Biomedical subjects

M D Collins

Publications and source records attributed to M D Collins.

At least 181 records · Page 10Linked to original sources

PubMed1995

Reclassification of Oribaculum catoniae (Moore and Moore 1994) as Porphyromonas catoniae comb. nov. and emendation of the genus Porphyromonas.

A partial 16S rRNA gene sequence of the type strain of Oribaculum catoniae was determined by using PCR direct sequencing. A comparative sequence analysis demonstrated that this species, although saccharolytic, is phylogenetically a member of the genus Porphyromonas. On the basis of the phylogenetic and phenotypic distinctiveness of O. catoniae, we formally propose that this species should be reclassified in the genus Porphyromonas catoniae comb. nov. An emended description of the genus Porphyromonas is presented.

Bacteroidaceae↗

PubMed1995

Phylogenetic analysis of the genus Corynebacterium based on 16S rRNA gene sequences.

The 16S rRNA gene sequences of 30 strains representing 23 validated Corynebacterium species and 7 currently non-valid Corynebacterium species were determined. These sequences were aligned with the sequences of other Corynebacterium species and related actinomycete taxa. A comparative sequence analysis revealed that there is considerable phylogenetic depth and internal structure in the genus Corynebacterium. Turicella otitidis and the amycolate species Corynebacterium amycolatum were located at the periphery of the genus Corynebacterium. It was evident that the species of the genus Corynebacterium form a monophyletic association and, together with other chemotype IV and mycolic acid-containing taxa (including the genera Dietzia, Gordona, Mycobacterium, Nocardia, Rhodococcus, and Tsukamurella), form a natural suprageneric group.

Base Sequence↗

PubMed1995

Heterogeneity within human-derived centers for disease control and prevention (CDC) coryneform group ANF-1-like bacteria and description of Corynebacterium auris sp. nov.

Recently, Centers for Disease Control and Prevention coryneform group ANF-1 bacteria were described as Corynebacterium afermentans, and group ANF-1-like bacteria were described as Turicella otitidis. Over a 1.5-year period 10 strains of a previously undescribed, gram-positive, rod-shaped organism that was not partially acid fast and resembled ANF-1-like bacteria were isolated from different pediatric patients with ear infections. These previously undescribed coryneform bacteria exhibited a distinct colony morphology and consistency, had a carbon source utilization pattern distinct from the carbon source utilization patterns of C. afermentans and T. otitidis, had a cell wall based on meso-diaminopimelic acid, contained mycolic acids, and had DNA G+C contents of 68 to 74 mol%. A 16S rRNA gene sequence analysis revealed that these clinical isolates are members of the genus Corynbacterium and that they are distinct from C. afermentans and T. otitidis. On the basis of phenotypic and phylogenetic evidence we propose a new species, Corynebacterium auris, for these Centers for Disease Control and Prevention coryneform group ANF-1-like bacteria. The type strain is strain DSM 44122 (CCUG 33426).

Actinomycetales↗

PubMed1995

Comparison of 16S rRNA sequences of segmented filamentous bacteria isolated from mice, rats, and chickens and proposal of "Candidatus Arthromitus".

Segmented filamentous bacteria (SFB) are nonpathogenic bacteria that are commonly found attached to the intestinal walls of many animals. Until now, these bacteria have not been cultured in vitro. Recently, a 16S rRNA sequence analysis revealed that SFB isolated from mice represent a distinct subline within the Clostridium subphylum of the gram-positive bacteria. Since SFB isolated from mice, rats, and chickens are known to be host specific, we investigated the phylogenetic relationships among SFB obtained from these three hosts. Total DNAs from the intestinal floras of chickens and rats were used as templates for PCR amplification of 16S rRNA genes. PCR products were cloned and screened by a dot blot hybridization procedure to identify homologous sequences that cross-reacted with mouse SFB-specific oligonucleotide probes. A phylogenetic analysis of these 16S ribosomal DNA sequences revealed that SFB isolated from these three hosts form a natural group, which is peripherally related to the genus Clostridium sensu stricto (group I Clostridium). The SFB obtained from chickens, rats, and mice had closely related, albeit different, 16S rRNA gene sequences. The observed levels of 16S rRNA sequence divergence, ca. 1.5 to 3%, together with host specificity, suggest that SFB isolated from mice, rats, and chickens represent different species and that coevolution of the SFB and their hosts occurred. "Candidatus Arthromitus" is proposed as the provisional generic name for this group of organisms.

Animals↗

PubMed1995

16S rRNA gene similarities indicate that Hallella seregens (Moore and Moore) and Mitsuokella dentalis (Haapsalo et al.) are genealogically highly related and are members of the genus Prevotella: emended description of the genus Prevotella (Shah and Collins) and description of Prevotella dentalis comb. nov.

Because of similarities in the cellular fatty acid compositions of Hallella seregens and Mitsuokella dentalis, we determined the 16S rRNA gene sequences of the type strains of these species to assess their relationship. A very high level of sequence relatedness (approximately 99.8%) was found between H. seregens and M. dentalis, indicating that these species are genealogically closely related. A comparative sequence analysis revealed that these two species are members of the genus Prevotella and are phylogenetically remote from Mitsuokella multiacidus (the type species of the genus Mitsuokella), which was found to be a member of the Sporomusa subbranch of the Clostridium subphylum of the gram-positive bacteria. On the basis of our phylogenetic findings, we propose that M. dentalis should be reclassified as Prevotella dentalis comb. nov.

Base Sequence↗

PubMed1995

Evidence for the placement of the gram-negative Catonella morbi (Moore and Moore) and Johnsonella ignava (Moore and Moore) within the Clostridium subphylum of the gram-positive bacteria on the basis of 16S rRNA sequences.

Comparative 16S rRNA analysis was used to determine the phylogenetic positions of Catonella morbi and Johnsonella ignava, which are members of two monospecific genera of gram-negative anaerobic bacilli isolated from human gingival crevices. Both of these genera were found to belong to cluster XIVa (M. D. Collins, P. A. Lawson, A. Willems, J. J. Cordoba, J. Fernandez-Garayzabal, P. Garcia, J. Cai, H. Hippe, and J. A. E. Farrow, Int. J. Syst. Bacteriol. 44:812-826, 1994) of the Clostridium subphylum of gram-positive bacteria. Within this cluster, which contains several Clostridium, Coprococcus, Eubacterium, and Ruminococcus species, C. morbi and J. ignava formed two distinct lines that were separate from all other taxa. Our findings support the separate generic status of the genera Catonella and Johnsonella and show that these genera do not belong to the family Bacteroidaceae but instead belong to the gram-positive Clostridium subphylum.

Base Sequence↗

PubMed1995

Cetobacterium ceti gen. nov., sp. nov., a new gram-negative obligate anaerobe from sea mammals.

Phenotypic and phylogenetic studies were performed on a Gram-negative obligately anaerobic rod-shaped bacterium isolated from two sea mammals. 16S rRNA gene sequence analysis demonstrated the bacterium represents a hitherto unknown line of descent peripherally associated to the fusobacteria and low G+C relatives. Based on the result of the phylogenetic analysis and phenotypic criteria, it is proposed that the bacterium should be assigned to a new genus, Cetobacterium ceti gen. nov., sp. nov. The type strain of Cetobacterium ceti sp. nov. is NCFB 3026.

Animals↗

PubMed1995

Phenotypic and phylogenetic characterization of some unknown coryneform bacteria isolated from bovine blood and milk: description of Sanguibacter gen.nov.

16S rRNA gene sequencing studies were performed on some Gram-positive coryneform bacteria of unknown taxonomic position isolated from blood and milk of healthy cows. Comparative sequence analysis demonstrated that the milk isolates corresponded to Oerskovia xanthineolytica whereas those from blood consisted of two distinct, albeit highly related species, within the family Cellulomonadaceae. Based on the phylogenetic and phenotypic distinctiveness of the blood isolates, it is proposed that they be classified in a new genus Sanguibacter.

Actinomycetales↗

PubMed1995

Assignment of Actinomyces pyogenes-like (CDC coryneform group E) bacteria to the genus Actinomyces as Actinomyces radingae sp. nov. and Actinomyces turicensis sp. nov.

In a previous study the authors reported the characterization of some facultatively anaerobic, Gram-positive, non-sporeforming rods which were found in mixed cultures from various infectious processes, including patients with otitis, empyema, perianal abscesses and decubitus ulcers. Phenotypically these organisms closely resembled Actinomyces pyogenes although their precise taxonomic position remained unknown. In the present investigation the authors have determined the 16S rRNA gene sequences of some representative strains of the Actinomyces pyogenes-like bacteria and report the results of a comparative sequence analysis. On the basis of the results of the present and earlier findings two new Actinomyces species, Actinomyces radingae sp. nov. and Actinomyces turicensis sp. nov. are proposed. The type strains are DSM 9169T and DSM 9168T, respectively.

Actinomyces↗

PubMed1995

Mycobacterium conspicuum sp. nov., a new species isolated from patients with disseminated infections.

A new type of slowly growing, nonphotochromogenic mycobacterium was recovered from two patients with disseminated disease. The growth characteristics, acid fastness, acids were consistent with those for Mycobacterium species. The results of biochemical investigations, lipid analyses, and comparative 16S rRNA sequencing showed that these isolates represent a new slowly growing Mycobacterium species which is named Mycobacterium conspicuum.

Adult↗

PubMed1995

Identification of some clinical strains of CDC coryneform group A-3 and A-4 bacteria as Cellulomonas species and proposal of Cellulomonas hominis sp. nov. for some group A-3 strains.

CDC coryneform group A-3 and A-4 bacteria were defined by Hollis and Weaver in 1981, but their taxonomic position is still unclear. By using biochemical and chemotaxonomical methods, four clinical strains belonging to CDC coryneform groups A-3 (n = 2) and A-4 (n = 2) were studied and could be assigned to the genus Cellulomonas, resulting in the first description of Cellulomonas strains isolated from clinical specimens. CDC coryneform group A-3 and A-4 strains were compared with the type strains of the seven species constituting the genus Cellulomonas at present as well as with the closely related species Oerskovia turbata, Oerskovia xanthineolytica, and Jonesia denitrificans, but their biochemical patterns were not compatible with the patterns of any of those species. Almost the entire sequences of the 16S rRNA genes of one representative strain of both CDC taxa were determined, and comparative sequence analysis confirmed the placement of the CDC coryneform group A-3 and A-4 strains studied in the Cellulomonas-Oerskovia subbranch of the actinomycetes. Both CDC taxa exhibited > 99% base pair homology within their 16S rDNAs. On the basis of phenotypic and molecular data, we formally propose a new species, Cellulomonas hominis sp. nov., for the CDC coryneform group A-3 bacteria examined. The type strain is DSM 9581. The precise taxonomic status of the CDC coryneform group A-4 strains studied remains to be established by quantitative DNA-DNA hybridizations.

Actinomycetales↗

PubMed1995

Bacillus oleronius sp.nov., a member of the hindgut flora of the termite Reticulitermes santonensis (Feytaud).

A new rod-shaped endospore-forming bacterium is described, which was isolated from the hindgut of the termite Reticulitermes santonensis (Feytaud). The isolate stains Gram negative and its DNA has a guanine-plus-cytosine content of 35 mol%. Despite the Gram-staining reaction, both biochemical and physiological features place the isolate in the genus Bacillus and indicate a phenotypic resemblance to the Bacillus firmus-lentus group of species. On the basis of comparative 16S rRNA analysis and some phenotypic features the isolate clearly represents a new species for which the name Bacillus oleronius is proposed. The type strain is Bacillus oleronius Rt 10 (DSM 9356).

Animals↗

PubMed1994

Identification of a 100-kDa phosphoprotein in developing murine embryos as elongation factor 2.

Protein phosphorylation is a key regulatory mechanism for several functions. Although the complex control of organogenesis and growth most likely includes such mechanisms, few reports have examined protein phosphorylation in the developing mammal. The identification and characterization of mammalian embryonic phosphoproteins will allow a greater understanding of the regulation and mechanisms of developmental processes. Phosphorylation of the endogenous mouse proteins during development revealed a 100-kDa protein, located in the cytosolic fraction, to be the major substrate. The Ca(2+)-calmodulin kinase inhibitors, trifluorperazine and ethylene glycol bis(beta-aminoethyl ether)N,N'-tetraacetic acid, inhibited this phosphorylation. Inhibitors of protein kinase C (H-7)- and cAMP-dependent protein kinase, as well as the tyrosine kinase inhibitor, genistein, had no effect. One- and two-dimensional phosphoamino acid analysis indicated that phosphothreonine was the major phosphorylated amino acid. To determine the identity of this protein, the 100-kDa band was isolated and submitted for amino acid analysis and N-terminal sequencing. The N-terminal sequence Val-Asn-Phe-Thr-Val-Asp-Gln-Ile-Arg-Ala-Ile-Met-Asp-Lys, was identical to the N-terminal sequence of human, hamster and rat elongation factor 2 (EF-2). Western blotting analysis confirmed that the 100 kDa protein was EF-2. Our results of phosphorylated EF-2 in the developing mouse are in agreement with those reported in the avian embryo. However, our results differ in that phosphotyrosine detected in avian embryos could not be detected in murine embryos. This is the first report to demonstrate EF-2 in the developing mammalian embryo and its specific phosphorylation pattern. Our data suggest that the functional phosphoregulation of elongation factor 2 during protein synthesis in mammals is conserved from the developing embryo to the adult and thus emphasizes the importance of EF-2 in normal development and survival.

Amino Acid Sequence↗

PubMed1994

Neurologic sequelae secondary to atlantoaxial instability in Down syndrome. Implications in otolaryngologic surgery.

OBJECTIVE: A comprehensive overview of atlantoaxial instability in Down syndrome as it relates to head and neck surgery and recommendations as derived from a review of the literature. DATA SOURCES: English-language literature: otolaryngologic problems in Down syndrome and atlantoaxial biomechanics. DATA SYNTHESIS: Children affected with Down syndrome frequently require otolaryngologic procedures such as myringotomy with ventilation tubes or adenotonsillar surgery. Atlantoaxial instability occurs in 10% to 20% of patients with Down syndrome who are at risk for atlantoaxial subluxation and subsequent complications during anesthetic induction and during positioning and manipulation associated with surgery. To identify patients who are at risk for atlantoaxial subluxation, guidelines have been adapted from the recommendations of the American Academy of Pediatrics and the Special Olympics Inc, which include preoperative neurologic assessments and cervical roentgenograms in the neutral, flexion, and extension positions. Children with an atlantodental interval of greater than 4.5 mm or with peripheral neurologic findings should have further evaluation. CONCLUSIONS: A small percentage of patients with Down syndrome are at risk for atlantoaxial instability and subluxation. All patients with Down syndrome should have a preoperative neurologic assessment screening by the operating surgeon and/or a cervical roentgenogram in the lateral, extension, and flexion positions. Any abnormality should be investigated before surgery.

Anesthesia, Inhalation↗

PubMed1994

Genetic interrelationship among species of the genus Zygosaccharomyces as revealed by small-subunit rRNA gene sequences.

The phylogenetic interrelationship of species of the genus Zygosaccharomyces was examined by 18S rRNA gene sequencing. Comparative analysis of the sequence data revealed the genus to consist of a number of distinct subdivisions. The most prevalent species associated with food spoilage, Z. bailii, Z. bisporus and Z. rouxii, along with Z. mellis were found to form one subdivision. Zygosaccharomyces cidri and Z. fermentati formed a distinct species pair, as did Z. microellipsoides and Z. mrakii. Zygosaccharomyces florentinus formed a separate line displaying no specific relationship with any of the other Zygosaccharomyces species examined. Comparison with nine published ascosporogenous yeast 18S rRNA gene sequences showed that Z. microellipsoides and Z. mrakii were genealogically very close to Torulaspora delbrueckii (both displaying 99.8% 18S rRNA sequence similarity), raising the possibility that these two Zygosaccharomyces species should be moved to the genus Torulaspora. The topologies of trees derived from complete 18S rRNA gene sequences and from individual domains within the gene were compared and the implications of using partial sequence data for inferring phylogenetic relationships discussed.

Base Sequence↗

PubMed1994

Enhanced expression of limb malformations and axial skeleton alterations in legless mutants by transplacental exposure to retinoic acid.

This manuscript reports on the limb malformations and axial skeleton alterations found in legless fetuses and their heterozygote and wild-type littermates transplacentally exposed to all-trans-retinoic acid via a single intraperitoneal injection on Day 7, 8, 9, 9.5, 10, 10.5, or 11 of gestation. The most surprising aspect of the results was the temporal sensitivity of the legless mouse limb to exogenous retinoic acid. On Day 11, when both fore- and hindlimbs of nonmutant embryos can be made abnormal by retinoic acid and other teratogens, retinoic acid did not increase the frequency or severity of legless hindlimb defects and forelimb malformations were only slightly enhanced. On the other hand, retinoic acid administration on Day 7 exacerbated forelimb malformations in legless fetuses at a time when visible emergence of the affected structure is still 48 hr away. Heterozygote and wild-type fetuses had no limb malformations at this time point. A similar phenomenon was observed with hindlimb malformations after retinoic acid exposure on Day 8 except for a few mild limb malformations in heterozygotes at a high dose of retinoic acid. This early hypersensitivity of fore- and hindlimbs was followed by a period of reduced sensitivity (Day 8 forelimb; Day 9 hindlimb) when even very high doses (50 mg/kg) induced minimal changes in the typical legless malformation pattern. Subsequently, at the time of visible limb bud emergence (Day 9 forelimbs; Day 10 hindlimbs), sensitivity to exogenous retinoic acid was again detected. Surprisingly, the altered malformation patterns induced by retinoic acid in lgl mutants were nearly identical to those from earlier, pre-emergence exposure. A number of axial skeleton alterations were induced in legless fetuses by retinoic acid, especially after exposure on Days 7, 8, or 9. Posterior truncations were particularly noteworthy, showing a graded response in which frequency and severity of truncation were worst in lgl/lgl fetuses; heterozygotes gave an intermediate response, and wild-type fetuses were least affected. This exacerbation of the legless phenotype by exogenous retinoic acid coupled with the similarity between legless and retinoid malformations suggest that the legless mutation has altered endogenous retinoid homeostasis or a downstream retinoid-responsive gene.

Abnormalities, Drug-Induced↗

PubMed1994

Endogenous status of retinoids and their cytosolic binding proteins in limb buds of chick vs mouse embryos.

The morphogenetic role of all-trans-retinoic acid (RA) during limb development, especially its activity in directing anterior/posterior pattern formation remains controversial. We have measured retinoids and cytosolic binding proteins in anterior and posterior pieces of limb buds from comparably aged chick and mouse embryos expecting that localization patterns of morphological significance will be evident across species. Many species differences were found including: (1) nondetectable 3,4-didehydroretinoic acid (ddRA) in mouse limb buds, the predominant morphogenetically active retinoid in chick limbs; the precursor of ddRA, 3,4-didehydroretinol (ddROH), was also not present in mouse limb buds but found in high concentration in chick limb buds; (2) a higher concentration of morphogenetically active retinoid (RA + ddRA) in chick compared to mouse limb buds; (3) a high level of retinyl esters (1.5 microM) in chick limb bud, but undetectable concentration in mouse limb buds; and (4) a higher level of cytosolic retinoic acid binding proteins (CRABPs) in chick limb buds, especially CRABP II, which is 10X greater than in mouse limb buds. An interesting finding seen in mouse and chick limb buds was a disparity between the concentration of ligand and cytosolic binding protein. Retinol (ROH) and ddROH were present in much higher concentrations than cytosolic retinol binding protein (CRBP). Conversely, RA and ddRA were in far lower concentration than CRABPs. Any morphological significance of these disparities is unknown. A putative gradient of RA, high posteriorly, was found in chick limb buds as in earlier studies (Thaller and Eichele, 1987), but the magnitude of this gradient was less than previously reported. We also found ddRA in equal concentration in the anterior and posterior pieces of chick limb bud studied here, further weakening the idea of an RA gradient as the direct force in anterior/posterior pattern formation. The "free" concentration of retinoic acid, calculated from ligand and binding protein concentration and affinity, was slightly higher in posterior chick limb tissue (2.0X) and in mouse limb buds at a concentration similar to the Kd of murine nuclear retinoic acid receptors.

Animals↗

PubMed1994

Comparative teratology and transplacental pharmacokinetics of all-trans-retinoic acid, 13-cis-retinoic acid, and retinyl palmitate following daily administrations in rats.

The retinoids are teratogenic in a wide variety of species. In the rat, 13-cis-retinoic acid and retinyl palmitate are significantly less potent teratogens than all-trans-retinoic acid. This investigation questioned whether differing teratogenic potencies of these moieties can be correlated with the concentrations of these drugs and/or metabolites in the embryonic compartment. Approximately equipotent teratogenic doses of these three retinoids were administered and the pharmacokinetics in maternal plasma and embryo of the most prevalent vitamin A metabolites were measured. The glucuronides of the respective retinoids were the predominant metabolites in the maternal plasma, but were not detected in the embryo. Also, the transport of 13-cis-retinoic acid across the placenta occurred to a much lesser extent than the transport of all-trans-retinoic acid. Administration of either all-trans- or 13-cis-retinoic acid causes a depression in the endogenous retinol concentration. This depression is more pronounced in the maternal plasma than in the embryo. The depression of the retinol level in both plasma and embryo after 13-cis-retinoic acid administration (75 mg/kg/day) was greater than the depression after all-trans-retinoic acid (6 mg/kg/day), corroborating the inferential teratological data that the 13-cis-retinoic acid dose was more embryotoxic than the all-trans-retinoic acid dose. Although the dose of all-trans-retinoic acid was less embryotoxic than that of either 13-cis-retinoic acid or retinyl palmitate, the embryonic exposure to all-trans-retinoic acid was considerably larger, as determined by maximum concentration or area under the concentration-versus-time curve, after administration of all-trans-retinoic acid than after either retinyl palmitate or 13-cis-retinoic acid application. These results suggest that embryonic retinoids other than all-trans-retinoic acid--including the administered substances themselves--are important in the teratogenic process induced by 13-cis-retinoic acid and retinyl palmitate.

Animals↗