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At least 289 records · Page 16Linked to original sources

Natural vectors of three bovine Onchocerca species (Nematoda: Onchocercidae) and seasonal transmission by three blackfly species (Diptera: Simuliidae) in central Kyushu, Japan.

Eleven blackfly species were examined in relation to the transmission of bovine onchocerciasis in central Kyushu, Japan. A total of 19,005 out of 47,746 females captured from June 1989 to June 1990 at two cattle sheds each in Oita and Kumamoto were dissected for their parities, infections with Onchocerca larvae, and intakes of Onchocerca microfilariae. Overall results showed that Simulium bidentatum (Shiraki), the predominant species, is a natural vector of the two bovine Onchocerca species, i.e., type I (O. sp.) in both localities and type II (probably O. gutturosa Neumann), in Oita, whereas S. kyushuense Takaoka and S. arakawae Matsumura serve as the primary vector of type III (O. lienalis Stiles) in Kumamoto and Oita, respectively. Simulium arakawae also plays a secondary role in the transmission of type I in Oita and of type III in Kumamoto. Despite the biting activities and microfilarial intakes observed throughout most of the entire year, the transmission of these bovine Onchocerca was restricted to the mild or warm months between May and November. The natural infections with mermithid, trematode, ciliates, and fungi occurred but their influence on the vector Simulium species was apparently small, if at all.

Animals↗

Studies of sibling Drosophila species from Laguna Verde, Veracruz, Mexico: I. Species frequencies, viability, desiccation resistance, and vagility.

The sibling species Drosophila melanogaster and D. simulans were collected at Laguna Verde, Veracruz, Mexico. D. melanogaster was found in significantly greater frequency than was D. simulans. Ten isofemale lines of each species were tested for egg to adult viability, desiccation resistance, and vagility. D. melanogaster surpassed D. simulans in all three characteristics. The findings are discussed with reference to the climatic conditions at Laguna Verde and the expected effect of such an environment on the relative frequencies of these species. The dichotomous results in regard to desiccation resistance and vagility that were observed between recently collected D. melanogaster and the Oregon-R laboratory stock of that species are also discussed.

Animals↗

Are most species small? Not within species-level phylogenies.

The robust macro-ecological observation that there are more small-bodied species implies that small-bodied organisms have experienced elevated net rates of diversification. We investigate the role of body size in creating non-random differences in rates of cladogenesis using a set of 38 species-level phylogenies drawn from a range of animal groups. We use independent contrasts to explore the relationship between body size and species richness within individual phylogenies and across related sets of phylogenies. We also carry out a meta-analysis looking for associations between body size and species richness across the taxa. We find little evidence for increased cladogenesis among small-bodied organisms within taxa, and no evidence for any consistent differences between taxa. We explore possible explanations for the inconsistency of our findings with macro-ecological patterns.

Animals↗

A new approach to use of bacteriolytic enzymes as a tool for species identification: selection of species-specific indicator strains with bacteriolytic activity towards Enterococcus strains.

We describe the bacteriolytic activity of 377 group D Enterococcus isolates expressed towards 25 Enterococcus strains belonging to different species and Micrococcus luteus ATCC 4698. Of the 26 indicator strains used to reveal bacteriolytic activity, 5 were lysed by all of the strains of some species and were not lysed by all of the strains of other species. The use of these indicator strains allowed us to devise a new method to differentiate group D Enterococcus strains, based on qualitative analysis (lysis or no lysis of the indicator strains) of bacteriolytic activity. The bacteriolytic patterns obtained fell into six bacteriolytic groups corresponding (98% agreement) to species or groups of enterococci as determined by a comparison with data from a phenetic similarity study.

Bacterial Typing Techniques↗

Arabidopsis species hybrids in the study of species differences and evolution of amphiploidy in plants.

It is estimated that 5 million years of evolution separate Arabidopsis thaliana from its close relative Arabidopsis lyrata. The two taxa differ by many characteristics, and together they exemplify the differentiation of angiosperms into self-fertilizing and cross-fertilizing species as well as annual and perennial species. Despite their disparate life histories, the two species can be crossed to produce viable and vigorous hybrids exhibiting heterotic effects. Although pollen sterile, the hybrids produce viable ovules and were used as female parent in backcrosses to both parental species. The resulting backcross plants exhibited transgressive variation for a number of interesting developmental and growth traits as well as negative nuclear/cytoplasmic interactions. Moreover, the genesis of a fertile amphidiploid neospecies, apparently by spontaneous somatic doubling in an interspecific hybrid, was observed in the laboratory. The mechanisms responsible for the generation of amphiploids and the subsequent evolution of amphiploid genomes can now be studied through direct observation using the large arsenal of molecular tools available for Arabidopsis.

Arabidopsis↗

Aspects of species recognition by sound in four species of damselfishes, genus Eupomacentrus (Pisces: Pomacentridae).

Members of four sympatric species of Eupomacentrus carry out reproductive activities at the same time of the year and produce similar pulsed courtship sounds. Such sounds are known to facilitate courtship among conspecifics. Consequently, members of the four species in the field and in the laboratory were tested with the various sounds to determine if they could distinguish their own species sounds from those produced by congeners. The differential responses clearly demonstrate species specific recognition by sound and indicate that the pulse interval and the number of pulses per sound are the important parameters for this recognition.

Animals↗

Distribution of baboon endogenous virus among species of African monkeys suggests multiple ancient cross-species transmissions in shared habitats.

PCR amplification of baboon endogenous virus (BaEV) long terminal repeat, reverse transcriptase gene, and env fragments from 24 different species of African monkeys indicates that BaEV is less widespread than was formerly thought. Instead of being present in every species of African primates, BaEV can be found only in baboons, geladas, and mangabeys (all belonging to the Papionini tribe) and in African green monkey (Cercopithecus aethiops)subspecies. BaEV, which can be activated from baboon and gelada tissues, was most likely introduced in the germ line only recently (less than a few million years ago) and has not been inherited from a common ancestor of all extant African monkeys. Neighbor-joining and maximum-likelihood analyses of the sequences obtained showed that two distinct virus clusters can be distinguished: the first containing baboon, gelada, and African green monkey BaEV sequences and the second consisting of mandrill and mangabey BaEV sequences. This viral evolutionary tree does not follow host phylogeny, indicating the cross-species transmissions and multiple germ line fixations of the virus must have occurred in the past. BaEV sequences are found in monkeys inhabiting savannas (baboons, geladas, and African green monkeys) as well as forests (managabeys and mandrills) and cluster according to the habitats of their hosts, providing evidence for cross-species transmission in shared habitats.

Amino Acid Sequence↗

Species-specific TT viruses and cross-species infection in nonhuman primates.

Viruses resembling human TT virus (TTV) were searched for in sera from nonhuman primates by PCR with primers deduced from well-conserved areas in the untranslated region. TTV DNA was detected in 102 (98%) of 104 chimpanzees, 9 (90%) of 10 Japanese macaques, 4 (100%) of 4 red-bellied tamarins, 5 (83%) of 6 cotton-top tamarins, and 5 (100%) of 5 douroucoulis tested. Analysis of the amplification products of 90 to 106 nucleotides revealed TTV DNA sequences specific for each species, with a decreasing similarity to human TTV in the order of chimpanzee, Japanese macaque, and tamarin/douroucouli TTVs. Full-length viral sequences were amplified by PCR with inverted nested primers deduced from the untranslated region of TTV DNA from each species. All animal TTVs were found to be circular with a genomic length at 3.5 to 3.8 kb, which was comparable to or slightly shorter than human TTV. Sequences closely similar to human TTV were determined by PCR with primers deduced from a coding region (N22 region) and were detected in 49 (47%) of the 104 chimpanzees; they were not found in any animals of the other species. Sequence analysis of the N22 region (222 to 225 nucleotides) of chimpanzee TTV DNAs disclosed four genetic groups that differed by 36.1 to 50.2% from one another; they were 35.0 to 52.8% divergent from any of the 16 genotypes of human TTV. Of the 104 chimpanzees, only 1 was viremic with human TTV of genotype 1a. It was among the 53 chimpanzees which had been used in transmission experiments with human hepatitis viruses. Antibody to TTV of genotype 1a was detected significantly more frequently in the chimpanzees that had been used in transmission experiments than in those that had not (8 of 28 [29%] and 3 of 35 [9%], respectively; P = 0.038). These results indicate that species-specific TTVs are prevalent in nonhuman primates and that human TTV can cross-infect chimpanzees.

Animals↗

Levels of small molecules in dormant spores of Sporosarcina species and comparison with levels in spores of Bacillus and Clostridium species.

Dormant spores of Sporosarcina halophila and Sporosarcina ureae contained no detectable ATP, significant levels of ADP, even higher levels of AMP, and a large pool of 3-phosphoglyceric acid, similar to what is found in dormant spores of Bacillus and Clostridium species. Sporosarcina halophila and S. ureae spores also contained significant pools of free amino acids, in particular glutamic acid, as in the case with spores of Bacillus but not Clostridium species. Levels of monovalent and divalent inorganic cations were comparable in spores of Sporosarcina, Clostridium, and Bacillus species, and cation levels in spores of the slight halophile S. halophila were similar to those in S. ureae spores. These data suggest that levels of small molecules are generally similar in spores of all Gram-positive organisms, and further suggest that these levels reflect fundamental and conserved features of the sporulation process and dormant spores in these organisms. The data are also consistent with the proposed close evolutionary relationship between Bacillus and Sporosarcina species.

Adenine Nucleotides↗

Capacity for red blood cell aggregation is higher in athletic mammalian species than in sedentary species.

The purpose of this study was to show that two rheological parameters, red blood cell (RBC) sedimentation rate and apparent blood viscosity at low shear rate, characterizing the degree of RBC aggregation, correlate significantly with the maximal mass-specific rate of oxygen consumption or aerobic capacity (VO2max). Comparisons were made within two groups of similarly sized athletic and sedentary species: group 1, pronghorn antelope, dog, goat, and sheep; and group 2, horse and cow. The pronghorn antelope (Antilocapra americana) is one of the most athletic mammals, and we have obtained data on the rheological properties of blood from this species for the first time. The values of apparent viscosity at hematocrit = 40% and shear rate = 0.277 s-1 measured in a rotational viscometer were 59.5, 42.6, and 9.1 cP for antelope, dog, and sheep blood, respectively, and 55.3 and 11.5 cP for horse and cow blood, respectively. The viscosity values for antelope, dog, and sheep blood can be correlated with aerobic capacity: ln viscosity = 4.48-106.3 VO2(-1)max (r2 = 0.998; P < 0.05). The values of RBC sedimentation rate at hematocrit = 40% were 12.8, 7.0, and 0 mm/h for antelope, dog, and sheep blood, respectively, and 45.3 and 0.1 mm/h for horse and cow blood, respectively. Therefore, the data showed that the athletic species exhibit a consistently higher degree of RBC aggregation than do the corresponding nonathletic species.

Animals↗

Comparative analysis of karyotypes in European shrew species. I. The sibling species Sorex araneus and S. gemellus: Q-bands, G-bands, and position of NORs.

The karyotypes of two closely related species of the genus Sorex (Mammalia, Insectivora) were compared with each other by G- and Q-banding techniques and by Ag-AS staining (GOODPASTURE and BLOOM, 1975). By comparing the G-banded karyotypes, it could be ascertained that the basic differences in karyotype between the two species lie in three pericentric inversions, three paracentric inversions, and one reciprocal translocation. This is in near agreement with FORD and HAMERTON (1970), who assumed that both species differ by three pericentric inversions and one tandem translocation. Furthermore, the karyotype of S. araneus (race C) presented by HALKKA et al. (1974) has been compared with the S. araneus of the present report. Considering the species with respect to karyotypic evolution, it is supposed that S. araneus and S. gemellus derive from a common ancestor.

Animals↗

Selection and characterization of monoclonal antibodies against a major allergen in Dermatophagoides pteronyssinus. Species-specific and common epitopes in three dermatophagoides species.

Hybridomas were produced after immunization with Der p I (Ag 42, P1). Specific anti-Der p I activity was detected in a reverse ELISA using immobilized anti-mouse Ig and highly purified Der p I labelled with horseradish peroxidase. Stable subclones from 6 parental hybridomas were obtained. The species specificities of the monoclonal antibodies (MABs) were classified: by an overlayer technique analogous to the CRIE technique, and by two competitive ELISA techniques. One MAB recognized an epitope specific for Dermatophagoides pteronyssinus. This MAB was successfully employed as a coating reagent in a species-specific ELISA for Der p I in house dust. The remaining antibodies reacted with epitopes shared to varying degrees by either of two other Dermatophagoides species. MABs recognizing epitopes common to all 3 species were not observed. Mutual cross-inhibition studies revealed four topographically distinct antibody binding sites on Der p I.

Allergens↗

Distinctive responses in the medial amygdala to same-species and different-species pheromones.

Chemosignals related to reproductive and social status (pheromones) carry messages between opposite-sex and same-sex individuals in many species. Each individual must distinguish signals relevant to its own social behavior with conspecifics from signals used by other (heterospecific) species relevant to their social behavior. In male hamsters, the medial amygdala responded in a categorically different way to conspecific stimuli (socially relevant) and heterospecific stimuli (not socially relevant but serving similar purposes for other species), and may play an important role in this decision. Immediate-early gene responses to conspecific chemosignals and heterospecific chemosignals were characteristically different. The categorical responses, generated by chemosensory input from the vomeronasal organ and (probably) GABA inhibition within the amygdala, were not apparent at more peripheral sensory levels. This is the first evidence for an important role of the amygdala, a limbic structure known to be involved in social and emotional behavior, in discrimination of species specificity in chemosignals.

Administration, Intranasal↗

Genetic relationships among Korean brown frog species (Anura, Ranidae), with special reference to evolutionary divergences between two allied species Rana dybowskii and R. huanrenensis.

Allozyme analysis for 41 populations of brown frog species, Rana dybowskii, R. huanrenensis, and R. amurensis from Korea and three reference species (Chinese R. chensinensis and Japanese R. dybowskii and R. tsushimensis), were performed to clarify taxonomic status of Korean brown frogs. The level of average genetic differentiation (Nei's D) among local populations of each species in Korea was very low (D<0.01 2) and Korean and Japanese R. dybowskii also showed conspecific level of differentiation (D=0.070). Whereas, much larger, discrete genetic differences were detected in the interspecific comparisons (D>0.370). In the genetic relationships among five species examined, the 24 chromosome brown frogs (R. dybowskii, R. huanrenensis, and R. chensinensis) did not form a monophyletic group. Rana dybowskii with the chromosome number of 2n=24 was grouped together with R. amurensis with the chromosome number of 2n=26. The hypothesis of reversal change from 24 to 26 in Korean R. amurensis seems to better explain the phylogenetic relationships of east Asian brown frogs than the assumption of parallel reduction in chromosome number from 2n=26 to 24 in R. dybowskii and in the common ancestor of R. huanrenensis and R. chensinensis. The genetic, morphological, and reproductive divergences between Korean R. dybowskii and R. huanrenensis were compared.

Animals↗

A new species group in the genus Dichaetophora Duda (Diptera: Drosophilidae) based on a phylogenetic analysis, with descriptions of four new species from China.

A new species group, the sinensis group, is established within the genus Dichaetophora, based on a phylogenetic analysis of 37 adult morphological characters from 26 drosophilid species, including ten known species of Dichaetophora; four newly described species (Di. abnormis, Di. hainanensis, Di. bicornis, and Di. sinensis spp. nov. from China); and some representatives of related genera (Drosophila, Hirtodrosophila, and Scaptomyza).

Animal Structures↗

Species- and sex-related differences in the plasma clearance and metabolite formation of antipyrine. A comparative study in four animal species: cattle, goat, rat and rabbit.

1. The plasma disposition of antipyrine, and its urinary metabolite pattern, were studied in both sexes of four animal species: rat, dwarf goat, rabbit and cattle. 2. No sex differences in plasma elimination of antipyrine were found in rabbit and goat; however, in rat and cattle the effect of sex was marked. As expected, male rat showed a higher plasma clearance value than female. In contrast bulls showed a significantly lower clearance value than cows. 3. Metabolite patterns varied widely from one species to another. The major urinary metabolite in rabbit and the two ruminant species was 4-hydroxy-antipyrine (OHA), whereas in rat 3-hydroxymethylantipyrine (HMA) was quantitatively the most important metabolite. 4. HMA was excreted in the 24 h urine in larger amounts by male rats than by females. Metabolism of antipyrine to HMA was also sexually different in the dwarf goat, but in this species females were more active than males. The effect of sex on the metabolite pattern in cattle was marked. 5. It is concluded that in ruminants there may be xenobiotic metabolic pathways which are under hormonal control, just as there are in rats and mice. If hormones influence drug metabolism in food-producing animals, residue levels of xenobiotics or their metabolites in food from animal origin may differ with the sex of the animal, or may be altered after treatment with anabolic hormones.

Animals↗

[The correlation variability of the morphometric traits in 4 species of ixodid tick species (Ixodidae)].

Correlation analysis of 10 characters was run in three species of Dermacentor, D. nuttalli, D. ushakovae, D. niveus, and in Ixodes persulcatus, separately for each phase and sex. Correlation coefficients are very low in larvae of all species. In male nymphs correlation coefficients are on the same level in all species while the correlation coefficient level in female nymphs reflects the degree of independence of the development of characters. This defines the degree of manifestation of sexual dimorphism at the nymphal phase: the more rigid the connections between the characters the less number of characters shows sexual differences. At the phase of imago the lowest correlation coefficients are in I. persulcatus. This species displays most distinct differences in the morphology of females and males. On the basis of comparison of correlation and variability coefficients the functional role of the characters is discussed.

Animals↗

[Study of the relationship of parthenogenetic forms of lizards of the species Lacerta and proposed parental bisexual species in comparison of DNA segments, considered by the polymerase chain reaction with a single primer].

Due to some suggestion [8] the parthenogenesis in vertebrates is the result of interspecies hybridization, and some species seem to be the main candidates participating in this process. DNA parts, which may be revealed using polymerase chain reaction in AP-RAPD modification, were compared in parthenogenetic lizards forms and in supposed parental species for them. As it was shown by other authors and confirmed by us, arbitrary primed randomly amplified DNA products are species specific and may be used as a molecular taxonomic criterion. It was shown that each parthenogenetic species studied has the patterns containing only the bands of one or another supposed parents and no more. This is in favour of the hypothesis mentioned above. Investigation of 103 10-nucleotide primers in PCR was done.

Animals↗