Laser-induced fluorescence spectroscopy for early disease detection in grapefruit plants

Biotic and abiotic stress both cause a considerable decrease in the chlorophyll content in plant leaves, which provides a means for the early diagnosis of diseases in plants. The emergence of diseases affects the fluorescence of phenolic compounds and chlorophyll, which have emissions located at 530, 686 and 735 nm. Herein, it was found that the intensity of the emission band of phenolic compounds at 530 nm increased and that of chlorophyll at 735 nm decreased with the onset of diseases. Statistical analysis through principal component analysis (PCA) and partial least squares regression (PLSR) was performed, which differentiated between apparently healthy leaf sites and diseased leaves, providing a basis for the detection of diseases in the early stages. The PLSR model was validated through the coefficient of determination (R²), standard error of prediction (SEP) and standard error of calibration (SEC) with the values of 0.99, 0.394 and 0.0.401, respectively, which authenticated the model. The prediction accuracy of the model was evaluated through root mean square error in prediction (RMSEP), with a value of 0.14, by predicting 22 unknown emission spectra of different leaf sites. Both the PCA and PLSR models produced similar results, proving that fluorescence spectroscopy is an excellent tool for early disease detection in plants.

141 Effect of combined treatment of melatonin and equine chorionic gonadotrophin on fresh semen quality of Beetal bucks during the non-breeding season

In the subtropics, bucks show seasonal breeding patterns, and their semen quality decreases during the non-breeding season. Therefore, breeders tend to improve bucks’ semen quality before the breeding season for higher conception rates. In the current study, we hypothesised that simultaneous administration of equine chorionic gonadotrophin (ECG) and melatonin would improve fresh semen quality in bucks before the breeding season. Nine Beetal bucks were randomly assigned (n=3 per treatment) to three treatments: control, melatonin, and melatonin + ECG. Melatonin implants (18 mg; BTC Lab) were placed subcutaneously at the base of the ear. Bucks in the melatonin + ECG treatment were administered ECG (400 IU; Syncro-Part, Ceva Santé Animale) intramuscularly on every fourth day until the end of the experiment. Control bucks were administered normal saline (400 IU; Otuska Pakistan) intramuscularly on every fourth day. Semen was collected twice per week using an artificial vagina (42°C) and immediately evaluated for volume, color, pH, and contaminants. Sperm concentration, motility and kinematics (curvilinear velocity, straight-line velocity, average path velocity, and amplitude of lateral head displacement), viability, DNA, and acrosomal and mitochondrial integrity were monitored using a computer-assisted semen analyzer (AndroVision, Minitube). Weekly concentrations of plasma testosterone and melatonin of all bucks were analysed using radioimmunoassay (Immunotech, Beckman Coulter Ltd.) and enzyme-linked immunosorbent assay (450nm), respectively. Comparisons within and between treatments were made using generalised linear models (repeated-measures analysis of variance). Weekly single-point variance between the treatments was determined (analysis of variance) at P ≤ 0.05 (SPSS ver. 20.0; IBM Corp.). Semen quality (volume, pH, total motility (%), and concentration) improved after Week 4 in the melatonin + ECG treatment compared with the control and melatonin treatments (P<0.05). Similarly, progressive motility (%), viability, DNA, acrosomal and mitochondrial integrity, and sperm kinematics (curvilinear velocity, straight-line velocity, average path velocity, and amplitude of lateral head displacement) improved (P<0.05) after Week 4 in the melatonin + ECG treatment. Similarly, non-viability and ratio of abnormal spermatozoa decreased by Week 3 in the melatonin + ECG treatment (P<0.05) compared with the control and melatonin treatments. Likewise, plasma testosterone concentration (ngmL−1) of bucks was higher (P<0.05) at Week 3 in the melatonin + ECG treatment (4.2±0.2) than in the melatonin (0.8±0.1) and control (1.2±0.1) treatments. Within the melatonin + ECG treatment, plasma testosterone concentration was higher (P<0.05) at Week 5 (4.9±0.2) and Week 9 (4.5±0.1) than at Week 3 (4.2±0.2). Plasma melatonin concentration (pgmL−1) increased (P<0.05) from Week 5 onward in the melatonin + eCG (12.5±0.1) and melatonin (10.2±0.1) treatments compared with the control (2.65±0.1). In conclusion, the simultaneous administration of melatonin and ECG improved fresh semen quality in Beetal bucks.

Metabolic engineering of Yarrowia lipolytica for thermoresistance and enhanced erythritol productivity

BACKGROUND

Functional sugar alcohols have been widely used in the food, medicine, and pharmaceutical industries for their unique properties. Among these, erythritol is a zero calories sweetener produced by the yeast Yarrowia lipolytica. However, in wild-type strains, erythritol is produced with low productivity and yield and only under high osmotic pressure together with other undesired polyols, such as mannitol or d-arabitol. The yeast is also able to catabolize erythritol in non-stressing conditions.

RESULTS

Herein, Y. lipolytica has been metabolically engineered to increase erythritol production titer, yield, and productivity from glucose. This consisted of the disruption of anabolic pathways for mannitol and d-arabitol together with the erythritol catabolic pathway. Genes ZWF1 and GND encoding, respectively, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were also constitutively expressed in regenerating the NADPH₂ consumed during erythritol synthesis. Finally, the gene RSP5 gene from Saccharomyces cerevisiae encoding ubiquitin ligase was overexpressed to improve cell thermoresistance. The resulting strain HCY118 is impaired in mannitol or d-arabitol production and erythritol consumption. It can grow well up to 35 °C and retain an efficient erythritol production capacity at 33 °C. The yield, production, and productivity reached 0.63 g/g, 190 g/L, and 1.97 g/L·h in 2-L flasks, and increased to 0.65 g/g, 196 g/L, and 2.51 g/L·h in 30-m³ fermentor, respectively, which has economical practical importance.

CONCLUSION

The strategy developed herein yielded an engineered Y. lipolytica strain with enhanced thermoresistance and NADPH supply, resulting in a higher ability to produce erythritol, but not mannitol or d-arabitol from glucose. This is of interest for process development since it will reduce the cost of bioreactor cooling and erythritol purification.

Van der Waals heterostructures of SiC and Janus MSSe (M = Mo, W) monolayers: a first principles study

Favorable stacking patterns of two models with alternative orders of chalcogen atoms in SiC-MSSe (M = Mo, W) vdW heterostructures are investigated using density functional theory calculations. Both model-I and model-II of the SiC-MSSe (M = Mo, W) vdW heterostructures show type-II band alignment, while the spin orbit coupling effect causes considerable Rashba spin splitting. Furthermore, the plane-average electrostatic potential is also calculated to investigate the potential drops across the heterostructure and work function. The imaginary part of the dielectric function reveals that the first optical transition is dominated by excitons with high absorption in the visible region for both heterostructures. Appropriate band alignments with standard water redox potentials enable the capability of these heterostructures to dissociate water into H⁺/H₂ and O₂/H₂O.

Using DFT calculations, we have investigated the electronic structure, Rashba effect, optical and photocatalytic performance of SiC-MSSe (M = Mo, W) van der Waals heterostructures with different stacking patterns of chalcogen atoms.

H-D Analysis Employing Energy Transfer from Metastable Excited-State He in Double-Pulse LIBS with Low-Pressure He Gas

A laser-induced-breakdown-spectroscopy (LIBS) experiment with a unique double-pulse setup and operated in low-pressure (3 kPa) He ambient gas is performed to study the detection of light elements, such as hydrogen (H) and deuterium (D), as well as elements of high excitation energies, such as fluorine (F) and chlorine (Cl), which are usually difficult to detect using ordinary LIBS techniques. A nanosecond Nd:YAG laser operated in its fundamental wavelength with energy of 54 mJ is focused onto the Al target to generate the He plasma. Another picosecond Nd:YAG laser operated in its fundamental wavelength with energy of 2 mJ is focused onto the sample surface and activated 2 μs before the operation of the nanosecond laser. The application to polyvinyl chloride (PVC) and polytetrafluoroethylene (PTFE) samples produces sharp and high-intensity Cl- and F-emission lines. Meanwhile, the sharp and well-resolved H-D-emission lines with merely 0.18 nm wavelength separation are also clearly detected from a zircaloy sample. Further measurement of a set of zircaloy samples containing different concentrations of D yields a linear calibration curve with a zero intercept. The detection limit of D is found to be about 10 ppm.

Antimicrobial, antioxidant, cytotoxicity and LC-MS analyses of Aerva javanica: an ethnomedicinally important plant

In this study, Aerva javanica was used to extract the essential oil with notable medicinal activities. The chemical composition was investigated by high-performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry (LC-MS). Ten major chemical compounds were identified as flavonoids derivatives, dihydroxylated and glycosylated metabolites. The antimicrobial, antioxidant, and cytotoxicity activities were tested using agar well-diffusion assay, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free-radical scavenging and linoleic acid oxidation assays and hemolytic assay against human erythrocytes (RBCs), respectively. Plant extracts exhibited different extents of antimicrobial activities against selected bacterial and fungal strains; however, the essential oil displayed potent antimicrobial activity against all the tested strains. The percentage inhibition of linoleic acid oxidation and inhibitory concentration (IC50) were recorded to be in the range of 42.45-96.21% and 14.21-38.18 μg/mL, respectively. Cytotoxicity profile of A. javanica extracts and essential oil was found in the range of 5.82 to 14.47%. In conclusion, A. javanica essential oil could be a potential alternative to chemical additives in the food and pharmaceutical industries.

Soret and Dufour Effects on Three Dimensional Upper-Convected Maxwell Fluid with Chemical Reaction and Non-Linear Radiative Heat Flux

Three dimensional chemically reactive upper-convected Maxwell (UCM) fluid flow over a stretching surface is considered to examine Soret and Dufour effects on heat and mass transfer. During the formulation of energy equation, non-linear radiative heat flux is considered. Similarity transformation reduces the partial differential equations of flow problem into ordinary differential equations. These non-linear differential equations are then solved by using bvp4c MATLAB built-in function. A comparison of the present results with the published work is also included. Effects of some prominent parameters such as Soret and Dufour number, chemical reaction parameter, Prandtl number, Schmidt number and thermal radiation on velocity, temperature and concentration are discussed graphically and numerically. A comparison with the previously published work is also included in a tabular form.

Significant effect of NSP-ase enzyme supplementation in sunflower meal-based diet on the growth and nutrient digestibility in broilers

The response of broiler chickens to 3 levels of sunflower meal and 2 levels of NSP-ase enzyme combination (with and without) was investigated in 3 × 2 factorial arrangement under complete randomized design (CRD). A total of 240 Hubbard broiler chicks were fed on practical mash diets having 2950 kcal of ME and 21% CP from 1 to 42 days of age. The BW gain was not significantly reduced when 25% SFM was added in the diets during 1 to 42 days of age. Supplementation of NSP-ase in broiler diets (day 1-42 overall) demonstrated non-significant differences (p < 0.05) across the treatments in terms of FI and BWG. The difference in feed:gain at 15% or 20% SFM was observed to be non-significant. Replacement of SBM with SFM or inclusion of SFM at higher level (25%) increased/deteriorated FCR. The addition of exogenous NSP-ase showed a significant improvement (p < 0.01) in feed:gain. The improvement was clearly demonstrated when SFM was added to the experimental diet at 15% or even 20%. Supplementation of NSP-ase at the 25% inclusion level could not, however, sustain the beneficial effect, which was possibly due to excessively high dietary CF. No difference was noted across the treatments regarding carcass response. Relative gizzard weight and intestinal weight were observed to be improved in birds consuming higher levels of SFM (p = 0.00). The digestibility of CF was observed to improve when SFM was used at 20% and 25% in the diets. No improvement in the digestibility of CF was observed with NSP-ase supplementation, which meant other factors were clearly involved. Supplementation of NSP-ase improved FCR up to 20% SFM. At 25% SFM, no improvement in the digestibility of CF was observed with NSP-ase supplementation.

Time-domain reconstruction using sensitivity coefficients for limited view ultrawide band tomography

This article addresses time-domain ultrawide band (UWB) electromagnetic tomography for reconstructing the unknown spatial characteristic of an object from observations of the arrivals of short electromagnetic (EM) pulses. Here, the determination of the first peak arrival of the EM traces constitutes the forward problem, and the inverse problem aims to reconstruct the EM property distribution of the media. In this article, the finite-difference time-domain method implementing a perfectly matched layer is used to solve the forward problem from which the system sensitivity maps are determined. Image reconstruction is based on the combination of a linearized update and regularized Landweber minimization algorithm. Experimental data from a laboratory UWB system using targets of different contrasts, sizes, and shapes in an aqueous media are presented. The results show that this technique can accurately detect and locate unknown targets in spite of the presence of significant levels of noise in the data.