Photocatalytic dye degradation and photoexcited anti-microbial activities of green zinc oxide nanoparticles synthesized via Sargassum muticum extracts

Drug-resistant superbugs (DRS) were isolated from hospital sewage waste and confirmed by a 16S rDNA molecular technique as B. filamentosus, B. flexus, P. stutzeri, and A. baumannii.

Resistance and Resilience of Soil Nitrogen Cycling to Drought and Heat Stress in Rehabilitated Urban Soils

In the context of climate change and biodiversity loss, rehabilitation of degraded urban soils is a means of limiting artificialization of terrestrial ecosystems and preventing further degradation of soils. Ecological rehabilitation approaches are available to reinitiate soil functions and enhance plant development. However, little is known about the long-term stability of rehabilitated soils in terms of soil functions when further natural or anthropogenic perturbations occur. Based on rehabilitated urban soils, the present study sought to evaluate the resistance and resilience of soil functions linked to carbon cycling and phosphate dynamics in addition to nitrogen cycling and related microbial communities after a heat and drought stress. A laboratory experiment was conducted in microcosms under controlled temperature conditions, with four contrasted soils collected from a rehabilitated urban brownfield; an initial, non-rehabilitated soil (IS), a technosol with a high organic matter level (HO), and two technosols with less organic matter (LO1 and LO2), together with their respective controls (no stress). Changes in potential denitrification (PDR), nitrification (PNR) rates, and their interactive relationships with soil microbial activities and soil physicochemical properties were determined following a combined heat (40°C) and drought stress period of 21 days. Measurements were carried out immediately after the stress (resistance), and then also 5, 30, and 92 days after soil rewetting at 60% water holding capacity (resilience). Microbial activities involved in soil functions such as carbon cycling and phosphate dynamics proved to be of low resistance in all soils except for IS; however, they were resilient and recovered rapidly after rewetting. On the other hand, the microbial activities and gene abundances that were measured in relation to nitrogen cycling processes showed that for denitrification, activities were more rapidly resilient than gene abundances whereas for nitrification the activities and gene abundances were resilient in the same way. Results suggest that, unless the soils contain high amounts of organic matter, microbial communities in imported soils can be more vulnerable to environmental pressures such as drought and heat than communities already present. This should be considered when rehabilitating degraded soils.

Intestinal Transgene Delivery with Native E. coli Chassis Allows Persistent Physiological Changes

Live bacterial therapeutics (LBT) could reverse disease by engrafting in the gut and providing persistent beneficial functions in the host. However, attempts to functionally manipulate the gut microbiome of conventionally-raised (CR) hosts have been unsuccessful, because engineered microbial organisms (i.e., chassis) cannot colonize the hostile luminal environment. In this proof-of-concept study, we use native bacteria as chassis for transgene delivery to impact CR host physiology. Native Escherichia coli isolated from stool cultures of CR mice were modified to express functional bacterial (bile salt hydrolase) and eukaryotic (Interleukin-10) genes. Reintroduction of these strains induces perpetual engraftment in the intestine. In addition, engineered native E. coli can induce functional changes that affect host physiology and reverse pathology in CR hosts months after administration. Thus, using native bacteria as chassis to knock-in specific functions allows mechanistic studies of specific microbial activities in the microbiome of CR hosts, and enables LBT with curative intent.

The Antidiabetic and Anti-microbial Activity Analyses in The Extract of Methanol, Ethyl Acetate, and Hexane from Flesh of Matoa (Pometia pinnata J. R. Forst. & G. Forst)

The current research was designed to examine the antidiabetic and anti-microbial activities in the extracts of methanol, ethyl acetate and hexane from Flesh of Matoa (Pometia pinnata J. R. Forst. & G. Forst) to find out the best solvent to produce antidiabetic and anti-microbial active compounds. In the phytochemical screening, hexane extracted alkaloids and terpenoids, while ethyl acetate extracted saponin and methanol extracted tannin, phenol and terpenoids. In the antidiabetic activity by a-glucosidase inhibition methods, ethyl acetate showed the highest percentage of inhibition and the smallest value of IC50, followed by hexane and methanol compared to the Quercetin as the control group. The maximum percentage inhibition was 36.74 ± 0.07 for 100 µg/mL of concentration. The minimum value of IC50 was observed at 159.74 ± 0.65 µg/ml compared to the control group 6.04 ± 0.14 µg/ml. The smaller the IC50 value, the stronger the antidiabetic activity. Anti-microbial inhibition activities assessed using anti-microbial diffusion test method. The hexane and ethyl acetate extracts provide an inhibition of fungi and bacteria compared to Ketoconazole and Amoxicillin as the standard. The maximum fungi inhibition zone was observed at 4 mm for A. flavus and 9 mm for A. niger by Hexane extracts compared to the standard 14 and 24 mm. The maximum bacteria inhibition zone was observed at 7 mm for B. cereus by both of hexane and ethyl acetate extracts compared to the standard 5 mm. Compared to the anti-microbe inhibitory power categories, hexane and ethyl acetate was on the range of weak and moderate. The methanol extract could not inhibit all types of microbe. This study concluded that various extract of flesh of Matoa showed antidiabetic and anti-microbial activities at different value with varying potencies. The ethyl acetate extract was found to be more potent among all, followed by hexane and methanol. HIGHLIGHTS Phytochemical screening of Flesh of Matoa (Pometia pinnata R. Forst. & G. Forst) produced alkaloids, terpenoids, saponin, tannin, phenol and terpenoids In the antidiabetic activity by a-glucosidase inhibition methods, ethyl acetate showed the highest percentage of inhibition and the smallest value of IC50, followed by hexane and methanol The hexane and ethyl acetate extracts provide an inhibition of fungi and bacteria compared to Ketoconazole and Amoxicillin as the standard GRAPHICAL ABSTRACT