Bioassay Research Articles

Comparative Bio Assay of New Generation Insecticides against Invasive Southeast Asian Thrips, Thrips parvispinus (Karny) (Thripidae:Thysanoptera)

Aims: Management of invasive southeast Asian thrips, Thrips parvispinus under laboratory conditions. Study Design: Completely Randomized Design. Place and Duration of Study: Regional Agricultural Research Station, Guntur, Andhra Pradesh during 2023. Methodology: Bio assays study was conducted with eleven insecticides for the Management of Thrips parvispinus under laboratory conditions following leaf dip method replicated thrice. Mortality and corrected mortality were assessed at 24 and 48 hours after treatment imposition by counting the number of dead and live adults. Results: Bio assay study revealed that the insecticide broflanilide 300 DC @ 64.0 ml/ha recorded significant high percent mortality of 93.3 at 48 hours after exposure. The insecticides fluxametamide 10 EC @ 400 ml/ha, tolfenpyrad 15 EC@ 1000 ml/ha, spinoterom 11.7 SC @ 500 ml/ ha and fipronil 5 SC @1000 ml/ha were at par with broflanilide 300 DC with 90.0, 90.0, 86.7 and 86.7 percent mortality, respectively. Lowest mortality of 6.0 percent was observed in untreated control where the leaves were agitated in distilled water. The corrected mortality was calculated and the insecticides broflanilide 300 DC (92.59 %), fluxametamide 10 EC (88.9), tolfenpyrad 15 EC (89.3), spinetoram 11.7 SC (85.9) and fipronil 5 SC @400 ml/acre (85.2) recorded high corrected mortality at 48 hours of post treatment.

Solutal Marangoni augmented levitation time of an aqueous surfactant drop over an immiscible oil pool

Droplets are found to exhibit a finite residence time over the volatile liquid pool due to the confined evaporation mediated sustained thin film draining. The levitated drops are quite critical in biomedical applications such as for the biophysical micro reactors. It is hypothesized that the presence of surfactants can induce solutal Marangoni and can further enhance the levitation time. Moreover, the surfactant drops can closely mimic the bio drop assay. Droplets of surfactant solutions are allowed to impact over a series of volatile hydrocarbon oils to understand the effect of surfactant concentration, impact height and the properties of the oil pool using high speed imaging technique. Flow visualization is employed in the pendant droplet mode to understand the Marangoni induced internal circulation. The droplets of surfactant solutions are found to exhibit enhanced residence time compared to the case of non-surfactant drops. The levitation time is a function of the surfactant concentration and the volatility of the oil pool. A mathematical model is developed incorporating the effect of solutal Marangoni to test the hypothesis and is found to predict the levitation time with reasonable accuracy. A universal floating–sinking regime map was developed incorporating the influence of governing parameters.

PERSIAN traffic safety and health cohort: a population-based precrash cohort study

PurposeDespite to high burden of road traffic injuries (RTIs), the RTI epidemiology has received less attention with rare investments on robust population cohorts. The PERSIAN Traffic Safety and Health Cohort...

Revolutionizing sample preparation: a novel autonomous microfluidic platform for serial dilution.

Dilution is a standard fluid operation widely employed in the sample preparation process of many bio(chemical) assays. It serves multiple essential functions such as sample mixing with certain reagents at specific dilution ratios, reducing sample matrix effects, bringing target analytes within the linear assay detection range, among many others. Traditionally, sample processing is performed in laboratory settings through manual or automated pipetting. When working in resource-limited settings, however, neither trained personnel nor proper laboratory equipment are available limiting the accessibility to high-quality diagnostic tests. In this work, we present a novel standalone and fully automated microfluidic platform for the stepwise preparation of serial dilutions without the need for any active elements. Stepwise dilution is achieved using the coordinated burst action of hydrophobic burst valves to first isolate a precisely metered volume from an applied sample drop and subsequently merge it with a prefilled diluent liquid. Downstream, expansion chambers are used to mix both reagents into a homogeneous solution. The dilution module was characterized to generate accurate and reproducible (CV < 7%) dilutions for targeted dilution factors of 2, 5 and 10×, respectively. Three dilution modules were coupled in series to generate three-fold logarithmic (log5 or log10) dilutions, with excellent linearity (R2 > 0.99). Its compatibility with whole blood was furthermore illustrated, proving its applicability for automating and downscaling bioassays with complex biological matrices. Finally, autonomous on-chip serial dilution was demonstrated by incorporating the self-powered (i)SIMPLE technology as a passive driving source for liquid manipulation. We believe that the simplicity and modularity of the presented autonomous dilution platform are of interest to many point-of-care applications in which sample dilution and reagent mixing are of importance.

Identification of maturation-inducing steroid in sturgeons via comprehensive analyses of steroids produced during oocyte maturation

Although 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) and 17α, 20β, 21-trihydroxy-4-pregnen-3-one (20β-S) have been identified as maturation-inducing steroids (MIS) in several teleosts, to date, no MISs have been identified in sturgeons. As it remains possible that an unidentified steroid is an MIS in sturgeons, this study aimed to identify a sturgeon MIS via comprehensive analyses and maturation-inducing (MI) assay of C21 steroids. In vivo and in vitro comprehensive analyses of C21 steroids revealed that serum DHP concentrations were rapidly elevated in the oocyte maturation phase and the DHP production level was notably high among C21 steroids. MI assay indicated that the MI activity of DHP, 17α-hydroxyprogesterone (17OHP), a precursor of DHP, 17α, 20α-dihydroxy-4-pregnen-3-one (αDHP), and 20β-S was high among C21 steroids, but the MI activity of these steroids were similar. In the C21 steroids produced in ovarian follicles during oocyte maturation, 17OHP, αDHP, and unidentified compounds had a low production level, and 20β-S was suggested to be metabolized from DHP after oocyte maturation. Against this background, this study concluded that DHP is a steroid that possesses strong MI activity and is highly produced during oocyte maturation. Although this study could not identify an MIS in sturgeons by fractionation of plasma and subsequent bio assay, it was suggested that DHP is a major MIS in sturgeons.

Bioactivity profiles of six baobab fruit pulp powders via planar chromatography hyphenated with effect-directed analysis

Baobab (Adansonia digitata) fruit pulp has a high nutrient content and has been traditionally used for medicinal purposes (e.g., as an anti-inflammatory and antioxidant agent) that may help protect against chronic diseases. Six different baobab fruit pulp powders were investigated using three different extractants and analyzed by high-performance thin-layer chromatography (HPTLC) hyphenated with antibacterial bioassays and enzyme inhibition assays. The developed non-target effect-directed screening was performed after extraction with pentyl acetate – ethanol 1:1 (V/V) on the HPTLC plate silica gel 60 using toluene – ethyl acetate – methanol 6:3:1 (V/V/V) as mobile phase system and derivatization via the anisaldehyde sulfuric acid reagent for detection. The physico-chemical profiles of the six baobab fruit pulp powder extracts were comparable, although the intensity of some zones was moderately different. The following effect-directed profiling via tyrosinase, α-glucosidase, and acetylcholinesterase inhibition assays as well as antibacterial Aliivibrio fischeri and Bacillus subtilis bioassays revealed one prominent multipotent bioactive compound zone in common, more or less active in all five studied (bio)assays. Via the recording of high-resolution mass spectra, this compound zone was tentatively assigned to coeluting saturated (palmitic acid 16:0 and stearic acid 18:0), monounsaturated (oleic acid 18:1), and polyunsaturated (linoleic acid 18:2 and linolenic acid 18:3) fatty acids. This finding was confirmed by other studies, which already proved individual activities of fatty acids. The first (bio)activity profiling of baobab fruit pulp powders via HPTLC-effect-directed analysis revealed that the baobab fruit could be considered as a functional food, however, further research is needed to study the impact on health and the influences on the bioactivity arising from different climates, years and soils or regions.

Bioactivity Profiling and Quantification of Gastrodin in Gastrodia elata Cultivated in the Field versus Facility via Hyphenated High-Performance Thin-Layer Chromatography.

Gastrodia elata (Orchidaceae) is native to mountainous areas of Asia and is a plant species used in traditional medicine for more than two thousand years. The species was reported to have many biological activities, such as neuroprotective, antioxidant, and anti-inflammatory activity. After many years of extensive exploitation from the wild, the plant was added to lists of endangered species. Since its desired cultivation is considered difficult, innovative cultivation methods that can reduce the costs of using new soil in each cycle and at the same time avoid contamination with pathogens and chemicals are urgently needed on large scale. In this work, five G. elata samples cultivated in a facility utilizing electron beam-treated soil were compared to two samples grown in the field concerning their chemical composition and bioactivity. Using hyphenated high-performance thin-layer chromatography (HPTLC) and multi-imaging (UV/Vis/FLD, also after derivatization), the chemical marker compound gastrodin was quantified in the seven G. elata rhizome/tuber samples, which showed differences in their contents between facility and field samples and between samples collected during different seasons. Parishin E was also found to be present. Combining HPTLC with on-surface (bio)assays, the antioxidant activity and inhibition of acetylcholinesterase as well as the absence of cytotoxicity against human cells were demonstrated and compared between samples.

Clinical application of Mycobacterium RT-PCR assay using various specimens for the rapid detection of lymph node tuberculosis: A diagnostic accuracy study.

To evaluate the diagnostic accuracy of the Capital Bio Mycobacterium real-time polymerase chain reaction assay Capital Bio assay for lymph node (LN) tuberculosis (LNTB), and to further compare the effect of different types of LN specimens on the detection capability of the test. We retrospectively analyzed the medical records of LNTB patients who met the inclusion criteria. The sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve of Capital Bio assay were calculated to evaluate its diagnostic accuracy compared with the final clinical diagnosis as reference standard. Three hundred sixty-four patients were included in the study. The overall sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve of the Capital Bio assay for LNTB were 74.4%, 100.0%, 100.0%, 34.9%, and 0.87, respectively. For the pus specimens, these values for Capital Bio assay were 93.2%, 100.0%, 100.0%, 27.3%, 0.97, respectively. For the core needle biopsy specimens, these values were 65.9%, 100.0%, 100.0%, 33.3%, and 0.83, respectively. For the fine-needle aspiration specimens, these values were 60.0%, 100.0%, 100.0%, 53.9%, and 0.80, respectively. For the tissue, these values were 59.3%, 100.0%, 100.0%, 33.3%, 0.80, respectively. The Capital Bio assay had good effective for the diagnosis of LNTB. Compared to LN fine-needle aspiration and core needle biopsy specimens and tissue specimens, pus specimens were more suitable for molecular testing and had the best diagnostic efficacy.

4-Methylumbelliferone Targets Revealed by Public Data Analysis and Liver Transcriptome Sequencing.

4-methylumbelliferone (4MU) is a well-known hyaluronic acid synthesis inhibitor and an approved drug for the treatment of cholestasis. In animal models, 4MU decreases inflammation, reduces fibrosis, and lowers body weight, serum cholesterol, and insulin resistance. It also inhibits tumor progression and metastasis. The broad spectrum of effects suggests multiple and yet unknown targets of 4MU. Aiming at 4MU target deconvolution, we have analyzed publicly available data bases, including: 1. Small molecule library Bio Assay screening (PubChemBioAssay); 2. GO pathway databases screening; 3. Protein Atlas Database. We also performed comparative liver transcriptome analysis of mice on normal diet and mice fed with 4MU for two weeks. Potential targets of 4MU public data base analysis fall into two big groups, enzymes and transcription factors (TFs), including 13 members of the nuclear receptor superfamily regulating lipid and carbohydrate metabolism. Transcriptome analysis revealed changes in the expression of genes involved in bile acid metabolism, gluconeogenesis, and immune response. It was found that 4MU feeding decreased the accumulation of the glycogen granules in the liver. Thus, 4MU has multiple targets and can regulate cell metabolism by modulating signaling via nuclear receptors.

Testing the susceptibility of larval stages of Simulium to temephos and Bacillus thuringiensis var israelensis in Germany and Northern Cameroon.

Assays to evaluate the susceptibility of Simulium larvae to temephos and Bacillus thuringiensis var israelensis (Bti) were carried out by setting-up an in vitro laboratory test ('bio assay') and a semi-natural test ('système de goutières') to assess the LC50/LC90 values. Larvae of Simulium species in Cameroon (S. damnosum s.l., S. hargreavesi, S. vorax and S. cervicornutum) and (S. (Odagmia) ornatum and S. latipes) in Germany were identified and tested. In the bio-assay, 50 larvae were exposed for 10min to concentrations from 0.01 to 10ppm. For the Simulium from Germany, the LC50 (LC90) values after 3 and 6h were 3.1 (27.9) and 0.14 (1.26) ppm for temephos and for Bti 7.8 (70.2) and 1.7 (15.3) ppm, respectively. For Cameroonian species, the values of LC50 (LC90) were lower, that is, 0.42 (8.04), 0.14 (2.70) and 0.073 (1.38) ppm, respectively, after 3, 6 and 12 h for temephos. In a semi natural condition, the LC50 of 10min of application of temephos was 0.84 ppm after 3h and a working solution (2.6 L) of Bti killed 50% after 6h. To detect an upcoming of any resistance as it happened in Ivory Coast, a study of the occurrence resistance genes should be implemented.

Assay of Trace Copper Ion in Water Resources Using a Photo-sensing Diode Circuit

Background: Trace copper play an important role in plant growth and is a biological component of various enzymes involved in both photosynthesis and plant respiration, in this study. Objective: Electrochemical voltammetric bio assay of trace copper ion was detected by using photo-sensing diode circuits (PSD) with a working sensors for ppb levels trace detection in agricultural water by stripping and cyclic voltammetry. Results: Optimum voltammetric conditions were examined. The system used was simple and inexpensive circuits of our fabricated systems, but low detection limit was attained at 40.0 ugL⁻¹. Here can be attained to low detection limits better then common diagnostic analyzers. Conclusion: The developed technique can be used in determining trace amounts of copper, especially in detecting copper ions in agricultural water resources.

Silver Nanoparticle Labels for Electrochemical Detection of Bioassays

Electrochemistry plays a major role in immunosensor development because of its higher sensitivity, simplicity, portability, and rapidity compared to more common enzymatic, fluorescent and radioactive labelling methods. Silver nanoparticles (AgNPs) have been identified as potential electrochemical labels for such immunoassays. Characterizing the composition, size, shape, and surface modifications of the AgNP is important to achieve expected analytical performance of the bio assay. Here we are interested in studying the effect of nanoparticle shape towards the electrochemical detection of a metallo-immunoassay using Au-Ag galvanic exchange (GE) reaction followed by anodic stripping voltammetry. We observe that during GE between electrogenerated Au3+ and the Ag labels, a thin shell of Au forms on the surface of the NP and prevent further exchange. This shell is more porous when GE proceeds on silver nanocubes (AgNCs) compared to spherical silver nanoparticles (sAgNPs), and therefore, more exchange occurs when using AgNCs. More interestingly, optimizing the ratio of the two types of AgNP labels, we could able to decrease the LOD of a biological assay designed to detect a heart failure biomarker (NT-proBNP) without compromising the dynamic range compared to using either of the two labels independently. This made it possible to achieve the clinically relevant range for NT-proBNP analysis used by physicians for heart failure risk stratification.

CORRELATION OF SERUM GALECTIN-3 LEVELS WITH EJECTION FRACTIONS IN HEALTHY SUBJECTS AND HEART FAILURE PATIENTS

Background: High Galectin-3 levels are indicative of severity of heart diseases and are associated with increased risk of major adverse cardiovascular events including heart failure. The objective of this study was to determine correlation between ejection fraction and serum Galectin-3 levels recorded by simple and quick test. Methods: This cross-sectional analytical study was conducted at the Armed Forces Institute of Cardiology (AFIC) Rawalpindi. Thirty (30) healthy adults and 60 heart failure patients were selected through randomised sampling. Diagnosed cases were classified using modified NYHA classification. Group 1 included healthy adults, Group 2 included 30 mild heart failure subjects of NYHA class I and II, Group 3 included 30 severe heart failure subjects of NYHA class III and IV. Ejection fraction was recorded at AFIC with trans-thoracic echocardiography in supine and left lateral positions. Blood samples of the participants were used for estimation of Galectin-3 by ELISA using human serum Galectin-3 ELISA kit Catalogue No. E1951Hu (Bio Assay technology). Observations were recorded on proforma, Pearson’s correlation test and ANOVA were performed using SPSS-24. Results: The LVEF was 70.7±2.78% in Group-1, 59.3±3.4% in Group-2, and 38.96±12.27% in Group-3. The LVEF showed a substantial negative correlation with serum Galectin-3 levels (r= -0.630, p&lt;0.001). Conclusion: There is a significant negative correlation between Serum Galectin-3 and extent of functional changes of left ventricle recorded by Ejection fraction on echocardiography. Pak J Physiol 2022;18(2):28–30

​Biotin Inhibitors, Avidin and Streptavidin: Their Influence on Lethality, Growth and Survival of Callasobruchus maculatus (Chrysomelidae: Coleoptera)

Background: C. maculatus, the most important and cosmopolitan pest, severely attacking several stored pulses leading to weight loss, market value, as well as the germination potential of the infested grains. The present study was conducted to know the effect of biotin inhibitors, avidin and streptavidin on lethality, growth and survival of Callasobruchus maculatus. Methods: The experiment was conducted in the laboratory of Department of Entomology, Agricultural College, Bapatla during 2017-18. Bio assays were conducted against C. maculatus with biotin binding proteins’ (BBP’s) viz., avidin and streptavidin in comparison with spinosad by pellet feeding method. Similarly the effect of BBP’s on growth development of C. maculatus was also studied. Result: Based on bioassay studies, the LC50 for avidin and streptavidin were 14.733 and 11.192 ppm while LC90 was 76.031 and 86.134 ppm, respectively. The growth and development of C. maculatus was studied at approximately the respective LC25, LC50, LC75, LC80 and LC90 values of avidin and streptavidin. Avidin and streptavidin incorporated pellets when fed to it, avidin at concentration of ≥ 75 ppm was found effective by recording lesser number of eggs (≤ 9 eggs), delayed day of first adult emergence (≥ 53 days), maximum development period ( greater than 68 days), minimum adult emergence (≤ 13%), lower growth index (≤ 0.2) and minimum weight loss (≤ 16%) and streptavidin at concentrations of ≥ 75 ppm recorded comparatively minimum eggs (≤ 7 eggs), prolonged day of first adult emergence (≥ 66 days), maximum development period (≥ 82 days), minimum adult emergence (≤ 13%), lower growth index of ≤ 0.16 and minimum pellet weight loss of ≤ 12% respectively.

Seasonal variation of the effect of extremely diluted agitated gibberellic acid (10-30) on wheat stalk growth - a multi researcher study

Control experiments were performed at different seasons of the year as a follow-up to pilot experiments [1] where a homeopathic high dilution of gibberellic acid had influenced growth in a wheat bio assay (7 days). Grains of winter wheat (Triticum aestivum, Capo variety) were observed under the influence of extremely diluted gibberellic acid (10-30) prepared by stepwise dilution and agitation according to a protocol derived from homeopathy (“G30x”). Analogously prepared water was used for control (“W30x”). Following up on 5 pilot experiments (4 in autumn 2007, 1 in spring 2008), 10 experiments were performed (5 in autumn 2008 or 2009 and 5 in winter 2009 or 2010) with a total of 9 experiments in autumn season (5 researchers, about 9,000 grains), and 6 in winter/spring (4 researchers, about 6,000 grains).&#x0D; Germination rates after 7 days were slightly higher for the autumn experiments (96.1%) than for the winter/spring experiments (94.8%) (p &gt; 0,05), with a non significant trend of more seedlings having germinated in the verum group in the autumn experiments (p &gt; 0,05). All of the 9 autumn experiments (i.e. pilot as well as repetition experiments) showed less stalk growth in the verum group (statistically significant with p &lt; 0.01 in 4, with p &lt; 0.05 in 3 cases, trend in 2 cases). Mean stalk lengths (mm) were 46.97 + 20.50 for the verum group and 50.66 + 19.77 for control (mean + S.D.) at grain level (N = 4,440 per group) and + 3.87 and + 3.38 (+ S.D.) respectively at dish level (217 cohorts of 20 or 25 grains per treatment group). In other words, verum stalk length (92.72%) was 7.28% smaller than control stalk length (100%). The effect size (D means : S.D.), calculated on the basis of dishes, was high (d = 1.02). In contrast, no reliable effect was found in experiments performed in winter/spring (less stalk growth in the verum group in one case, no difference in 2 cases, and more growth in 3 cases). Overall verum stalk length (103.64%) was slightly greater than control stalk length (100%). The effect size, however, was small (d = 0.45). The new data are in line with the 2007 findings, i.e. confirm that gibberellic acid 30x does influence stalk growth.

Seasonal variation of the effect of extremely diluted agitated gibberellic acid (10-30) on wheat seedling development

Objective: Performing a study on a wheat growth bio assay with a homeopathic dilution of gibberellic acid at different seasons of the year.&#x0D; Methods: Grains of winter wheat (Triticum aestivum, Capo variety) were observed under the influence of extremely diluted gibberellic acid (10-30, 30x). Analogously prepared water was used for control. 15 experiments were performed, 9 in autumn season (5 researchers, 4,440 grains per group), and 6 in winter / spring (4 researchers, with 3,140 grains per group).&#x0D; Results: All 9 autumn experiments showed less stalk growth in the verum group (p &gt; 0.01 in 4 cases, p &gt; 0.05 in 3, trend in 2 cases). Mean stalk lengths (mm) were 46.97 + 20.50 for verum and 50.66 + 19.77 for control at grain level (N = 4,440 per group) and + 3.87 and + 3.38 respectively at dish level (217 cohorts of 20 or 25 grains per treatment group). Verum stalk length (92.72%) was 7.28% smaller than control stalk length (100%). In contrast, no reliable effect was found in experiments performed in winter / spring (less stalk growth in 1 case, no difference in 1, more growth in 3 cases). Overall verum stalk length (103.64%) was 3.64% slightly greater than control stalk length (100%). Data were found to be homogeneous within the control groups as well as within the verum groups.&#x0D; Conclusion: Results suggest that especially in the experiments performed in autumn, there was an influence of gibberellic acid 30x on wheat seedling development. The effect size is small when calculation is done on the basis of grains (d = 0.18) but high when done on the basis of dishes (d = 1.02). In contrast, no reliable effect was found in experiments performed in winter / spring. Further experiments should thus be performed in the autumn season.

Pharmacological properties and preliminary phytochemical analysis of Pseudocaryopteris foetida (D.Don) P.D. Cantino leaves

Medicinal plants have significant contribution in pharmaceutical industries being producers of compounds utilized as precursors for drug development. A plant of Lamiaceae family; Pseudocaryopteris foetida had not been investigated for its biomedical potential. Current research was aimed to investigate phytochemical analysis, cytotoxic potential and antioxidant activity of crude methanolic extract and fractions of Pseudocaryopteris foetida (leaves). The preliminary phytochemical analysis of crude methanolic extracts and fractions of Pseudocaryopteris foetida revealed that plant is rich in phenolic and flavonoid classes of secondary metabolites while presence of tannin was observed only in crude methanolic extract. The cytotoxicity was determined using brine shrimp lethality test. Different concentrations (25, 50, 100, 150, 200 and 250 µg/mL) of crude methanolic extract and fractions exhibited dose dependent cytotoxicity. However, The LD50 for all the extracts was more than 200 µg/mL indicating weak cytotoxic potential of Pseudocaryopteris foetida. The antioxidant capabilities of crude methanolic extract and fraction of Pseudocaryopteris foetida were analyzed by in vitro bio assays including DPPH, ABTS, Reducing power and phosphomolybdate antioxidant assays using ascorbic acid as standard. The crude methanolic extract showed IC50 (256.38 ± 0.6 and 314.95 ± 1.1 µg/mL) for DPPH and ABTS respectively, while total antioxidant capacity was calculated as 55.79 ± 0.5 µg/mL for crude methanolic extract of Pseudocaryopteris foetida while ascorbic acid indicated total antioxidant capacity of 71.89 ± 2.3 µg/mL. Study concluded that leaves of Pseudocaryopteris foetida were the rich source of antioxidant phytochemicals. Based on preliminary investigations further research should be focused to isolate bioactive phytochemicals as leading source of clinical medicines in future.

Evaluation of the probiotic potential of Streptomyces antibioticus and Bacillus cereus on growth performance of freshwater catfish Heteropneustes fossilis

Application of probiotics in aquaculture helps to improve the survivability, growth and immunity of aquatic organism in sustainable aquaculture practices. This study was conducted to evaluate the probiotic potentiality of Streptomyces antibioticus EW1 and Bacillus cereus EW5 isolated from the digestive tract of earthworm (Eisenia fetida) and also determine their effects as probiotic in juvenile catfish (Heteropneustes fossilis). The bio safety assay confirmed that the isolates were not pathogenic to the host fish. These strains were able to survive in acidic as well as alkaline conditions, higher tolerance to bile salt as well as gastric juice and high surface hydrophobicity to solvents and displayed extracellular enzyme activity and moreover susceptibility to various antibiotics. Their antimicrobial activity was assessed against two fish pathogens: Aeromonas veronii (MN602971) and Stenotrophomonas maltophilia (MN602972). Among two isolates, the EW1 confirmed good antimicrobial activity against fish pathogens. The isolated bacterial strains were identified and established on the basis of their colony morphology, biochemical characteristics and 16S rRNA sequencing which revealed that the isolates exhibited 99 % sequence homology with Streptomyces antibioticus EW1 (MH301104) and Bacillus cereus EW5 (MH301102). A 45-day feeding trial was conducted to examine the effect of probiotic inoculated fish diet for the freshwater catfish Heteropneustes fossilis. Among three isonitrogenous (30 % CP) diets: RD (reference diet), T1 (diet with Streptomyces antibioticus) and T2 (diet with Bacillus cereus), fish fed T1 diet showed significantly higher growth, digestibility and higher values of crude protein and lipid than fishes reared with T2 and RD. The result of present study suggest that diet supplemented with Streptomyces antibioticus (T1) can be perform as safe probiotic and alternative protein source in the formulation of diet for H. fossilis.

Tolerancia de plantas de zonas áridas a metales pesados

En México las zonas áridas representan más de la mitad del territorio, en estos lugares existe erosión debido a la contaminación, por lo que es importante estudiar el nivel de tolerancia de las especies vegetales representativas para restaurar o reforestar. Se evaluaron seis especies de zonas áridas Agave funkiana, A. obscura, A. salmiana de la familia Asparagaceae y Opuntia cochenillifera, O. f icus-indica, Pereskia sacharosa, de la familia Cactaceae. Se propagaron in vitro para la obtención de brotes que fueron establecidos a diferentes concentraciones de cadmio (Cd2+) y plomo (Pb2+) durante la etapa de enraizamiento para determinar su tolerancia. Se utilizó el método Probit para calcular la concentración letal media (CL50) de las seis especies a las diferentes dosis. Las diferentes concentraciones de Cd y Pb, produjeron distintos efectos en las seis especies de plantas de zonas áridas evaluadas en esta investigación. A. salmiana y P. sacharosa obtuvieron una mortalidad de 55% con 0.009 mM de Cd y una mortalidad de 77% con 0.8 mM para Pb, siendo estas concentraciones las más altas. Los bioensayos ecotoxicológicos son útiles para evaluar contaminantes como los metales pesados en plantas tolerantes como A. obscura, O. cochenillifera y O. f icus-indica.

NEW 1,3,4-OXADIAZOLE BASED SCHIFF BASE DERIVATIVES: SYNTHESIS, CHARACTERIZATION AND ANTIBACTERIAL ACTIVITY ALONG WITH IN SILICO STUDIES

A series of novel 1,3,4-oxadiazole based Schiff base derivatives were designed and synthesized using the efficient strategy with excellent yields. Synthesized molecules evaluated in vitro antibacterial studies in contradiction of microorganisms, namely Escherichia coli , Klebsiella pneumoniae, Bacillus subtilis , and Bacillus megaterium . The bioassay result revealed that most of tested compounds good to moderate inhibition against microorganisms. Some among them show excellent inhibitory effects towards the Gram-positive and Gram-negative bacteria. Besides, the drug-likeness, lipophilicity and cytotoxicity.