Determination of Anti-Pseudomonal Activities of Cocoa (Theobroma cacao) Pod Husk using Time-Kill-Test and Agar-Well Diffusion Techniques

Aim: To determine the antimicrobial effectiveness of cocoa pod husk against P. aeruginosa. Study Design: An experimental research Place and Duration of Study: Department of Medical Microbiology, Olabisi Onabanjo University Teaching Hospital, Sagamu, Ogun State, Nigeria, between June 2015 and Sept. 2016. Materials and Methods: Seventy-seven (77) isolates of P. aeruginosa obtained from three (3) teaching hospitals were involved in this study. Cocoa pod husk was processed into crude extract and its effectiveness against the isolates of P. aeruginosa were examined using agar well diffusion, time-kill test techniques and Anova. Results: The percentage susceptibility of P. aeruginosa to Cocoa pod husk at 500 mg/mL and 250 mg/mL inhibited all the P. aeruginosa but only 14.29% were sensitive at a lower concentration of 31.25 mg/mL. Moreover, the comparison between the broth micro and macro dilution method of determining the MIC of cocoa pod husk against P. aeruginosa highlighted a significant decrease in the mean MIC value of the broth micro dilution method when compared with the broth macro dilution technique (T=13.519, P<0.05). The time kill test emphasized that P. aeruginosa was killed at a lower concentration of 62.5mg/ml at 150mins of introduction in to the Cocoa pod husk suspension. Conclusion: This study revealed that the Cocoa pod husk possesses antibacterial properties. An increase in the concentration of cocoa pod husk increased its antibacterial activity against Pseudomonas aeruginosa. Moreover, the broth micro dilution technique is sensitive for determining the anti-pseudomonal activity.

Development of a Serial Dilution Technique for Obtaining Monoclonal Cell Populations

Single cell-based techniques have drawn the attention of researchers, because they provide invaluable information of various domains ranging from genomics to epigenetics, transcriptomics, and proteomics. Single cell-derived clones provide a reliable and sustainable source of genetic information due to the homogeneity of the cell population. Aiming to obtain single-cell clones, several approaches were engineered, among which, the Limiting dilution approach stands out as a cost-effective and unsophisticated, and easy-to-apply method. Here, we demonstrate how to acquire single cell-derived clones through a simple 1:10 diluting from genetically modified heterogeneous cell populations.

Modelling Broiler Requirements for Lysine and Arginine

Six assays were conducted to investigate male and female broiler responses to standardized ileal digestible (SID) lysine (Lys) and arginine (Arg). Response data were modeled to estimate the efficiency of utilization (k) of both amino acids and adjust factorial models to predict bird intake for SID Lys and SID Arg. In each assay, 1280 Cobb 500® broilers (640 male and 640 female) were randomly assigned to one of sixteen dietary treatments with four replicates of 20 birds. Dietary treatments consisted of crescent levels of SID Lys or SID Arg based on the dilution technique. The values of k determined for each phase (1- to 14-, 15- to 28-, and 29- to 42-d-old) and sex were contrasted using linear regression with groups (sex and phase). The estimated efficiencies were 0.79 for Lys and 0.62 for Arg, which were unaffected by phase or sex. Factorial models based on body weight and weight gain (M1) and on body and feather protein weight and deposition (M2) were applied to estimate the SID Lys and Arg intake for growth. The amino acid intake based on M2 had a lower error of prediction. Broiler chickens require 94.9 and 92.9 mg/d of SID Lys and SID Arg to deposit 1 g of body protein.

Flow rate changes of drippers with dilutions of treated water produced by oil exploration in the Brazilian semiarid region

The liquid residue called “produced water” from the exploitation of oil in the ground and sea is generated in large volumes and has significant polluting potential. In the Brazilian semiarid region, this liquid can be applied to the agricultural lands, if properly treated and applied to the soil by dripping. It is an alternative that can mitigate water scarcity and impacts on the environment. However, the vulnerability of drippers to clogging is a problem and can be mitigated with the dilution technique. The flow rate changes of drippers for the application of dilutions of produced water treated (PW) with underground water (UW) was analyzed. The experiment was conducted in a completely randomized split-split-plot design with three replications. Plots consisted of treatments (D1: 100% of UW, D2: 90% of UW and 10% PW, D3: 80% of UW and 20% of PW, D4: 70% of UW and 30% of PW and D5: 60% of UW and 40% of PW). The split-plots consisted of types of drippers (G1: 1.6 L h-1, G2: - 1.6 L h-1, G3: 1.7 L h-1) and split-split-plots consisted of evaluation times (0, 40, 80, 120 and 160 h). Flow rate (D) and flow rate coefficient of variation (FCV) were taken every 40 hours untill 160 h. The results showed that the G3 emitter was the most resistant to clogging. The dilutions D2 and D3 provided the lowest losses in hydraulic performance in the drip units. The highest rates of clogging occurred in the G2 emitter operating in the D5 dilution

Is the Dilution Technique Underestimating the Picophytoplankton Growth Measurements?

In oceanic communities, picophytoplankton often dominates phytoplankton biomass and productivity. Diel variations in picophytoplankton abundance and growth have been well documented. In the current study, we used flow cytometry to assess the short-term variations (3 h) of the abundance of the most dominant picophytoplankton, Synechococcus spp. and picoeukaryotes, in the coastal regions of northeastern Taiwan. To explore the change in growth and mortality rate in the daytime and over 24 h incubation, we performed a two-point modified dilution experiment for measuring growth, viral lysis, and nanoflagellate grazing rate. In this study, the growth rates of picoeukaryotes were 0.21 and 0.06 h−1, and those of Synechococcus spp. were 0.15 and 0.06 h−1 for daytime and 24 h incubation, respectively, and the values were higher at significant levels in the daytime than those for 24 h incubation. These growth rate values of picoeukaryote and Synechococcus spp. after incubation for 24 h were approximately underestimated at 71% and 55%, respectively. This finding suggests that estimates based on 24 h sampling may not accurately reflect the true growth rate of these populations on ecologically relevant timescales.

Parasitic infection in captive wild mammals and birds in Bangabandhu Sheikh Mujib Safari Park, Cox’s Bazar, Bangladesh

We investigated the infection rate of gastrointestinal (GI) parasite eggs and premature stages from different wild animals and birds in Bangabandhu Sheikh Mujib Safari Park, Dulahazra, Cox’s Bazar. A total of 56 fecal samples were collected from 24 species during July to November 2012 using modified Stoll’s ova dilution technique. Coprology analysis revealed that the overall rate of parasitic infection was 78.6%, of which 51.8% were helminths and 35.7% protozoa. The identified parasites were Paramphistomum spp. (7.1%), Fasciola spp. (5.4%), strongyles (26.8%), Ascaris spp. (3.6%), Strongyloides spp. (7.1%), Dictyocaulus spp. (5.4%), Trichuris spp. (3.6%), Capillaria spp. (5.4%), Heterakis spp. (3.6%), and Balantidium coli (35.7%). Mixed infection (21.4%) was observed in nine animals, including co-infection with Balantidium coli and strongyles in Tiger Panthera tigris, Sambar Deer Rusa unicolor and Pig-tailed Macaque Macaca nemestrina, Strongyloides spp., Trichuris spp. and larvae of Dictyocaulus spp. in Capped Langur Trachypithecus pileatus, Balantidium coli and Capillaria spp. in Clouded Leopard Neofelis nebulosa, Fasciola spp. and Balantidium coli in Spotted Deer Axis axis, Ascaris spp. and strongyles in African Elephant Loxodonta africana, Strongyloides spp. and Heterakis spp. in Peafowl Pavo cristatus and Heterakis spp. and strongyles co-infection in Great Pied Hornbill Buceros bicornis. It is concluded that GI parasites were prevalent in this safari park. Further epidemiological investigation is necessary for controlling parasitic infection.

High susceptibility to zoliflodacin and conserved target (GyrB) for zoliflodacin among 1209 consecutive clinical Neisseria gonorrhoeae isolates from 25 European countries, 2018

Objectives Novel antimicrobials for treatment of gonorrhoea are imperative. The first-in-class spiropyrimidinetrione zoliflodacin is promising and currently in an international Phase 3 randomized controlled clinical trial (RCT) for treatment of uncomplicated gonorrhoea. We evaluated the in vitro activity of and the genetic conservation of the target (GyrB) and other potential zoliflodacin resistance determinants among 1209 consecutive clinical Neisseria gonorrhoeae isolates obtained from 25 EU/European Economic Area (EEA) countries in 2018 and compared the activity of zoliflodacin with that of therapeutic antimicrobials currently used. Methods MICs of zoliflodacin, ceftriaxone, cefixime, azithromycin and ciprofloxacin were determined using an agar dilution technique for zoliflodacin or using MIC gradient strip tests or an agar dilution technique for the other antimicrobials. Genome sequences were available for 96.1% of isolates. Results Zoliflodacin modal MIC, MIC50, MIC90 and MIC range were 0.125, 0.125, 0.125 and ≤0.004–0.5 mg/L, respectively. The resistance was 49.9%, 6.7%, 1.6% and 0.2% to ciprofloxacin, azithromycin, cefixime and ceftriaxone, respectively. Zoliflodacin did not show any cross-resistance to other tested antimicrobials. GyrB was highly conserved and no zoliflodacin gyrB resistance mutations were found. No fluoroquinolone target GyrA or ParC resistance mutations or mutations causing overexpression of the MtrCDE efflux pump substantially affected the MICs of zoliflodacin. Conclusions The in vitro susceptibility to zoliflodacin was high and the zoliflodacin target GyrB was conserved among EU/EEA gonococcal isolates in 2018. This study supports further clinical development of zoliflodacin. However, additional zoliflodacin data regarding particularly the treatment of pharyngeal gonorrhoea, pharmacokinetics/pharmacodynamics and resistance selection, including suppression, would be valuable.

Macrocyclic squaramides as ion pair receptors and fluorescent sensors selective towards sulfates

A library of macrocyclic ion pair receptors was obtained utilizing the high dilution technique. Incorporation of a fluorescent signaling unit in proximity to the amide function gave an optical sensor selective towards sulfates.