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Virulence factors of Streptococcus anginosus – a molecular perspective
Get PDFStreptococcus anginosus together with S. constellatus and S. intermedius constitute the Streptococcus anginosus group (SAG), until recently considered to be benign commensals of the human mucosa isolated predominantly from oral cavity, but also from upper respiratory, intestinal, and urogenital tracts. For years the virulence potential of SAG was underestimated, mainly due to complications in correct species identification and their assignment to the physiological microbiota. Still, SAG representatives have been associated with purulent infections at oral and non-oral sites resulting in abscesses formation and empyema. Also, life threatening blood infections caused by SAG have been reported. However, the understanding of SAG as potential pathogen is only fragmentary, albeit certain aspects of SAG infection seem sufficiently well described to deserve a systematic overview. In this review we summarize the current state of knowledge of the S. anginosus pathogenicity factors and their mechanisms of action
Developing lactic acid bacteria starter cultures for wholemeal rye flour bread with improved functionality, nutritional value, taste, appearance and safety
Get PDFStarter cultures composed of lactic acid bacteria (LAB) were developed based on the genotypic and phenotypic characterisation of isolates belonging to dominant groups of bacteria in spontaneous rye wholemeal sourdoughs. Combinations of strains have been evaluated on an industrial scale in the sourdough fermentation process. Wholemeal rye bread was prepared using sourdoughs obtained with 3 new starter cultures, and compared to bread made using the commercial culture (LV2). All newly developed cultures used for the preparation of wholemeal rye bread allowed to obtain better quality products as compared to the LV2 based bread. The best results were obtained when the culture containing Lactiplantibacillus plantarum 2MI8 and exopolysaccharide (EPS)-producing Weissella confusa/cibaria 6PI3 strains was applied. The addition of yeast during sourdough breads production, especially the one prepared from mentioned above starter culture, significantly improved their organoleptic properties, their volume and crumb moisture was increased, and also the crumb acidity and hardness was reduced. Fermentation of rye wholemeal dough, especially without the yeast addition, resulted in a significant reduction in the content of higher inositol phosphates as compared to the applied flour, which is associated with improved bioavailability of minerals. The results of this study prove that the investigated new starter cultures can be successfully applied in wholemeal rye bread production
The Impact of Glacial Suspension Color on the Relationship Between Its Properties and Marine Water Spectral Reflectance
Get PDFThis study enabled us to determine the sources of sediment for glacial catchments and investigate the differences in properties, i.e., suspended sediment concentration (SSC), turbidity measured in the laboratory (TLAB) and in the field (TF), mean particle diameter (MPD), and chemical composition, between two different-colored sediments that flowed from the glacier terminus. Additionally, the relationship between these properties for two types of suspensions and remote sensing reflectance (RRS) was tested, and the factor with the greatest impact on the value of RRS
was determined. The results showed that within one catchment
area, there were four sediment sources that provide white (S.1) and red (S.2) sediment. Chemical analysis showed that the differences in sediment color may be influenced by the increased content of carbonates in the white sediment (S.1). The S.2 sediment is characterized by mean TLAB, TF, and SSC values higher than 26.6 formazine nephelometric units (FNU), 13.5 FNU, and 50 mg/L, respectively, and the mean MPD was 4.25 lower than that of the S.1 sediment. However, the red sediment had on average 0.1 lower RRS than the white sediment. In addition, the properties of S.1 correlated better with reflectance, reaching a maximum correlation of 0.69 (SSC/RRS 770–810 nm), while S.2 exhibited a negative correlation in 7 out of 12 cases, reaching a maximum correlation of 0.16 (TLAB/SSC/RRS 730–740 nm) and a negative correlation of −0.37 (SSC/RRS 530–570 nm). This result indicated that sediment color may be a key factor in the dependence of glacial suspension properties and spectral reflectance
Proteomic analysis of carp seminal plasma provides insights into the immune response to bacterial infection of the male reproductive system
Get PDFAeromonas salmonicida is recognized as a significant bacterial pathogen in ulcerative disease of cyprinid fish. However, the mechanism of immunity to these bacteria in common carp is still not well understood, especially the immune regulation in the gonad to bacterial infection. The aims of our study were to analyze changes in the seminal plasma proteome following A. salmonicida infection in carp males. The observed pathological changes in the tissue (liver, spleen, kidney and testis) morphology and upregulation of immune-related genes (tnfa2, il6a) confirmed the successful infection challenge. Using mass spectrometry-based label-free quantitative proteomics, we identified 1402 seminal plasma proteins, and 44 proteins (20 up- and 24 downregulated) were found to be differentially abundant between infected and control males. Most differentially abundant proteins were involved in the immune response mechanisms, such as acute phase response, complement activation and coagulation, inflammation, lipid metabolism, cell-cell and cell-matrix adhesion, creatine-phosphate biosynthesis and germ cell-Sertoli cell junction signaling. Bacterial infection also caused profound changes in expression of selected genes in the testis and hematopoietic organs, which contributed to changes in seminal proteins. The altered seminal proteins and bacterial proteins in seminal plasma may serve as valuable markers of infection in the testis
The Genome of Rhyzopertha dominica (Fab.) (Coleoptera: Bostrichidae): Adaptation for Success
Get PDFThe lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), is a major global pest of cereal grains. Infestations are difficult to control as larvae feed inside grain kernels, and many populations are resistant to both contact insecticides and fumigants. We sequenced the genome of R. dominica to identify genes responsible for important biological functions and develop more targeted and efficacious management strategies. The genome was assembled from long read sequencing and long-range scaffolding technologies. The genome assembly is 479.1 Mb, close to the predicted genome size of 480.4 Mb by flow cytometry. This assembly is among the most contiguous beetle assemblies published to date, with 139 scaffolds, an N50 of 53.6 Mb, and L50 of 4, indicating chromosome-scale scaffolds. Predicted genes from biologically relevant groups were manually annotated using transcriptome data from adults and different larval tissues to guide annotation. The expansion of carbohydrase and serine peptidase genes suggest that they combine to enable efficient digestion of cereal proteins. A reduction in the copy number of several detoxification gene families relative to other coleopterans may reflect the low selective pressure on these genes in an insect that spends most of its life feeding internally. Chemoreceptor genes contain elevated numbers of pseudogenes for odorant receptors that also may be related to the recent ontogenetic shift of R. dominica to a diet consisting primarily of stored grains. Analysis of repetitive sequences will further define the evolution of bostrichid beetles compared to other species. The data overall contribute significantly to coleopteran genetic research
An overlooked hepcidin-cadmium connection
Get PDFHepcidin (DTHFPICIFCCGCCHRSKCGMCCKT), an iron-regulatory hormone, is a 25-amino-acid peptide with four intramolecular disulfide bonds circulating in blood. Its hormonal activity is indirect and consists of marking ferroportin-1 (an iron exporter) for degradation. Hepcidin
biosynthesis involves the N-terminally extended precursors prepro-hepcidin and pro-hepcidin,
processed by peptidases to the final 25-peptide form. A sequence-specific formation of disulfide bonds and export of the oxidized peptide to the bloodstream follows. In this study we considered the fact that prior to export, reduced hepcidin may function as an octathiol ligand bearing some resemblance to the N-terminal part of the �-domain of metallothioneins. Consequently, we studied its ability to bind Zn(II) and Cd(II) ions using the original peptide and a model for prohepcidin extended N-terminally with a stretch of five arginine residues (5R-hepcidin). We found that both form equivalent mononuclear complexes with two Zn(II) or Cd(II) ions saturating all eight Cys residues. The average affinity at pH 7.4, determined from pH-metric spectroscopic titrations, is 10^10.1 M^-1 for Zn(II) ions; Cd(II) ions bind with affinities of 10^15.2 M^-1 and 10^14.1 M^-1. Using mass spectrometry and 5R-hepcidin we demonstrated that hepcidin can compete for Cd(II) ions with metallothionein-2, a cellular cadmium target. This study enabled us to conclude that hepcidin binds Zn(II) and Cd(II) sufficiently strongly to participate in zinc physiology and cadmium toxicity under intracellular conditions
Prefoldin Function in Cellular Protein Homeostasis and Human Diseases
Get PDFCellular functions are largely performed by proteins. Defects in the production, folding, or removal of proteins from the cell lead to perturbations in cellular functions that can result in pathological conditions for the organism. In cells, molecular chaperones are part of a network of surveillance mechanisms that maintains a functional proteome. Chaperones are involved in the folding of newly synthesized polypeptides and assist in refolding misfolded proteins and guiding proteins for degradation. The present review focuses on the molecular co-chaperone prefoldin. Its canonical function in eukaryotes involves the transfer of newly synthesized polypeptides of cytoskeletal proteins to the tailless complex polypeptide 1 ring complex (TRiC/CCT) chaperonin which assists folding of the polypeptide chain in an energy-dependent manner. The canonical function of prefoldin is well established, but recent research suggests its broader function in the maintenance of protein homeostasis under physiological and pathological conditions. Interestingly, non-canonical functions were identified for the prefoldin complex and also for its individual subunits. We discuss the latest findings on the prefoldin complex and its subunits in the regulation of transcription and proteasome-dependent protein degradation and its role in neurological diseases, cancer, viral infections and rare anomalies
Increased contribution of DNA polymerase delta to the leading strand replication in yeast with an impaired CMG helicase complex
Get PDFDNA replication is performed by replisome proteins, which are highly conserved from yeast to humans. The CMG
[Cdc45-Mcm2–7-GINS(Psf1–3, Sld5)] helicase unwinds the double helix to separate the leading and lagging DNA
strands, which are replicated by the specialized DNA polymerases epsilon (Pol ε) and delta (Pol δ), respectively.
This division of labor was confirmed by both genetic analyses and in vitro studies. Exceptions from this rule were described mainly in cells with impaired catalytic polymerase ε subunit. The central role in the recruitment and establishment of Pol ε on the leading strand is played by the CMG complex assembled on DNA during replication
initiation. In this work we analyzed the consequences of impaired functioning of the CMG complex for the di�vision labor between DNA polymerases on the two replicating strands. We showed in vitro that the GINSPsf1–1
complex poorly bound the Psf3 subunit. In vivo, we observed increased rates of L612M Pol δ-specific mutations
during replication of the leading DNA strand in psf1–1 cells. These findings indicated that defective functioning
of GINS impaired leading strand replication by Pol ε and necessitated involvement of Pol δ in the synthesis on this
strand with a possible impact on the distribution of mutations and genomic stability. These are the first results to imply that the division of labor between the two main replicases can be severely influenced by a defective
nonpolymerase subunit of the replisome
Next-generation sequencing of a combinatorial peptide phage library screened against ubiquitin identifies peptide aptamers that can inhibit the in vitro ubiquitin transfer cascade
Get PDFDefining dynamic protein–protein interactions in the ubiquitin conjugation reaction is a challenging research area. Generating peptide aptamers that target components such as ubiquitin itself, E1, E2, or E3 could provide tools to dissect novel features of the enzymatic cascade. Next-generation deep sequencing platforms were used to identify peptide sequences isolated from phage-peptide libraries screened against Ubiquitin and its ortholog NEDD8. In over three rounds of selection under differing wash criteria, over 13,000 peptides were acquired targeting ubiquitin, while over 10,000 peptides were selected against NEDD8. The overlap in peptides against these two proteins was less than 5% suggesting a high degree in specificity of Ubiquitin or NEDD8 toward linear peptide motifs. Two of these ubiquitin-binding peptides were identified that inhibit both E3 ubiquitin ligases MDM2 and CHIP. NMR analysis highlighted distinct modes of binding of the two different peptide aptamers. These data highlight the utility of using next-generation sequencing of combinatorial phage-peptide libraries to isolate peptide aptamers toward a protein target that can be used as a chemical tool in a complex multi-enzyme reaction
Phage Therapy vs. the Use of Antibiotics in the Treatment of Salmonella-Infected Chickens: Comparison of Effects on Hematological Parameters and Selected Biochemical Markers
Get PDFPrevious studies indicated that the use of a phage cocktail, composed of bacteriophages
vB_SenM-2 and vB_Sen-TO17, is effective in killing cells of Salmonella enterica serovars Typhimurium
and Enteritidis in vitro and in the Galleria mellonella animal model as efficiently as antibiotics (enrofloxacin
or colistin) and induced fewer deleterious changes in immune responses. Here, we investigated
the effects of this phage cocktail on the hematological parameters and selected biochemical
markers in chickens infected with S. enterica serovar Typhimurium, in comparison to those caused by
enrofloxacin or colistin. We found that treatment with antibiotics (especially with enrofloxacin) caused
nonbeneficial effects on red blood cell parameters, including hematocrit, MCV, MCH, and MCHC.
However, Salmonella-induced changes in the aforementioned parameters were normalized by the use
of the phage cocktail. Importantly, hepatotoxicity was suggested to be induced by both antibiotics
on the basis of increased alanine transaminase (ALT) and aspartate aminotransferase (AST) activities,
in contrast to the phage cocktail, which did not influence these enzymes. We conclude that phage
therapy with the cocktail of vB_SenM-2 and vB_Sen-TO17 in Salmonella-infected chickens is not only
as effective as antibiotics but also significantly safer for the birds than enrofloxacin and colistin