Morphological, anatomical and antibacterial characteristics of Persicaria maculosa Gray plants growing in Lang Sen Wetland Reserve, Long An province, Vietnam

This study aimed to understand the adaptation characteristics of species Persicaria maculosa to living conditions and to add data on them as folk medicinal plants of Vietnam. Research methods included analysis of external morphological characteristics and microscopic structure of stems, leaves and roots. The antibacterial activities of ethanol plant extracts on four bacterial strains were also conducted through agar well diffusion method. The results showed that the plants had formed morphological and anatomical features to adapt to waterlogging and shade conditions. The leaf extracts from the concentrations of 600 to 1,000 mg/L had bacteriostatic activities against all four experimental strains with the bacterial inhibition zones from 2.39 to 10.91 mm, in which inhibition of Bacillus cereus was the best.

Unknown Extracellular and Bioactive Metabolites of the Genus Alexandrium: A Review of Overlooked Toxins

Various species of Alexandrium can produce a number of bioactive compounds, e.g., paralytic shellfish toxins (PSTs), spirolides, gymnodimines, goniodomins, and also uncharacterised bioactive extracellular compounds (BECs). The latter metabolites are released into the environment and affect a large range of organisms (from protists to fishes and mammalian cell lines). These compounds mediate allelochemical interactions, have anti-grazing and anti-parasitic activities, and have a potentially strong structuring role for the dynamic of Alexandrium blooms. In many studies evaluating the effects of Alexandrium on marine organisms, only the classical toxins were reported and the involvement of BECs was not considered. A lack of information on the presence/absence of BECs in experimental strains is likely the cause of contrasting results in the literature that render impossible a distinction between PSTs and BECs effects. We review the knowledge on Alexandrium BEC, (i.e., producing species, target cells, physiological effects, detection methods and molecular candidates). Overall, we highlight the need to identify the nature of Alexandrium BECs and urge further research on the chemical interactions according to their ecological importance in the planktonic chemical warfare and due to their potential collateral damage to a wide range of organisms.

Biochemical compositions, antioxidant activity, and in vitro antibacterial activity of extract from wild bitter melon (Momordica charantia var. abbreviata Ser.)

Wild bitter melon (Momordica charantia var. abbreviata Ser.) is a type of vine that grows wildly in the mountains and plains in Vietnam. The main use parts of the tree are fruit, stem, and leaf that can be eaten as vegetables. This study aims to (1) identify several bioactive chemical compounds in the stems and leaves of bitter melon trees in the forests in the district of Mang Yang, Gia Lai province; (2) evaluate the nutrient composition, antioxidant activity, and antimicrobial ability of fresh juice and extract with ethanol 70°. The results indicated that fresh juice and ethanol 70° extract currently inhibited the growth of experimental strains of microorganisms, in which ethanol 70o extract gives the highest antimicrobial effect. The qualitative results determined that the chemical components of wide bitter melon consist of flavonoids, saponins, tannins, free reducing sugar, organic acids, starch, and fatty acids as the basis for the standardization of exploitation of medicinal resources this material.

Alpha amylase activity and its relation with the falling number in experimental strains of triticale and tricepiro with potential use in the production of bioetanol

En el presente trabajo se determinó la actividad de alfa amilasas y el Falling Number (FN) en harinas de diez líneas experimentales de tritíceas cultivadas en el Campo Experimental de la Facultad de Agronomía, Universidad Nacional de La Pampa, Argentina. Se realizó la conversión de FN al Número de Licuefacción (LN) para obtener la linealidad de la relación con las alfas amilasas. Se evaluó el grado de asociación de la actividad de las enzimas alfa amilasas con los valores de FN y LN. Se encontró variabilidad genética en la actividad amilásica entre las líneas estudiadas. Algunos genotipos presentaron alta actividad de las enzimas alfa amilasas haciéndolos atractivos para su utilización en la producción de bioetanol. Se obtuvo una correlación de Pearson altamente significativa (p<0,001) de 0,92 entre FN y la actividad de alfa amilasas para el año 2014 y de 0,71 para el año 2015. La alta correlación encontrada entre los valores de FN, LN y la actividad de alfa amilasas, indica que esta técnica podría utilizarse en reemplazo del FN en aquellas situaciones en que no se disponga del equipo.

Synergistic activity of colistin combined with PFK-158 against colistin-resistant and colistin-susceptible Gram-negative bacteria

Background: The emergence of colistin resistance among Gram-negative bacteria poses a serious public health threat and warrants immediate action. Therefore, it is necessary to enhance the antibacterial activity of colistin through the combination with other drugs. In this study, we demonstrate the synergistic activity of colistin combined with PFK-158 against colistin-susceptible but more importantly against colistin-resistant Gram-negative bacteria, including non-fermenting bacteria (P. aeruginosa, A. baumannii) and Enterobacteriaceae (E. coli and K. pneumoniae).Methods: 18 colistin-resistant and 12 colistin-susceptible Gram-negative bacteria were collected as the experimental strains, and the minimum inhibitory concentrations (MICs) of colistin and PFK-158 against all strains were determined by the broth microdilution method. The MICs of routine antimicrobial agents including aztreonam (ATM), ceftazidime (CAZ), cefepime (FEP), imipenem (IMP), ciprofloxacin (CIP), levofloxacin (LVX), gentamicin (GEN), tobramycin (TOB) for all 30 experimental strains were determined by bioMerieux VITEK-2 (BioMérieux, Marcy-l’Étoile, France). The synergistic activity of colistin combined with PFK-158 in vitro was assessed using the checkerboard assay and the time-kill assays.Results: The results of the checkerboard assay showed that when colistin was used in combination with PFK-158, synergistic activity was observed against the 18 colistin-resistant and the 8 colistin-susceptible Gram-negative bacteria, and the remaining 4 colistin-susceptible strains showed additive activity. No irrelevant activity and antagonistic activity was observed for all strains. The results of the time-killing assays presented that the killing activity against the colistin-resistant Gram-negative bacterium were evident for the combination of colistin and PFK-158, compared with the groups adding colistin or PFK-158 alone. Conclusions: In conclusion, our results strongly exhibited that the combination of colistin and PFK-158 displayed the significant synergistic activity against all tested colistin-resistant and most colistin-susceptible Gram-negative strains. PFK-158 was found to potentiate the antibacterial activity of colistin against a wide panel of colistin-resistant and colistin-susceptible Gram-negative strains no matter what species (including non-fermenting bacteria and Enterobacteriaceae). It may be a potential new choice for the treatment of infections caused by the clinical Gram-negative strains.

The Application of Digital Volume Correlation (DVC) to Evaluate Strain Predictions Generated by Finite Element Models of the Osteoarthritic Humeral Head

Continuum-level finite element models (FEMs) of the humerus offer the ability to evaluate joint replacement designs preclinically; however, experimental validation of these models is critical to ensure accuracy. The objective of the current study was to quantify experimental full-field strain magnitudes within osteoarthritic (OA) humeral heads by combining mechanical loading with volumetric microCT imaging and digital volume correlation (DVC). The experimental data was used to evaluate the accuracy of corresponding FEMs. Six OA humeral head osteotomies were harvested from patients being treated with total shoulder arthroplasty and mechanical testing was performed within a microCT scanner. MicroCT images (33.5 µm isotropic voxels) were obtained in a pre- and post-loaded state and BoneDVC was used to quantify full-field experimental strains (≈ 1 mm nodal spacing, accuracy = 351 µstrain, precision = 518 µstrain). Continuum-level FEMs with two types of boundary conditions (BCs) were simulated: DVC-driven and force-driven. Accuracy of the FEMs was found to be sensitive to the BC simulated with better agreement found with the use of DVC-driven BCs (slope = 0.83, r2 = 0.80) compared to force-driven BCs (slope = 0.22, r2 = 0.12). This study quantified mechanical strain distributions within OA trabecular bone and demonstrated the importance of BCs to ensure the accuracy of predictions generated by corresponding FEMs.

An Experimental Strain-Based Study on the Working State of Husk Mortar Wallboards with Openings

Rice husks as common agricultural remnants with low density and good thermal conductivity properties have been used in infill walls in the northern area of China. Accordingly, many tests and numerical simulations were conducted to address a difficult issue, the inaccurate estimation on the lateral load-bearing capacity of different types of husk mortar energy-saving (HMES) wallboards. The difficulty has not been overcome so far, implying that the novel methods are anticipated to achieve the accurate estimation. This paper tests the full-scale HMES wallboards with different openings and obtains the strains at the points distributed on the wallboard sides. The experimental strains are modeled as the approximate strain energy values to produce the characteristic parameter of the HMES wallboard’s stressing state. Furthermore, the inherent working state characteristic points of HMES wallboards are revealed from the evolution of the characteristic parameter called as the normalized approximate strain energy sum, leading to the redefinition of the failure loads for the HMES wallboards. Finally, it investigates the stressing state mode evolution of the HMES wallboard around the failure loads. The achieved results provide the reference to the accurate estimation of the bearing capacity of the HMES wallboards.

Modification of Fecal Bacteria Counts and Blood Immune Cells in the Offspring of BALB/c and C57BL/6 Mice Obtained through Interstrain Mouse Embryo Transfer

The reproducibility of results obtained with rodent models depends on the genetic purity of the strain and the stability of the environment. However, another potential factor is changes in the gut microbiota due to the transmission of mother’s bacteria during embryo transfer. In this study, we demonstrate the transmission of the microbiota and immune cell blood phenotype to the offspring of 2 strains, C57BL/6JNskrc and BALB/cJNskrc, from surrogate dams of different genotypes. Interstrain embryo transfer resulted in a change in the number of Enterococcus spp. organisms, as shown by quantitative PCR analysis. The number of blood leukocytes was also affected, as estimated by flow cytometry. The number of blood leukocytes, including B cells and helper T cells, and the number of Enterococcus spp. organisms in male C57BL/6JNskrc offspring bornto BALB/cJNskrc surrogate dams became similar to those of male BALB/cJNskrc mice born to BALB/cJNskrc dams. Likewise, the same parameters of male BALB/cJNskrc mice born to C57BL/6JNskrc dams became similar to those of male C57BL/6JNskrc offspring. Researchers should be aware of the possible transmission of the dam’s microbiota and immune cell phenotypes to the experimental strains when planning embryo transfer experiments, because these factors could affect the experimental outcomes or the reproducibility of experimental results.