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51.
Eeshita G. Dastidar Kristina Dzeyk Jeroen Krijgsveld Nicholas A. Malmquist Christian Doerig Artur Scherf Jose-Juan Lopez-Rubio 《PloS one》2013,8(1)
The important role of histone posttranslational modifications, particularly methylation and acetylation, in Plasmodium falciparum gene regulation has been established. However, the role of histone phosphorylation remains understudied. Here, we investigate histone phosphorylation utilizing liquid chromatography and tandem mass spectrometry to analyze histones extracted from asexual blood stages using two improved protocols to enhance preservation of PTMs. Enrichment for phosphopeptides lead to the detection of 14 histone phospho-modifications in P. falciparum. The majority of phosphorylation sites were observed at the N-terminal regions of various histones and were frequently observed adjacent to acetylated lysines. We also report the identification of one novel member of the P. falciparum histone phosphosite binding protein repertoire, Pf14-3-3I. Recombinant Pf14-3-3I protein bound to purified parasite histones. In silico structural analysis of Pf14-3-3 proteins revealed that residues responsible for binding to histone H3 S10ph and/or S28ph are conserved at the primary and the tertiary structure levels. Using a battery of H3 specific phosphopeptides, we demonstrate that Pf14-3-3I preferentially binds to H3S28ph over H3S10ph, independent of modification of neighbouring residues like H3S10phK14ac and H3S28phS32ph. Our data provide key insight into histone phosphorylation sites. The identification of a second member of the histone modification reading machinery suggests a widespread use of histone phosphorylation in the control of various nuclear processes in malaria parasites. 相似文献
52.
Carlo L. Seifert Greg P. A. Lamarre Martin Volf Leonardo R. Jorge Scott E. Miller David L. Wagner Kristina J. Anderson-Teixeira Vojtch Novotn 《Oecologia》2020,192(2):501-514
Vertical niche partitioning might be one of the main driving forces explaining the high diversity of forest ecosystems. However, the forest’s vertical dimension has received limited investigation, especially in temperate forests. Thus, our knowledge about how communities are vertically structured remains limited for temperate forest ecosystems. In this study, we investigated the vertical structuring of an arboreal caterpillar community in a temperate deciduous forest of eastern North America. Within a 0.2-ha forest stand, all deciduous trees ≥ 5 cm diameter at breast height (DBH) were felled and systematically searched for caterpillars. Sampled caterpillars were assigned to a specific stratum (i.e. understory, midstory, or canopy) depending on their vertical position and classified into feeding guild as either exposed feeders or shelter builders (i.e. leaf rollers, leaf tiers, webbers). In total, 3892 caterpillars representing 215 species of butterflies and moths were collected and identified. While stratum had no effect on caterpillar density, feeding guild composition changed significantly with shelter-building caterpillars becoming the dominant guild in the canopy. Species richness and diversity were found to be highest in the understory and midstory and declined strongly in the canopy. Family and species composition changed significantly among the strata; understory and canopy showed the lowest similarity. Food web analyses further revealed an increasing network specialization towards the canopy, caused by an increase in specialization of the caterpillar community. In summary, our study revealed a pronounced stratification of a temperate forest caterpillar community, unveiling a distinctly different assemblage of caterpillars dwelling in the canopy stratum. 相似文献
53.
Nickolay V. Bukoreshtliev Kristina Haase Andrew E. Pelling 《Cell and tissue research》2013,352(1):77-94
Multicellular organisms comprise an organized array of individual cells surrounded by a meshwork of biomolecules and fluids. Cells have evolved various ways to communicate with each other, so that they can exchange information and thus fulfil their specified and unique functions. At the same time, cells are also physical entities that are subjected to a variety of local and global mechanical cues arising in the microenvironment. Cells are equipped with several different mechanisms to sense the physical properties of the microenvironment and the mechanical forces arising within it. These mechanical cues can elicit a variety of responses that have been shown to play a crucial role in vivo. In this review, we discuss the current views and understanding of cell mechanics and demonstrate the emerging evidence of the interplay between physiological mechanical cues and cell-cell communication pathways. 相似文献
54.
Eva Hell Christian G. Giske Kjell Hultenby Kristina Gemzell Danielsson Giovanna Marchini 《Current microbiology》2013,67(6):712-717
Staphylococcus epidermidis, a human commensal, is an important opportunistic, biofilm-forming pathogen and the main cause of late onset sepsis in preterm infants, worldwide. In this study we describe the characteristics of S. epidermidis strains causing late onset (>72 h) bloodstream infection in preterm infants and skin isolates from healthy newborns. Attachment and biofilm formation capability were analyzed in microtiter plates and with transmission electron microscopy (TEM). Clonal relationship among strains was studied with pulsed-field gel electrophoresis. Antimicrobial susceptibility testing was performed, as well as the detection of biofilm-associated genes and of the invasiveness marker IS256 with polymerase chain reaction. Blood and skin isolates had similar attachment and biofilm-forming capabilities and biofilm formation was not related to the presence of specific genes. Filament-like membrane structures were seen by TEM early in the attachment close to the device surface, both in blood and skin strains. Nine of the ten blood isolates contained the IS256 and were also resistant to methicillin and gentamicin in contrast to skin strains. S. epidermidis strains causing bloodstream infection in preterm infants exhibit higher antibiotic resistance and are provided with an invasive genetic equipment compared to skin commensal strains. Adhesion capability to a device surface seems to involve bacterial membrane filaments. 相似文献
55.
Xuan Pan Madhusudhan Papasani Yi Hao Marco Calamito Fang Wei William J Quinn Arindam Basu Junwen Wang Suchita Hodawadekar Kristina Zaprazna Huifei Liu Yang Shi David Allman Michael Cancro Michael L Atchison 《The EMBO journal》2013,32(8):1168-1182
Conditional knock‐out (KO) of Polycomb Group (PcG) protein YY1 results in pro‐B cell arrest and reduced immunoglobulin locus contraction needed for distal variable gene rearrangement. The mechanisms that control these crucial functions are unknown. We deleted the 25 amino‐acid YY1 REPO domain necessary for YY1 PcG function, and used this mutant (YY1ΔREPO), to transduce bone marrow from YY1 conditional KO mice. While wild‐type YY1 rescued B‐cell development, YY1ΔREPO failed to rescue the B‐cell lineage yielding reduced numbers of B lineage cells. Although the IgH rearrangement pattern was normal, there was a selective impact at the Igκ locus that showed a dramatic skewing of the expressed Igκ repertoire. We found that the REPO domain interacts with proteins from the condensin and cohesin complexes, and that YY1, EZH2 and condensin proteins co‐localize at numerous sites across the Ig kappa locus. Knock‐down of a condensin subunit protein or YY1 reduced rearrangement of Igκ Vκ genes suggesting a direct role for YY1‐condensin complexes in Igκ locus structure and rearrangement. 相似文献
56.
Kristina Zakharova Donatella Tesei Gorji Marzban Jan Dijksterhuis Timon Wyatt Katja Sterflinger 《Mycopathologia》2013,175(5-6):537-547
Black microcolonial fungi (MCF) and black yeasts are among the most stress-resistant eukaryotic organisms known on Earth. They mainly inhabit bare rock surfaces in hot and cold deserts of all regions of the Earth, but some of them have a close phylogenetic relation to human pathogenic black fungi which makes them important model organisms also with respect to clinical mycology. The environment of those fungi is especially characterized by extreme changes from humidity to long periods of desiccation and extreme temperature differences. A key to the understanding of MCF ecology is the question about metabolic activity versus dormancy in the natural environments. In this study, the time lag from the desiccated state to rehydration and full metabolic activity and growth was measured and defined in accordance with simulated environmental conditions. The ability to survive after desiccation and the speed of rehydration as well as changes of the whole cell protein pattern are demonstrated. Whereas both mesophilic strains—Exophiala jeanselmei and Knufia perforans (=Coniosporium perforans)—show a clear reaction toward desiccation by production of small proteins, Cryomyces antarcticus—the extremotolerant MCF—does not show any response to desiccation but seems just to down-regulate its metabolism. Data on intracellular sugar suggest that both trehalose and mannitol might play a cell protective role in those fungi. 相似文献
57.
Kristina Hasakova Marian Vician Richard Reis Michal Zeman 《Chronobiology international》2013,30(10):1423-1434
ABSTRACTRecent evidence supports the important role of the circadian system in cancer progression in humans. The aim of the present study is to evaluate clock (cry1, cry2 and per2) and clock-controlled (vascular endothelial growth factor-a, early growth response protein 1 and estrogen receptor β) gene expression in colorectal cancer and adjacent tissue and identify a possible link between survival of patients and expression of above mentioned genes. The study includes 64 patients of both sexes with previously diagnosed colorectal cancer. RNA was extracted from the tumor tissue and adjacent parts of the resected colon, and real-time PCR was used for detection of clock gene expression. Expression of cry2 and per2 was significantly downregulated in tumor tissue compared to adjacent tissues. After splitting of the cohort according to sex, we detected downregulated levels of cry2 and per2 in male patients, but not in females. Splitting of male and female sub-cohorts according to presence of metastases revealed significant donwregulation of cry2 expression in female patients without distant metastasis. Better survival rate was associated with low expression of cry2 in female patients. Moreover, we observed an increase in cry1 expression in female patients with distant metastases in tumor compared to adjacent tissue. Accordingly, women with high expression of cry1 in tumor tissue displayed worse survival, which was not observed in men. Taken together, expression of clock and clock-controlled genes in tumors of males and females clustered according to presence of distant metastases correlated with survival analysis. Studied clock-controlled genes also showed sex-dependent changes. Low expression of vegf-a in tumor correlated with better survival in men but not in women. High expression of estrogen receptor β mRNA was related to better survival in women but not in men. Low expression of vegf-a, egr1 and estrogen receptor β was associated with worse survival in women compared to men. Our data indicate sex-dependent associations between clock and clock-controlled gene expression in cancer tissue and patient’s survival prognosis. 相似文献
58.
Dilfuza Egamberdieva Gabriela Berg Kristina Lindström Leena A. Räsänen 《Plant and Soil》2013,369(1-2):453-465
Background and aims
Salt stress is an increasing problem in agricultural soils in many parts of the world, and salt tolerant cropping systems are in great demand. We investigated the effect of co-inoculation of Galega officinalis with Rhizobium galegae and two plant growth promoting Pseudomonas species on plant growth, nodulation, and N content under salt stress.Methods
The effect of inoculation with R. galegae sv. officinalis HAMBI 1141 alone and in combination with the root-colonizing Pseudomonas extremorientalis TSAU20 or Pseudomonas trivialis 3Re27 on the growth of G. officinalis exposed to salt stress (50 and 75 mM NaCl) was studied under gnotobiotic and greenhouse conditions.Results
The growth of goat’s rue was reduced at 50 and 75 mM NaCl both in the gnotobiotic sand system and in low-fertilized potting soil in the greenhouse. Co-inoculation of unstressed and salt-stressed goat’s rue with R. galegae HAMBI 1141 and either P. extremorientalis TSAU20 or P. trivialis 3Re27 significantly improved root and shoot growth and increased nodulation of plant roots in both growth systems compared with plants inoculated with R. galegae alone. The nitrogen content of co-inoculated plant roots was significantly increased at 75 mM NaCl in potting soil. Co-inoculation of G. officinalis with either of the two plant growth promoting (PGPR) Pseudomonas strains also improved root tip-colonization by R. galegae cells.Conclusions
The co-inoculation of goat’s rue with Rhizobium and PGPR Pseudomonas strains alleviated salt stress of plants grown in NaCl-amended gnotobiotic sand systems and in potting soil in the greenhouse. 相似文献59.
Waterborne chemical cues are an important source of information for many aquatic organisms, in particular when assessing the current risk of predation. The ability to use chemical cues to detect and respond to potential predators before an actual encounter can improve prey chances of survival. We investigated predator recognition and the impact of chemical cues on predator avoidance in the freshwater isopod Asellus aquaticus. This isopod has recently colonised a novel habitat and diverged into two distinct ecotypes, which encounter different predator communities. Using laboratory-based choice experiments, we have quantified behavioural responses to chemical cues from predators typical of the two predator communities (larval dragonflies in the ancestral habitat, perch in the newly colonised habitat) in wild-caught and lab-reared Asellus of the two ecotypes. Individuals with prior experience of predators showed strong predator avoidance to cues from both predator types. Both ecotypes showed similar antipredator responses, but sexes differed in terms of threat-sensitive responses with males avoiding areas containing predator cues to a larger extent than females. Overall, chemical cues from fish elicited stronger predator avoidance than cues from larval dragonflies. Our results indicate that in these isopods, prior exposure to predators is needed to develop antipredator behaviour based on waterborne cues. Furthermore, the results emphasise the need to analyse predator avoidance in relation to waterborne cues in a sex-specific context, because of potential differences between males and females in terms of vulnerability and life history strategies. 相似文献
60.
Chandni Praveen Brooke A. Dancho David H. Kingsley Kevin R. Calci Gloria K. Meade Kristina D. Mena Suresh D. Pillai 《Applied and environmental microbiology》2013,79(12):3796-3801
Consumption of raw oysters is an exposure route for human norovirus (NoV) and hepatitis A virus (HAV). Therefore, efficient postharvest oyster treatment technology is needed to reduce public health risks. This study evaluated the inactivation of HAV and the NoV research surrogate, murine norovirus-1 (MNV-1), in oysters (Crassostrea virginica) by electron beam (E-beam) irradiation. The reduction of potential infection risks was quantified for E-beam irradiation technology employed on raw oysters at various virus contamination levels. The E-beam dose required to reduce the MNV and HAV titer by 90% (D10 value) in whole oysters was 4.05 (standard deviations [SD], ±0.63) and 4.83 (SD, ±0.08) kGy, respectively. Microbial risk assessment suggests that if a typical serving of 12 raw oysters was contaminated with 105 PFU, a 5-kGy treatment would achieve a 12% reduction (from 4.49 out of 10 persons to 3.95 out of 10 persons) in NoV infection and a 16% reduction (from 9.21 out of 10 persons to 7.76 out of 10 persons) in HAV infections. If the serving size contained only 102 PFU of viruses, a 5-kGy treatment would achieve a 26% reduction (2.74 out of 10 persons to 2.03 out of 10 persons) of NoV and 91% reduction (2.1 out of 10 persons to 1.93 out of 100 persons) of HAV infection risks. This study shows that although E-beam processing cannot completely eliminate the risk of viral illness, infection risks can be reduced. 相似文献