Objective To explore the effect of lavender essential oil on the expression of brain-derived neurotrophic factor (BDNF)/pro-brain-derived neurotrophic factor (proBDNF) and the recovery of depression in the ischemic hippocampus of rats after stroke.&nbsp;<br>Methods A total of 45 male SD rats were randomly divided into a control group, a model group, and an intervention group, with 15 rats in each group. Rats in the control group raised under conventional conditions were subjected to intraperitoneal injection of physiological saline as a control experiment. In the model group, middle cerebral artery occlusion/reperfusion (MCAO/r) model was established and rats were given intraperitoneal injection of physiological saline. In the intervention group, rats were given lavender essential oil and exercise intervention after MCAO/r. The anxiety and depression behaviors of rats were tested through outdoor venues, forced swimming, and sucrose preference. The levels of oxidative stress biomarkers in rats were detected using commercial kits, and the expression of BDNF/proBDNF signaling pathway was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). The ratio of BDNF/proBDNF in CA1 region, CA3 region and dentategyrus (DG) regions of ischemic hippocampal tissue was analyzed by Western blotting (WB). The correlation analysis was performed between the BDNF/proBDNF ratio and behavioral tests for depression. Neurobehavioral (sensory and motor) testing was used to detect neural defects in rats.&nbsp;<br>〖MM(〗〖HT6SS〗〖CM10-8〗河北医科大学学报第44卷第11期〖MM)〗<br>Results The stationary time of the model group was longer than that of the control group, and the sucrose preference, climbing frequency, and exercise distance were lower than those of the control group. The static time of the intervention group was longer than that of the control group and shorter than that of the model group, while the sucrose preference, climbing frequency, and exercise distance were lower than those of the control group and higher than those of the model group (P＜0.05). The levels of superoxide dismutase (SOD), glutathione，r-glutamyl cysteingl + glycine (GSH) and fluoride resistant acid phosphatase (FRAP) in the model group were lower than those in the control group, and the levels of malondialdehyde (MDA) were higher than those in the control group. The levels of SOD, GSH and FRAP in the intervention group were higher than those in the model group, while the level of MDA was lower than that in the control group and the model group (P＜0.05). The mRNA expressions of BDNF, neurotrophic receptor (TrkB) and microtubule-associated protein (DCX) in the model group were lower than those in the control group, while the mRNA expressions of proBDNF and neurotrophic receptor P75 (p75NTR) were higher than those in the control group. The mRNA expressions of BDNF, TrkB, and DCX in the intervention group were lower than those in the control group and higher than those in the model group, while the mRNA expressions of proBDNF and p75NTR were higher than those in the control group but lower than those in the model group (P＜0.05). The BDNF/proBDNF ratio in the CA1, CA3, and DG regions of the model group was lower than that of the control group, which was higher in the intervention group than in the model group (P＜0.05). The BDNF/proBDNF ratio was negatively correlated with resting time during forced swimming (r=-0.74, P＜0.01), while the BDNF/proBDNF ratio was positively correlated with sucrose preference (r=0.63, P＜0.01). The neurological deficit score in the model group was higher than that in the control group, which was higher in the intervention group than in the control group and lower than that in the model group (P＜0.05). The expression of Bcl-2 related X protein (Bax)/B-cell lymphoma-2 gene (Bcl-2) in the model group was higher than that in the control group, while the expression of Bcl-2 was lower than that in the control group. The expression of Bax and Bax/Bcl-2 in the intervention group was lower than that in the model group, while the expression of Bcl-2 was higher than that in the model group (P＜0.05).&nbsp;<br>Conclusion Lavender essential oil may improve neurological function, enhance endogenous antioxidant defense, inhibit oxidative stress pathway and nerve apoptosis by regulating the relative level of BDNF and proBDNF, and then improve the depressive behavior of PSD rats.<br><div> <br></div>

Amplified marker-gene sequences can be used to understand microbial community structure, but they suffer from a high level of sequencing and amplification artifacts. The UPARSE pipeline reports operational taxonomic unit (OTU) sequences with ≤1% incorrect bases in artificial microbial community tests, compared with >3% incorrect bases commonly reported by other methods. The improved accuracy results in far fewer OTUs, consistently closer to the expected number of species in a community.

We evaluate the substantial amount of information accumulated on bacterial diversity in a variety of environments and address several fundamental questions, focusing on aquatic systems but including other environments to provide a broader context. Bacterial diversity data were extracted from 225 16S rDNA libraries described in published reports, representing a variety of aquatic and non-aquatic environments. Libraries were predominantly composed of rare phylotypes that appeared only once or twice in the library, and the number of phylotypes observed was correlated with library size (implying that few libraries are exhaustive samples of diversity in the source community). Coverage, the estimated proportion of phylotypes in the environment represented in the library, ranged widely but on average was remarkably high and not correlated with library size. Phylotype richness was calculated by methods based on the frequency of occurrence of different phylotypes in 194 libraries that provided appropriate data. For 90% of aquatic-system libraries, and for 79% of non-aquatic libraries, the estimated phylotype richness was <200 phylotypes. Nearly all of the larger estimates were in aquatic sediments, digestive systems and soils. However, the approaches used to estimate phylotype richness may yield underestimates when libraries are too small. A procedure is described to provide an objective means of determining when a library is large enough to provide a stable and unbiased estimate of phylotype richness. A total of 56 libraries, including 44 from aquatic systems, were considered 'large enough' to yield stable estimates suitable for comparing richness among environments. Few significant differences in phylotype richness were observed among aquatic environments. For one of two richness estimators, the average phylotype richness was significantly lower in hyperthermal environments than in sediment and bacterioplankton, but no other significant differences among aquatic environments were observed. In general, and with demonstrated exceptions, published studies have captured a large fraction of bacterial diversity in aquatic systems. In most cases, the estimated bacterial diversity is lower than we would have expected, although many estimates should be considered minimum values. We suggest that on local scales, aquatic bacterial diversity is much less than any predictions of their global diversity, and remains a tractable subject for study. The global-scale diversity of aquatic Bacteria, on the other hand, may be beyond present capabilities for effective study.

This article describes the composition of root exudates, how these metabolites are released to the rhizosphere and their importance in the recruitment of beneficial microbiota that alleviate plant stress. Metabolites secreted to the rhizosphere by roots are involved in several processes. By modulating the composition of the root exudates, plants can modify soil properties to adapt and ensure their survival under adverse conditions. They use several strategies such as (1) changing soil pH to solubilize nutrients into assimilable forms, (2) chelating toxic compounds, (3) attracting beneficial microbiota, or (4) releasing toxic substances for pathogens, etc. In this work, the composition of root exudates as well as the different mechanisms of root exudation have been reviewed. Existing methodologies to collect root exudates, indicating their advantages and disadvantages, are also described. Factors affecting root exudation have been exposed, including physical, chemical, and biological agents which can produce qualitative and quantitative changes in exudate composition. Finally, since root exudates play an important role in the recruitment of mycorrhizal fungi and plant growth-promoting rhizobacteria (PGPR), the mechanisms of interaction between plants and the beneficial microbiota have been highlighted.

The number of prokaryotes and the total amount of their cellular carbon on earth are estimated to be 4-6 x 10(30) cells and 350-550 Pg of C (1 Pg = 10(15) g), respectively. Thus, the total amount of prokaryotic carbon is 60-100% of the estimated total carbon in plants, and inclusion of prokaryotic carbon in global models will almost double estimates of the amount of carbon stored in living organisms. In addition, the earth's prokaryotes contain 85-130 Pg of N and 9-14 Pg of P, or about 10-fold more of these nutrients than do plants, and represent the largest pool of these nutrients in living organisms. Most of the earth's prokaryotes occur in the open ocean, in soil, and in oceanic and terrestrial subsurfaces, where the numbers of cells are 1.2 x 10(29), 2.6 x 10(29), 3.5 x 10(30), and 0. 25-2.5 x 10(30), respectively. The numbers of heterotrophic prokaryotes in the upper 200 m of the open ocean, the ocean below 200 m, and soil are consistent with average turnover times of 6-25 days, 0.8 yr, and 2.5 yr, respectively. Although subject to a great deal of uncertainty, the estimate for the average turnover time of prokaryotes in the subsurface is on the order of 1-2 x 10(3) yr. The cellular production rate for all prokaryotes on earth is estimated at 1.7 x 10(30) cells/yr and is highest in the open ocean. The large population size and rapid growth of prokaryotes provides an enormous capacity for genetic diversity.

Soil microbial communities are crucial in maintaining the functions of wetland ecosystems. Understanding the microbial community structure and the key factors driving the assemblages of wetland soil microbiota are important to reveal the connections between microorganisms and functions of wetland ecosystems. In this study, soil bacterial community compositions and the factors shaping them were investigated in three groups of wetlands across China, including Tibet plateau wetlands (TW), inland wetlands (IW) and coastal wetlands (CW). Overall, Bacterial community structure and turnover showed distinct patterns in different groups. Bacterial phyla were mainly composed of Proteobacteria followed by Chloroflexi, Acidobacteria, Actinobacteria and Bacteroidetes in all groups of wetland samples. At genus level, random forest model showed that Coprothermobacter and Acetobacter were two most important genera explaining the differences among groups. The abundances of these genera were very low in IW relative to the other two groups. The alpha diversity of IW was significantly higher than those of TW and CW. The relative contribution of environmental factors was larger in the assemblages of bacterial communities in TW and CW than that in IW. The pH and conductivity were recognized as the most important measured environmental factors influencing bacterial community structure. Our results suggested that the bacterial communities of wetlands in different regions were shaped with different mechanisms. The communities in CW and TW regions owned lower alpha diversity and were more influenced by deterministic processes than those in IW. In conclusion, the spatial pattern of soil bacterial community assembly in Chinese wetland was scale-dependent.

Permafrost wetlands are important methane emission sources and fragile ecosystems sensitive to climate change. Presently, there remains a lack of knowledge regarding bacterial communities, especially methanotrophs in vast areas of permafrost on the Tibetan Plateau in Northwest China and the Sanjiang Plain (SJ) in Northeast China. In this study, 16S rRNA-based quantitative PCR (qPCR) and 454 pyrosequencing were used to identify bacterial communities in soils sampled from a littoral wetland of Lake Namco on the Tibetan Plateau (NMC) and an alluvial wetland on the SJ. Additionally, methanotroph-specific primers targeting particulate methane monooxygenase subunit A gene (pmoA) were used for qPCR and pyrosequencing analysis of methanotrophic community structure in NMC soils. qPCR analysis revealed the presence of 10(10) 16S rRNA gene copies per gram of wet soil in both wetlands, with 10(8) pmoA copies per gram of wet soil in NMC. The two permafrost wetlands showed similar bacterial community compositions, which differed from those reported in other cold environments. Proteobacteria, Actinobacteria, and Chloroflexi were the most abundant phyla in both wetlands, whereas Acidobacteria was prevalent in the acidic wetland SJ only. These four phyla constituted more than 80 % of total bacterial community diversity in permafrost wetland soils, and Methylobacter of type I methanotrophs was overwhelmingly dominant in NMC soils. This study is the first major bacterial sequencing effort of permafrost in the NMC and SJ wetlands, which provides fundamental data for further studies of microbial function in extreme ecosystems under climate change scenarios.

Northern peatlands represent a major global carbon store harbouring approximately one-third of the global reserves of soil organic carbon. A large proportion of these peatlands consists of acidic Sphagnum-dominated ombrotrophic bogs, which are characterized by extremely low rates of plant debris decomposition. The degradation of cellulose, the major component of Sphagnum-derived litter, was monitored in long-term incubation experiments with acidic (pH 4.0) peat extracts. This process was almost undetectable at 10°C and occurred at low rates at 20°C, while it was significantly accelerated at both temperature regimes by the addition of available nitrogen. Cellulose breakdown was only partially inhibited in the presence of cycloheximide, suggesting that bacteria participated in this process. We aimed to identify these bacteria by a combination of molecular and cultivation approaches and to determine the factors that limit their activity in situ. The indigenous bacterial community in peat was dominated by Alphaproteobacteria and Acidobacteria. The addition of cellulose induced a clear shift in the community structure towards an increase in the relative abundance of the Bacteroidetes. Increasing temperature and nitrogen availability resulted in a selective development of bacteria phylogenetically related to Cytophaga hutchinsonii (94-95% 16S rRNA gene sequence similarity), which densely colonized microfibrils of cellulose. Among isolates obtained from this community only some subdivision 1 Acidobacteria were capable of degrading cellulose, albeit at a very slow rate. These Acidobacteria represent indigenous cellulolytic members of the microbial community in acidic peat and are easily out-competed by Cytophaga-like bacteria under conditions of increased nitrogen availability. Members of the phylum Firmicutes, known to be key players in cellulose degradation in neutral habitats, were not detected in the cellulolytic community enriched at low pH.© 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Biological control of soil-borne pathogens comprises the decrease of inoculum or of the disease producing activity of a pathogen through one or more mechanisms. Interest in biological control of soil-borne plant pathogens has increased considerably in the last few decades, because it may provide control of diseases that cannot or only partly be managed by other control strategies. Recent advances in microbial and molecular techniques have significantly contributed to new insights in underlying mechanisms by which introduced bacteria function. Colonization of plant roots is an essential step for both soil-borne pathogenic and beneficial rhizobacteria. Colonization patterns showed that rhizobacteria act as biocontrol agents or as growth-promoting bacteria form microcolonies or biofilms at preferred sites of root exudation. Such microcolonies are sites for bacteria to communicate with each other (quorum sensing) and to act in a coordinated manner. Elicitation of induced systemic resistance (ISR) by plant-associated bacteria was initially demonstrated using Pseudomonas spp. and other Gram-negative bacteria. Several strains of the species Bacillus amyloliquefaciens, B. subtilis, B. pasteurii, B. cereus, B. pumilus, B. mycoides, and B. sphaericus elicit significant reductions in the incidence or severity of various diseases on a diversity of hosts. Elicitation of ISR by these strains has been demonstrated in greenhouse or field trials on tomato, bell pepper, muskmelon, watermelon, sugar beet, tobacco, Arabidopsis sp., cucumber, loblolly pine, and two tropical crops (long cayenne pepper and green kuang futsoi). Protection resulting from ISR elicited by Bacillus spp. has been reported against leaf-spotting fungal and bacterial pathogens, systemic viruses, a crown-rotting fungal pathogen, root-knot nematodes, and a stem-blight fungal pathogen as well as damping-off, blue mold, and late blight diseases. This progress will lead to a more efficient use of these strains which is worthwhile approach to explore in context of biocontrol strategies.

不动杆菌属是目前导致医院感染的常见细菌且耐药率很高,引起广泛关注。自1911年不动杆菌被分离鉴定以来,不动杆菌种属的分类和命名一直处于不断更新的状态。早期依据不动杆菌形态学和生化表型特征进行种属鉴定,但识别精度不高,经常出现菌种被错误鉴定的情况。随着分子生物学技术的发展,不动杆菌属的菌种可以通过全基因组测序技术被精确地鉴定和区分,这为深入研究不动杆菌的毒力和致病性差异提供了有力的支撑。本文对不动杆菌的分类历史和研究现状进行综述。

Acinetobacter is a common bacterium that causes nosocomial infection at present, and the drug resistance rate is very high. Since the isolation and identification of Acinetobacter in 1911, the classification and naming of Acinetobacter species have been constantly updated.Early species identification based on morphological and biochemical phenotypic characteristics of acinetobacter was carried out, but the identification accuracy was not high, and the species were often wrongly identified. With the development of molecular biology technology, Acinetobacter species can be accurately identified and distinguished by whole genome sequencing technology, which provides a strong support for the in-depth study of the virulence and pathogenicity differences of Acinetobacter. This paper reviews the classification history and research status of Acinetobacter.

In this work, pH-responsive gel spheres for controlled release of humic acid (CSGCHs) were prepared by an integrated instillation technology using a composite material of sodium alginate (SA) and charcoal activated carbon (CAC) as a carrier, and their slow-release performance, pH-responsive performance, and soil amendment performance were investigated. The results showed that the prepared CSGCH was uniform in size with obvious base responsiveness. Soil remediation experiments revealed that CSGCH could play a good role in the remediation of different types of soils. After 50 days of remediation, the content of nutrients and organic matter in the soil increased significantly and the pH and salt content of saline soils decreased by 15.2 and 29.8%, respectively. The plant experiment showed that CSGCH could effectively promote the growth of crops. Therefore, the prepared soil conditioner has a great potential value for improving soil conditions and promoting crop growth in agricultural applications.