A strain of Bacillus licheniformis T5 was isolated from soil contaminated with crude oil due to its efficient degradation of polycyclic aromatic hydrocarbons (PAHs). When subjected to stress metabolism using phenanthrene as a carbon source, significant changes were observed in T5 cells. Infrared spectrum analysis revealed the presence of -C=C- and Ph-O-C (aromatic) groups on the bacterial surface, facilitating the adsorption of PAHs on the phospholipid layer and causing damage to the cell membrane. Scanning electron microscope (SEM) analysis showed the changes of cell morphology, including a large number of folds on the lower surface and the folding of cell membrane. Transmission electron microscope (TEM) observation showed that non-stressed bacteria with adequate nutritional conditions accumulated more lipids. However, the stress group contained more protein. It was found that stress metabolism led to the increase of protein content in T5 cells by 16.4% and the activity of oxidoreductase more than doubled. These physiological and biochemical changes enhance the ability of stressed bacteria to degrade PAHs efficiently, thereby reducing the degradation cycle. The findings offer valuable insights for the remediation of PAHs pollution.

To delve into the growth and physiological adaptations exhibited by the economically vital black wolfberry (Lycium ruthenicum) upon inoculation with arbuscular mycorrhizal fungi (AMF) under varying levels of saline-alkaline stress A series of pot experiments were conducted in a gradient saline-alkaline environment (0, 200, 400 mM NaCl: NaHCO3 = 1:1). One-year-old cuttings of black wolfberry, inoculated with two AMF species-Funneliformis mosseae (Fm) and Rhizophagus intraradices (Ri)-served as the experimental material, enabling a comprehensive analysis of seedling biomass, chlorophyll content, antioxidant enzyme activities, and other crucial physiological parameters. This study demonstrated that both Fm and Ri could form a symbiotic relationship with the root of Lycium ruthenicum. Notably, Fm inoculation significantly bolstered the growth of the underground parts, while exhibiting a remarkable capacity to scavenge reactive oxygen species (ROS), thereby effectively mitigating membrane oxidative damage induced by stress. Additionally, Fm promoted the accumulation of abscisic acid (ABA) in both leaves and roots, facilitating the exclusion of excess sodium ions from cells. Ri Inoculation primarily contributed to an enhancement in the chlorophyll b (Chlb) content, vital for sustaining photosynthesis processes. Furthermore, Ri's ability to enhance phosphorus (P) absorption under stressful conditions ensured a steady influx of essential nutrients. These findings point to different strategies employed for Fm and Ri inoculation. To holistically assess the saline-alkaline tolerance of each treatment group, a membership function analysis was employed, ultimately ranking the salt tolerance as Fm > Ri > non-mycorrhizal (NM) control. This finding holds paramount importance for the screening of highly resilient Lycium ruthenicum strains and offers invaluable theoretical underpinnings and technical guidance for the remediation of saline-alkaline soils, fostering sustainable agricultural practices in challenging environments.

Background Seed aging, a natural and inevitable process occurring during storage. Oats, an annual herb belonging to the Gramineae family and pooideae. In addition to being a healthy food, oats serve as ecological pastures, combating soil salinization and desertification. They also play a role in promoting grassland agriculture and supplementing winter livestock feed. However, the high lipid and fat derivatives contents of oat seeds make them susceptible to deterioration, as fat derivatives are prone to rancidity, affecting oat seed production, storage, development, and germplasm resource utilization. Comparative studies on the effects of aging on physiology and cytological structure in covered and naked oat seeds are limited. Thus, our study aimed to determine the mechanism underlying seed deterioration in artificially aged 'LongYan No. 3' (A. sativa) and 'BaiYan No. 2' (A. nuda) seeds, providing a basis for the physiological evaluation of oat seed aging and serving as a reference for scientifically safe storage and efficient utilization of oats. Results In both oat varieties, superoxide dismutase and catalase activities in seeds showed increasing and decreasing trends, respectively. Variance analysis revealed significant differences and interaction in all measured indicators of oat seeds between the two varieties at different aging times. 'LongYan No. 3' seeds, aged for 24-96 h, exhibited a germination rate of < 30%, Conductivity, malondialdehyde, soluble sugar, and soluble protein levels increased more significantly than the 'BaiYan No. 2'. With prolonged aging leading to cell membrane degradation, reactive oxygen species accumulation, disrupted antioxidant enzyme system, evident embryo cell swelling, and disordered cell arrangement, blocking the nutrient supply route. Simultaneously, severely concentrated chromatin in the nucleus, damaged mitochondrial structure, and impaired energy metabolism were noted, resulting in the loss of 'LongYan No. 3' seed vitality and value. Conversely, 'BaiYan No. 2' seeds showed a germination rate of 73.33% after 96 h of aging, consistently higher antioxidant enzyme activity during aging, normal embryonic cell shape, and existence of the endoplasmic reticulum. Conclusions ROS accumulation and antioxidant enzyme system damage in aged oat seeds, nuclear chromatin condensation, mitochondrial structure damage, nucleic acid metabolism and respiration weakened, oat seed vigor decreased. 'LongYan No. 3' seeds were more severely damaged under artificial aging than 'BaiYan No. 2' seeds, highlighting their heightened susceptibility to aging effects.

Pigments are an essential part of everyday life on Earth with rapidly growing industrial and biomedical applications. Synthetic pigments account for a major portion of these pigments that in turn have deleterious effects on public health and environment. Such drawbacks of synthetic pigments have shifted the trend to use natural pigments that are considered as the best alternative to synthetic pigments due to their significant properties. Natural pigments from microorganisms are of great interest due to their broader applications in the pharmaceutical, food, and textile industry with increasing demand among the consumers opting for natural pigments. To fulfill the market demand of natural pigments new sources should be explored. Cold-adapted bacteria and fungi in the cryosphere produce a variety of pigments as a protective strategy against ecological stresses such as low temperature, oxidative stresses, and ultraviolet radiation making them a potential source for natural pigment production. This review highlights the protective strategies and pigment production by cold-adapted bacteria and fungi, their industrial and biomedical applications, condition optimization for maximum pigment extraction as well as the challenges facing in the exploitation of cryospheric microorganisms for pigment extraction that hopefully will provide valuable information, direction, and progress in forthcoming studies.

The genus Arthrobacter is a source of many natural products that are critical in the development of new medicines. Here, we isolated a novel carotenoid from Arthrobacter sp. QL17 and characterized its properties. The carotenoid was extracted with methanol, and purified by column chromatography and semi-preparative HPLC. Based on micrOTOF-Q and NMR analyses, the pigment was chemically characterized as 2,2 '-((((1E,3E,5E,7E,9E,11E,13E,15E,17E,19E)-3,7,14,18-tetramethylicosa-1,3,5,7,9,11,13,15,17,19-decaene-1,20-diyl)bis(2,2,4-trimethylcyclohex-3-ene-3,1-diyl)) bis(ethan-2-yl-1-ylidene))bi(propane-1,3-diol), and named arthroxanthin. The biological activities of arthroxanthin were evaluated with DPPH, ABTS and MTT assays. Arthroxanthin exhibited excellent radical scavenging properties, as shown for 2, 20-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-n-(3,2-ethyl-benzothiazole-6-sulfonic acid) ammonium salt (ABTS), respectively, with IC50s of 69.8 and 21.5 mu g/mL. It also showed moderate anticancer activities against HepG2, Hela, MDAB-231, SW480, and MKN-45 with IC50 values of 107.6, 150.4, 143.4, 195.9, and 145.5 mu g/mL, respectively. Therefore, arthroxanthin derived from Arthrobacter sp. QL17 may be a potent antioxidant and anticancer agent for food and pharmaceutical use.