Characteristics of C-4 photosynthesis in stems and petioles of C-3 flowering plants

Most plants are known as C-3 plants because the first product of photosynthetic CO2 fixation is a three-carbon compound. C-4 plants, which use an alternative pathway in which the first product is a four-carbon compound, have evolved independently many times and are found in at least 18 families. In addition to differences in their biochemistry, photosynthetic organs of C-4 plants show alterations in their anatomy and ultrastructure. Little is known about whether the biochemical or anatomical characteristics of C-4 photosynthesis evolved first. Here we report that tobacco, a typical C-3 plant, shows characteristics of C-4 photosynthesis in cells of stems and petioles that surround the xylem and phloem, and that these cells are supplied with carbon for photosynthesis from the vascular system and not from stomata. These photosynthetic cells possess high activities of enzymes characteristic of C-4 photosynthesis, which allow the decarboxylation of four-carbon organic acids from the xylem and phloem, thus releasing CO2 for photosynthesis. These biochemical characteristics of C-4 photosynthesis in cells around the vascular bundles of stems of C-3 plants might explain why C-4 photosynthesis has evolved independently many times

High throughput method for analysis of repeat number for 28 phase variable loci of C. jejuni strain NCTC11168

Mutations in simple sequence repeat tracts are a major mechanism of phase variation in several bacterial species including Campylobacter jejuni. Changes in repeat number of tracts located within the reading frame can produce a high frequency of reversible switches in gene expression between ON and OFF states. The genome of C. jejuni strain NCTC11168 contains 29 loci with polyG/polyC tracts of seven or more repeats. This protocol outlines a method for rapidly determining ON/OFF states of these 28 phase-variable loci in a large number of individual colonies. The method combines a series of multiplex PCR assays with a GeneScan assay and automated extraction of tract length, repeat number and expression state. This high throughput, multiplex assay has utility for detecting shifts in phase variation states within and between populations over time and for exploring the effects of phase variation on adaptation to differing selective pressures. An important output of this assay is combinatorial expression states that cannot be determined by other methods. This method can be adapted to analysis of phase variation in other C. jejuni strains and in a diverse range of bacterial species

Optimizing a Retention Strategy with Young People for BRIGHTLIGHT, a Longitudinal Cohort Study Examining the Value of Specialist Cancer Care for Young People

PURPOSE: To maximize retention of participants in a longitudinal cohort study, we sought to understand young peoples' views about barriers and facilitators to continuing study participation. METHODS: Ten young people with a previous cancer diagnosis aged 15-24 participated in a 1 day workshop. The workshop used participatory methodology consisting of three exercises as follows: role play/scene setting; force field analysis of research participation in small groups; and focus group discussion. A final prioritization exercise was administered individually after the workshop. RESULTS: Twenty-four barriers to maintaining participation were summarized in five themes as follows: life commitments; concerns specific to the study; emotional barriers; practical barriers; and other reasons. The top 3 specific barriers were as follows: not a priority/other things are more important; too time consuming; and forgetting/memory. The top 3 facilitators for participation were as follows: wishing to help other young people; giving back to the cancer community; and honoring an initial commitment to participation. The top 3 suggested solutions to encourage continued participation were as follows: reminder text message or email before each survey to check preferred method of delivery; breaking up the online survey into modules to make completion less overwhelming; and consolidation of study information in one location. CONCLUSION: Involving young people in designing a retention strategy for young people with cancer has informed the BRIGHTLIGHT retention strategy. Patient and public involvement is imperative for successful research but measuring impact is challenging. The success of implementing the changes to optimize retention was shown in the increase in retention in Wave 3 from 30% to final participation of 58%

Effective Rheology of Bubbles Moving in a Capillary Tube

We calculate the average volumetric flux versus pressure drop of bubbles moving in a single capillary tube with varying diameter, finding a square-root relation from mapping the flow equations onto that of a driven overdamped pendulum. The calculation is based on a derivation of the equation of motion of a bubble train from considering the capillary forces and the entropy production associated with the viscous flow. We also calculate the configurational probability of the positions of the bubbles.Comment: 4 pages, 1 figur

Fresh-blood-free diet for rearing malaria mosquito vectors

Mosquito breeding depends on the supply of fresh vertebrate blood, a major bottleneck for large-scale production of Anopheles spp. Feeding alternatives to fresh blood are thus a priority for research, outdoor large-cage trials and control interventions. Several artificial meal compositions were tested and Anopheles oogenesis, egg laying and development into the next generation of adult mosquitoes were followed. We identified blood-substitute-diets that supported ovarian development, egg maturation and fertility as well as, low progeny larval mortality, and normal development of offspring into adult mosquitoes. The formulated diet is an effective artificial meal, free of fresh blood that mimics a vertebrate blood meal and represents an important advance for the sustainability of Anopheles mosquito rearing in captivity.Agência financiadora / Número do subsídio Bill and Melinda Gates Foundation OPP1138841 Fundacao para a Ciencia e Tecnologia GHTM - UID/Multi/04413/201 CCMAR - UID/Multi/04326/2013 UID/Multi/04326/2013 RF SFRH/BPD/89811/2012 FAPEAM, Brazil 19716.UNI472.2459.20022014info:eu-repo/semantics/publishedVersio

Systemic delivery of E6/7 siRNA using novel lipidic particles and its application with cisplatin in cervical cancer mouse models

Small interfering RNA (siRNA) shows great promise in cancer therapy, but its effectiveness in vivo still remains a crucial issue for its transition into the clinics. Although the successful use of polyethylene glycol (PEG)ylated lipidic delivery systems have already been reported, most of the formulation procedures used are labour intensive and also result in unstable end products. We have previously developed a simple yet efficient hydration-of-freeze-dried- matrix (HFDM) method to entrap siRNA within lipid particles, in which the products exhibited superior stability. Here, we show that these HFDM-formulated particles are stable in the presence of serum and can deliver siRNA efficiently to tumours after intravenous administration. Using these particles, around 50% knockdown of the target gene expression was observed in tumours. With the use of siRNA targeting the E6/7 oncogenes expressed in cervical cancer, we showed a 50% reduction in tumour size. This level of tumour growth suppression was comparable to that achieved from cisplatin at the clinically used dose. Overall, our results demonstrate the feasibility of using HFDM-formulated particles to systematically administer E6/7-targeted siRNA for cervical cancer treatment. The simplicity of preparation procedure along with superior product stability obtained from our method offers an innovative approach for the in vivo delivery of siRNA

Bayesian inversion of synthetic AVO data to assess fluid and shale content in sand-shale media

Reservoir characterization of sand-shale sequences has always challenged geoscientists due to the presence of anisotropy in the form of shale lenses or shale layers. Water saturation and volume of shale are among the fundamental reservoir properties of interest for sand-shale intervals, and relate to the amount of fluid content and accumulating potentials of such media. This paper suggests an integrated workflow using synthetic data for the characterization of shaley-sand media based on anisotropic rock physics (T-matrix approximation) and seismic reflectivity modelling. A Bayesian inversion scheme for estimating reservoir parameters from amplitude vs. offset (AVO) data was used to obtain the information about uncertainties as well as their most likely values. The results from our workflow give reliable estimates of water saturation from AVO data at small uncertainties, provided background sand porosity values and isotropic overburden properties are known. For volume of shale, the proposed workflow provides reasonable estimates even when larger uncertainties are present in AVO data

Qualitative study to understand the barriers to recruiting young people with cancer to BRIGHTLIGHT: a national cohort study in England

Objectives: BRIGHTLIGHT is a national evaluation of cancer services for teenagers and young adults in England. Following challenges with recruitment, our aim was to understand more fully healthcare professionals’ perspectives of the challenges of recruiting young people to a low-risk observational study, and to provide guidance for future recruitment processes. / Design: Qualitative. / Setting: National Health Service (NHS) hospitals in England. / Methods: Semistructured telephone interviews with a convenience sample of 23 healthcare professionals. Participants included principal investigators/other staff recruiting into the BRIGHTLIGHT study. Data were analysed using framework analysis. / Results: The emergent themes were linked to levels of research organisational management, described using the levels of social network analysis: micro-level (the individual; in this case the target population to be recruited—young people with cancer); meso-level (the organisation; refers to place of recruitment and people responsible for recruitment); and macro-level (the large-scale or global structure; refers to the wider research function of the NHS and associated policies). Study-related issues occurred across all three levels, which were influenced by the context of the study. At the meso-level, professionals’ perceptions of young people and communication between professionals generated age/cancer type silos, resulting in recruitment of either children or adults, but not both by the same team, and only in the cancer type the recruiting professional was aligned to. At the macro-level the main barrier was discordant configuration of a research service with a clinical service. / Conclusions: This study has identified significant barriers to recruitment mainly at the meso-level and macro-level, which are more challenging for research teams to influence. We suggest that interconnected whole-system changes are required to facilitate the success of interventions designed to improve recruitment. Interventions targeted at study design/management and the micro-level only may be less successful. We offer solutions to be considered by those involved at all levels of research for this population

Proliferation of hydrocarbon-degrading microbes at the bottom of the Mariana Trench

Background: The Mariana Trench is the deepest known site in the Earth’s oceans, reaching a depth of ~ 11,000m 20 at the Challenger Deep. Recent studies reveal that hadal waters harbor distinctive microbial planktonic communities. However, the genetic potential of microbial communities within the hadal zone is poorly understood. Results: Here, implementing both culture-dependent and culture-independent methods, we perform extensive analysis of microbial populations and their genetic potential at different depths in the Mariana Trench. Unexpectedly, we observed an abrupt increase in the abundance of hydrocarbon-degrading bacteria at depths > 10,400m in the Challenger Deep. Indeed, the proportion of hydrocarbon-degrading bacteria at > 10,400m is the highest observed in any natural environment on Earth. These bacteria were mainly Oleibacter, Thalassolituus, and Alcanivorax genera, all of which include species known to consume aliphatic hydrocarbons. This community shift towards hydrocarbon degraders was accompanied by increased abundance and transcription of genes involved in alkane degradation. Correspondingly, three Alcanivorax species that were isolated from 10,400m water supplemented with hexadecane were able to efficiently degrade n-alkanes under conditions simulating the deep sea, as did a reference Oleibacter strain cultured at atmospheric pressure. Abundant n-alkanes were observed in sinking particles at 2000, 4000, and 6000m (averaged 23.5 μg/gdw) and hadal surface sediments at depths of 10,908, 10,909, and 10,911m (averaged 2.3 μg/gdw). The δ2H values of n-C16/18 alkanes that dominated surface sediments at near 11,000-m depths ranged from − 79 to − 93‰, suggesting these alkanes may derive from an unknown biological source. Conclusions: These results reveal that hydrocarbon-degrading microorganisms are present in great abundance in the deepest seawater on Earth and shed a new light on potential biological processes in this extreme environment

Genome-wide analyses identify common variants associated with macular telangiectasia type 2

Idiopathic juxtafoveal retinal telangiectasis type 2 (macular telangiectasia type 2; MacTel) is a rare neurovascular degenerative retinal disease. To identify genetic susceptibility loci for MacTel, we performed a genome-wide association study (GWAS) with 476 cases and 1,733 controls of European ancestry. Genome-wide significant associations (P < 5 × 10−8) were identified at three independent loci (rs73171800 at 5q14.3, P = 7.74 × 10−17; rs715 at 2q34, P = 9.97 × 10−14; rs477992 at 1p12, P = 2.60 × 10−12) and then replicated (P < 0.01) in an independent cohort of 172 cases and 1,134 controls. The 5q14.3 locus is known to associate with variation in retinal vascular diameter, and the 2q34 and 1p12 loci have been implicated in the glycine/serine metabolic pathway. We subsequently found significant differences in blood serum levels of glycine (P = 4.04 × 10−6) and serine (P = 2.48 × 10−4) between MacTel cases and controls