Phenotypic and microarray analysis reveals salinity stress-induced oxidative tolerance in transgenic rice expressing a DEAD-box RNA helicase, OsDB10.

Helicases are the motor proteins not only involved in the process of mRNA metabolism but also played a significant role in providing abiotic stresses tolerance. In this study, a DEAD-box RNA helicase OsDB10 was cloned and functionally characterized. The transcript levels of OsDB10 were increased both in shoot and root upon salt, heat, cold, and ABA application and was more prominent in shoot compared to root. Genomic integration of OsDB10 in transgenic rice was confirmed by PCR, Southern blot and qRT-PCR analysis. The transgenic plants showed quicker seed germination, reduced necrosis, higher chlorophyll, more survival rate, better seedling growth, and produced more grain yield under salinity stress. Furthermore, transgenic lines also accumulated less Na+ and high K+ ions and salinity tolerance of the transgenic were also assayed by measuring different bio-physiological indices. Moreover, the OsDB10 transgenic plants showed enhanced tolerance to salinity-induced oxidative stress by scavenging ROS and increased activity of antioxidants enzymes. Microarray analysis showed upregulation of transcriptional regulations and metabolic reprogramming as OsDB10 overexpression modulates the expression of many other genes. Altogether, our results confirmed that OsDB10 is a functional DEAD-box RNA helicase and played vital roles in plant defence response against salinity stress.

A DEAD box helicase Psp68 positively regulates salt stress responses in marker-free transgenic rice plants.

Helicases are the motor proteins not only involved in transcriptional and post-transcription process but also provide abiotic stress tolerance in many crops. The p68, belong to the SF2 (DEAD-box helicase) family proteins and overexpression of Psp68 providing enhanced tolerance to transgenic rice plants. In this study, salinity tolerant marker-free transgenic rice has been developed by overexpressing Psp68 gene and phenotypically characterized. The Psp68 overexpressing marker-free transgenic rice plants were initially screened in the rooting medium containing salt stress and 20% polyethylene glycol (PEG). Stable integration and overexpression of Psp68 in marker-free transgenic lines were confirmed by molecular analyses including PCR, southern, western blot, and qRT-PCR analyses. The marker-free transgenic lines showed enhanced tolerance to salinity stress as displayed by early seed germination, higher chlorophyll content, reduced necrosis, more survival rate, improved seedling growth and more grain yield per plant. Furthermore, Psp68 overexpressing marker-free transgenics also accumulated less Na+ and higher K+ ions in the presence of salinity stress. Phenotypic analyses also revealed that marker-free transgenic rice lines efficiently scavenge ROS-mediated damages as displayed by lower H2O2 and malondialdehyde content, delayed electrolyte leakage, higher photosynthetic efficiency, membrane stability, proline content and enhanced activities of antioxidants enzymes. Overall, our results confirmed that Psp68 overexpression confers salinity stress tolerance in marker-free transgenics, hence the technique could be utilized to develop genetically modified crops without any biosafety issues.

Novel Probiotic Lactic Acid Bacteria with In Vitro Bioremediation Potential of Toxic Lead and Cadmium.

In this study, newly isolated lactic acid bacteria (LAB) were screened for the potential bioremediation capacity against toxic lead (Pb, II) and cadmium (Cd, II) with their bioaccessibility and survivability. Five strains were selected from eighteen previously isolated probiotic LAB strains based on heavy metal-resistant potentiality through in vitro disc-diffusion assay. These five strains were evaluated in vitro to explore the Pb and Cd binding and removal efficiencies using Flame Atomic Absorption Spectrophotometry. At the same time, their bioaccessibility and survivability were assessed in a dynamic in vitro gastrointestinal digestion model. The results revealed that all the tested strains were shown to have a high magnitude of minimum inhibitory concentration values ranging from 500 to 2000 mg/L with 5 to 25 mm growth inhibition zones. The results also demonstrated a significant (P < 0.05) removal of Pb and Cd among five tested LAB strains. Lactobacillus delbrueckii subsp. bulgaricus LDMB02 showed the highest removal rates of Pb and Cd. It was also revealed that these strains significantly reduced Pb and Cd bioaccessibility from 42 to 50% and 40 to 58%, respectively. Moreover, these strains were shown to have significant survivability against Pb and Cd, ranging from 80.1 to 85.4% and 81.5 to 87.5%, respectively. This study recommends the immense potential exploit of LAB as a probiotic to protect human health from the adverse effects of Pb and Cd toxicity.

Fatty acid and amino acid profiles of cheese, butter, and ghee made from buffalo milk.

Objective: The objective was to assess the chemical composition, cholesterol, fatty acid (FAs), and amino acid (AAs) profiles of buffalo cheese, butter, and ghee. Materials and Methods: Buffalo milk (raw) was collected from the Bangladesh Agricultural University (BAU) Dairy Farm, BAU, Mymensingh-2202, Bangladesh. Cheese, butter, and ghee were prepared at the Dairy Chemistry and Technology Laboratory, Department of Dairy Science, BAU, Mymensingh, Bangladesh, and subjected to subsequent analyses. The gross nutritional composition and AAs profile of milk were analyzed prior to the manufacture of cheese, butter, and ghee. The gross nutritional composition of milk and dairy products was analyzed by applying an automated milk analyzer and the Association of Agricultural Chemists techniques, respectively. The cholesterol, FAs, and AAs contents of cheese, butter, and ghee were determined by the Bangladesh Council for Scientific and Industrial Research, Dhaka, Bangladesh. Furthermore, atherogenic and thrombogenic indices were also calculated using reference equations. Results: The results indicated that the buffalo milk is a good source of first-rate nutrients (dry matter: 16.50%, fat: 7.50%, protein: 3.75%). Findings indicated that the butter was significantly rich with (p < 0.05) total solids and fat where higher (p > 0.05) protein, carbohydrate, and minerals were found in cheese. The saponification, Reichert-Meissl, Polenski, and Kirschner values of buffalo ghee were found to be 225, 30, 1.2, and 25, respectively. A significant (p < 0.05) variation was found in the cholesterol content of buffalo cheese, butter, and ghee. Butter and ghee had 40.14 and 39.57 mg more cholesterol, respectively, than cheese. The results revealed identical FA profiles except for C24:0 among the three dairy products where the major FA compositions were C4:0, C14:0, C16:0, and C18:0 and C18:1 cis-9. The atherogenicity index and thrombogenicity index of cheese, butter, and ghee were statistically similar (p > 0.05). Butter was found with the most conducive anti-atherogenic and anti-thrombogenic characteristics due to lower saturated and higher polyunsaturated FAs. However, all the AAs concentrations were statistically higher (p < 0.05) in cheese than in butter and ghee. Conclusion: To conclude, buffalo cheese is superior to butter and ghee as regards nutrient density, but consumers can choose other foods based on their choice.

Physicochemical characteristics, sensory profile, probiotic, and starter culture viability of synbiotic yogurt.

Objectives: This study aimed to envisage the effectiveness of adding three particular prebiotics (inulin, ß-glucan, and Hi-maize) to synbiotic yogurt's physicochemical properties, sensory characteristics, and survivability of the probiotic and starter cultures. Materials and Methods: The yogurt's gross composition, syneresis, water-holding capacity (WHC), viscosity, sensorial properties, and probiotic and starter cell stability were analyzed. The Lactobacillus delbrueckii subsp. bulgaricus M240-5 and Streptococcus thermophilus M140-2 were employed as yogurt starter bacteria, and Lactobacillus acidophilus LA-5 as probiotic culture. The synbiotic yogurt was formulated with 5% sucrose and 0.7% artificial vanilla flavor. Results: The findings showed that when prebiotic ingredients were added to synbiotic yogurt, it had a significant impact on its sensory qualities, WHC, syneresis, and viscosity when compared to plain yogurt samples. The prebiotics did not affect the pH and titratable acidity of the yogurt samples. Additionally, the prebiotic supplementation did not influence the protein and fat content of synbiotic yogurt (p < 0.05). Prebiotics had an impact on the probiotic cell viability and total viable count (p < 0.05) compared to the plain sample, the 2.5% ß-glucan, 1.5% and 2.5% Hi-maize samples had the highest mean viability (8.95 Log CFU/ml). The starter culture ratio remained stable in response to the prebiotic levels. Conclusion: In summary, the production of synbiotic yogurts supplemented with Hi-maize and ß-glucan at 1.5% and 2.5%, respectively, is highly advised because these supplementations provide yogurt with acceptable syneresis, viscosity, WHC, and sensory attributes.

Variations in fatty acid and amino acid profiles of doi and rasomalai made from buffalo milk.

OBJECTIVE: This study investigated and compared the chemical composition, cholesterol content, fatty acid (FA), and amino acid (AA) profiles of doi and rasomalai made from buffalo milk. MATERIALS AND METHODS: Bangladesh Agricultural University Dairy Farm, Mymensingh-2202, Bangladesh was the source of raw buffalo milk. Then, doi and rasomalai were produced and analyzed. Prior to the production of doi and rasomalai, the gross composition and AAs of milk were evaluated. Milk and dairy products were evaluated for gross composition using an automated milk analyzer and the Association of Agricultural Chemists techniques, respectively. At the Bangladesh Council for Scientific and Industrial Research, Dhaka, Bangladesh, the cholesterol, FA, and AA levels of doi and rasomalai were determined. Additionally, atherogenic and thrombogenic indices were determined using established equations. RESULTS: The results indicated that the majority of the proximate components were significantly greater (p < 0.05) in rasomalai than in doi. Rasomalai had 3.64 mg more cholesterol (p > 0.05) than doi. The FA profile was identical across doi and rasomalai with the exception of oleic acid (C18:1cis-9), which was 1.50% greater (p < 0.05) in rasomalai. The atherogenicity index was found to be statistically higher in doi than in rasomalai (p > 0.05). Similarly, the thrombogenic index was found to be significantly higher (p > 0.05) in doi (1.98) when compared to the rasomalai (1.92). The concentrations of all AAs were found to be quantitatively higher in doi than in rasomalai (p > 0.05). CONCLUSION: The conclusion is that buffalo milk rasomalai appears to have a higher nutritional density than buffalo milk doi.

Comparative Transcriptome Analysis of Early- and Late-Bolting Traits in Chinese Cabbage (Brassica rapa).

Chinese cabbage is one of the most important and widely consumed vegetables in China. The developmental transition from the vegetative to reproductive phase is a crucial process in the life cycle of flowering plants. In spring-sown Chinese cabbage, late bolting is desirable over early bolting. In this study, we analyzed double haploid (DH) lines of late bolting ("Y410-1" and "SY2004") heading Chinese cabbage (Brassica rapa var. pekinensis) and early-bolting Chinese cabbage ("CX14-1") (B. rapa ssp. chinensis var. parachinensis) by comparative transcriptome profiling using the Illumina RNA-seq platform. We assembled 721.49 million clean high-quality paired-end reads into 47,363 transcripts and 47,363 genes, including 3,144 novel unigenes. There were 12,932, 4,732, and 4,732 differentially expressed genes (DEGs) in pairwise comparisons of Y410-1 vs. CX14-1, SY2004 vs. CX14-1, and Y410-1 vs. SY2004, respectively. The RNA-seq results were confirmed by reverse transcription quantitative real-time PCR (RT-qPCR). A Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of DEGs revealed significant enrichment for plant hormone and signal transduction as well as starch and sucrose metabolism pathways. Among DEGs related to plant hormone and signal transduction, six unigenes encoding the indole-3-acetic acid-induced protein ARG7 (BraA02g009130), auxin-responsive protein SAUR41 (BraA09g058230), serine/threonine-protein kinase BSK11 (BraA07g032960), auxin-induced protein 15A (BraA10g019860), and abscisic acid receptor PYR1 (BraA08g012630 and BraA01g009450), were upregulated in both late bolting Chinese cabbage lines (Y410-1 and SY2004) and were identified as putative candidates for the trait. These results improve our understanding of the molecular mechanisms underlying flowering in Chinese cabbage and provide a foundation for studies of this key trait in related species.

Molecular cloning of putative chloroplastic cysteine synthase in Leucaena leucocephala.

Cysteine biosynthesis is directed by the successive commitments of serine acetyltransferase, and O-acetylserine (thiol) lyase (OASTL) compounds, which subsequently frame the decameric cysteine synthase complex. The isoforms of OASTL are found in three compartments of the cell: the cytosol, plastid, and mitochondria. In this investigation, we first isolated putative chloroplastic OASTL (Ch-OASTL) from Leucaena leucocephala, and the Ch-OASTL was then expressed in BL21-competent Escherichia coli. The putative Ch-OASTL cDNA clone had 1,543 base pairs with 391 amino acids in its open reading frame and a molecular weight of 41.54 kDa. The purified protein product exhibited cysteine synthesis ability, but not mimosine synthesis activity. However, they both make the common α-aminoacrylate intermediate in their first half reaction scheme with the conventional substrate O-acetyl serine (OAS). Hence, we considered putative Ch-OASTL a cysteine-specific enzyme. Kinetic studies demonstrated that the optimum pH for cysteine synthesis was 7.0, and the optimum temperature was 40 °C. In the cysteine synthesis assay, the Km and kcat values were 838 ± 26 µM and 72.83 s-1 for OAS, respectively, and 60 ± 2 µM and 2.43 s-1 for Na2S, respectively. We can infer that putative Ch-OASTL regulatory role is considered a sensor for sulfur constraint conditions, and it acts as a forerunner of various metabolic compound molecules.

Sensitive fluorescent microplate bioassay using recombinant Escherichia coli with multiple promoter-reporter units in tandem for detection of arsenic.

Genetically modified bacterial biosensors can detect specific environmental compounds. Here, we attempted to establish a fluorescent microplate method to detect arsenic using recombinant Escherichia coli cells transformed with plasmids harboring three tandem copies of the ars promoter/operator-the gene for green fluorescent protein (gfp). In the biosensors, one copy of arsR, whose transcription is autoregulated by the ars promoter/operator and ArsR in the genome of E. coli, was placed in trans in another plasmid under the control of isopropyl-1-thio-beta-D-galactopyranoside-inducible promoter. First, this manipulation enabled regulation of the arsR expression at an adequate level. Second, the copy number of reporter unit also affected signal and noise. When the plasmid harboring three copies of the reporter unit was used, the signal-to-noise ratio doubled and the detection limit decreased from 20 to 7.5 microg L(-1) As(III), compared to the use of the plasmid harboring one copy of the ars promoter/operator-arsR-gfp. Thus, segregation of arsR from the ars promoter/operator-gfp using two plasmids is effective in regulating the signal-to-noise ratio and the detection limit with the different functions.