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PubMed1994

Genetic basis and evolution of species-specific courtship song in the Drosophila auraria complex.

The interpulse interval (IPI) of courtship song in the Drosophila auraria complex is the only parameter that is consistently species-specific among the several courtship elements examined within the complex. The genetic basis of the species-specific courtship song was examined by analysing the song of interspecific hybrids and of backcross progeny. IPI of all interspecific hybrids except two showed intermediate values, suggesting autosomal control of species-specific IPI. However, significant deviation for shorter IPI from midparent was found in thirteen out of 20 crosses. The chromosomal analysis between D. auraria and D. biauraria revealed that the two major autosomes had significantly large effects on IPI, but the sex chromosome and cytoplasm had no effect. Since no interaction was detected, it is concluded that each autosome acts additively in the determination of species-specific IPI. The common ancestors of the D. auraria complex may also have had autosomal control of IPI, which has been conserved during speciation in the complex.

Animals↗
PubMed2005

Simultaneous multi-species determination of trimethyllead, monomethylmercury and three butyltin compounds by species-specific isotope dilution GC-ICP-MS in biological samples.

An accurate and sensitive multi-species species-specific isotope dilution GC-ICP-MS method was developed for the simultaneous determination of trimethyllead (Me3Pb+), monomethylmercury (MeHg+) and the three butyltin species Bu3Sn+, Bu2Sn2+, and BuSn3+ in biological samples. The method was validated by three biological reference materials (CRM 477, mussel tissue certified for butyltins; CRM 463, tuna fish certified for MeHg+; DORM 2, dogfish muscle certified for MeHg+). Under certain conditions, and with minor modifications of the sample pretreatment procedure, this method could also be transferred to environmental samples such as sediments, as demonstrated by analyzing sediment reference material BCR 646 (freshwater sediment, certified for butyltins). The detection limits of the multi-species GC-ICP-IDMS method for biological samples were 1.4 ng g(-1) for MeHg+, 0.06 ng g(-1) for Me3Pb+, 0.3 ng g(-1) for BuSn3+ and Bu3Sn+, and 1.2 ng g(-1) for Bu2Sn2+. Because of the high relevance of these heavy metal alkyl species to the quality assurance of seafood, the method was also applied to corresponding samples purchased from a supermarket. The methylated lead fraction in these samples, correlated to total lead, varied over a broad range (from 0.01% to 7.6%). On the other hand, the MeHg+ fraction was much higher, normally in the range of 80-100%. Considering that we may expect tighter legislative limitations on MeHg+ levels in seafood in the future, we found the highest methylmercury contents (up to 10.6 microg g(-1)) in two shark samples, an animal which is at the end of the marine food chain, whereas MeHg+ contents of less than 0.2 microg g(-1) were found in most other seafood samples; these results correlate with the idea that MeHg+ is usually of biological origin in the marine environment. The concentration of butyltins and the fraction of the total tin content that is from butyltins strongly depend on possible contamination, due to the exclusively anthropogenic character of these compounds. A broad variation in the butylated tin fraction (in the range of <0.3-49%) was therefore observed in different seafood samples. Corresponding isotope-labeled spike compounds (except for trimethyllead) are commercially available for all of these compounds, and since these can be used in the multi-species species-specific GC-ICP-IDMS method developed here, this technique shows great potential for routine analysis in the future.

Animals↗
PubMed1985

In vitro antigen-specific antibody response to the species-specific surface protein antigens of typhus group rickettsiae by human peripheral blood mononuclear cells: generation of an antigen-dependent suppressor T cell.

We defined conditions suitable for in vitro synthesis of rickettsia-specific antibody by human PBMC cultured with the SPA of Rickettsia typhi or R. prowazekii and without addition of mitogens or polyclonal stimulators. Antibody synthesis, as measured by an enzyme-linked immunosorbent assay, was cycloheximide-inhibitable and antigen-specific. PBMC from individuals with prior rickettsial infection made antibody, whereas PBMC from those receiving vaccine or with undetectable levels of serum anti-SPA antibody did not. Antibody production was T helper cell-dependent because isolated B cells did not generate antigen-specific antibody in the absence of autologous T cells. Furthermore, prior exposure of T cells to high concentrations of SPA led to the generation of an antigen-dependent population of cells capable of suppressing the anti-SPA response when co-cultured with autologous PBMC and optimal SPA concentrations. This system should serve as an effective tool for analyzing the cellular interactions involved in the in vitro regulation of antigen-specific antibody synthesis by human PBMC.

Antibodies, Bacterial↗
PubMed1996

Chimeric rat/human neurotensin receptors localize a region of the receptor sensitive to binding of a novel, species-specific, picomolar affinity peptide.

Recently, we reported the development of a species-specific neurotensin analog that displays selective binding affinity at the rat and human neurotensin (NT) receptor, L-[3,2'-Nal11]NT(8-13) (where Nal is naphthylalanine) (NT19). We have developed another neurotensin analog, L-[3,1'-Nal11]NT(8-13), (NT34), that exhibits a 126-fold difference in binding affinities between the rat and human receptors. This compound differs from our previous reported species-specific ligand in the steric positioning of the naphthyl ring on the L-alanine side chain. For NT34, the observed Kd values at the rat and human neurotensin receptors were 0.046 and 5.8 nM, respectively. In stimulating phosphatidylinositol turnover, the observed EC50 values were 2.8 nM and 130 nM in rat and human, respectively. We constructed a series of chimeric rat/human neurotensin receptor genes and expressed them by transient transfection into human embryonic kidney (HEK-293) cells. Radioligand binding assays were then performed using neurotensin and NT34. Our results led us to propose a region of the neurotensin receptor that may be involved in determining species specificity, i. e. the transmembrane VI, the third extracellular loop, and transmembrane VII regions of the neurotensin receptor.

Amino Acid Sequence↗
PubMed1988

[Somatotropin: structure, (bio)synthesis and species specificity].

The literature on biosynthesis and species specificity of bovine somatotropin (BST) is reviewed. Somatotropin is a hypophyseal hormone consisting of 190 amino acids, having, among other things, a stimulating effect on milk synthesis. Recombinant DNA-techniques have been used since 1982 to produce BST and this has paved the way for large-scale use of r-BST. It is assumed that the somatotropin molecule has several active sites responsible for a multitude of biological effects following interaction with specific receptors. Somatotropin of different animals have a varying amino acid composition. Sixty-five per cent of human and bovine somatotropins are homologues in amino acid sequence. BST is found to be virtually inactive when used therapeutically in human individuals.

Amino Acid Sequence↗
PubMed1998

Differential genome analysis applied to the species-specific features of Helicobacter pylori.

We introduce a simple and rapid strategy to identify genes that are responsible for species-specific phenotypes. The genome of a species that has a specific phenotype is compared with at least one, closely related, species that lacks this phenotype. Homologous genes that are shared among the species compared are identified and discarded from the list of candidates for species-specific genes. The process is automated and rapidly yields a small subset of the genome that likely contains genes responsible for the species-specific features. Functions are assigned to the genes, and dubious annotations are filtered out. Information is extracted not only from the presence of genes, but also from their absence with respect to known phenotypes. We have applied the technique to identify a set of species-specific genes in Helicobacter pylori by comparing it with its closest relatives for which complete genome sequences are available, Haemophilus influenzae and Escherichia coli. Of the genes of this set for which functional features can be obtained, a large fraction (63%, 123 proteins) is (potentially) involved in H. pylori's interaction with its host. We hypothesize that a family of outer membrane proteins is critical for the ability of H. pylori to colonize host cells in highly acidic environments.

Amino Acid Sequence↗
PubMed1992

Species-specific assessment of Mycobacterium leprae in skin biopsies by in situ hybridization and polymerase chain reaction.

Conventional histopathologic diagnosis of mycobacterial infections are limited to the determination of "acid-fast bacilli". A species-specific diagnosis is thus far impossible. In addition, routine microbiologic assessments of mycobacteria suffer from the major drawback that a species-specific diagnosis is extremely time-consuming and in several cases even impossible. As Mycobacterium leprae cannot be cultured in vitro, we tried to specifically target this obligate intracellular parasite by in situ hybridization and polymerase chain reaction (PCR) techniques. For this purpose we used a 22 mer oligonucleotide probe recognizing a species-specific sequence of the 16S rRNA of Mycobacterium leprae. Using an immunoenzymatic detection method for in situ hybridization we were able to specifically assess Mycobacterium leprae (a) in long-term cultured macrophages in vitro infected with different mycobacteria species and (b) in frozen sections of skin biopsies obtained from patients suffering from lepromatous leprosy. These results could be confirmed and extended by PCR experiments in which we used conserved oligonucleotide primers for 16S rRNA to amplify bacterial DNA isolated from different eubacterial species and from fresh-frozen as well as from formalin-fixed, paraffin-embedded and routinely processed mycobacteria-infected tissues. Upon Southern blot analysis, the Mycobacterium leprae-specific oligonucleotide probe exclusively hybridized with PCR products obtained from Mycobacterium leprae-containing samples (including paraffin sections), but not with PCR products obtained from samples containing other mycobacterial species. As species-specific oligonucleotide probes targeted at rRNA are described for a variety of mycobacterial species, these methods may be generally applied for a rapid species-specific assessment of mycobacteria in histologic material.

Base Sequence↗
PubMed2006

Estimation of the species-specific mutation rates at the DRB1 locus in humans and chimpanzee.

To estimate the species-specific mutation rates at the DRB1 locus in humans and chimpanzee, we analyzed the nucleotide sequence of a 37.6-kb chimpanzee chromosomal segment containing the entire Patr-DRB1*0701 allele and the flanking nongenic region and we compared it with two corresponding human sequences containing the HLA-DRB1*070101 allele using the sequence of HLA-DRB1*04011 as an outgroup. Because the allelic pair of HLA-DRB1*070101 and Patr-DRB1*0701 shows the lowest number of substitutions between the two species, it appears that these sequences diverged close to the time of the humans-chimpanzee divergence (6 million years ago). Alignment of the nucleotide sequences for HLA-DRB1*070101 and Patr-DRB1*0701 alleles showed that they share a high degree of similarity, suggesting that the studied chromosomal segments with these sequences have not been subjected to recombination since the humans-chimpanzee divergence. Comparison of the flanking 10.6 kb of nongenic sequences revealed an average of 41.5 and 83 single nucleotide substitutions in humans and chimpanzee, respectively. Thus, the species-specific nucleotide substitution rates in the flanking nongenic region were estimated to be 6.53 x 10(-10) and 1.31 x 10(-9) per site per year in humans and chimpanzee, respectively. Unexpectedly, the estimated rate in humans was twofold lower than in chimpanzee (P < 10(-3), Tajima's relative rate test) and lower than the average substitution rate in the human genome. Because the nucleotide substitution rate in nongenic regions free from selection is expected to be equal to the mutation rate, the estimated substitution rate should correspond to the species-specific mutation rate at the DRB1 locus. Our results strongly suggest that the mutation rate at DRB1 locus differs among species.

Alleles↗
PubMed1996

Species specificity of ribosomal gene transcription: a factor associated with human RNA polymerase I prevents transcription of mouse rDNA.

An intrinsic property of class I gene transcription by RNA polymerase I (Pol I) is the species specificity of the initiation reaction. Previous studies have demonstrated that species-specific rDNA promoter recognition is brought about by a TBP-TAF complex, termed TIF-IB in mouse and SL1 in man. We have compared the ability of affinity-purified TIF-IB and SL1 to direct transcription from the homologous rDNA template both in a reconstituted transcription system and in nuclear extracts prepared from mouse and human cells. We show that Pol I from both species and the individual transcription factors, with the exception of TIF-IB/SL1, are functionally interchangeable in the reconstituted transcription system containing purified proteins. In nuclear extracts, however, species-specific differences are obvious. Whereas SL1 reprograms a heterologous mouse extract to recognize the human promoter, TIF-IB fails to reprogram a human extract unless it is complemented with mouse Pol I. Crude human, but not mouse, Pol I exhibits species-specific differences that disappear after purification. We propose that in extracts and less purified fractions human Pol I exists as 'holoenzyme' containing associated protein(s) that prevent assembly of TIF-IB-directed initiation complexes at the murine rDNA promoter.

Animals↗
PubMed1981

A requirement for native (undenatured) IgG for detection of species specificity of the IgG-Fc receptor on lymphocytes.

The species specificity of the Fc receptor involved in binding of preformed antibody-antigen complexes was examined using complexes of deaggregated 7S antibodies and albumin antigens. Complexes prepared with mouse antibodies bound to 3-4 times as many cells as complexes prepared with rabbit, guinea pig, or goat antibodies. Using lymphocytes from each species, it was shown that homologous complexes consistently labeled a higher frequency of cells than heterologous complexes. The binding of heterologous complexes seemed to be generally restricted to monocytic populations which were also capable of binding monomeric 7S immunoglobulins. It is concluded that the lymphocytic Fc receptor for antigen-complexed 7S immunoglobulin displays strict species specificity. Heat aggregation of the heterologous immunoglobulins eliminated the species restriction on their binding to the lymphocytic Fc receptor. It is therefore suggested that artificially aggregated immunoglobulins may not be reliable probes for the specificity of the Fc receptors.

Animals↗
PubMed2004

Species-specific urokinase receptor ligands reduce glioma growth and increase survival primarily by an antiangiogenesis mechanism.

Species-specific urokinase receptor (uPAR) ligands with improved pharmacokinetics were generated by site-specific mutagenesis and amino-terminal pegylation. These molecules were used to probe the role of uPAR in brain tumor progression and angiogenesis. The ligands blocked endothelial cell tube formation in Matrigel in a species-specific manner and reduced both baseline and uPA amino-terminal fragment-stimulated cell migration on vitronectin gradients. Treatment of U87MG gliomas implanted orthotopically in mice with single species-specific or combination uPAR ligands resulted in significant decreases in tumor size, which translated to increases in survival time, and which were most significant when the murine-specific ligand was included. Further analysis of tumors showed that the reduced sizes were correlated with a decrease in tumor cell proliferation and mean vessel density and an increase in tumor cell apoptosis. In addition, a large increase in collagen deposition was observed in the treated groups. Statistical analysis showed that the combination therapy demonstrated a clear synergy as compared to the individual agent treatments. These results suggest that the major role of the uPAR system in brain tumor progression is in the stromal compartment and particularly in neovascularization, a hallmark of invasive brain tumors.

Animals↗
PubMed2003

Species-specific identification of campylobacters by partial 16S rRNA gene sequencing.

Species-specific identification of campylobacters is problematic, primarily due to the absence of suitable biochemical assays and the existence of atypical strains. 16S rRNA gene (16S rDNA)-based identification of bacteria offers a possible alternative when phenotypic tests fail. Therefore, we evaluated the reliability of 16S rDNA sequencing for the species-specific identification of campylobacters. Sequence analyses were performed by using almost 94% of the complete 16S rRNA genes of 135 phenotypically characterized Campylobacter strains, including all known taxa of this genus. It was shown that 16S rDNA analysis enables specific identification of most Campylobacter species. The exception was a lack of discrimination among the taxa Campylobacter jejuni and C. coli and atypical C. lari strains, which shared identical or nearly identical 16S rDNA sequences. Subsequently, it was investigated whether partial 16S rDNA sequences are sufficient to determine species identity. Sequence alignments led to the identification of four 16S rDNA regions with high degrees of interspecies variation but with highly conserved sequence patterns within the respective species. A simple protocol based on the analysis of these sequence patterns was developed, which enabled the unambiguous identification of the majority of Campylobacter species. We recommend 16S rDNA sequence analysis as an effective, rapid procedure for the specific identification of campylobacters.

Animals↗
PubMed2004

Identification of Carnobacterium species by restriction fragment length polymorphism of the 16S-23S rRNA gene intergenic spacer region and species-specific PCR.

The genus Carnobacterium is currently divided into the following eight species: Carnobacterium piscicola, C. divergens, C. gallinarum, C. mobile, C. funditum, C. alterfunditum, C. inhibens, and C. viridans. An identification tool for the rapid differentiation of these eight Carnobacterium species was developed, based on the 16S-23S ribosomal DNA (rDNA) intergenic spacer region (ISR). PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of this 16S-23S rDNA ISR was performed in order to obtain restriction profiles for all of the species. Three PCR amplicons, which were designated small ISR (S-ISR), medium ISR (M-ISR), and large ISR (L-ISR), were obtained for all Carnobacterium species. The L-ISR sequence revealed the presence of two tRNA genes, tRNA(Ala) and tRNA(Ile), which were separated by a spacer region that varied from 24 to 38 bp long. This region was variable among the species, allowing the design of species-specific primers. These primers were tested and proved to be species specific. The identification method based on the 16S-23S rDNA ISR, using PCR-RFLP and specific primers, is very suitable for the rapid low-cost identification and discrimination of all of the Carnobacterium species from other phylogenetically related lactic acid bacteria.

Animals↗
PubMed1998

Green fluorescent protein as a novel species-specific marker in enteric dual-species biofilms.

Green fluorescent protein (GFP) was used as a tool to examine the interactions between pairs of bacterial species and their effects on subsequent biofilm development over 24 h. A plasmid encoding GFP from Aequorea victoria was transformed into strains of Enterobacter agglomerans and Escherichia coli ATCC 11229. The development of dual-species biofilms, containing one fluorescent and one non-fluorescent partner, was examined using viable counts. UV illumination of plates enabled both species to be identified in a mixture. The spatial distribution of each species was examined by UV microscopy, simultaneously staining the non-fluorescent strain with propidium iodide. GFP fluorescence was measured to quantify the adhesion of the strains to other cells or cell constituents or the invasion into pre-existing biofilms. Co-operation between Ent. agglomerans/GFP and Klebsiella pneumoniae G1 resulted in a 54 and a 23% increase in biofilm formation, respectively, compared with single-species biofilms. E. coli/GFP and Serratia marcescens 87b stably co-existed in biofilms but did not affect the growth of each other. The other bacterial partnerships examined were competitive, with the end result that one species dominated the biofilm. The methods described provide a convenient technique for the examination of mixed-species biofilm communities where the unique interactions between species determine the true properties of the resultant biofilms.

Biofilms↗
PubMedDate not supplied

[Species-specific detection of Listeria monocytogenes by directed DNA amplification].

A highly sensitive species-specific test system which allows detection Listeria monocytogenes in animal tissues is elaborated using the principle of a polymerase chain reaction. The potentialities of its application were studied in the conditions of experimental infection of animals. It is shown that while the procedure of detection is relatively simple and fast, the test system is as sensitive and specific as traditional microbiological methods.

Animals↗
PubMed1994

The 5' flanking region of the rat beta 3-adrenergic receptor gene: divergence with the human gene and implications for species-specific gene expression.

beta 3-adrenergic receptor mRNAs exhibit species-specific expression (human vs. rodent) in distinct anatomical regions and appear to be expressed abundantly within rodent adipose tissue, but only at low levels within corresponding human tissues. In order to determine the genetic basis of the differential expression of the rat and human beta 3-adrenergic receptor genes, we cloned and sequence the rat gene and compared the 5' flanking regions of the two genes to identify potential discriminators in transcriptional regulation. We have found that the rat and human beta 3-adrenergic receptor 5' flanking regions are only 67% similar, unlike the close sequence similarity observed between the coding blocks (> 90%) and also observed between species for the 5' flanking regions of other beta-adrenergic receptor subtype genes (> 90%). In addition, the rat beta 3-adrenergic receptor gene lacks the four potential cAMP responsive elements identified within the 5' flanking region of the human receptor gene. The striking divergence in regulatory sequences between the rat and human beta 3-adrenergic receptor genes may potentially explain the differences in species-specific expression and tissue localization of the rat and human receptor mRNAs.

Animals↗
PubMedDate not supplied

Species-specific ultrastructure of neuronal lipofuscin in hippocampus and neocortex of subhuman mammals and humans.

Lipofuscin represents an integral part of neurons and glial cells in mammals and in submammalian species. It is a special lysosomal organelle, takes part of cellular metabolism, and is a structural expression of catabolic pathways. Species-specific differences of lipofuscin indicate metabolic differences of the relevant neurons. The authors have studied the ultrastructure of neuronal lipofuscin in the hippocampus and cerebral neocortex of dogs, horses, cows, elephants, rats, mice, apes, and humans to answer the question of species-specific differences of this organelle. Paraffin sections of formalin-fixed material were investigated by hematoxylin-eosin and PAS staining, by fluorescence microscopy for autofluorescence, with a laser scanning confocal microscope and by electron microscopy. In the animals studied and in humans the lipofuscin displayed, in addition to the general trilaminar substructure, species-specific appearances. No differences were found in the lipofuscin structure between neocortical and hippocampal neurons of the separate animal species. In contrast, in humans, neurons of the hippocampus showed a particular lipofuscin structure, not only different from the neocortical one, but also with differences between CA1 and CA3/4 sectors. Interestingly, in apes a transitional situation was found with slight differences between neocortical and hippocampal lipofuscin, especially in the rhesus monkey. This peculiarity was corroborated by the distribution of special pentilaminar linear structures in the lipofuscin pigment in all animals, only sparsely in the rhesus monkey and not in humans. The results indicate that lipofuscin ultrastructure of neocortical and hippocampal neurons is species specific and that lipofuscin in the human hippocampal neurons displays structures characteristic of man differing from the neocortical neuronal lipofuscin. The neuronal lipofuscin of apes, especially of the rhesus monkey displays structures in between humans and lower mammals. Nothing is known about the functional significance of these findings. They may indicate metabolic and/or functional characteristics of the relevant neurons.

Adult↗