Degradation of chloroplast DNA during natural senescence of maple leaves     

Fulgosi H  Jezic M  Lepedus H  Stefanic PP  Curkovic-Perica M  Cesar V 《Tree physiology》2012,32(3):346-354

The fate of chloroplast DNA (cpDNA) during plastid development and conversion between various plastid types is still not very well understood. This is especially true for the cpDNA found in plastids of naturally senescing leaves. Here, we describe changes in plastid nucleoid structure accompanied with cpDNA degradation occurring during natural senescence of the free-growing deciduous woody species Acer pseudoplatanus L. Natural senescence was investigated using three types of senescing leaves: green (G), yellow-green (YG) and yellow (Y). The extent of senescence was evaluated at the level of photosynthetic pigment degradation, accumulation of starch and plastid ultrastructure. Determination of cpDNA amount was carried out by in planta visualization with 4,6-diamidino-2-phenylindole, by Southern hybridization, and by dot-blot using an rbcL gene probe. During natural senescence, plastid nucleoids undergo structural rearrangements accompanied by an almost complete loss of cpDNA. Furthermore, senescence-associated protein components exhibiting strong binding to an ～10kbp rbcL-containg cpDNA fragment were identified. This interaction might be important for rbcL expression and Rubisco degradation during the course of natural senescence in trees.  相似文献   

Effect of restricted suckling on milk yield,milk composition and udder health in cows and behaviour and weight gain in calves,in dual-purpose cattle in the tropics     

Fröberg S  Aspegren-Güldorff A  Olsson I  Marin B  Berg C  Hernández C  Galina CS  Lidfors L  Svennersten-Sjaunja K 《Tropical animal health and production》2007,39(1):71-81

The study was conducted to evaluate the effects of restricted suckling (RS) in dual-purpose cows and calves compared to artificial rearing (AR). Twelve Holstein-Zebu cows with calves were assigned to each treatment. Cows were milked once daily in the morning with calves present to stimulate milk let-down. RS calves suckled 30 min after milking and 30 min in the afternoon, whereas AR calves were milk-fed from nipple bottles. The daily saleable milk yield was higher in RS than in AR cows (p < 0.01; 7.44 vs 6.50 kg/day), whereas RS cows had lower milk-fat content (p < 0.001). AR cows had higher California Mastitis Test scores (p < 0.001) and lower lactose content (p < 0.001) compared to RS cows, which indicates an improved udder health in RS cows. AR calves displayed more ‘cross-suck’ during suckling/milk feeding (p < 0.001) and during observations of general behaviour (p < 0.05), and more ‘lick and sniff interior’ during milking (p < 0.05) and suckling/milk feeding (p < 0.01), compared to RS calves. During observations of general behaviour the RS calves were more often observed to ‘walk’ (p < 0.01) and ‘lick self’ (p < 0.05) and less frequently to ‘eat concentrate’ (p < 0.05) than AR calves. Results support the hypothesis that RS increases milk yield, influences milk composition and improves udder health in cows, and decreases abnormal sucking in calves.  相似文献   

Volatile release from aqueous solutions under dynamic headspace dilution conditions.     

M Marin  I Baek  A J Taylor 《Journal of agricultural and food chemistry》1999,47(11):4750-4755

Static equilibrium was established between the gas phase (headspace) and an unstirred aqueous phase in a sealed vessel. The headspace was then diluted with air to mimic the situation when a container of food is opened and the volatiles are diluted by the surrounding air. Because this first volatile signal can influence overall flavor perception, the parameters controlling volatile release under these conditions are of interest. A mechanistic model was developed and validated experimentally. Release of compounds depended on the air-water partition coefficient (K(aw)) and the mass transport in both phases. For compounds with K(aw) values <10(-)(3), K(aw) was the factor determining release rate. When K(aw) was >10(-)(3), mass transport in the gas phase became significant and the Reynolds number played a role. Because release from packaged foods occurs at low Reynolds numbers, whereas most experiments are conducted at medium to high Reynolds numbers, the experimentally defined profile may not reflect the real situation.  相似文献   

Pearl grafting: Tracking the biological origin of nuclei by straightforward immunological methods          下载免费PDF全文

Nelly Schmitt  Frédéric Marin  Jérôme Thomas  Laurent Plasseraud  Marina Demoy‐Schneider 《Aquaculture Research》2018,49(2):692-700

French Polynesia is renowned for the production of Tahitian black pearl. These gems are obtained by grafting a nucleus into the gonad of a receiving oyster together with a graft, i.e. a small section of mantle tissue of a donor oyster. This procedure initiates the formation of a pearl sack around the nucleus, and subsequently, the deposition of concentric layers of nacre. The nucleus plays a key‐role in pearl formation and its characteristics influence markedly the quality of the final product. As it is manufactured from mollusc shells, it contains a small percentage of organics. In the present paper, we used a set of biochemical techniques to characterize and compare the organic matrices from two types of nuclei that are currently used in French Polynesia: that from the freshwater mussel Amblema sp., and that from the pearl oyster Pinctada sp. To this end, we extracted the matrices from nuclei and performed FT‐IR, monodimensional electrophoresis, and enzyme‐linked immuno‐sorbent assay (ELISA). Our data show that the matrix associated with Amblema nuclei has a very different biochemical signature from that of Pinctada nuclei, a fact that may explain the improved tolerance of grafted oysters to nuclei of Pinctada origin. In the absence of complex physical methods of investigation, simple immunological techniques and FT‐IR performed on the extracted organic matrix are extremely reliable and effective for discriminating nuclei from these two sources. We assert that such techniques can be used as a diagnostic test to track unambiguously the biological origin of nuclei to avoid fraud.  相似文献   

The Chemistry of Intercepted Clouds in Northern Arizona during the North American Monsoon Season     

James W. Hutchings  Marin S. Robinson  Heide McIlwraith  Jennifer Triplett Kingston  Pierre Herckes 《Water, air, and soil pollution》2009,199(1-4):191-202

Cloudwater samples have been collected for the first time at a high-elevation site in the US interior Southwest. Cloud samples were collected at the summit of Mt. Elden near Flagstaff, Arizona. The samples were analyzed for pH, ionic composition, trace metals, organic carbon content, and volatile organic compounds. All of the samples showed high pH values (5.12–6.66), which appear to be the result of soil/crustal acid-neutralizing components. Ammonium and nitrate were the dominant ionic species. Organic carbon concentrations ranged from 3 to 18 mg/l. Volatile aromatic compounds (toluene, ethylbenzene, and xylenes) were detected, although they did not contribute significantly to the dissolved organic matter (<1% of dissolved organic carbon). Still, their aqueous-phase concentrations were substantially higher than equilibrium partitioning from the gas phase would suggest. Metal concentrations were high when compared to other cloud studies in remote areas. Overall, with the exception of pH, the cloud chemistry showed marked inter-event variability. The source of the variability was investigated using NOAA HYSPLIT dispersion calculations. Like the cloud composition, the air mass back trajectories differed widely from event to event, and consistently, air masses that passed over highly urbanized areas had higher trace metal, organic, and ion concentrations than more pristine air masses.  相似文献   

Single sequence repeat markers reflect diversity and geographic barriers in Eurasian populations of the conifer pathogen Ceratocystis polonica     

M. Marin  O. Preisig  B. D. Wingfield  T. Kirisits  M. J. Wingfield 《Forest Pathology》2009,39(4):249-265

The blue‐stain fungus and vascular stain pathogen Ceratocystis polonica and its associated bark beetle vectors, particularly Ips typographus and I. typographus japonicus, cause significant losses to several spruce species in Eurasia. Nothing is, however, known about the population genetics of this conifer pathogen. In this study, a set of single sequence repeat (SSR) markers were developed to determine the population structure and genetic diversity of C. polonica in Europe and Japan. ISSR‐PCR primers were used to target SSR‐rich regions and specific primers were designed flanking the SSR regions found in these amplicons. The SSR primers developed for C. polonica were found to be transferable to six other Ceratocystis species from conifers, residing in the Ceratocystis coerulescens complex. Ninety‐eight isolates representing four populations of C. polonica (Austria, Norway, Poland and Japan) were tested using 10 selected polymorphic SSR markers. A high level of gene diversity was found in C. polonica as a whole (H = 0.53). Analysis of G statistics showed a low degree of population structure in Europe and a high level of gene flow between populations (Gst = 0.05, Nm = 8.5). In contrast, the Japanese and the European populations of C. polonica displayed strong genetic separation, which is likely caused by geographic isolation. The low level of population structure of C. polonica in Europe and the differentiation between the European and the Japanese fungal populations mirror previous findings for I. typographus and I. typographus japonicus, the main insect vectors of this fungus. These results support the view that the fungus and the insect have closely co‐evolved together. This study also suggests that movement of C. polonica and its vectors between Europe and Asia pose a threat to forestry on both continents and this should clearly be avoided.  相似文献   

Biological control of chestnut blight in Croatia: an interaction between host sweet chestnut,its pathogen Cryphonectria parasitica and the biocontrol agent Cryphonectria hypovirus 1          下载免费PDF全文

Ljiljana Krstin  Zorana Katanić  Marin Ježić  Igor Poljak  Lucija Nuskern  Ivana Matković  Marilena Idžojtić  Mirna Ćurković‐Perica 《Pest management science》2017,73(3):582-589

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Arbuscular mycorrhizal inoculation of micropropagated persimmon plantlets     

M. Marin  A. Mari  M. Ibarra  L. Garcia-Ferriz 《The Journal of Horticultural Science and Biotechnology》2013,88(5):734-738

Summary

Growth, development and nutrient status of micropropagated persimmon (Diospyros kaki) ‘Rojo Brillante’ in response to inoculation with two species of arbuscular mycorrhizal (AM) fungi were studied under nursery conditions. The species of AM fungi were Glomus intraradices and G. mosseae. Shoot growth depression and low root colonization percentage were observed to G. mosseae inoculation. Shoot and root growth enhancements were observed for plants colonised by G. intraradices. Inoculated plantlets with G. intraradices and high level of controlled-release fertilizer signi®cantly decreased shoot height in relation to treatment with low fertilization level. Furthermore, G. intraradices had unique effects on the mineral status of the persimmon plantlets. N and Ca were significantly increased and decreased, respectively, within the shoot tissue of plants colonised by G. intraradices. Early inoculation with G. intraradices appears to favour growth of micropropagated persimmon plantlets.  相似文献   

Prevalence of Sarcocystis spp. in Argentinean cattle     

Moré G  Abrahamovich P  Jurado S  Bacigalupe D  Marin JC  Rambeaud M  Venturini L  Venturini MC 《Veterinary parasitology》2011,177(1-2):162-165

Sarcocystis cruzi, S. hirsuta and S. hominis are apicomplexan parasites that affect cattle worldwide with variable prevalence. The aim of the present study was to evaluate the prevalence of Sarcocystis spp. in Argentinean cattle comparing microscopic fresh examination and molecular methods. Blood, myocardium and loin samples were collected in five slaughterhouses from a total of 380 bovines. Origin of animals was representative of the major beef cattle production area of Argentina. Samples were analyzed by fresh microscopical examination, transmission electron microscopy (TEM), IFAT and PCR-RFLP. Thin walled sarcocysts corresponding with S. cruzi were found in 99.5% of heart samples. Sarcocysts were detected in 73.1% of loin samples; 71.5% had S. cruzi cysts and 23.1% had thick walled sarcocysts (S. hirsuta or S. hominis). TEM observation revealed the presence of characteristic S. hominis and S. hirsuta cyst walls in 7 and 1 loin samples respectively. Using IFAT, 379/380 animals had titers 25 or higher, showing a full agreement with fresh examination. Amplification products were detected in 35.5% (135/380) of loin samples; however Sarcocystis species could only be determined by RFLP in 29 samples. Agreement between fresh examination and PCR was low (Kappa value=0.262). This is the first report of S. hominis and S. hirsuta in Argentina. Further studies are needed to improve the sensitivity of molecular methods for species identification, especially for differentiation of S. cruzi and S. hirsuta from the zoonotic species S. hominis. The results of the present study and others focusing on sensitivity and specificity of Sarcocystis spp. diagnostic methods should contribute to improve food safety.  相似文献   

Sources of Salmonella contamination during broiler production in Eastern Spain     

Marin C  Balasch S  Vega S  Lainez M 《Preventive veterinary medicine》2011,98(1):39-45

Prevention of Salmonella contamination of poultry products requires detailed knowledge of the main sources associated with its presence in the production system. The aims of this study were to determine the main sources of Salmonella contamination in broiler production during growing, to assess the risk factors for Salmonella contamination at the end of the rearing period and to determine the main serovars involved in broiler production systems in Eastern Spain. A total of 65 different broiler houses from different farms were sampled. Each house was sampled at different times during the rearing period. First, when the previous flock was taken to the slaughterhouse, samples of dust, surfaces and previous flock faeces were collected. After cleaning and disinfection (C&D), samples of dust and surfaces were also taken. On the first day of rearing, samples of water, bedding, farming boots, meconiums, delivery-box liners and feed were collected. During rearing, feed samples were taken directly from the truck and from feeders. On slaughter day, samples of dust, surfaces, water, feed and faeces were also collected. Finally, two days after slaughter, carriers (rodents, flies and beetles) were trapped. All samples collected were analysed according to ISO 6579:2002 (Annex D) and positive samples were serotyped in accordance with Kauffman-White-Le-Minor technique. Our results showed that all different types of samples collected were contaminated with Salmonella (prevalence ranged between 1.5% and 38.6%). The most contaminated samples related with poultry production were: delivery-box liners (32.0%), faeces samples (31.2%), dust samples (25.0%), farming boots (19.7%) and feed from feeders (16.0%). However, the most important risk factors for Salmonella contamination of the flocks at the end of the rearing period were Salmonella status of the house after cleaning and disinfection, Salmonella status of day-old chick flocks and feed from feeders. Twenty-one different serovars were isolated from the samples analysed. The most prevalent were in decreasing order: Salmonella Enteritidis (52.9%), S. Hadar (17.8%), S. Virchow (8.9%) and S. Ohio (5.4%). The study suggested that there are many sources for Salmonella contamination and persistence in broiler production. Hence, the whole production chain needs to be controlled to eradicate the bacteria from primary production.  相似文献