Effect of the bacterial community assembly process on the microbial remediation of petroleum hydrocarbon-contaminated soil.

Introduction: The accumulation of petroleum hydrocarbons (PHs) in the soil can reduce soil porosity, hinder plant growth, and have a serious negative impact on soil ecology. Previously, we developed PH-degrading bacteria and discovered that the interaction between microorganisms may be more important in the degradation of PHs than the ability of exogenous-degrading bacteria. Nevertheless, the role of microbial ecological processes in the remediation process is frequently overlooked. Methods: This study established six different surfactant-enhanced microbial remediation treatments on PH-contaminated soil using a pot experiment. After 30 days, the PHs removal rate was calculated; the bacterial community assembly process was also determined using the R language program, and the assembly process and the PHs removal rate were correlated. Results and discussion: The rhamnolipid-enhanced Bacillus methylotrophicus remediation achieved the highest PHs removal rate, and the bacterial community assembly process was impacted by deterministic factors, whereas the bacterial community assembly process in other treatments with low removal rates was affected by stochastic factors. When compared to the stochastic assembly process and the PHs removal rate, the deterministic assembly process and the PHs removal rate were found to have a significant positive correlation, indicating that the deterministic assembly process of bacterial communities may mediate the efficient removal of PHs. Therefore, this study recommends that when using microorganisms to remediate contaminated soil, care should be taken to avoid strong soil disturbance because directional regulation of bacterial ecological functions can also contribute to efficient removal of pollutants.

Clinical manifestation and treatment of small intestinal lymphangioma: A single center analysis of 15 cases.

Background: Small intestinal lymphangioma is a very rare benign lesion. Thus far, the literature on small intestinal lymphangioma has mainly involved case reports. The present study retrospectively examined the clinical features of patients with a pathological diagnosis of small intestinal lymphangioma. Materials and methods: From January 2010 to January 2021, 15 patients were pathologically diagnosed with small intestinal lymphangioma. The age, gender, clinical manifestation, computed tomography (CT) findings, endoscopic findings, localization of the lesion, treatment method, complications, and follow-up were retrospectively analyzed. Results: Most of the patients had no symptoms, and those with symptoms had melena or abdominal pain. Lymphangioma was located in the duodenum in nine cases (60.0%), jejunum in two (13.3%), jejunal-ileal junction with mesentery involvement in one (6.7%) and ileum in three (20.0%). Three cases (20.0%) had multiple lesions, and the other 12 (80.0%) had single lesions. The median size of the lesions was 0.8 cm. Thirteen cases were found by endoscopy, and nine cases of them had white-colored spots on the surface. Ten cases (66.7%) underwent endoscopic treatment, three (20.0%) underwent surgical treatment, and two (13.3%) were followed up. Postoperative acute pancreatitis developed in one patient after endoscopic resection of duodenal papillary lymphangioma; postoperative abdominal bleeding occurred in one patient with jejunal lymphangioma who underwent partial small bowel resection. Conclusion: Small intestinal lymphangioma is extremely rare, and its clinical manifestations are non-specific. Endoscopy is of great value in the diagnosis of small intestinal lymphangioma. Depending on the clinical manifestations, the size, location and scope of the lesions, follow-up, endoscopic treatment and surgery can be selected.

Organo-mineral complexes alter bacterial composition and induce carbon and nitrogen cycling in the rhizosphere.

It is widely thought that organo-mineral complexes (OMCs) stabilize organic matter via mineral adsorption. Recent studies have demonstrated that root exudates can activate OMCs, but the influence of OMCs on plant rhizosphere, which is among the most active areas for microbes, has not been thoroughly researched. In this study, a pot experiment using Brassica napus was conducted to investigate the effects of OMCs on plant rhizosphere. The result showed that OMC addition significantly promoted the growth of B. napus compared to the prevalent fertilization (PF, chemical fertilizer + chicken compost) treatment. Specifically, OMC addition increased the relative abundance (RA) of nitrogen-fixing bacteria and the bacterial α-diversity, and the operational taxonomic unit (OTU) group with RA > 0.5% in the OMC-treated rhizosphere was the result of a deterministic assembly process with homogeneous selection. Gene abundance related to nitrogen cycling and the soil chemical analysis demonstrated that the OMC-altered bacterial community induced nitrogen fixation and converted nitrate to ammonium. The upregulated carbon sequestration pathway genes and the increased soil microbial biomass carbon (23.68%) demonstrated that the bacterial-induced carbon storage in the rhizosphere was activated. This study shows that the addition of OMCs can influence the biogeochemical carbon and nitrogen cycling via regulating microorganisms in the rhizosphere. The findings provide fresh insights into the effects of OMCs on the biogeochemical cycling of important elements and suggest a promising strategy for improving soil productivity.

Activating soil microbial community using bacillus and rhamnolipid to remediate TPH contaminated soil.

Soil petroleum contamination has become a global environmental problem. In order to develop a new soil remediation technology, this study established bacteria isolation, surfactant toxicity matching and petroleum contaminated soil remediation practice. The simulated field remediation showed that inoculating the soil with Bacillus methylotrophicus and adding 500 mg kg-1 rhamnolipid (N + RL) to soil can remove 80.24% of aged total petroleum hydrocarbons (TPHs) within 30 days. In particular, although the remediated soil has inoculated sufficient bacterial suspension, the microbial abundance of Bacillus was not a significantly dominant genus after remediation, especially in N + RL (0.73% of the total), but the colonies of indigenous petroleum-degrading bacteria (such as Massilia and Streptomyces) increased significantly. The interaction among genera has been further proved to drive soil non-specific oxidases (such as polyphenol oxidase, laccase and catalase) to remove TPHs. This indicates that the interaction among microorganisms, rather than the degradability of exogenous degrading bacteria, plays more critical role in the degradation of organic pollutants, which enriches the traditional understanding of micro-remediation of contaminated soil. It can be concluded from the obtained results that the remediation of pollutants can be achieved by adjusting the purification capacity of the microbial community and the natural environment.

A case of multiple macronodular hepatic tuberculosis difficult to differentiate from hepatocellular carcinoma with intrahepatic metastasis: CT-guided fine needle aspiration biopsy confirmed the diagnosis.

Multiple macronodular hepatic tuberculosis is difficult to be differentiated from hepatocellular carcinoma with intrahepatic metastasis in clinical practice, especially when hepatitis B with or without liver cirrhosis coexists with it. Herein, we report a 30-year-old man with a 10-year history of hepatitis B and a family medical history of hepatocellular carcinoma related with hepatitis B that was finally diagnosed as multiple macronodular hepatic tuberculosis. Abdominal B-mode ultrasonography (US) and plain computed tomography (CT) revealed multiple unequal-sized nodules in the liver. CT-guided fine needle aspiration biopsy (FNAB) of the liver demonstrated a caseating granuloma with lymphocytes, multinucleate giant cells and epithelioid cells compatible with the diagnosis of tuberculosis and no hepatoma cells were detected. Thus, the diagnosis of hepatic tuberculosis was confirmed and hepatocellular carcinoma with intrahepatic metastasis was excluded.