scholarly journals Genetic and Phenotypic Diversity of Morganella morganii Isolated From Cheese

2021 ◽  
Vol 12 ◽  
Author(s):  
Lorenz Timo Ryser ◽  
Emmanuelle Arias-Roth ◽  
Vincent Perreten ◽  
Stefan Irmler ◽  
Rémy Bruggmann
Keyword(s):  
Phenotypic Diversity ◽  
Distinct Species ◽  
Morganella Morganii ◽  
Gene Encoding ◽  
Antimicrobial Resistance Genes ◽  
Genes Encoding ◽  
Lysine Trna ◽  
Unknown Gene ◽  
Do So

The bacterium Morganella morganii can produce the biogenic amines (BA) cadaverine, putrescine, and histamine in vitro and is responsible for high histamine concentrations in fish products. These BA can have toxic effects upon ingestion and are undesired in food. The purpose of this study was to characterize the phenotype and genotype of 11 M. morganii isolated from cheese in regard to the BA formation. In addition, we investigated the phylogeny, trehalose fermentation ability, and antibiotic resistance of the cheese isolates. To do so, we sequenced their genomes using both long and short read technologies. Due to the presence of the trehalose operon and the ability to ferment trehalose, the cheese isolates can be assigned to the subsp. sibonii. Comparative genomics with public available M. morganii genomes shows that the genomes of the cheese isolates cluster together with other subsp. sibonii genomes. All genomes between subsp. morganii and subsp. sibonii are separated by an average nucleotide identity (ANI) of less than 95.0%. Therefore, the subspecies could represent two distinct species. Nine of the strains decarboxylated lysine yielding cadaverine in vitro. This metabolic activity is linked to a previously unknown gene cluster comprising genes encoding a lysine-tRNA ligase (lysS), an HTH-transcriptional regulator (argP), a cadaverine-lysine antiporter (cadB), and a lysine decarboxylase (cadA). The formation of putrescine is linked to the speF gene encoding an ornithine decarboxylase. The gene is disrupted in five strains by an insertion sequence, and these strains only exhibit a weak putrescine production. Antimicrobial susceptibility profiling revealed that all cheese strains are resistant to tetracycline, chloramphenicol, tigecycline, colistin, and ampicillin. These phenotypes, except for colistin which is intrinsic, could be linked to antimicrobial resistance genes located on the chromosome.

scholarly journals Phosphorylation of Nucleosides by the Mutated Acid Phosphatase from Morganella morganii

2000 ◽  
Vol 66 (7) ◽  
pp. 2811-2816 ◽  
Author(s):  
Yasuhiro Mihara ◽  
Takashi Utagawa ◽  
Hideaki Yamada ◽  
Yasuhisa Asano
Keyword(s):  
Acid Phosphatase ◽  
Random Mutagenesis ◽  
Reaction Yield ◽  
Mutant Library ◽  
Morganella Morganii ◽  
Gene Encoding ◽  
E Coli ◽  
Acid Phosphatase Gene ◽  
Phosphate Source

ABSTRACT A novel nucleoside phosphorylation process using the food additive pyrophosphate as the phosphate source was investigated. TheMorganella morganii gene encoding a selective nucleoside pyrophosphate phosphotransferase was cloned. It was identical to theM. morganii PhoC acid phosphatase gene. Sequential in vitro random mutagenesis was performed on the gene by error-prone PCR to construct a mutant library. The mutant library was introduced intoEscherichia coli, and the transformants were screened for the production of 5′-IMP. One mutated acid phosphatase with an increased phosphotransferase reaction yield was obtained. With E. coli overproducing the mutated acid phosphatase, 101 g of 5′-IMP per liter (192 mM) was synthesized from inosine in an 88% molar yield. This improvement was achieved with two mutations, Gly to Asp at position 92 and Ile to Thr at position 171. A decreasedKm value for inosine was responsible for the increased productivity.

scholarly journals Casein Kinase 1 Delta Regulates the Pace of the Mammalian Circadian Clock

2009 ◽  
Vol 29 (14) ◽  
pp. 3853-3866 ◽  
Author(s):  
Jean-Pierre Etchegaray ◽  
Kazuhiko K. Machida ◽  
Elizabeth Noton ◽  
Cara M. Constance ◽  
Robert Dallmann ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Perinatal Period ◽  
Casein Kinase ◽  
Gene Encoding ◽  
Exon 2 ◽  
Casein Kinase 1 ◽  
Functional Differences ◽  
Clock Proteins ◽  
Genes Encoding

ABSTRACT Both casein kinase 1 delta (CK1δ) and epsilon (CK1ε) phosphorylate core clock proteins of the mammalian circadian oscillator. To assess the roles of CK1δ and CK1ε in the circadian clock mechanism, we generated mice in which the genes encoding these proteins (Csnk1d and Csnk1e, respectively) could be disrupted using the Cre-loxP system. Cre-mediated excision of the floxed exon 2 from Csnk1d led to in-frame splicing and production of a deletion mutant protein (CK1δΔ2). This product is nonfunctional. Mice homozygous for the allele lacking exon 2 die in the perinatal period, so we generated mice with liver-specific disruption of CK1δ. In livers from these mice, daytime levels of nuclear PER proteins, and PER-CRY-CLOCK complexes were elevated. In vitro, the half-life of PER2 was increased by ∼20%, and the period of PER2::luciferase bioluminescence rhythms was 2 h longer than in controls. Fibroblast cultures from CK1δ-deficient embryos also had long-period rhythms. In contrast, disruption of the gene encoding CK1ε did not alter these circadian endpoints. These results reveal important functional differences between CK1δ and CK1ε: CK1δ plays an unexpectedly important role in maintaining the 24-h circadian cycle length.

scholarly journals Screening of Antimicrobial Resistance Genes and Epidemiological Features in Hospital and Community-Associated Carbapenem Resistant Pseudomonas aeruginosa Infections

2020 ◽  
Author(s):  
ayse erturk ◽  
Ayşegül Çopur ÇİÇEK ◽  
Nebahat EJDER ◽  
Uğur KOSTAKOĞLU ◽  
İlknur Esen YILDIZ ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Multidrug Resistant ◽  
Gene Encoding ◽  
Pfge Typing ◽  
Carbapenem Resistant ◽  
Antimicrobial Resistance Genes ◽  
Genes Encoding ◽  
Pcr Method ◽  
Vitek 2 ◽  
Hospital Acquired

Abstract Background: Researching carbapenem-resistant isolates and the use of antibiotics and following infection control policies enable the identification of carbapenemase-producing bacteria and prevent their spread.Methods: P. aeruginosa isolates were recovered from Medicine Faculty of Recep Tayyip Erdoğan University between April 2015 and October 2016 and identified by conventional methods and the automated Vitek 2 Compact (BioMerieux, France) system. Antimicrobial susceptibility experiments were performed in accordance with CLSI criteria and the automated Vitek 2 Compact system. The PCR method was investigated for the presence of β-lactamase resistance genes. PFGE typing was performed to show clonal relation among samples.Results: Seventy P. aeruginosa strains were isolated from seventy patients. The median age of 70 cases was found 66 with minimum 17 and maximum 92 years old. 67.1% of the patients had contact with the health service in the last 90 days and 75.7% of the patients had received antimicrobial therapy in the previous 90 days. The most common comorbidity was cardiovascular diseases. Twenty-four (34.3%) strains were carbapenem resistant, 2 strains were multidrug-resistant except colistin, and none of the samples had colistin resistance. The gene encoding β-lactamase or metallo-β-lactamase was found in a total of 36 strains. The bla VEB gene was identified in only 1 strain alone, but in combination with other resistance genes in a total of 17 strains. While the bla PER gene was detected in 5 samples alone, it was found in 13 samples in combination with other genes. Among the genes encoding metallo-β-lactamase, the most bla NDM positive was detected (n=22), followed by 14 positive samples of bla KPC . bla IMP and bla VIM were detected in 5 and 1 samples, respectively. Also, the association of bla VEB - bla PER and bla VEB - bla KPC - bla NDM was found to be very high. Much more resistance genes and associations were detected in hospital-acquired samples than community-acquired samples, both proportionally and in terms of co-occurrence. Most of the community-associated strains were collected in the F2 clade, while most of the hospital-associated strains were collected in the G1 clade. However, no difference was found between the community and hospital-associated strains according to PFGE results. Simultaneously, other microorganisms were also isolated from patients from which these 6 P. aeruginosa strains were isolated. Of these patients, 5 patients died, except the number 70.Conclusions: The median length of stay (days) was found to be significantly higher in the group with HAI than in the group with CAI. Compared to sample 28 and 37, which carried 5 β-lactamase coding genes, the death of these 5 patients with fewer or no resistance genes showed that the coexistence of other factors - especially other microorganisms in addition to resistance genes, was important.

Transposon-Derived Brucella abortusRough Mutants Are Attenuated and Exhibit Reduced Intracellular Survival

1998 ◽  
Vol 66 (3) ◽  
pp. 1008-1016 ◽  
Author(s):  
Chris A. Allen ◽  
L. Garry Adams ◽  
Thomas A. Ficht
Keyword(s):  
Sequence Analysis ◽  
Polymyxin B ◽  
Intracellular Survival ◽  
Phagocytic Cells ◽  
Gene Encoding ◽  
Amphipathic Peptide ◽  
O Antigen ◽  
Genes Encoding ◽  
Definition Of

ABSTRACT The O antigen of Brucella abortus has been described as a major virulence determinant based on the attenuated survival of fortuitously isolated rough variants. However, the lack of genetic definition of these mutants and the virulence of naturally occurring rough species, Brucella ovis and Brucella canis, has confused interpretation. To better characterize the role of O antigen in virulence and survival, transposon mutagenesis was used to generate B. abortus rough mutants defective in O-antigen presentation. Sequence analysis of DNA flanking the site of Tn5 insertion was used to verify insertion in genes encoding lipopolysaccharide (LPS) biosynthetic functions. Not surprisingly, each of the rough mutants was attenuated for survival in mice, but unexpected differences among the mutants were observed. In an effort to define the basis for the observed differences, the structure of the rough LPS and the sensitivity of these mutants to individual killing mechanisms were examined in vitro. All of the B. abortus rough mutants exhibited a 4- to 5-log-unit increase, compared to the smooth parental strain, in sensitivity to complement-mediated lysis. Little change was evident in the sensitivity of these organisms to hydrogen peroxide, consistent with an inability of O antigen to exclude relatively small molecules. Sensitivity to polymyxin B, which was employed as a model cationic, amphipathic peptide similar to defensins found in phagocytic cells, revealed survival differences among the rough mutants similar to those observed in the mouse. One mutant in particular exhibited hypersensitivity to polymyxin B and reduced survival in mice. This mutant was characterized by a truncated rough LPS. DNA sequence analysis of this mutant revealed a transposon interruption in the gene encoding phosphomannomutase (pmm), suggesting that this activity may be required for the synthesis of a full-length core polysaccharide in addition to O antigen. B. abortus O antigen appears to be essential for extra- and intracellular survival in mice.

scholarly journals In vitro activity of ceftazidime/avibactam against isolates of carbapenem-non-susceptible Enterobacteriaceae collected during the INFORM global surveillance programme (2015–17)

2019 ◽  
Vol 75 (2) ◽  
pp. 384-391 ◽  
Author(s):  
Iris Spiliopoulou ◽  
Krystyna Kazmierczak ◽  
Gregory G Stone
Keyword(s):  
Antimicrobial Activity ◽  
In Vitro Activity ◽  
Broth Microdilution ◽  
Gene Encoding ◽  
Surveillance Programme ◽  
Genes Encoding ◽  
The Usa ◽  
Report Data ◽  
Pcr Assays

Abstract Objectives To report data for ceftazidime/avibactam and comparators against meropenem-non-susceptible Enterobacteriaceae collected globally (excluding centres in the USA) from 2015 to 2017 as part of the International Network For Optimal Resistance Monitoring (INFORM) surveillance programme. Methods MICs and susceptibility were determined using EUCAST broth microdilution methodology and EUCAST breakpoints. Isolates were screened to detect genes encoding β-lactamases using multiplex PCR assays. MBL-positive isolates were those in which one or more of the IMP, VIM and/or NDM genes were detected. Results A total of 1460 meropenem-non-susceptible isolates were collected and, of the agents on the panel, susceptibility was highest to ceftazidime/avibactam, colistin and tigecycline [73.0%, 77.0% (1081/1403) and 78.1%, respectively]. Ceftazidime/avibactam was not active against MBL-positive isolates (n=367); these isolates showed the highest rates of susceptibility to colistin (92.1%, 303/329), tigecycline (71.9%) and amikacin (46.6%). A total of 394 isolates were resistant to ceftazidime/avibactam and, of the 369 isolates that were screened, 98.4% were found to carry a gene encoding an MBL enzyme. Among isolates that were identified as carbapenemase positive and MBL negative (n=910), susceptibility was highest to ceftazidime/avibactam (99.8%). Susceptibility was also highest to ceftazidime/avibactam among isolates that were carbapenemase negative and MBL negative (94/98, 95.9%). Conclusions These data highlight the need for continued surveillance of antimicrobial activity as well as the need for new antimicrobials to treat infections caused by meropenem-non-susceptible Enterobacteriaceae, for which the options are extremely limited.

scholarly journals Identification of an Operon Required for Ferrichrome Iron Utilization in Vibrio cholerae

2000 ◽  
Vol 182 (8) ◽  
pp. 2350-2353 ◽  
Author(s):  
Marc B. Rogers ◽  
Jessica A. Sexton ◽  
G. Joel DeCastro ◽  
Stephen B. Calderwood
Keyword(s):  
Escherichia Coli ◽  
Vibrio Cholerae ◽  
Predicted Amino Acid Sequence ◽  
Gene Fusions ◽  
Gene Encoding ◽  
E Coli ◽  
Atp Binding Cassette Transporter ◽  
Genes Encoding ◽  
Iron Utilization

ABSTRACT Mutagenesis of Vibrio cholerae with TnphoA, followed by screening for fusions that were activated under low-iron conditions, led to the identification of seven independent fusion strains, each of which was deficient in the ability to utilize ferrichrome as a sole iron source for growth in a plate bioassay and had an insertion in genes encoding products homologous toEscherichia coli FhuA or FhuD. Expression of the gene fusions was independent of IrgB but regulated by Fur. We report here a map of the operon and the predicted amino acid sequence of FhuA, based on the nucleotide sequence. Unlike those of the E. coli fhuoperon, the V. cholerae ferrichrome utilization genes are located adjacent and opposite in orientation to a gene encoding an ATP-binding cassette transporter homolog, but this gene, if disrupted, does not affect the utilization of ferrichrome in vitro.

scholarly journals Generation of Synthetic Severe Acute Respiratory Syndrome Coronavirus Pseudoparticles: Implications for Assembly and Vaccine Production

2004 ◽  
Vol 78 (22) ◽  
pp. 12557-12565 ◽  
Author(s):  
Yue Huang ◽  
Zhi-yong Yang ◽  
Wing-pui Kong ◽  
Gary J. Nabel
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Buoyant Density ◽  
Open Reading Frames ◽  
Expression Vectors ◽  
Gene Encoding ◽  
Transmission Electron ◽  
Genes Encoding ◽  
Necessary And Sufficient ◽  
N Proteins

ABSTRACT The recently emerged severe acute respiratory syndrome coronavirus (SARS-CoV) contains four structural genes, two replicase-transcriptase open reading frames, and more than five potential genes of unknown function. Despite this relative simplicity, the molecular regulation of SARS-CoV replication and assembly is not understood. Here, we report that two viral genes, encoding the SARS-CoV membrane (M) and nucleocapsid (N) proteins, are necessary and sufficient for formation of virus-like particles. Expression vectors encoding these two proteins were synthesized by using preferred human codons. When M and N expression plasmids were cotransfected into human 293 renal epithelial cells, pseudoparticles formed readily. The addition of a third gene, encoding the spike (S) glycoprotein, facilitated budding of particles that contained a corona-like halo resembling SARS-CoV when examined by transmission electron microscopy, with a buoyant density characteristic of coronaviruses. Specific biochemical interactions of these proteins were also shown in vitro. The S, M, and N proteins of the SARS-CoV are, therefore, necessary and sufficient for pseudovirus assembly. These findings advance the understanding of the morphogenesis of SARS-CoV and enable the generation of safe, conformational mimetics of the SARS virus that may facilitate the development of vaccines and antiviral drugs.

Plant pre-m RNA splicing and splicing components

1993 ◽  
Vol 342 (1301) ◽  
pp. 217-224 ◽  
Keyword(s):  
Transgenic Plants ◽  
Rna Splicing ◽  
Specific Protein ◽  
Messenger Rnas ◽  
Rna Helicases ◽  
Gene Encoding ◽  
Small Nuclear Ribonucleoprotein ◽  
Genes Encoding ◽  
Snrnp Protein

Pre-mRNA splicing or the removal of introns from precursor messenger RNAs depends on the accurate recognition of intron sequences by the plant splicing machinery. The major components of this machinery are small nuclear ribonucleoprotein protein particles (snRNPs) which consist of snRNAs and snRNP proteins. We have analysed various aspects of intron sequence and structure in relation to splice site selection and splicing efficiency and we have cloned snRNA genes and a gene encoding the snRNP protein, U2B". In the absence of an in vitro splicing system for plants, transient expression in protoplasts and stable plant transform ations have been used to analyse splicing of intron constructs. We aim to address the function of the UsnRNP-specific protein, U2B", via the production of transgenic plants expressing antisense U2B" transcripts and epitope-tagged U2B" protein. In addition, we have cloned genes encoding other proteins which potentially interact with RNA, such as RNA helicases, and strategies involving transgenic plants are being developed to analyse their function.

Fate and function of the ventral ectodermal ridge during mouse tail development

Development ◽  
2000 ◽  
Vol 127 (10) ◽  
pp. 2113-2123
Author(s):  
D.C. Goldman ◽  
G.R. Martin ◽  
P.P. Tam
Keyword(s):  
Ventral Surface ◽  
The Body ◽  
Gene Encoding ◽  
Surface Ectoderm ◽  
Tail Development ◽  
Genes Encoding ◽  
And Function ◽  
And Control ◽  
Bmp Antagonist

In the mouse embryo, the body axis continues to develop after gastrulation as a tail forms at the posterior end of the embryo. Little is known about what controls outgrowth and patterning of the tail, but it has been speculated that the ventral ectodermal ridge (VER), a morphologically distinct ectoderm on the ventral surface near the tip of the tail, is a source of signals that regulate tail development (Gruneberg, H. (1956). Nature 177, 787–788). We tested this hypothesis by ablating all or part of the VER and assessing the effects of such ablations on the development of tail explants cultured in vitro. The data showed that the VER produces signals necessary for somitogenesis in the tail and that the cells that produce these signals are localized in the middle and posterior region of the VER. Dye labeling experiments revealed that cells from these regions move anteriorly within the VER and eventually exit it, thereby colonizing the ventral surface ectoderm anterior to the VER. In situ hybridization analysis showed that the genes encoding the signaling molecules FGF17 and BMP2 are specifically expressed in the VER. Assays for gene expression in VER-ablated and control tails were performed to identify targets of VER signaling. The data showed that the VER is required for expression of the gene encoding the BMP antagonist noggin in the tail ventral mesoderm, leading us to speculate that one of the major functions of the VER in tail development is to regulate BMP activity.

scholarly journals Expression of genes encoding resistance in Staphylococcus spp. isolated from bovine subclinical mastitis in Brazil

2020 ◽  
Vol 14 (07) ◽  
pp. 772-780
Author(s):  
Eveline Zuniga ◽  
Nilson Roberti Benites ◽  
Aline Santana da Hora ◽  
Priscila Luiza Mello ◽  
Marco Antonio Laes ◽  
...  
Keyword(s):  
Methicillin Resistance ◽  
Meca Gene ◽  
Bovine Mastitis ◽  
Subclinical Mastitis ◽  
Gene Encoding ◽  
Resistance Factors ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Staphylococcus Spp

Introduction: Staphylococci are the most important agents associated with bovine mastitis. This study aimed at characterizing resistance factors to antimicrobials in Staphylococcus spp. isolated from the milk of cows with subclinical mastitis. Methodology: In vitro resistance of 243 Staphylococcus spp. isolates to antimicrobials commonly used in clinical practice was evaluated. The detection and expression of genes encoding resistance mecA (gene encoding penicillin binding protein 2a) mecALGA251 (mecA homologue), blaZ (gene encoding penicillin resistance), femA and femB (genes encoding essential factors - A and B - for the expression of methicillin resistance) and aacA-aphD (gene encoding for a bifunctional enzyme that confers resistance to gentamicin) using PCR and RT-PCR was investigated. Results: One or more genes encoding resistance to different antimicrobials were detected in 184 Staphylococcus spp. samples. The femA and femB genes were the most frequent. Regarding the variables’ detection (N = number of strains) and expression (% of strains), the following results were obtained: blaZ (N = 40 – 82.5%), femA (N = 147 – 47.6%), aacAaphD (N = 30 – 43.3%), femB (N = 138 – 29.7%), mecA (N = 33 – 27.3%), mecALGA251 (N = 01 – 0.0%). There was a higher occurrence of phenotypic resistant strains for amoxicillin, ampicillin and penicillin in isolates positive for detection and/or expression of blaZ gene when compared with the other genes. Conclusions: The present study provides new information on genotypic traits of Staphylococcus isolates from bovine subclinical mastitis especially regarding the evaluation of expression of genes associated with antimicrobial resistance in Staphylococcus spp. using molecular tools.

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