scholarly journals Commensal Streptococcus mitis produces two different lipoteichoic acids of type I and type IV

2021 ◽  
Author(s):  
Nicolas Gisch ◽  
Katharina Peters ◽  
Simone Thomsen ◽  
Waldemar Vollmer ◽  
Dominik Schwudke ◽  
...  
Keyword(s):  
Lipoteichoic Acid ◽  
Opportunistic Pathogen ◽  
Type I ◽  
Beta Lactam ◽  
Viridans Streptococci ◽  
Glycerol Phosphate ◽  
Streptococcus Mitis ◽  
Antibiotic Resistant ◽  
Type Iv ◽  
High Level

The opportunistic pathogen Streptococcus mitis possesses, like other members of the Mitis group of viridans streptococci, phosphorylcholine (P-Cho)-containing teichoic acids (TAs) in its cell wall. Bioinformatic analyses predicted the presence of TAs that are almost identical with those identified in the pathogen S. pneumoniae, but a detailed analysis of S. mitis lipoteichoic acid (LTA) was not performed to date. Here we determined the structures of LTA from two S. mitis strains, the high-level beta-lactam and multiple antibiotic resistant strain B6 and the penicillin-sensitive strain NCTC10712. In agreement with bioinformatic predictions we found that the structure of one LTA (type IV) was like pneumococcal LTA, except the exchange of a glucose moiety with a galactose within the repeating units. Further genome comparisons suggested that the majority of S. mitis strains should contain the same type IV LTA as S. pneumoniae, providing a more complete understanding of the biosynthesis of these P-Cho-containing TAs in members of the Mitis group of streptococci. Remarkably, we observed besides type IV LTA an additional polymer belonging to LTA type I in both investigated S. mitis strains. This LTA consists of β-galactofuranosyl-(1,3)-diacylglycerol as glycolipid anchor and a poly-glycerol-phosphate chain at the O-6 position of the furanosidic galactose. Hence, these bacteria are capable of synthesizing two different LTA polymers, most likely produced by distinct biosynthesis pathways. Our bioinformatics analysis revealed the prevalence of the LTA synthase LtaS, most probably responsible for the second LTA version (type I), amongst S. mitis and S. pseudopneumoniae strains.

Canadian national survey of prevalence of antimicrobial resistance among clinical isolates of Streptococcus pneumoniae. Canadian Bacterial Surveillance Network.

1996 ◽  
Vol 40 (9) ◽  
pp. 2190-2193 ◽  
Author(s):  
A E Simor ◽  
M Louie ◽  
D E Low
Keyword(s):  
Streptococcus Pneumoniae ◽  
Antimicrobial Agents ◽  
Clinical Isolates ◽  
Beta Lactam ◽  
Surveillance Network ◽  
Antibiotic Resistant ◽  
Intermediate Resistance ◽  
Resistant Strains ◽  
High Level ◽  
Level Resistance

The antimicrobial susceptibilities of 1,089 clinical isolates of Streptococcus pneumoniae obtained from 39 laboratories across Canada between October 1994 and August 1995 were determined. A total of 91 isolates (8.4%) demonstrated intermediate resistance (MIC, 0.1 to 1.0 microgram/ml) and 36 (3.3%) had high-level resistance (MIC, > or = 2.0 micrograms/ml) to penicillin. Penicillin-resistant strains were more likely to have been recovered from normally sterile sites (P = 0.005) and to be cross-resistant to several beta-lactam and non-beta-lactam antimicrobial agents (P < 0.05). These results indicate that there has been a recent significant increase in the prevalence of antibiotic-resistant S. pneumoniae in Canada.

Morbidity of aging non-incubated chicken blastoderms: further cytological evidence and interpretation

Development ◽  
1974 ◽  
Vol 32 (3) ◽  
pp. 557-571
Author(s):  
T. Konishi ◽  
I. L. Kosin
Keyword(s):  
Mitotic Activity ◽  
Type I ◽  
Metaphase Chromosomes ◽  
Interphase Nuclei ◽  
Cytological Evidence ◽  
Storage Chamber ◽  
Type Iv ◽  
Plastic Bags ◽  
Cytological Picture ◽  
High Level

Cytological analysis was carried out on the blastodermal cells of White Leghorn eggs ubjected to several pre-incubation treatments. These treatments were storage, ranging from0 days to 4 weeks, together with one or more of the following: (1) variation of ambient temperature (5 °C, 15·5 °C, 24 °C), (2) variation of carbon dioxide level (normal air, 1·5% CO2-enriched air), (3) increased humidity (wrapping in plastic bags). To facilitate analysis, the chromosomal configuration of metaphase cells was classified into four types, I–IV, according to their increasingly ‘abnormal’ appearance, which included condensation, dispersal and/or clumping of chromosomes. In interphase cells, the degree of ‘abnormality’ was rated on the staining capacity and shape of the nuclei. The study yielded the following results. (1) Temperature of storage was the most important single factor determining the state of ‘normality’ of the nuclei. The CO2 level in the storage chamber or the use of plastic bags (toprovide the eggs in storage with a special‘ mini-environment’, believed largely due to increased humidity) had little effect on the cytological picture of the affected blastoderms. (2) As the blastoderms of eggs stored at 15·5 °C aged, the proportion of Type IV chromosomal configurations steadily rose. At 24 °C the aging process frequently followed a different route: both metaphase and post-metaphase chromosomes often simply disintegrated; the progression from Type I to Type IV was not in evidence. Aging at 5 °C resulted in an early appearance of uniformly dark-stained, spherical or oval nuclei. These were similar to those observed in the terminal stages of retrogression seen in the interphase nuclei. (3) During extended storage at 15·5 °C, mitosis was shown to be blocked at metaphase. No active mitoses were observed in the blastoderms of eggs stored at 5 °C. At 24 °C however, limited mitotic activity was present, up to and including anaphase. (4) The presence or absence of a high level of mitotic activity during pre-incubation storage was not crucial to the survival of the blastoderm. However, an environment that permitted limited mitosis was important if the cells were to have the best possible chancefor remaining alive during storage. The CO2 content of the air or the use of plastic bags played no role in this respect. (5) Two explanations, at the nuclear level, are suggested for the observed chain of events in the blastoderm of a stored chicken egg.

Genetic control of the nuda character complex in the genus Avena

1976 ◽  
Vol 86 (2) ◽  
pp. 329-334 ◽  
Author(s):  
H. S. Atiyya ◽  
Watkin Williams
Keyword(s):  
Gene Action ◽  
Major Gene ◽  
Type I ◽  
Loss Of Function ◽  
Type Iv ◽  
Avena Nuda ◽  
Type Gene ◽  
Inhibitor Type ◽  
High Level ◽  
Heterozygous Phenotype

SummaryThe inheritance of the units of the character complex which differentiates Avena nuda from Avena sativa was studied in F1 hybrids and in the F2 generation derived from inter-crossing five cultivars of A. saliva with four cultivars of A. nuda. The 14 derived F1 hybrids could be classified into four types depending on the level of dominance of the sativa or nuda character expression. Type-I hybrids involving the cultivar Milford as parent showed a high level of dominance of the sativa-type expression, whereas the F1 hybrid from the cross, Condor × China, type IV, had the character expression typical of the A. nuda parent. Segregation in the F2 generation indicated that the entire character complex was under the control of a major gene, and supported the suggestion from previous work that modifying genes interact with the major gene to alter the expression of the homozygous nuda genotype towards the heterozygous phenotypeHomozygous nuda and heterozygous genotypes were shown to exhibit a gradient in the expression of the nuda character complex from the apex to the base of the panicle, the nuda-type characters being most pronounced in the apical spikelets. It is suggested that the variation of character expression within single panicles of homozygous nuda and heterozygous genotypes indicates the operation of an inhibitor-type gene action rather than a mutation to loss of function.

Altered response of progeria fibroblasts to epidermal growth factor

1991 ◽  
Vol 100 (3) ◽  
pp. 649-655
Author(s):  
A. Colige ◽  
B. Nusgens ◽  
C.M. Lapiere
Keyword(s):  
Growth Factor ◽  
Collagen Synthesis ◽  
Type Iv Collagen ◽  
Accelerated Aging ◽  
High Serum ◽  
Population Doubling ◽  
Type I ◽  
Type Iv ◽  
Potent Growth ◽  
High Level

The Hutchinson-Gilford syndrome (progeria) is a rare disorder in childhood characterized by premature and accelerated aging. This study reports the effect of a potent growth factor, EGF, on the proliferative capacities and extracellular matrix macromolecules and collagenase expression of two strains of progeria skin-derived cells. At low population doubling levels (PDL less than 10), confluent cultures of progeria fibroblasts made quiescent by lowering the concentration of serum in the medium did not respond to EGF while the mitotic activity of normal PDL-matched fibroblasts was almost maximally restored upon addition of EGF. No obvious difference between normal and low PDL progeria fibroblasts was observed in the number and in the affinity of the receptors measured by [125I]EGF binding. The synthesis of collagen and non-collagen proteins was similar in normal and affected cells at low and high serum concentration and both types of cells responded to EGF by a specific inhibition of collagen synthesis. Besides a normal level of mRNA coding for type I and type III collagens, collagenase and laminin, progeria fibroblasts expressed a high level of elastin and type IV collagen mRNA. Like normal fibroblasts, progeria cells responded to EGF by a decrease in the level of mRNA for fibrillar collagens and elastin. In contrast, a complete lack of response to EGF was observed for collagenase mRNA whereas the expression of this enzyme was strikingly induced by EGF in normal PDL-matched cells. The abnormal expression of type IV collagen was not significantly modified by EGF. At PDL greater than 10, progeria cells exhibited features of senescence. A significant reduction of collagen synthesis was observed and no further inhibition by EGF was recorded.

scholarly journals Alanylated lipoteichoic acid primer in Bacillus subtilis

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 155 ◽  
Author(s):  
Yu Luo
Keyword(s):  
Bacillus Subtilis ◽  
Lipoteichoic Acid ◽  
Head Group ◽  
Host Immune System ◽  
Type I ◽  
Bacterial Survival ◽  
Gram Positive Bacteria ◽  
Type Iv ◽  
Glycolipid Anchor ◽  
Group D

Lipoteichoic acid is a major lipid-anchored polymer in Gram-positive bacteria such asBacillus subtilis. This polymer typically consists of repeating phosphate-containing units and therefore has a predominant negative charge. The repeating units are attached to a glycolipid anchor which has a diacylglycerol (DAG) moiety attached to a dihexopyranose head group. D-alanylation is known as the major modification of type I and type IV lipoteichoic acids, which partially neutralizes the polymer and plays important roles in bacterial survival and resistance to the host immune system. The biosynthesis pathways of the glycolipid anchor and lipoteichoic acid have been fully characterized. However, the exact mechanism of D-alanyl transfer from the cytosol to cell surface lipoteichoic acid remains unclear. Here I report the use of mass spectrometry in the identification of possible intermediate species in the biosynthesis and D-alanylation of lipoteichoic acid: the glycolipid anchor, nascent lipoteichoic acid primer with one phosphoglycerol unit, as well as mono- and di-alanylated forms of the lipoteichoic acid primer. Monitoring these species as well as the recently reported D-alanyl-phosphatidyl glycerol should aid in shedding light on the mechanism of the D-alanylation pathway of lipoteichoic acid.

scholarly journals Draft Genome Sequences of Two Streptococcus pneumoniae Serotype 19A Sequence Type 226 Clinical Isolates from Hungary, Hu17 with High-Level Beta-Lactam Resistance and Hu15 of a Penicillin-Sensitive Phenotype

2017 ◽  
Vol 5 (20) ◽  
Author(s):  
Martin Rieger ◽  
Dalia Denapaite ◽  
Reinhold Brückner ◽  
Patrick Maurer ◽  
Regine Hakenbeck
Keyword(s):  
Streptococcus Pneumoniae ◽  
Resistant Strain ◽  
Draft Genome ◽  
Sequence Type ◽  
Beta Lactam ◽  
Genome Sequences ◽  
Antibiotic Resistant ◽  
Content Type ◽  
Single Locus Variant ◽  
High Level

ABSTRACT The draft genome sequences of two multiple-antibiotic-resistant Streptococcus pneumoniae isolates from Hungary, Hu15 and Hu17, are reported here. Strain Hu15 is penicillin susceptible, whereas Hu17 is a high-level-penicillin-resistant strain. Both isolates belong to the serotype 19A sequence type 226, a single-locus variant (in the ddl locus) of the Hungary19A-6 clone.

scholarly journals Streptococcus pneumoniae, S. mitis, and S. oralis produce a phosphatidylglycerol-dependent, ltaS-independent glycerophosphate-linked glycolipid

2020 ◽  
Author(s):  
Yahan Wei ◽  
Luke R. Joyce ◽  
Ashley M. Wall ◽  
Ziqiang Guan ◽  
Kelli L. Palmer
Keyword(s):  
Streptococcus Pneumoniae ◽  
Lipoteichoic Acid ◽  
Growth Defect ◽  
Type I ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Type Iv ◽  
Biosynthetic Precursor ◽  
Increased Sensitivity ◽  
Host Microbe Interactions

AbstractLipoteichoic acid (LTA) is a cell surface polymer of Gram-positive bacteria. LTA participates in host-microbe interactions including modulation of host immune reactions. It was previously reported that the major human pathogen Streptococcus pneumoniae and the closely related oral commensals S. mitis and S. oralis produce Type IV LTAs. Herein, using liquid chromatography/mass spectrometry (LC/MS)-based lipidomic analysis, we found that in addition to Type IV LTA biosynthetic precursors, S. mitis, S. oralis, and S. pneumoniae also produce glycerophosphate (Gro-P)-linked dihexosyl-diacylglycerol (DAG), which is a biosynthetic precursor of Type I LTA. Mutants in cdsA and pgsA produce dihexosyl-DAG but lack (Gro-P)-dihexosyl-DAG, indicating that the Gro-P moiety is derived from phosphatidylglycerol (PG), whose biosynthesis requires these genes. S. mitis, but neither S. pneumoniae nor S. oralis, encodes an ortholog of the PG-dependent Type I LTA synthase, ltaS. By heterologous expression analyses, we confirmed that S. mitis ltaS confers poly-(Gro-P) synthesis in both Escherichia coli and Staphylococcus aureus, and that S. mitis ltaS can rescue the severe growth defect of a S. aureus ltaS mutant. However, despite these observations, we do not detect a poly-(Gro-P) polymer in S. mitis using an anti-Type I LTA antibody. Moreover, (Gro-P)-linked dihexosyl-DAG is still synthesized by a S. mitis ltaS mutant, demonstrating that S. mitis LtaS does not catalyze the transfer of Gro-P from PG to dihexosyl-DAG. Finally, a S. mitis ltaS mutant has increased sensitivity to human serum, demonstrating that ltaS confers a beneficial but currently undefined function in S. mitis. Overall, our results demonstrate that S. mitis, S. pneumoniae, and S. oralis produce a (Gro-P)-linked glycolipid via a PG-dependent, ltaS-independent mechanism.ImportanceLTA is an important cell wall component synthesized by Gram-positive bacteria. Disruption of LTA production can confer severe physiological defects and attenuation of virulence. We report here the detection of a biosynthetic precursor of Type I LTA, in addition to the previously characterized Type IV LTA, in the total lipid extracts of S. pneumoniae, S. oralis, and S. mitis. Our results indicate that a novel mechanism is responsible for producing the Type I LTA intermediate. Our results are significant because they identify a novel feature of S. pneumoniae, S. oralis, and S. mitis glycolipid biology.

Identification of subtypes of Chinese schizophrenia patients before discharge: A cluster analysis

2016 ◽  
Vol 33 (S1) ◽  
pp. s257-s257
Author(s):  
S. Liu ◽  
Z. Li
Keyword(s):  
Cluster Analysis ◽  
Cognitive Function ◽  
Self Efficacy ◽  
Self Management ◽  
Type I ◽  
Type Iv ◽  
Neuropsychological Status ◽  
Management Ability ◽  
Competing Interest ◽  
High Level

IntroductionPeople with schizophrenia is a highly heterogeneous group. Identifying subtypes of people with schizophrenia before discharge may help develop targeted discharge plans.ObjectivesTo explore possible subtypes among people with schizophrenia before discharge by their self-management ability, self-efficacy and cognitive function status.AimsTo identify possible subtypes among people with schizophrenia before discharge.MethodsTotally, 150 Chinese people with schizophrenia before discharged from a tertiary psychiatric hospital in Beijing were assessed by Self-management Instrument for People with Schizophrenia and Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Cluster analysis using SPSS 20.0 package was performed to categorize subjects based on their scores.ResultsFour different types of subjects were revealed. Type I low cognition with no participation (n = 25), patients’ self-management ability, self-efficacy and cognitive function were very poor; type II medium cognition with blind confidence (n = 42), patients’ self-efficacy was good, while self-management ability was poor and cognitive function is medium; type III high cognition with high level skill (n = 46), patients’ cognitive function, self-management ability and self-efficacy were good; type IV low cognition with medium level skill (n = 37), patients’ cognition was very poor, while self-management ability and self-efficacy were medium. These four types of subjects had significant differences in long-term use of antipsychotics and primary caregivers’ education level (P < 0.05).ConclusionsThe finding of different subtypes of people with schizophrenia presenting in this sample may help health professionals give effective screening and targeted discharge measures which can further promote patients’ recovery and reduce readmission rates.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Labelling of non-A, non-B hepatitis infected chimpanzee hepatocytes with nuclease-gold conjugates

1984 ◽  
Vol 42 ◽  
pp. 250-251
Author(s):  
G. D. Gagne ◽  
M. F. Miller ◽  
D. A. Peterson
Keyword(s):  
Endoplasmic Reticulum ◽  
Experimental Infection ◽  
Uranyl Acetate ◽  
Type I ◽  
Cellular Injury ◽  
Type Ii ◽  
Tubular Structures ◽  
Type Iii ◽  
Type Iv ◽  
Infected Chimpanzee

Experimental infection of chimpanzees with non-A, non-B hepatitis (NANB) or with delta agent hepatitis results in the appearance of characteristic cytoplasmic alterations in the hepatocytes. These alterations include spongelike inclusions (Type I), attached convoluted membranes (Type II), tubular structures (Type III), and microtubular aggregates (Type IV) (Fig. 1). Type I, II and III structures are, by association, believed to be derived from endoplasmic reticulum and may be morphogenetically related. Type IV structures are generally observed free in the cytoplasm but sometimes in the vicinity of type III structures. It is not known whether these structures are somehow involved in the replication and/or assembly of the putative NANB virus or whether they are simply nonspecific responses to cellular injury. When treated with uranyl acetate, type I, II and III structures stain intensely as if they might contain nucleic acids. If these structures do correspond to intermediates in the replication of a virus, one might expect them to contain DNA or RNA and the present study was undertaken to explore this possibility.

scholarly journals Virulence Factors Found in Nasal Colonization and Infection of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates and Their Ability to Form a Biofilm

Toxins ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 14
Author(s):  
Thamiris Santana Machado ◽  
Felipe Ramos Pinheiro ◽  
Lialyz Soares Pereira Andre ◽  
Renata Freire Alves Pereira ◽  
Reginaldo Fernandes Correa ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Sccmec Type ◽  
Protein A ◽  
Invasive Infection ◽  
Type I ◽  
Methicillin Resistant ◽  
Type Iv ◽  
Spa Gene ◽  
The City

Hospitalizations related to Methicillin-resistant Staphylococcus aureus (MRSA) are frequent, increasing mortality and health costs. In this way, this study aimed to compare the genotypic and phenotypic characteristics of MRSA isolates that colonize and infect patients seen at two hospitals in the city of Niterói—Rio de Janeiro, Brazil. A total of 147 samples collected between March 2013 and December 2015 were phenotyped and genotyped to identify the protein A (SPA) gene, the mec staphylococcal chromosomal cassette (SCCmec), mecA, Panton-Valentine Leucocidin (PVL), icaC, icaR, ACME, and hla virulence genes. The strength of biofilm formation has also been exploited. The prevalence of SCCmec type IV (77.1%) was observed in the colonization group; however, in the invasive infection group, SCCmec type II was prevalent (62.9%). The Multilocus Sequence Typing (MLST), ST5/ST30, and ST5/ST239 analyses were the most frequent clones in colonization, and invasive infection isolates, respectively. Among the isolates selected to assess the ability to form a biofilm, 51.06% were classified as strong biofilm builders. Surprisingly, we observed that isolates other than the Brazilian Epidemic Clone (BEC) have appeared in Brazilian hospitals. The virulence profile has changed among these isolates since the ACME type I and II genes were also identified in this collection.

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