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951.
Phytoplankton succession and sinking rates were studied from January to December 2003 at a coastal station in the Gulf of
Trieste (northern Adriatic Sea), 200 m offshore, in a relatively undisturbed area. A conical sediment trap, moored at 15 m
depth (water depth 17 m), was used. The hypothesis if the presence of benthic and epiphytic diatoms can lead to an overestimation
of the vertical fluxes was tested. To evaluate primary and secondary sedimentation contributions, planktonic, benthic and
epiphytic diatoms were distinguished. Benthic species abundance varied throughout the year and it was related to resuspension
that strongly influenced sinking rates. All over the year, diatoms were the prevailing class in the trap material accounting
for 75.32% of the settled cells, while flagellates represented 24.11%. Dinophyceae and resting cells constituted minor components,
accounting for 0.43% and 0.14%, respectively. The gross sedimentation rates ranged from 0.006 × 108 cell m−2 d−1 in the second week of May to 6.30 × 108 cell m−2 d−1 in the third week of January with a mean annual value of 1.09 ± 1.43 × 108 cell m−2 d−1. To the primary sedimentation rate Pseudo-nitzschia seriata of the group “Nitzschia seriata complex” contributed for 49.77% followed by Chaetoceros spp. (23.88%). The major contributor to the secondary sedimentation rate was the diatom Paralia sulcata, accounting for 24.76%. Epiphytic diatoms contributed for 11.19% and 12.27% on annual average gross abundance and biomass,
respectively, reaching even 72.04% of gross abundance and 56.06% of gross biomass in the second week of August. The correlation
between temperature and the logarithm of the epiphytic biomass was statistically significant, with r = 0.66 and P < 0.001. Both in the cluster analysis and in the PCA four main groups were formed, where benthic and epiphytic species were
separately gathered. Planktonic, benthic and epiphytic forms accounted for 50.78%, 36.95% and 12.27%, respectively, calculated
on the annual average biomass. Therefore, vertical fluxes can be overestimated of 50% or more if benthic and epiphytic species
are not rejected. 相似文献
952.
Ronda L Faggiano S Bettati S Hellmann N Decker H Weidenbach T Mozzarelli A 《Gene》2007,398(1-2):202-207
Cooperativity depends on the existence of equilibria among functionally distinct conformational states that are affected by homo and heterotropic effectors. In order to isolate the quaternary conformations of hemocyanin from E. californicum, the 24-meric giant protein was encapsulated in wet, nanoporous silica gels, either in the absence or presence of oxygen. The deoxy- and oxy-hemocyanin gels exhibit a p50 for oxygen of 11 and 2.5 torr, respectively, values in close agreement with those for hemocyanin in solution. The observed Hill coefficients are lower than unity, indicating a conformational heterogeneity within each locked conformational state, a finding in agreement with the assumption that at least four conformational states are required to explain the oxygen binding properties of E. californicum hemocyanin in solution. 相似文献
953.
Identification of a Moraxella catarrhalis gene that confers adherence to various human epithelial cell lines in vitro 总被引:1,自引:0,他引:1
Moraxella catarrhalis is a pathogen of the human airways. We found that expression of the M. catarrhalis gene mcmA by Escherichia coli increases adherence to epithelial cells 100-fold. Furthermore, we discovered that disrupting mcmA decreases M. catarrhalis adherence to laryngeal and lung cells, which are relevant to pathogenesis by the bacterium. 相似文献
954.
Mershon SM Anding AL Chapman JS Clagett-Dame M Stonerock LA Curley RW 《Bioorganic & medicinal chemistry letters》2007,17(3):836-840
Using solid phase-assisted synthesis and purification, a 49 member library of analogs of the mammary tumor chemopreventive retinoid N-(4-hydroxyphenyl)retinamide (4-HPR) has been prepared. After prescreening for growth inhibitory activity in human mammary tumor cells (MCF-7) in culture, most of those analogs which showed activity (12 of them) were assayed for apoptosis-inducing activity in the MCF-7 cells. At least 3 of the analogs (13, 24, and 28) showed activity approaching that of 4-HPR. 相似文献
955.
Lucrezia Zerillo Immacolata Polvere Romualdo Varricchio Jessica Raffaella Madera Silvia D’Andrea Serena Voccola Iacopo Franchini Romania Stilo Pasquale Vito Tiziana Zotti 《Microbial biotechnology》2022,15(5):1422-1433
The use of medical devices, such as contact lenses, represents a substantial risk of infection, as they can act as scaffolds for formation of microbial biofilms. Recently, the increasing emergency of antibiotic resistance has prompted the development of novel and effective antimicrobial drugs for biofilm treatment, such as oxidizing agents. The purpose of this study is to investigate the effects of Ozodrop® and Ozodrop® gel, commercial names of ozonated oil in liposomes plus hypromellose, on eradication and de novo formation of biofilms on different supports, such as plastic plates and contact lens. Our results demonstrate that ozonated liposomal sunflower oil plus hypromellose have an excellent inhibitory effect on bacterial viability and on both de novo formation and eradication of biofilms produced on plates and contact lens by Pseudomonas aeruginosa and Staphylococcus aureus. Moreover, we show that Ozodrop® formulations stimulate expression of antimicrobial peptides and that Ozodrop® gel has a strong repair activity on human epithelial cells, suggesting further applications for the treatment of non-healing infected wounds. 相似文献
956.
957.
Francesca Rizzo Kathryn M. Edenborough Roberto Toffoli Paola Culasso Simona Zoppi Alessandro Dondo Serena Robetto Sergio Rosati Angelika Lander Andreas Kurth Riccardo Orusa Luigi Bertolotti Maria Lucia Mandola 《BMC veterinary research》2017,13(1):396
Background
Bat-borne virus surveillance is necessary for determining inter-species transmission risks and is important due to the wide-range of bat species which may harbour potential pathogens. This study aimed to monitor coronaviruses (CoVs) and paramyxoviruses (PMVs) in bats roosting in northwest Italian regions. Our investigation was focused on CoVs and PMVs due to their proven ability to switch host and their zoonotic potential. Here we provide the phylogenetic characterization of the highly conserved polymerase gene fragments.Results
Family-wide PCR screenings were used to test 302 bats belonging to 19 different bat species. Thirty-eight animals from 12 locations were confirmed as PCR positive, with an overall detection rate of 12.6% [95% CI: 9.3–16.8]. CoV RNA was found in 36 bats belonging to eight species, while PMV RNA in three Pipistrellus spp. Phylogenetic characterization have been obtained for 15 alpha- CoVs, 5 beta-CoVs and three PMVs; moreover one P. pipistrellus resulted co-infected with both CoV and PMV. A divergent alpha-CoV clade from Myotis nattereri SpA is also described. The compact cluster of beta-CoVs from R. ferrumequinum roosts expands the current viral sequence database, specifically for this species in Europe. To our knowledge this is the first report of CoVs in Plecotus auritus and M. oxygnathus, and of PMVs in P. kuhlii.Conclusions
This study identified alpha and beta-CoVs in new bat species and in previously unsurveyed Italian regions. To our knowledge this represents the first and unique report of PMVs in Italy. The 23 new bat genetic sequences presented will expand the current molecular bat-borne virus databases. Considering the amount of novel bat-borne PMVs associated with the emergence of zoonotic infections in animals and humans in the last years, the definition of viral diversity within European bat species is needed. Performing surveillance studies within a specific geographic area can provide awareness of viral burden where bats roost in close proximity to spillover hosts, and form the basis for the appropriate control measures against potential threats for public health and optimal management of bats and their habitats.958.
959.
Maria Vougioukalaki Joris Demmers Wilbert P. Vermeij Marjolein Baar Serena Bruens Aristea Magaraki Ewart Kuijk Myrthe Jager Sarra Merzouk Renata M.C. Brandt Janneke Kouwenberg Ruben van Boxtel Edwin Cuppen Joris Pothof Jan H. J. Hoeijmakers 《Aging cell》2022,21(4)
Organs age differently, causing wide heterogeneity in multimorbidity, but underlying mechanisms are largely elusive. To investigate the basis of organ‐specific ageing, we utilized progeroid repair‐deficient Ercc1Δ /− mouse mutants and systematically compared at the tissue, stem cell and organoid level two organs representing ageing extremes. Ercc1Δ /− intestine shows hardly any accelerated ageing. Nevertheless, we found apoptosis and reduced numbers of intestinal stem cells (ISCs), but cell loss appears compensated by over‐proliferation. ISCs retain their organoid‐forming capacity, but organoids perform poorly in culture, compared with WT. Conversely, liver ages dramatically, even causing early death in Ercc1‐KO mice. Apoptosis, p21, polyploidization and proliferation of various (stem) cells were prominently elevated in Ercc1Δ /− liver and stem cell populations were either largely unaffected (Sox9+), or expanding (Lgr5+), but were functionally exhausted in organoid formation and development in vitro. Paradoxically, while intestine displays less ageing, repair in WT ISCs appears inferior to liver as shown by enhanced sensitivity to various DNA‐damaging agents, and lower lesion removal. Our findings reveal organ‐specific anti‐ageing strategies. Intestine, with short lifespan limiting time for damage accumulation and repair, favours apoptosis of damaged cells relying on ISC plasticity. Liver with low renewal rates depends more on repair pathways specifically protecting the transcribed compartment of the genome to promote sustained functionality and cell preservation. As shown before, the hematopoietic system with intermediate self‐renewal mainly invokes replication‐linked mechanisms, apoptosis and senescence. Hence, organs employ different genome maintenance strategies, explaining heterogeneity in organ ageing and the segmental nature of DNA‐repair‐deficient progerias. 相似文献
960.
Lecca D Trincavelli ML Gelosa P Sironi L Ciana P Fumagalli M Villa G Verderio C Grumelli C Guerrini U Tremoli E Rosa P Cuboni S Martini C Buffo A Cimino M Abbracchio MP 《PloS one》2008,3(10):e3579
Deciphering the mechanisms regulating the generation of new neurons and new oligodendrocytes, the myelinating cells of the central nervous system, is of paramount importance to address new strategies to replace endogenous damaged cells in the adult brain and foster repair in neurodegenerative diseases. Upon brain injury, the extracellular concentrations of nucleotides and cysteinyl-leukotrienes (cysLTs), two families of endogenous signaling molecules, are markedly increased at the site of damage, suggesting that they may act as "danger signals" to alert responses to tissue damage and start repair. Here we show that, in brain telencephalon, GPR17, a recently deorphanized receptor for both uracil nucleotides and cysLTs (e.g., UDP-glucose and LTD(4)), is normally present on neurons and on a subset of parenchymal quiescent oligodendrocyte precursor cells. We also show that induction of brain injury using an established focal ischemia model in the rodent induces profound spatiotemporal-dependent changes of GPR17. In the lesioned area, we observed an early and transient up-regulation of GPR17 in neurons expressing the cellular stress marker heat shock protein 70. Magnetic Resonance Imaging in living mice showed that the in vivo pharmacological or biotechnological knock down of GPR17 markedly prevents brain infarct evolution, suggesting GPR17 as a mediator of neuronal death at this early ischemic stage. At later times after ischemia, GPR17 immuno-labeling appeared on microglia/macrophages infiltrating the lesioned area to indicate that GPR17 may also acts as a player in the remodeling of brain circuitries by microglia. At this later stage, parenchymal GPR17+ oligodendrocyte progenitors started proliferating in the peri-injured area, suggesting initiation of remyelination. To confirm a specific role for GPR17 in oligodendrocyte differentiation, the in vitro exposure of cortical pre-oligodendrocytes to the GPR17 endogenous ligands UDP-glucose and LTD(4) promoted the expression of myelin basic protein, confirming progression toward mature oligodendrocytes. Thus, GPR17 may act as a "sensor" that is activated upon brain injury on several embryonically distinct cell types, and may play a key role in both inducing neuronal death inside the ischemic core and in orchestrating the local remodeling/repair response. Specifically, we suggest GPR17 as a novel target for therapeutic manipulation to foster repair of demyelinating wounds, the types of lesions that also occur in patients with multiple sclerosis. 相似文献