Qualitative Screening Method Research Articles

Qualitative discrimination of low-dose oral contraceptives and identification of environmentally stressed tablets: Comparing a handheld near infrared spectrometer to a benchtop spectrometer

Levonorgestrel – ethinyl estradiol tablets (Levo-EE) are an essential medication provided through global health supply chains for family planning purposes. Ensuring the quality of Levo-EE and other essential medications in a global supply chain is a primary concern. Portable and handheld diffuse reflectance spectrometers have become more approachable from a cost and usability perspective in recent years. A discriminatory screening method with a handheld near infrared (NIR) spectrometer (900 – 1700 nm) differentiating between brands of Levo-EE and placebos has been constructed. Additionally, the handheld spectrometer was used to determine if environmentally stressed tablets could be identified and differentiated in a qualitative screening method. The same samples were scanned on a benchtop diffuse reflectance NIR spectrometer as well (350 – 2500 nm) for comparison. Brands of oral contraceptives were able to be discriminated by applying a Mahalanobis distance-based classification approach to the handheld spectrometer, though be it at a slightly lower level of discernability due to the reduced spectral range collected. Environmentally stressed samples were applied to the classification model, which were flagged as unlike the reference dataset. Spectra from the environmentally stressed tablets saw an increase in absorbance for water associated peaks with the benchtop spectrometer at approximately 1450 nm and 1949 nm for tablets stored at 30, 40, and 50°C–54°C. Data collected by the handheld showed that the spectrometer offers a low-cost screening approach to oral contraceptive tablets containing two low-dose active ingredients. The handheld spectrometer was also able to flag environmentally stressed samples. The total model accuracy for the target product (brand “A”; N = 560) was above 98% for both benchtop and handheld spectrometers. While these results focus on oral contraceptives, a similar approach could be conducted for other solid dosage tablets for more approachable quality compliance screening.

Investigating Seasonal Variation in The Phytochemical and Antioxidant Capacities of Different Sphagnum Taxa

This study investigated the phytochemical content and antioxidant activities of four Sphagnum taxa (S. centrale, S. palustre, S. teres and, S. auriculatum) collected from the Black Sea region of Turkey during two different seasons. The phytochemical groups in the methanol extracts of Sphagnum taxa were identified using qualitative screening methods. The total phenol content of these taxa was quantitatively determined using Folin-ciocalteu reagent with gallic acid equivalents as the standard their antioxidant activities were evaluated by 1,2-diphenyl-1-picrylhydrazyl free radical scavenging ability (DPPH), the CUPRAC test, and phosphomolybdenum assay. Qualitative phytochemical screening of the methanol extracts showed that phenols, tannins, and saponins were present in the extracts, whereas alkaloids and flavonoids were absent. The highest DPPH free radical scavenging activity was observed in 100 µgmL-1 S. teres methanol extract (74.47±0.001% in the first season, September 2021 and 75.37±0.002% in the second season, May 2022). The highest total antioxidant capacity was found in 100 µgmL-1 S. palustre extract (81.00±0.027% in the first season and 84.87±0.002% in the second season). The results of our experiment showed that Sphagnum taxa collected in spring had higher antioxidant activity than those collected in autumn.

Application of chimeric antigens to paper-based diagnostics for detection of West Nile virus infections of Crocodylus porosus – A novel animal test case

Laboratory-based diagnostics such as plaque reduction neutralisation tests (PRNT) and ELISA are commonly used to detect seroconversion to flavivirus infections. However, faster, qualitative screening methods are essential for quicker diagnosis and improved patient outcomes. Lateral flow assays (LFAs) offer rapid results (5–15 mins) at the point-of-care, but few commercial flavivirus antibody detection LFAs are available.We developed an LFA using novel chimeric viral antigens produced by genetically modifying the mosquito restricted Binjari virus (BinJV) to display the outer virion proteins of pathogenic viruses like West Nile virus (WNV). The BinJV chimeric platform offers several advantages for diagnostic assay development, including rapid construction of new chimeras in response to emerging viral variants, safe, scalable antigen manufacturing, and structural indistinguishability to the wild-type pathogenic virion.To demonstrate feasibility, we applied the chimeric WNV (BinJV/WNV) antigen to LFA as the capture/test line reagent for detecting seroconversion in crocodilians to WNV – a virus affecting crocodilians across multiple continents. We confirmed the antigenic conservation of the chimera on the LFA detection surface using monoclonal antibodies. Utilising well-characterised sera (n=60) from WNV-seropositive or flavivirus-naive Australian saltwater crocodiles (Crocodylus porosus), the assay exhibited 98.8 % sensitivity and 100 % specificity, with results obtained in under 15 minutes. The LFA also accurately detected seroconversion in animals experimentally infected with WNV.This qualitative screening method can be performed both inside and outside of a laboratory, and the assay design will guide the optimisation of similar tests for detecting vector-borne viral infections in humans and other animals.

A screening method for detection of TiO2 in food based on Raman spectroscopy and its applicability in a regulatory context

Starting from August 7, 2022, with the publication of the European Regulation EU 2022/63, the European Commission has prohibited the use of titanium dioxide (TiO2) (E 171) as a food additive within the European Union (EU). As the food industry has the obligation to adapt the formulation of their products accordingly, it is now crucial for EU member states' competent authorities and official control laboratories to have adequate analytical methods to ensure compliance with this new regulation. The existing literature predominantly focuses on quantitatively determining the elemental titanium (Ti) concentration by ICP-based techniques after complete digestion of the analyte and the food matrix. Compared to this approach, Raman spectroscopy would offer the possibility of a more rapid albeit qualitative screening by identifying the insoluble fraction of titanium dioxide after removing the food matrix. It is also important to note that compliance with the EU ban requires determining the presence of TiO2 in particulate form, an information that Raman spectroscopy can easily deliver. As a further advantage, an analytical approach based on Raman spectroscopy eliminates the need for using particularly harmful acids, which are necessary for the complete digestion of TiO2, when ICP-based analytical methods are employed. In the present study, the aim was first to gather information on the commonly occurring total Ti levels in food and, second, to discuss the potential of a newly developed Raman procedure based on TiO2 extraction by mild acid digestion of the food product as a rapid, safer albeit qualitative screening method. To evaluate the effectiveness of the Raman procedure in verifying compliance with the European Regulation, the qualitative results obtained using a macro-Raman instrument were compared with those obtained through ICP-based techniques on the same food samples, used as benchmark. In total 22 food-samples belonging to 6 different food categories were analysed. The sampling was conducted in the Italian, Belgian, and French markets both before and after the EU ban on E 171 entered into force. The limit of detection, qualitatively established, was 50 mg kg−1, which effectively encompasses the majority of food items containing E 171, as supported by the extensive literature review. The results obtained with the Raman screening method were found to align well with information reported on product labels and benchmark quantitative data.

Production and characterization of acidophilic xylanase from wood degrading white rot fungus by solid-state fermentation of wheat straw

Xylanases (EC 3.2.1.8) catalyze the breakdown of xylan, which is the second most abundant polysaccharide in plant cell walls. Biological catalysts have gained greater global attention than chemical catalysts in different industrial processes because they are highly selective, easy to control and have a negligible environmental impact. The aim of this study was to investigate the xylanolytic potential of white-rot fungi, optimize their physicochemical conditions and characterize the resulting xylanase. Sixty-eight white-rot fungus (WRF) isolates were screened for their xylanolytic potential and growth conditions for maximal xylanase production using cheap agricultural residue (wheat straw) as the sole carbon source. Five WRF isolates with high xylanase yields (73.63 ± 0.0283–63.6 ± 0.01247 U/ml) were selected by qualitative and quantitative screening methods. The optimum xylanase production occurred at pH 5.0 and 28 °C. Solid-state fermentation (SSF) yielded a high amount of xylanase. The highest xylanase activity (80.9–61.274 U/mL) was recorded in the pH range of 5.0–6.5 and at 50 °C. The metal ions Mg2+, Ca2+ and Mn2+ enhanced the activity of xylanase (127.28–110.06 %), while Cu2+, Fe2+ and K+ inhibited the activity with 43.4–17 % losses. The km and Vmax were 0.32–0.545 mg/mL and 86.95–113.63 μmol/min/mg, respectively. This finding indicates that wheat straw can be used for large-scale xylanase production under SSF conditions. The pH and temperature profiles and stabilities indicate that the xylanase produced in the present study can be applied in food and animal feed industries.

Antioxidant activity of Eucheuma cottonii Seaweed Extracts from Central Mawasangka Waters

Eucheuma cottonii is one type of seaweed that has the potential to be an antioxidant. This seaweed grows and is distributed in various waters of Indonesia, especially in Southeast Sulawesi. However, information regarding the antioxidant activity and the compound content of E. cottonii in this area is still limited. Therefore, this research aims to determine the compound and antioxidant activity profile in E. cottonii. The study used laboratory experimental methods. The research stages were preparation (seaweed sampling), extraction, qualitative phytochemical screening, and antioxidant assay. The initial identification of compounds using qualitative phytochemical screening methods with three extraction solvents: ethanol, ethyl acetate, and n-hexane. Meanwhile, the antioxidant test employed the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. The results of qualitative phytochemical screening revealed that the seaweed extract of E. cottonii contains saponins, tannins, and terpenoids. The antioxidant assay using the DPPH method indicated that among the three extraction solvents used, ethanol extract exhibited a very strong antioxidant activity (with an IC50 of 30,036 ppm), compared to ethyl acetate extract (IC50 of 182,179 ppm) and n-hexane extract (IC50 of 641,454 ppm). This study concluded that E. cottonii seaweed has the potential to be developed as a source of natural antioxidants or raw material for the discovery of antioxidant medicines in the future.

Diagnostic accuracy of Dengue NS1 lateral flow immunoassay in comparison to reverse transcriptase polymerase chain reaction and enzyme linked Immunosorbent Assay

The most widely used invitro diagnostic qualitative screening method for dengue virus infection is the lateral flow immunoassay technique. Testing of dengue non-structural antigen NS1 offers specificity in determining the active infection while testing of IgM and IgG helps in differentiating the primary and secondary dengue infections. The ELISA functions as the golden standard for dengue testing and PCR credits for the most accurate determination tool at the genetic level. The RT-PCR endorsed NS1 gene and in ELISA or LFIA NS1 antigen is used as the marker owing to the specificity and lesser chances of mutation effects. This study evaluated the performance of AG-Q Dengue NS1 LFIA kit in comparison with RT-PCR quantification cycle (Cq) Values and ELISA NS1 quantitation. The study also focused on differentiating the samples among dengue serotypes using the RealStar Dengue Type RT-PCR Kit 1.0. Dengue serotype 2 is the prominent viral strain in Kerala region succeeded by serotype 3 and 1 with a prevalence rate of 64 %, 20 % and 6 % respectively. Dengue serotype 4 was not reported during this study period. 10 % co-infection with DENV 1 & DENV 2 was also reported. The AG-Q Dengue NS1 kit stood as efficient in screening by providing positive results with samples having RT-PCR Cq values up to 43 and ELISA NS1 quantification minimum of 14 Panbio units.

Measurement and analysis of regional water-energy-food nexus resilience with an improved hybrid kernel extreme learning machine model based on a dung beetle optimization algorithm

CONTEXTIn traditional water-energy-food nexus (WEFN) system analysis, the impact of resilience is insufficiently considered, and the accuracy of resilience assessment is low, which can easily lead to system imbalance. Modeling measures can yield optimal evaluation results and provide decision makers with a scientific and efficient basis for management. OBJECTIVEThe objective of this study was to provide a new research paradigm for exploring the sustainable development of WEFN systems by quantitatively and accurately assessing WEFN resilience and identifying its key driving factors. METHODSThe connotation of WEFN resilience was established, and a human-centered conceptual framework for WEFN resilience was constructed. A WEFN resilience evaluation system was scientifically and completely constructed using qualitative and quantitative index screening methods. The hybrid kernel extreme learning machine (HKELM) model was improved based on the dung beetle optimization (DBO) algorithm to measure and analyze the WEFN resilience of the China Beidahuang Group. The CRiteria Importance Through Intercriteria Correlation (CRITIC) method was adopted to calculate the evaluation index weight of the WEFN system of the Beidahuang Group. Model performance verification methods, such as application of the theory of serial number summation, were used to evaluate the performance of the DBO-HKELM model. RESULTS AND CONCLUSIONSThe results showed that over time, the Beidahuang Group's WEFN resilience exhibited a fluctuating upward trend. From 2006 to 2008, WEFN resilience declined to level II because of predatory agricultural production and management practices. From 2008 to 2018, the WEFN resilience increased to level IV due to the protection of uncultivated land, the optimization of irrigation methods, and the increasing maturity of the agricultural modernization development model. Likewise, from 2018 to 2020, the WEFN resilience stabilized at level IV because of the optimization of agricultural planting structures and the reduction in coal consumption. Spatially, the WEFN resilience of various branches of the Beidahuang Group exhibited a trend of “gradually decreasing from north to south.” Differences in certain variables, such as the proportion of area irrigated with electromechanical wells, were the most important factors related to changes in WEFN resilience over time. The DBO-HKELM model has notable advantages over the FA-HKELM and NGO-HKELM models in terms of fitting accuracy, optimization rate, reliability, rationality, and robustness. SIGNIFICANCEThese research results could enrich quantitative assessment methods for determining WEFN system recovery strength and provide scientific support for the safe operation and sustainable development of agricultural economies and societies.

A study of chemical compounds and antimicrobial activities of Vernonia amygdanlina extract from different areas and the age of leaves as animals’ feed additives

Herbal plants have been used as an alternative to replace the use of antibiotics in animal production. African leaves (Vernonia amygdalina) are herbal plants that have medicinal properties. This study was carried out with the purpose of evaluating the biochemical and antimicrobial compounds of African leaf extract as a phytogenic supplement in animal feed. African leaves (V. amygdalina) which grow massively in Aceh were extracted using 96% ethanol solvent in 1:3 ratio. There were 4 African leaf samples differentiated according to young and old leaves that grow in the highlands and lowlands used in this study. Biochemical compound testing was carried out using a qualitative phytochemical screening method and antimicrobial testing (Salmonella and Escherichia coli) using the Kirby Bauer Disc Diffusion method using Salmonella enterica sv Typhimurium ATCC 14028 and E. coli ATCC 25922 bacteria with a Mc Farland standard of 0.5. Phytochemical test results show that African leaves contain alkaloids, steroids, flavonoids and phenolics. Meanwhile, the results of antimicrobial testing did not show inhibition against Salmonella and Escherichia coli bacteria. This research concluded that the extracted leaves of African plants had the potential to be administrated as a phytogenic additional feed.

Screening and confirmation of psilocin, mitragynine, phencyclidine, ketamine and ketamine metabolites by liquid chromatography-tandem mass spectrometry.

A safe and productive workplace requires a sober workforce, free from substances that impair judgment and concentration. Although drug monitoring programs already exist, the scope and loopholes of standard workplace testing panels are well known, allowing other substances to remain a source of risk. Therefore, a high-throughput urine screening method for psilocin, mitragynine, phencyclidine, ketamine, norketamine and dehydronorketamine was developed and validated in conjunction with a urine and blood confirmation method. There are analytical challenges to overcome with psilocin and mitragynine, particularly when it comes to drug stability and unambiguous identification in authentic specimens. Screening and confirmation methods were validated according to the American National Standards Institute/Academy Standards Board (ANSI/ASB) Standard 036, Standard Practices for Method Validation in Forensic Toxicology. An automated liquid handling system equipped with dispersive pipette extraction tips was utilized for preparing screening samples, whereas an offline solid-phase extraction method was used for confirmation sample preparation. Both methods utilized liquid chromatography-tandem mass spectrometry to achieve limits of detection between 1-5 ng/mL for the screening method and 1 ng/mL for the confirmation method. Automation allows for faster throughput and enhanced quality assurance, which improves turnaround time. Compared to previous in-house methods, specimen volumes were substantially decreased for both blood and urine, which is an advantage when volume is limited. This screening technique is well suited for evaluating large numbers of specimens from those employed in safety-sensitive workforce positions. This method can be utilized by workplace drug testing, human performance and postmortem laboratories seeking robust qualitative screening and confirmation methods for analytes that have traditionally been challenging to routinely analyze.

Evaluation of the Phytochemical, Total Phenolic Content, and Antioxidant Activity of Banto Grass (Leersia hexandra) Using an Ecological and Ethnobotanical Approach

Banto (Leersia hexandra) is an essential plant for the Minangkabau people. Banto grass is a weed plant that easily grows anywhere. This plant can live in dry, watery, or damp areas. This study aimed to evaluate the phytochemical and total phenolic content of banto grass using an ecological and ethnobotanical approach. Banto grass samples originate from Lintau Buo and Pariaman. The phytochemical content of banto grass was determined using a qualitative screening method, and the total phenolic content was determined using gallic acid (GAE) standards. The ecological and ethnobotanical aspects of banto are studied through literature studies including information on botany, ecology, distribution, local names and traditional medicine. The results showed that both banto grass from the high and lowlands extracted with methanol had positive results for flavonoids, alkaloids, tannins, saponins and steroids. However, quantitatively, the total phenolic content of highland banto extract has a higher value than lowland, namely 842.593 mg/L and 649.471 mg/L respectively. Based on ethnobotanical aspects, the leaves of Banto have long been used to make a drink which functions to eliminate toxins in the body, asthma, and shortness of breath. Apart from that, our ancestors also used banto leaves as a toothbrush. Banto grows scattered around areas with lots of water, therefore, the Minang people also use banto as an indicator for digging wells.

High-efficient screening of pesticide residues in vegetables using gas chromatography/quadrupole time-of-flight (GC/Q-TOF)

Gas chromatography (GC) and liquid chromatography (LC) coupled with a triple quadrupole mass spectrometer using multiple reaction monitoring (MRM) mode is widely used for pesticide residue analysis. However, MRM mode cannot fulfill the requirements of high-throughput or non-target analysis. High-resolution mass spectrometry such as time-of-flight (TOF) with high mass accuracy enables targeted and non-targeted analysis. This study proposes a qualitative screening method using GC/quadrupole time-of-flight (GC/Q-TOF) to monitor vegetable pesticide residues based on the retention time and accurate mass database of the MassHunter Personal Compound Database and Library (PCDL). GC/Q-TOF screening identified 89 of 92 pesticides in 90 vegetable samples, resulting in a true positive rate of 96.7%. These results were in excellent agreement with those obtained from conventional LC-MS/MS and GC-MS/MS methods (Cohen’s Kappa = 0.82). Thiamethoxam exhibited the highest detection frequency at 13.75% (mostly below the MRL), with imported radishes showing the highest occurrence. Moreover, unexpected pesticides and metabolites, including cinmethylin, benzyl benzoate, 2,6-dichlorobenzamide, diethyltoluamide, and phthalimide, were detected. This proposed method enables qualitative screening of over 1000 pesticides without using expensive analytical standards. Further manual investigation can be conducted to mitigate false-positive results. Overall, this evaluation demonstrates that the combination of GC/Q-TOF with the commercial PCDL database is robust and suitable for pesticide screening in vegetables.

Comprehensive Urine Drug Screen by Liquid Chromatography-Quadrupole Time of Flight Mass Spectrometry.

Current trends in drug use include polydrug use as well as an ever-changing landscape of novel psychoactive substances. Immunoassay-based urine drug screens limited to classic drugs of abuse do not have the scope necessary to identify patients with drug intoxications or drug misuse. Mass spectrometry is an alternative method that is both sensitive and specific. In this chapter, we present a liquid chromatography-quadrupole mass spectrometry-based method for qualitative comprehensive urine drug screening. The method runs in positive mode and encompasses over 1000 basic compounds, including pharmaceutical, illicit, and novel drugs. Retention time, MS and MS/MS spectra, mass error, and isotope confidence are parameters used for compound identification. New compounds are readily added as new recreational drugs emerge.

Phytochemical profiling, pharmacology prediction, and molecular docking study of Chromolaena odorata extract against multiple target proteins in wound healing

Introduction: Wounds have a significant influence on socioeconomic and the quality of life. Many attempts have been taken to produce advanced wound dressing to fulfill demands. The incorporation of natural therapeutics like medicinal plants in wound dressings is currently popular. However, several medications have failed to enter the market due to inadequate pharmacokinetics data. Computer-aided tools are now available as advanced drug discovery methods, which can be used to screen pharmaceuticals from phytochemicals found in various medicinal plants. This study aims to evaluate the phytoconstituents of Chromolaena odorata extract and its pharmacological potential as a wound-healing agent. Methods: Phytoconstituents from C. odorata were identified using qualitative screening methods and gas chromatography-mass spectrometry (GC-MS), and their mechanistic properties were assessed using molecular docking and SwissADME tools. Results: Current works revealed that the topmost phytoconstituents in C. odorata were phytol (49.83%), hexadecanoic acid ethyl ester (9.40%), linolenic acid (8.07%), and squalene (3.53%). Through SwissADME analysis, all four topmost compounds obeyed Lipinski’s Rule of 5. In silico molecular docking study of these top phytoconstituents against several protein targets involved in wound healing revealed that squalene had the highest binding affinity to GSK3-β (-6.8 kJ/ mol), MMP-9 (-7.4 kJ/mol), and COX-2 (-8.6 kJ/mol) as compared to other ligands (phytol, linolenic acid, and hexadecenoic acid ethyl ester). Conclusion: These findings suggest that the most prominent compound that contributes to C. odorata’s wound healing capacity is squalene and the incorporation of C. odorata in potential wound dressing formulation is justified.

Flow-injection MS analysis as a simplified approach to pesticide screening in apples

A fast and simplified method based on mass spectrometry analysis was developed for pesticide qualification in apple peel. The main feature of the method is flow-injection of the loop pre-defined sample volume directly to the MS source, with no chromatographic separation. Method performances were evaluated for five pesticides regularly used in apple orchard treatments. First, primary features of the method such as the loop injection dynamics, total analysis time, chronogramic peaks integrity and sensitivity were evaluated. Then the applicability of the method for qualitative and quantitative screening was assessed on citrate buffered QuEChERS cleaned-up apple peel samples. The developed method offers a possibility for simplified, more economic high throughput screening for pesticides in apples. The method is intended to be a tool for preliminary qualitative assessment of pesticides residues in fruit. Quantitative features of the method are analyte and sample preparation dependent, most certainly due to the lack of chromatography.

Phytochemical Screening, GC-MS Analysis of Methanolic Extract of the Fern Adiantum Caudatum from Southern Western Ghats

The present study was to screen the presence of phytochemicals in the methanol extract of fern Adiantum caudatum species by composed with qualitative and quantitative screening methods. In qualitative analysis, the presence of pharmacologically active phytochemicals such as alkaloids, flavonoids, glycosides, steroids, tannins, terpenoids, saponins, phenols, volatile oils and resins were screened. GC-MS chromatogram analysis of the methanolic extract of Adiantum caudatum showed 12 peaks corresponding to 12 different compounds. The percentage of major bioactive compounds were 2-Hydroxymethyl-9-[Beta.-D-Ribofuranosyl] Hypoxanthine (17.995%), 2-Undecene,5-methyl- (33.497%), Pentadecane,2,6,10,14-Tetramethyl- (14.977%), Nonadecane (7.588%), Dodecane, 2,6,10-trimethyl- (1.421%), 3,7,11,15-Tetramethyl-2-Hexadecen-1-ol (2.825%), Nonadecane (7.855%). The identification of bioactive compounds is based on the retention time, peak area, molecular formula, and probability.

DIVERISTY and enzymatic potential of indigenous bacteria from unexplored contaminted soils in Faisalabad

Bacteria residing in contaminated waste soil degrade and utilize organic and inorganic material as a source of nutrients as well as reduce environmental contamination through their enzymatic machinery. This enzymatic potential of indigenous bacteria can be exploited at industrial level through detailed screening, characterization, optimization and purification. In present study, diversity and enzymatic potential of indigenous bacteria was investigated through qualitative and quantitative screening methods from unexplored contaminated soil waste sites in Faisalabad. Shannon diversity (H’) index revealed that twenty-eight soil samples from four contaminated sites were highly diverse of amylase, protease and lipase producing bacteria. Maximum protease producing bacteria were detected in fruit waste (1.929 × 107), whereas amylase and lipase producing bacteria were found in industrial (1.475 × 107) and (5.38 × 106), in household waste soil samples. Most of the indigenous bacterial isolates showed potential for multiple enzymes. An isolate OC5 exhibited capability for amylase production and optimization at a wider range of cultural conditions; pH (6–8), temperature (25 °C, 37 °C, 45 °C), incubation time (24–72 h), and NaCl concentrations 0.5–13%, using (1%) starch and lactose as substrates. An isolate OC5 was identified by molecular identification and phylogenetic analysis showed 99% sequence similarity with Bacillus spp. ANOVA was used to analyzed all data statistically. This study enhances the importance of initial screening and reporting of industrially potent indigenous bacteria from unexplored contaminated waste soils. In future, indigenous bacteria in contaminated wastes may be good candidates to solve various environmental pollution problems.

Isolation and Characterization of Biosurfactant Producing Pseudomonas aeruginosa YLA03 and its Diesel Degradation Potentials

This work was aimed at isolating and characterising biosurfactant producing bacteria strain from diesel oil contamination sites. The potential of the strain to degrade diesel oil n-alkanes was further studied. Soil samples were collected from diesel rich areas, and identified strains were grown on minimal media that contained diesel oil as only carbon source. Enrichment culture technique was used to identify bacteria. Seventeen bacteria strains were identified based on their capacity to use diesel oil as carbon source. Other qualitative screening methods were employed to determine the potential to produce biosurfactants. Isolate A03 was the only candidate that shows positive signs for drop collapse, foaming, haemolytic, oil displacement and emulsification tests. The effect of various culture parameters (incubation time, concentration of diesel, nitrogen source, pH and temperature) on biodegradation of diesel was evaluated. Optimum pH was 8.0 at 35° C, while the incubation time at maximum bacteria growth was five (5) days. The favourable diesel oil concentration was 7.5% for the isolate. The isolate has shown degradative ability towards dodecane, Tridecane, tetradecane but was unable to degrade 2, 6, 10-trimethyl- dodecane. It degraded between 10.09% - 45.39% of individual diesel alkanes. The strain has exhibited potential for degrading diesel alkanes and was identified as pseudomonas aeruginosa strain A3 (Accession Number: MZ027605) using the 16S rRNA. Sequencing.

Screening for cellulases and preliminary optimisation of glucose tolerant β-glucosidase production and characterisation

ABSTRACT The search for a novel microbial producer of cellulases including a glucose tolerant β-glucosidase is a challenge as most are inhibited by their product glucose. This study aims to screen for cellulolytic fungi using qualitative and quantitative screening methods. Primary screening revealed 34 of 46 fungal isolates with β-glucosidase activity. Eleven and 13 of these also displayed endoglucanase and exoglucanase activities, respectively. During secondary screening, this number was reduced to 26 β-glucosidase producers with 13 also having endoglucanase and exoglucanase activities. Isolate C1 displayed enhanced production of β-glucosidases in the presence of 0.05 M glucose (69% higher activity). Optimisation of growth conditions for β-glucosidase production by one variable at a time experiments improved production for (isolates) PS1 (64%), MB5 (84%), and C2 (69%). Isolate PS1 identified as Chaetomella sp. BBA70074 displayed the highest tolerance to glucose, retaining 10% of β-glucosidase activity in the presence of 0.8 M glucose. Tolerance to glucose increased to 14% when produced under optimal conditions. β-Glucosidase had a molecular weight of 170 kDa with a pH and temperature optima of 6 and 70 °C, respectively. Future studies will include optimisation of the production of the glucose tolerant enzyme by Chaetomella sp. BBA70074.

Differential Kendrick's Plots as an Innovative Tool for Lipidomics in Complex Samples: Comparison of Liquid Chromatography and Infusion-Based Methods to Sample Differential Study.

Lipidomics has developed rapidly over the past decade. Nontargeted lipidomics from biological samples remains a challenge due to the high structural diversity, the concentration range of lipids, and the complexity of biological samples. We introduce here the use of differential Kendrick's plots as a rapid visualization tool for a qualitative nontargeted analysis of lipids categories and classes from data generated by either liquid chromatography-mass spectrometry (LC-MS) or direct infusion (nESI-MS). Each lipid class is easily identified by comparison with the theoretical Kendrick plot pattern constructed from exact mass measurements and by using MSKendrickFilter, an in-house Python software. The lipids are identified with the LIPID MAPS database. In addition, in LC-MS, the software based on the Kendrick plots returns the retention time from all the lipids belonging to the same series. Lipid extracts from a yeast (Saccharomyces cerevisiae) are used as a model. An on/off case comparing Kendrick plots from two cell lines (prostate cancer cell lines treated or not with a DGAT2 inhibition) clearly shows the effect of the inhibition. Our study demonstrates the good performance of direct infusion as a fast qualitative screening method as well as for the analysis of chromatograms. A fast screening semiquantitative approach is also possible, while the targeted mode remains the golden standard for precise quantitative analysis.