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Laura Righetti Roberta Paris Claudio Ratti Matteo Calassanzio Chiara Onofri Davide Calzolari Wulf Menzel Dennis Knierim Gianmaria Magagnini Daniela Pacifico Gianpaolo Grassi 《European journal of plant pathology / European Foundation for Plant Pathology》2018,150(3):575-588
Interveinal chlorosis and leaf margin wrinkling are widespread symptoms of Cannabis sativa. They are traditionally attributed to the so-called hemp streak virus (HSV), but its existence has not been demonstrated yet. To our knowledge, no molecular investigation has so far been performed in order to identify the causal agent of this symptomatology, we therefore decided to use traditional and molecular virology techniques to better characterize symptoms and pursue the etiological agent. No pathogenic virus was found by using targeted PCR reactions and by RNA sequencing, whereas we were able to detect the Cannabis cryptic virus (CanCV) with both techniques. We, therefore, developed an RT-qPCR assay based on a CanCV-specific TaqMan probe and applied it to a wide range of symptomatic and symptomless plants, using a two-step (for quantification), or a one-step (for fast detection) protocol. Both symptoms and the virus were only shown to be transmitted vertically and did not pass via mechanical inoculation or grafting, though we could not find any cause-effect correlation between them. In fact, the virus was found in all the tested hemp samples, and its abundance varied greatly between different accessions and individuals, independently from the presence and severity of symptoms. The suggestion that hemp streak is caused by a virus is therefore questioned. Some abiotic stresses seem to play a role in triggering the symptoms but this aspect needs further investigation. For breeding purposes, a selection of parental plants based on the absence of symptoms proved to be efficient in containment of the disease. 相似文献
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Journal of Plant Diseases and Protection - In 2016, symptoms of stem canker with branches dieback were detected in several Cannabis sativa L. crops, located in the northeast part of Italy (Rovigo... 相似文献
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The appropriateness of three official fisheries management reference points used in the north‐east Atlantic was investigated: (i) the smallest stock size that is still within safe biological limits (SSBpa), (ii) the maximum sustainable rate of exploitation (Fmsy) and (iii) the age at first capture. As for (i), in 45% of the examined stocks, the official value for SSBpa was below the consensus estimates determined from three different methods. With respect to (ii), the official estimates of Fmsy exceeded natural mortality M in 76% of the stocks, although M is widely regarded as natural upper limit for Fmsy. And regarding (iii), the age at first capture was below the age at maturity in 74% of the stocks. No official estimates of the stock size (SSBmsy) that can produce the maximum sustainable yield (MSY) are available for the north‐east Atlantic. An analysis of stocks from other areas confirmed that twice SSBpa provides a reasonable preliminary estimate. Comparing stock sizes in 2013 against this proxy showed that 88% were below the level that can produce MSY. Also, 52% of the stocks were outside of safe biological limits, and 12% were severely depleted. Fishing mortality in 2013 exceeded natural mortality in 73% of the stocks, including those that were severely depleted. These results point to the urgent need to re‐assess fisheries reference points in the north‐east Atlantic and to implement the regulations of the new European Common Fisheries Policy regarding sustainable fishing pressure, healthy stock sizes and adult age/size at first capture. 相似文献
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M Drost J D Savio C M Barros L Badinga W W Thatcher 《Journal of the American Veterinary Medical Association》1992,200(3):337-339
For the purpose of collecting active ovarian structures for cell culture, unilateral ovariectomy (n = 34 ovaries) was performed per vagina on 17 dairy cows having normal estrous cycles, bilateral ovariectomy was performed on 9 (n = 18 ovaries) dairy cows, and corpora lutea (n = 13) were removed from 11 beef cows having normal estrous cycles. None of the cows was clinically ill after the operation. Nine of 37 cows developed adhesions of both uterine horns and the body of the uterus. Three instruments were used to perform colpotomy. The described surgical technique for removal of the ovaries or corpora lutea is practical and inexpensive, and has low morbidity associated with it. 相似文献
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Specific anti-Toxoplasma gondii antibodies were analyzed by latex agglutination during the 5 months of pregnancy in the serum of sheep from two flocks in the Uruguayan north-west: one flock (79 sheep) kept under an intensive management system and the other (494 sheep) kept under an extensive management system. Titers obtained using the latex test correlated with those obtained by indirect immunofluorescence. Pregnancy was confirmed by laparoscopy in all sheep from the smaller flock and by determination of serum progesterone levels in the seroconverted sheep from the larger flock. The percentage of sheep originally exhibiting significant serum levels of anti-T. gondii anti-bodies (13.9% in the smaller flock and 28.5% in the larger one) as well as the observed levels of seroconversion (22.8% and 7.7%, respectively), indicated a high prevalence of this infection in the north-west of Uruguay. In addition, birth rates of seroconverted sheep in the larger flock were significantly different from those of non-seroconverted animals. These results, although preliminary, suggest that Toxoplasma infection would produce considerable economic losses in extensive ovine production in Uruguay. 相似文献
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Lucca A. C. Savio Gustavo M. Dias Kelen L. Leite Silvia N. Godoi Apoena C. Figueiroa Geraldo F. O. Neto Edineia C. Correa Carlo L. B. Francini Gustavo Shintate Marcelo V. Kitahara 《水产资源保护:海洋与淡水生态系统》2021,31(10):2830-2841
- The introduction of exotic species is one of the major causes for biodiversity loss in marine environments. Introduced species can change habitat complexity, impacting local communities and altering ecosystem functioning.
- Since the 1980s, the scleractinian species Tubastraea coccinea and Tubastraea. tagusensis (commonly known as sun corals) have been spreading in the south-western Atlantic, posing a major threat to local biodiversity and marine ecosystems. Nowadays, these species are reported from more than 3,500 km along the Brazilian coast and on at least 21 oil and gas offshore platforms.
- Considering the great environmental pressure resulting from sun coral invasion, this study verified the effectiveness of manual removal of Tubastraea spp. along a rocky shore in Alcatrazes Wildlife Refuge, one of the most pristine marine regions in Brazil.
- Results indicate that removal is indeed effective as a control technique; however, as invaders have high regeneration capabilities and recruitment rates, successive management efforts are essential. In order for management to be effective against Tubastraea's year-round release of clonal larvae, results suggest invaded areas should receive at least two management actions per year.
- Successive management efforts, in addition to the development of new techniques and prevention of new invasions should be priorities for mitigating sun coral impacts.
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Rainer Froese Nazli Demirel Gianpaolo Coro Kristin M Kleisner Henning Winker 《Fish and Fisheries》2017,18(3):506-526
This study presents a Monte Carlo method (CMSY) for estimating fisheries reference points from catch, resilience and qualitative stock status information on data‐limited stocks. It also presents a Bayesian state‐space implementation of the Schaefer production model (BSM), fitted to catch and biomass or catch‐per‐unit‐of‐effort (CPUE) data. Special emphasis was given to derive informative priors for productivity, unexploited stock size, catchability and biomass from population dynamics theory. Both models gave good predictions of the maximum intrinsic rate of population increase r, unexploited stock size k and maximum sustainable yield MSY when validated against simulated data with known parameter values. CMSY provided, in addition, reasonable predictions of relative biomass and exploitation rate. Both models were evaluated against 128 real stocks, where estimates of biomass were available from full stock assessments. BSM estimates of r, k and MSY were used as benchmarks for the respective CMSY estimates and were not significantly different in 76% of the stocks. A similar test against 28 data‐limited stocks, where CPUE instead of biomass was available, showed that BSM and CMSY estimates of r, k and MSY were not significantly different in 89% of the stocks. Both CMSY and BSM combine the production model with a simple stock–recruitment model, accounting for reduced recruitment at severely depleted stock sizes. 相似文献
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Florencia Cora Jofré Micaela Perez Marianela Savio 《Communications in Soil Science and Plant Analysis》2020,51(16):2205-2214
ABSTRACT Soil monitoring and research often requires a comparison of laboratory data generated by diverse instruments and in different laboratories to demonstrate the reliability and accuracy of the results. The outcomes of this work highlight a performance comparison among different analytical methods for the determination of calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K), in soil. Five soil samples were used for analytical methods comparison, corresponding to an argentine agricultural soil interlaboratory, and four soil samples from the Pampa region of Argentina were used for analytical application of the instrumental methods. The results obtained with flame atomic absorption and emission spectrometry (FAAS-FAES) and microwave-induced plasma optical emission spectrometry (MIP OES) were compared to those obtained by conventional analytical methods as complexometric titration and flame photometry. As there were no significant differences between classical methods with instrumental ones, FAAS-FAES and MIP OES were validated following criteria based on international guidelines. Accuracy, precision, linearity, limits of detection and quantification, sensitivity, analytical sensitivity, and working range were evaluated. The results established the satisfactory performance of FAAS-FAES and MIP OES for exchangeable cations. MIP OES is an efficient alternative to FAAS-FAES, with wide linear dynamic range, which is advantageous concerning to the concentrations in which these exchangeable cations are found in soils, avoiding sample dilutions. The most remarkable advantage of MIP OES is the low running costs as it does not use flammable and toxic gases. Due to its benefits MIP OES could be recommended as the main analytical method for exchangeable cations determination. 相似文献