Bacterioplankton groups involved in the uptake of phosphate and dissolved organic phosphorus in a mesocosm experiment with P-starved Mediterranean waters

The use of inorganic phosphate (Pi) and dissolved organic phosphorus (DOP) by different bacterial groups was studied in experimental mesocosms of P-starved eastern Mediterranean waters in the absence (control mesocosms) and presence of additional Pi (P-amended mesocosms). The low Pi turnover times in the control mesocosms and the increase in heterotrophic prokaryotic abundance and production upon Pi addition confirmed that the bacterial community was originally P-limited. The bacterioplankton groups taking up Pi and DOP were identified by means of microautoradiography combined with catalysed reporter deposition fluorescence in situ hybridization. Incubations with leucine were also performed for comparative purposes. All the probe-identified groups showed a high percentage of cells taking up Pi and DOP in the control, P-limited, mesocosms throughout the experiment. However, in response to Pi addition two contrasting scenarios in Pi use were observed: (i) on day 1 of the experiment Pi addition caused a clear reduction in the percentage of SAR11 cells taking up Pi, whereas Gammaproteobacteria, Roseobacter and Bacteroidetes showed similar percentages to the ones in the control mesocosms and (ii) on day 4 of the experiment, probably when the bacterial community had fully responded to the P input, all the probe-identified groups showed low percentages of cells taking up the substrate as compared with the control mesocosms. These differences are likely related to different P requirements among the bacterial groups and point out to the existence of two contrasting strategies in P use.     

The Mediterranean Sea under siege: spatial overlap between marine biodiversity,cumulative threats and marine reserves

Aim A large body of knowledge exists on individual anthropogenic threats that have an impact on marine biodiversity in the Mediterranean Sea, although we know little about how these threats accumulate and interact to affect marine species and ecosystems. In this context, we aimed to identify the main areas where the interaction between marine biodiversity and threats is more pronounced and to assess their spatial overlap with current marine protected areas in the Mediterranean. Location Mediterranean Sea. Methods We first identified areas of high biodiversity of marine mammals, marine turtles, seabirds, fishes and commercial or well‐documented invertebrates. We mapped potential areas of high threat where multiple threats are occurring simultaneously. Finally we quantified the areas of conservation concern for biodiversity by looking at the spatial overlap between high biodiversity and high cumulative threats, and we assessed the overlap with protected areas. Results Our results show that areas with high marine biodiversity in the Mediterranean Sea are mainly located along the central and north shores, with lower values in the south‐eastern regions. Areas of potential high cumulative threats are widespread in both the western and eastern basins, with fewer areas located in the south‐eastern region. The interaction between areas of high biodiversity and threats for invertebrates, fishes and large animals in general (including large fishes, marine mammals, marine turtles and seabirds) is concentrated in the coastal areas of Spain, Gulf of Lions, north‐eastern Ligurian Sea, Adriatic Sea, Aegean Sea, south‐eastern Turkey and regions surrounding the Nile Delta and north‐west African coasts. Areas of concern are larger for marine mammal and seabird species. Main conclusions These areas may represent good candidates for further research, management and protection activities, since there is only a maximum 2% overlap between existing marine protected areas (which cover 5% of the Mediterranean Sea) and our predicted areas of conservation concern for biodiversity.     

Induction,rapid fixation and retention of mutations in vegetatively propagated banana

Mutation discovery technologies have enabled the development of reverse genetics for many plant species and allowed sophisticated evaluation of the consequences of mutagenesis. Such methods are relatively straightforward for seed‐propagated plants. To develop a platform suitable for vegetatively propagated species, we treated isolated banana shoot apical meristems with the chemical mutagen ethyl methanesulphonate, recovered plantlets and screened for induced mutations. A high density of GC‐AT transition mutations were recovered, similar to that reported in seed‐propagated polyploids. Through analysis of the inheritance of mutations, we observed that genotypically heterogeneous stem cells resulting from mutagenic treatment are rapidly sorted to fix a single genotype in the meristem. Further, mutant genotypes are stably inherited in subsequent generations. Evaluation of natural nucleotide variation showed the accumulation of potentially deleterious heterozygous alleles, suggesting that mutation induction may uncover recessive traits. This work therefore provides genotypic insights into the fate of totipotent cells after mutagenesis and suggests rapid approaches for mutation‐based functional genomics and improvement of vegetatively propagated crops.     

Early diagnostic markers of sepsis after oesophagectomy (including thromboelastography)

Background

Early diagnosis of sepsis and its differentiation from the noninfective SIRS is very important in order that treatment can be initiated in a timely and appropriate way. In this study we investigated standard haematological and biochemical parameters and thromboelastography (TEG) in patients who had undergone surgical resection of the oesophagus to find out if changes in any of these parameters could help in early differentiation between SIRS and sepsis development.

Methods

We enrolled 43 patients (aged 41?C74?years) of whom 38 were evaluable. Blood samples were obtained on the morning of surgery and then at 24-hour intervals for the next 6?days. Samples were analysed for procalcitonin (PCT), C-reactive protein (CRP), interleukin-6 (IL- 6), aspartate transaminase (AST), alanine transaminase (ALT) , lactate, white blood count (WBC), D-dimers, antithrombin (AT), international normalised ratio (INR), activated partial thromboplastin time (APTT) and parameters of TEG.

Results

Significant differences between patients who developed sepsis during this period (9 patients) and SIRS were found in ALT on Day 1, in AST on Days 1?C4, in PCT on Days 2?C6; in CRP on Days 3?C6; in IL-6 on Days 2?C5; in leucocytes on Days 2, 3 and 6; and in D-dimers on Days 2 and 4. Significance values ranged from p?Conclusions Sequential measurements of ALT, AST, PCT and IL-6 during the early postoperative period can be used for early differentiation of sepsis and postoperative SIRS after oesophagectomy. Among the coagulation parameters measured, only D-dimer concentrations appeared to be helpful in this process. TEG does not seem to be a useful early predictor of sepsis development; however it can be used to differentiate sepsis and SIRS from Day 5 after surgery.     

Cyclin-dependent kinases 4 and 6 control tumor progression and direct glucose oxidation in the pentose cycle

Cyclin-dependent kinases CDK4 and CDK6 are essential for the control of the cell cycle through the G(1) phase. Aberrant expression of CDK4 and CDK6 is a hallmark of cancer, which would suggest that CDK4 and CDK6 are attractive targets for cancer therapy. Herein, we report that calcein AM (the calcein acetoxymethyl-ester) is a potent specific inhibitor of CDK4 and CDK6 in HCT116 human colon adenocarcinoma cells, inhibiting retinoblastoma protein (pRb) phosphorylation and inducing cell cycle arrest in the G(1) phase. The metabolic effects of calcein AM on HCT116 cells were also evaluated and the flux between the oxidative and non-oxidative branches of the pentose phosphate pathway was significantly altered. To elucidate whether these metabolic changes were due to the inhibition of CDK4 and CDK6, we also characterized the metabolic profile of a CDK4, CDK6 and CDK2 triple knockout of mouse embryonic fibroblasts. The results show that the metabolic profile associated with the depletion of CDK4, CDK6 and CDK2 coincides with the metabolic changes induced by calcein AM on HCT116 cells, thus confirming that the inhibition of CDK4 and CDK6 disrupts the balance between the oxidative and non-oxidative branches of the pentose phosphate pathway. Taken together, these results indicate that low doses of calcein can halt cell division and kill tumor cells. Thus, selective inhibition of CDK4 and CDK6 may be of greater pharmacological interest, since inhibitors of these kinases affect both cell cycle progression and the robust metabolic profile of tumors.     

Synthesis of a natural chalcone and its prenyl analogs--evaluation of tumor cell growth-inhibitory activities, and effects on cell cycle and apoptosis

Six prenyl (=3-methylbut-2-en-1-yl) chalcones (=1,3-diphenylprop-2-en-1-ones), 2-7, and one natural non-prenylated chalcone, 1, have been synthesized and evaluated for their in vitro growth-inhibitory activity against three human tumor cell lines. A pronounced dose-dependent growth-inhibitory effect was observed for all prenylated derivatives, except for 7. The chalcone possessing one prenyloxy group at C(2'), i.e., 2, was the most active derivative against the three human tumor cell lines (5.9相似文献   

Autonomic Shutdown of Lithium‐Ion Batteries Using Thermoresponsive Microspheres

Autonomic, thermally‐induced shutdown of Lithium‐ion (Li‐ion) batteries is demonstrated by incorporating thermoresponsive polymer microspheres (ca. 4 μm) onto battery anodes or separators. When the internal battery environment reaches a critical temperature, the microspheres melt and coat the anode/separator with a nonconductive barrier, halting Li‐ion transport and shutting down the cell permanently. Three functionalization schemes are shown to perform cell shutdown: 1) poly(ethylene) (PE) microspheres coated on the anode, 2) paraffin wax microspheres coated on the anode, and 3) PE microspheres coated on the separator. Charge and discharge capacity is measured for Li‐ion coin cells containing microsphere‐coated anodes or separators as a function of capsule coverage. For PE coated on the anode, the initial capacity of the battery is unaffected by the presence of the PE microspheres up to a coverage of 12 mg cm^?2 (when cycled at 1C), and full shutdown (>98% loss of initial capacity) is achieved in cells containing greater than 3.5 mg cm^?2. For paraffin microspheres coated on the anode and PE microspheres coated on the separator, shutdown is achieved in cells containing coverages greater than 2.9 and 13.7 mg cm^?2, respectively. Scanning electron microscopy images of electrode surfaces from cells that have undergone autonomic shutdown provides evidence of melting, wetting, and resolidification of PE into the anode and polymer film formation at the anode/separator interface.     

Use of a new violet-excitable AmCyan variant as a label in cell analysis

Here we report a new variant of AmCyan fluorescent protein that has been specifically designed for multicolor cell analysis. AmCyan is one of the existing violet fluorochromes for use in flow cytometers equipped with a violet (405 nm) laser. It is also widely used as a label in fluorescent spectroscopy. Limitations on its use are due to the significant AmCyan fluorescence spillover into the FITC detector, due to excitation of AmCyan by the blue (488 nm) laser. In order to resolve this problem, we modified the excitation profile of AmCyan. The new fluorescent protein that we developed, AmCyan100, has an emission profile similar to AmCyan with an emission maximum at 500 nm, but its excitation maximum is shifted to 395 nm, which coincides more closely with the violet laser line and decreases the excitation with the blue laser, thus reducing the spillover observed with the original AmCyan. Moreover, this new protein has a Stokes shift of more than 100 nm compared to the Stokes shift of 31 nm in its precursor. Our data also suggests that AmCyan100-mAb conjugates have brightness similar to AmCyan-mAb conjugates. In summary, AmCyan100 conjugates have minimum spillover into the FITC detector, and can potentially replace existing AmCyan conjugates in multicolor flow cytometry without any changes in instrumental setup and existing reagent panel design.