Mapping and QTL analysis of horticultural traits in a narrow cross in cucumber (Cucumis sativus L.) using random-amplified polymorphic DNA markers

An 80-point genetic map [77 random-amplified polymorphic DNAs (RAPD), F (female sex expression), de (determinate), and ll (little leaf)] was constructed from a narrow cross in cucumber using the determinate, gynoecious, standard-sized leaf line G421 and the indeterminate, monoecious, little leaf line H-19. The map defined nine linkage groups and spanned ca. 600 cM with an average distance between markers of 8.4 ± 9.4 cM. The RAPD loci BC-551 and BC-592 were found to flank ll at 3.4 and 12.2 cM, respectively. The locus OP-L18-2 was linked (16 cM) to de, and the F locus was flanked by markers at 44 and 31 cM. One-hundred F3 families were used to identify quantitative trait loci (QTL) for sex expression, main stem length, number of lateral branches, days to anthesis, fruit number and weight, fruit length and diameter, and fruit length: diameter ratio in two replicated test locations (Wisconsin and Georgia). QTL on linkage group B explained major portions (R2 = ca. 2 to 74%) of the variation observed for sex expression, main stem length, lateral branch number, and fruit diameter (LOD = 2.1 to 29.8). Although ca. 62 to 74% of the variation for sex expression was associated with a putative QTL spanning the F locus (OP-AJ-2 to F and F to de), other regions (three) of the genome were important for the determination of sex in the F3 families examined depending upon environment. The number of genomic regions affecting main stem length (five) and number of lateral branches (three) coincided with expectations as determined by calculations of minimum number of genes in previous studies. Evaluation of QTL associated with several fruit number determinants of early, first-harvest yield demonstrating additive genetic variance (i.e., sex expression, main stem length, and number of laterals) suggests that marker-assisted selection may have utility for the development of determinate, multiple lateral branching germplasm suited for once-over mechanical harvesting in this population.     

Electrical and adaptive properties of rod photoreceptors in bufo marinus. II. Effects of cyclic nucleotides and protaglandins

Substances known to alter cyclic nucleotide levels in cells were applied to the isolated toad retina and effects on rod electrical and adaptive behavior were studied. The retina was continually superfused in control ringer’s or ringer’s containing one or a combination of drugs, and rod activity was recorded intracellularly. Superfusion with cGMP, Bu(2)GMP, isobutylmethylxanthine (IBMX; a phosphodiesterase inhibitor), or PGF(2α) (a prostaglandin) caused effects in rods that closely match those observed when extracellular Ca(2+) levels were lowered. For example, short exposures (up to 6 min) of the retina to these substances caused depolarization of the membrane potential, increase in response amplitudes, and some changes in waveform; but under dark-adapted or partially light-adapted conditions receptor sensitivity was virtually unaffected. That is, the position of the V-log I curve on the intensity axis was determined by the prevailing light level, not by drug level. These drugs, like lowered extracellular Ca(2+), also decreased the period of receptor saturation after a bright-adapting flash, resulting in an acceleration of the onset of membrane and sensitivity recovery during dark adaptation.

Long-term (6-15 min) exposure of a dark-adapted retina to 5 mM IBMX or a combination of IBMX and cGMP caused a loss of response amplitude and a desensitization of the rods that was similar to that observed in rods after a long-term low Ca(2+) (10(-9)M) treatment. Application of high (3.2 mM) Ca(2+) to the retina blocked the effects of applied Bu(2)cGMP. PGE(1) superfusion mimicked the effects of increasing extracellular Ca(2+). The results show that increased cGMP and lowered Ca(2+) produce similar alterations in the electrical activity of rods. These findings suggest that Ca(2+) and cGMP are interrelated messengers. We speculate that low Ca(2+) may lead to increased intracellular cGMP, and/or that applied cGMP, and/or that applied cGMP may lower cytosol Ca(2+), perhaps by stimulating Ca(2+)- ATPase pumps in the outer segment.

     

Stent implantation in acute myocardial infarction using a heparin-coated stent: a pilot study as a preamble to a randomized trial comparing balloon angioplasty and stenting

Preliminary experience with primary stenting in myocardial infarction has suggested a greater benefit in clinical outcome than has been obtained with direct balloon angioplasty. However, subacute thrombosis (SAT) remains a limitation for this new mode of therapy. In the BENESTENT II Pilot and main trials, the incidence of SAT with the heparin-coated Palmaz-Schatz stent was only 0.15%. Therefore, as a preamble to a large randomized trial, the feasibility and safety of the use of the Heparin-Coated Palmaz-Schatz trade mark Stent in Acute Myocardial Infarction (AMI) was tested in 101 patients enrolled between April and September 1996 in 18 clinical centres. In 101 stent-eligible AMI patients, as dictated by protocol, a heparin-coated stent was implanted. The primary objectives were to determine the in-hospital incidence of major adverse cardiac events (MACE: death, MI, target lesion revascularization) and bleeding complications, while the secondary objectives were the procedural success rate and the MACE, the restenosis and reocclusion rates at 6.5 months. Stent implantation (n 3 129 stents) was successful in 97 patients of the 101 who were included in this trial. During their hospital stay, two patients died and no patient experienced re-infarction, ischaemia prompting re-PTCA or CABG. Four patients suffered a bleeding complication, three major and one minor, of whom three required surgical repair. At 210 days follow-up, 81% of the patients were event free. At 6.5 months restenosis was documented in 18% of the 88 patients who underwent follow-up angiography, including three total occlusions. The results, both with respect to QCA and the occurrence of MACE, compare favourably with studies using elective stenting in both stable and unstable angina patients. As a result of this pilot study, a large randomized trial comparing direct balloon angioplasty with direct stenting in 900 patients with AMI was initiated in December 1996.     

Genetic conflict outweighs heterogametic incompatibility in the mouse hybrid zone?

Background  

The Mus musculus musculus/M. m. domesticus contact zone in Europe is characterised by sharp frequency discontinuities for sex chromosome markers at the centre of wider clines in allozyme frequencies.     

Changes in maternal risk factors and their association with changes in cesarean sections in Norway between 1999 and 2016: A descriptive population-based registry study

BackgroundIncreases in the proportion of the population with increased likelihood of cesarean section (CS) have been postulated as a driving force behind the rise in CS rates worldwide. The aim of the study was to assess if changes in selected maternal risk factors for CS are associated with changes in CS births from 1999 to 2016 in Norway.Methods and findingsThis national population-based registry study utilizes data from 1,055,006 births registered in the Norwegian Medical Birth Registry from 1999 to 2016. The following maternal risk factors for CS were included: nulliparous/≥35 years, multiparous/≥35 years, pregestational diabetes, gestational diabetes, hypertensive disorders, previous CS, assisted reproductive technology, and multiple births. The proportion of CS births in 1999 was used to predict the number of CS births in 2016. The observed and predicted numbers of CS births were compared to determine the number of excess CS births, before and after considering the selected risk factors, for all births, and for births stratified by 0, 1, or >1 of the selected risk factors. The proportion of CS births increased from 12.9% to 16.1% (+24.8%) during the study period. The proportion of births with 1 selected risk factor increased from 21.3% to 26.3% (+23.5%), while the proportion with >1 risk factor increased from 4.5% to 8.8% (+95.6%). Stratification by the presence of selected risk factors reduced the number of excess CS births observed in 2016 compared to 1999 by 67.9%. Study limitations include lack of access to other important maternal risk factors and only comparing the first and the last year of the study period.ConclusionsIn this study, we observed that after an initial increase, proportions of CS births remained stable from 2005 to 2016. Instead, both the size of the risk population and the mean number of risk factors per birth continued to increase. We observed a possible association between the increase in size of risk population and the additional CS births observed in 2016 compared to 1999. The increase in size of risk population and the stable CS rate from 2005 and onward may indicate consistent adherence to obstetric evidence-based practice in Norway.

In a population-based study, Ingvild Nedberg and colleagues investigate the relationship between maternal risk factors and changes in rates of cesarean section births in Norway.     

Human lymphocyte glucocorticoid receptors reside mainly in the cytoplasm

Karyoplasts prepared from human lymphocytes by treatment with cytochalasin B or lymphocytes permeabilized with digitonin contain only 25-40% of the total cellular glucocorticoid binding activity. The presented results thus support the original concept that unfilled steroid hormone receptors are mainly cytoplasmic.