BACKGROUND: A water-impermeable testa acts as a barrier to a seed's imbibition, thereby imposing dormancy. The physical and functional properties of the macrosclereids are thought to be critical determinants of dormancy; however, the mechanisms underlying the maintenance of and release from dormancy in pea are not well understood. METHODS: Seeds of six pea accessions of contrasting dormancy type were tested for their ability to imbibe and the permeability of their testa was evaluated. Release from dormancy was monitored following temperature oscillation, lipid removal and drying. Histochemical and microscopic approaches were used to characterize the structure of the testa. KEY RESULTS: The strophiole was identified as representing the major site for the entry of water into non-dormant seeds, while water entry into dormant seeds was distributed rather than localized. The major barrier for water uptake in dormant seeds was the upper section of the macrosclereids, referred to as the 'light line'. Dormancy could be released by thermocycling, dehydration or chloroform treatment. Assays based on either periodic acid or ruthenium red were used to visualize penetration through the testa. Lipids were detected within a subcuticular waxy layer in both dormant and non-dormant seeds. The waxy layer and the light line both formed at the same time as the establishment of secondary cell walls at the tip of the macrosclereids. CONCLUSIONS: The light line was identified as the major barrier to water penetration in dormant seeds. Its outer border abuts a waxy subcuticular layer, which is consistent with the suggestion that the light line represents the interface between two distinct environments - the waxy subcuticular layer and the cellulose-rich secondary cell wall. The mechanistic basis of dormancy break includes changes in the testa's lipid layer, along with the mechanical disruption induced by oscillation in temperature and by a decreased moisture content of the embryo.

• MeSH
• hrách setý * MeSH
• klíčení * MeSH
• semena rostlinná MeSH
• teplota MeSH
• vegetační klid MeSH
• voda MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Candidiasis now represents the fourth most frequent nosocomial infection both in the USA and worldwide. Candida albicans is an increasingly common threat to human health as a consequence of AIDS, steroid therapy, organ and tissue transplantation, cancer therapy, broad-spectrum antibiotics, and other immune defects. Unfortunately, these infections carry unacceptably high morbidity, mortality rates and important economic repercussions (estimated total direct cost of approximately 2 billion dollars in 1998 in US hospitals alone). This pathogen can grow both in yeast and filamentous forms and the pathogenic potential of C. albicans is intimately related to certain key processes including filamentation. Chlamydospores are considered to be a dormant form of C. albicans that remain understudied. Chlamydospores have been widely used as a diagnostic tool to separate C. albicans and C. dubliniensis from other Candida species. More recently, media have been developed that use chlamydopsore formation to separate C. albicans and C. dubliniensis from each other. Chlamydospore formation can be stimulated by hypoxic conditions but only on limited specific media types. Here, we show that anaerobic conditions are enough to drive chlamydospore formation in C. albicans on the surface of nutrient-rich agar.

• MeSH
• anaerobióza MeSH
• Candida albicans * MeSH
• Candida MeSH
• kandidóza * MeSH
• kultivační média MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The complex development undergone by Streptomyces encompasses transitions from vegetative mycelial forms to reproductive aerial hyphae that differentiate into chains of single-celled spores. Whereas their mycelial life - connected with spore formation and antibiotic production - is deeply investigated, spore germination as the counterpoint in their life cycle has received much less attention. Still, germination represents a system of transformation from metabolic zero point to a new living lap. There are several aspects of germination that may attract our attention: (1) Dormant spores are strikingly well-prepared for the future metabolic restart; they possess stable transcriptome, hydrolytic enzymes, chaperones, and other required macromolecules stabilized in a trehalose milieu; (2) Germination itself is a specific sequence of events leading to a complete morphological remodeling that include spore swelling, cell wall reconstruction, and eventually germ tube emergences; (3) Still not fully unveiled are the strategies that enable the process, including a single cell's signal transduction and gene expression control, as well as intercellular communication and the probability of germination across the whole population. This review summarizes our current knowledge about the germination process in Streptomyces, while focusing on the aforementioned points.

• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The survival of spirochetes from the Borrelia burgdorferi (sensu lato) complex in a hostile environment is achieved by the regulation of differential gene expression in response to changes in temperature, salts, nutrient content, acidity fluctuation, multiple host or vector dependent factors, and leads to the formation of dormant subpopulations of cells. From the other side, alterations in the level of gene expression in response to antibiotic pressure leads to the establishment of a persisters subpopulation. Both subpopulations represent the cells in different physiological states. "Dormancy" and "persistence" do share some similarities, e.g. both represent cells with low metabolic activity that can exist for extended periods without replication, both constitute populations with different gene expression profiles and both differ significantly from replicating forms of spirochetes. Persisters are elusive, present in low numbers, morphologically heterogeneous, multi-drug-tolerant cells that can change with the environment. The definition of "persisters" substituted the originally-used term "survivors", referring to the small bacterial population of Staphylococcus that survived killing by penicillin. The phenomenon of persisters is present in almost all bacterial species; however, the reasons why Borrelia persisters form are poorly understood. Persisters can adopt varying sizes and shapes, changing from well-known forms to altered morphologies. They are capable of forming round bodies, L-form bacteria, microcolonies or biofilms-like aggregates, which remarkably change the response of Borrelia to hostile environments. Persisters remain viable despite aggressive antibiotic challenge and are able to reversibly convert into motile forms in a favorable growth environment. Persisters are present in significant numbers in biofilms, which has led to the explanation of biofilm tolerance to antibiotics. Considering that biofilms are associated with numerous chronic diseases through their resilient presence in the human body, it is not surprising that interest in persisting cells has consequently accelerated. Certain diseases caused by pathogenic bacteria (e.g. tuberculosis, syphilis or leprosy) are commonly chronic in nature and often recur despite antibiotic treatment. Three decades of basic and clinical research have not yet provided a definite answer to the question: is there a connection between persisting spirochetes and recurrence of Lyme disease in patients?

• MeSH
• antibakteriální látky farmakologie   MeSH
• biofilmy růst a vývoj   MeSH
• Borrelia burgdorferi komplex účinky léků   fyziologie   MeSH
• lidé MeSH
• lymeská nemoc mikrobiologie   MeSH
• mikrobiální viabilita účinky léků   MeSH
• recidiva MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

In the absence of transcription, the regulation of gene expression in oocytes is controlled almost exclusively at the level of transcriptome and proteome stabilization, and translation. A subset of maternal transcripts is stored in a translationally dormant state in the oocyte, and temporally driven translation of specific mRNAs propel meiotic progression, oocyte-to-embryo transition and early embryo development. We identified Ank2.3 as the only transcript variant present in the mouse oocyte and discovered that it is translated after nuclear envelope breakdown. Here we show that Ank2.3 mRNA is localized in higher concentration in the oocyte nucleoplasm and, after nuclear envelope breakdown, in the newly forming spindle where its translation occurs. Furthermore, we reveal that Ank2.3 mRNA contains an oligo-pyrimidine motif at 5'UTR that predetermines its translation through a cap-dependent pathway. Lastly, we show that prevention of ANK2 translation leads to abnormalities in oocyte cytokinesis.

• MeSH
• ankyriny genetika   metabolismus   MeSH
• časoprostorová analýza * MeSH
• cytokineze * MeSH
• embryo savčí cytologie   fyziologie   MeSH
• meióza * MeSH
• messenger RNA genetika   metabolismus   MeSH
• myši MeSH
• oocyty cytologie   fyziologie   MeSH
• oogeneze MeSH
• vývojová regulace genové exprese * MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Muž ve věku 74 let s diabetes mellitus 2. typu, ischemickou chorobou srdeční po operaci aortokoronárního bypassu, hypertenzí a chronickou bronchitidou měl před 5 lety implantovánu náhradu levého kyčelního kloubu na jiném pracovišti. Již od časného pooperačního období jevil známky mitigovaného infektu, který byl empiricky přeléčován antibiotiky. Při současné hospitalizaci byly na rentgenovém snímku patrné známky uvolnění komponent TEP s výraznou kostní resorpcí. Periprotetický infekt byl řešen dvoudobě. V první fázi byla extrahována infikovaná kloubní protéza a byla nahrazena dočasným spacerem napuštěným antibiotiky. Za měsíc byla provedena reimplantace revizní endoprotézy s použitím cementu s antibiotiky. Z materiálu extrahovaného během první operace byla kultivována masivně Listeria monocytogenes a ojediněle Staphylococcus epidermidis. jedná se o 18. publikovanou kazuistiku listeriové infekce umělé kloubní náhrady. V případě referovaného pacienta se patrně jednalo o mitigovaný stafylokokový infekt, na který hematogenně nasedla listeriová infekce, která odloučení protézy výrazně urychlila. Přehled literatury ukazuje na několik vlastností listerií, které činí konzervativní léčbu obtížnou, především výrazná stimulace imunitního systému (s výslednou destrukcí okolních tkání), přežívání v makrofázích (nedosažitelnost pro antibiotika účinná in vitro) a schopnost vytvářet biofilm i osidlovat biofilm vytvořený jinými bakteriemi. Větší výtěžnost a spolehlivost mikrobiologických vyšetření lze dosáhnout díky navigované punkci z mikroincize před operací, prodlouženou dobou kultivace a dále sonifikací extrahovaného materiálu, dvoudobým operačním přístupem a kontrolní punkcí se zhodnocením počtu leukocytů v kloubní dutině před reimplantací nové protézy.

A 74-year-old male with type 2 diabetes, coronary artery disease with history of CABG, hypertension and chronic obstructive pulmonary disease had total left hip replacement in another medical facility five years prior to admission. Since the early postoperative period, he had manifestations of dormant infection and was with empirical antibiotics. On the index admission, his X-ray showed signs of loosening of the prosthetic components with resorption of the bone. Periprosthetic infection was managed by a two-stage surgery. First, the infected prosthesis was removed and replaced with a spacer with antibiotics. One month later, a revision prosthesis, was implanted using cement with antibiotics. Cultures of the excised tissues and materials yielded massive growth of Listeria monocytogenes and scarce growth of Staphylococcus epidermidis. This is the 18th published case of arthroplasty infection caused by Listeria. The presented patient most likely had dormant staphylococcal infection on which Listeria superinfection developed and accelerated the loosening. A literature review suggested several mechanisms that can make conservative management of Listeria infection difficult. They include marked stimulation of the immune system (with resulting resorption of the bone), survival in the macrophages (unavailability to antibiotics susceptible in vitro) and capability to form biofilm as well as settle in biofilms produced by other organisms. Better yield and reliability of microbiological investigations may be achieved by guided intrarticular fluid aspiration from a microincision, prolonged culture and sonification of the extracted material, two-step surgical management and follow-up intraarticular fluid aspiration prior to reimplantation of revision prosthesis.

• Klíčová slova
• periprotetický infekt, listeriosis,
• MeSH
• infekce spojené s protézou diagnóza   chirurgie   MeSH
• kyčelní protézy škodlivé účinky   MeSH
• lidé MeSH
• Listeria monocytogenes MeSH
• listeriové infekce diagnóza   chirurgie   MeSH
• odstranění implantátu MeSH
• senioři MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• Publikační typ
• kazuistiky MeSH

Differentiation into infectious cysts (encystation) and multiplication of pathogenic trophozoites after hatching from the cyst (excystation) are fundamental processes in the life cycle of the human intestinal parasite Giardia intestinalis. During encystation, a bi-nucleated trophozoite transforms to a dormant tetra-nucleated cyst enveloped by a protective cyst wall. Nuclear division during encystation is not followed by cytokinesis. In contrast to the well-studied mechanism of cyst wall formation, information on nuclei behavior is incomplete and basic cytological data are lacking. Here we present evidence that (1) the nuclei divide by semi-open mitosis during early encystment; (2) the daughter nuclei coming from different parent nuclei are always arranged in pairs; (3) in both pairs, the nuclei are interconnected via bridges formed by fusion of their nuclear envelopes; (4) each interconnected nuclear pair is associated with one basal body tetrad of the undivided diplomonad mastigont; and (5) the interconnection between nuclei persists through the cyst stage being a characteristic feature of encysted Giardia. Based on the presented results, a model of nuclei behavior during Giardia differentiation is proposed.

• MeSH
• buněčná diferenciace MeSH
• buněčné jádro genetika   MeSH
• Giardia cytologie   genetika   růst a vývoj   MeSH
• giardiáza parazitologie   MeSH
• lidé MeSH
• mitóza MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A key objective in immuno-oncology is to reactivate the dormant immune system and increase tumour immunogenicity. Adenosine is an omnipresent purine that is formed in response to stress stimuli in order to restore physiological balance, mainly via anti-inflammatory, tissue-protective, and anti-nociceptive mechanisms. Adenosine overproduction occurs in all stages of tumorigenesis, from the initial inflammation/local tissue damage to the precancerous niche and the developed tumour, making the adenosinergic pathway an attractive but challenging therapeutic target. Many current efforts in immuno-oncology are focused on restoring immunosurveillance, largely by blocking adenosine-producing enzymes in the tumour microenvironment (TME) and adenosine receptors on immune cells either alone or combined with chemotherapy and/or immunotherapy. However, the effects of adenosinergic immunotherapy are not restricted to immune cells; other cells in the TME including cancer and stromal cells are also affected. Here we summarise recent advancements in the understanding of the tumour adenosinergic system and highlight the impact of current and prospective immunomodulatory therapies on other cell types within the TME, focusing on adenosine receptors in tumour cells. In addition, we evaluate the structure- and context-related limitations of targeting this pathway and highlight avenues that could possibly be exploited in future adenosinergic therapies.

• MeSH
• adenosin biosyntéza   genetika   imunologie   terapeutické užití   MeSH
• cílená molekulární terapie * MeSH
• imunoterapie trendy   MeSH
• karcinogeneze účinky léků   imunologie   MeSH
• lidé MeSH
• nádorové mikroprostředí účinky léků   imunologie   MeSH
• nádory genetika   imunologie   terapie   MeSH
• purinergní receptory P1 imunologie   terapeutické užití   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The oocyte-to-embryo transition (OET) transforms a differentiated gamete into pluripotent blastomeres. The accompanying maternal-zygotic RNA exchange involves remodeling of the long non-coding RNA (lncRNA) pool. Here, we used next generation sequencing and de novo transcript assembly to define the core population of 1,600 lncRNAs expressed during the OET (lncRNAs). Relative to mRNAs, OET lncRNAs were less expressed and had shorter transcripts, mainly due to fewer exons and shorter 5' terminal exons. Approximately half of OET lncRNA promoters originated in retrotransposons suggesting their recent emergence. Except for a small group of ubiquitous lncRNAs, maternal and zygotic lncRNAs formed two distinct populations. The bulk of maternal lncRNAs was degraded before the zygotic genome activation. Interestingly, maternal lncRNAs seemed to undergo cytoplasmic polyadenylation observed for dormant mRNAs. We also identified lncRNAs giving rise to trans-acting short interfering RNAs, which represent a novel lncRNA category. Altogether, we defined the core OET lncRNA transcriptome and characterized its remodeling during early development. Our results are consistent with the notion that rapidly evolving lncRNAs constitute signatures of cells-of-origin while a minority plays an active role in control of gene expression across OET. Our data presented here provide an excellent source for further OET lncRNA studies.

• MeSH
• blastomery metabolismus   MeSH
• embryo savčí metabolismus   MeSH
• myši MeSH
• oocyty metabolismus   MeSH
• RNA dlouhá nekódující genetika   metabolismus   MeSH
• sekvenční analýza RNA MeSH
• stanovení celkové genové exprese MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• vývojová regulace genové exprese * MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Fourteen blue-green and green algae survived for widely different time periods ranging between 22-102 d in control culture medium. Irrespective of their long or short survival period in control cultures, their pro- or eukaryotic nature, their different morphological types or natural habitats, they all survived for a short time period ranging between 3-8 d in sewage water, 5-10 d in fertilizer factory effluent, (1/4)-2 d in brassica oil, (1/2)-2 d in phenol, 1-3 d in toluene, and 1-4 d in benzene (showing the relative toxicity of different chemicals to different algae, and the antialgal nature of brassica oil). Dilution decreased the toxicity of these agents very little, indicating that they all were very toxic to algae. None of the agent induced the formation of any reproductive or dormant cells. Sewage water, fertilizer factory effluent, brassica oil and/or benzene favored the formation of necridia cells in Phormidium bohneri, P. foveolarum, Microcoleus chthonoplastes, Lyngbya birgei, and L. major filaments. Scenedesmus quadricauda shed off all spines earlier, Hormidium flaccidum fragmented less or not at all, Scytonema millei formed no false branch and heterocyst, Aphanothece pallida and Gloeocapsa atrata cells did not divide, Cosmarium granatum cells did not form any zygospore and Oedogonium sp. not any oogonia-like cells under all or most of treatments with 25-100 % sewage water, 1-100 % fertilizer factory effluent, 1-100 % brassica oil, 25-100 % phenol, toluene and benzene.

• MeSH
• benzen farmakologie   MeSH
• chemické látky znečišťující vodu farmakologie   MeSH
• Chlorophyta fyziologie   účinky léků   MeSH
• fenol farmakologie   MeSH
• odpadní vody analýza   MeSH
• organické látky farmakologie   MeSH
• průmyslový odpad analýza   MeSH
• rozmnožování účinky léků   MeSH
• spory fyziologie   účinky léků   MeSH
• toluen farmakologie   MeSH