BACKGROUND: Seedling recruitment is essential to the sustainability of any plant population. Due to the minute nature of seeds and early-stage seedlings, orchid germination in situ was for a long time practically impossible to observe, creating an obstacle towards understanding seedling site requirements and fluctuations in orchid populations. The introduction of seed packet techniques for sowing and retrieval in natural sites has brought with it important insights, but many aspects of orchid seed and germination biology remain largely unexplored. KEY CONSIDERATIONS: The germination niche for orchids is extremely complex, because it is defined by requirements not only for seed lodging and germination, but also for presence of a fungal host and its substrate. A mycobiont that the seedling can parasitize is considered an essential element, and a great diversity of Basidiomycota and Ascomycota have now been identified for their role in orchid seed germination, with fungi identifiable as imperfect Rhizoctonia species predominating. Specificity patterns vary from orchid species employing a single fungal lineage to species associating individually with a limited selection of distantly related fungi. A suitable organic carbon source for the mycobiont constitutes another key requirement. Orchid germination also relies on factors that generally influence the success of plant seeds, both abiotic, such as light/shade, moisture, substrate chemistry and texture, and biotic, such as competitors and antagonists. Complexity is furthermore increased when these factors influence seeds/seedling, fungi and fungal substrate differentially. CONCLUSIONS: A better understanding of germination and seedling establishment is needed for conservation of orchid populations. Due to the obligate association with a mycobiont, the germination niches in orchid species are extremely complex and varied. Microsites suitable for germination can be small and transient, and direct observation is difficult. An experimental approach using several levels of environmental manipulation/control is recommended.

• MeSH
• klíčení * MeSH
• Orchidaceae růst a vývoj   mikrobiologie   MeSH
• semenáček růst a vývoj   mikrobiologie   MeSH
• zachování přírodních zdrojů * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

An example of bacterium, which undergoes a complex development, is the genus of Streptomyces whose importance lies in their wide capacity to produce secondary metabolites, including antibiotics. In this work, a proteomic approach was applied to the systems study of germination as a transition from dormancy to the metabolically active stage. The protein expression levels were examined throughout the germination time course, the kinetics of the accumulated and newly synthesized proteins were clustered, and proteins detected in each group were identified. Altogether, 104 2DE gel images at 13 time points, from dormant state until 5.5 h of growth, were analyzed. The mass spectrometry identified proteins were separated into functional groups and their potential roles during germination were further assessed. The results showed that the full competence of spores to effectively undergo active metabolism is derived from the sporulation step, which facilitates the rapid initiation of global protein expression during the first 10 min of cultivation. Within the first hour, the majority of proteins were synthesized. From this stage, the full capability of regulatory mechanisms to respond to environmental cues is presumed. The obtained results might also provide a data source for further investigations of the process of germination.

• MeSH
• 2D gelová elektroforéza MeSH
• antibakteriální látky biosyntéza   MeSH
• hmotnostní spektrometrie MeSH
• proteom analýza   MeSH
• proteosyntéza * MeSH
• regulace genové exprese u bakterií MeSH
• spory bakteriální * růst a vývoj   metabolismus   MeSH
• Streptomyces coelicolor * genetika   růst a vývoj   metabolismus   MeSH
• vývojová regulace genové exprese MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Aurora kinase A (AURKA), which is a centrosome-localized serine/threonine kinase crucial for cell cycle control, is critically involved in centrosome maturation and spindle assembly in somatic cells. Active T288 phosphorylated AURKA localizes to the centrosome in the late G(2) and also spreads to the minus ends of mitotic spindle microtubules. AURKA activates centrosomal CDC25B and recruits cyclin B1 to centrosomes. We report here functions for AURKA in meiotic maturation of mouse oocytes, which is a model system to study the G(2) to M transition. Whereas AURKA is present throughout the entire GV-stage oocyte with a clear accumulation on microtubule organizing centers (MTOC), active AURKA becomes entirely localized to MTOCs shortly before germinal vesicle breakdown. In contrast to somatic cells in which active AURKA is present at the centrosomes and minus ends of microtubules, active AURKA is mainly located on MTOCs at metaphase I (MI) in oocytes. Inhibitor studies using Roscovitine (CDK1 inhibitor), LY-294002 (PI3K inhibitor) and SH-6 (PKB inhibitor) reveal that activation of AURKA localized on MTOCs is independent on PI3K-PKB and CDK1 signaling pathways and MOTC amplification is observed in roscovitine- and SH-6-treated oocytes that fail to undergo nuclear envelope breakdown. Moreover, microinjection of Aurka mRNA into GV-stage oocytes cultured in 3-isobutyl-1-methyl xanthine (IBMX)-containing medium to prevent maturation also results in MOTC amplification in the absence of CDK1 activation. Overexpression of AURKA also leads to formation of an abnormal MI spindle, whereas RNAi-mediated reduction of AURKA interferes with resumption of meiosis and spindle assembly. Results of these experiments indicate that AURKA is a critical MTOC-associated component involved in resumption of meiosis, MTOC multiplication, proper spindle formation and the metaphase I-metaphase II transition.

• MeSH
• aparát dělícího vřeténka metabolismus   MeSH
• blastodisk metabolismus   MeSH
• buněčný cyklus fyziologie   genetika   MeSH
• buňky NIH 3T3 MeSH
• cyklin-dependentní kinasy fyziologie   metabolismus   MeSH
• financování organizované MeSH
• HeLa buňky MeSH
• lidé MeSH
• meióza fyziologie   genetika   MeSH
• myši inbrední BALB C MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• oocyty enzymologie   fyziologie   MeSH
• organizační centrum mikrotubulů metabolismus   MeSH
• protein-serin-threoninkinasy fyziologie   genetika   metabolismus   MeSH
• protoonkogenní proteiny c-akt fyziologie   metabolismus   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH

• MeSH
• námelové alkaloidy MeSH
• Publikační typ
• monografie MeSH

• Konspekt
• Biochemie. Molekulární biologie. Biofyzika
• NLK Obory
• biochemie
• fyziologie
• farmacie a farmakologie

Polarized exocytosis is critical for pollen tube growth, but its localization and function are still under debate. The exocyst vesicle-tethering complex functions in polarized exocytosis. Here, we show that a sec3a exocyst subunit null mutant cannot be transmitted through the male gametophyte due to a defect in pollen tube growth. The green fluorescent protein (GFP)-SEC3a fusion protein is functional and accumulates at or proximal to the pollen tube tip plasma membrane. Partial complementation of sec3a resulted in the development of pollen with multiple tips, indicating that SEC3 is required to determine the site of pollen germination pore formation. Time-lapse imaging demonstrated that SEC3a and SEC8 were highly dynamic and that SEC3a localization on the apical plasma membrane predicts the direction of growth. At the tip, polar SEC3a domains coincided with cell wall deposition. Labeling of GFP-SEC3a-expressing pollen with the endocytic marker FM4-64 revealed the presence of subdomains on the apical membrane characterized by extensive exocytosis. In steady-state growing tobacco (Nicotiana tabacum) pollen tubes, SEC3a displayed amino-terminal Pleckstrin homology-like domain (SEC3a-N)-dependent subapical membrane localization. In agreement, SEC3a-N interacted with phosphoinositides in vitro and colocalized with a phosphatidylinositol 4,5-bisphosphate (PIP2) marker in pollen tubes. Correspondingly, molecular dynamics simulations indicated that SEC3a-N associates with the membrane by interacting with PIP2 However, the interaction with PIP2 is not required for polar localization and the function of SEC3a in Arabidopsis (Arabidopsis thaliana). Taken together, our findings indicate that SEC3a is a critical determinant of polar exocytosis during tip growth and suggest differential regulation of the exocytotic machinery depending on pollen tube growth modes.

• MeSH
• Arabidopsis genetika   růst a vývoj   metabolismus   MeSH
• buněčná membrána metabolismus   MeSH
• časosběrné zobrazování metody   MeSH
• exocytóza * MeSH
• fosfatidylinositol-4,5-difosfát metabolismus   MeSH
• fosfatidylinositoly metabolismus   MeSH
• fylogeneze MeSH
• geneticky modifikované rostliny MeSH
• konfokální mikroskopie MeSH
• mutace MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• protein - isoformy genetika   metabolismus   MeSH
• proteiny huseníčku klasifikace   genetika   metabolismus   MeSH
• pyl genetika   růst a vývoj   metabolismus   MeSH
• pylová láčka genetika   růst a vývoj   metabolismus   MeSH
• sekvence aminokyselin MeSH
• sekvence nukleotidů MeSH
• sekvenční homologie aminokyselin MeSH
• sekvenční homologie nukleových kyselin MeSH
• simulace molekulární dynamiky MeSH
• stanovení celkové genové exprese metody   MeSH
• vazba proteinů MeSH
• vazebná místa genetika   MeSH
• vezikulární transportní proteiny klasifikace   genetika   metabolismus   MeSH
• zelené fluorescenční proteiny genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH

Cellular homeostasis of S-nitrosoglutathione (GSNO), a major cache of nitric oxide bioactivity in plants, is controlled by the NADH-dependent S-nitrosoglutathione reductase (GSNOR) belonging to the family of class III alcohol dehydrogenases (EC 1.1.1.1). GSNOR is a key regulator of S-nitrosothiol metabolism and is involved in plant responses to abiotic and biotic stresses. This study was focused on GSNOR from two important crop plants, cauliflower (Brassica oleracea var. botrytis, BoGSNOR) and lettuce (Lactuca sativa, LsGSNOR). Both purified recombinant GSNORs were characterized in vitro and found to exists as dimers, exhibit high thermal stability and substrate preference towards GSNO, although both enzymes have dehydrogenase activity with a broad range of long-chain alcohols and ω-hydroxy fatty acids in presence of NAD+. Data on enzyme affinities to their cofactors NADH and NAD+ obtained by isothermal titration calorimetry suggest the high affinity to NADH might underline the GSNOR capacity to function in the intracellular environment. GSNOR activity and gene expression peak during early developmental stages of lettuce and cauliflower at 20 and 30 days after germination, respectively. GSNOR activity was also measured in four other Lactuca spp. genotypes with different degree of resistance to biotrophic pathogen Bremia lactucae. Higher GSNOR activities were found in non-infected plants of susceptible genotypes L. sativa UCDM2 and L. serriola as compared to resistant genotypes. GSNOR and GSNO were localized by confocal laser scanning microscopy in vascular bundles and in epidermal and parenchymal cells of leaf cross-sections. The presented results bring new insight in the role of GSNOR in the regulation of S-nitrosothiol levels in plant growth and development.

• MeSH
• aldehydoxidoreduktasy genetika   metabolismus   MeSH
• Brassica enzymologie   genetika   růst a vývoj   MeSH
• genotyp MeSH
• oxidoreduktasy genetika   metabolismus   MeSH
• salát (hlávkový) enzymologie   genetika   růst a vývoj   MeSH
• vývoj rostlin fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH

Chronic lymphocytic leukemia is a disease with up-regulated expression of the transmembrane tyrosine-protein kinase ROR1, a member of the Wnt/planar cell polarity pathway. In this study, we identified COBLL1 as a novel interaction partner of ROR1. COBLL1 shows clear bimodal expression with high levels in chronic lymphocytic leukemia patients with mutated IGHV and approximately 30% of chronic lymphocytic leukemia patients with unmutated IGHV. In the remaining 70% of chronic lymphocytic leukemia patients with unmutated IGHV, COBLL1 expression is low. Importantly, chronic lymphocytic leukemia patients with unmutated IGHV and high COBLL1 have an unfavorable disease course with short overall survival and time to second treatment. COBLL1 serves as an independent molecular marker for overall survival in chronic lymphocytic leukemia patients with unmutated IGHV. In addition, chronic lymphocytic leukemia patients with unmutated IGHV and high COBLL1 show impaired motility and chemotaxis towards CCL19 and CXCL12 as well as enhanced B-cell receptor signaling pathway activation demonstrated by increased PLCγ2 and SYK phosphorylation after IgM stimulation. COBLL1 expression also changes during B-cell maturation in non-malignant secondary lymphoid tissue with a higher expression in germinal center B cells than naïve and memory B cells. Our data thus suggest COBLL1 involvement not only in chronic lymphocytic leukemia but also in B-cell development. In summary, we show that expression of COBLL1, encoding novel ROR1-binding partner, defines chronic lymphocytic leukemia subgroups with a distinct response to microenvironmental stimuli, and independently predicts survival of chronic lymphocytic leukemia with unmutated IGHV.

• MeSH
• analýza přežití MeSH
• chronická lymfatická leukemie klasifikace   diagnóza   genetika   mortalita   MeSH
• lidé MeSH
• mutace MeSH
• pohyb buněk MeSH
• polarita buněk MeSH
• prognóza MeSH
• signální dráha Wnt MeSH
• sirotčí receptory podobné receptoru tyrosinkinasy metabolismus   MeSH
• těžké řetězce imunoglobulinů genetika   MeSH
• transkripční faktory metabolismus   MeSH
• variabilní oblast imunoglobulinu genetika   MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

This study aimed to investigate the effect of phenylhydrazine-induced hemolytic anemia on testicular functions and protective role of crocin in mice. Forty-nine adult male mice were studied in 7 groups. The control mice received normal saline, three groups were treated with 2, 4, and 6 mg/100 g of phenylhydrazine, and three other groups received 20 mg/100 g of crocin with phenylhydrazine for 35 days. Then, the blood samples were taken to examine oxidative stress of serum, sperm samples were obtained for IVF testing, and testicle tissue samples were taken for morphological studies. Morphometric results indicated a significant reduction in TDI (tubular differentiation index), RI (repopulation index or number of type B spermatogonia), and SI (spermiogenesis index) factors, number of Sertoli and Leydig cells, and diameter of germinal epithelium in the groups receiving phenylhydrazine. Histochemical results indicated some changes in the metabolic cycle of the testicle and results of serum tests showed variations in the peroxidation of lipids and antioxidant capacity of serum. Also, hemolytic anemia significantly reduced testicular parameters and crocin minimized the resulting injuries. It can be concluded that crocin is able to neutralize the complications which are resulting from the hemolytic anemia relating to testicular parameters.

• MeSH
• biologie buňky MeSH
• experimenty na zvířatech MeSH
• fenylhydraziny aplikace a dávkování   škodlivé účinky   MeSH
• fertilita * imunologie   účinky léků   MeSH
• hemolytické anemie * farmakoterapie   chemicky indukované   prevence a kontrola   MeSH
• karotenoidy * aplikace a dávkování   terapeutické užití   MeSH
• Leydigovy buňky účinky léků   MeSH
• myši MeSH
• oxidační stres genetika   imunologie   účinky léků   MeSH
• rozmnožování genetika   imunologie   účinky léků   MeSH
• Sertoliho buňky účinky léků   MeSH
• statistika jako téma MeSH
• testis imunologie   účinky léků   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

Maturation of trematode larval stages is expected to be temporally and spatially adapted to maximise the encounter with the adequate downstream host, i.e. the host, which will be infected by this parasite stage. Since studies on intramolluscan parasite maturation are scarce but important in the context of parasite transmission, the larval development inside sporocysts was monitored during upshore residency of the snail host Gibbula adansonii (Trochidae), i.e., from March to May (2011 and 2013), when these snails temporarily reside in the intertidal habitat of a Western Mediterranean lagoon (40° 37' 35′′ N, 0° 44' 31′′ E, Spain). Data on the relative quantity of different maturation stages of Cainocreadium labracis and Macvicaria obovata (Opecoelidae) parasitising the G. adansonii as well as on snail and sporocyst size were explored using linear models and linear mixed models. The effect of the trematodes on snail growth was shown to be species-specific, with snail and sporocyst size acting as proxies of the reproductive capacity of M. obovata but not that of C. labracis. The number of cercarial embryos and germinal balls did not show monthly variation in either parasite species, but a higher number of mature stages and the highest maturity index was found in April. Hence, during the snail's limited spawning-related presence in the upshore waters of the lagoon, continuous production and output of infectious cercariae was observed, which indicates a link between larval maturation and snail migration. The synchronization of snails, mature parasite transmission stages and downstream hosts in time and space guarantees a successful completion of the life cycle.

• MeSH
• cerkárie růst a vývoj   MeSH
• druhová specificita MeSH
• ekosystém MeSH
• hlemýždi parazitologie   MeSH
• interakce hostitele a parazita MeSH
• larva růst a vývoj   MeSH
• lineární modely MeSH
• migrace zvířat MeSH
• mořská voda MeSH
• oocysty MeSH
• roční období MeSH
• rozmnožování MeSH
• stadia vývoje MeSH
• Trematoda růst a vývoj   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Španělsko MeSH

B lymfocyty jsou buňky imunitního systému zodpovědné především za specifickou, protilátkami zprostředkovanou imunitní odpověď. Odhaduje se, že lidský organizmus disponuje 1011 protilátkami s různou specifitou. V genomu neexistují specifické geny pro jednotlivé protilátky. Rozpor mezi obrovskou diverzitou protilátek a omezenou kódující kapacitou genomu je vyřešen kombinací unikátního uspořádání genetické informace pro imunoglobuliny a unikátními genetickými a somatickými procesy, které vytvoření tak širokého spektra různých protilátek zajistí. Tyto mechanizmy na jedné straně představují život ochraňující zdroj širokého spektra protilátek, na straně druhé představují život ohrožující riziko v podobě možnosti vývoje závažného nádorového onemocnění, B lymfomu. Lymfomy se dvěma zásahy tvoří mezi B lymfomy specifickou skupinu onemocnění. Nejčastěji nesou aberaci genů BCL2 a MYC. Důsledkem aktivace MYC, typické pro Burkittův lymfom (BL), je výrazná stimulace buněčného cyklu. Vysoká aktivita BCL2, typická pro folikulární lymfomy, způsobuje rezistenci k apoptóze. Paralelní závažné poškození regulace proliferace a apoptózy je příčinou charakteristických klinických projevů lymfomů se dvěma zásahy – velké agresivity, rezistence ke standardní terapii, vysokého rizika brzkého relapsu, krátkého celkového přežití, častého postižení extranodálních míst a centrální nervové soustavy. Lymfomy se dvěma zásahy v posledních letech přitahují velkou pozornost odborníků, mimo jiné proto, že přinášejí vhledy do procesu zrání lymfocytů a vývoje lymfomů a výrazně poukazují na dvousečnost mechanizmů umožňujících diverzifikaci protilátek. Případ: U 53letého muže byl na základě morfologických a imunofenotypických znaků dia­gnostikován B buněčný lymfom neklasifikovatelný, s rysy mezi difuzním velkobuněčným lymfomem (diffuse large B‑cell lymphoma – DLBCL) a BL. Cytogenetická analýza prokázala, že se jedná o lymfom se dvěma zásahy nesoucí translokaci t(14;18) a přestavbu MYC. Pacient zemřel pět měsíců po stanovení dia­gnózy.

B‑lymphocytes are cells of the immune system responsible for the antibody‑mediated immune response. As estimated, a human body can produce as much as 1011 specific antibodies. There are no specific genes coding for every individual antibody in the human genome. Discrepancy between the huge diversity of antibodies and limited coding capacity of the genome is solved by combination of unique arrangement of genetic information for immunoglobulin and unique genetic and somatic processes providing this wide spectrum of antibodies. On one side, these mechanisms represent a life protecting source of a wide spectrum of antibodies but at the same time, they can be life threatening by raising the risk of a serious tumor disease, the B‑cell lymphoma. Double‑hit lymphomas represent a specific group of B‑cell lymphomas often featuring concurrent rearrangements of BCL2 and MYC genes. Activation of the MYC oncogene, typical for Burkitt lymphoma (BL), causes strong stimulation of cell proliferation. High activity of BCL‑2, typical for follicular lymphoma, induces resistance to apoptosis. Concurrent damage of regulation of apoptosis and proliferation is probably responsible for the typical clinical manifestation of double‑hit lymphomas – aggressive course, resistance to conventional chemotherapy, high-risk of early relapse, short overall survival, frequent extranodal and central nervous system involvement. Recently, these lymphomas have attracted a strong attention of researchers as they provide sharp insights into processes of lymphocytes matur­ing and lymphomas development and highlight the double‑edged nature of mechanisms allowing the antibody broad diversity. Case report: Fifty‑three‑year‑old man was dia­gnosed with B‑cell lymphoma unclassifiable with features intermediate between diffuse large B‑cell lymphoma (DLBCL) and BL, based on morphology and immunophenotype. Fluorescent in situ hybridization analysis revealed double‑hit lymphoma dia­g­nosis as the tumor cells bear t(14;18) translocation concurrently with the MYC gene rearrangement. The patient died five months after dia­gnosis. Key words: B‑lymphocytes – antibody formation – B‑cell lymphoma – double‑hit lymphoma This study was supported by grant of Internal Grant Agency of the Czech ministry of Health No. NT/13519-4/2012. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE “uniform requirements” for biomedical papers. Submitted: 2. 8. 2013 Accepted: 11. 9. 2013

• MeSH
• amplifikace genu MeSH
• B-buněčný lymfom * diagnóza   genetika   patofyziologie   MeSH
• Burkittův lymfom MeSH
• chromozomální aberace MeSH
• genom lidský MeSH
• genová přestavba B-lymfocytů * MeSH
• hybridizace in situ fluorescenční MeSH
• imunofenotypizace MeSH
• lidé středního věku MeSH
• lidé MeSH
• molekulární biologie MeSH
• mutace genetika   MeSH
• příčina smrti MeSH
• proliferace buněk MeSH
• protoonkogenní proteiny c-bcl-2 genetika   MeSH
• protoonkogenní proteiny c-myc genetika   MeSH
• translokace genetická MeSH
• zárodečné centrum lymfatické uzliny patologie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• kazuistiky MeSH
• práce podpořená grantem MeSH
• přehledy MeSH