Dysbiotic oral bacterial communities have a critical role in the etiology and progression of periodontal diseases. The goal of this study was to investigate the extent to which smoking increases risk for disease by influencing the composition of the subgingival microbiome in states of clinical health. Subgingival plaque samples were collected from 200 systemically and periodontally healthy smokers and nonsmokers. 16S pyrotag sequencing was preformed generating 1 623 713 classifiable sequences, which were compared with a curated version of the Greengenes database using the quantitative insights into microbial ecology pipeline. The subgingival microbial profiles of smokers and never-smokers were different at all taxonomic levels, and principal coordinate analysis revealed distinct clustering of the microbial communities based on smoking status. Smokers demonstrated a highly diverse, pathogen-rich, commensal-poor, anaerobic microbiome that is more closely aligned with a disease-associated community in clinically healthy individuals, suggesting that it creates an at-risk-for-harm environment that is primed for a future ecological catastrophe.

BackgroundThe number of tribes present within Bangladesh has been estimated to approximate one hundred and fifty. Information on traditional medicinal practices, particularly of the smaller tribes and their clans is lacking. It was the objective of the study to document the tribal medicinal practices of the Deb barma clan of the Tripura tribe, which clan can be found residing in Dolusora Tripura Palli of Moulvibazar district of Bangladesh. A further objective was to determine the extent of the community households who still prefer traditional treatment to other forms of treatment, particularly allopathic treatment.MethodsInterviews of the tribal healer and the tribal community regarding their ethnomedicinal practices were carried out with the help of a semi-structured questionnaire and the guided field-walk method. All together 67 clan members were interviewed including the Headman, tribal healer, 19 Heads of households and 46 other adult members of the clan. Information on number of members of household, their age, gender, educational status, occupation of working household members and preferred mode of treatment was obtained through the semi-structured questionnaire. In the guided field-walk method, the healer took the interviewers on field-walks through areas from where he collected his medicinal plants, pointed out the plants, and described their uses.ResultsThe clan had a total of 135 people distributed into 20 households and had only one traditional healer. Use of medicinal plants, wearing of amulets, and worship of the evil god ‘Bura debta’ constituted the traditional medicinal practices of the clan for treatment of diseases. The healer used a total of 44 medicinal plants distributed into 34 families for treatment of various ailments like pain, coughs, cold, gastrointestinal disorders, cuts and wounds, diabetes, malaria, heart disorders, and paralysis.ConclusionsAvailable scientific reports validate the use of a number of plants by the traditional healer. A number of the plants used by the clan healer had reported similar uses in Ayurveda, but differ considerably in their therapeutic uses from that reported for other tribes in Bangladesh. The present survey also indicated that in recent years the Deb barma clan members are inclining more towards allopathic medicine.

To our knowledge, fecal microbiota collection methods have not been evaluated in low-and middle-income countries. Therefore, we evaluated five different fecal sample collection methods for technical reproducibility, stability, and accuracy within the Health Effects of Arsenic Longitudinal Study (HEALS) in Bangladesh. Fifty participants from the HEALS provided fecal samples in the clinic which were aliquoted into no solution, 95% ethanol, RNAlater, postdevelopment fecal occult blood test (FOBT) cards, and fecal immunochemical test (FIT) tubes. Half of the aliquots were frozen immediately at Ϫ80°C (day 0) and the remaining samples were left at ambient temperature for 96 h and then frozen (day 4). Intraclass correlation coefficients (ICC) were calculated for the relative abundances of the top three phyla, for two alpha diversity measures, and for four beta diversity measures. The duplicate samples had relatively high ICCs for technical reproducibility at day 0 and day 4 (range, 0.79 to 0.99). The FOBT card and samples preserved in RNAlater and 95% ethanol had the highest ICCs for stability over 4 days. The FIT tube had lower stability measures overall. In comparison to the "gold standard" method using immediately frozen fecal samples with no solution, the ICCs for many of the microbial metrics were low, but the rank order appeared to be preserved as seen by the Spearman correlation. The FOBT cards, 95% ethanol, and RNAlater were effective fecal preservatives. These fecal collection methods are optimal for future cohort studies, particularly in low-and middle-income countries. IMPORTANCEThe collection of fecal samples in prospective cohort studies is essential to provide the opportunity to study the effect of the human microbiota on numerous health conditions. However, these collection methods have not been adequately tested in low-and middle-income countries. We present estimates of technical reproducibility, stability at ambient temperature for 4 days, and accuracy comparing a "gold standard" for fecal samples in no solution, 95% ethanol, RNAlater, postdevelopment fecal occult blood test cards, and fecal immunochemical test tubes in a study conducted in Bangladesh. Fecal occult blood test cards and fecal samples stored in 95% ethanol or RNAlater adequately preserve fecal samples in this setting. Therefore, new studies in low-and middle-income countries should include collection of fecal samples using fecal occult blood test cards, 95% ethanol, or RNAlater for prospective cohort studies.

Summary: Résumé: Zusammenfassung The allelopathic influence of four developmental stages of nodding thistle (small rosette, large rosette, bolting and dead plants) on eleven test species (six grasses, four legumes and itself) was investigated using aqueous extract bioassays, aqueous leachate bioassays, and bioassays based on addition of ground material to soil. The aqueous extract and leachate bioassays indicated that nodding thistle was most allelopathic at the rosette stages, while the bioassays involving amendment of soil with thistle tissue showed bolting live and dead plants to be the most allelopathic. It is proposed that nodding thistle is allelopathic at two phases of its development, i.e. at the early bolting stage when the larger rosette leaves are decomposing and releasing soluble inhibitors, and at the stage when bolting plants are dying and releasing insoluble inhibitors. Nodding thistle seedlings appear to be stimulated by addition of thistle tissues to soil, indicating that thistle plants may weaken pasture and simultaneously encourage recruitment of its own species. This is consistent with previous studies detecting high densities of thistle seedlings in the vicinity of deceased parent plants. The six grass species were generally more tolerant to thistle allelopathic effects than were the four legume species, but no consistent differences emerged between different grass or legume species. Influence de l'age de la plante sur le potentiel allélopathique du chardon penche (Carduus nutans L.) vis a vis des prairies de graminées et de légumineuses L'influence allélopathique de 4 stades de développement du chardon penché (petite rosette, grande rosette, montaison, plantes mortes) sur 11 espèces tests (6 graminées, 4 légumineuses et lui‐même) a étéétudiée en utilisant des bioessais d'extraction acqueuse, des bioessais de lessivage acqueux et des bioessais fondés sur l'addition au sol d'amendement. Les bioessais d'extraction acqueuse et de lessivage ont montré que le chardon penchéétait plus allélopathique au stade rosette tandis que les bioessais impliquant l'amendement de sol avec des tissues de chardon ont montré que la montaison et les plantes mortes étaient les plus allélopathiques. Il est proposé que le chardon penché est allélopathique à 2 phases de son développement, par exemple au stade montaison précoce quand les plus grandes feuilles de la rosette se décomposent et relachent les inhibiteurs solubles, et au stade où les plantes montées meurent et relächent les inhibiteurs insolubles. Les plantules de chardon penché apparaissent être stimulées par l'addition de tissus de chardon au sol, montrant que les plantes de chardon peuvent affaiblir une prairie et simultanément favoriser sa propre réimplantation. Ceci est conforme avec des études précédentes montrant des fortes densités de plantules de chardon au voisinage de plantes parentes mortes. Les 6 espèces de graminées ont été de façon générale plus tolérantes aux effets allélopathiques que les 4 espèces de légumineuses, mais aucune différence imp...

Carduus nutans L. is an invasive pasture/grassland species which may undergo rapid population growth through positive feedback. Plants of C. nutans produce a vegetative rosette, and after several months produce stems containing flower-heads, during which time the rosette leaves die and decompose. We investigated the influence of C. nutans on the nitrogen-fixation ability of Trifolium repens L. in three experiments. The first experiment was set up in a "mixture" design, and demonstrated that seedlings of T. repens were more susceptible to competition with other T. repens seedlings than to C. nutans seedlings. Nodule numbers and acetylene reduction per unit root, and acetylene reduction per unit nodules were adversely affected by increasing T. repens, but not C. nutansdensities. The second experiment was of an additive design, with separate partitions to isolate above-ground and belowground interference. Flowering C. nutans plants strongly inhibited T. repens root growth, nodulation and acetylene reduction, but usually only when shoot interference was permitted. This appears to be due to decomposition of rosette leaves, which was maximal at this stage. The third experiment involved monitoring effects of tagged C. nutans individuals against T. repens in the field. This experiment showed that acetylene reduction was severely influenced by flowering C. nutans (when rosette leaves were decomposing), even when only mild reduction of T. repens growth was observed, and these effects persisted for some months after the C. nutans plants had died. The results of these experiments in combination suggest that decomposing rosette leaves have a strong potential to inhibit T. repens nitrogen fixation. It appears that allelopathy is involved, since alternative explanations (e.g. root competition by C. nutans; effects of C. nutans on soil moisture, microbial nutrient immobilisation and light availability; facilitation of herbivores by C. nutans) can be effectively discounted. Although invasive species are often assumed to be associated with soil nitrogen build-up, we believe that some invasive species such as C. nutans have the potential to induce long-term decline of soil nitrogen input.