Efficacy of Citrullus colocynthis seed extract on Earias vittella, Fabricius, (Lepidoptera: Noctuidae): environment sustainable approach

Earias vittellaFabricius, 1794 (Noctuidae: Lepidoptera) is deliberated to be one of the most destructive pests of cotton and okra vegetation in the world including Asia. The pest has established resistance to various synthetic insecticides. The use of bio-pesticide is one of the unconventional approaches to develop a vigorous ecosystem without harming non- target pests and beneficial natural insect fauna. In the present study, the toxicity levels of Citrullus colocynthis seed extract have been evaluated against the populations of E. vittellaunder standardized laboratory conditions. The toxic effects of C. colocynthis on development periods, protein contents and esterase activity of the life stages of E. vittella were also evaluated. The toxicity levels of methanol, ethanol, hexane, water and profenofos were evaluated on the 1st instar larvae of E. vittella. LC30 and LC80 concentrations exhibited the effectiveness of methanol-based C. colocynthis seed extract against 1st instar larvae of E. vitella. The enhanced larval and pupal periods were revealed in treated samples during the comparison with untreated samples. The intrinsic rate of increase, net reproductive rate in the LC30 and LC80 concentrations exposed larvae remained less than the control treatment. Fecundity, the esterase activity and protein contents were declined in LC30 and LC80 treated samples as compared to the control. The present findings suggest that C. colosynthis extracts based botanical insecticides are beneficial, ecosystem sustainable and can be integrated with insect management programs from environment safety perspective.

Association between human paraoxonase 2 protein and efficacy of acetylcholinesterase inhibiting drugs used against Alzheimer’s disease

Serum Paraoxonase 2 (PON2) level is a potential biomarker owing to its association with a number of pathophysiological conditions such as atherosclerosis and cardiovascular disease. Since cholinergic deficiency is closely linked with Alzheimer’s disease (AD) progression, acetylcholinesterase inhibitors (AChEIs) are the treatment of choice for patients with AD. However, there is a heterogenous response to these drugs and mostly the subjects do not respond to the treatment. Gene polymorphism, the simultaneous occurrence of two or more discontinuous alleles in a population, could be one of the important factors for this. Hence, we hypothesized that PON2 and its polymorphic forms may be hydrolyzing the AChEIs differently, and thus, different patients respond differently. To investigate this, two AChEIs, donepezil hydrochloride (DHC) and pyridostigmine bromide (PB), were selected. Human PON2 wildtype gene and four mutants, two catalytic sites, and two polymorphic sites were cloned, recombinantly expressed, and purified for in vitro analysis. Enzyme activity and AChE activity were measured to quantitate the amount of DHC and PB hydrolyzed by the wildtype and the mutant proteins. Herein, PON2 esterase activity and AChE inhibitor efficiency were found to be inversely related. A significant difference in enzyme activity of the catalytic site mutants was observed as compared to the wildtype, and subsequent AChE activity showed that esterase activity of PON2 is responsible for the hydrolysis of DHC and PB. Interestingly, PON2 polymorphic site mutants showed increased esterase activity; therefore, this could be the reason for the ineffectiveness of the drugs. Thus, our data suggested that the esterase activity of PON2 was mainly responsible for the hydrolysis of AChEI, DHC, and PB, and that might be responsible for the variation in individual response to AChEI therapy.

Esterase Activity of Serum Albumin Studied by 1H NMR Spectroscopy and Molecular Modelling

Serum albumin possesses esterase and pseudo-esterase activities towards a number of endogenous and exogenous substrates, but the mechanism of interaction of various esters and other compounds with albumin is still unclear. In the present study, proton nuclear magnetic resonance (1H NMR) has been applied to the study of true esterase activity of albumin, using the example of bovine serum albumin (BSA) and p-nitrophenyl acetate (NPA). The site of BSA esterase activity was then determined using molecular modelling methods. According to the data obtained, the accumulation of acetate in the presence of BSA in the reaction mixture is much more intense as compared with the spontaneous hydrolysis of NPA, which indicates true esterase activity of albumin towards NPA. Similar results were obtained for p-nitophenyl propionate (NPP) as substrate. The rate of acetate and propionate release confirms the assumption that there is a site of true esterase activity in the albumin molecule, which is different from the site of the pseudo-esterase activity Sudlow II. The results of molecular modelling of BSA and NPA interaction make it possible to postulate that Sudlow site I is the site of true esterase activity of albumin.

Abstract MP38: Identification Of A Gut Microbe That Attenuates The Blood Pressure Lowering Effect Of ACEi Quinapril

Introduction: Treatment resistant hypertension (rHTN) is present in ~20% of all hypertensive patients. rHTN is critical in African American patients who experience early onset, severe outcomes, and weak responsiveness to angiotensin converting enzyme inhibitor (ACEi). The mechanism for drug resistance is unknown. Gut microbiota harbors biotransformative enzymes such as esterase, which may hydrolyze ACEis, reducing absorption. Our study was to identify microbe responsible for ACEi resistance. Methods: 16-week-old male Spontaneously Hypertensive Rats (SHR) were gavaged with (N=12) or without (N=6) Vancomycin, Meropenem, and Omeprazole (VMO) 50 mg/kg/day for five days to deplete the gut microbiota. A single 8mg/kg dose of quinapril was given to SHR and SHR+VMO before blood pressure (BP) recording via telemetry. Quinapril catabolism was quantified by liquid chromatography-mass spectrometry. Bacterial esterase activity was monitored by hydrolysis of p-nitro-phenylbutyrate. Cecal microbiota was analyzed by 16S rDNA. Fecal microbiota were analyzed by metagenomics in 29 (16 black, 13 white) HTN patients. Results: Quinapril lowered BP more in the SHR+VMO than SHR ( P <0.0001). With a 50% reduction in bacterial 16S copy numbers ( P <0.0001), the SHR+VMO group showed (1) reduced Coprococcus ( P <0.0001); (2) lower esterase activity per gram of cecal microbiota to hydrolyze quinapril ( P =0.0065); (3) a 50% lower reduction in quinapril quantity (nmol) after incubation with 1mg of cecal lysate for 3 hr ( P <0.0001); (4) decreased bacterial genes in KEGG drug metabolism pathway ( P <0.0001). The abundance of Coprococcus positively correlated with genes in drug metabolism ( P <0.0001). Importantly, co-administration of quinapril with C. comes, a species in Coprococcus genus, reduced the BP-lowering effects of quinapril in the SHR ( P <0.0001). Comparison of human microbiota demonstrated a higher abundance of C. comes in the black hypertensives (poor ACEi responder) than the white (ACEi responder) ( P =0.0167). Conclusion: We, for the first time, demonstrate a previously unrecognized role of gut microbes in reducing ACEi effectiveness. This serves a foundation for expanding clinical management of antihypertensive drug resistance via manipulation of gut microbiota.

Sampling efficiency of Candida auris from healthcare surfaces: culture and nonculture detection methods

Sponges and swabs were evaluated for their ability to recover Candida auris dried 1 hour on steel and plastic surfaces. Culture recovery ranged from <0.1% (sponges) to 8.4% (swabs), and cells detected with an esterase activity assay revealed >50% recovery (swabs), indicating that cells may enter a viable but nonculturable state.