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At least 199 records · Page 11Linked to original sources
PubMed2005

Phenotypic and DNA sequence data comparisons reveal three discrete species in the Ceratocystis polonica species complex.

Ceratocystis polonica and C. laricicola are two morphologically similar species that occur on conifers and reside in the Ceratocystis coerulescens species complex. They, however, represent two ecologically distinct entities. C. polonica causes blue stain on Norway spruce (Picea abies) and other spruce species (Picea spp.) in Eurasia and is associated with the bark beetles Ips typographus, I. typographus japonicus, I. amitinus and I. duplicatus. In contrast, C. laricicola lives in a symbiotic relationship with the bark beetles Ips cembrae and I. subelongatus that infest various larch species (Larix spp.). The objective of this study was to consider the phylogenetic relationships of C. polonica and C. laricicola and more specifically to determine the identity of Japanese isolates from both spruce and larch, based on sequences derived from the ITS regions of the rRNA operon, the beta-tubulin gene and the HMG box of the MAT-2 gene. Isolates were also compared based on morphology and cultural characteristics. Comparisons of anamorph and teleomorph structures confirmed that C. polonica and C. laricicola are indistinguishable based on morphology. Both species had an optimal growth temperature of 25 degrees C. However, at temperatures between 31-33 degrees, C. polonica isolates grew slowly or not at all, while C. laricicola isolates grew more actively at these temperatures. Thus, a growth test at 32 degrees can differentiate these species. Phylograms generated using parsimony for the three gene regions were strongly congruent. These showed three distinct clades supported by high bootstrap values. Two of the clades clearly separate C. laricicola from Europe and C. polonica, supporting the view that they represent two discrete taxa. A third clade included isolates obtained from galleries of Ips subelongatus on Larix kaempferi in Japan. This fungus clearly represents a discrete taxon that is closely related to, but distinct from C. laricicola, which is described here as C. fujiensis sp. nov.

Animals↗
PubMed2005

A new species of Hypocrella, H. macrostroma, and its phylogenetic relationships to other species with large stromata.

Two specimens of a new species of Hypocrella with large stromata were collected in Bolivia and Costa Rica. The morphology of the new species, H. macrostroma sp. nov., was compared with that of other species with large stromata, i.e. H. africana, H. gaertneriana, and H. schizostachyi. In addition, phylogenetic analyses of partial sequences from three genes, large subunit nuclear ribosomal DNA (LSU), translation elongation factor 1-alpha (EF1-alpha), and RNA polymerase II subunit 1 (RPB1), were conducted to determine the relationships of the new species to other species of Hypocrella/Aschersonia. Phylogenetic analyses show that H. macrostroma belongs to a strongly supported clade that includes H. africana, H. schizostachyi, and Aschersonia insperata, whereas other Hypocrella species belong to two sister clades. Hypocrella macrostroma is described and illustrated, and a lectotype is designated for H. gaertneriana.

Animals↗
PubMed2005

Fish species identification using PCR-RFLP analysis and lab-on-a-chip capillary electrophoresis: application to detect white fish species in food products and an interlaboratory study.

Identification of 10 white fish species associated with U.K. food products was achieved using PCR-RFLP of the mitochondrial cytochrome b gene. Use of lab-on-a-chip capillary electrophoresis for end-point analysis enabled accurate sizing of DNA fragments and identification of fish species at a level of 5% (w/w) in a fish admixture. One restriction enzyme, DdeI, allowed discrimination of eight species. When combined with NlaIII and HaeIII, specific profiles for all 10 species were generated. The method was applied to a range of products and subjected to an interlaboratory study carried out by five U.K. food control laboratories. One hundred percent correct identification of single species samples and six of nine admixture samples was achieved by all laboratories. The results indicated that fish species identification could be carried out using a database of PCR-RFLP profiles without the need for reference materials.

Animals↗
PubMed2005

Multiplex PCR method for use in real-time PCR for identification of fish fillets from grouper (Epinephelus and Mycteroperca species) and common substitute species.

Mitochondrial 16S rRNA sequences from morphological validated grouper (Epinephelus aeneus, E. caninus, E. costae, and E. marginatus; Mycteroperca fusca and M. rubra), Nile perch (Lates niloticus), and wreck fish (Polyprion americanus) were used to develop an analytical system for group diagnosis based on two alternative Polymerase Chain Reaction (PCR) approaches. The first includes conventional multiplex PCR in which electrophoretic migration of different sizes of bands allowed identification of the fish species. The second approach, involving real-time PCR, produced a single amplicon from each species that showed different Tm values allowing the fish groups to be directly identified. Real-time PCR allows the quick differential diagnosis of the three groups of species and high-throughput screening of multiple samples. Neither PCR system cross-reacted with DNA samples from 41 common marketed fish species, thus conforming to standards for species validation. The use of these two PCR-based methods makes it now possible to discriminate grouper from substitute fish species.

Animals↗
PubMed2004

Testing species boundaries in an ancient species complex with deep phylogeographic history: genus Xantusia (Squamata: Xantusiidae).

Identification of species in natural populations has recently received increased attention with a number of investigators proposing rigorous methods for species delimitation. Morphologically conservative species (or species complexes) with deep phylogenetic histories (and limited gene flow) are likely to pose particular problems when attempting to delimit species, yet this is crucial to comparative studies of the geography of speciation. We apply two methods of species delimitation to an ancient group of lizards (genus Xantusia) that occur throughout southwestern North America. Mitochondrial cytochrome b and nicotinamide adenine dinucleotide dehydrogenase subunit 4 gene sequences were generated from samples taken throughout the geographic range of Xantusia. Maximum likelihood, Bayesian, and nested cladogram analyses were used to estimate relationships among haplotypes and to infer evolutionary processes. We found multiple well-supported independent lineages within Xantusia, for which there is considerable discordance with the currently recognized taxonomy. High levels of sequence divergence (21.3%) suggest that the pattern in Xantusia may predate the vicariant events usually hypothesized for the fauna of the Baja California peninsula, and the existence of deeply divergent clades (18.8%-26.9%) elsewhere in the complex indicates the occurrence of ancient sundering events whose genetic signatures were not erased by the late Wisconsin vegetation changes. We present a revised taxonomic arrangement for this genus consistent with the distinct mtDNA lineages and discuss the phylogeographic history of this genus as a model system for studies of speciation in North American deserts.

Animals↗
PubMed2003

Evolution of the bacterial species Lactobacillus delbrueckii: a partial genomic study with reflections on prokaryotic species concept.

The species Lactobacillus delbrueckii consists at present of three subspecies, delbrueckii, lactis and bulgaricus, showing a high level of DNA-DNA hybridization similarity but presenting markedly different traits related to distinct ecological adaptation. The internal genetic heterogeneity of the bacterial species L. delbrueckii was analyzed. Phenotypic and several genetic traits were investigated for 61 strains belonging to this species. These included 16S rDNA sequence mutations, expression of beta-galactosidase and of the cell wall-anchored protease, the characterization of the lactose operon locus and of the sequence of lacR gene, galactose metabolism, and the distribution of insertion sequences. The high genetic heterogeneity of taxa was confirmed by every trait investigated: the lac operon was completely deleted in the subsp. delbrueckii, different mutation events in the repressor gene of the operon led to a constitutive expression of lacZ in the subsp. bulgaricus. Structural differences in the same genetic locus were probably due to the presence of different IS elements in the flanking regions. The different expression of the cell wall-anchored protease, constitutive in the subsp. bulgaricus, inducible in the subsp. lactis, and absent in the subsp. delbrueckii was also a consequence of mutations at the gene level. The galT gene for galactose metabolism was found only in the subsp. lactis, while no specific amplification product was detected in the other two subspecies. All these data, together with the absence of a specific IS element, ISL6, from the major number of strains belonging to the subsp. bulgaricus, confirmed a deep internal heterogeneity among the three subspecies. Moreover, this evidence and the directional mutations found in the 16S rDNA sequences suggested that, of the three subspecies, L. delbrueckii subsp. lactis is the taxon closer to the ancestor. Limitations of the current prokaryotic species definition were also discussed, based on presented evidences. Our results indicate the need for an accurate investigation of internal heterogeneity of bacterial species. This study has consequences on the prokaryotic species concept, since genomic flexibility of prokaryotes collides with a stable classification, necessary from a scientific and applied point of view.

Amino Acid Sequence↗
PubMed2006

Genome-wide patterns of expression in Drosophila pure species and hybrid males. II. Examination of multiple-species hybridizations, platforms, and life cycle stages.

Species often produce sterile hybrids early in their evolutionary divergence, and some evidence suggests that hybrid sterility may be associated with deviations or disruptions in gene expression. In support of this idea, many studies have shown that a high proportion of male-biased genes are underexpressed, compared with non-sex-biased genes, in sterile F1 male hybrids of Drosophila species. In this study, we examined and compared patterns of misexpression in sterile F1 male hybrids of Drosophila simulans and 2 of its sibling species, Drosophila mauritiana and Drosophila sechellia, at both the larval and adult life stages. We analyzed hybrids using both commercial Drosophila melanogaster microarrays and arrays we developed from reverse transcriptase-polymerase chain reactions of spermatogenesis and reproduction-related transcripts from these species (sperm array). Although the majority of misexpressed transcripts were underexpressed, a disproportionate number of the overexpressed transcripts were located on the X chromosome. We detected a high overlap in the genes misexpressed between the 2 species pairs, and our sperm array was better at detecting such misexpression than the D. melanogaster array, suggesting possible weaknesses in the use of an array designed from another species. We found only minimal misexpression in the larval samples with the sperm array, suggesting that disruptions in spermatogenesis occur after this life stage. Further study of these misexpressed loci may allow us to identify precisely where disruptions in the spermatogenesis pathway occur.

Animals↗
PubMed1988

Evolutionary conservation of the chromosomal configuration and regulation of amylase genes among eight species of the Drosophila melanogaster species subgroup.

Nuclear DNA was extracted from each of the eight species comprising the Drosophila melanogaster species subgroup. Southern hybridization of this DNA by using a molecular probe specific for the alpha-amylase coding region showed that the duplicated structure of the amylase locus, first found in D. melanogaster, is conserved among all species of the melanogaster subgroup. Evidence is also presented for the concerted evolution of the duplicated genes within each species. In addition, it is shown that the glucose repression of amylase gene expression, which has been extensively studied in D. melanogaster, is not confined to this species but occurs in all eight members of the species subgroup. Thus, both the duplicated gene structure and the glucose repression of Drosophila amylase gene activity are stable over extended periods of evolutionary time.

Amylases↗
PubMed1980

Photosynthesis in Grass Species Differing in Carbon Dioxide Fixation Pathways: III. OXYGEN RESPONSE AND ENZYME ACTIVITIES OF SPECIES IN THE LAXA GROUP OF PANICUM.

Measurements of CO(2) exchange at varying O(2) concentrations in seven grass species of the Laxa group of Panicum and activities of five photosynthetic enzymes were compared to values obtained for these characters in a cool season C(3) grass, tall fescue (Festuca arundinacea Schreb.) and a C(4) grass, P. maximum Jacq. Plants were divided into three groups on the basis of the inhibition of apparent photosynthesis by 21% O(2.) Rates of apparent photosynthesis in P. prionitis Griseb. and P. maximum were virtually unaffected by changes in O(2) concentration. In another group consisting of P. hylaeicum Mez., P. rivulare Trin., P. laxum Sw., and tall fescue apparent photosynthesis was inhibited by 28.2 to 36.0% at 21% O(2.) An intermediate inhibition of 20.6 to 23.3% at 21% O(2) was exhibited by P. milioides Nees ex Trin., P. schenckii Hack., and P. decipiens Nees ex Trin. The CO(2) compensation concentration for P. prionitis and P. maximum was low (</=6 microliters per liter CO(2) at 21% O(2)) and affected little by O(2), whereas values for P. hylaeicum, P. rivulare, P. laxum, and tall fescue were much greater, and increased almost linearly from 2 to 48% O(2.) Values for P. milioides, P. schenckii, and P. decipiens were intermediate to the other two groups. The effect of O(2) on total leaf conductance to CO(2) was similar to the C(3) grasses and the intermediate Panicums. However, estimates of photorespiration in the intermediate species were low and changed little with O(2) in comparison to estimates for the C(3) species which were higher and increased greatly with increased O(2.)Activities of phosphoenolpyruvate carboxylase were greatest in P. maximum and P. prionitis and one-fourth or less in the remaining species. Activity of ribulose bisphosphate carboxylase was 548 micromoles per mg chlorophyll per hour in tall fescue; activity in the remaining species was approximately one-fourth or less of that in tall fescue, with the exception of P. rivulare, in which it was 440 micromoles per milligram chlorphyll per hour. High activities of two C(4) decarboxylating enzymes, phosphoenolpyruvate carboxykinase and NADP-malic enzyme, were observed in P. maximum (1,988 micromoles per milligram chlorophyll per hour) and P. prionitis (125 micromoles per milligram chlorophyll per hour), respectively. Only minimal activities of decarboxylating enzymes were detected in the remaining species.

Journal Article↗
PubMed1981

Photosynthesis of Grass Species Differing in Carbon Dioxide Fixation Pathways : VII. CHROMOSOME NUMBERS, METAPHASE I CHROMOSOME BEHAVIOR, AND MODE OF REPRODUCTION OF PHOTOSYNTHETICALLY DISTINCT PANICUM SPECIES.

Panicum species of the Laxa group were investigated in a series of published reports and were found to possess C(4), C(3), and intermediate photosynthetic characteristics. Taxonomic and other relationships among these plants, however, are not clear. It was the objective of this investigation to document chromosome number, metaphase I chromosome behavior, and mode of reproduction, including abnormalities in the embryo sac, for these species.Chromosome counts showed a basic number (x) of 10 and ploidy levels of diploid (2n = 2x = 20), tetraploid (2n = 4x = 40), and hexaploid (2n = 6x = 60) in this group of Panicum. One diploid and one tetraploid accession of the C(4) species, Panicum prionitis Griseb., were obtained. Of the intermediate species, Panicum milioides Nees ex Trin. was diploid, Panicum schenckii Hack. was hexaploid, and Panicum decipiens Nees, ex Trin. was found to possess two ploidy levels, one accession being diploid and the other accession being hexaploid. All the C(3) species, which included two accessions of Panicum laxum Sw., three accessions of Panicum hylaeicum Mez., and one accession of Panicum rivulare Trin., were tetraploid.Meiosis was regular with primarily bivalent pairing at metaphase I in all species except the tetraploid accession of P. prionitis which possessed from 4 to 10 tetravalents. Stainable pollen was high in all species, ranging from 70 to 99%. Embryo sac analyses showed a single sac in all plants except the tetraploid accession of P. prionitis, which was found to possess an additional sac at anthesis. An additional sac was also observed in some ovaries of the P. schenckii accession. Self-pollinated seed set was high in all accessions except the diploid accession of P. prionitis and one accession of P. laxum where no seed was set under bagged conditions.This information establishes, within the limits of this collection, a base for future studies on genetic, taxonomic, photosynthetic, and evolutionary relationships among these plants. Possession of the same basic chromosome number, regular meiotic pairing, a high degree of stainable pollen, and good seed set in most of the plants studied indicate possible success in making hybrids for a genetic study of photosynthetic pathways in Panicum.

Journal Article↗
PubMed2005

Species status and phylogeography of two closely related Coptolabrus species (Coleoptera: Carabidae) in South Korea inferred from mitochondrial and nuclear gene sequences.

We investigated the species status and intraspecific phylogeography in South Korea of two ground beetle species, Coptolabrus jankowskii and Coptolabrus smaragdinus (Coleoptera: Carabidae), using statistical parsimony networks and nested clade analyses based on sequences from the mitochondrial cytochrome oxidase subunit I (COI) and nuclear phosphoenolpyruvate carboxykinase (PepCK) and wingless (Wg) genes. Although traditional parsimony tree construction generally failed to resolve interspecific relationships and construct biologically meaningful genealogies, analysis using statistical parsimony networks yielded statistically significant inter- and intraspecific genealogical structures. We found that although these two species represent a notable case of trans-species polymorphisms in both mitochondrial and nuclear gene sequences, their status as separate species was evidenced by the nonrandom association between species and nested clades at various nesting levels. The exceptional occurrence of shared identical or very similar COI sequences was considered to be the result of introgressive hybridization. In addition, range expansion and fragmentation events across the Korean Peninsula and adjacent islands were inferred from nested clade phylogeographical analyses. The COI gene revealed the geographical divergence of major eastern and western clades and historical biogeographical events within each major clade, whereas the nuclear PepCK gene, which did not reveal corresponding east-west clades, indicated past fragmentation and range expansion across wide areas that may have been the result of older biogeographical events. Thus, phylogeographical inferences drawn from analyses of mitochondrial and nuclear genes can reveal different and potentially complementary information about phylogeographical processes.

Animals↗
PubMed2006

Niche breadth, competitive strength and range size of tree species: a trade-off based framework to understand species distribution.

Understanding the mechanisms causing latitudinal gradients in species richness and species range size is a central issue in ecology, particularly in the current context of global climate change. Different hypotheses have been put forward to explain these patterns, emphasizing climatic variability, energy availability and competition. Here we show, using a comparative analysis controlling for phylogeny on 234 temperate/boreal tree species, that these hypotheses can be included into a single framework in an attempt to explain latitudinal gradients in species range size. We find that species tend to have larger ranges when (i) closer to the poles, (ii) successionally seral, (iii) having small and light seeds, and (iv) having short generations. The patterns can simply be explained by energy constraints associated with different life-history strategies. Overall, these findings shed a new light on our understanding of species distribution and biodiversity patterns, bringing new insights into underlying large-scale evolutionary processes.

Ecosystem↗
PubMed2003

[Atopic dermatitis and Malassezia species: a study of antigenic components of Malassezia species for immunoglobulin E of patients with atopic dermatitis].

Antigenic components extracted by treatment with beta-mercaptoethanol from M. furfur, M. globosa, M. restricta, M. slooffiae, and M. sympodialis were studied for immunoglobulin E antibodies in sera of patients with atopic dermatitis. CBB staining and lectin blots of the extracts showed that each Malassezia species contained species-dependent components at the protein level. In a Western blot with the 2-ME extracts,IgE antibodies against the Malassezia species were found in sera of 83% (for M. globosa), 74% (for M. sympodialis), 65% (for M. furfur), 56% (for M. restricta) and 50% (for M. slooffiae) of the AD patients. In the Western blot inhibition test, the 2-ME extract of M. globosa partially inhibited the reaction of the antigenic components of other Malassezia species with the patients IgE antibodies. These results indicated that Malassezia species contained both species-specific and common antigenic components at the IgE antibody level. A major component of M. globosa was isolated from the 2-ME extract of this fungus by ion-exchange column chromatography and was referred to as Malg46b. Dot blot with the Malg46b containing fraction immunologically reacted with 69% of the sera of the patients, and with 83% of the sera of those who were positive for IgE antibodies to the 2-ME extract of M. globosa in Western blot. The intensities generated for each dot correlated well with the total intensities generated for the 2-ME extract of M. globosa in Western blot (r=0.763) The polyclonal antibody to Malg46b reacted strongly only with the 2-ME extract of M. globosa and reacted slightly with M. restricta. These results indicate that a glycoprotein, Malg46b of M. globosa, is dominantly expressed in this fungus and is a possible major antigen for IgE antibodies in patients with AD.

Antibodies, Fungal↗
PubMed1989

Identification of species D, a new member of the Anopheles quadrimaculatus species complex: a biochemical key.

Sibling species D, a new member of the Anopheles quadrimaculatus species complex was identified in collections from Pickwick Lake, Tishomingo County, Mississippi and Choctawhatchee, Bay County, in West Florida. This species occurred sympatrically with the previously described species, A, B and C. Evidence for identification of species D includes diagnostic allozymes, a lack of polytene chromosomes in the ovarian nurse cells, and inviability of F1 progeny and lack of sperm transfer in hybridization crosses. An electrophoretic taxonomic key for distinguishing species D from A, B and C is presented.

Animals↗
PubMedDate not supplied

Species differences in the generation of reactive oxygen species by microglia.

Although a variety of potential sources for reactive oxygen species (ROS) exist in the CNS, brain macrophages, i.e., the microglia, generate large quantities of these reactive species, particularly in response to injury or inflammatory signals. In order to understand how microglia contribute to changes in oxidative status of the CNS and how this might related to disease states, such as Alzheimer disease (AD), we have examined the regulation of superoxide anion and nitric oxide production from rodent and human microglia. Our results indicate that microglia from all species we have studied release superoxide anion, but produce significantly different amounts in response to the same activating agents. Species differences are also found in the ability to generate nitric oxide (NO). In particular, mouse microglia generate large quantities of NO when stimulated, but human and hamster microglia do not produce measurable amounts under the same stimulation conditions. These species differences are important to consider when modeling human disease processes from rodent studies.

Animals↗
PubMed1993

Species scaling of propafenone disposition and concentration--time relationships among eight mammalian species.

Usually, smaller mammals have higher clearances per unit body mass than do larger mammalian species. When clearance and other pharmacokinetic parameters are correlated with internal physiological processes, species tend to dispose of drugs at a similar pace. The first application of this concept is pharmacokinetic time, expressed with different units: Kallynochron, Apolysichron, Dienetichron, and Syndesichron. The present work describes pharmacokinetic time in these units from data obtained with propafenone in eight animal species: mouse, rat, rabbit, dog, sheep, human, cow, and horse. Additionally, volume of distribution (Vdss = 6.5 B0.94) and clearance (CL = 0.17 B0.86) were correlated to body weight (B). Different units of pharmacokinetic time were evaluated with an Akaike Information Criterion test, and the Syndesichron was the unit that provided the best superimposition for the concentration-time plot for all animal species. It can be inferred that all mammalian species eliminated half of the dose from their bodies in 4759 Syndesichrons.

Adult↗
PubMed2006

Cloned endangered species takin (Budorcas taxicolor) by inter-species nuclear transfer and comparison of the blastocyst development with yak (Bos grunniens) and bovine.

Interspecies cloning might be used as an effective method to conserve endangered species and to support the study of nuclear-cytoplasm interaction. In this study, we describe the development of takin-bovine embryos in vitro produced by fusing takin ear fibroblasts with enucleated bovine oocytes and examine the fate of mitochondrial DNA in these embryos. We also compare the blastocyst development of takin-bovine embryos with yak-bovine and bovine-bovine embryos and compare the cell numbers of the blastocyst. Our results indicate that: (1) takin-bovine cloned embryos can develop to the blastocyst stage in vitro (5%), (2) blastocyst mitochondria DNA are derived primarily from bovine oocytes in spite of a little takin donor cell mitochondrial DNA, (3) using the same cloned protocol, development efficiency is significantly different between bovine-bovine cloning, yak-bovine, and takin-bovine cloning (48 vs. 28% vs. 5%, P < 0.01), and (4) cell numbers in the blastocysts of the three species of embryos were not different. These results suggest that the bovine oocytes can reprogram the takin, yak, and bovine fibroblast nuclei. However, the development efficiency of intra-species cloning tends to be higher than inter-species cloning; the more close the species of the donor cell is to the recipient oocyte (yak versus takin), the greater the blastocyst development in vitro.

Amino Acid Sequence↗
PubMed1993

Factors affecting the species-homologous and species-heterologous binding of mitochondrial ATPase inhibitor, IF1, to the mitochondrial ATPase of slow and fast heart-rate hearts.

We examined the effects of a variety of conditions upon the IF1-mediated inhibition of the ATPase in both intact and sonicated mitochondria and in IF1-depleted submitochondrial particles (SMP) in species-homologous and species-heterologous combinations of IF1 and ATPase. IF1-mediated ATPase inhibition occurred in intact rabbit heart mitochondria at low matrix pH and low membrane potential, but not in intact pigeon and rat heart mitochondria under the same conditions. IF1-mediated ATPase inhibition was, however, demonstrable in both the rabbit and pigeon heart systems in sonicated mitochondria incubated at low ionic strength. The rat heart system failed to exhibit significant IF1-mediated ATPase inhibition in either intact or sonicated mitochondria due to the low amount of IF1 present. When rabbit heart IF1-containing extracts were incubated with IF1-depleted rabbit heart SMP over a range of KCl concentrations, increasing the [KCl] to 100 mM had little effect on IF1-mediated ATPase inhibition. When pigeon heart IF1-containing extracts were incubated with IF1-depleted pigeon heart SMP under the same conditions, increasing [KCl] to 100 mM nearly completely blocked IF1-mediated ATPase inhibition. While the species-endogenous level of rat heart IF1 (i.e., 1x IF1) inhibited IF1-depleted rat heart SMP virtually not at all at any [KCl] examined, the 8x rat heart IF1 was nearly as inhibitory as the 1x rabbit heart IF1 at varying ionic strengths. When rabbit, pigeon, or rat heart IF1 was bound to rabbit versus pigeon IF1-depleted SMP, the effect of varying ionic strength on IF1-mediated ATPase inhibition was related to the species source of the IF1, not to the species source of the enzyme; 1x bovine heart IF1 purified to homogeneity behaved much like 1x crude rabbit heart IF1 when binding to either the rabbit or the pigeon heart enzyme. This suggests that an IF1-ATPase complex stabilizing factor such as has been isolated from baker's yeast cells in neither lacking in the pigeon heart system nor required for the more ionic-strength-resistant binding of IF1 observed in slow heart-rate mammalian heart mitochondria.

Adenosine Triphosphatases↗