Variation in pickleweed root-associated microbial communities at different locations of a saline solid waste management unit contaminated with petroleum hydrocarbons.

The main purpose of this study was to explore the potential influences of pickleweed vegetation on the abundance, diversity and metabolic activities of microbial communities in four distinct areas of a petroleum-contaminated solid waste management unit (SWMU) located in Contra Costa County, northern California. The four areas sampled include two central areas, one of which is central vegetated (CV) and one unvegetated (UV), and two peripheral vegetated areas, one of which is located to the west side of the SWMU (V-West) and one located to the east side (V-East). Measurements were made of total petroleum hydrocarbons (TPH), polyaromatic hydrocarbons (PAH), soil physicochemical properties, and various aspects of microbial communities including metabolic activities, microbial abundances (PLFAs), diversity and composition based on amplicon sequencing. The peripheral V-East and V-West sites had 10-times lower electrical conductivity (EC) than that of the CV and UV sites. The high salinity levels of the CV and UV sites were associated with significant reductions in bacterial and fungal abundances (PLFA) when compared to V-East but not when compared to V-West. TPH levels of CV and UV were not significantly different from those of V-West but were substantially lower than V-East TPH (19,311 mg/kg of dry soil), the high value of which may have been associated with a pipeline that ran through the area. Microbial activities (in terms of soil respiration and the activities of three soil enzymes, i.e., urease, lipase, and phosphatase) were greatest in the vegetated sites compared to the UV site. The prokaryotic community was not diverse as revealed by the Shannon index with no significant variation among the four groups of samples. However, the fungal community of the peripheral sites, V-East and V-West had significantly higher OTU richness and Shannon index. Structure of prokaryotic communities inhabiting the rhizosphere of pickleweed plants at the three sites differed significantly and were also different from those found in the UV region of the central site according to pairwise, global PERMANOVA and ANOSIM analyses. The differences in OTU-based rhizosphere-associated bacterial and fungal communities' composition were explained mainly by the changes in soil EC and pH. The results suggest that saline TPH-contaminated areas that are vegetated with pickleweed are likely to have increased abundances, diversity and metabolic activities in the rhizosphere compared to unvegetated areas, even in the presence of high salinity.

Quantitative histological study of duodenitis in biopsies.

In 48 patients, suffering from an endoscopically verified ulcerative or nonulcerative duodenitis, biopsies of the bulb and of the lower duodenum have been studied with quantitative histological methods. The evaluation of the data with simple and multivariate statistical methods revealed: In healthy duodenal mucosa the height of the villous epithelium significantly decreases with rising age, while the cellular infiltration of the stroma increases. Conclusive, sex dependent differences are not present. Many histological variables are significantly correlated to the endoscopical degree of inflammation, if the endoscopically normal mucosa of the lower duodenum is used as normal control. In contrast, the endoscopically normal bulb mucosa histologically showed inflammatory alterations in the majority of cases. As shown by a multivariate discriminant analysis, a correct histological diagnosis of duodenitis will be reached in nearly all patients, if a biopsy of the endoscopically normal lower duodenum of the same patients is used as matched control. As shown by a multiple stepwise regression analysis, the same procedure results in a good correspondence of the endoscopically estimated degree of inflammation and the values, calculated from histology. In some patients, the lower duodenum slightly takes part in the inflammation of the bulb. But no significant correlation was found between the calculated degree of inflammation of the bulb and of the lower duodenum, neither in ulcerative duodenitis nor in nonulcerative duodenitis. From a practical point of view, our findings elucidate, that the simultaneous histological examination of mucosa of the bulb and of endoscopically healthy mucosa of the lower duodenum will be an essential help in the diagnosis and grading of duodenitis and should be introduced as routine method.