The LysR-type transcriptional regulator CysB controls the repression of hslJ transcription in Escherichia coli

The LysR-type transcriptional regulator (LTTR) CysB is a transcription factor in Escherichia coli cells, where as a homotetramer it binds the target promoter regions and activates the genes involved in sulphur utilization and sulphonate-sulphur metabolism, while negatively autoregulating its own transcription. The hslJ gene was found to be negatively regulated by CysB and directly correlated with novobiocin resistance of the bacterium. cysB mutants showed upregulation of the hslJ:: lacZ gene fusion and exhibited increased novobiocin resistance. In this study the hslJ transcription start point and the corresponding putative sigma(70) promoter were determined. The hslJ promoter region was defined by employing different hslJ-lacZ operon fusions, and transcription of the hslJ gene was shown to be subject to both repression imposed by the CysB regulator and direct or indirect autogenous negative control. These two regulations compete to some extent but they are not mutually exclusive. CysB acts as a direct repressor of hslJ transcription and binds the hslJ promoter region that carries the putative CysB repressor site. This CysB binding, apparently responsible for repression, is enhanced in the presence of the ligand N-acetylserine (NAS), hitherto considered to be a positive cofactor in CysB-mediated gene regulations. Interallelic complementation of characterized CysB mutants I33N and S277Ter partially restored the repression of hslJ transcription and the consequent novobiocin sensitivity, but did not complement the cysteine auxotrophy

Identification of the CysB-regulated gene, hslJ, related to the Escherichia coli novobiocin resistance phenotype

The cysB gene product is a LysR-type regulatory protein required for expression of the cys regulon. cysB mutants of Escherichia coli and Salmonella, along with being auxotrophs for the cysteine, exhibit increased resistance to the antibiotics novobiocin (Nov) and mecillinam. In this work, by using lambdaplacMu9 insertions creating random lacZ fusions, we identify a gene, hslJ, whose expression appeared to be increased in cysB mutants and needed for Nov resistance. Measurements of the hslJ::IacZ gene fusion expression demonstrated that the hslJ gene is negatively regulated by CysB. In addition we observe the negative autogenous control of HslJ. When the control imposed by CysB is lifted in the cysB mutant, the elevation of Nov resistance can be achieved only in the presence of wild-type hslJ allele. A double cysB hslJ mutant restores the sensitivity to Nov. Overexpression of the wild-type HslJ protein either in a cysB(+) or a cys(B-) background increases the level of Nov resistance indicating that hslJ product is indeed involved in accomplishing this phenotype. The hslJ::OmegaKan allele encodes the C-terminaly truncated mutant protein HslJ Q121Ter which is not functional in achieving the Nov resistance but when overexpressed induces the psp operon. Finally, we found that inactivation of hslJ does not affect the increased resistance to mecillinam in cysB mutants

Understanding How Microplastics Affect Marine Biota on the Cellular Level Is Important for Assessing Ecosystem Function: A Review

Plastic has become indispensable for human life. When plastic debris is discarded into waterways, these items can interact with organisms. Of particular concern are microscopic plastic particles (microplastics) which are subject to ingestion by several taxa. This review summarizes the results of cutting-edge research about the interactions between a range of aquatic species and microplastics, including effects on biota physiology and secondary ingestion. Uptake pathways via digestive or ventilatory systems are discussed, including (1) the physical penetration of microplastic particles into cellular structures, (2) leaching of chemical additives or adsorbed persistent organic pollutants (POPs), and (3) consequences of bacterial or viral microbiota contamination associated with microplastic ingestion. Following uptake, a number of individual-level effects have been observed, including reduction of feeding activities, reduced growth and reproduction through cellular modifications, and oxidative stress. Microplastic-associated effects on marine biota have become increasingly investigated with growing concerns regarding human health through trophic transfer. We argue that research on the cellular interactions with microplastics provide an understanding of their impact to the organisms’ fitness and, therefore, its ability to sustain their functional role in the ecosystem. The review summarizes information from 236 scientific publications. Of those, only 4.6% extrapolate their research of microplastic intake on individual species to the impact on ecosystem functioning. We emphasize the need for risk evaluation from organismal effects to an ecosystem level to effectively evaluate the effect of microplastic pollution on marine environments. Further studies are encouraged to investigate sublethal effects in the context of environmentally relevant microplastic pollution conditions

Ultramafic vegetation and soils in the circumboreal region of the Northern Hemisphere

The paper summarizes literature on climate, soil chemistry, vegetation and metal accumulation by plants found on ultramafic substrata in the circumboreal zone (sensu Takhtajan, Floristic regions of the world, 1986) of the Northern Hemisphere. We present a list of 50 endemic species and 18 ecotypes obligate to ultramafic soils from the circumboreal region of Holarctic, as well as 30 and 2 species of Ni and Zn hyperaccumulators, respectively. The number of both endemics and hyperaccumulators are markedly lower compared to that of the Mediterranean and tropical regions. The diversity of plant communities on ultramafics soils of the circumboral region is also described. The underlying causes for the differences of ultramafic flora between arctic, cold, cool temperate and Mediterranean and tropical regions are also discussed. © 2018, The Ecological Society of Japan

Influence of hyper‐harmonized fullerene water complex on collagen quality and skin function

Background Fullerene water complex establishes the optimal order and function of biomolecules in natural, biophysical way by transducing the signal through water hydrogen bonds to biomolecules. Objectives This paper considers the effects of the patented hyper-harmonized-hydroxylated fullerene water complex (3HFWC) on biophysical properties of the skin collagen molecules. Method Optomagnetic imaging spectroscopy (OMIS) has been used for the analysis of the biophysical skin properties (diamagnetic/paramagnetic) after applying three groups of different cosmetic products. Tested cosmetic products were prepared by replacing the active ingredients with 3HFWC or with water in four commercial products. The original commercial creams and their vehiculums with water added served as control groups. Data were statistically analyzed using paired t test in R software. Results t Test gave statistically significant results for all of the products with 3HFWC, while within the control group, only body lotion and hand cream did show statistically significant results (P lt 0.05). Significant improvements in abundance and quality of collagen in the dermis were achieved with body lotion with 3HFWC (p(+)/p(-)ranged from 0.82 to 0.97). While body lotion vehiculum made collagen-water interaction more stable (p(+)/p(-)ranged from 0.3 to 0.55), hand cream with 3HFWC made it more dynamic (p(+)/p(-)ranged from 0.63 to 0.49). Body lotion vehiculum improved the compactness of the dermis (p(+)/p(-)ranged from 0.2 to 1.03), as well as commercial hand cream (p(+)/p(-) ranged from 0.28 to 0.85). Conclusion Compared to the control groups, cosmetic products with 3HFWC demonstrated positive effects on the biophysical properties of the skin. Increased paramagnetic properties are linked to more unpaired electrons, their faster movement, and, finally, better signal transduction. Thus, products with 3HFWC could enable faster regeneration of collagen and prompt skin reaction to the negative environmental influences

The role and immunophenotypic characteristics of myofibroblasts in liver of sheep naturally infected with the lancet liver fluke (Dicrocoelium dendriticum)

The main objective of our research was to examine the role and immunophenotypic characteristics of myofibroblasts in sheep liver naturally infected by the lancet liver fluke (Dicrocoelium dendriticum). In the reported study we analyzed liver samples from 20 adult sheep, 14 infected animals and 6 controls. The liver samples were fixed in 10% buffered formalin, and routinely processed and stained using hematoxylin eosin, the periodic acid-Schiff and Masson-Goldner trichrome methods. The immunohistochemical examination was carried out by the streptavidin biotin (LSAB2) method, using antibodies for alpha-smooth muscle actin (alpha-SMA), desmin and vimentin. The histopathological examination revealed liver fibrosis in 6 out of 14 (42.9%) analyzed samples, while different forms of cholangitis were observed in the remaining 8 out of 14(57.1%). The expression of alpha-SMA was proven in perisinusoidal hepatic stellate cells, portal/septal myofibroblasts, and interface myofibroblasts. The degree of alpha-SMA expression and the number of alpha-SMA immunopositive cells were the most intensive in the liver with fibrosis. Desmin expression in all liver samples of infected sheep was confirmed in hepatic stellate cells and smooth muscle cells. The hepatic stellate cells, portal/septal myofibroblasts, and interface myofibroblasts reacted as vimentin positive cells. In the liver without fibrotic changes hepatic stellate cells and smooth muscle cells were desmin positive. The obtained results suggest that all populations of myofibroblasts, especially hepatic stellate cells, play an important role in the increased extracellular matrix formation during parasitic liver fibrosis in sheep naturally infected with D. dendriticum