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21.
Anne Hoffmann Sabine Milde Christine Desel Anja Hümpel Hartmut Kaiser Enno Hammes Mirva Piippo Arto Soitamo Eva‐Mari Aro Jóska Gerendás Burkhard Sattelmacher Ulf‐Peter Hansen 《植物养料与土壤学杂志》2007,170(1):87-97
Ammonium (NH ) nutrition causes retardation of growth in many plant species. In Arabidopsis grown with NH as the sole N source, growth retardation occurs already at early stages before photosynthesis has come to its full power. In order to describe the peculiarities of these retarded plants, they were compared with nitrate (NO )‐grown plants of the same age of 15 d. Photosynthetic activity as measured by CO2 uptake per unit chlorophyll is half as high in NH ‐grown seedlings as in NO ‐grown ones. This finding is confirmed by the analysis of chlorophyll fluorescence. Chloroplasts of NO ‐grown, but not of NH ‐grown, seedlings show starch deposits after 5 h of illumination with 40 μmol m–2 s–1. Gene‐expression analysis based on cDNA microarray and on Northern blots provide a clue about the biochemical background. After the first 2 weeks of growth, it seems that NO ‐grown seedlings subsist mainly on normal photosynthesis, whereas NH ‐grown seedlings still use lipids from the seeds stored in oleosomes. Corresponding to this observation, the mRNAs for enzymes of β‐oxidation are more strongly expressed in NH ‐grown seedlings. Different carbohydrate sources for sucrose synthesis are indicated by different gene expression. Higher gene expression of fructose bisphosphate aldolase (cytosolic isoform) in NO ‐grown seedlings indicates the dependence on photosynthesis, whereas a higher gene expression of PEP carboxykinase in NH ‐grown seedlings points to a prominent role of β‐oxidation of storage lipids still present. 相似文献
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Ruan E. F. Abreu Thaís C Magalhães Renilde C Souza Samira TL Oliveira Adriana MG Ibelli Fábio N Demarqui João JS Gouveia Mateus M Costa Gisele V Gouveia 《Aquaculture International》2018,26(2):495-507
Aeromonas hydrophila are known for being opportunistic pathogens, harboring various virulence factors and triggering lesions and death in fish. The disease caused by bacteria can make fish inappropriate for human consumption, besides representing a risk to public health. The pathogenesis can be influenced by environmental variables, affecting fish productivity and mortality. The present study aimed to determine whether A. hydrophila harbor the virulence genes aerolysin, hydrolipase, elastase, lipase, cytotonic enterotoxin (ast), lateral flagellum (laf), and polar flagellum (fla) and to evaluate the influence of environmental variables on in vitro growth, in vivo virulence and expression of some of these genes. Polymerase chain reaction (PCR)-based screening for the presence of these virulence genes was performed on 35 isolates. Six isolates containing different profiles of virulence genes were tested for in vitro growth under different conditions of pH, temperature, and ammonia and for in vivo virulence under these same environmental conditions. RT-qPCR was used to quantify the expression of aerolysin, lipase, and fla genes. All the tested environmental factors influenced the growth of A. hydrophila, while pH and ammonia concentrations influenced the bacterial virulence. The expression of the fla gene increased when bacteria were grown in higher ammonia concentration. The mortality established by Aeromonas is influenced by several environmental factors pinpointing the importance of its control in fish farming to avoid higher economic loses associated to bacterial disease outbreaks. 相似文献
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Thirty Atlantic salmon, Salmo salar L., with low corporal condition relative to other fish present in the culture system, were sampled from a freshwater recirculation pisciculture located in Chile. The most characteristic signs and lesions were cachexia and presence of multiple greyish‐white granulomas within internal organs. The external and internal lesions, along with the microscopic, histologic and biochemical findings, were consistent with mycobacteriosis. The identification of Mycobacterium salmoniphilum as the causal agent of the lesions was possible through the use of molecular analyses. This study represents the first report of Mycobacterium salmoniphilum in a freshwater recirculation system and the first case of fish mycobacteriosis described in Chile. 相似文献
24.
Hirvonen T Tapanainen H Valsta L Hannila ML Aro A Pietinen P 《Public health nutrition》2006,9(6):792-797
OBJECTIVE: To examine the efficacy and safety of foods fortified with calcium in the adult population in Finland. DESIGN: A simulation study based on the FINDIET 2002 Survey, which estimated habitual food consumption, dietary supplement use and nutrient intakes using 48-hour recall and two 3-day food records, and an Internet survey of the consumption of fortified foods and dietary supplements. SETTING/PARTICIPANTS: Participants of FINDIET 2002 were 25-64 years old from five areas (n = 2007). Participants of the Internet-based survey (n = 1537) were over 15 years of age from all over the country. RESULTS: If all potentially fortifiable foods were to be fortified with calcium, the proportion of participants with calcium intake below the recommended level (< 800 mg day(-1)) would decrease from 20.3% to 3.0% in men and from 27.8% to 5.6% in women compared with the situation where no foods were fortified. At the same time, the proportion of participants with calcium intake above the tolerable upper intake level (UL, > 2500 mg day(-1)) would increase from 0.6% to 12.7% in men and from 0.1% to 3.8% in women. However, in a probability-based model (11% of all fortifiable foods to be fortified with calcium) the proportion of participants with calcium intake below the recommended level would be 15.7% in men and 23.2% in women. The proportion with intake above the UL in this model would be 1.2% in men and 0.7% in women. CONCLUSIONS: Food fortification would be a relatively effective and safe way to increase the calcium intake of the Finnish adult population. 相似文献
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Matthew D. Aro Xiping Wang Dwight E. McDonald Marshall Begel 《Wood material science & engineering》2017,12(4):228-235
Laminated strand lumber (LSL) and laminated veneer lumber (LVL) were thermally modified as a post-treatment at 140°C, 150°C, 160°C, 170°C, and 180°C. The tension modulus of elasticity (MOE) of LSL was not significantly impacted by the treatments, with the 180°C treatment group exhibiting the highest tension MOE (11.8?GPa). The LVL also experienced minimal impacts, with the 150°C treatment group having the highest tension MOE (19.4?GPa) and the 160°C treatment group exhibiting the lowest (17.1?GPa). The maximum tensile strength (MTS) of the LSL and LVL significantly decreased with increasing temperatures, with the control and 180°C treatment groups experiencing the highest and lowest MTS, respectively. The lowest MTS for LSL was 10.8?MPa (180°C treatment), which was 70% lower than the controls. The lowest MTS of the LVL was 24.4?MPa (also at the 180°C treatment), which was a 49% decrease compared to the controls. These results suggest that thermal-modification post-treatments minimally impact tension MOE, but can significantly reduce MTS at higher treatment temperatures. Combined with previous work improving the moisture properties and equilibrium moisture content of thermally modified LSL and LVL, it may be possible to optimize the treatment technique(s) to yield products with desirable properties. 相似文献
27.
KA Carroll ML Wallace TL Hill JW Bartges JL Ruby AT Mulder II JI Helmick 《Australian veterinary journal》2020,98(1-2):11-16
A 6-year-old, male neutered mixed breed dog was presented emergently with a three-week history of hyporexia, vomiting, diarrhoea and weight loss. Upon examination, the patient was dull, had generalised muscle atrophy, moderate abdominal pain and a mild amount of peritoneal effusion. A fluid-filled, distended, corrugated small bowel with marked gastroparesis and moderate peritoneal effusion was noted on abdominal ultrasonography. Endoscopy revealed hyperaemic and friable mucosa and a subjectively narrowed pylorus. Emergency exploratory celiotomy was performed due to worsening patient condition and revealed thick, diffuse, fibrous adhesions of the abdominal cavity. Based on these findings, sclerosing encapsulating peritonitis (SEP) was suspected. A large mass of omentum adjacent to the greater curvature of the stomach had caused a pyloric outflow obstruction. Adhesiolysis was attempted but was unsuccessful due to the friability of the small intestines. The dog was humanely euthanased under anaesthesia. A diagnosis of SEP was confirmed via necropsy. No underlying cause was identified. This is the first known case of a pyloric outflow obstruction secondary to SEP in a dog. Although rare, this condition should be considered as a differential for dogs with signs of a pyloric outflow obstruction with concurrent ascites and abdominal pain, hyporexia, vomiting and diarrhoea. 相似文献
28.
F Hill PB Stark RT Stebbins ER Anderson HM Antia TM Brown TL Duvall DA Haber JW Harvey DH Hathaway R Howe RP Hubbard HP Jones JR Kennedy SG Korzennik AG Kosovichev JW Leibacher KG Libbrecht JA Pintar EJ Rhodes J Schou MJ Thompson S Tomczyk CG Toner R Toussaint WE Williams 《Science (New York, N.Y.)》1996,272(5266):1292-1296
The Global Oscillation Network Group (GONG) project estimates the frequencies, amplitudes, and linewidths of more than 250,000 acoustic resonances of the sun from data sets lasting 36 days. The frequency resolution of a single data set is 0.321 microhertz. For frequencies averaged over the azimuthal order m, the median formal error is 0.044 microhertz, and the associated median fractional error is 1.6 x 10(-5). For a 3-year data set, the fractional error is expected to be 3 x 10(-6). The GONG m-averaged frequency measurements differ from other helioseismic data sets by 0.03 to 0.08 microhertz. The differences arise from a combination of systematic errors, random errors, and possible changes in solar structure. 相似文献