Kartchner Caverns in Benson, AZ, was opened for tourism in 1999 after a careful development protocol that was designed to
maintain predevelopment conditions. As a part of an ongoing effort to determine the impact of humans on this limestone cave,
samples were collected from cave rock surfaces along the cave trail traveled daily by tour groups (200,000 visitors year–1) and compared to samples taken from areas designated as having medium (30–40 visitors year–1) and low (2–3 visitors year–1) levels of human exposure. Samples were also taken from fiberglass moldings installed during cave development. Culturable
bacteria were recovered from these samples and 90 unique isolates were identified by using 16S rRNA polymerase chain reaction
and sequencing. Diversity generally decreased as human impact increased leading to the isolation of 32, 27, and 22 strains
from the low, medium, and high impact areas, respectively. The degree of human impact was also reflected in the phylogeny
of the isolates recovered. Although most isolates fell into one of three phyla: Actinobacteria, Firmicutes, or Proteobacteria,
the Proteobacteria were most abundant along the cave trail (77% of the isolates), while Firmicutes predominated in the low
(66%) and medium (52%) impact areas. Although the abundance of Proteobacteria along the cave trail seems to include microbes
of environmental rather than of anthropogenic origin, it is likely that their presence is a consequence of increased organic
matter availability due to lint and other organics brought in by cave visitors. Monitoring of the cave is still in progress
to determine whether these bacterial community changes may impact the future development of cave formations. 相似文献
A vibrio-like bacterium, designated Vibrio sp. (BML 79-078), was isolated from moribund juvenile Amercan lobsters, Homarus americanus. This is the first report of a vibrio-like bacterium being associated with a disease of lobsters. Koch's postulates have been satisfied for this bacterium. In this study, Vibrio sp. (BML 79-078) and Vibrio anguillarum (ATCC 19264) were found to be pathogenic when injected into juvenile lobsters held at 20°C, while Enterobacter aerogenes was not. An endotoxin was found to be associated with the pathogenesis of the disease syndrome caused by Vibrio sp. (BML 79-087). 相似文献
Candida can be implicated in the pathology of chronic periodontitis.
Aims
To analyze the oral Candida carriage in patients suffering from chronic periodontitis (CP) and its correlation with the severity of this condition.
Methods
Microbiological samples were taken from 155 patients using the oral rinse (OR) technique and by using paper points in the periodontal pockets (GPP). These patients were divided into 3 groups: 89 patients without CP (control), 47 with moderate CP, and 19 with severe CP. Samples were cultured in a Candida chromogenic agar for Candida. Species were identified by microbiological and molecular methods.
Results
Candida was isolated in the OR of 45 (50.6%), 21 (44.7%), and 11 (57.9%) patients, respectively, and in the GPP of 32 (36%), 14 (29.2%), and 10 (42.6%) patients from the control, moderate CP and severe CP groups, respectively. Candida was isolated more frequently and in a greater burden in OR than in GPP (p < 0.01). Candida albicans was the most prevalent species. GPP of patients with CP had poor fungal biodiversity (p < 0.01).
Conclusions
Colonization by Candida was present in the samples of patients without CP, and with both moderate and severe CP. Nonetheless, patients with severe CP had a higher rate of Candida colonization, especially by C. albicans. 相似文献
Neutrophils and monocytes play an important role in overt inflammation in chronic inflammatory joint diseases such as rheumatoid
arthritis (RA). The sympathetic nervous system (SNS) inhibits many neutrophil/monocyte functions and macrophage tumor necrosis
factor (TNF), but because of the loss of sympathetic nerve fibers in inflamed tissue, sympathetic control is attenuated. In
this study, we focused on noradrenergic and TNF regulation of human neutrophil peptides 1-3 (HNP1-3), which are proinflammatory
bactericidal α-defensins. 相似文献
Climate warming is supposed to enlarge the area climatically suitable to the naturalization of alien garden plants in temperate regions. However, the effects of a changing climate on the spread of naturalized ornamentals have not been evaluated by spatially and temporarily explicit range modelling at larger scales so far. Here, we assess how climate change and the frequency of cultivation interactively determine the spread of 15 ornamental plants over the 21st century in Europe. We coupled species distribution modelling with simulations of demography and dispersal to predict range dynamics of these species in annual steps across a 250 × 250 m raster of the study area. Models were run under four scenarios of climate warming and six levels of cultivation intensity. Cultivation frequency was implemented as size of the area used for planting a species. Although the area climatically suitable to the 15 species increases, on average, the area predicted to be occupied by them in 2090 shrinks under two of the three climate change scenarios. This contradiction obviously arises from dispersal limitations that were pronounced although we assumed that cultivation is spatially adapting to the changing climate. Cultivation frequency had a much stronger effect on species spread than climate change, and this effect was non‐linear. The area occupied increased sharply from low to moderate levels of cultivation intensity, but levelled off afterwards. Our simulations suggest that climate warming will not necessarily foster the spread of alien garden plants in Europe over the next decades. However, climatically suitable areas do increase and hence an invasion debt is likely accumulating. Restricting cultivation of species can be effective in preventing species spread, irrespective of how the climate develops. However, for being successful, they depend on high levels of compliance to keep propagule pressure at a low level. 相似文献
A fructose-rich diet can induce metabolic syndrome, a combination of health disorders that increases the risk of diabetes and cardiovascular diseases. Diet is also known to alter the microbial composition of the gut, although it is not clear whether such alteration contributes to the development of metabolic syndrome. The aim of this work was to assess the possible link between the gut microbiota and the development of diet-induced metabolic syndrome in a rat model of obesity. Rats were fed either a standard or high-fructose diet. Groups of fructose-fed rats were treated with either antibiotics or faecal samples from control rats by oral gavage. Body composition, plasma metabolic parameters and markers of tissue oxidative stress were measured in all groups. A 16S DNA-sequencing approach was used to evaluate the bacterial composition of the gut of animals under different diets. The fructose-rich diet induced markers of metabolic syndrome, inflammation and oxidative stress, that were all significantly reduced when the animals were treated with antibiotic or faecal samples. The number of members of two bacterial genera, Coprococcus and Ruminococcus, was increased by the fructose-rich diet and reduced by both antibiotic and faecal treatments, pointing to a correlation between their abundance and the development of the metabolic syndrome. Our data indicate that in rats fed a fructose-rich diet the development of metabolic syndrome is directly correlated with variations of the gut content of specific bacterial taxa. 相似文献
Coenzyme Q10 (CoQ10) is the main CoQ species in human and is used extensively in food, cosmetic and medicine industries because of its antioxidant properties and its benefit in prophylactic medicine and therapy for a variety of diseases. Among various approaches to increase the production of CoQ10, microbial fermentation is the most effective. As knowledge of the biosynthetic enzymes and regulatory mechanisms modulating CoQ10 production increases, opportunities arise for metabolic engineering of CoQ10 in microbial hosts. In this review, we present various strategies used up to date to improve CoQ10 production and focus on metabolic engineering of CoQ10 overproduction in microbes. General strategies of metabolic engineering include providing sufficient precursors for CoQ10, increasing metabolic fluxes, and expanding storage capacity for CoQ10. Based on these strategies, CoQ10 production has been significantly improved in natural CoQ10 producers, as well as in heterologous hosts.
Hydrobiologia - Integrative approaches are particularly useful to resolve taxonomic uncertainties in species-rich groups that have undergone explosive radiation, such as Hypostomini (suckermouth... 相似文献
Nω-nitro-L-arginine methyl ester (L-NAME) treatment induces arteriosclerosis and vascular senescence. Here, we report that the systemic inhibition of nitric oxide (NO) production by L-NAME causes pulmonary emphysema. L-NAME-treated lungs exhibited both the structural (alveolar tissue destruction) and functional (increased compliance and reduced elastance) characteristics of emphysema development. Furthermore, we found that L-NAME-induced emphysema could be attenuated through both genetic deficiency and pharmacological inhibition of plasminogen activator inhibitor-1 (PAI-1). Because PAI-1 is an important contributor to the development of senescence both in vitro and in vivo, we investigated whether L-NAME-induced senescence led to the observed emphysematous changes. We found that L-NAME treatment was associated with molecular and cellular evidence of premature senescence in mice, and that PAI-1 inhibition attenuated these increases. These findings indicate that NO serves to protect and defend lung tissue from physiological aging. 相似文献