Potential degradation of swainsonine by intracellular enzymes of Arthrobacter sp. HW08

Synthesis and characterization of faujasite zeolite membrane for selective enrichment of Arthrobacter sp. in synthetic wastewater

This paper centers on the preparation and characterization of both a clay support and a faujasite zeolite membrane. Additionally, the study explores the development of bacterial media to assess the performance of these prepared membranes. The faujasite zeolite membrane was created using the hydrothermal method, involving the deposition of a faujasite layer to fine-tune the pore sizes of the clay support. The clay supports were crafted from clay which was sieved to particle size Φ ≤ 63 μm, and compacted with 3.0 wt.% activated carbon, then sintered at 1,000 °C. Distilled water fluxes revealed a decrease from 1,500 L m-2 h-1 to a minimum of 412 L m-2 h-1 after 180 min of filtration. Both membranes were characterized by XRF, XRD, FTIR, adsorption-desorption of nitrogen (N2), and SEM-EDS. PCR technique was used for the identification of the isolated Arthrobacter sp., and the retention of the bacteria on the clay support and the faujasite zeolite membrane were found to be 96 and 99%, respectively. The results showed that the faujasite zeolite membrane passed the clay support due to a narrow pore size of the faujasite zeolite membrane of 2.28 nm compared to 3.55 nm for the clay supports.

The Roles of Plant-Growth-Promoting Rhizobacteria (PGPR)-Based Biostimulants for Agricultural Production Systems

The application of biostimulants has been proven to be an advantageous tool and an appropriate form of management towards the effective use of natural resources, food security, and the beneficial effects on plant growth and yield. Plant-growth-promoting rhizobacteria (PGPR) are microbes connected with plant roots that can increase plant growth by different methods such as producing plant hormones and molecules to improve plant growth or providing increased mineral nutrition. They can colonize all ecological niches of roots to all stages of crop development, and they can affect plant growth and development directly by modulating plant hormone levels and enhancing nutrient acquisition such as of potassium, phosphorus, nitrogen, and essential minerals, or indirectly via reducing the inhibitory impacts of different pathogens in the forms of biocontrol parameters. Many plant-associated species such as Pseudomonas, Acinetobacter, Streptomyces, Serratia, Arthrobacter, and Rhodococcus can increase plant growth by improving plant disease resistance, synthesizing growth-stimulating plant hormones, and suppressing pathogenic microorganisms. The application of biostimulants is both an environmentally friendly practice and a promising method that can enhance the sustainability of horticultural and agricultural production systems as well as promote the quantity and quality of foods. They can also reduce the global dependence on hazardous agricultural chemicals. Science Direct, Google Scholar, Springer Link, CAB Direct, Scopus, Springer Link, Taylor and Francis, Web of Science, and Wiley Online Library were checked, and the search was conducted on all manuscript sections in accordance with the terms Acinetobacter, Arthrobacter, Enterobacter, Ochrobactrum, Pseudomonas, Rhodococcus, Serratia, Streptomyces, Biostimulants, Plant growth promoting rhizobactera, and Stenotrophomonas. The aim of this manuscript is to survey the effects of plant-growth-promoting rhizobacteria by presenting case studies and successful paradigms in various agricultural and horticultural crops.

Swainsonine Induces Liver Inflammation in Mice via Disturbance of Gut Microbiota and Bile Acid Metabolism

Swainsonine induced liver inflammation in livestock; however, the underlying mechanisms, especially the role of bile acids (BAs), in the pathogenesis remained elusive. Here, our results showed that swainsonine induced hepatic inflammation via changing BA metabolism and gut microbiota in mice. Swainsonine significantly upregulated the levels of deoxycholic acid (DCA) and taurine-β-muricholic acid (T-β-MCA) in the serum and liver of mice due to the markedly increased genus Clostridium and the decreased genus Lactobacillus in the gut. As antagonists of the farnesoid X receptor (FXR), elevated DCA and T-β-MCA inhibited hepatic Fxr gene expression and thus suppressed FXR-SHP signaling and activated hepatic Cyp7a1 gene expression, which induced a significant upregulation of the total BA level in serum, contributing to liver inflammation. These findings offer new insights into the underlying mechanisms in which swainsonine induced liver inflammation in mice via the gut-liver axis and suggest that gut microbiota and its metabolite BAs may be underlying triggering factors.

Maternal exposure to swainsonine impaired the early postnatal development of mouse dentate gyrus of offspring

Neurogenesis in the dentate gyrus (DG) plays a key role in the normal of structure and function of the hippocampus-learning and memory. After eating the locoweeds, animals develop a chronic neurological disease called "locoism". Swainsonine (SW) is the main toxin in locoweeds. Studies have shown that SW induces neuronal apoptosis in vitro and impairs learning and memory in adult mouse. The present study explored effects of SW exposure to dams on the postnatal neurogenesis of DG of offspring. Pregnant ICR mice were orally gavaged with SW at a dose of 0, 5.6 or 8.4 mg/kg/day from gestation day 10 to postnatal day (PND) 21, respectively. We found that SW impaired the proliferation capacity of neural progenitor cells in the DG so that the number of newborn cells was reduced at PND 8. Using the postnatal in vivo electroporation, we showed that the dendritic branching and total length of granule cells were significantly decreased due to SW exposure. In addition, on PND 21, the density of NeuN-positive and Reelin-positive interneurons increased in the hilus, implying the disorder of neuronal migration. These results suggest that maternal exposure to SW, the neurogenesis of DG on offspring was disrupted, finally leading to the functional disorder of DG.

Degradation of Swainsonine by the NADP-Dependent Alcohol Dehydrogenase A1R6C3 in Arthrobacter sp. HW08

Swainsonine is an indolizidine alkaloid that has been found in locoweeds and some fungi. Our previous study demonstrated that Arthrobacter sp. HW08 or its crude enzyme extract could degrade swainsonie efficiently. However, the mechanism of swainsonine degradation in bacteria remains unclear. In this study, we used label-free quantitative proteomics method based on liquid chromatography-electrospray ionization-tandem mass spectrometry to dissect the mechanism of swainsonine biodegradation by Arthrobacter sp. HW08. The results showed that 129 differentially expressed proteins were relevant to swainsonine degradation. These differentially expressed proteins were mostly related to the biological process of metabolism and the molecular function of catalytic activity. Among the 129 differentially expressed proteins, putative sugar phosphate isomerase/epimerase A1R5X7, Acetyl-CoA acetyltransferase A0JZ95, and nicotinamide adenine dinucleotide phosphate (NADP)-dependent alcohol dehydrogenase A1R6C3 were found to contribute to the swainsonine degradation. Notably, NADP-dependent alcohol dehyrodgenase A1R6C3 appeared to play a major role in degrading swainsonine, but not as much as Arthrobacter sp. HW08 did. Collectively, our findings here provide insights to understand the mechanism of swainsonine degradation in bacteria.

Simple Indolizidine and Quinolizidine Alkaloids

This review of simple indolizidine and quinolizidine alkaloids (i.e., those in which the parent bicyclic systems are in general not embedded in polycyclic arrays) is an update of the previous coverage in Volume 55 of this series (2001). The present survey covers the literature from mid-1999 to the end of 2013; and in addition to aspects of the isolation, characterization, and biological activity of the alkaloids, much emphasis is placed on their total synthesis. A brief introduction to the topic is followed by an overview of relevant alkaloids from fungal and microbial sources, among them slaframine, cyclizidine, Steptomyces metabolites, and the pantocins. The important iminosugar alkaloids lentiginosine, steviamine, swainsonine, castanospermine, and related hydroxyindolizidines are dealt with in the subsequent section. The fourth and fifth sections cover metabolites from terrestrial plants. Pertinent plant alkaloids bearing alkyl, functionalized alkyl or alkenyl substituents include dendroprimine, anibamine, simple alkaloids belonging to the genera Prosopis, Elaeocarpus, Lycopodium, and Poranthera, and bicyclic alkaloids of the lupin family. Plant alkaloids bearing aryl or heteroaryl substituents include ipalbidine and analogs, secophenanthroindolizidine and secophenanthroquinolizidine alkaloids (among them septicine, julandine, and analogs), ficuseptine, lasubines, and other simple quinolizidines of the Lythraceae, the simple furyl-substituted Nuphar alkaloids, and a mixed quinolizidine-quinazoline alkaloid. The penultimate section of the review deals with the sizable group of simple indolizidine and quinolizidine alkaloids isolated from, or detected in, ants, mites, and terrestrial amphibians, and includes an overview of the "dietary hypothesis" for the origin of the amphibian metabolites. The final section surveys relevant alkaloids from marine sources, and includes clathryimines and analogs, stellettamides, the clavepictines and pictamine, and bis(quinolizidine) alkaloids.