Deploying aptameric sensing technology for rapid pandemic monitoring

The genome of virulent strains may possess the ability to mutate by means of antigenic shift and/or antigenic drift as well as being resistant to antibiotics with time. The outbreak and spread of these virulent diseases including avian influenza (H1N1), severe acute respiratory syndrome (SARS-Corona virus), cholera (Vibrio cholera), tuberculosis (Mycobacterium tuberculosis), Ebola hemorrhagic fever (Ebola Virus) and AIDS (HIV-1) necessitate urgent attention to develop diagnostic protocols and assays for rapid detection and screening. Rapid and accurate detection of first cases with certainty will contribute significantly in preventing disease transmission and escalation to pandemic levels. As a result, there is a need to develop technologies that can meet the heavy demand of an all-embedded, inexpensive, specific and fast biosensing for the detection and screening of pathogens in active or latent forms to offer quick diagnosis and early treatments in order to avoid disease aggravation and unnecessary late treatment costs. Nucleic acid aptamers are short, single-stranded RNA or DNA sequences that can selectively bind to specific cellular and biomolecular targets. Aptamers, as new-age bioaffinity probes, have the necessary biophysical characteristics for improved pathogen detection. This article seeks to review global pandemic situations in relation to advances in pathogen detection systems. It particularly discusses aptameric biosensing and establishes application opportunities for effective pandemic monitoring. Insights into the application of continuous polymeric supports as the synthetic base for aptamer coupling to provide the needed convective mass transport for rapid screening is also presented.     

A model of a digital biological ecosystem

In this paper, we propose a model of a digital biological ecosystem of fish. Collections of fish data by scientists in Malaysia have been converted and developed into a digital biological ecosystem using computational technology and methods. We used a combination of Geographical Information System, databases and ontologies for storing, retrieving and visualizing fish species distribution and their abundance as well as their relationship with the environment. We used ArcGIS to build the fish and environmental geodatabase, which is linked to Google Earth for real-time visualization, and Surfer 8 to create contour maps which are superimposed as layers on the ArcGIS interface. Individual fish species on the map are hyperlinked to the FishBase Portal (http://www.fishbase.org/) while the published map is displayed using ArcReader. The three databases that we created contain information about fish species, environment and contours. These are also integrated using a fish ontology which will link all the available information for various fish species. The proposed system can be adopted by marine scientists to better convince economists, fishery managers, coastal developers and government bodies who make important decisions on conservation policies and laws.     

Ameliorative Role of Pre-Sowing Proline Treatment in <i>Coriandrum sativum</i> L. Seedlings under Mercury Toxicity

Heavy metal toxicity is one of the major ecosystem concerns globally in present time and is also responsible for significant threat to agronomic crops. The current work was conducted to investigate the possible ameliorative role of proline in Coriandrum sativum L. seedlings treated with mercury (Hg). The seedlings were exposed to different concentrations of Hg (0, 0.1, 0.3 and 0.5 mM) for 20 days. The effects of pre-sowing treatment with proline were studied on C. sativum seedlings in terms of pigment (chlorophylls, carotenoids and anthocyanins), malondialdehyde (MDA), antioxidant compound (glutathione, total phenolic compounds, ascorbic acid) and osmolytes (proline, glycine betaine). Additionally, activities of antioxidant enzymes, namely catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) were also studied. A strong decline of photosynthetic pigment concentrations was observed in leaves of C. sativum under Hg toxicity. Treatment of seeds with proline reduced the loss of photosynthetic pigments, counteract Hg-triggered oxidative stress, likely preserving the functionality of antioxidant apparatus under Hg stress. The increment of total polyphenols and glycine betaine also contributed in ameliorating Hg toxicity, suggesting the use of exogenous proline as a potential method to enhance the plant tolerance against heavy metal stress.     

An Ethylmethane Sulfonate Mutant Resource in Pre-Green Revolution Hexaploid Wheat

Mutagenesis is a powerful tool used for studying gene function as well as for crop improvement. It is regaining popularity because of the development of effective and cost efficient methods for high-throughput mutation detection. Selection for semi-dwarf phenotype during green revolution has reduced genetic diversity including that for agronomically desirable traits. Most of the available mutant populations in wheat (Triticum aestivum L.) were developed in post-green revolution cultivars. Besides the identification and isolation of agronomically important alleles in the mutant population of pre-green revolution cultivar, this population can be a vital resource for expanding the genetic diversity for wheat breeding. Here we report an Ethylmethane Sulfonate (EMS) generated mutant population consisting of 4,180 unique mutant plants in a pre-green revolution spring wheat cultivar ‘Indian’. Released in early 1900s, ‘Indian’ is devoid of any known height-reducing mutations. Unique mutations were captured by proceeding with single M₂ seed from each of the 4,180 M₁ plants. Mutants for various phenotypic traits were identified by detailed phenotyping for altered morphological and agronomic traits on M₂ plants in the greenhouse and M₃ plants in the field. Of the 86 identified mutants, 75 (87%) were phenotypically stable at the M₄ generation. Among the observed phenotypes, variation in plant height was the most frequent followed by the leaf morphology. Several mutant phenotypes including looped peduncle, crooked plant morphology, ‘gritty’ coleoptiles, looped lower internodes, and burnt leaf tips are not reported in other plant species. Considering the extent and diversity of the observed mutant phenotypes, this population appears to be a useful resource for the forward and reverse genetic studies. This resource is available to the scientific community.     

Brassinosteroids Regulate Functional Components of Antioxidative Defense System in Salt Stressed Maize Seedlings

Journal of Plant Growth Regulation - The purpose of current investigation was to explore the role of brassinosteroids (BRs) in Zea mays L. var. DKC 9106 seedlings subjected to salt stress. The...     

The Polo-like kinase PLKA in Aspergillus nidulans is not essential but plays important roles during vegetative growth and development

The Polo-like kinases (Plks) are conserved, multifunctional cell cycle regulators that are induced in many forms of cancer and play additional roles in metazoan development. We previously identified plkA in Aspergillus nidulans, the only Plk investigated in filamentous fungi to date, and partially characterized its function through overexpression. Here, we report the plkA null phenotype. Surprisingly, plkA was not essential, unlike Plks in other organisms that contain a single homologue. A subset of cells lacking PLKA contained defects in spindle formation and chromosome organization, supporting some conservation in cell cycle function. However, septa were present, suggesting that PLKA, unlike other Plks, is not a central regulator of septation. Colonies lacking PLKA were compact with multibranched hyphae, implying a role for this factor in aspects of hyphal morphogenesis. These defects were suppressed by high temperature or low concentrations of benomyl, suggesting that PLKA may function during vegetative growth by influencing microtubule dynamics. However, the colonies also showed reduced conidiation and precocious formation of sexual Hülle cells in a benomyl- and temperature-insensitive manner. This result suggests that PLKA may influence reproduction through distinct mechanisms and represents the first example of a link between Plk function and development in fungi. Finally, filamentous fungal Plks have distinct features, and phylogenetic analyses reveal that they may group more closely with metazoan PLK4. In contrast, yeast Plks are more similar to metazoan proteins PLK1 to PLK3. Thus, A. nidulans PLKA shows some conservation in cell cycle function but may also play novel roles during hyphal morphogenesis and development.     

Biophysical characterization of layer‐by‐layer synthesis of aptamer‐drug microparticles for enhanced cell targeting

Targeted delivery of drug molecules to specific cells in mammalian systems demonstrates a great potential to enhance the efficacy of current pharmaceutical therapies. Conventional strategies for pharmaceutical delivery are often associated with poor therapeutic indices and high systemic cytotoxicity, and this result in poor disease suppression, low surviving rates, and potential contraindication of drug formulation. The emergence of aptamers has elicited new research interests into enhanced targeted drug delivery due to their unique characteristics as targeting elements. Aptamers can be engineered to bind to their cognate cellular targets with high affinity and specificity, and this is important to navigate active drug molecules and deliver sufficient dosage to targeted malignant cells. However, the targeting performance of aptamers can be impacted by several factors including endonuclease‐mediated degradation, rapid renal filtration, biochemical complexation, and cell membrane electrostatic repulsion. This has subsequently led to the development of smart aptamer‐immobilized biopolymer systems as delivery vehicles for controlled and sustained drug release to specific cells at effective therapeutic dosage and minimal systemic cytotoxicity. This article reports the synthesis and in vitro characterization of a novel multi‐layer co‐polymeric targeted drug delivery system based on drug‐loaded PLGA‐Aptamer‐PEI (DPAP) formulation with a stage‐wise delivery mechanism. A thrombin‐specific DNA aptamer was used to develop the DPAP system while Bovine Serum Albumin (BSA) was used as a biopharmaceutical drug in the synthesis process by ultrasonication. Biophysical characterization of the DPAP system showed a spherical shaped particulate formulation with a unimodal particle size distribution of average size ～0.685 µm and a zeta potential of +0.82 mV. The DPAP formulation showed a high encapsulation efficiency of 89.4 ± 3.6%, a loading capacity of 17.89 ± 0.72 mg BSA protein/100 mg PLGA polymeric particles, low cytotoxicity and a controlled drug release characteristics in 43 days. The results demonstrate a great promise in the development of DPAP formulation for enhanced in vivo cell targeting. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:249–261, 2018     

Glutathione Peroxidases in Plants: Innumerable Role in Abiotic Stress Tolerance and Plant Development

Journal of Plant Growth Regulation - Glutathione peroxidases (GPXs) are key reactive oxygen species (ROS) scavenging enzyme that catalyses the reduction of H2O2 to prevent the cellular machinery...