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David Seaby 《Compost science & utilization》2013,21(4):50-55
Two structure meters are described, results from which had a high mutual correlation. Both gave reproducible results. The device which was simplest to use was given extensive field testing by three compost makers in Northern Ireland and was judged to have provided useful additional measurements to help maintain compost quality and conserve raw materials. Yields gathered from commercial growers over a three year period indicated that structure had an influence on yield and that there was an optimum structure above and below which, yields declined. It was also found that nitrogen (N) and structure (S) were significantly correlated. The evidence that S (as measured) influenced yield could thus have been confounded by N unless the latter was allowed for. Consequently, the evidence for the correlation between S and yield was that the product of dry matter × N × S was more strongly correlated with yield than dry matter (DM) × N alone. In previous work, (Seaby 1995) it was found that DM × N had an optimum, above which yields reached a plateau and then declined, similarly it was found that DM × N × S also appeared to have an optimum value. It is postulated that an underlying reason for this, is that yield is ultimately limited by the ratio of casing area to compost weight which is relatively low with the bag method of mushroom production. 相似文献
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Interspecies somatic cell nuclear transfer (interspecies SCNT) has been explored in many domestic and non‐domestic animal species. However, problems arise during the development of these embryos, which may be related to species‐specific differences in nuclear–cytoplasmic communication. The objectives of this study were to investigate the possibility of producing bison embryos in vitro using interspecies SCNT and assess the developmental potential of these embryos. Treatment groups consisted of cattle in vitro fertilization (IVF) and cattle SCNT as controls and wood bison SCNT, plains bison SCNT and wisent SCNT as experimental groups. Cleavage and blastocyst rates were assessed, and blastocyst quality was determined using total cell number, apoptotic incidence and relative quantification of mitochondria‐related genes NRF1, MT‐CYB and TFAM. These results indicate that embryos can be produced by interspecies SCNT in all bison species/subspecies (13.34–33.54% blastocyst rates). Although increased incidence of apoptosis was observed in bison SCNT blastocysts compared to cattle SCNT controls (10.45–12.69 vs 8.76, respectively) that corresponded with significantly lower cell numbers (80–87 cells vs >100 cells, respectively), no major differences were observed in the expression of NRF1, MT‐CYB and TFAM. This study is the first to report the production of bison embryos by interspecies SCNT. Blastocyst development in all three bison species/subspecies was greater than the rates obtained in previous studies by IVF, which supports the potential role of SCNT for in vitro embryo production in this species. Yet, further investigation of developmental competence and the factors influencing blastocyst quality and viability is required. 相似文献
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Summary Mixing of antiserum and potato leaf sap during serological agglutination tests was carried out on a series of small mirros
attached to a thick glass rectangle. This was oscillated 20° either side of the horizontal at 22 cycles per minute on a platform
powered by a small geared down electric motor. Observations were made using oblique illumination. The device improves the
sensitivity of the test, reduces the time required, and eliminates the use of large numbers of microscope slides. 相似文献
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Studies to date have shown that bison embryo development in vitro is compromised with few embryos developing to the blastocyst stage. The aim of this study was to use bison-cattle hybrid embryos, an interspecific cross that is known to result in live offspring in vivo, as a model for assessing species-specific differences in embryo development in vitro. Cattle oocytes fertilized with cattle, plains bison and wood bison sperm were assessed for various developmental parameters associated with embryo quality, including cell number, apoptosis and ATP content. Decreased development to the blastocyst stage was observed in hybrid wood bison embryos compared with the other treatment groups. Although both wood bison and plains bison hybrid blastocysts had significantly lower cell numbers than cattle blastocysts, only wood bison hybrid blastocysts had a greater incidence of apoptosis than cattle blastocysts. Among the treatment groups, ATP levels and expression profiles of NRF1, TFAM, MT-CYB, BAX and BCL2 were not significantly different in both 8- to 16-cell stage and blastocyst stage embryos. These data provide evidence of decreased developmental competence in the wood bison hybrid embryos, owing to inadequate culture conditions that have increased apoptotic events. 相似文献
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David Seaby 《Compost science & utilization》2013,21(4):56-65
Casing is the ‘soil’ layer applied to compost on which primordia known as pins form after airing, a proportion of which develop into mushrooms during several flushes or bursts of growth, usually occurring every six to ten days. Brown sphagnum moss peat casing (SP) was compared with black fen peat casing (BP) and gave significantly higher yields for each of five, potentially high-yielding composts, but a similar yield for a single potentially low-yielding compost. At the end of cropping, BP casing, which had poor structure, had permanently shrunk to a larger degree than SP casing. BP casing was also found more difficult to re-hydrate on the high-yielding composts and from the second flush onwards, these mushrooms had a progressively higher dry matter. This contrasted with those from the SP casing which had a progressively lower dry matter. In Northern Ireland, in the last decade, progressively more BP casing has been used. The likelihood that this has lowered potential yields is discussed.In another experiment, eight casings were tested on a single compost, four contained 50% SP casing (as used for the control) plus 50% spent-mushroom-compost (SMC) the latter having been eluted with either water or citric acid and then either pasteurized or not. The three casings which comprised eluted SMC only were clay-like in consistency and mixing them with SP casing reduced pore-space. All casings initially contained a similar moisture percentage (v/v); however, during cropping they demonstrated a wide range of resistance to being re-hydrated at watering. This repellence was scored ‘blind’ and found to be inversely correlated with a measure of casing water uptake potential and with the percentage by volume of pore space contained within the casing, both measurements having been made at the start of the experiment. Water repellence was significantly, inversely correlated with mushroom moisture content and with yield. Casing water uptake potential and pore space were significantly correlated with mushroom moisture content and with yield. Yield was significantly correlated with mushroom moisture content and also with the number of primordia developing to pea size. 相似文献
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D. Seaby 《Forest Pathology》1977,7(3):186-188
At least three quarters of the sites of brash fires in a mainly coniferous area on peat in Co Tyrone, Northern Ireland were clonised by Rhizina undulata. On each of these sites an average of eight newly planted Picea abies died within five years. No more deaths were recorded during a further three years. Deaths of Picea abies seldom occurred where there had been no fire or on fire sites on hardwood stumps in the same area. 相似文献
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