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Ovarian self-incompatibility, including pre- and post-zygotic reactions, is a complex mechanism for which we still lack many details relating to its function and significance. The joint presence of ovarian self-incompatibility with style polymorphism is a rare combination that is found in the genus Narcissus. Usually, style polymorphic species have heteromorphic (diallelic and linked to style length locus) incompatibility, which prevents fertilization between individuals of the same morph, thereby helping to maintain equal proportions of floral morphs in populations. However, when present, self-incompatibility in Narcissus is not linked to style polymorphism and cross-fertilization within each morph is possible. Hence, self-incompatibility in Narcissus is of particular interest when attempting to unravel the nature of the rejection reaction and aiming to assess possible cryptic differences in the fertilization process in intra- and inter-morph crosses, which might ultimately explain the wide variation of morph-ratio in the field. We examined the breeding system of Narcissus papyraceus, a style-dimorphic species that has biased morph ratios in most of its populations. We studied pollen-tube growth in the pistil and ovule fate after experimentally controlled hand pollinations. The growth of pollen tubes in self- and intra- and inter-morph crosses was similar up to the point of micropyle penetration in both morphs but, subsequently, a pre-zygotic failure appeared to affect male and female gametophytes in selfed pistils. A high proportion of ovules from self-pollinated flowers showed signs of collapse and self-pollen tubes were blocked or behaved abnormally before entering the embryo sac. Self-incompatibility was stronger in the long-styled morph than in the short-styled morph. We did not find any conclusive sign of differential functioning between intra- and inter-morph cross-pollinations in any morph. These results enable us to rule out the possible effects of pollen–pistil interactions in N. papyraceus as a cause of morph-ratio biases and confirm the exceptional nature of the self-incompatibility mechanism in this polymorphic species. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 177, 629–643.

We have examined whether degeneration of nigrostriatal dopaminergic neurons causes dysfunction of both the basal ganglia-thalamic and cerebello-thalamic pathways. Changes in the activity of thalamic neurons receiving input from the basal ganglia or the cerebellum were examined in two models of Parkinson's disease, 6-hydroxydopamine (6-OHDA)-lesioned rats and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys. Metabolic activity of the neurons was evaluated at the cellular level by quantitative in situ hybridization, using the expression of messenger RNA for subunit I of cytochrome oxidase (COI), encoded by the mitochondrial genome, as the marker. COI mRNA expression decreased significantly in thalamocortical neurons receiving input from the substantia nigra (-50.6%) or the cerebellum (-45%) in 6-OHDA-lesioned rats compared with controls. The decrease was observed in all thalamic neurons whether or not they were retrogradely labelled with a tracer injected into the motor cortex. Similarly, COI mRNA expression decreased in projection neurons and interneurons of the thalamus receiving input from the substantia nigra (-39 and -38%, respectively), the internal pallidum (-20 and -42.4%, respectively) and the cerebellum (-36.2 and -50%, respectively) of MPTP-treated monkeys compared with controls. These decreases in COI mRNA levels show that nigrostriatal denervation results in a decrease in the metabolic activity of thalamic neurons in the territories innervated by the substantia nigra, pallidum and cerebellum, which in turn is indicative of a decrease in their neuronal activity. The decrease did not concern the entire thalamus, however, since metabolic activity was unchanged in two thalamic nuclei considered to be limbic structures, the laterodorsal nucleus in 6-OHDA-lesioned rats and the anterior nucleus in MPTP-treated monkeys. Hypoactivity of both the basal ganglia-thalamic and cerebellar-thalamic pathways might therefore be implicated in the development of parkinsonian symptoms.

Background. Although hyperuricaemia and gout are frequently found in renal transplant recipients, little has been published on the efficacy of urate-lowering therapy (ULT) in this patient population. We therefore examine the effects of allopurinol and benziodarone therapy in a cohort of renal transplant patients. Methods. We reviewed files from a cohort of 1328 patients that received renal transplantation. The selection criteria included: functioning allograft, hyperuricaemia for > 12 months or gout, ULT lasting at least 1 year and at least two control measurements after the onset of ULT. Patients on azathioprine were treated with benziodarone to avoid azathioprine-allopurinol interactions. Results. Two-hundred and seventy-nine patients fulfilled the criteria for review. They were treated with 289 courses of ULT: 100 with allopurinol (mean dose: 376 mg/day/dl/min of creatinine clearance) and 189 with benziodarone (mean dose: 73 mg day). The mean follow-up was 38 months. Both drugs were effective for the control of hyperuricaemia, but benziodarone caused greater reductions in serum uric acid levels, especially when used at mean doses of > 75 mg/day. Severe side effects were uncommon, in both the allopurinol and benziodarone groups. Conclusions. Both allopurinol and benziodarone were effective for the control of hyperuricaemia in renal transplantation. Benziodarone at doses > 75 mg/day was more effective than allopurinol in reducing serum uric acid levels and also reduced the risk of azathioprine-allopurinol interactions.

Graft compatibility has been studied in apricot (prunus armeniaca L.) grafted on Prunus cerasifera Ehrh. Two apricot cultivars, one compatible and one incompatible on this rootstock, were selected for this study. In these species incompatibility is only manifested by tree breakdown at a late phase of the tree's life. The process of graft union formation was observed for the first month following grafting. No differences were found either in the process of healing or in its kinetics. Thus, callus proliferation, callus differentiation and vascular connections are established in the same way and at the same time in both compatible and incompatible grafts. However, clear differences exist in the level of differentiation of the callus produced. While in compatible grafts, callus quickly differentiates into cambium and vascular tissue, in incompatible grafts this differentiation is not complete and a portion of the tissue evolves into a parenchymatous tissue that coexists with the differentiated vascular tissue.

Changes in the obturator of the peach ( Prunus persica) have been investigated and related to pollen tube growth in this region. At anthesis, the cells of the obturator are active and rich in starch reserves. Twelve days after anthesis these cells produce a secretion that stains for carbohydrates and for proteins. As the secretion is produced, starch vanishes from these cells and they degenerate and collapse as callose is accumulated. Secretion is independent of pollination as it takes place in a similar fashion both in pollinated and in unpollinated flowers. Pollen tube growth along the obturator surface depends on this secretion for, although pollen tubes reach the base of the style seven days after pollination, they cannot grow on the obturator until five days later, when the secretion is produced. This discontinuous secretion taking place at the obturator may provide a mechanism that controls the entrance of pollen tubes into the ovary in the peach.