scholarly journals The molecular mechanism ofN-acetylglucosamine side-chain attachment to the Lancefield group A carbohydrate inStreptococcus pyogenes

2017 ◽  
Vol 292 (47) ◽  
pp. 19441-19457 ◽  
Author(s):  
Jeffrey S. Rush ◽  
Rebecca J. Edgar ◽  
Pan Deng ◽  
Jing Chen ◽  
Haining Zhu ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Side Chain ◽  
Group A ◽  
Lancefield Group

scholarly journals The molecular mechanism of N-acetylglucosamine side-chain attachment to the Lancefield group A Carbohydrate inStreptococcus pyogenes

2017 ◽  
Author(s):  
Jeffrey S. Rush ◽  
Rebecca J. Edgar ◽  
Pan Deng ◽  
Jing Chen ◽  
Haining Zhu ◽  
...  
Keyword(s):  
Cell Envelope ◽  
Mass Spectrometry Analysis ◽  
Side Chain ◽  
Antigenic Determinants ◽  
Limited Attention ◽  
Spectrometry Analysis ◽  
Gram Positive Bacteria ◽  
Essential Components ◽  
Group A ◽  
Lancefield Group

AbstractIn many Lactobacillales species (i.e. lactic acid bacteria), peptidoglycan is decorated by polyrhamnose polysaccharides that are critical for cell envelope integrity and cell shape and also represent key antigenic determinants. Despite the biological importance of these polysaccharides, their biosynthetic pathways have received limited attention. The important human pathogen,Streptococcus pyogenes, synthesizes a key antigenic surface polymer—the Lancefield group A carbohydrate (GAC). GAC is covalently attached to peptidoglycan and consists of a polyrhamnose polymer, with N-acetylglucosamine (GlcNAc) side chains, which is an essential virulence determinant. The molecular details of the mechanism of polyrhamnose modification with GlcNAc are currently unknown. In this report, using molecular genetics, analytical chemistry and mass spectrometry analysis, we demonstrated that GAC biosynthesis requires two distinct undecaprenol-linked GlcNAc-lipid intermediates: GlcNAc-pyrophosphorylundecaprenol (GlcNAc-P-P-Und) produced by the GlcNAc-phosphate transferase GacO and GlcNAc-phosphate-undecaprenol (GlcNAc-P-Und) produced by the glycosyltransferase GacI. Further investigations revealed that the GAC polyrhamnose backbone is assembled on GlcNAc-P-P-Und. Our results also suggested that a GT-C glycosyltranferase, GacL, transfers GlcNAc from GlcNAc-P-Und to polyrhamnose. Moreover, GacJ, a small membrane-associated protein, formed a complex with GacI and significantly stimulated its catalytic activity. Of note, we observed that GacI homologs perform a similar function inStreptococcus agalactiaeandEnterococcus faecalis. In conclusion, the elucidation of GAC biosynthesis inS. pyogenesreported here enhances our understanding of how other Gram-positive bacteria produce essential components of their cell wall.

scholarly journals THE ANTIGENIC STRUCTURE OF HEMOLYTIC STREPTOCOCCI OF LANCEFIELD GROUP A

1942 ◽  
Vol 142 (2) ◽  
pp. 823-833
Author(s):  
Charles A. Zittle ◽  
Tzvee N. Harris
Keyword(s):  
Antigenic Structure ◽  
Group A ◽  
Lancefield Group

scholarly journals Preparation of side chain liquid crystal polyether chelating resin and its adsorption properties for Cu2+ in water

2021 ◽  
Author(s):  
Chaoyi Qian ◽  
Meng Li ◽  
Shuang Wang ◽  
Qing Gao ◽  
Huaiwei Yao ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Influence Factors ◽  
Chelating Resin ◽  
Side Chain ◽  
Order Kinetic ◽  
Adsorption Model ◽  
Order Kinetic Model ◽  
Group A ◽  
New Type ◽  
Cationic Ring Opening Polymerization

Abstract With epoxycyclohexane as critical modifying monomer, the copolyether was obtained by cationic ring-opening polymerization of epichlorohydrin and epoxycyclohexane. Then biphenyl was used as the mesogen, and diglycolamidic acid was used as the terminal chelating group, a new type of side chain liquid crystal polyether chelating resin was prepared at last. The adsorption influence factors, reuse performance, adsorption model and adsorption kinetics of the chelated resin on Cu 2+ in water were studied systematically. The results showed that the resin has good adsorption and reuse performance for the treatment of Cu 2+ in water, and the adsorption of Cu 2+ is Langmuir monolayer adsorption, and the adsorption process conforms to a quasi-second-order kinetic model. The adsorption performances of the chelated resin has great potential for recovery of copper resource from non-ferrous smelting industry.

scholarly journals Effects of N-Substituents on the Functional Activities of Naltrindole Derivatives for the δ Opioid Receptor: Synthesis and Evaluation of Sulfonamide Derivatives

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3792
Author(s):  
Chiharu Iwamatsu ◽  
Daichi Hayakawa ◽  
Tomomi Kono ◽  
Ayaka Honjo ◽  
Saki Ishizaki ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Opioid Receptor ◽  
Inverse Agonist ◽  
Side Chain ◽  
Agonist Activity ◽  
Inverse Agonists ◽  
Functional Activities ◽  
Δ Opioid Receptor

We have recently reported that N-alkyl and N-acyl naltrindole (NTI) derivatives showed activities for the δ opioid receptor (DOR) ranging widely from full inverse agonists to full agonists. We newly designed sulfonamide-type NTI derivatives in order to investigate the effects of the N-substituent on the functional activities because the side chain and S=O part in the sulfonamide moiety located in spatially different positions compared with those in the alkylamine and amide moieties. Among the tested compounds, cyclopropylsulfonamide 9f (SYK-839) was the most potent full inverse agonist for the DOR, whereas phenethylsulfonamide 9e (SYK-901) showed full DOR agonist activity with moderate potency. These NTI derivatives are expected to be useful compounds for investigation of the molecular mechanism inducing these functional activities.

scholarly journals Evaluation of a two-minute strep A direct swab test (SADST) on patients with pharyngitis at a primary care clinic

1986 ◽  
Vol 97 (1) ◽  
pp. 133-138 ◽  
Author(s):  
G. F. Araj ◽  
H. A. Majeed
Keyword(s):  
Primary Care ◽  
Primary Care Clinic ◽  
Culture Method ◽  
Care Clinic ◽  
Predictive Values ◽  
Primary Care Clinics ◽  
Clinical Laboratories ◽  
Standard Culture ◽  
Group A ◽  
Lancefield Group

SUMMARYA two-minute strep A direct swab test (SADST) was used to detect the presence of Lancefield group A streptococci (GAS) from the throats of 207 patients with pharyngitis at a primary-care clinic. The results were compared with a standard culture method. Fifty-one specimens were positive and 156 specimens were negative for GAS by culture. The SADST had a sensitivity of 96% (49 of 51) and specificity of 98·7% (154 of 156). The predictive values of a positive and negative SADST, for GAS, were 96% and 98·7 % respectively. The SADST showed negative reactions with five specimens containing beta-haemotytic streptococci other than GAS and 34 known stock cultures other than GAS. Our results indicate that SADST is a rapid, simple, convenient and reliable test to use for diagnosis of GAS pharyngitis at primary care clinics, physicians' offices and clinical laboratories.

scholarly journals Milk epidemic of angina, originating from a Cow with mastitis and due to Streptococcus pyogenes (Lancefield group A)

1938 ◽  
Vol 38 (3) ◽  
pp. 384-391 ◽  
Author(s):  
E. Juel Henningsen ◽  
J. Ernst
Keyword(s):  
Sore Throat ◽  
Streptococcus Pyogenes ◽  
Raw Milk ◽  
Slight Degree ◽  
Group A ◽  
The Village ◽  
Lancefield Group

A report is given of a milk epidemic of septic sore throat, comprising about 100 cases.The epidemic originated from a cow with a slight degree of mastitis, produced by a Streptococcus pyogenes (Lancefield's group A).The same Streptococcus (which we did not succeed in typing) was isolated from 74% of the patients examined and from three persons who were handling the milk.It seems reasonable to assume that the cow was infected from the milkers. Owing to particular conditions in the distribution of the raw milk, it is possible that the milk delivered raw in the village involved on one day a massive contamination.The epidemic is characterized as moderately severe. No case terminated fatally.

Severe Peritonitis during CAPD Due to Beta-hemolytic Streptococcus, Lancefield Group A

1983 ◽  
Vol 3 (2) ◽  
pp. 109-109 ◽  
Author(s):  
C. Dadone ◽  
L. Bonoldi ◽  
G. Giltri ◽  
L. Vigore ◽  
P. Mariani ◽  
...  
Keyword(s):  
Hemolytic Streptococcus ◽  
Beta Hemolytic Streptococcus ◽  
Severe Peritonitis ◽  
Group A ◽  
Lancefield Group

scholarly journals Molecular mechanism of strigolactone perception by DWARF14

2014 ◽  
Vol 70 (a1) ◽  
pp. C1062-C1062
Author(s):  
Masaru Tanokura ◽  
Takuya Miyakawa ◽  
You-Lin Xue ◽  
Hidemitsu Nakamura ◽  
Feng Hou ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Crop Yields ◽  
Complex Structure ◽  
Hydrophobic Surface ◽  
Side Chain ◽  
Synthetic Analogue ◽  
Shoot Branching ◽  
Dependent Manner ◽  
Small Compound ◽  
A Site

The terpenoid, small-compound strigolactones (SLs) are plant hormones that regulate plant shoot branching, which is an important agronomic trait that determines crop yields. An α/β-hydrolase protein, DWARF14 (D14), has been recognized to be an essential component of plant SL signaling. Recently, it has been demonstrated that D14 interacts with a gibberellin (GA)-signaling repressor SLR1 in an SL-dependent manner [1], which suggests that SLR1 mediates crosstalk between the SL and GA signalings in the regulation of plant shoot branching. Although D14 functions in SL perception to promote the interaction with SLR1, its molecular mechanism remains unclear. Here, we report the crystal structure of D14 in the complex with 5-hydroxy-3-methylbutenolide (D-OH), which is a reaction product of SLs. The structure was solved at a 2.10-Å resolution when an SL synthetic analogue, (–)-ent-2'-epi-GR7, was soaked into D14 crystals [1]. In the complex structure, D-OH was located at a site far from the catalytic residues including H297 and appeared to function as a plug for the catalytic cavity to induce an overall hydrophobic surface with a hydrophilic patch between the two α-helices in the cap structure of D14. In the binding site, the indole amine of Trp205 formed a hydrogen bond with the oxygen atom of the C2' hydroxy group, which arose from the catalytic reaction of D14, instead of a water molecule in the structure of apo D14. In addition, the side chain of Phe245 moved 1.3 Å toward D-OH. Mutational analyses of D14 showed that the interaction between D14 and SLR1 required an enzymatic activity of D14 and the residues Trp205 and Phe245 were essential for the SL-dependent SLR1-binding of D14. These results suggest that the D14–D-OH complex mediates the interaction with SLR1 in which the D-OH-induced surface and/or structural change is crucial.

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