Chlamydial plasmids and bacteriophages

Chlamydia are absolute pathogens of humans and animals; despite being rather well recognised, they are still open for discovery. One such discovery is the occurrence of extrachromosomal carriers of genetic information. In prokaryotes, such carriers include plasmids and bacteriophages, which are present only among some Chlamydia species. Plasmids were found exclusively in Chlamydia (C.) trachomatis, C. psittaci, C. pneumoniae, C. suis, C. felis, C. muridarum and C. caviae. In prokaryotic organisms, plasmids usually code for genes that facilitate survival of the bacteria in the environment (although they are not essential). In chlamydia, their role has not been definitely recognised, apart from the fact that they participate in the synthesis of glycogen and encode proteins responsible for their virulence. Furthermore, in C. suis it was evidenced that the plasmid is integrated in a genomic island and contains the tetracycline-resistance gene. Bacteriophages specific for chlamydia (chlamydiaphages) were detected only in six species: C. psittaci, C. abortus, C. felis, C. caviae C. pecorum and C. pneumoniae. These chlamydiaphages cause inhibition of the developmental cycle, and delay transformation of reticulate bodies (RBs) into elementary bodies (EBs), thus reducing the possibility of infecting other cells in time. Plasmids and bacteriophages can be used in the diagnostics of chlamydioses; although especially in the case of plasmids, they are already used for detection of chlamydial infections. In addition, bacteriophages could be used as therapeutic agents to replace antibiotics, potentially addressing the problem of increasing antibiotic-resistance among chlamydia

mRNA Regulatory elements and bacterial virulence

Pathogenic bacteria cause many diseases, some of which are fatal. For researchers, it is a challenge to understand bacterial mechanisms of pathogenicity, including their virulence pathways regulated by RNA. This work presents data on the mechanisms of regulation and expression of several virulence factors coded by RNA, namely 5' UTR fragments, riboswitches and small non-coding RNA (sRNA)

Chlamydial plasmids and bacteriophages

Chlamydia are absolute pathogens of humans and animals; despite being rather well recognised, they are still open for discovery. One such discovery is the occurrence of extrachromosomal carriers of genetic information. In prokaryotes, such carriers include plasmids and bacteriophages, which are present only among some Chlamydia species. Plasmids were found exclusively in Chlamydia (C.) trachomatis, C. psittaci, C. pneumoniae, C. suis, C. felis, C. muridarum and C. caviae. In prokaryotic organisms, plasmids usually code for genes that facilitate survival of the bacteria in the environment (although they are not essential). In chlamydia, their role has not been definitely recognised, apart from the fact that they participate in the synthesis of glycogen and encode proteins responsible for their virulence. Furthermore, in C. suis it was evidenced that the plasmid is integrated in a genomic island and contains the tetracycline-resistance gene. Bacteriophages specific for chlamydia (chlamydiaphages) were detected only in six species: C. psittaci, C. abortus, C. felis, C. caviae C. pecorum and C. pneumoniae. These chlamydiaphages cause inhibition of the developmental cycle, and delay transformation of reticulate bodies (RBs) into elementary bodies (EBs), thus reducing the possibility of infecting other cells in time. Plasmids and bacteriophages can be used in the diagnostics of chlamydioses; although especially in the case of plasmids, they are already used for detection of chlamydial infections. In addition, bacteriophages could be used as therapeutic agents to replace antibiotics, potentially addressing the problem of increasing antibiotic-resistance among chlamydia

Biofilm and Quorum Sensing in Archaea

In the article, we presented a brief description of the Archaea, considering their structure, physiology and systematics. Based on the analysis of the literature, we bring closer the mechanism of biofilm formation, including extracellular polymeric substances as well as cellular organelles, such as archaella, pili and ‘hami’. The method of forming a biofilm depends on the type of Archaea and the environment in which it naturally lives. We are also introducing the phenomenon of quorum-sensing, as a mechanism of communication of Archaea in the environment. This phenomenon corresponds to similar molecules as bacteria, namely acylated homoserines lactones, QS peptides, autoinducer-2 and -3 and others. In the case of biofilms and the occurrence of the phenomenon of quorum sensing, it can be concluded that these phenomena are very important for the life of Archaea. The phenomena described seem to be conservative, because both in Archaea and Bacteria are regulated by the same mechanisms.W artykule przedstawiamy opis Archaea, z uwzględnieniem ich budowy, fizjologii i systema- tyki. Na podstawie piśmiennictwa przybliżamy mechanizm tworzenia biofilmu wraz z poza-komórkowymi substancjami polimerowymi, a także typowe tylko dla archeonów organelle komórkowe, takie jak archaella, pili i „hami”. Metoda tworzenia biofilmu zależy od rodzaju Archaea i środowiska, w którym naturalnie żyje. Przybliżamy również zjawisko quorum--sensing, jako mechanizm komunikacji Archaea w środowisku. Za zjawisko to odpowiadają cząsteczki chemiczne podobne do tych u bakterii, a mianowicie acylowany lakton homoseryny, peptyd QS, autoinduktor-2 i -3 oraz inne. Opisywane zjawiska, zarówno tworzenie biofilmu jak i quorum-sensing są istotne dla życia archeonów. Opisane zjawiska wydają się konserwatywne, ponieważ zarówno u archeonów, jak i bakterii są regulowane przez te same mechanizmy

Somatic and F-specific bacteriophages in waters of the small, municipal Rusałka Lake in Szczecin

Investigations of bacteriophages showed that in the environment are mostly in water, but in small municipal lakes sporadically been studied. Previous studies of bacteriophages in the aqueous environment related to the determination of the quantity and diversity and use them as indicators of water pollution. In the last study probably of the most important are the F-specific and somatic bacteriophages specific to E. coli. In our study examined them in a small municipal lake in Szczecin (Poland) in context of occurrence of F-specific and somatic bacteriophages specific to E. coli with used of SAL method. We proved that count of bacteriophages in this water tank is lower in context of different waters, but the relation between the amounts of this viruses and environments condition (air and water temperature) were similar to results observed in waters of seas, rivers and lakes.Badania bakteriofagów wykazały, że w środowisku naturalnym znajdują się one głównie w wodzie, ale w małych jeziorach miejskich badano je sporadycznie. Poprzednie badania bakteriofagów w środowisku wodnym dotyczyły określania ilości i różnorodności oraz wykorzystywania ich jako wskaźników zanieczyszczenia wody. Wcześniejsze badania wykazały, że prawdopodobnie najważniejszymi są F-specyficzne i somatyczne bakteriofagi E. coli. W obecnym badaniu oznaczaliśmy je w małym jeziorze miejskim w Szczecinie (Polska), za pomocą metody SAL. Udowodniliśmy, że liczba bakteriofagów w tym zbiorniku jest mniejsza w porównaniu do innych wód, ale związek między liczbą tych wirusów a warunkami środowiska (temperatura powietrza i wody) był podobny do wyników obserwowanych w wodach mórz, rzek i jezior