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排序方式: 共有157条查询结果,搜索用时 15 毫秒
41.
Susan M. Tosh Latifeh Ahmadi Lily Yip Mehrnaz Roudsari Peter J. Wood 《Journal of Cereal Science》2012
Depolymerization of mixed linkage cereal β-glucans has been observed during the mixing and fermentation of multigrain breads. To maintain the bioactivity of β-glucans in bread and other foods, control of β-glucanase activity during production is needed. β-Glucanase activity in wheat and dairy ingredients was determined by adding them to β-glucan solutions and following the change in the molecular weight of β-glucan at 50 °C for 60 min. The activities in six wheat and six dairy ingredients ranged from undetectable to a 98% reduction in molecular weight. Calcium propionate, potassium sorbate, and sodium benzoate are salts of organic acids commonly used as food preservatives. Low concentrations of these additives (0.1–1.0%) were found to have an inhibitory effect on the β-glucanases found in wheat flour and whey protein isolate. The depolymerization rate of β-glucan was reduced by up to 76% by the three additives. 相似文献
42.
This study investigates the occurrence and distribution pattern of infectious pancreatic necrosis virus (IPNV) within the pancreas, liver, kidney and spleen of naturally infected cultured rainbow trout, Oncorhynchus mykiss (Walbaum), using immunohistochemistry (IHC). A nested PCR was also employed to confirm the presence of the virus in the pooled tissues of the specimens. All the examined tissues except spleen were immunohistochemically positive for IPNV, but staining intensity and distribution pattern varied. The kidney tubules had the most intense and widespread staining by IHC, indicating a specific tissue tropism at least for this particular serotype. The nucleotide sequence had the greatest identity with the Sp serotype confirming the presence of the nucleic acid of IPNV in the pooled tissues. Based on the present findings, it could be concluded that the absence of lesions consistent with infectious pancreatic necrosis (IPN) disease in the H&E‐stained sections cannot rule out the presence of the IPNV, and the use of an alternative rapid confirmatory method such as IHC with formalin‐fixed, paraffin‐embedded tissue sections is helpful for the final diagnosis of IPN in rainbow trout. 相似文献
43.
Shiga toxin-producing Escherichia coli (STEC) strains are responsible for outbreaks of human intestinal diseases worldwide. Pigeons are distributed in public areas
and are potential reservoirs for pathogenic bacteria. One hundred fifty-four fresh fecal samples were obtained from trapped
pigeons in southeast of Iran and were cultured for isolation of E. coli. The isolates were examined to determine the prevalence of stx1, stx2, and eae genes, antimicrobial resistance, and their phylotypes. The confirmed E. coli isolates (138) belong to four phylogenetic groups: A (54.34%), B1 (34.05%), B2 (3.62%), and D (7.79%). Thirteen (9.42%) isolates
were positive for one of the examined genes. Eight isolates (5.79%) were positive for eae, four (2.89%) for stx2, and one isolate (1.44%) for stx1 gene. Phylotyping assays showed that eight eae-positive isolates fall into three phylogroups; A (three isolates), B1 (three isolates), and D (two isolates), whereas four
stx2-positive isolates belonged to the A (three isolates) and D (one isolate) groups. The stx1-positive isolate belonged to phylogroup A. One hundred six isolates (76.81%) showed resistance to at least one of the selected
antibacterial agents. The maximum resistance rate was against oxytetracycline (73.91%), and the minimum was against flumequine
(2.17%). Twenty different patterns of drug resistance were observed. According to the results, pigeons could be considered
as carriers of STEC strains. However, E. coli isolates of pigeon feces increase the potential of these birds to act as a reservoir of multiple antibiotic resistant bacteria. 相似文献
44.
The Penman-Monteith equation is the most common method for estimating reference crop evapotranspiration (ETo). Using this method reqiures many different meteorological data, yet few stations with adequate meteorological data may exist
in a region. Setting up a station that records the required data for Penman-Monteith equation is expensive. Alternatively,
the Thornthwaite equation is a simpler method for estimating ETo since it is a temperature-based method. In this study, the Thornthwaite equation was spatially calibrated based on the Penman-Monteith
method (as the standard and reference method to compute ETo) for every month of the year, using the meteorologica data of seven synoptic weather stations in Fars province, and seven
synoptic stations outside the Fars province. The Thornthwaite equation using effective temperature that has been introduced
recently in other studies was used (Camargo et al. in Revista Brasileira de Agrometeorologica 7:251–257, 1999). For this purpose a calibration coefficient k must be determined. The results of the spatial and temporal calibration of the new approach using the Thornthwaite equation
showed that for each station different k values should be used monthly. Generally, the k values fluctuated between 0.55 and 1.12, and the mean RMSE for all stations was less than 1 mm day−1, which showed good and reliable agreement between the ETo estimations obtained from the Penman-Monteith and calibrated Thornthwaite equations. Depending on the geographical location
of each station, spatial distribution maps of monthly k values were created for the study area using the inverse distance weighting (IDW) interpolation method. It is therefore possible
to estimate monthly ETo using the appropriate k map and the Thornthwaite equation for different regions of study area instead of using the Penman-Monteith method. This case
study showed that the same analysis might be used for the other parts of the country or any part of the world and would result
in efficient scheduling of water resources for agriculture. 相似文献
45.
Mehrnaz Riasat Asra Ahmadi Niaz Armin Saed-Moucheshi 《Journal of plant nutrition》2018,41(14):1821-1833
This experiment was conducted in a glasshouse at the Agricultural and Natural Resources Research Center of Zarghan, Iran, in 2016. Sixteen wheat genotypes were compared under four salinity levels [control, 50, 100, and 150 mM sodium chloride (NaCl)] in terms of grain yield, chlorophyll (SPAD), flag leaf area, Na+/K+ ratio, catalase, and peroxidase activities in a randomized complete block design with three replications. Overall, results indicated that apparently no single parameter or a specific group of parameters could be suggested as factors of the most responsive element to different salinity stress levels. In other words, the tolerance mechanism of wheat genotypes is a complex response of multiple factors as a network path. Furthermore, different salinity levels led to different responses of wheat genotypes, which were detectable by the results of the mean comparison and analysis of variance. These results also proved the influential effects of the genetic background on salinity response and tolerance of wheat genotypes. In addition, antioxidants acting as defense barriers against reactive oxygen species are very important constituents against salinity, since higher antioxidant activity leads to alleviate the oxidative stress caused by salinity. Higher osmolyte concentration regulating the selective uptake of useful ions can prevent excess accumulation of toxic ions, which contribute to salinity stress damages. A high variation related to the measured traits in this study under both normal and salinity stress conditions was achieved, which could be applied in screening and breeding programs for salinity stress tolerance. Moreover, the responses of different genotypes varied regarding the different traits; SU-0129 as a novel genotype has proved to be the best choice for further breeding research based on the overall traits and, in particular, grain yield and tolerance stress index. 相似文献
46.
Potassium (K) is a major nutrient element that has effects on growth, yield, and quality production of agricultural crops. In the present study, the effects of various K concentrations in a nutrient solution including 150, 235, 300, 400, or 500 mg K L?1 were evaluated on two pepper cultivars; chili pepper (Capsicum annuum Avicolare) and bell pepper (California Wonder) under greenhouse conditions. Hoagland's formula was used for preparation of nutrient solutions. The vegetative growth parameters including plant height, leaf area, SPAD value, and shoot fresh weight were significantly increased by 300 mg L?1 K in both cultivars. The highest yield and fruit quality parameters including fruit length/diameter ratio, fruit dry matter percentage, fruit vitamin C, total soluble solids, and titratable acidity in chili pepper and bell pepper were obtained under application of 300 and 400 mg K L?1 in nutrient solution, respectively. In either cultivar there was increase in leaf K, nitrogen, and zinc concentrations, while in bell pepper calcium was reduced by higher K levels in the nutrient solution. The results indicate that for better growth and quality production of pepper, higher levels of K in nutrient solutions can be beneficial. 相似文献
47.
Alireza Esmaeili Hojat Ahmadi Alireza Abbasi 《Archives of Agronomy and Soil Science》2017,63(2):161-170
Thermography is proposed to be an alternative non-destructive and rapid technique for the study and diagnosing of salt tolerance in plants. In a pot experiment, 30 cultivars of wheat (Triticum aestivum L.) were evaluated in terms of their leaf temperature and shoot growth and their ion distribution responses to NaCl salinity at two concentration levels: the control with electrical conductivity (EC) of 1 dS m?1 and salinity treatment with EC of 16 dS m?1 (150 mM). A completely randomized block design with factorial treatments was employed with three replications. The results indicated that thermography may accurately reflect the physiological status of salt-stressed wheat plants. The salt stress-based increase in leaf temperature of wheat cultivars grown at 150 mM NaCl reached 1.34°C compared to the control. According to the results obtained, it appears that thermography has the capability of discerning differences of salinity tolerance between the cultivars. Three salt-tolerant wheat cultivars, namely Roshan, Kharchia and Sholeh, had higher mean shoot dry matter (0.039 g plant?1) and higher mean ratio of leaf K+/Na+ (14.06) and showed lower increase in the mean leaf temperature (0.37°C) by thermography compared to the control. This was while nine salt-sensitive cultivars, namely Kavir, Ghods, Atrak, Parsi, Bahar, Pishtaz, Falat, Gaspard and Tajan, had lower mean plant dry matter production (0.027 g plant?1), lower mean ratio of K+/Na+ (9.49) and higher mean increases in leaf temperature (1.24°C). 相似文献
48.
This study was carried out to determine the seroprevalence of feline leukemia virus (FeLV), feline immunodeficiency virus (FIV) and Toxoplasma gondii (T. gondii) infection among stray and owned cats in southeastern Iran and to identify the influence of age, sex, lifestyle, health status, and laboratory findings on seropositivity. The overall infection rate for FIV, FeLV, and T. gondii was 19.2%, 14.2%, and 32.1% respectively. Results of the multivariate logistic regression analysis showed that old adults more likely to be seropositive than juveniles for FIV, FeLV, and T. gondii (adjusted odds ratios [ORs], 1.84, 1.56, and 2.57 respectively). Anemic and diseased cats ([ORs], 6.62 and 0.9) were at a greater risk of testing positive for FeLV. Male cats were 4.91 times as likely to have FIV as were female and hyperglobulinemia was significantly more prevalent in FIV-infected cats ([ORs], 3.4). In conclusion, FIV and FeLV seem to be endemic in Iran and retroviral-associated immunosuppression may be a risk factor for active toxoplasmosis in infected cats. 相似文献
49.
Shirin Karimi Abdolreza Mohamadnia Seyed Alireza Nadji Reza Yadegarazari Adnan Khosravi Naghmeh Bahrami Massoud Saidijam 《Iranian Biomedical Journal》2015,19(1):17-22
Introduction: Although extensive research has been conducted on lung cancer markers, a singular clinically applicable marker has not been found yet. The objective of this study was to evaluate the sensitivity and the specificity of carcinoembryonic antigen (CEA) mRNA and lung-specific X protein (LUNX) mRNA biomarkers in peripheral blood to detect lung cancer individually and simultaneously. Methods: Thirty patients affected by lung cancer and 30 healthy individuals were studied in this research. Three vials of cDNA were made from each sample after taking peripheral blood samples and extracting total RNA. Each sample was examined by the real-time RT-PCR technique. The result from each vial was then compared with the sensitivity of overall marker. Results: The CEA mRNA was positive in 24 out of 30 lung cancer patients. Hence, its sensitivity was determined at 80%, differing significantly from that observed in healthy individuals, where 11 positive cases were seen. The overall sensitivity of this marker was significantly associated with positivity in vials 2 and 3 but not in vial 1. The LUNX mRNA was positive in 21 out of 30 patients, indicating 70% sensitivity. This finding significantly differed from that in healthy individuals. The overall sensitivity of this marker was significantly associated with positivity in vials 1 and 3, but not in vial 2. In 93.3% of the patients, at least one positive marker was observed. Conclusion: The mentioned mRNA could be suggested as sensitive and specific markers in peripheral blood for primary diagnosis of lung cancer.Key Words: Lung neoplasms, RNA, Carcinoembryonic antigen, Sensitivity and specificity 相似文献
50.
Shirazi A Shams-Esfandabadi N Ahmadi E Jadidi M Heidari B 《Pakistan journal of biological sciences: PJBS》2008,11(6):938-941
Ovine embryos were produced by maturation, fertilization and in vitro culture (IVM/IVF/IVC) of oocytes collected from slaughtered prepubertal ewes. At 24 h post IVM, oocytes were fertilized with fresh semen collected from Lori-Bakhtiari breed at a concentration of 1.0 x l0(6) sperm mL(-1). The presumptive ova/embryos were transferred into the embryo culture medium at 22-24 h post IVF. Following 4 to 7 day in culture, embryos (at morula and blastocyst stage, respectively) were transferred surgically to the uterine horn of synchronized recipients. Pregnancy was diagnosed at day 30 by hormonal assay and at days 55 and 140 of gestation by ultrasonography and pregnancies were allowed to go to term. A total of nine ewes received 27 embryos (3 embryos/ewe). Five ewes received 15 embryos at morula stage and four ewes received 12 embryos at blastocyst stage. From those received morula stage embryos one was pregnant on day 30 (20%), though no pregnancy was diagnosed on each of days 55 and 140. While from those received blastocyst stage embryos, three ewes were pregnant on day 30 (75%) and two ewes (50%) remained pregnant on each of days 55 and 140. In conclusion, day 4 IVM-IVF morula stage embryos had a lower survival rate than did day 7 IVM-IVF blastocysts embryos, following transfer to the synchronized recipient ewes. 相似文献