Can xenobiotics support the growth of Mn(II)-oxidizing bacteria (MnOB)? A case of phenol-utilizing bacteria Pseudomonas sp. AN-1

Biogenic manganese oxides (BioMnOx) produced by Mn(II)-oxidizing bacteria (MnOB) have garnered considerable attention for their exceptional adsorption and oxidation capabilities. However, previous studies have predominantly focused on the role of BioMnOx, neglecting substantial investigation into MnOB themselves. Meanwhile, whether the xenobiotics could support the growth of MnOB as the sole carbon source remains uncertain. In this study, we isolated a strain termed Pseudomonas sp. AN-1, capable of utilizing phenol as the sole carbon source. The degradation of phenol took precedence over the accumulation of BioMnOx. In the presence of 100 mg L-1 phenol and 100 µM Mn(II), phenol was entirely degraded within 20 h, while Mn(II) was completely oxidized within 30 h. However, at the higher phenol concentration (500 mg L-1), phenol degradation reduced to 32% and Mn(II) oxidation did not appear to occur. TOC determination confirmed the ability of strain AN-1 to mineralize phenol. Based on the genomic and proteomics studies, the Mn(II) oxidation and phenol mineralization mechanism of strain AN-1 was further confirmed. Proteome analysis revealed down-regulation of proteins associated with Mn(II) oxidation, including MnxG and McoA, with increasing phenol concentration. Notably, this study observed for the first time that the expression of Mn(II) oxidation proteins is modulated by the concentration of carbon sources. This work provides new insight into the interaction between xenobiotics and MnOB, thus revealing the complexity of biogeochemical cycles of Mn and C.

An apparatus for studying the response of cultured endothelial cells to stresses

In order to simulate the hemodynamic environment of human arteries in vivo, we designed a laminar flow apparatus which can precisely simulate the normal stress and shear stress to which cultured endothelial cells are exposed. Under both normal and abnormal physiological conditions, this apparatus can accurately control and adjust the values of normal stress and shear stress and the frequency of pulse waves, as well as the amplitude of pulsatile flow. This in vitro apparatus provides an experimental platform for studying the response of the biological characteristics of cultured endothelial cells in a hemodynamic environment.

[The effect of salvia miltiorrhiza and shengmai on inflammatory mediator and renal function of post-operative patients with obstructive jaundice]

OBJECTIVE

To investigate the effect of salvia miltiorrhiza and shengmai (SS) on inflammatory mediator and renal function in patients with obstructive jaundice (OJ).

METHODS

This study included three groups: the OJ patients receiving SS for 6 days after operation (the SS group, n = 15); the OJ patients not receiving SS (the OJ group, n = 15); the patients with other hepato-biliary disorders (the Non-OJ group, n = 15). The levels of ET, LPs, TNF-alpha, IL-6, IL-8 and urine RBP, TFR, ALB were measured one day before operation and 1, 4, 7 days after operation.

RESULTS

The SS group's LPs, TNF-alpha, IL-6, IL-8, ET, RBP, TFR and ALB levels were obviously lower on Day 7 after operation as compared with those on Day 1 after operation (P < 0.05). The urine RBP and ALB levels were significantly lower in the SS group than in the OJ group (P < 0.05).

CONCLUSION

The post-operative use of salvia miltiorrhiza and shengmai for patients with obstructive jaundice may effectively decrease the postoperative levels of plasma LPs, ET, TNF-alpha, IL-6 and IL-8. At the same time, salvia miltiorrhiza and shengmai may protect renal function by inhibiting inflammatory mediator and improving blood dynamics.

[Finite element analysis of pulsatile flow in aortic arch]

The blood flows in the ascending aorta and the aortic arch are studied. The theoretical models, boundary conditions and calculation conditions are proposed. The numerical simulation with finite element method of the blood flow in aortic arch of dogs is carried out according to the physiologically pulsatile flow conditions. The calculation results are analyzed with scientific visualization method.

[Value of intestinal decontamination by traditional Chinese medicine-X in the prevention of bacterial translocation complicated by severe acute pancreatitis in rats]

This study was designed to evaluate the efficacy of traditional Chinese Medicine-X in preventing the necrotic infection of the pancreas in severe acute pancreatitis (SAP). Sixty rats were randomly divided into five groups with 12 rats in each one: (1) normal control, (2) SAP + 0.9% normal saline (1 ml x 100 g-1 x 24 h-1), (3) SAP + gentamycin (2000 u x 100 g-1 x 24 h-1), (4) SAP + TCM-X (1.0 g x 100 g-1 x 24 h-1), and (5) SAP + gentamycin (2000 u x 100 g-1 x 24 h-1) + TCM-X (1.0 g x 100 g-1 x 24 h-1). The medicines were given by way of gastrotube, once every 24 hours, twice in all. Pancreatitis was induced by a single intraperitoneal injection of 500 mg.100 g-1 of L-arginine. Serum endotoxin were observed and the clone forming units from mesenteric lymphnode and pancreas were obtained after 48 hours treatment. 96 hours after the experiment, the bacteria found in the mesenteric lymphnodes and pancreas in groups three, four and five were reduced as compared to that in group two; the levels of serum endotoxin were reduced, too. These data indicate that TCM-X and gentamycin in decontamination by way of gastrotube are effective in preventing bacterial translocation complicated by SAP, and the effect of TCM-X is stronger than that of gentamycin.

[Theories of pulse wave in arteries]

This paper introduces the importance of studying pulse wave propagation and neviews the development process of the theories of pulse wave propagation. The main research achievements of nonlinear theories of pulse wave propagation are described, and the developing directions of studying pulse wave propagation are briefly stated.