Saadia Naseem

Strigolactones Biosynthesis and Their Role in Abiotic Stress Resilience in Plants: A Critical Review

Strigolactones (SLs), being a new class of plant hormones, play regulatory roles against abiotic stresses in plants. There are multiple hormonal response pathways, which are adapted by the plants to overcome these stressful environmental constraints to reduce the negative impact on overall crop plant productivity. Genetic modulation of the SLs could also be applied as a potential approach in this regard. However, endogenous plant hormones play central roles in adaptation to changing environmental conditions, by mediating growth, development, nutrient allocation, and source/sink transitions. In addition, the hormonal interactions can fine-tune the plant response and determine plant architecture in response to environmental stimuli such as nutrient deprivation and canopy shade. Considerable advancements and new insights into SLs biosynthesis, signaling and transport has been unleashed since the initial discovery. In this review we present basic overview of SL biosynthesis and perception with a detailed discussion on our present understanding of SLs and their critical role to tolerate environmental constraints. The SLs and abscisic acid interplay during the abiotic stresses is particularly highlighted. Main Conclusion: More than shoot branching Strigolactones have uttermost capacity to harmonize stress resilience.

Determination of macronutrients, micronutrients, non-essential elements in milk based-infant formulas by atomic absorption and inductively coupled plasma-optical emission spectroscopy after microwave and ultrasound assisted digestion

ABSTRACT Microwave and ultrasound procedures for samples preparations were adopted and the elements were determined by validated flame atomic absorption and inductively coupled plasma–optical emission spectrometry. Student’s t-test was established whether there was a difference between the sample preparation methods. Trueness of certified values by all methods was ensured which were not differing significantly at 95% level of confidence interval. The highest intensity ratio of magnesium (II)/magnesium (I) was obtained at 1120 radiofrequency value to achieve accurate and reproducible results by inductively coupled plasma–optical emission spectrometry. The value of corresponding correlation coefficient (r2) were obtained as >0.990 indicating the excellent linearity for concentration range chosen for each element to be determined in commercial samples. Results showed that concentrations of calcium, magnesium, potassium, sodium, chromium, copper, iron, manganese, selenium, and zinc found in commercially available products are in good agreement with label as declared by the manufacturers. Exposure to aluminum, cadmium, and lead from consumption of products under evaluation was estimated and it was in compliance with permissible level suggested by European Commission regulations. Regarding the food safety monitoring, the proposed methods are rapid and met green chemistry approach so that can be implemented in laboratories easily for routine analysis.

Efficient and reproducible somatic embryogenesis and micro propagation in tomato via novel structures -Rhizoid Tubers.

An improved and highly reproducible system for invitro regeneration via somatic embryogenesis (S.E), applicable to several varieties of tomato (cv. Riogrande, cv. Roma grande, hybrid 17905 and model cv. M82) has been developed. First, we developed a conventional indirect organogenesis for all four varieties used in this study. The cotyledons and hypocotyls of 6-day-old tomato were used as explants (1-2 cm) for callus induction (CI) on different callus induction media (CIM) T0 – T12 (6-Benzylaminopurine BAP, NAA Naphthalene acetic acid, ZEA Zeatin, IAA Indole-3-acetic acid, KIN Kinetin). Maximum CI response was seen on CIMT6 (0.5 mg/L NAA, 1 mg/L BAP) and CIMT7 (2 mg/L IAA, 2 mg/L NAA, 2 mg/L BAP, 4mg/L KIN) in a period of 2 weeks for commercial varieties cvs. Riogrande and Roma. However, cv. M82 responded after 4 weeks to a combination of treatments [CIMT6 (0.5 mg/L NAA + 1 mg/L BAP) and CIMT8 (2 mg/L IAA + 2 mg/L NAA + 2 mg/L BAP + 4 mg/L ZEA)] for the production of calli. The Riogrande, being the most responsive commercial variety, was selected for invitro morphogenesis via S.E. During S.E. young cotyledons and hypocotyls explants were tested on media with different ranges of pH (3 – 7) supplemented with 0.5 and 2 mg/L NAA. Resultantly, numerous rhizoids (~38) were produced from each explant at pH4 in dark conditions. Further incubation of each rhizoid under light conditions led to the formation of a novel structure - rhizoid tubers (RTBs) on MS media supplemented with 5 mg/L TDZ/BAP at pH4. We observed that only lower pH-induced rhizoids and RTBs regenerated into multiple individual shoots on media at normal pH (5.8). The RTBs led to a complete plantlets regeneration in 45 days compared to the conventional invitro morphogenesis (60 days).

Rotavirus: Genetics, pathogenesis and vaccine advances

Since its discovery 40 years ago, rotavirus (RV) is considered to be a major cause of infant and childhood morbidity and mortality particularly in developing countries. Nearly every child in the world under 5 years of age is at the risk of RV infection. It is estimated that 90% of RV‐associated mortalities occur in developing countries of Africa and Asia. Two live oral vaccines, RotaTeq (RV5, Merck) and Rotarix (RV1, GlaxoSmithKline) have been successfully deployed to scale down the disease burden in Europe and America, but they are less effective in Africa and Asia. In April 2009, the World Health Organization recommended the inclusion of RV vaccination in national immunization programs of all countries with great emphasis in developing countries. To date, 86 countries have included RV vaccines into their national immunization programs including 41 Global Alliance for Vaccines and Immunization eligible countries. The predominant RV genotypes circulating all over the world are G1P[8], G2P[4], G3P[8], G4P[8], and G9P[8], while G12[P6] and G12[P8] are emerging genotypes. On account of the segmented genome, RV shows an enormous genetic diversity that leads to the evolution of new genotypes that can influence the efficacy of current vaccines. The current need is for a global RV surveillance program to monitor the prevalence and antigenic variability of new genotypes to formulate future vaccine development planning. In this review, we will summarize the previous and recent insights into RV structure, classification, and epidemiology and current status of RV vaccination around the globe and will also cover the status of RV research and vaccine policy in Pakistan.

Investigations of Structural Requirements for BRD4 Inhibitors through Ligand- and Structure-Based 3D QSAR Approaches

The bromodomain containing protein 4 (BRD4) recognizes acetylated histone proteins and plays numerous roles in the progression of a wide range of cancers, due to which it is under intense investigation as a novel anti-cancer drug target. In the present study, we performed three-dimensional quantitative structure activity relationship (3D-QSAR) molecular modeling on a series of 60 inhibitors of BRD4 protein using ligand- and structure-based alignment and different partial charges assignment methods by employing comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) approaches. The developed models were validated using various statistical methods, including non-cross validated correlation coefficient (r2), leave-one-out (LOO) cross validated correlation coefficient (q2), bootstrapping, and Fisher’s randomization test. The highly reliable and predictive CoMFA (q2 = 0.569, r2 = 0.979) and CoMSIA (q2 = 0.500, r2 = 0.982) models were obtained from a structure-based 3D-QSAR approach using Merck molecular force field (MMFF94). The best models demonstrate that electrostatic and steric fields play an important role in the biological activities of these compounds. Hence, based on the contour maps information, new compounds were designed, and their binding modes were elucidated in BRD4 protein’s active site. Further, the activities and physicochemical properties of the designed molecules were also predicted using the best 3D-QSAR models. We believe that predicted models will help us to understand the structural requirements of BRD4 protein inhibitors that belong to quinolinone and quinazolinone classes for the designing of better active compounds.

Quantification of African cassava mosaic virus (ACMV) and East African cassava mosaic virus (EACMV-UG) in single and mixed infected Cassava (Manihot esculenta Crantz) using quantitative PCR.

The quantity of genomic DNA-A and DNA-B of African cassava mosaic virus (ACMV) and East African cassava mosaic virus Uganda (Uganda variant, EACMV-UG) was analysed using quantitative PCR to assess virus concentrations in plants from susceptible and tolerant cultivars. The concentrations of genome components in absolute and relative quantification experiments in single and mixed viral infections were determined. Virus concentration was much higher in symptomatic leaf tissues compared to non-symptomatic leaves and corresponded with the severity of disease symptoms. In general, higher titres were recorded for EACMV-UG Ca055 compared to ACMV DRC6. The quantitative assessment also showed that the distribution of both viruses in the moderately resistant cassava cv. TMS 30572 was not different from the highly susceptible cv. TME 117. Natural mixed infections with both viruses gave severe disease symptoms. Relative quantification of virus genomes in mixed infections showed higher concentrations of EACMV-UG DNA-A compared to ACMV DNA-A, but a marked reduction of EACMV-UG DNA-B. The higher concentrations of EACMV-UG DNA-B compared to EACMV DNA-A accumulation in single infections were consistent. Since DNA-B is implicated in virus cell-to-cell spread and systemic movement, the abundance of the EACMV-UG DNA-B may be an important factor driving cassava mosaic disease epidemic.