Shaukat Ali

Bio: Shaukat Ali is an academic researcher from Government College University. The author has contributed to research in topics: Zebrafish & Cadmium chloride. The author has an hindex of 14, co-authored 73 publications receiving 1081 citations. Previous affiliations of Shaukat Ali include VU University Amsterdam & University of Azad Jammu and Kashmir.

Zebrafish Embryos and Larvae: A New Generation of Disease Models and Drug Screens

Abstract: Technological innovation has helped the zebrafish embryo gain ground as a disease model and an assay system for drug screening. Here, we review the use of zebrafish embryos and early larvae in applied biomedical research, using selected cases. We look at the use of zebrafish embryos as disease models, taking fetal alcohol syndrome and tuberculosis as examples. We discuss advances in imaging, in culture techniques (including microfluidics), and in drug delivery (including new techniques for the robotic injection of compounds into the egg). The use of zebrafish embryos in early stages of drug safety-screening is discussed. So too are the new behavioral assays that are being adapted from rodent research for use in zebrafish embryos, and which may become relevant in validating the effects of neuroactive compounds such as anxiolytics and antidepressants. Readouts, such as morphological screening and cardiac function, are examined. There are several drawbacks in the zebrafish model. One is its very rapid development, which means that screening with zebrafish is analogous to "screening on a run-away train." Therefore, we argue that zebrafish embryos need to be precisely staged when used in acute assays, so as to ensure a consistent window of developmental exposure. We believe that zebrafish embryo screens can be used in the pre-regulatory phases of drug development, although more validation studies are needed to overcome industry scepticism. Finally, the zebrafish poses no challenge to the position of rodent models: it is complementary to them, especially in early stages of drug research.

Large-scale assessment of the zebrafish embryo as a possible predictive model in toxicity testing.

Abstract: Background In the drug discovery pipeline, safety pharmacology is a major issue. The zebrafish has been proposed as a model that can bridge the gap in this field between cell assays (which are cost-effective, but low in data content) and rodent assays (which are high in data content, but less cost-efficient). However, zebrafish assays are only likely to be useful if they can be shown to have high predictive power. We examined this issue by assaying 60 water-soluble compounds representing a range of chemical classes and toxicological mechanisms. Methodology/Principal Findings Over 20,000 wild-type zebrafish embryos (including controls) were cultured individually in defined buffer in 96-well plates. Embryos were exposed for a 96 hour period starting at 24 hours post fertilization. A logarithmic concentration series was used for range-finding, followed by a narrower geometric series for LC50 determination. Zebrafish embryo LC50 (log mmol/L), and published data on rodent LD50 (log mmol/kg), were found to be strongly correlated (using Kendall's rank correlation tau and Pearson's product-moment correlation). The slope of the regression line for the full set of compounds was 0.73403. However, we found that the slope was strongly influenced by compound class. Thus, while most compounds had a similar toxicity level in both species, some compounds were markedly more toxic in zebrafish than in rodents, or vice versa. Conclusions For the substances examined here, in aggregate, the zebrafish embryo model has good predictivity for toxicity in rodents. However, the correlation between zebrafish and rodent toxicity varies considerably between individual compounds and compound class. We discuss the strengths and limitations of the zebrafish model in light of these findings.

Large-Scale Analysis of Acute Ethanol Exposure in Zebrafish Development: A Critical Time Window and Resilience

Abstract: Background In humans, ethanol exposure during pregnancy causes a spectrum of developmental defects (fetal alcohol syndrome or FAS) Individuals vary in phenotypic expression Zebrafish embryos develop FAS-like features after ethanol exposure In this study, we ask whether stage-specific effects of ethanol can be identified in the zebrafish, and if so, whether they allow the pinpointing of sensitive developmental mechanisms We have therefore conducted the first large-scale (>1500 embryos) analysis of acute, stage-specific drug effects on zebrafish development, with a large panel of readouts Methodology/Principal Findings Zebrafish embryos were raised in 96-well plates Range-finding indicated that 10% ethanol for 1 h was suitable for an acute exposure regime High-resolution magic-angle spinning proton magnetic resonance spectroscopy showed that this produced a transient pulse of 086% concentration of ethanol in the embryo within the chorion Survivors at 5 days postfertilisation were analysed Phenotypes ranged from normal (resilient) to severely malformed Ethanol exposure at early stages caused high mortality (≥88%) At later stages of exposure, mortality declined and malformations developed Pharyngeal arch hypoplasia and behavioral impairment were most common after prim-6 and prim-16 exposure By contrast, microphthalmia and growth retardation were stage-independent Conclusions Our findings show that some ethanol effects are strongly stage-dependent The phenotypes mimic key aspects of FAS including craniofacial abnormality, microphthalmia, growth retardation and behavioral impairment We also identify a critical time window (prim-6 and prim-16) for ethanol sensitivity Finally, our identification of a wide phenotypic spectrum is reminiscent of human FAS, and may provide a useful model for studying disease resilience

Current state and prospects of the phytosynthesized colloidal gold nanoparticles and their applications in cancer theranostics

Abstract: The design, development, and biomedical applications of phytochemical-based green synthesis of biocompatible colloidal gold nanoparticles (AuNPs) are becoming an emerging field due to several advantages (safer, eco-friendly, simple, fast, energy efficient, low-cost, and less toxic) over conventional chemical synthetic procedures. Biosynthesized colloidal gold nanoparticles are remarkably attractive in several biomedical applications including cancer theranostics due to small size, unusual physico-chemical properties, facile surface modification, high biocompatibility, and numerous other advantages. Of late, several researchers have investigated the biosynthesis and prospective applications (diagnostics, imaging, drug delivery, and cancer therapeutics) of AuNPs in health care and medicine. However, not a single review article is available in the literature that demonstrates the anti-cancer potential of biosynthesized colloidal AuNPs with detailed mechanistic study. In the present review article, we for the first time discuss the biointerface of colloidal AuNPs, plants, and cancer mainly (i) comprehensive mechanistic aspects of phytochemical-based synthesis of AuNPs; (ii) proposed anti-cancer mechanisms along with biomedical applications in diagnostics, imaging, and drug delivery; and (iii) key challenges for biogenic AuNPs as future cancer nanomedicine.

Dewatering of microalgal cultures : a major bottleneck to algae-based fuels

Abstract: Microalgae dewatering is a major obstruction to industrial-scale processing of microalgae for biofuel prodn. The dil. nature of harvested microalgal cultures creates a huge operational cost during dewatering, thereby, rendering algae-based fuels less economically attractive. Currently there is no superior method of dewatering microalgae. A technique that may result in a greater algal biomass may have drawbacks such as a high capital cost or high energy consumption. The choice of which harvesting technique to apply will depend on the species of microalgae and the final product desired. Algal properties such as a large cell size and the capability of the microalgae to autoflocculate can simplify the dewatering process. This article reviews and addresses the various technologies currently used for dewatering microalgal cultures along with a comparative study of the performances of the different technologies.

Bioactive compounds and bioactivities of ginger (zingiber officinale roscoe)

Abstract: Ginger (Zingiber officinale Roscoe) is a common and widely used spice. It is rich in various chemical constituents, including phenolic compounds, terpenes, polysaccharides, lipids, organic acids, and raw fibers. The health benefits of ginger are mainly attributed to its phenolic compounds, such as gingerols and shogaols. Accumulated investigations have demonstrated that ginger possesses multiple biological activities, including antioxidant, anti-inflammatory, antimicrobial, anticancer, neuroprotective, cardiovascular protective, respiratory protective, antiobesity, antidiabetic, antinausea, and antiemetic activities. In this review, we summarize current knowledge about the bioactive compounds and bioactivities of ginger, and the mechanisms of action are also discussed. We hope that this updated review paper will attract more attention to ginger and its further applications, including its potential to be developed into functional foods or nutraceuticals for the prevention and management of chronic diseases.

The role of pretreatment in improving the enzymatic hydrolysis

Abstract: Lignocellulosic materials are among the most promising alternative energy resources that can be utilized to produce cellulosic ethanol. However, the physical and chemical structure of lignocellulosic materials forms strong native recalcitrance and results in relatively low yield of ethanol from raw lignocellulosic materials. An appropriate pretreatment method is required to overcome this recalcitrance. For decades various pretreatment processes have been developed to improve the digestibility of lignocellulosic biomass. Each pretreatment process has a different specificity on altering the physical and chemical structure of lignocellulosic materials. In this paper, the chemical structure of lignocellulosic biomass and factors likely affect the digestibility of lignocellulosic materials are discussed, and then an overview about the most important pretreatment processes available are provided. In particular, the combined pretreatment strategies are reviewed for improving the enzymatic hydrolysis of lignocellulose and realizing the comprehensive utilization of lignocellulosic materials.