Isolation and characterization of thermophilic benzothiophene-degrading Mycobacterium sp.

A bacterial strain, SWU-4, capable of using benzothiophene (BT) as a sole carbon and energy source was isolated from a petroleum-contaminated site in Thailand and identified by 16S rRNA gene sequence analysis to be in the genus of Mycobacterium. The strain was Gram-positive, nonspore former, and grew at 50° C. Colonies of the strain on nutrient agar were rod-shaped, smooth with a convex surface, slightly mucoid, and yellow pigmented. The thermophilic Mycobacterium sp. strain SWU-4 rapidly degraded 2% (w/v) BT at 50°C. Interestingly, this strain was able to degrade a wide variety of organosulfur compounds including thiophene, bromo(α)thiophene, and 3-methylthiophene in liquid minimum medium at 50°C, which will be beneficial for industrial applications.     

Natural Dietary Compound Xanthohumol Regulates the Gut Microbiota and Its Metabolic Profile in a Mouse Model of Alzheimer’s Disease

Discovering new and effective drugs for the treatment of Alzheimer’s disease (AD) is a major clinical challenge. This study focuses on chemical modulation of the gut microbiome in an established murine AD model. We used the 16S rDNA sequencing technique to investigate the effect of xanthohumol (Xn) on the diversity of intestinal microflora in 2-month- and 6-month-old APP/PS1 mice, respectively. APP/PS1 and wild-type mice were treated by gavage with corn oil with or without Xn every other day for 90 days. Prior to and following treatment, animals were tested for spatial learning, cognitive and memory function. We found Xn reduced cognitive dysfunction in APP/PS1 mice and significantly regulated the composition and abundance of gut microbiota both in prevention experiments (with younger mice) and therapeutic experiments (with older mice). Differential microflora Gammaproteobacteria were significantly enriched in APP/PS1 mice treated with Xn. Nodosilineaceae and Rikenellaceae may be the specific microflora modulated by Xn. The penicillin and cephalosporin biosynthesis pathway and the atrazine degradation pathway may be the principal modulation pathways. Taken together, oral treatment with Xn may have a neuroprotective role by regulating the composition of intestinal microflora, a result that contributes to the scientific basis for a novel prophylactic and therapeutic approach to AD.     

Binding of nontarget microorganisms from food washes to anti-<Emphasis Type="Italic">Salmonella</Emphasis> and anti-<Emphasis Type="Italic">E. coli</Emphasis> O157 immunomagnetic beads: most probable composition of background Eubacteria

We present herein the composition of bacterial communities occurring in ground chicken and the changes which arise in these populations based upon nonselective partitioning by commercially-available Dynal anti-Salmonella and anti-E. coli O157 immunomagnetic beads (IMB). Our enumeration and colony selection protocol was based upon a 6 × 6 drop plate method (n = 18 for each 25-g sub-sampling) using a dilution which resulted in ca. 4–8 colonies per drop. An average of 82 ± 13 colonies were selected from three 25-g ground chicken subsamplings per batch, each of which was repeated seasonally for one year. DNA was extracted from each colony and the composition of Eubacteria in each of these harvests was determined by sequence-based identification of 16S rDNA amplicons. The Gram-positive bacteria Brochothrix thermosphacta and Carnobacterium maltaromticum were the most commonly found organisms in both the total chicken wash (PBS) and in the IMB-bound (PBS-washed) fractions. The remaining background organisms which also adhered to varying degrees to commercial IMBs were: Pseudomonas oleovorans, Acinetobacter lwoffi, Serratia spp., and one Rahnella spp. A large number of the organisms were also cladistically evaluated based on rDNA basepair disparities: all Brochothrices were monophyletic; twelve different Pseudomonads were found along with eight Carnobacteria, seven Acinetobacteres, four Serratiae, and two Rahnellae. Carnobacterium alone showed an IMB-based concentration enhancement (ca. two to sixfold). Any reference to a brand or firm name does not constitute endorsement of the US Department of Agriculture over others of a similar nature not mentioned     

Isolation and characterization of 4-chlorophenol degrading bacterial strain from pharmaceutical xenobiotic compounds contaminated soil using enrichment technique

4- chlorophenol is available as the fundamental basic compound of numerous manufactured organics. It is produced from various sources like herbicides, wood additives, oil industries, pharmaceutical drugs and so on. It can be removed from the effluent by various ways but most effective method is bioremediation. In present study, aerobic bacterial strain was isolated from soil that was contaminated with pharmaceutical xenobiotic compounds using enrichment technique with 500 ppm of 4-chlorophenol as a sole source of carbon and energy. Colonies were isolated after 24 h of incubation on petri plate by media enrichment with 500 ppm of 4- chlorophenol and serial dilution method. 18 colonies were isolated and examined for their ability to degrade 500 ppm of 4-chlorophenol. The most potent strain, C17 was able to remove nearly ～99.93% of 4-chlorophenol in 24 h, 37 °C temperature and 6.8 pH. Based on morphological, biochemical, nucleotide homology and phylogenetic analysis the strain was found to have maximum similarity (98.98%) with Bacillus timonensis strain 10403023.     

Screening of fluorinated materials degrading microbes

Isolation of bacterial strains capable of degrading fluorinated materials was described. 8 strains of Actinobacteria exhibited degradability of ethyl difluoroacetate (DFAc) was accumulated by bacteria, giving difluoroacetic acid and then fluoride ion. Further, 13 strains of Actinobacteria exhibited degradability of fluorobenzene and/or benzotrifluoride. In batch culture, growth of strains on fluorinated materials led to the release of fluoride ion.     

山东威海海藻中细菌分离和多样性分析

从我国东部沿海城市威海金海滩(北纬36°41′～37°35′,东经121°11′～122°42′)采取海藻样品.采用可培分析方法得到55株菌.基于16SrDNA序列分析,发现这55株菌共分为5个纲,14个属.其中芽孢菌纲(Bacilli),γ-变形菌纲(Gammaproteobacteria)为优势种群,分别占总数的20%和56.4%.此外还分离获得2株具有琼胶降解活性的菌株,都属于海杆菌属(Marinimicrobium).部分菌株比已报道菌株相似度低,表明海藻样品具有较好的细菌多样性,并蕴藏着巨大的微生物资源.     

Whole-cell spectroscopy is a convenient tool to assist molecular identification of cultivatable marine bacteria and to investigate their adaptive metabolism

Recent developments in whole-cell spectroscopic methods allow rapid characterization of microorganisms of interest to human health, but have yet to be widely applied to marine microbiological studies. In this study of bacteria associated with the kelp Laminaria digitata, we have isolated 18 epiphytic bacterial strains from several thalli, sequenced their 16S rDNA, built corresponding phylogenetic trees, and characterized them using spectroscopic methods. Molecular taxonomy revealed Gram⁺Actinobacteria and Gram⁻Alphaproteobacteria, Gammaproteobacteria and Bacteroidetes. Twelve marine reference strains (Gram⁺Firmicutes, and Gram⁻Alphaproteobacteria, Gammaproteobacteria and Bacteroidetes) were treated accordingly. Whole-cell MALDI-TOF MS spectral profiles of 29 of the 30 strains were built into a database against which 16 replicate spectra of each strain were compared and categorized into groups. The proton HR-MAS NMR stack plots allowed visual delineation into taxonomic groups according to their most common peaks, in agreement with identifiable compounds from corresponding D₂O solution spectra. With both methods, these groups corresponded to taxa identified by 16S rDNA sequences, MALDI-TOF MS being more discriminative than HR-MAS NMR. Culture age did not influence the spectral signatures in both approaches. Most cells grown under minimal conditions (VNSS medium) afforded HR-MAS NMR profiles markedly different to those grown in enriched conditions (ZoBell medium), indicating different adaptive metabolic responses between the two media. Spectral signatures obtained under strictly controlled conditions can be used as rapid and reliable tools for taxonomic purposes and as markers of physiological status.     

稻属核糖体DNA的限制性片段长度多态性

对稻属13个种和Porteresiacoaretata、Leersiaperrieri及Leersiatisseranti共42份材料进行了核糖体RNA基因（rDNA）的间隔序列长度多态性（RFLP）的分析．共发现20种的间隔序列长度变异类型,其中有些类型具有种的特异性．中国药用野生稻的rDNA变异程度很小,疣粒野生稻的rDNA有变异．Leersiaperrieri和Leersiatisseranti的BamHI酶切转录区片段长度为3．90kb,与稻属的3．80kb．不同．     

Ganmaidazao decoction alleviated cognitive impairment on Alzheimer's disease rats by regulating gut microbiota and their corresponding metabolites

Traditional Chinese medicine targeted at gut microbiota has good effects in relieving the clinical manifestation of Alzheimer's disease, and intestinal metabolites are considered as a bridge of communication between the brain-gut axis. In order to explore the molecular mechanism of Ganmaidazao decoction treatment, first, the model rats induced by Aβ25-35 and d-gal were used to test the therapy of Ganmaidazao extract using the Morris Water Maze, Western Blot and Elisa. Then the 16S rDNA gene sequencing of the gut microbiota as well as UPLC-QTOF/MS-based metabolomic analysis of feces were carried out. Last, the relationship between Alzheimer's disease, gut microbiota and metabolites was analyzed. Results showed that the abundance and diversity of gut microbiota were rescued and the changes of fecal metabolites in rats with Alzheimer's disease were reversed after Ganmaidazao decoction administration, which were mainly related to lipid metabolism, steroid hormone metabolism, energy metabolism, amino acid metabolism and bile acid metabolism. After associating with Spearman’s correlation analysis, we concluded that gut microbiota and metabolites were closely related and Ganmaidazao decoction could interfere with the balance of gut microbiota and their corresponding metabolites to exert anti- Alzheimer’s disease effect. Combined with PICRUSt2 functional prediction of gut microbiota and metabolomics results, phenylalanine metabolism has been focused as a key metabolic pathway, and Ganmaidazao decoction can reduce the abnormal accumulation of phenylalanine and phenylpyruvate and promote their metabolism by restoring the activity of phenylalanine hydroxylase. This integrated omics approach has potential roles in understanding the complex mechanisms of Ganmaidazao decoction in treating Alzheimer’s disease.     

Electrochemical detection of E. coli 16S rDNA sequence using air-plasma-activated fullerene-impregnated screen printed electrodes

A new DNA modified electrode for the electrochemical detection of 16S rDNA extracted from Escherichia coli (JCM1649) is proposed. The electrodes were fabricated by screen printing a fullerene-impregnated carbon ink onto a poly(methylmethacrylate) substrate and immobilizing a probe DNA on the surface after activating the electrode with air plasma. The results indicated a dramatic improvement in the surface coverage of the immobilized probe DNA, and of the reduction peak of the redox indicator (Co(phen)(3)(3+)) due to the incorporation of fullerene. By immobilizing the probe onto the fullerene-impregnated screen-printed electrodes, the PCR product of the 16S rDNA extracted from E. coli was directly detected without any pretreatment. A well defined signal difference was observed between the perfectly matching oligonucleotide and the mismatching one, and it was possible to detect the target at the modified electrode. This method enabled us to clearly detect the two base mismatches in the ca. 1500-bases long 16S rDNA sequence.