Relationship between greenhouse gas emissions and changes in soil gas diffusivity in a field experiment with biochar and lime     

Thomas Keller  Roman Hüppi  Jens Leifeld 《植物养料与土壤学杂志》2019,182(4):667-675

Reducing greenhouse gas emissions from arable soil while maintaining productivity is a major challenge for agriculture. Biochar is known to reduce N₂O emissions from soil, but the underlying mechanisms are unclear. This study examined the impact of green waste biochar (20 Mg ha^?1) and lime (CaCO₃; 2 Mg ha^?1) application on soil gas transport properties and related changes in these to soil N₂O and CO₂ emissions measured using automated chambers in a field experiment cropped with maize. In situ soil water content monitoring was combined with laboratory measurements of relative soil gas diffusion coefficient (D_p/D₀) at different matric potentials, to determine changes in D_p/D₀ over time. Cumulative N₂O emissions were similar in the control and lime treatment, but much lower in the biochar treatment. Cumulative CO₂ emissions decreased in the order: lime treatment > biochar treatment > control soil. When N₂O emissions were not driven by excess N supply shortly after fertilisation, they were associated with D_p/D₀ changes, whereby decreases in D_p/D₀ corresponded to N₂O emissions peaks. No distinct pattern was observed between CO₂ emissions and D_p/D₀. Cumulative N₂O emissions were positively related to number of days with D_p/D₀ < 0.02, a critical limit for soil aeration. These results indicate that improved soil gas diffusivity, and hence improved soil aeration, may explain the effect of biochar in reducing N₂O emissions. They also suggest that knowledge of D_p/D₀ changes may be key to explaining N₂O emissions.  相似文献   

Defining the immune response to Ehrlichia species using murine models     

Stephen K. Chapes  Roman R. Ganta 《Veterinary parasitology》2008

Pathogenic bacteria belonging to the family Anaplasmataceae include species of the genera Ehrlichia and Anaplasma. Ehrlichia chaffeensis, first known as the causative agent of human monocytic ehrlichiosis, also infects several vertebrate hosts including white-tailed deer, dogs, coyotes and goats. E. chaffeensis is transmitted from the bite of an infected hard tick, such as Amblyomma americanum. E. chaffeensis and other tick-transmitted pathogens have adapted to both the tick and vertebrate host cell environments. Although E. chaffeensis persists in both vertebrate and tick hosts for long periods of time, little is known about that process. Immunological studies will be valuable in assessing how the pathogen persists in nature in both vertebrate and invertebrate hosts. Understanding the host immune response to the pathogen originating from dual host backgrounds is also important to develop effective methods of diagnosis, control and treatment. In this paper, we provide our perspective of the current understanding of the immune response against E. chaffeensis in relation to other related Anaplasmataceae pathogens.  相似文献   

Isolation of a novel viral agent associated with porcine reproductive and neurological syndrome and reproduction of the disease     

Pogranichniy RM  Schwartz KJ  Yoon KJ 《Veterinary microbiology》2008,131(1-2):35-46

Disease outbreaks characterized by reproductive failure and/or neurologic disorders, which are commonly referred as "Porcine Reproductive and Neurologic Syndrome (PRNS)", were observed in many swine farms in Iowa and other states. Although an infectious cause was suspected to account for the disease, no conclusive diagnosis had been reached with respect to conventional infectious agents. Extensive laboratory diagnostic investigation on suspect cases repeatedly resulted in the isolation of a cytopathic enveloped virus of 50-60nm in size from nervous and second lymphoid tissues and sera and, to reflect its unknown identity, named "Virus X". The presence of virus particle with morphological characteristics similar to Virus X in tissues from affected animals was also observed on thin-section positive-staining electron microscopy. Isolates of Virus X were not readily recognized by antibodies raised against any known viruses pathogenic to swine but by antisera collected from animals surviving clinical episode, indicating that Virus X is likely a previously unrecognized agent. Pregnant sows experimentally inoculated with Virus X (ISUYP604671) or homogenate (filtrate) of tissues from a clinically affected animal developed clinical signs and pathological changes similar to field observations including the loss of pregnancy. Furthermore, caesarian-derived, colostrum-deprived young pigs developed mild encephalomyelitis lesions in brains after experimental inoculation with the virus or the tissue homogenate although clinical neurologic signs were not observed. More importantly, Virus X was re-isolated from all inoculated animals while control pigs remained negative for the virus during the study. Collectively, Virus X is a novel viral agent responsible for PRNS and remains to be further characterized for taxonomical identity.  相似文献   

Detection of virulent feline herpesvirus-1 in the corneas of clinically normal cats     

Stiles J  Pogranichniy R 《Journal of Feline Medicine and Surgery》2008,10(2):154-159

To evaluate the clinically normal feline cornea for the presence of virulent feline herpesvirus-1 (FHV-1), corneas from 31 cats (25 with normal eyes and six with active disease or corneal scarring) euthanased at a shelter were collected. Corneas from two specific pathogen-free cats were included as negative controls. Virus isolation (VI), fluorescent antibody (FA) staining and real-time polymerase chain reaction (rt-PCR) were performed on all samples. The presence or absence of dexamethasone in the media was evaluated for its effect on VI. VI was positive for FHV-1 in six corneas from five cats, all with clinically normal eyes. One cornea was positive for feline calicivirus (FCV) in addition to FHV-1, but only in media that included dexamethasone. Eight corneas were positive on rt-PCR for FHV-1, all from cats with clinically normal eyes. All positive VI samples were confirmed with FA staining. VI and rt-PCR were negative for FHV-1 and FCV in cats with active disease or corneal scarring. Data from this study indicate that virulent FHV-1 and FCV can be present in feline corneas that are clinically normal. Dexamethasone may enhance viral spread through a cell receptor mechanism.  相似文献   

Taxonomy,distribution, and contemporary exposure of terrestrial mammals to floods and human pressure across different areas for biodiversity conservation in China     

Roman SHARNUUD  Eric I. AMECA 《Integrative zoology》2024,19(3):458-467

A significant research focus is placed on identifying animal species and areas at future risk to human-induced alterations of the environment and long-term changes in climatic conditions. Yet, the extent to which exposure to extreme climatic events and intense human pressure can increase the risk of harmful impacts on species remains poorly investigated. Focusing on terrestrial mammals in China, one of the world's megadiverse countries, we investigated patterns of contemporary exposure to floods and human pressures and determined their taxonomic representation and distribution across three major area-based conservation schemes, namely, national nature reserves (NNRs), priority areas for biodiversity conservation (PABCs), and key biodiversity areas (KBAs). Among the 440 species assessed with moderate or high exposure to floods, 327 (∼75%) also qualified as moderate or high in exposure to intense human pressure. These species mainly belong to the orders Chiroptera, Eulipotyphla, and Rodentia. Likewise, there were 305, 311, and 311 species with moderate or high exposure to flood and intense human pressure represented across NNRs, PABCs, and KBAs, respectively. Our findings support the prioritization of KBAs for expansion of site-based protection efforts such as NNRs in China, considering threats to species from exposure to adverse effects from both extreme climate and human pressure.  相似文献   

The effect of timing of extended photoperiod on growth and maturity of brook trout (Salvelinus fontinalis)     

Katsiaryna Lundova  Jan Matousek  Marketa Prokesova  Roman Sebesta  Tomas Policar  Vlastimil Stejskal 《Aquaculture Research》2019,50(6):1697-1704

The influence of timing of extended photoperiods on growth and maturity of brook trout was investigated in a 112‐day experiment. The fish with mean initial weight of ~192 g were reared under four light regimes: one control group with natural ambient photoperiod and three groups exposed to an 18L:6D regime initiated at days 1, 23 or 46 of the growth trial. Light‐emitting diodes, with intensity of 250–1000 lux, depending on the distance from the light source, were used for extending light periods. There was a positive effect of prolonged day length on fish growth (p < 0.05), and a delay in gonad development and sexual maturity. Significantly higher numbers of sexually mature fish were found among controls groups, regardless of sex. Survival rate was not affected by light regime. This study demonstrated that the short‐term expansion of the photo period delayed maturation and increased the growth rate of brook trout.  相似文献   

Effect of temperature on growth and survival of maraena whitefish Coregonus maraena (Bloch 1779) larvae in controlled conditions          下载免费PDF全文

Roman Sebesta  Dariusz Kucharczyk  Joanna Nowosad  Mateusz Sikora  Vlastimil Stejskal 《Aquaculture Research》2018,49(9):3151-3157

This 28‐day study investigated the effect of three rearing temperatures, 11, 15 and 19°C, on survival and growth of maraena whitefish fry in a recirculating aquaculture system. Three groups of larvae in three repetitions were reared in recirculating system. Each group comprised 200 larvae. Feeding level was fixed at 500–700 Artemia sp. metanauplii per fish per day. Larvae were fed fresh live brine shrimp at 10 ml/tank every 3 hr. Significantly higher body weight (p = 0.00), total length (p = 0.00), larval yield (p = 0.00) and condition factor (p = 0.00) were obtained at 19°C compared to 15 and 11°C, as well as at 15°C compared to 11°C. Significantly higher survival (p = 0.00) was observed in larvae reared at 11 and 15°C compare to 19°C and no significant differences were observed between 11°C compared to 15°C. No significant differences in size heterogeneity among treatments were found (p = 0.46). In larviculture, the optimal assessed temperature for growth of maraena whitefish was 19°C, with highest survival observed at 11°C, at the end of this 28 days trial. The findings in this study apply to the particular study location and may not be applicable more broadly.  相似文献   

Report on the 43rd Annual Meeting of the DPG-Working Group Nematology     

Daub  Matthias  Hakl  Ulrike  Molendijk  Leendert PG  Schomaker  Corrie  Been  Thomas H  van Beers  Thea G  Jivishova  Sevda  Jivishov  Emil  Keusgen  Michael  Bluemel  Roman  Fischer  Daniel  Grundler  Florian MW  Reuther  Marie  Cappel  Sabrina  Bauer  Harald  Lang  Christian  Watrin  Cliff  den Nijs  Loes JMF  Van Bruggen  Anne-Sophie  Karssen  Gerrit  Kiewnick  Sebastian  Büchler  Urs  Roth  Irma  Frey  Jürg 《植物病害和植物保护杂志》2015,122(4):189-193

Journal of Plant Diseases and Protection -  相似文献   

Novel technique for definite blastomere inhibition and distribution of maternal RNA in sterlet Acipenser ruthenus embryo     

Shah  Mujahid Ali  Saito  Taiju  Šindelka  Radek  Iegorova  Viktoriia  Rodina  Marek  Baloch  Abdul Rasheed  Franěk  Roman  Tichopád  Tomáš  Pšenička  Martin 《Fisheries Science》2021,87(1):71-83

Fisheries Science - The cleavage pattern of a vertebrate’s embryo is either holoblastic (complete) or meroblastic (partial). Sturgeon and other basal bony fishes represent a transition of the...  相似文献   

波兰花卉种子产业     

张景峰  张启翔  潘会堂 《种子》2009,28(3)

由于花卉种子生产的赢利小于农作物和蔬菜,波兰种子生产部门对其不够重视.但是波兰依然是欧洲重要观赏植物生产国之一,至少有50个园艺公司在生产花卉种子和观赏植物.以下主要介绍波兰花卉种子产业的历史,现状,市场和新品种审定.  相似文献