Optimizing inoculum production methods for infesting soil with Phytophthora species

Plant Disease ◽  
2021 ◽  
Author(s):  
E. Anne Davis ◽  
Jerry E. Weiland ◽  
Carolyn F. Scagel

Inoculum production is an important part of conducting research with soilborne Phytophthora species. One common method is to incubate Phytophthora cultures in nutrient-amended vermiculite. However, inoculum levels often vary among batches of inoculum even when production methods remain the same, and incubation typically takes ≥ 6 weeks, increasing risks for delayed experiments if the resulting inoculum level is too low. A more reliable and rapid method is needed for future studies. Experiments were conducted to: (1) determine inoculum levels of P. cinnamomi and P. plurivora after incubation in V8 juice-amended vermiculite (standard method); (2) evaluate how inoculum viability was affected by air drying; (3) develop a modified method that takes less time to produce a vermiculite-based inoculum; and (4) evaluate the effect of storage on inoculum viability. Results showed that the standard method produced inoculum levels from 716 to 1808 colony forming units/g and that drying to < 78% moisture content significantly reduced viability. The modified method used 2-week-old Phytophthora cultures to infest vermiculite at 80% moisture content and produced inoculum levels from 214 to 525 CFU/g. Storage for >1 day generally reduced inoculum viability. Although inoculum levels from the modified method were lower than the standard method, inoculum levels for each isolate were more consistent between trials and the modified method was 6 to 8 weeks faster. Production with the modified method can also be easily scaled up by infesting a greater volume of vermiculite with additional cultures of Phytophthora. These results are important because they help explain variability in soilborne Phytophthora inoculum production and storage, and provide a new method for producing inoculum more quickly.

Author(s):  
O. A. Zadorozhna ◽  
T. P. Shyianova ◽  
M.Yu. Skorokhodov

Seed longevity of 76 spring barley gene pool samples (Hordeum vulgare L. subsp. distichon, convar. distichon: 56 nutans Schubl., two deficience (Steud.) Koern., two erectum Rode ex Shuebl., two medicum Koern.; convar. nudum (L.) A.Trof.: one nudum L. та subsp. vulgare: convar. vulgare: nine pallidum Ser., three rikotense Regel.; convar. coeleste (L.) A.Trof.: one coeleste (L.) A.Trof.) from 26 countries, 11 years and four places of reproduction was analyzed. Seeds with 5–8% moisture content were stored in chamber with unregulated and 4oC temperature. The possibility of seed storage under these conditions for at least 10 years without significant changes in germination has been established. The importance of meteorological conditions in the formation and ripening of seeds for their longevity is confirmed. The relationship between the decrease of barley seeds longevity and storage conditions, amount of rainfall, temperature regime during the growing season of plants is discussed.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hailin Zhang ◽  
João Antonangelo ◽  
Chad Penn

AbstractPortable X-ray fluorescence (pXRF) spectrometer allows fast in-situ elemental determination without wet digestion for soils or geological materials, but the use of XRF on wet materials is not well documented. Our objective was to develop a rapid field method using pXRF to measure metals in the residues from horizontal directional drilling (HDD) operations so that proper disposal decisions can be made in-situ. To establish the procedure, we spiked soil samples with 4 concentrations of Cr, Ni, Cu, Zn, As, Cd, and Pb up to 1000 mg kg−1, and then the metal concentrations were determined by wet chemical method after drying and acid digestion (standard method), and by pXRF, also at laboratory conditions, after drying and at two different moisture conditions. The measurements by pXRF and standard method after drying and after removal of excess water (AREW) were highly correlated with slopes ranging from 0.83 ± 0.01 to 1.08 ± 0.01 (P < 0.001) for all metals. The relationship was better AREW than the saturated paste without removal of excess water and the moisture content affected only the accuracy of As, Cd, and Pb. The procedure established was successfully used for HDD residues collected from 26 states of US with moisture content ranging from 14 to 83% AREW. The pXRF was proven to be a reliable tool for fast detection of common metals in dried soils and HDD residues, and samples containing < 30% moisture content without needing to correct for moisture. If the moisture is > 30%, excess water in samples need to be removed with a commercially available filter press to achieve high accuracy. The developed procedures reduce time of metal detection from days to about an hour which allows drilling operators to make quick decisions on soil or HDD disposal.


Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 32
Author(s):  
Waleed H. Hassoon ◽  
Dariusz Dziki ◽  
Antoni Miś ◽  
Beata Biernacka

The objective of this study was to determine the grinding characteristics of wheat with a low moisture content. Two kinds of wheat—soft spelt wheat and hard Khorasan wheat—were dried at 45 °C to reduce the moisture content from 12% to 5% (wet basis). Air drying at 45 °C and storage in a climatic chamber (45 °C, 10% relative humidity) were the methods used for grain dehydration. The grinding process was carried out using a knife mill. After grinding, the particle size distribution, average particle size and grinding energy indices were determined. In addition, the dough mixing properties of wholemeal flour dough were studied using a farinograph. It was observed that decreasing the moisture content in wheat grains from 12% to 5% made the grinding process more effective. As a result, the average particle size of the ground material was decreased. This effect was found in both soft and hard wheat. Importantly, lowering the grain moisture led to about a twofold decrease in the required grinding energy. Moreover, the flour obtained from the dried grains showed higher water absorption and higher dough stability during mixing. However, the method of grain dehydration had little or no effect on the results of the grinding process or dough properties.


2009 ◽  
Vol 75 (23) ◽  
pp. 7409-7416 ◽  
Author(s):  
Ana Cláudia N. F. Spinelli ◽  
Anderson S. Sant'Ana ◽  
Salatir Rodrigues-Junior ◽  
Pilar R. Massaguer

ABSTRACT The prevention of spoilage by Alicyclobacillus acidoterrestris is a current challenge for fruit juice and beverage industries worldwide due to the bacterium's acidothermophilic growth capability, heat resistance, and spoilage potential. This study examined the effect of storage temperature on A. acidoterrestris growth in hot-filled orange juice. The evolution of the A. acidoterrestris population was monitored under six different storage conditions after pasteurization (at 92°C for 10 s), maintenance at 85°C for 150 s, and cooling with water spray to 35°C in about 30 min and using two inoculum levels: <101 and 101 spores/ml. Final cooling and storage conditions were as follows: treatment 1, 30°C for the bottle cold point and storage at 35°C; treatment 2, 30°C for 48 h and storage at 35°C; treatment 3, 25°C for the bottle cold point and storage at 35°C; treatment 4, 25°C for 48 h and storage at 35°C; treatment 5, storage at 20°C (control); and treatment 6, filling and storage at 25°C. It was found that only in treatment 5 did the population remain inhibited during the 6 months of orange juice shelf life. By examining treatments 1 to 4, it was observed that A. acidoterrestris predicted growth parameters were significantly influenced (P < 0.05) either by inoculum level or cooling and storage conditions. The time required to reach a 104 CFU/ml population of A. acidoterrestris was considered to be an adequate parameter to indicate orange juice spoilage by A. acidoterrestris. Therefore, hot-filled orange juice should be stored at or below 20°C to avoid spoilage by this microorganism. This procedure can be considered a safe and inexpensive alternative to other treatments proposed earlier.


Author(s):  
Lai Yan Xia ◽  
Hamidah Abu Bakar

Malaria is a life-threatening disease which has claimed many lives. Giemsa's stain is the gold standard method in malaria diagnosis. Generally, Giemsa's stain is diluted with buffered water. However, sometimes, it produces poor staining of the blood smears, in which can create a major challenge in detecting and identifying positive malaria parasites in a peripheral blood smear. This can lead to misdiagnosis and mistreatment to a patient. The present study examined the effect of replacing the buffered water to distilled water during the preparation of 3% Giemsa's solution. Blood specimens were collected from selected positive (n=80) and negative (n=300) malaria cases in EDTA tube. The modified method employed distilled water and different concentrations of buffered water for diluting Giemsa’s solution stock. The microscopy observation was performed on each set of blood film stained by both modified and standard Giemsa staining methods by two WHO’s qualified technicians. All Giemsa solutions with different diluents were comparable in detecting malaria parasites in the blood films. There was no difference between distilled water and different concentrations of buffered water. Furthermore, distilled water produced homogeneous staining and clearer background of the blood films, which enables different species of malaria to be identified. The present study demonstrates that the modified staining using distilled water in malaria parasites identification is comparable to the gold standard method. In addition, the modified method is rapid, easily available, cost-effective, and reliable.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Driss Ousaaid ◽  
Hamada Imtara ◽  
Hassan Laaroussi ◽  
Badiaa Lyoussi ◽  
Ilham Elarabi

Vinegar is a natural product rich in bioactive compounds such as phenols, flavonoids, and organic acids. Several factors affect the quality of vinegars such as apple origin, environmental conditions, production methods, processing, and storage conditions. We investigated the quality of apple vinegars as well as their physicochemical properties and the antioxidant and antibacterial activities of vinegars collected from different areas in Morocco. For physicochemical properties, the outcomes showed the following values: pH (3.18–3.83), electrical conductivity (2.11–2.90), acidity (0.24–5.6), Brix (3.25–6), and density (1.0123–1.0233). The polyphenols content of samples was 68.91 mg AG/100 mL in sample S6 as the minimum value and 147.54 mg AG/100 mL in sample S2 as the maximum value. The best ability to scavenge the DPPH radical was observed in sample S3 (IC50 = 0.45 ± 0.013 µL/mL). Sample S2 showed moderate antibacterial effect against microorganisms tested with MICs ranging from 0.78 µL/mL to 1.125 µL/mL and with a diameter of inhibition ranging from 15.65 mm to 27.65 mm. In addition, a strong correlation was observed between the antibacterial activity of vinegars and physicochemical parameters (pH and total acidity). These outcomes have shown that our vinegar samples are an excellent source of bioactive compounds with potent antioxidant and antibacterial potentials.


2021 ◽  
Vol 38 (1) ◽  
pp. 144-157
Author(s):  
Thaísa De Oliveira Silveira ◽  
Madelon Rodrigues Braz ◽  
Gilmara Pires de Moura Palermo ◽  
Tiago Böer Breier

Seeds of native forest species for food and seedling production have a growing demand that impacts the need for studies involving seed storage in order to maintain good levels of germination quality. Thus, scientific analyzes that explore the physiological potential of the seeds of these species are necessary, especially for the pink pepper (Schinus terebinthifolia Raddi.), a species used as an alternative source of income for traditional communities and which has been arousing interest due to the consumption of its fruits as a condiment in the national and international market. This work aimed to assess the physiological quality of pink pepper seeds according to the storage period and seed size. The seeds came from a rural settlement, a pioneer in the extraction of pink pepper, in the state of Rio de Janeiro, Brazil. The seeds were evaluated for moisture content, germination, first count, length and dry weight of the germinated seedlings, during the period of time that they remained stored and the size of the seeds. The results allowed to conclude that: i) the germinative percentage of the stored pink pepper seeds decreased over the months; ii) the moisture content of the seeds decreased over the months evaluated iii) the different sizes of seeds did not show differences in germination and storage time and iv) values of length and dry weight of the seedlings did not differ according to the period of storage.


2012 ◽  
Vol 466-467 ◽  
pp. 127-131
Author(s):  
Xiao Jie Zhang ◽  
Tong Min Jiang ◽  
Hua Luo ◽  
Xiao Rui Zhang

Due to the complex working and storage environment for airplanes, the consumptive failures of airborne products are unavoidable. Aiming at the problem that degradation behaviors that cause this kind of failures are frequently neglected, based on the concept of degradation for airborne products, a new method of conducting research that treats aging process as a critical degradation behavior is presented. According to the characteristics of airborne mechano-electronic products, steering engine is defined as a critical airplane airborne mechano-electronic product. Through detailed analysis of the vulnerable area of steering engine, the failure mechanism of aging of steering engine rubber seal is discussed. The degradation model of steering engine rubber seal is presented. Finally, feasibility of the method that replaces the research of degradation behavior of the airborne mechano-electronic products with that of aging is verified.


Author(s):  
André L. D. Goneli ◽  
Paulo C. Corrêa ◽  
Gabriel H. H. de Oliveira ◽  
Osvaldo Resende ◽  
Munir Mauad

ABSTRACT Sorption isotherms are of great importance in post-harvest procedures, especially for predicting drying and storage, which help to establish the final moisture content of the product under certain environmental condition. Hysteresis is a phenomenon that occurs due to the difference between adsorption and desorption curves, which aids the evaluation of chemical and microbiological deteriorations, indicating the stability of stored products. Moisture sorption isotherms of castor beans were determined and hysteresis was analyzed. Static gravimetric technique at different temperatures (25, 35, 45 and 55 ± 1 °C) was used. Saturated salt solutions in the range of 37-87% ± 2% were utilized to create the required controlled relative humidity environment. Equilibrium moisture content data were correlated by different mathematical models and the Modified Halsey model presented good adjustment for the data, according to statistical procedures. Hysteresis between adsorption and desorption isotherms is present over the range of 0.2-0.9 of water activity, regardless of the temperature. This phenomenon decreases with temperature increase.


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