1,250 research outputs found
Mapping quantitative physiological traits in apple ( Malus Ă domestica Borkh.)
Efficient breeding and selection of high-quality apple cultivars requires knowledge and understanding of the underlying genetics. The availability of genetic linkage maps constructed with molecular markers enables the detection and analysis of major genes and quantitative trait loci contributing to the quality traits of a genotype. A segregating population of the cross between the apple varieties 'sFiesta' (syn. 'sRed Pippin') and 'sDiscovery' has been observed over three years at three different sites in Switzerland and data on growth habit, blooming behaviour, juvenile period and fruit quality has been recorded. QTL analyses were performed, based on a genetic linkage map consisting of 804 molecular markers and covering all 17 apple chromosomes. With the maximum likelihood based interval mapping method, the investigated complex traits could be dissected into a number of QTLs affecting the observed characters. Genomic regions participating in the genetic control of stem diameter, plant height increment, leaf size, blooming time, blooming intensity, juvenile phase length, time of fruit maturity, number of fruit, fruit size and weight, fruit flesh firmness, sugar content and fruit acidity were identified and compared with previously mapped QTLs in apple. Although 'sDiscovery' fruit displayed a higher acid content, both acidity QTLs were attributed to the sweeter parent 'sFiesta'. This indicated homozygosity at the acidity loci in 'sDiscovery' preventing their detection in the progeny due to the lack of segregatio
Molecular markers linked to the apple scab resistance gene Vbj derived from Malus baccata jackii
Breeding for scab-resistant apple cultivars by pyramiding several resistance genes in the same genetic background is a promising way to control apple scab caused by the fungus Venturia inaequalis. To achieve this goal, DNA markers linked to the genes of interest are required in order to select seedlings with the desired resistance allele combinations. For several apple scab resistance genes, molecular markers are already available; but until now, none existed for the apple scab resistance gene Vbj originating from the crab apple Malus baccata jackii. Using bulk segregant analysis, three RAPD markers linked to Vbj were first identified. These markers were transformed into more reliable sequence-characterised amplified region (SCAR) markers that proved to be co-dominant. In addition, three SSR markers and one SCAR were identified by comparing homologous linkage groups of existing genetic maps. Discarding plants showing genotype-phenotype incongruence (GPI plants) plants, a linkage map was calculated. Vbj mapped between the markers CH05e03 (SSR) and T6-SCAR, at 0.6cM from CH05e03 and at 3.9cM from T6-SCAR. Without the removal of the GPI plants, Vbj was placed 15cM away from the closest markers. Problems and pitfalls due to GPI plants and the consequences for mapping the resistance gene accurately are discussed. Finally, the usefulness of co-dominant markers for pedigree analysis is also demonstrate
Administration of Steroids in Pediatric Cardiac Surgery: Impact on Clinical Outcome and Systemic Inflammatory Response
Cardiopulmonary bypass (CPB) is associated with a systemic inflammatory response. Pre-bypass steroid administration may modulate the inflammatory response, resulting in improved postoperative recovery. We performed a prospective study in the departments of cardiovascular surgery and pediatric intensive care medicine of two university hospitals that included 50 infants who underwent heart surgery. Patients received either prednisolone (30 mg/kg) added to the priming solution of the cardiopulmonary bypass circuit (steroid group) or no steroids (nonsteroid group). Clinical outcome parameters include therapy with inotropic drugs, oxygenation, blood lactate, glucose, and creatinine, and laboratory parameters of inflammation include leukocytes, C-reactive protein, and interleukin-8. Postoperative recovery (e.g., the number, dosage, and duration of inotropic drugs as well as oxygenation) was similar in patients treated with or without steroids when corrected for the type of cardiac surgery performed. After CPB, there was an inflammatory reaction, especially in patients with a long CPB time. Postoperative plasma levels of interleukin-8 were correlated with the duration of CPB time (r = 0.62, p < 0.001). Administration of steroids had no significant impact on the laboratory parameters of inflammation. Administration of prednisolone into the priming solution of the CPB circuit had no measurable influence on postoperative recovery and did not suppress the inflammatory respons
Pivotal role of families in doctorâpatient communication in oncology: a qualitative study of patients, their relatives and cancer clinicians
Families are a unique source of support for many cancer patients. Most advanced communication skills training for oncologists are patient centred and do not cover interactions with family members. The current study used in-depth qualitative interviews of patients, relatives and cancer clinicians with thematic analysis to explore the role of family members in the communication process. Forty-one participants included 10 cancer patients, 10 relatives ensuring proportionate representation of both gender and primary cancer site and 21 doctors representing both medical and surgical oncology. Nineteen of 20 patients and relatives wanted an "open and honest" discussion with their doctors. All patients, relatives and doctors preferred involvement of the family at most stages of cancer treatment. Five themes were identified in relation to communication with family members. The participants highlighted the "importance of family for physical and psychological care," they emphasised the need to "balance patient autonomy and relatives desire to be protective" using varied "negotiating strategies" that are influenced by "socioeconomic circumstances of both patient and family." The doctor-patient-relative communication process was not static with preferences changing over time. The data suggests that communication skills training of cancer clinicians should incorporate modules on better communication with relatives
Identification of functional apple scab resistance gene promoters
Apple scab (Venturia inaequalis) is one of the most damaging diseases affecting commercial apple production. Some wild Malus species possess resistance against apple scab. One gene, HcrVf2, from a cluster of three genes derived from the wild apple Malus floribunda clone 821, has recently been shown to confer resistance to apple scab when transferred into a scab-susceptible apple variety. For this proof-of-function experiment, the use of the 35S promoter from Cauliflower mosaic virus was reliable and appropriate. However, in order to reduce the amount of non-plant DNA in genetically modified apple to a minimum, with the aim of increasing genetically modified organism acceptability, these genes would ideally be regulated by their own promoters. In this study, sequences from the promoter region of the three members of the HcrVf gene family were compared. Promoter constructs containing progressive 5Ⲡdeletions were prepared and used for functional analyses. Qualitative assessment confirmed promoter activity in apple. Quantitative promoter comparison was carried out in tobacco (Nicotiana glutinosa) and led to the identification of several promoter regions with different strengths from a basal level to half the strength of the 35S promoter from Cauliflower mosaic viru
Tree allocation dynamics beyond heat and hot drought stress reveal changes in carbon storage, belowground translocation and growth
Heatwaves combined with drought affect tree functioning with as yet undetermined legacy effects on carbon (C) and nitrogen (N) allocation.
We continuously monitored shoot and root gas exchange, δ13CO2 of respiration and stem growth in well-watered and drought-treated Pinus sylvestris (Scots pine) seedlings exposed to increasing daytime temperatures (max. 42°C) and evaporative demand. Following stress release, we used 13CO2 canopy pulse-labeling, supplemented by soil-applied 15N, to determine allocation to plant compartments, respiration and soil microbial biomass (SMB) over 2.5 wk.
Previously heat-treated seedlings rapidly translocated 13C along the long-distance transport path, to root respiration (Rroot; 7.1 h) and SMB (3 d). Furthermore, 13C accumulated in branch cellulose, suggesting secondary growth enhancement. However, in recovering drought-heat seedlings, the mean residence time of 13C in needles increased, whereas C translocation to Rroot was delayed (13.8 h) and 13C incorporated into starch rather than cellulose. Concurrently, we observed stress-induced low N uptake and aboveground allocation.
C and N allocation during early recovery were affected by stress type and impact. Although C uptake increased quickly in both treatments, drought-heat in combination reduced the aboveâbelowground coupling and starch accumulated in leaves at the expense of growth. Accordingly, C allocation during recovery depends on phloem translocation capacity
Risk-Reducing Salpingo-Oophorectomy and the Use of Hormone Replacement Therapy Below the Age of Natural Menopause: Scientific Impact Paper No. 66
This paper deals with the use of hormone replacement therapy (HRT) after the removal of fallopian tubes and ovaries to prevent ovarian cancer in premenopausal high risk women. Some women have an alteration in their genetic code, which makes them more likely to develop ovarian cancer. Two well-known genes which can carry an alteration are the BRCA1 and BRCA2 genes. Examples of other genes associated with an increased risk of ovarian cancer include RAD51C, RAD51D, BRIP1, PALB2 and Lynch syndrome genes. Women with a strong family history of ovarian cancer and/or breast cancer, may also be at increased risk of developing ovarian cancer. Women at increased risk can choose to have an operation to remove the fallopian tubes and ovaries, which is the most effective way to prevent ovarian cancer. This is done after a woman has completed her family. However, removal of ovaries causes early menopause and leads to hot flushes, sweats, mood changes and bone thinning. It can also cause memory problems and increases the risk of heart disease. It may reduce libido or impair sexual function. Guidance on how to care for women following preventative surgery who are experiencing early menopause is needed. HRT is usually advisable for women up to 51Â years of age (average age of menopause for women in the UK) who are undergoing early menopause and have not had breast cancer, to minimise the health risks linked to early menopause. For women with a womb, HRT should include estrogen coupled with progestogen to protect against thickening of the lining of the womb (called endometrial hyperplasia). For women without a womb, only estrogen is given. Research suggests that, unlike in older women, HRT for women in early menopause does not increase breast cancer risk, including in those who are BRCA1 and BRCA2 carriers and have preventative surgery. For women with a history of receptor-negative breast cancer, the gynaecologist will liaise with an oncology doctor on a case-by-case basis to help to decide if HRT is safe to use. Women with a history of estrogen receptor-positive breast cancer are not normally offered HRT. A range of other therapies can be used if a woman is unable to take HRT. These include behavioural therapy and non-hormonal medicines. However, these are less effective than HRT. Regular exercise, healthy lifestyle and avoiding symptom triggers are also advised. Whether to undergo surgery to reduce risk or not and its timing can be a complex decision-making process. Women need to be carefully counselled on the pros and cons of both preventative surgery and HRT use so they can make informed decisions and choices
Tile Number and Space-Efficient Knot Mosaics
In this paper we introduce the concept of a space-efficient knot mosaic. That
is, we seek to determine how to create knot mosaics using the least number of
non-blank tiles necessary to depict the knot. This least number is called the
tile number of the knot. We determine strict bounds for the tile number of a
knot in terms of the mosaic number of the knot. In particular, if is the
tile number of a prime knot with mosaic number , then if is even and if is odd. We also
determine the tile number of several knots and provide space-efficient knot
mosaics for each of them.Comment: The original version of this article was split into two articles
during refereein
The \u3csup\u3e18\u3c/sup\u3eO-Signal Transfer from Water Vapour to Leaf Water and Assimilates Varies Among Plant Species and Growth Forms
The 18O signature of atmospheric water vapour (δ18OV) is known to be transferred via leaf water to assimilates. It remains, however, unclear how the 18Oâsignal transfer differs among plant species and growth forms. We performed a 9âhr greenhouse fog experiment (relative humidity ⼠98%) with 18Oâdepleted water vapour (â106.7â°) on 140 plant species of eight different growth forms during daytime. We quantified the 18Oâsignal transfer by calculating the mean residence time of O in leaf water (MRTLW) and sugars (MRTSugars) and related it to leaf traits and physiological drivers. MRTLW increased with leaf succulence and thickness, varying between 1.4 and 10.8 hr. MRTSugars was shorter in C3 and C4 plants than in crassulacean acid metabolism (CAM) plants and highly variable among species and growth forms; MRTSugars was shortest for grasses and aquatic plants, intermediate for broadleaf trees, shrubs, and herbs, and longest for conifers, epiphytes, and succulents. Sucrose was more sensitive to δ18OV variations than other assimilates. Our comprehensive study shows that plant species and growth forms vary strongly in their sensitivity to δ18OV variations, which is important for the interpretation of δ18O values in plant organic material and compounds and thus for the reconstruction of climatic conditions and plant functional responses
- âŚ