Dynein Heavy Chain, Encoded by Two Genes in Agaricomycetes, Is Required for Nuclear Migration in Schizophyllum commune.

The white-rot fungus Schizophyllum commune (Agaricomycetes) was used to study the cell biology of microtubular trafficking during mating interactions, when the two partners exchange nuclei, which are transported along microtubule tracks. For this transport activity, the motor protein dynein is required. In S. commune, the dynein heavy chain is encoded in two parts by two separate genes, dhc1 and dhc2. The N-terminal protein Dhc1 supplies the dimerization domain, while Dhc2 encodes the motor machinery and the microtubule binding domain. This split motor protein is unique to Basidiomycota, where three different sequence patterns suggest independent split events during evolution. To investigate the function of the dynein heavy chain, the gene dhc1 and the motor domain in dhc2 were deleted. Both resulting mutants were viable, but revealed phenotypes in hyphal growth morphology and mating behavior as well as in sexual development. Viability of strain Δdhc2 is due to the higher expression of kinesin-2 and kinesin-14, which was proven via RNA sequencing.

Neuromuscular control of balancing side contacts in unilateral biting and chewing.

When jaw gape in unilateral biting or chewing narrows, the working/balancing side activity ratio (W/B ratio) of masseter muscles increases due to decrease of balancing side (BS) activity. This was interpreted as a neuromuscular strategy to delimit the impact of BS contacts during chewing. To test this hypothesis, we studied whether W/B ratios are associated with incidence of BS tooth contacts. In 40 healthy subjects, bilateral masseter activity was recorded during unilateral biting with different jaw gapes and during various chewing tasks. Biting was performed with absence and with deliberate avoidance or generation of BS tooth contacts. Subjects were divided into three groups according to jaw gapes of 2, 1, and 0.5 mm for which BS contact was first noticed in strong biting. The smaller this gape was, the higher were the mean W/B ratios. In biting with contact avoidance, the W/B ratios in each group increased with decreasing gape. In biting with generation of BS contacts, W/B ratios were smaller than with contact avoidance. W/B ratios in chewing with minimum interocclusal distances below 0.5 mm were bigger than in biting with contact generation and were mostly bigger than in biting with contact avoidance. The findings confirm that increasing the masseter W/B ratio is a neuromuscular measure suitable to avoid BS contacts and support the idea that motor control uses jaw gape-related activation to limit the impact of BS contacts. Clarification of this protection mechanism might contribute to uncover the etiology of functional disorders and occlusal malfunctions.

Ras GTPase-activating protein gap1 of the homobasidiomycete Schizophyllum commune regulates hyphal growth orientation and sexual development.

The white rot fungus Schizophyllum commune is used for the analysis of mating and sexual development in homobasidiomycete fungi. In this study, we isolated the gene gap1 encoding a GTPase-activating protein for Ras. Disruption of gap1 should therefore lead to strains accumulating Ras in its activated, GTP-bound state and to constitutive Ras signaling. Haploid Deltagap1 monokaryons of different mating types did not show alterations in mating behavior in the four different mating interactions possible in fungi expressing a tetrapolar mating type system. Instead, the growth rate in Deltagap1 monokaryons was reduced by ca. 25% and ca. 50% in homozygous Deltagap1/Deltagap1 dikaryons. Monokaryons, as well as homozygous dikaryons, carrying the disrupted gap1 alleles exhibited a disorientated growth pattern. Dikaryons showed a strong phenotype during clamp formation since hook cells failed to fuse with the peg beside them. Instead, the dikaryotic character of the hyphae was rescued by fusion of the hooks with nearby developing branches. Deltagap1/Deltagap1 dikaryons formed increased numbers of fruitbody primordia, whereas the amount of fruitbodies was not raised. Mature fruitbodies formed no or abnormal gills. No production of spores could be observed. The results suggest Ras involvement in growth, clamp formation, and fruitbody development.

Three-year follow-up after intracoronary beta-radiation therapy for in-stent restenosis.

BACKGROUND: Most studies that proved intracoronary radiation therapy (IRT) to be highly effective to reduce recurrent restenosis after treatment of in-stent restenosis (ISR) have looked at time periods up to 12 months. Whether the beneficial effect from radiation is sustained during long-term follow-up remains a concern. This study sought to evaluate the effectiveness of IRT using a beta-emitter during a 3-year follow-up period. METHODS: One hundred twenty-eight consecutive symptomatic patients (mean age, 63 +/- 11 years) with 134 in-stent restenotic lesions were treated for ISR with IRT (noncentred beta-emitter, Novoste; radiation dosis 21.1 +/- 3.1 Gy). Six-month angiographic follow-up was obtained in 104 patients (81%) with 105 lesions (78%). All patients underwent 36-month clinical follow-up. RESULTS: Six-month angiographic restenosis rate was 22% in stent (29% in lesion) with an in-stent late loss of 0.49 +/- 0.62 mm. Target lesion resvascularization (TLR) at 6-month follow-up was performed in 23 cases (18%). MACE (death, myocardial infarction, and target vessel revascularisation) was observed in 24 patients (19%). At 36-month follow-up, TLR increased to 36 cases (28%) and MACE was observed in 47 patients (37%). In a multivariate analysis, minimal lumen diameter before treatment of ISR using IRT was the only predictor of recurrent TLR at 36 months (OR = 0.131; 95% CI, 0.068-0.254; p = 0.002). In a subgroup of patients (N = 15) without restenosis at 6-month angiography but with clinically driven recurrent late angiography (mean, 18 +/- 7 months); in-lesion late loss increased from 0.47 +/- 0.54 mm at 6 months to 1.27 +/- 0.76 mm at repeated angiography (p = 0.005). CONCLUSION: There is a considerable number of delayed recurrent restenosis post IRT for ISR. This is due to ongoing late loss more than 6-month post IRT. The minimal lumen diameter before IRT predicts the need for recurrent TLR at 36 months.

Treatment of in-stent restenosis using a paclitaxel-eluting stent: acute results and long-term follow-up of a matched-pair comparison with intracoronary beta-radiation therapy.

AIMS: Intracoronary radiation therapy (ICR) has significantly improved the long-term outcome after treatment of diffuse in-stent restenosis (ISR). The efficacy of drug eluting stents in this setting remains less well defined. This matched-pair analysis compared the procedural and long-term clinical and angiographic outcome after treatment of diffuse ISR using a paclitaxel-eluting stent (PES) with intracoronary beta-radiation therapy. METHODS AND RESULTS: Twenty-two patients receiving 25 PES (ACHIEVE, Cook, 3.1 microg paclitaxel per square millimeter, non-polymer based coating) for ISR underwent 6-month angiographic and 12-month clinical follow-up. From a database including 141 patients (174 lesions) undergoing intracoronary beta-radiation for ISR, 25 lesions (25 patients) were pair-matched with the former group for lesion length and vessel size. PES implantation and ICR were successful in all patients with a significantly lower postprocedural in-stent diameter stenosis in the PES group (8+/-12% vs. 18+/-8%, p < 0.01). Angiographic binary in-lesion restenosis at 6 month was 20% (5/25 lesions) in the PES group and 16% (4/25) in the ICR group (p = 1.0). PES implantation resulted in significantly higher in-stent MLD at FU (2.10+/-0.71 vs. 1.75+/-0.36, p = 0.03) and a higher in-stent net gain (PES: 1.19+/-0.69, ICR: 0.84+/-0.49, p = 0.04). Two patients in the PES group and 6 patients in the ICR group experienced a target lesion revascularisation at 12-month follow-up (p = 0.25). CONCLUSION: Implantation of a non-polymer based paclitaxel-elution stent and conventional ICR therapy for complex ISR lead to comparable acute and long-term clinical and angiographic follow-up results.