Reference gene selection for qRT-PCR analyses of luffa (Luffa cylindrica) plants under abiotic stress conditions.

Selecting suitable internal reference genes is an important prerequisite for the application of quantitative real-time PCR (qRT-PCR). However, no systematic studies have been conducted on reference genes in luffa. In this study, seven reference genes were selected, and their expression levels in luffa plants exposed to various simulated abiotic stresses [i.e., cold, drought, heat, salt, H2O2, and abscisic acid (ABA) treatments] were analyzed by qRT-PCR. The stability of the reference gene expression levels was validated using the geNorm, NormFinder, BestKeeper, and RefFinder algorithms. The results indicated that EF-1α was the most stably expressed and suitable reference gene overall and for the heat, cold, and ABA treatments. Additionally, UBQ expression was stable following the salt treatment, whereas TUB was identified as a suitable reference gene for H2O2 and drought treatments. The reliability of the selected reference genes was verified by analyzing the expression of copper/zinc superoxide dismutase (Cu/Zn-SOD) gene in luffa. When the most unstable reference genes were used for data normalizations, the resulting expression patterns had obvious biases when compared with the expression patterns for the most ideal reference genes used alone or combined. These results will be conducive to more accurate quantification of gene expression levels in luffa.

Optimization of Hydrothermal and Diluted Acid Pretreatments of Tunisian Luffa cylindrica (L.) Fibers for 2G Bioethanol Production through the Cubic Central Composite Experimental Design CCD: Response Surface Methodology.

This paper opens up a new issue dealing with Luffa cylindrica (LC) lignocellulosic biomass recovery in order to produce 2G bioethanol. LC fibers are composed of three principal fractions, namely, α-cellulose (45.80% ± 1.3), hemicelluloses (20.76% ± 0.3), and lignins (13.15% ± 0.6). The optimization of LC fibers hydrothermal and diluted acid pretreatments duration and temperature were achieved through the cubic central composite experimental design CCD. The pretreatments optimization was monitored via the determination of reducing sugars. Then, the 2G bioethanol process feasibility was tested by means of three successive steps, namely, LC fibers hydrothermal pretreatment performed at 96°C during 54 minutes, enzymatic saccharification carried out by means of a commercial enzyme AP2, and the alcoholic fermentation fulfilled with Saccharomyces cerevisiae. LC fibers hydrothermal pretreatment liberated 33.55 g/kg of reducing sugars. Enzymatic hydrolysis allowed achieving 59.4 g/kg of reducing sugars. The conversion yield of reducing sugar to ethanol was 88.66%. After the distillation step, concentration of ethanol was 1.58% with a volumetric yield about 70%.

Remediation of Cu metal-induced accelerated Fenton reaction by potato peels bio-sorbent.

This article has allied exposure to Ecological Particulate Matter (EPM) and its remediation using potato peel surface (PPC) bio-sorbent on two important edible crops Spinacia oleracea and Luffa acutangula. Fenton reaction acceleration was one of the major stress oxidation reactions as a consequence of iron and copper toxicity, which involve in the formation of hydroxyl radical (OH) through EPM. Results showed that the oxidative stress encouraged by Cu in both species that recruits the degradation of photosynthetic pigments, initiating decline in growth, reduced leaf area and degrade proteins. The plants were cultivated in natural environmental condition in three pots with three replicates like (a) control, (b) Cu treated and (c) treated water. Oxidative stress initiated by metal activity in Cu accumulated plant (b) were controlled, through bio-sorption of metal from contaminated water using PPC; arranged at laboratory scale. The acceleration of Fenton reaction was verified in terms of OH radical generation. These radicals were tested in aqueous extract of leaves of three types of plants via benzoic acid. The benzoic acid acts as a scavenger of OH radical due to which the decarboxylation of benzoic acid cured. Observation on (b) showed more rapid decarboxylation as compared to other plants which showed that Cu activity was much higher in (b) as compared to (a) and (c). The rapid decarboxylation of benzoic acid and lower chlorophyll contents in (b) suggest that Fenton reaction system was much enhanced by Cu-O and Fe-O chemistry that was successfully controlled by PPC which results in restoring the metabolic pathway and nullifying oxidative stress in

Investigating the roles of ascorbate-glutathione cycle and thiol metabolism in arsenate tolerance in ridged Luffa seedlings.

The present study is aimed to investigate whether ascorbate-glutathione cycle (AsA-GSH cycle) or thiol metabolism is involved in the regulation of arsenate (As(V))-induced oxidative stress and tolerance in ridged Luffa seedlings. As(V) significantly (p < 0.05) declined the growth of Luffa seedlings which was accompanied by the enhanced accumulation of As. The enhanced accumulation of As in tissues declined total protein and nitrogen contents and photosynthesis, and increased the accumulation of reactive oxygen species (ROS). The enhanced levels of ROS cause damage to lipids and proteins as indicated by the increased contents of malondialdehyde (MDA) and reactive carbonyl groups (RCG). The components of AsA-GSH cycle such as ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and reduced ascorbate were downregulated, while glutathione reductase and glutathione were upregulated by As(V) stress. Thiol metabolic enzymes such as cysteine synthase, γ-glutamylcysteine synthetase, and glutathione synthetase, and compounds such as cysteine, glutathione, and non-protein thiols were stimulated by As(V) stress. These results suggest that thiol metabolism plays a key role in mitigating As(V)-mediated further damage to Luffa seedlings, while AsA-GSH cycle components had a little role in imparting As(V) tolerance. The present study provides information regarding the involvement of AsA-GSH cycle and thiol metabolism in imparting As(V) tolerance in Luffa. The results of this study can be utilized for As(V) toxicity management in Luffa while keeping these biochemical components into consideration.

Water-responsive rapid recovery of natural cellular material.

Insight into the stimuli-responsive behaviour of biological materials with hierarchical microstructures is essential for designing new sustainable materials and structures. Shape memory, self-healing and self-repairing will become valuable characteristics of advanced materials. Here we report the water-triggered shape recovery of a natural biological material, the luffa sponge. The longitudinally crushed luffa sponge column can recover up to 98% of its original shape after it is immersed in water. The mechanical properties of the luffa sponge can also be recovered, to a large extent, after a subsequent drying process. The effects of strain rate, crushing strains, loading cycles, and temperature/duration of water treatment of the drying process on the shape recovery ratio and the energy dissipation recovery ratio have been investigated. The results from this study have demonstrated that the luffa sponge material possesses remarkable shape memory effects and mechanical recovery features which could be exploited or biomimicked for the design of water-responsive smart materials undergoing large deformations.

Nitric oxide alleviates arsenic-induced toxic effects in ridged Luffa seedlings.

Hydroponic experiments were conducted to investigate whether exogenous addition of nitric oxide (NO) as sodium nitroprusside (SNP) alleviates arsenic (As) toxicity in Luffa acutangula (L.) Roxb. seedlings. Arsenic (5 and 50 µM) declined growth of Luffa seedlings which was accompanied by significant accumulation of As. SNP (100 µM) protected Luffa seedlings against As toxicity as it declined As accumulation significantly. The photosynthetic pigments and chlorophyll fluorescence parameters such as Fv/Fm, Fv/F0, Fm/F0 and qP were decreased while NPQ was raised by As. However, the toxic effects of As on photosynthesis were significantly ameliorated by SNP. The oxidative stress markers such as superoxide radical, hydrogen peroxide and malondialdehyde (lipid peroxidation) contents were enhanced by As, however, these oxidative indices were diminished significantly in the presence of SNP. As treatment stimulated the activities of SOD and CAT while the activities of APX and GST, and AsA content and AsA/DHA ratio were decreased. Upon SNP addition, along with further rise in SOD and CAT activity, APX and GST activity, and levels of AsA and AsA/DHA ratio were restored considerably. Overall results revealed that significant accumulation of As suppressed growth, photosynthesis, APX and GST activities and decreased AsA content, hence led to the oxidative stress. However, the addition of SNP protected seedlings against As stress by regulating As accumulation, oxidative stress and antioxidant defense system.