Semi-High Throughput Screening for Potential Drought-tolerance in Lettuce (Lactuca sativa) Germplasm Collections

This protocol describes a method by which a large collection of the leafy green vegetable lettuce (Lactuca sativa L.) germplasm was screened for likely drought-tolerance traits. Fresh water availability for agricultural use is a growing concern across the United States as well as many regions of the world. Short-term drought events along with regulatory intervention in the regulation of water availability coupled with the looming threat of long-term climate shifts that may lead to reduced precipitation in many important agricultural regions has increased the need to hasten the development of crops adapted for improved water use efficiency in order to maintain or expand production in the coming years. This protocol is not meant as a step-by-step guide to identifying at either the physiological or molecular level drought-tolerance traits in lettuce, but rather is a method developed and refined through the screening of thousands of different lettuce varieties. The nature of this screen is based in part on the streamlined measurements focusing on only three water-stress indicators: leaf relative water content, wilt, and differential plant growth following drought-stress. The purpose of rapidly screening a large germplasm collection is to narrow the candidate pool to a point in which more intensive physiological, molecular, and genetic methods can be applied to identify specific drought-tolerant traits in either the lab or field. Candidates can also be directly incorporated into breeding programs as a source of drought-tolerance traits.     

EPA Method 1615. Measurement of Enterovirus and Norovirus Occurrence in Water by Culture and RT-qPCR. I. Collection of Virus Samples

EPA Method 1615 was developed with a goal of providing a standard method for measuring enteroviruses and noroviruses in environmental and drinking waters. The standardized sampling component of the method concentrates viruses that may be present in water by passage of a minimum specified volume of water through an electropositive cartridge filter. The minimum specified volumes for surface and finished/ground water are 300 L and 1,500 L, respectively. A major method limitation is the tendency for the filters to clog before meeting the sample volume requirement. Studies using two different, but equivalent, cartridge filter options showed that filter clogging was a problem with 10% of the samples with one of the filter types compared to 6% with the other filter type. Clogging tends to increase with turbidity, but cannot be predicted based on turbidity measurements only. From a cost standpoint one of the filter options is preferable over the other, but the water quality and experience with the water system to be sampled should be taken into consideration in making filter selections.     

From water‐in‐oil to oil‐in‐water emulsions to optimize the production of fatty acids using ionic liquids in micellar systems

Biocatalysis is nowadays considered as one of the most important tools in green chemistry. The elimination of multiple steps involved in some of the most complex chemical synthesis, reducing the amounts of wastes and hazards, thus increasing the reaction yields and decreasing the intrinsic costs, are the major advantages of biocatalysis. This work aims at improving the enzymatic hydrolysis of olive oil to produce valuable fatty acids through emulsion systems formed by long alkyl chain ionic liquids (ILs). The optimization of the emulsion and the best conditions to maximize the production of fatty acids were investigated. The stability of the emulsion was characterized considering the effect of several parameters, namely, the IL and its concentration and different water/olive oil volumetric ratios. ILs from the imidazolium and phosphonium families were evaluated. The results suggest that the ILs effect on the hydrolysis performance varies with the water concentration and the emulsion system formed, that is, water‐in‐oil or oil‐in‐water emulsion. Although at low water concentrations, the presence of ILs does not present any advantages for the hydrolysis reaction, at high water contents (in oil‐in‐water emulsions), the imidazolium‐based IL acts as an enhancer of the lipase catalytic capacity, super‐activating 1.8 times the enzyme, and consequently promoting the complete hydrolysis of the olive oil for the highest water contents [85% (v/v)]. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:1473–1480, 2015     

Fine root production of Pinus massoniana plantation and Castanopsis carlesii plantation at different successional stages in subtropical China

AimsOur objectives were to determine differences in fine root production, its relationships with environmental factors, and its diameter- and depth-related distribution patterns between plantations of two subtropical tree species differing in successional stages. MethodsPlantation forests of an early-successional species, Pinus massoniana, and a late-successional species, Castanopsis carlesii, in Sanming, Fujian Province, were selected. Fine root production was monitored for two years using minirhizotrons methods. At the same time, environmental factors including monthly air temperature, monthly precipitation, soil temperature, and soil water content were determined.Important findings 1) During the two years, there was significant difference in annual fine root length production between these two forests, with annual production of P. massoniana plantation nearly four times that of C. carlesii plantation. Fine root length production under both forests showed significant monthly dynamics and maximized in summer, a season when most of fine roots were born. 2) Roots of 0-0.3 mm in diameter accounted for the largest proportion of total fine root length production. Fine roots were concentrated mostly at the 0-10 cm soil depth in P. massoniana plantation, but happened mostly at the 30-40 cm soil depth in the C. carlesii plantation. 3) Partial correlation analysis suggested that, monthly fine root production of both forests was significantly correlated with both air temperature and soil temperature, while it had no significant correlation with either rainfall or soil water content. Linear regression analysis illustrated that monthly fine root production was more correlated with air temperature and soil temperature in the P. massoniana plantation than in the C. carlesii plantation. It was concluded that fine root production in the early-successional P. massoniana plantation was not only much higher in amount, but also more sensitive to temperature, than that in the late-successional C. carlesii plantation.     

灌水量和滴灌施肥方式对温室黄瓜产量和品质的影响

以黄瓜为试验材料,研究灌水量和滴灌施肥方式对日光温室黄瓜生长、产量和品质的影响.设两个水分水平(100％ET0,W1;75％ET0,W2)和4种滴灌施肥方式处理,不同滴灌施肥方式处理按推荐施肥量(N∶P2 O5∶K2 O分别为360∶180∶540 kg·hm-2)的100％、66.6％、33.3％、0％(Z100、Z66、Z33、Z0)分8次滴灌施肥,剩余肥料一次性基施;另设不施肥处理为对照(CK).结果表明:滴灌施肥比例和水分与黄瓜的株高、叶面积、干物质量、产量和品质均呈正相关关系.W1 Z100处理的产量最高(67760 kg·hm-2);W2处理的平均水分利用效率比W1处理高9.4％,其中W2Z100处理的水分利用效率最高(47.71 kg·m-3),其产量比最高产量低3.4％却节水25％.与Z0相比,Z100的黄瓜产量和干物质量分别增加15.3％和16.8％;同时,黄瓜果实中维生素C、可溶性蛋白和可溶性糖含量增加;水分利用效率增加19.1％.W2Z100处理为温室黄瓜高产、优质、节水的最佳处理.     

Substrate water exchange in photosystem II core complexes of the extremophilic red alga Cyanidioschyzon merolae

The binding affinity of the two substrate–water molecules to the water-oxidizing Mn₄CaO₅ catalyst in photosystem II core complexes of the extremophilic red alga Cyanidioschyzon merolae was studied in the S₂ and S₃ states by the exchange of bound ¹⁶O-substrate against ¹⁸O-labeled water. The rate of this exchange was detected via the membrane-inlet mass spectrometric analysis of flash-induced oxygen evolution. For both redox states a fast and slow phase of water-exchange was resolved at the mixed labeled m/z 34 mass peak: k_f = 52 ± 8 s^− 1 and k_s = 1.9 ± 0.3 s^− 1 in the S₂ state, and k_f = 42 ± 2 s^− 1 and k_slow = 1.2 ± 0.3 s^− 1 in S₃, respectively. Overall these exchange rates are similar to those observed previously with preparations of other organisms. The most remarkable finding is a significantly slower exchange at the fast substrate–water site in the S₂ state, which confirms beyond doubt that both substrate–water molecules are already bound in the S₂ state. This leads to a very small change of the affinity for both the fast and the slowly exchanging substrates during the S₂ → S₃ transition. Implications for recent models for water-oxidation are briefly discussed.     

Prior hydration of Brassica tournefortii seeds reduces the stimulatory effect of karrikinolide on germination and increases seed sensitivity to abscisic acid

Background and Aims

The smoke-derived compound karrikinolide (KAR₁) shows significant potential as a trigger for the synchronous germination of seeds in a variety of plant-management contexts, from weed seeds in paddocks, to native seeds when restoring degraded lands. Understanding how KAR₁ interacts with seed physiology is a necessary precursor to the development of the compound as an efficient and effective management tool. This study tested the ability of KAR₁ to stimulate germination of seeds of the global agronomic weed Brassica tournefortii, at different hydration states, to gain insight into how the timing of KAR₁ applications in the field should be managed relative to rain events.

Methods

Seeds of B. tournefortii were brought to five different hydration states [equilibrated at 15 % relative humidity (RH), 47 % RH, 96 % RH, fully imbibed, or re-dried to 15 % RH following maximum imbibition] then exposed to 1 nm or 1 µm KAR₁ for one of five durations (3 min, 1 h, 24 h, 14 d or no exposure).

Key Results

Dry seeds with no history of imbibition were the most sensitive to KAR₁; sensitivity was lower in seeds that were fully imbibed or fully imbibed then re-dried. In addition, reduced sensitivity to KAR₁ was associated with an increased sensitivity to exogenously applied abscisic acid (ABA).

Conclusions

Seed water content and history of imbibition were found to significantly influence whether seeds germinate in response to KAR₁. To optimize the germination response of seeds, KAR₁ should be applied to dry seeds, when sensitivity to ABA is minimized.     

Comparative NMR studies of diffusional water permeability of red blood cells from different species: XVIII platypus (Ornithorhynchus anatinus) and saltwater crocodile (Crocodylus porosus)

As part of a programme of comparative measurements of P _d (diffusional water permeability) the RBCs (red blood cells) from an aquatic monotreme, platypus (Ornithorhynchus anatinus), and an aquatic reptile, saltwater crocodile (Crocodylus porosus) were studied. The mean diameter of platypus RBCs was estimated by light microscopy and found to be ～6.3 μm. P _d was measured by using an Mn²⁺‐doping 1H NMR (nuclear magnetic resonance) technique. The P _d (cm/s) values were relatively low: ～2.1×10^?3 at 25°C, 2.5×10^?3 at 30°C, 3.4×10^?3 at 37°C and 4.5 at 42°C for the platypus RBCs and ～2.8×10^?3 at 25°C, 3.2×10^?3 at 30°C, 4.5×10^?3 at 37°C and 5.7×10^?3 at 42°C for the crocodile RBCs. In parallel with the low water permeability, the E _a,d (activation energy of water diffusion) was relatively high, ～35 kJ/mol. These results suggest that “conventional” WCPs (water channel proteins), or AQPs (aquaporins), are probably absent from the plasma membranes of RBCs from both the platypus and the saltwater crocodile.     

Fishing gears involved in entanglements of minke whales (Balaenoptera acutorostrata) in the East Sea of Korea

Entanglement of marine mammals in fishing gear is a global issue. It is considered a significant threat to minke whales (Balaenoptera acutorostrata) in the East Sea of Korea. A total of 214 entanglements of minke whales in this area between 2004 and 2007 were used to investigate types and parts of fishing gears involved in entanglements. The majority of entanglements were mainly caused by three types of fishing gears: set nets, pots, and gill nets (n= 207, 96.7%). Other entanglements were associated with bottom trawls, purse seines, and trawls. A total of 65 entanglements were attributed to the main and branch lines of fishing gears. The most common body part of minke whales which attached to fishing gears was the mouth (n= 63, 30.4%). Most entanglements took place within 10 nmi from land (n= 179, 86.5%), and between 10 and 220 m of water depth. The mean length of entangled minke whales in set nets was significantly smaller than that of whales in pots and gill nets samples (P < 0.001). Also, the mean body length of minke whales that entangled in the coastal area and shallow waters was significantly shorter than that of whales in the offshore area and deep waters (P < 0.001). This information can be used as fundamental data to conserve and manage this population of minke whales in the East Sea of Korea, and also to modify fishing gear to reduce entanglements. Future studies should focus on investigating the impact of these entanglements on the population and the effectiveness of mitigation measures to reduce entanglements of minke whales in this area.     

An automated screening method for drugs and toxic compounds in human serum and urine using liquid chromatography–tandem mass spectrometry

A fully automated screening using liquid chromatography–mass spectrometric method applying data-dependent acquisition was developed to identify toxicologically relevant substances in serum and urine. A library including more than 405 spectra of about 365 compounds (main drugs and important metabolites) was established. An easy to use program was created to automate and accelerate library search. Drugs were identified based on their relative retention times, molecular ions and fragment ions. Limits of detection were tested with 100 of the 365 compounds the majority of these were lower than 100 μg/l (67%). The developed LC–MS–MS system seems to be a valuable alternative to other general unknown screening methods allowing fast and specific identification of drugs in serum and urine samples.