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1

Utilization of 4-n-nonylphenol by Metarhizium sp. isolates

100%

Różalska S., Pawłowska J., Wrzosek M., Tkaczuk C., Długoński J.

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2013

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vol. 60

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issue 4

677-682

EN

Nonylphenol (4-NP) is a xenobiotic classified as an endocrine disrupting compound with an ability to interfere with hormonal systems of numerous organisms including humans. It is widely distributed not only in aquatic but also in terrestrial systems. The aim of this study was to evaluate the ability of cosmopolitan fungus Metarhizium (commonly persistent in soil as a facultative insect pathogen, controlling populations of arthropods in natural environment) to degrade 4-n-nonylphenol. All isolates examined in this work were identified to a species rank based on five, independent genetic markers. Among eight Metarhizium strains; six of them have been identified as M. robertsii, and two others as M. brunneum and M. lepidiotae. All investigated Metarhzium isolates were found to eliminate 4-n-NP with significant efficiency (initial xenobiotic concentration 50 mg L-1). The degradation process was very effective and at 24h of incubation 50-90% of 4-n-NP was eliminated by certain strains, while extended incubation resulted in further utilization of this compound. At the end of the experiments 64-99% of 4-n-NP was removed from the culture medium. Additionally, in all tested cultures three major metabolites were detected: 4-hydroxybenzoic acid; 2-(4-hydroxyphenyl)acetic acid and 4-hydroxyphenylpentanoic acid. The obtained results indicate that Metarhizium sp. possesses an ability to degrade NP and can serve as a potential candidate for further biodegradation studies.

2

Odyssey of Agrobacterium T-DNA.

100%

Ziemienowicz A.

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2001

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vol. 48

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issue 3

623-635

EN

Agrobacterium tumefaciens, a plant pathogen, is characterized by the unique feature of interkingdom DNA transfer. This soil bacterium is able to transfer a fragment of its DNA, called T-DNA (transferred DNA), to the plant cell where T-DNA is integrated into the plant genome leading to "genetic colonization" of the host. The fate of T-DNA, its processing, transfer and integration, resembles the journey of Odysseus, although our hero returns from its long trip in a slightly modified form.The soil bacterium, Agrobacterium tumefaciens, is a plant pathogen responsible for tumor induction on dicotyledonous plants due to its ability to transfer DNA to the plant cell (reviewed in: de la Cruz & Lanka, 1998; Gelvin, 2000; Hansen & Chilton, 1999; Lartey & Citovsky, 1997; Rossi et al., 1998; Zupan & Zambryski, 1997). In biotechnology this ability is widely used for plant transformation. During tumor induction Agrobacterium attaches to plant cells and then transfers part of its DNA to some of these cells. The transferred DNA (T-DNA) which resides on a large Ti (tumor inducing) plasmid, is processed within the bacterium and is exported to the plant where it becomes integrated into the plant genome (reviewed in: Sheng & Citovsky, 1996; Tinland & Hohn, 1995; Tinland, 1996). Proteins encoded by the virulence (vir) region of the Ti plasmid regulate T-DNA processing and transfer. Phenolic compounds derived from a wounded plant cell wall induce expression of the vir region genes. Virulence proteins recognize 25 bp imperfect direct repeats (border sequences) that define the T-DNA. In the presence of VirD1 protein, VirD2 cleaves the border sequence in a site- and strand-specific manner and subsequently becomes covalently attached to the 5' end of the nicked DNA. The nicked DNA is then displaced from the plasmid producing single-stranded T-DNA. The T-DNA-VirD2 complex and the VirE2 protein are believed to be transferred to the plant through a pilus-like structure containing VirB and VirD4 proteins. In the plant cell, T-DNA becomes coated with the single-stranded DNA-binding protein, VirE2. The T-DNA-protein complex is imported into the nucleus where the T-DNA is integrated into the nuclear genome. Expression of genes located on T-DNA leads to the formation of proteins involved in the production of auxins and cytokinins. These plant hormones cause the tumorous phenotype that is characterized by the ability of the plant cells to proliferate limitlessly and autonomously even in the absence of added phytohormones. Crown gall tumors are characterized by the production of opines (amino-acid derivatives). The biosynthesis of opines is catalyzed by opine synthases, which are encoded by the T-DNA. Opines formed in the tumors can be metabolized by the tumorigenic agrobacteria, but not by most of the other soil organisms. Thus, Agrobacterium creates for itself a favorable niche by genetic modification of plant cells, a process called "genetic colonization". All stages of this colonization, including chemotaxis, attachment, induction of virulence region, processing of T-DNA, T-DNA transfer, T-DNA integration, expression of T-DNA genes and changes in the plant phenotype, will be discussed in the following chapters. This will be an odyssey of T-DNA that leaves the Agrobacterium cell in the form of nucleic acid and returns from its journey in the form of opines, derivatives of amino acids (Fig. 1).

3

Lack of correlation between X region spa polymorphism and virulence of methicillin resistant and methicillin sensitive Staphylococcus aureus strains

100%

Kurlenda J., Grinholc M., Szweda P.

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2010

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vol. 57

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issue 1

135-138

EN

Staphylococcus aureus is an etiological factor of severe infections in both hospital and ambulatory environments. As methicillin resistant Staphylococcus aureus strains spread quickly across healthcare centers resulting in life-threatening infections with increased mortality, they are considered more virulent than MSSA strains. Protein A, encoded by the spa gene, is one of the virulence factors involved in the staphylococcal pathogenesis. It has been suggested that the number of 24-bp tandem repeat units along the X region of the spa gene correlates with the virulence level of the strains. The current work analyzed the relationships between the virulence of MRSA and MSSA strains with region X polymorphism. No obvious correlation was observed.

4

Comparison of antibiotic resistance and virulence between biofilm-producing and non-producing clinical isolates of Enterococcus faecium

100%

Sieńko A., Wieczorek P., Majewski P., Ojdana D., Wieczorek A., Olszańska D., Tryniszewska E.

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2015

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vol. 62

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issue 4

859-866

EN

An increase in the antibiotic resistance among Enterococcus faecium strains has been observed worldwide. Moreover, this bacteria has the ability to produce several virulence factors and to form biofilm that plays an important role in human infections. This study was designed to compare the antibiotic resistance and the prevalence of genes encoding surface protein (esp), aggregation substance (as), surface adhesin (efaA), collagen adhesin (ace), gelatinase (gelE), and hialuronidase (hyl) between biofilm-producing and non-producing E. faecium strains. Therefore, ninety E. faecium clinical isolates were tested for biofilm-forming ability, and then were assigned to two groups: biofilm-positive (BIO+, n =70) and biofilm-negative (BIO-, n = 20). Comparison of these groups showed that BIO+ isolates were resistant to β-lactams, whereas 10% of BIO- strains were susceptible to ampicillin (statistically significant difference, p = 0.007) and 5% to imipenem. Linezolid and tigecycline were the only antibiotics active against all tested isolates. Analysis of the virulence factors revealed that ace, efaA, and gelE genes occurred more frequently in BIO- strains (ace in 50% BIO+ vs. 75% BIO-; efaA 44.3% vs. 85%; gelE 2.9% vs. 15%, respectively), while hyl gene appeared more frequently in BIO+ isolates (87.1% BIO+ vs. 65% BIO-). These differences were significant (p < 0.05). We concluded that BIO+ strains were more resistant to antibiotics than BIO- strains, but interestingly, BIO- isolates were characterized by possession of higher virulence capabilities.

5

Staphylococcus aureus as an infectious agent: overview of biochemistry and molecular genetics of its pathogenicity

88%

Plata K., Rosato A., Węgrzyn G.

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issue 4

597-612

EN

Although it is estimated that 20-30% of the general human population are carriers of Staphylococcus aureus, this bacterium is one of the most important etiological agents responsible for healthcare-associated infections. The appearance of methicillin resistant S. aureus (MRSA) strains has created serious therapeutical problems. Detailed understanding of the mechanisms of S. aureus infections seems necessary to develop new effective therapies against this pathogen. In this article, we present an overview of the biochemical and genetic mechanisms of pathogenicity of S. aureus strains. Virulence factors, organization of the genome and regulation of expression of genes involved in virulence, and mechanisms leading to methicilin resistance are presented and briefly discussed.

6

Raised plasma insulin level and homeostasis model assessment (HOMA) score in cerebral malaria: evidence for insulin resistance and marker of virulence

88%

Eltahir E. M., ElGhazali G., A-Elgadir T. M. E., A-Elbasit I. E., Elbashir M. I., Giha H. A.

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2010

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vol. 57

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issue 4

513-520

EN

Objective: To study the glycaemic profile of patients with severe malaria (SM). Methods: For this purpose, 110 SM patients were recruited. Pre-treatment random blood glucose and plasma insulin were measured in a subset of donors. An ex-vivo experiment was developed for estimation of glucose consumption by parasitized erythrocytes. Results: Hyperglycaemia was frequent in SM but more commonly associated with cerebral malaria (CM), while hyperinsulinaemia was recognized in severe-malarial-hypotension (median, 25 %-75 %, 188.2, 93.8-336.8 pmol/L). The plasma insulin level was positively correlated with age (CC = 0.457, p < 0.001) and negatively with parasitaemia (CC = -0.368, p = 0.045). Importantly, fatal-CM was associated with hyperglycaemia (12.22, 6.5-14.6 mmol/L), hyperinsulinaemia (141.0, 54.0-186.8 pmol/L) and elevated homeostasis model assessment (HOMA) values. However, there was a trend of higher glucose consumption by parasites in CM compared with that in uncomplicated malaria (UM). Conclusion: Hyperglycaemia, hyperinsulinaemia and elevated HOMA are evidence for insulin resistance and possibly pancreatic B-cell dysfunction in fatal-CM.

7

Three Pseudomonas aeruginosa strains with different protease profiles

75%

Andrejko M., Zdybicka-Barabas A., Janczarek M., Cytryńska M.

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2013

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vol. 60

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issue 1

83-90

EN

The proteolytic activity of three Pseudomonas aeruginosa strains, ATCC 27853 - a reference strain, and two clinical isolates was tested. The activity was examined after culturing the bacteria in two different growth media: the minimal M9 medium and rich Luria-Bertani broth (LB). Based on zymograms and protease activity specific assays, it was concluded that the reference strain produced three proteolytic enzymes in the LB medium: protease IV, elastase B and elastase A, while alkaline protease was only produced in the M9 medium. The clinical isolates of P. aeruginosa produced elastase B and alkaline protease when grown in the LB medium and the minimal M9 medium, respectively. PCR analysis confirmed the presence of both the lasB gene encoding elastase B and aprA coding for alkaline protease in the genomes of the three P. aeruginosa strains analyzed. The expression of these genes coding for two important P. aeruginosa virulence factors was dependent on the growth conditions in all the strains studied. The contribution of the extracellular proteinases to the virulence of P. aeruginosa strains used in this study was investigated using an insect model, the greater wax moth Galleria mellonella.

8

Melanin synthesis in microorganisms - biotechnological and medical aspects

75%

Plonka P. M., Grabacka M.

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2006

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vol. 53

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issue 3

429-443

EN

Melanins form a diverse group of pigments synthesized in living organisms in the course of hydroxylation and polymerization of organic compounds. Melanin production is observed in all large taxa from both Pro- and Eukaryota. The basic functions of melanins are still a matter of controversy and speculation, even though their adaptative importance has been proved. Melanogenesis has probably evolved paralelly in various groups of free living organisms to provide protection from environmental stress conditions, but in pathogenic microorganisms it correlates with an increased virulence. The genes responsible for melanization are collected in some cases within operons which find a versatile application in genetic engineering. This review sumarizes current views on melanogenesis in Pro- and Eukaryotic microorganisms in terms of their biotechnological and biomedical importance.

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Utilization of 4-n-nonylphenol by Metarhizium sp. isolates

Odyssey of Agrobacterium T-DNA.

Lack of correlation between X region spa polymorphism and virulence of methicillin resistant and methicillin sensitive Staphylococcus aureus strains

Comparison of antibiotic resistance and virulence between biofilm-producing and non-producing clinical isolates of Enterococcus faecium

Staphylococcus aureus as an infectious agent: overview of biochemistry and molecular genetics of its pathogenicity

Raised plasma insulin level and homeostasis model assessment (HOMA) score in cerebral malaria: evidence for insulin resistance and marker of virulence

Three Pseudomonas aeruginosa strains with different protease profiles

Melanin synthesis in microorganisms - biotechnological and medical aspects