Altered telomeres in tumors with ATRX and DAXX mutations     

Heaphy CM  de Wilde RF  Jiao Y  Klein AP  Edil BH  Shi C  Bettegowda C  Rodriguez FJ  Eberhart CG  Hebbar S  Offerhaus GJ  McLendon R  Rasheed BA  He Y  Yan H  Bigner DD  Oba-Shinjo SM  Marie SK  Riggins GJ  Kinzler KW  Vogelstein B  Hruban RH  Maitra A  Papadopoulos N  Meeker AK 《Science (New York, N.Y.)》2011,333(6041):425

The proteins encoded by ATRX and DAXX participate in chromatin remodeling at telomeres and other genomic sites. Because inactivating mutations of these genes are common in human pancreatic neuroendocrine tumors (PanNETs), we examined the telomere status of these tumors. We found that 61% of PanNETs displayed abnormal telomeres that are characteristic of a telomerase-independent telomere maintenance mechanism termed ALT (alternative lengthening of telomeres). All of the PanNETs exhibiting these abnormal telomeres had ATRX or DAXX mutations or loss of nuclear ATRX or DAXX protein. ATRX mutations also correlate with abnormal telomeres in tumors of the central nervous system. These data suggest that an alternative telomere maintenance function may operate in human tumors with alterations in the ATRX or DAXX genes.  相似文献   

Elevated CO₂ does not favor a fungal decomposition pathway     

Kees-Jan Van Groenigen  Johan Six  Chris Van Kessel 《Soil biology & biochemistry》2007,39(8):2168-2172

We examined the effect of prolonged elevated CO₂ on the concentration of fungal- and bacterial-derived compounds by quantifying the soil contents of the amino sugars glucosamine, galactosamine and muramic acid. Soil samples were collected from three different terrestrial ecosystems (grassland, an aspen forest and a soybean/corn agroecosystem) that were exposed to elevated CO₂ under FACE conditions for 3-10 years. Amino sugars were extracted from bulk soil and analyzed by gas chromatography. Elevated CO₂ did not affect the size or composition of the amino sugar pool in any of the systems. However, high rates of fertilizer N applications decreased the amount of fungal-derived residues in the grassland system. We suggest that these results are caused by a decrease in saprophytic fungi following high N additions. Furthermore, our findings imply that the contribution of saprophytic fungi and bacteria to SOM in the studied ecosystems is largely unaffected by elevated CO₂.  相似文献   

Effects of biocontrol bacteria and earthworms on Aphanomyces euteiches root-rot and growth of peas (Pisum sativum) studied in a pot experiment     

Jan Lagerlöf  Fredrick Ayuke  Fredrik Heyman  Johan Meijer 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2020,70(5):427-436

ABSTRACT

The role of below-ground interactions between microbial biocontrol agents and soil fauna for combatting soil-borne plant diseases have not been studied sufficiently. This study tested the hypothesis that the beneficial bacterium Bacillus velezensis UCMB5113 and the anecic earthworm Lumbricus terrestris positively influence health and growth of peas (Pisum sativum L.) infested with the pathogen Aphanomyces euteiches causing root-rot disease. A greenhouse fully factorial experiment studied the effects of A. euteches, B. velezensis and L. terrestris on the emergence, growth and health of pea plants. The factors B. velezensis and L. terrestris resulted in taller plants (p = .003 and p = .030). B. velezensis treatment resulted in a higher biomass of shoots and roots (p ≤ .001 and p = .005). The effects increased with the presence of both factors (p = .036). Earthworms reduced the disease symptoms significantly (p = .032). The decreased disease symptoms caused by the earthworms might be due to the consumption of A. euteiches (direct effect) as well as soil disturbance (indirect effect). Interactions between the microorganisms added and the earthworms were shown. B. velezensis and L. terrestris can be useful for enhancement of plant growth and for biological control of root-rot in peas.  相似文献   

Soil stress as affected by wheel load and tyre inflation pressure     

Johan Arvidsson  Thomas Keller 《Soil & Tillage Research》2007,96(1-2):284-291

The relative importance of wheel load and tyre inflation pressure on topsoil and subsoil stresses has long been disputed in soil compaction research. The objectives of the experiment presented here were to (1) measure maximum soil stresses and stress distribution in the topsoil for different wheel loads at the same recommended tyre inflation pressure; (2) measure soil stresses at different inflation pressures for the given wheel loads; and (3) measure subsoil stresses and compare measured and simulated values. Measurements were made with the wheel loads 11, 15 and 33 kN at inflation pressures of 70, 100 and 150 kPa. Topsoil stresses were measured at 10 cm depth with five stress sensors installed in disturbed soil, perpendicular to driving direction. Contact area was measured on a hard surface. Subsoil stresses were measured at 30, 50 and 70 cm depth with sensors installed in undisturbed soil. The mean ground contact pressure could be approximated by the tyre inflation pressure (only) when the recommended inflation pressure was used. The maximum stress at 10 cm depth was considerably higher than the inflation pressure (39% on average) and also increased with increasing wheel load. While tyre inflation pressure had a large influence on soil stresses measured at 10 cm depth, it had very little influence in the subsoil (30 cm and deeper). In contrast, wheel load had a very large influence on subsoil stresses. Measured and simulated values agreed reasonably well in terms of relative differences between treatments, but the effect of inflation pressure on subsoil stresses was overestimated in the simulations. To reduce soil stresses exerted by tyres in agriculture, the results show the need to further study the distribution of stresses under tyres. For calculation of subsoil stresses, further validations of commonly used models for stress propagation are needed.  相似文献   

Physical activity levels in 10- to 11-year-olds: clustering of psychosocial correlates     

Cardon G  Philippaerts R  Lefevre J  Matton L  Wijndaele K  Balduck AL  De Bourdeaudhuij I 《Public health nutrition》2005,8(7):896-903

OBJECTIVES: To evaluate gender differences for levels of physical activity, for sedentary behaviour and for psychosocial correlates in children, to evaluate whether psychosocial correlates cluster in meaningful ways and to examine whether physical activity and sedentary behaviour differ between children of clusters, differentiated by the level of perceived barriers and benefits, attitudes, social support and self-efficacy. DESIGN: Cross-sectional study using the Flemish Physical Activity Questionnaire. SETTING: Questionnaires to be filled out by the children and one of their parents, contacted through the school system. SUBJECTS: A sample of 1124 10- to 11-year-olds (579 boys and 545 girls). RESULTS: Girls were found to be less active than boys, with boys scoring better for social support, perceived benefits and self-efficacy compared with girls. The way of clustering differed between boys and girls. Boys were allocated to three clusters: one cluster with positive correlates towards physical activity, labelled 'positives'; one with negative correlates, labelled 'negatives'; and one characterised mainly by high perceived barriers, labelled 'hindered'. In both genders the highest levels of physical activity were found in the 'positives', the lowest in the 'negatives'. In girls a fourth cluster was identified, characterised mainly by low perceived barriers and low social support. Physical activity levels in the girls of this cluster, labelled 'indifferents', were the second highest. CONCLUSIONS: More research is needed to further characterise these clusters. To prevent the physical activity decline during the transition from childhood to adulthood, novel interventions need to be explored that focus on children of the clusters with the most negative correlates.  相似文献   

Breeding of transgenic orangePetunia hybrida varieties     

Johan S. N. Oud  Harrie Schneiders  Ad J. Kool  Mart Q. J. M. van Grinsven 《Euphytica》1995,84(3):175-181

Summary Flower colour is the major contributor to the total ornamental value of a flower. The combination of biochemical knowledge and genetic engineering technology has resulted in the addition of a new colour to the existing colour range ofPetunia hybrida. This has been achieved by expression of the maize dihydroflavonol-4-reductase (DFR) gene in a suitable petunia acceptor which leads to the accumulation of pelargonidin-derived pigments in flowers. The resulting flower colour, however, was a pale brick-red, which is commercially unattractive in petunia. Our objective was to produce a product suitable for commercialisation by introducing the DFR gene into our breeding material via normal sexual recombination. Although the initial transformant exhibited many negative characteristics, first analyses indicated that it was feasible to obtain material for creating commercial hybrids. Experimental hybrids based on F₄ lines were obtained with improved phenotypical expression of the orange flower colour in combination with a good general performance. In order to assess consumer-related characteristics, selected experimental hybrids were tested under field conditions. All transgenic plants had a normal appearance when compared to non-transgenic control plants. No linkage was observed between the transgenic trait and any negative characteristic. From these studies it can be concluded that through a combination of biochemistry, breeding and genetic engineering it is possible to generate unique flower colours in a cultivar with commercial potential.  相似文献   

Breeding of transgenic orange Petunia hybrida varieties     

Johan S. N. Oud  Harrie Schneiders  Ad J. Kool  Mart Q. J. M. van Grinsven 《Euphytica》1995,85(1-3):403-409

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Towards scheduled pre-parturient caesarean sections in bitches     

Kurt G. M. De Cramer  Johan O. Nöthling 《Reproduction in domestic animals》2020,55(Z2):38-48

Elective caesarean section (CS) is the safest means of delivering the litter in bitches in specific situations. Timeously performing elective pre-parturient CSs at a fixed time would be convenient and prevent emergency CSs and foetal demise. This review proposes a method of performing elective pre-parturient CSs which is safe for both the bitch and puppies. Brachycephaly, small litters and large litters, preceding litter delivered by CS and trial of labour after a preceding CS are identified as factors increasing the need for CS whereas emergency CS is identified as factor increasing foetal demise. The first day of cytological dioestrus more precisely predicts the day of onset of spontaneous parturition than the first day of the LH surge or the dates during oestrus on which progesterone (P4) first exceeds 6 nM or 16 nM. Foetal biparietal diameter at the time of onset of spontaneous parturition varies too much to accurately predict readiness for CS. During the last few days of gestation, P4 with cut-off concentrations at 15.8, 8.7 and 3.18 nM, but not plasma cortisol concentrations, hold promise as predictors of onset of parturition and when to perform pre-parturient CSs. A protocol associating medetomidine hydrochloride as premedicant with propofol as induction agent and sevoflurane as maintenance is safe for scheduled CS and yields good maternal and puppy survival rates at delivery, 2 hr and 7 days after CSs. Clinicians have to pay attention to the haematocrit of bitches at the time of cervical dilatation which is at the lower end of the normal reference ranges for non-pregnant dogs and to the decline in haematocrit during CS (as a proxy for blood loss) which is approximately 7% for both parturient (open cervix) and pre-parturient (closed cervix) CSs. Pre-parturient CSs can be scheduled and performed 57 days after onset of cytological dioestrus with puppy survival rates of 99%. Collectively, these studies provide a protocol to safely perform elective CSs in a large proportion of the obstetric population at a convenient time of the day but more research is required with larger numbers to establish whether this practice is routinely safe and safe in all breeds.  相似文献   

Biochar alters nitrogen transformations but has minimal effects on nitrous oxide emissions in an organically managed lettuce mesocosm     

Dr. Engil Isadora Pujol Pereira  Emma C. Suddick  India Mansour  Fungai N. D. Mukome  Sanjai J. Parikh  Kate Scow  Johan Six 《Biology and Fertility of Soils》2015,51(5):573-582

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When is it biological control? A framework of definitions,mechanisms, and classifications     

Stenberg  Johan A.  Sundh  Ingvar  Becher  Paul G.  Björkman  Christer  Dubey  Mukesh  Egan  Paul A.  Friberg  Hanna  Gil  José F.  Jensen  Dan F.  Jonsson  Mattias  Karlsson  Magnus  Khalil  Sammar  Ninkovic  Velemir  Rehermann  Guillermo  Vetukuri  Ramesh R.  Viketoft  Maria 《Journal of pest science》2021,94(3):665-676

Journal of Pest Science - Biological control, or biocontrol, is the exploitation of living agents (incl. viruses) to combat pestilential organisms (incl. pathogens, pests, and weeds) for diverse...  相似文献