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At least 757 records · Page 42Linked to original sources
PubMed1990

A new approach to the phylogeny of Leishmania: species specificity of glycoconjugate ligands for promastigote internalization into murine macrophages.

Two Leishmania donovani glycoconjugate ligands for the internalization receptor on BALB/c peritoneal macrophages [fucose-mannose ligand (FML) and phosphate mannogalactan ligand (PMGL)] were shown to be species-specific in a comparative phagocytosis-inhibition test. Promastigotes of L. donovani Sudan (LD1S), L. infantum, L. d. donovani, L. major (Jericho and Sudan), L. tropica, L. chagasi, L. mexicana venezuelensis, L. m. mexicana, L. m. amazonensis, L. m. pifanoi, L. m. garnhami, L. braziliensis braziliensis, L. m. amazonensis (Josefa), L. enrietti or L. adleri were incubated with macrophages in the presence of 10 micrograms/ml FML and PMGL purified from L. donovani (LD1S). Parasite internalization was determined and compared with that obtained in control experiments. Specific inhibition of phagocytosis ranged from 83% (L. donovani LD1S) to 7% (L. m. amazonensis). We could distinguish groups of Leishmania consistently with their geographic distribution and the clinical aspects of the disease. Analogous experiments with L. m. amazonensis glycoconjugates showed reciprocal results, with inhibition ranging from 76% (L. m. amazonensis) to 8% (L. donovani LD1S). L. chagasi remained separated from the Old World kala-azar agents. Possible phylogenetic implications of these observations are discussed.

Animals↗
PubMed2004

Comparative functional characterization of the feline foamy virus transactivator reveals its species specificity.

Foamy virus (FV) Bel1/Tas transactivators act as key regulators of gene expression and directly bind DNA Bel1 response elements (BREs) in both the internal (IP) and 5'LTR promoters. Here, we report the mapping and the virus species specificity of the nonhomologous feline foamy virus (FFV) BREs in both promoters. The data indicate that FFV Bel1 did not bind the primate FV IP.BRE and that primate FV Bel1 was not capable of binding the FFV IP.BRE. In addition, we show that the C-terminal activation domain of FFV Bel1 does not contribute to DNA binding because a C-terminal trans-dominant negative FFV Bel1 mutant was still able to bind to both promoters.

5' Untranslated Regions↗
PubMedDate not supplied

Reaction of cats to species-specific acoustic signals during electrical stimulation of the hypothalamus before and after ablation of the sensorimotor region of the cortex.

The possibility of the formation under chronic experimental conditions of a reaction of a selective character to species-specific acoustic signals (SAS) of the agonistic type, presented to cats against the background of subthreshold electrical stimulation of hypothalamic divisions, was demonstrated. Reactions appropriate to the SAS presented appeared only in those animals in which threshold electrical stimulation evoked directed aggressive reactions. Partial bilateral ablation of the sensorimotor region of the cortex (SMC) did not influence the selective character of the reaction to the SAS, but led to a change by comparison with the preoperative period in the relationship of the motoric and acoustic reactions of the agonist type to conjoint acoustic and electrical stimulation.

Acoustic Stimulation↗
PubMed1971

Species specificity of phosphate triester anticholinesterases.

Two widely distributed enzyme systems degrade phosphate triester anticholinesterase agents to inactive phosphate diesters by nonhydrolytic mechanisms. The substrate specificity of these enzymes is discussed and the level of activity in various mammalian livers is described. The distribution of these enzymes is an important factor in accounting for the species specificity of at least some anticholinesterase agents.

Animals↗
PubMed2004

Species-specific calls evoke asymmetric activity in the monkey's temporal poles.

It has often been proposed that the vocal calls of monkeys are precursors of human speech, in part because they provide critical information to other members of the species who rely on them for survival and social interactions. Both behavioural and lesion studies suggest that monkeys, like humans, use the auditory system of the left hemisphere preferentially to process vocalizations. To investigate the pattern of neural activity that might underlie this particular form of functional asymmetry in monkeys, we measured local cerebral metabolic activity while the animals listened passively to species-specific calls compared with a variety of other classes of sound. Within the superior temporal gyrus, significantly greater metabolic activity occurred on the left side than on the right, only in the region of the temporal pole and only in response to monkey calls. This functional asymmetry was absent when these regions were separated by forebrain commissurotomy, suggesting that the perception of vocalizations elicits concurrent interhemispheric interactions that focus the auditory processing within a specialized area of one hemisphere.

Acoustic Stimulation↗
PubMed2005

Human C4b-binding protein selectively interacts with Neisseria gonorrhoeae and results in species-specific infection.

Neisseria gonorrhoeae is the causative agent of gonorrhea, a disease that is restricted to humans. Complement forms a key arm of the innate immune system that combats gonococcal infections. N. gonorrhoeae uses its outer membrane porin (Por) molecules to bind the classical pathway of complement down-regulatory protein C4b-binding protein (C4bp) to evade killing by human complement. Strains of N. gonorrhoeae that resisted killing by human serum complement were killed by serum from rodent, lagomorph, and primate species, which cannot be readily infected experimentally with this organism and whose C4bp molecules did not bind to N. gonorrhoeae. In contrast, we found that Yersinia pestis, an organism that can infect virtually all mammals, bound species-specific C4bp and uniformly resisted serum complement-mediated killing by these species. Serum resistance of gonococci was restored in these sera by human C4bp. An exception was serotype Por1B-bearing gonococcal strains that previously had been used successfully in a chimpanzee model of gonorrhea that simulates human disease. Por1B gonococci bound chimpanzee C4bp and resisted killing by chimpanzee serum, providing insight into the host restriction of gonorrhea and addressing why Por1B strains, but not Por1A strains, have been successful in experimental chimpanzee infection. Our findings may lead to the development of better animal models for gonorrhea and may also have implications in the choice of complement sources to evaluate neisserial vaccine candidates.

Amino Acid Sequence↗
PubMed1996

A novel 95-kilodalton antigen of Wuchereria bancrofti infective larvae identified by species-specific monoclonal antibodies.

CBA and BALB/c mice produced polyspecific and monospecific polyclonal antibody responses, respectively, following immunization with Wuchereria bancrofti stage-3 larvae. Two monoclonal antibodies (MAbs) were produced from the immunized BALB/c mouse. These MAbs (both isotype M) recognized a previously undescribed highly expressed W. bancrofti antigen present in stage-3 larvae. The epitopes bound by the MAbs appear to be species specific for W. bancrofti since the MAbs did not bind to antigens of either nine other nematode species or two vector species in Western blots (immunoblots). Phosphorylcholine epitopes, responsible for immunological cross-reactivity among nematodes, were identified only on a 200-kDa antigen and not on the 95-kDa molecule. The targets of these immunoglobulin M MAbs are not carbohydrate epitopes.

Animals↗
PubMed1989

Generation of species-specific antihemoglobin antibodies by immunization with synthetic peptides of human hemoglobin.

Four peptides (7-16 residues) representing nonconserved regions of human hemoglobin (Hb) were selected for synthesis by comparison of the amino acid sequence of human Hb with those of the most common domesticated animals. Mouse antisera resulting from immunization with the synthetic peptides were investigated for binding to a panel of animal Hbs using solid-phase radioimmunoassay (RIA). One of the peptides elicited antibodies which bound specifically to human Hb, but not to any Hb of the nonprimate animals tested. The results show that the peptide immunogen chosen on the basis of dissimilarity between regions of different species is useful for the generation of species-specific antibodies. Such antibodies could serve as valuable tools for clinical screening of fecal occult blood trait and for forensic identification of bloodstains of human origin.

Amino Acid Sequence↗
PubMedDate not supplied

[Effect of glutaraldehyde on the species-specific antigenicity of xenogeneic cartilage].

Present results showed that an extract of xenogeneic cartilage may inhibit the complement activity of human serum, while an extract of xenogeneic cartilage treated with glutaraldehyde may enhance this effect. This finding suggested that treatment with glutaraldehyde does not decrease species-specific antigenicity of xenogeneic cartilage.

Aldehydes↗
PubMed2004

Quantification of Fusarium graminearum in infected wheat by species specific real-time PCR applying a TaqMan Probe.

A new real-time PCR based method was developed for the species-specific detection, identification and quantification of Fusarium graminearum in planta. It utilizes a TaqMan hybridisation probe targeting the beta-tubulin gene and a plasmid standard. The assay is highly specific giving no product with DNA of closely related species. It is very sensitive, detecting down to five gene copies per reaction, and is able to produce reliable quantitative data over a range of six orders of magnitude.

DNA, Fungal↗
PubMed2001

Trypanosoma vivax: characterization of the spliced-leader gene of a Brazilian stock and species-specific detection by PCR amplification of an intergenic spacer sequence.

The sequence of the spliced-leader gene repeat of a Brazilian Trypanosoma vivax stock from cattle showed high similarity to sequences of West African T. vivax in both intron and intergenic sequences. This is the first evidence based on DNA sequences of close-relatedness between Brazilian and West African T. vivax stocks. A T. vivax-specific diagnostic PCR assay based on spliced-leader gene intergenic sequences was able to amplify DNA from T. vivax stocks from South America (Brazil, Bolivia, and Colombia) and West Africa. Species-specificity of this method was confirmed by results obtained by testing 15 other trypanosomes, including other species and subspecies that can also infect cattle. The PCR assay developed presented high sensitivity, detecting the DNA content of only one parasite and also revealing T. vivax infection in asymptomatic animals without detectable parasitemia by microhematocrit or in Giemsa-stained blood smears. Use of crude preparations from field-blood samples collected on both filter paper and glass slides as DNA template suggested that this method could be useful for the diagnosis of T. vivax in large epidemiological studies.

Animals↗
PubMedDate not supplied

Formation and reactivity of alternative quinone methides from butylated hydroxytoluene: possible explanation for species-specific pneumotoxicity.

Previous work has shown that butylated hydroxytoluene [2,6-di-tert-butyl-4-methylphenol (BHT)] undergoes pi-oxidation in liver microsomes to form the quinone methide 2,6-di-tert-butyl-4-methylene-2,5-cyclohexadienone (QM). This electrophilic species binds covalently to glutathione and protein thiols and is believed to initiate pulmonary toxicity in mice. In the present investigation, we identified another quinone methide metabolite of BHT, 6-tert-butyl-2-(hydroxy-tert-butyl)-4-methylene-2,5-cyclohexadienone (QM-OH), formed subsequent to the microsomal hydroxylation of BHT at a tert-butyl group. Mouse liver and lung microsomes generate the two quinone methides, and evidence was obtained that both metabolites also are formed in vivo. In contrast, rat microsomes produce QM almost exclusively, with only traces of QM-OH formed in liver and none in lung. Studies of the chemical reactivities of the two quinone methides with GSH demonstrated that QM-OH reacts about 6-fold faster than QM. Infrared spectra, 1H NMR spectra, and electrochemical measurements all support the proposal that the enhanced electrophilicity of QM-OH is due to intramolecular hydrogen bonding of the ring oxygen with the side-chain hydroxyl. The results provide evidence, therefore, that the previous metabolic scheme for bioactivation of BHT to a pulmonary toxin should be amended to include tert-butyl hydroxylation and subsequent pi-oxidation to the activated electrophile QM-OH. This scheme is consistent with published data concerning BHT-induced pulmonary toxicity and provides an explanation for the species specificity of this effect.

Animals↗
PubMed2001

Production of a species specific monoclonal antibody against a 56-kDa Mycobacterium marinum antigen which is potentially useful in culture identification.

A monoclonal antibody (MoAb) designated 1H11 has been produced against a 56-kDa antigen from Mycobacterium marinum. This MoAb has been shown to be species specific by both enzyme-linked immunosorbent assay and Western blot. The relationship of this 56 kDa to other known mycobacterial antigens is currently under investigation. MoAb 1H11 recognised bacilli taken from cultures by both immunofluorescence and immunoperoxidase staining. This MoAb 1H11 may provide a simple method for rapid identification of M. marinum from cultures of clinical isolates.

Animals↗
PubMed1998

Genetic code in evolution: switching species-specific aminoacylation with a peptide transplant.

The genetic code is established in aminoacylation reactions whereby amino acids are joined to tRNAs bearing the anticodons of the genetic code. Paradoxically, while the code is universal there are many examples of species-specific aminoacylations, where a tRNA from one taxonomic domain cannot be acylated by a synthetase from another. Here we consider an example where a human, but not a bacterial, tRNA synthetase charges its cognate eukaryotic tRNA and where the bacterial, but not the human, enzyme charges the cognate bacterial tRNA. While the bacterial enzyme has less than 10% sequence identity with the human enzyme, transplantation of a 39 amino acid peptide from the human into the bacterial enzyme enabled the latter to charge its eukaryotic tRNA counterpart in vitro and in vivo. Conversely, substitution of the corresponding peptide of the bacterial enzyme for that of the human enabled the human enzyme to charge bacterial tRNA. This peptide element discriminates a base pair difference in the respective tRNA acceptor stems. Thus, functionally important co-adaptations of a synthetase to its tRNA act as small modular units that can be moved across taxonomic domains and thereby preserve the universality of the code.

Amino Acyl-tRNA Synthetases↗
PubMed2004

Application of a species-specific PCR-RFLP to identify Ancylostoma eggs directly from canine faeces.

Apart from their veterinary importance, the hookworms Ancylostoma caninum, Ancylostoma braziliense and Ancylostoma caninum are also capable of causing zoonotic disease in humans. A highly sensitive and species-specific PCR-RFLP technique was utilised to detect and differentiate the various canine Ancylostoma spp directly from eggs in faeces. This technique was utilised to screen 101 canine faecal samples from parasite endemic tea growing communities in Assam, India, as part as an ongoing epidemiological investigation into canine parasitic zoonoses. The prevalence of hookworms in dogs was found to be 98% using a combination of PCR and conventional microscopy. Overall, 36% of dogs were found positive for single hookworm infections with A. caninum, 24% positive for single infections with A. braziliense and 38% had mixed infections with both A. caninum and A. braziliense. No dogs were found positive for A. ceylanicum in the community under study. The high prevalence of A. caninum and A. braziliense in dogs in this community may account for the high incidence of cutaneous larva migrans (CLM) observed among the human population residing at the tea estates. The PCR-RFLP technique described herein allows epidemiological screening of canine hookworms to be conducted rapidly, with ease and accuracy, and has the potential to be applied to a number of different clinical, pharmacological and epidemiological situations.

Ancylostoma↗
PubMed2005

Prenatal auditory enrichment with species-specific calls and sitar music modulates expression of Bcl-2 and Bax to alter programmed cell death in developing chick auditory nuclei.

Postnatal auditory stimulation influences early perceptual learning. Previously we reported morphological effects of prenatal auditory stimulation by species-specific and sitar musical sounds on the chick brainstem auditory nuclei-nucleus magnocellularis and nucleus laminaris. At hatching, these two nuclei of auditory enriched embryos showed higher neuronal numbers, amongst other morphological changes. There were also increases in synaptophysin and syntaxin1 expressions in the sound enriched groups and modulation of the developmental expression of transcription factors c-Fos and c-Jun. We hypothesized that prenatal auditory enrichment may have reduced embryonic apoptosis in these nuclei with possible alteration of molecular mechanisms enhancing the postsynaptic neuron's ability to survive. In the present study, therefore, we examined apoptotic cell death by TUNEL technique and Bcl-2 expression using immunohistochemistry and immunoblotting. In the controls, a peak percentage in the TUNEL-positive cells was noted in the auditory nuclei at embryonic day 12, which was reduced at embryonic day 16. Bcl-2 immunoreactivity decreased from embryonic day 8 to embryonic day 12 overlapping the period of embryonic cell death in these nuclei. The stimulated groups, however, showed fewer apoptotic neurons and higher Bcl-2 level than that in the controls. On the other hand, Bax immunohistochemistry showed correlated reverse changes compared to Bcl-2 expression. Thus prenatal extra-acoustic stimulation appears to alter Bcl-2 and Bax expression to support cell survival and differentiation, thereby augmenting the development of auditory nuclei.

Acoustic Stimulation↗
PubMed2004

A human and mouse pregnane X receptor reporter gene assay in combination with cytotoxicity measurements as a tool to evaluate species-specific CYP3A induction.

Recent studies have demonstrated that a member of the nuclear receptor family, pregnane X receptor (PXR) is a key regulator of the expression of cytochrome P450 3A (CYP3A) in humans and rodents. It is also known that species specificity in the induction of CYP3A by xenobiotics is likely a consequence of differences at the level of PXR activation. Because of the importance of CYP3A4 in drug metabolism, the development of rapid and accurate in vitro assays for predicting the effects of compounds on CYP3A4 expression or activity in humans has been a long-standing goal within pharmaceutical industries. PXR activation measurements using an in vitro reporter gene approach appears to provide a rapid and relatively inexpensive means for predicting whether compounds will induce CYP3A levels in vivo. In this study, using an HepG2 cell based human and mouse PXR reporter gene assay, 23 compounds were tested for their potential to activate hPXR or mPXR. Data demonstrated that potent activators of hPXR had virtually no activity on mPXR and efficient activators of mPXR had weak activity on hPXR. In addition, a third category of moderate/weak activators of both hPXR and mPXR was identified. Exemestane was a strong activator of mPXR ( approximately 22-fold activation) with only minor effect on hPXR ( approximately 5-fold activation). The importance of cell viability measurements as part of the PXR reporter gene assay was demonstrated as significant cytotoxicity or inhibition of cell proliferation might underestimate the potential for PXR activation.

Androstadienes↗
PubMed1982

Species specific differences in the toxicity of mithramycin, chromomycin A3, and olivomycin towards cultured mammalian cells.

Three structurally related anticancer drugs, mithramycin, chromomycin A3, and olivomycin, showed large unexpected differences (up to more than 1000 fold) in their toxicity towards cultured cells from various species (human, Chinese hamster, Syrian hamster, and mouse). Among the cell types examined, human cells (both a diploid fibroblast cell strain and HeLa cells) were maximally sensitive to all these drugs, followed by the Syrian hamster kidney cells (BHK 21). The mouse (LMTK- cells) and Chinese hamster (CHO) cells, which were more resistant, showed interesting differences in their sensitivity towards these drugs. For example, whereas the mouse cells were more resistant to mithramycin than CHO cells, the sensitivity pattern was reversed for both chromomycin A3 and olivomycin. In cell extracts derived from human, mouse, and Chinese hamster cells RNA synthesis, which is the cellular target of these drugs, showed identical sensitivity to both mithramycin and chromomycin A3, indicating that the species specific differences in the toxicity to these drugs are at the level of cellular entry of these compounds. Based on the structures of these glycosidic antibiotics and their patterns of toxicity, it is suggested that the intracellular transport of these drugs involves specific interactions between the sugar residues on these compounds and some type of cell surface receptor(s), which differ among different cell types. Some implications of these results for toxicity studies are discussed.

Animals↗