Lamprey is one of only two living jawless vertebrates, a group that includes the first vertebrates. Comparisons between lamprey and jawed vertebrates have yielded important insights into the origin ...and evolution of vertebrate physiology, morphology and development. Despite its key phylogenetic position, studies of lamprey have been limited by their complex life history, which makes traditional genetic approaches impossible. The CRISPR/Cas9 system is a bacterial defense mechanism that was recently adapted to achieve high-efficiency targeted mutagenesis in eukaryotes. Here we report CRISPR/Cas9-mediated disruption of the genes Tyrosinase and FGF8/17/18 in the sea lamprey Petromyzon marinus, and detail optimized parameters for producing mutant F0 embryos. Using phenotype and genotype analyses, we show that CRISPR/Cas9 is highly effective in the sea lamprey, with a majority of injected embryos developing into complete or partial mutants. The ability to create large numbers of mutant embryos without inbred lines opens exciting new possibilities for studying development in lamprey and other non-traditional model organisms with life histories that prohibit the generation of mutant lines.
•Electrochemical biosensor was used to detecting human papillomavirus (HPV) in real samples from endocervical swabs.•The detection limit was of 18.13nM.•No hybridization with non-complementary ...sequence showed that the method is selective.•It can be an excellent approach to detect human papillomavirus (HPV) in real samples.
An electrochemical DNA biosensor for human papillomavirus (HPV) 16 detection has been developed. For this proposed biosensor, l-cysteine was first electrodeposited on the gold electrode surface to form l-cysteine film (CYSFILM). Subsequently, HPV16-specific probe was immobilized on the electrode surface with CYSFILM. Electrochemistry measurement was studied by differential pulse voltammetry method (DPV). The measurement was based on the reduction signals of methylene blue (MB) before and after hybridization either between probe and synthetic target or extracted DNA from clinical samples. The effect of probe concentration was analyzed and the best results were seen at 1000nM. The hybridization detection presented high sensitivity and broad linear response to the synthetic-target concentration comprised between 18.75nM and 250nM as well as to a detection limit of 18.13nM. The performance of this biosensor was also investigated by checking probe-modified electrode hybridization with extracted DNA from samples. The results showed that the biosensor was successfully developed and exhibited high sensitivity and satisfactory selectivity to HPV16. These results allow for the possibility of developing a new portable detection system for HPVs and for providing help in making an effective diagnosis in the early stages of infection.
Under elevated atmospheric CO₂ concentrations, soil carbon (C) inputs are typically enhanced, suggesting larger soil C sequestration potential. However, soil C losses also increase and progressive ...nitrogen (N) limitation to plant growth may reduce the CO₂ effect on soil C inputs with time. We compiled a data set from 131 manipulation experiments, and used meta‐analysis to test the hypotheses that: (1) elevated atmospheric CO₂ stimulates soil C inputs more than C losses, resulting in increasing soil C stocks; and (2) that these responses are modulated by N. Our results confirm that elevated CO₂ induces a C allocation shift towards below‐ground biomass compartments. However, the increased soil C inputs were offset by increased heterotrophic respiration (Rh), such that soil C content was not affected by elevated CO₂. Soil N concentration strongly interacted with CO₂ fumigation: the effect of elevated CO₂ on fine root biomass and -production and on microbial activity increased with increasing soil N concentration, while the effect on soil C content decreased with increasing soil N concentration. These results suggest that both plant growth and microbial activity responses to elevated CO₂ are modulated by N availability, and that it is essential to account for soil N concentration in C cycling analyses.
Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport. A variety of mostly hereditary, structural or electrical cardiac disorders are associated with SCD in young ...athletes, the majority of which can be identified or suggested by abnormalities on a resting 12-lead electrocardiogram (ECG). Whether used for diagnostic or screening purposes, physicians responsible for the cardiovascular care of athletes should be knowledgeable and competent in ECG interpretation in athletes. However, in most countries a shortage of physician expertise limits wider application of the ECG in the care of the athlete. A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from distinctly abnormal findings suggestive of underlying pathology. Since the original 2010 European Society of Cardiology recommendations for ECG interpretation in athletes, ECG standards have evolved quickly, advanced by a growing body of scientific data and investigations that both examine proposed criteria sets and establish new evidence to guide refinements. On 26-27 February 2015, an international group of experts in sports cardiology, inherited cardiac disease, and sports medicine convened in Seattle, Washington (USA), to update contemporary standards for ECG interpretation in athletes. The objective of the meeting was to define and revise ECG interpretation standards based on new and emerging research and to develop a clear guide to the proper evaluation of ECG abnormalities in athletes. This statement represents an international consensus for ECG interpretation in athletes and provides expert opinion-based recommendations linking specific ECG abnormalities and the secondary evaluation for conditions associated with SCD.
A new electrochemical DNA biosensor for bovine papillomavirus (BPV) detection that was based on screen-printed electrodes was comprehensively studied by electrochemical methods of cyclic voltammetry ...(CV) and differential pulse voltammetry (DPV). A BPV probe was immobilised on a working electrode (gold) modified with a polymeric film of poly-L-lysine (PLL) and chitosan. The experimental design was carried out to evaluate the influence of polymers, probe concentration (BPV probe) and immobilisation time on the electrochemical reduction of methylene blue (MB). The polymer poly-L-lysine (PLL), a probe concentration of 1μM and an immobilisation time of 60min showed the best result for the BPV probe immobilisation. With the hybridisation of a complementary target sequence (BPV target), the electrochemical signal decreased compared to a BPV probe immobilised on the modified PLL-gold electrode. Viral DNA that was extracted from cattle with papillomatosis also showed a decrease in the MB electrochemical reduction, which suggested that the decreased electrochemical signal corresponded to a bovine papillomavirus infection. The hybridisation specificity experiments further indicated that the biosensor could discriminate the complementary sequence from the non-complementary sequence. Thus, the results showed that the development of analytical devices, such as a biosensor, could assist in the rapid and efficient detection of bovine papillomavirus DNA and help in the prevention and treatment of papillomatosis in cattle.
► Electrochemical DNA sensor used to detect bovine papillomavirus. ► Polymeric film from poly-L-lysine (PLL) and chitosan was formed on gold electrode. ► Methylene blue (MB) electrochemical reduction decreased when the hybridisation occurred. ► The extracted Viral DNA from cattle with papillomatosis also decreased electrochemical signal. ► The detection limit was 4.35nM in the range from 5nM to 100nM.
We examined the principal differences in photosynthetic characteristics between sun and shade foliage and determined the relative importance of biochemical and stomatal limitations during ...photosynthetic induction. Temperate-zone broadleaf and conifer tree species, ranging widely in shade tolerance, were investigated from one locality in the Czech Republic. The study species included strongly shade-tolerant Abies alba Mill. and Tilia cordata Mill., less shade-tolerant Fagus sylvatica L. and Acer pseudoplatanus L. and sun-demanding Picea abies (L.) Karst.
In the fully activated photosynthetic state, sun foliage of all species had significantly higher maximum CO2 assimilation rates, maximum stomatal conductance and maximum rates of carboxylation than shade foliage. Compared with shade leaves, sun leaves had significantly higher nocturnal stomatal conductances. In all species, shade foliage tended to have higher induction states 60 s after leaf illumination than sun foliage. Sun and shade foliage did not differ in the rate of disappearance of the transient biochemical limitation during the induction phase. Longer time periods were required to reach 90% photosynthetic induction and 90% stomatal induction in sun foliage than in shade foliage of the less shade-tolerant F. sylvatica and A. pseudoplatanus and in sun-demanding P. abies; however, in sun foliage of the strongly shade-tolerant species T. cordata and A. alba, the time needed for photosynthetic induction was similar to, or less than, that for shade foliage. Shade but not sun needles of P. abies and A. alba had significantly slower induction kinetics than the broadleaf tree species. Among species, the sun-demanding P. abies exhibited the shortest stomatal induction times in both sun and shade leaves. Independently of shade tolerance ranking, the transient stomatal and total limitations that characterize photosynthetic induction were relieved significantly earlier in shade foliage than in sun foliage. Sun foliage generally exhibited a hyperbolic photosynthetic induction response, whereas a sigmoidal induction response was more frequent in shade foliage. The different relative proportions of transient biochemical and stomatal limitations during photosynthetic induction in sun and shade foliage indicate an essential role of stomata in photosynthetic limitation during induction, mainly in shade foliage, with a consequent influence on the shape of the photosynthetic induction curve.
BACKGROUND AND AIMS: Stem and branch respiration, important components of total forest ecosystem respiration, were measured on Norway spruce (Picea abies) trees from May to October in four ...consecutive years in order (1) to evaluate the influence of temperature on woody tissue CO₂ efflux with special focus on variation in Q₁₀ (change in respiration rate resulting from a 10 °C increase in temperature) within and between seasons, and (2) to quantify the contribution of above-ground woody tissue (stem and branch) respiration to the carbon balance of the forest ecosystem. METHODS: Stem and branch CO₂ efflux were measured, using an IRGA and a closed gas exchange system, 3-4 times per month on 22-year-old trees under natural conditions. Measurements of ecosystem CO₂ fluxes were also determined during the whole experiment by using the eddy covariance system. Stem and branch temperatures were monitored at 10-min intervals during the whole experiment. KEY RESULTS: The temperature of the woody tissue of stems and branches explained up to 68 % of their CO₂ efflux. The mean annual Q₁₀ values ranged from 2·20 to 2·32 for stems and from 2·03 to 2·25 for branches. The mean annual normalized respiration rate, R₁₀, for stems and branches ranged from 1·71 to 2·12 μmol CO₂ m⁻²s ⁻¹ and from 0·24 to 0·31 μmol CO₂ m⁻² s⁻¹, respectively. The annual contribution of stem and branch CO₂ efflux to total ecosystem respiration were, respectively, 8·9 and 8·1 % in 1999, 9·2 and 9·2 % in 2000, 7·6 and 8·6 % in 2001, and 8·6 and 7·9 % in 2002. Standard deviation for both components ranged from 3 to 8 % of the mean. CONCLUSIONS: Stem and branch CO₂ efflux varied diurnally and seasonally, and were related to the temperature of the woody tissue and to growth. The proportion of CO₂ efflux from stems and branches is a significant component of the total forest ecosystem respiration, approx. 8 % over the 4 years, and predictive models must take their contribution into account.
ABSTRACT
The effects of elevated atmospheric CO2 concentration on growth of forest tree species are difficult to predict because practical limitations restrict experiments to much shorter than the ...average life‐span of a tree. Long‐term, process‐based computer models must be used to extrapolate from shorter‐term experiments. A key problem is to ensure a strong flow of information between experiments and models. In this study, meta‐analysis techniques were used to summarize a suite of photosynthetic model parameters obtained from 15 field‐based elevated CO2 experiments on European forest tree species. The parameters studied are commonly used in modelling photosynthesis, and include observed light‐saturated photosynthetic rates (Amax), the potential electron transport rate (Jmax), the maximum Rubisco activity (Vcmax) and leaf nitrogen concentration on mass (Nm) and area (Na) bases. Across all experiments, light‐saturated photosynthesis was strongly stimulated by growth in elevated CO2. However, significant down‐regulation of photosynthesis was also observed; when measured at the same CO2 concentration, photosynthesis was reduced by 10–20%. The underlying biochemistry of photosynthesis was affected, as shown by a down‐regulation of the parameters Jmax and Vcmax of the order of 10%. This reduction in Jmax and Vcmax was linked to the effects of elevated CO2 on leaf nitrogen concentration. It was concluded that the current model is adequate to model photosynthesis in elevated CO2. Tables of model parameter values for different European forest species are given.
Reprogramming, or generation of induced pluripotent stem (iPS) cells (functionally similar to embryonic stem cells or ES cells) by the use of transcription factors (typically: Oct3/4, Sox2, c-Myc, ...Klf4) called “Yamanaka factors” (OSKM), has revolutionized regenerative medicine. However, factors used to induce stemness are also overexpressed in cancer. Both, ES cells and iPS cells cause teratoma formation when injected to tissues. This raises a safety concern for therapies based on iPS derivates. Transdifferentiation (lineage reprogramming, or -conversion), is a process in which one mature, specialized cell type changes into another without entering a pluripotent state. This process involves an ectopic expression of transcription factors and/or other stimuli. Unlike in the case of reprogramming, tissues obtained by this method do not carry the risk of subsequent teratomagenesis.
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•Emergence of transdifferentiation as faster and potentially safer method of tissue conversion•Novel markers for delineation cancer stem cells and induced-pluripotent stem cells•Safer, reliable, more efficient and more clinically-compatible reprogramming methods relying on Sendai-virus based vectors•Importance of small molecules and epigenetic factors during reprogramming and transdifferentiation•Fast and reliable computational models for prediction of optimal sets of factors needed for transdifferentiation
We tested the hypothesis that leaf age affects photosynthetic induction, because conductance to CO2 diffusion usually decreases with increasing leaf age. Photosynthetic inductions, primarily ...determined by the light modulation of Rubisco activity and stomatal opening, were investigated in both young and mature leaves, as defined by leaf plastochron index (LPI), from three poplar clones: Populus alba L., P. nigra L. and P. x euramericana (Dode) Guinier. In all clones, maximum assimilation rates (Amax), maximum stomatal conductance (GSmax) and dark respiration rates (RD) were higher in young leaves (LPI = 3-5) than in mature leaves (LPI = 10-14), and Amax decreased from P. alba via P. x euramericana to P. nigra. The clones with high photosynthetic capacity had low induction states 60 s after leaf illumination (IS60; indicating a slow initial induction phase), and required less time to reach 90% photosynthetic induction (T90). In contrast, the clone with the lowest photosynthetic capacity (P. nigra) exhibited high IS60 (high initial induction state) but a long induction time (high T90). A comparison of mature leaves with young leaves revealed significantly (P < 0.01) lower IS60 values in mature leaves of P. nigra only, and significantly higher T90 values in mature leaves of P. alba only. In all clones, young leaves exhibited a lower percentage of maximum transient stomatal limitation during photosynthetic induction (4-9%) compared with mature leaves (16-30%). Transient biochemical limitation, assessed on the basis of the time constants of Rubisco activation (τ), was significantly higher in mature leaves than in young leaves of P. alba; whereas there were no significant differences in τ between young and mature leaves of the other poplar clones. Thus, our hypothesis that leaf age affects photosynthetic induction was confirmed at the level of transient stomatal limitation, which was significantly higher in mature leaves than in young leaves in all clones. For the induction parameters IS60, T90 and τ, photosynthetic induction was more clone-specific and was dependent on leaf age only in some cases, an observation that may apply to other tree species.
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