
PubMed1994

Evolution of mtDNA D-loop sequences and their use in phylogenetic studies of shrews in the subgenus Otisorex (Sorex: Soricidae: Insectivora).

mtDNA D-loop sequences were examined in shrews of the genus Sorex. All specimens possessed an array of tandem repeats in which each repeat was 78 to 80 base pairs (bp) in length. Each specimen also possessed a 76-bp imperfect copy of the tandem repeats. Three observations are consistent with the tandem repeats being the product of concerted evolution: (1) the repeats are capable of forming secondary structures; (2) there was minimal sequence divergence between tandem repeats within individuals; and (3) although the tandem repeats and the imperfect repeat presumably arose due to a duplication event in an ancestor of the shrews, the imperfect repeat per se was not copied in any of the specimens observed. Interspecific homology can therefore be assumed for the imperfect repeat. Furthermore, given the apparent high rate of concerted evolution within a genome, tandem repeats in different individuals may be compared as though only a single copy were present. By including data from the imperfect repeat, the last tandem repeat, and the surrounding unique sequence cladistic and genetic distance approaches to phylogeny reconstruction indicated two sister groups within the subgenus Otisorex. One group was composed of Sorex fumeus and the S. cinereus species complex and the other group was composed of S. hoyi, S. monticolus, S. vagrans, and S. palustris. Resolution of relationships among recently evolved taxa demonstrated the usefulness of selected regions of the D-loop for molecular systematic studies.

Animals↗
PubMed1999

Molecular phylogeny and evolution of Sorex shrews (Soricidae: insectivora) inferred from mitochondrial DNA sequence data.

Shrews of the genus Sorex are characterized by a Holarctic distribution, and relationships among extant taxa have never been fully resolved. Phylogenies have been proposed based on morphological, karyological, and biochemical comparisons, but these analyses often produced controversial and contradictory results. Phylogenetic analyses of partial mitochondrial cytochrome b gene sequences (1011 bp) were used to examine the relationships among 27 Sorex species. The molecular data suggest that Sorex comprises two major monophyletic lineages, one restricted mostly to the New World and one with a primarily Palearctic distribution. Furthermore, several sister-species relationships are revealed by the analysis. Based on the split between the Soricinae and Crocidurinae subfamilies, we used a 95% confidence interval for both the calibration of a molecular clock and the subsequent calculation of major diversification events within the genus Sorex. Our analysis does not support an unambiguous acceleration of the molecular clock in shrews, the estimated rate being similar to other estimates of mammalian mitochondrial clocks. In addition, the data presented here indicate that estimates from the fossil record greatly underestimate divergence dates among Sorex taxa.

Animals↗
PubMed2002

Molecular phylogeny of short-tailed shrews, Blarina (Insectivora: Soricidae).

Phylogenetic relationships among the three described species of short-tailed shrews (genus Blarina) were inferred based on mitochondrial DNA sequences of 16S rRNA (506 bp) and cytochrome b (1137 bp) from 38 specimens representing B. brevicauda, B. hylophaga, and B. carolinensis, from across their range in North America. Phylogenetic analyses of both data sets combined followed tests showing lack of incongruence between these fragments. Analysis of substitution patterns indicated saturation of transitions at third codon positions in cytochrome b when Blarina sequences were compared to those of Sorex and Cryptotis, used as outgroups. Maximum-likelihood and weighted parsimony supported the monophyly of the genus and placed B. hylophaga as its basal branch, sister to B. brevicauda + B. carolinensis. Phylogeographic analysis revealed a significant partition between eastern and western populations of B. carolinensis and B. brevicauda, on either side of the Mississippi basin. These results are discussed in relation to cytogenetic, morphological, and fossil data.

Animals↗
PubMed1991

The karyotype of the middle-African hedgehog Atelerix albiventris Wagner, 1841 and its cytotaxonomical relationships to other Erinaceinae (Insectivora: Erinaceidae).

Like other hedgehog species investigated hitherto, also the Middle African species Atelerix albiventris has a diploid number of 48 chromosomes. However, Aethechinus and Atelerix display quite distinct cytogenetic characteristics compared to the hedgehog genera Erinaceus, Hemiechinus and Paraechinus. Individual chromosome structures and reactivities permit the recognition of similarities to the Algerian hedgehog Aethechinus algirus and indicate their close relationship. Nevertheless, the proposal by Corbet (1988) to merge the two taxa into one genus, which is contrary to Robbins and Setzer (1985) remains to be clarified by further investigations.

Animals↗
PubMed1978

Apical protuberances of supporting cells in the regio olfactoria of the mole, Talpa europaea, Linnaeus, 1758 (Insectivora, Talpidae).

The regio olfactoria of the mole, Talpa europaea, was studied by scanning and transmission electron microscopy. Peculiar structural differentiations, i.e. ovoid-shaped, balloon-like protuberances were found on the surface of the supporting cells. The apical portion of these protuberances contained finely dispersed granular material, whereas in their central part vesicular extensions of the smooth endoplasmic reticulum were observed.

Animals↗
PubMed1995

Gene mapping in the common shrew (Sorex araneus; Insectivora) by shrew-rodent cell hybrids: chromosome localization of the loci for HPRT, TK, LDHA, MDH1, G6PD, PGD, and ADA.

We selected the common shrew (Sorex araneus) to generate the first insectivore gene map. Shrew-Chinese hamster and shrew- mouse somatic cell hybrid cells were constructed. When the 119 shrew-rodent clones were characterized, only shrew chromosomes were found to have segregated. A panel of hybrid clones was selected for gene assignment. The genes for hypoxanthine phosphoribosyl transferase (HPRT), glucose-6- phosphate dehydrogenase (G6PD), and malate dehydrogenase 1 (MDH1) were assigned to shrew Chromosome (Chr) de [which is the product of a tandem fusion between the 'original' mammalian X Chromosome (Chr) and an autosome], the gene for adenosine deaminase (ADA) and 6-phosphogluconate dehydrogenase se (PGD) to Chromosome jl, the gene for thymidine kinase (TK) to Chromosome hn, and the gene for lactate dehydrogenase (LDHA) to chromosome ik. Further studies in progress.

Adenosine Deaminase↗
PubMed1987

Genetic differentiation between laboratory lines of the musk shrew (Suncus murinus, Insectivora) based on restriction endonuclease cleavage patterns of mitochondrial DNA.

The cleavage patterns of mitochondrial DNA (mtDNA) by 17 restriction endonucleases were compared between eight lines of musk shrews derived from different wild-caught stocks. Enzymatic digestion by BamHI, PvuII, XbaI, and XhoI showed a cleavage pattern common to all lines that were from five Japanese islands (Nag, Ize, OKI, TKU, and Tr), Bangladesh (BAN), Sri Lanka (SRI), and Java (Bog), and every line lacked cleavage sites for SalI and SmaI. Different cleavage patterns were detected by the remaining 11 enzymes. Within the BAN line, the presence of at least two types of mtDNAs was proved by six enzymes and was not contradictory to the maternal pedigrees going up to the wild ancestors of the stock. More than 30 cleavage sites of the shrew mtDNA were mapped by double-digestion methods. Nucleotide diversities of mtDNA were calculated from these maps and were estimated to be less than 0.5% among Japanese and Bog lines but to be 3.8% between BAN and the other seven lines and 2.3% within the BAN line. These results indicate that BAN shrews differentiate from the other lines to the intersubspecific extent reported in mice previously.

Animals↗
PubMed1990

Genetic relationship among the musk shrews, Suncus murinus Insectivora, inhabiting islands and the continent based on mitochondrial DNA types.

Cleavage patterns of mitochondrial DNA (mtDNA) by restriction endonucleases were examined in musk shrews collected at six trapping sites on two Japanese and two Indonesian islands, on Sri Lanka, situated close to the Indian subcontinent, and on the mainland of East Bengal in Bangladesh. No variation of mtDNAs was found among the Japanese and Indonesian shrews, despite their geographical isolation by the sera. In contrast, at least six mtDNA types were present in the Sri Lanka and the Bangladesh populations (three types for each), and these two populations seemed to be differentiated to the extent, which could be compared to the "mice-intersubspecific" differences. These populations were also differentiated from the Japanese-Indonesian type. Furthermore, a similar level of differentiation was also estimated between two mtDNA types within these respective populations. This feral species might be considered unique because of its high emigration rate caused by human movements and its high rate of subspecific hybridization.

Animals↗
PubMed1993

Esophageal carcinoma in house musk shrews, Suncus murinus (Insectivora), induced by N-methyl-N'-nitro-N-nitrosoguanidine.

Female 6-week-old shrews were given a solution of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) at a concentration of 50 micrograms/ml or 100 micrograms/ml in the drinking water. All 11 shrews receiving 100 micrograms/ml MNNG died 8-13 days after the beginning of carcinogen administration and 6 of the 20 shrews receiving 50 micrograms/ml MNNG died after 10-54 days. When animals were between 43 and 54 weeks of age, multiple esophageal lesions were evoked in all 14 that had received 50 micrograms/ml MNNG for 30 weeks. All shrews developed a protruding, ulcerative, or superficial type of squamous-cell carcinoma of the esophagus, accompanied by papillomas. Local invasion was seen in squamous-cell carcinoma but no distant metastasis was noted. None of the 5 control shrews developed any esophageal abnormality. No gastric adenocarcinoma, intestinal sarcoma, or other tumors were induced with MNNG. It can be concluded that MNNG has a carcinogenic effect on shrew esophageal epithelium.

Animals↗
PubMed1990

Hantavirus strains isolated from rodentia and insectivora in rural China differentiated by polymerase chain reaction assay.

Polymerase chain reaction (PCR) assay and other techniques were applied to differentiate Hantavirus strains isolated from different animal hosts and geographic regions in China. Two groups of related strains, Hantaan and Seoul, have been classified by cross-neutralization, radioimmunoprecipitation (RIP), and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) assays. The molecular weights of glycoprotein 1 (G1) of Hantaan and Seoul viruses were 72k and 80k, whereas those of the nucleocapsid (N) and glycoprotein 2 (G2) remained the same, respectively. The PCR assay was used to differentiate these isolates using synthetic oligonucleotide primers selected from various regions of the M genome of 76118 and R22 strains. 76118-specific primers amplified only the RNAs extracted from Hantaan strains while R22-specific primers, the RNAs from Seoul strains. The PCR results for classification are consistent with those obtained by cross-neutralization, RIP and SDS-PAGE assays.

Animals↗
PubMed2002

The helminth community of Talpa romana (Thomas, 1902) (Insectivora, Talpidae) in southern Italy.

The helminth parasite community of Talpa romana in Calabria (southern Italy ) was studied. The helminth fauna comprised six species: Ityogonimus ocreatus (Goeze 1782), Staphylocistis bacillaris (Goeze 1782), Capillaria talpae (Siebold 1850), Parastrongyloides winchesi (Morgan 1928), Spirura talpae (Gmelin 1790), and Tricholinstowia linstowi (Travassos 1918). All species except S. bacillaris were dominant in this community. The helminths are all stenoxenous species of Paleartic Talpaspp. This paper is the first quantitative approach to the helminth community of T. romana and reveals typical characteristics of an isolationist community. This can be explained by genetic and paleogeographic events.

Animals↗