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Characteristics and living patterns of marine myxobacterial isolates.

ABSTRACT: The growth, morphology, and life cycle of two marine myxobacterial isolates, halotolerant Myxococcus fulvus strain HW-1 and halophilic Haliangium ochraceum strain SMP-2, were studied as models to determine the living patterns of myxobacteria in the ocean. The growth, morphology, and development of halotolerant strain HW-1 shifted in response to salinity. The optimal seawater concentration for growth of HW-1 was 0 to 80% (salinity, 0.1 to 2.9%), and the strain grew poorly in media with a salinity of more than 4%. The cells became shorter as the seawater concentration increased. The fruiting body structure was complete only on agar prepared with low concentrations of seawater or salts (less than 60% seawater; salinity, 2.1%), and rudimentary structures or even simple cell mounds appeared as the seawater concentration increased. In contrast, the halophilic strain SMP-2 was unable to grow without NaCl. The cell length and the morphology of the fruiting body-like structure did not change in response to salts. In seawater liquid medium, the cells of both strains were confirmed to be able to form myxospores directly from vegetative cells, but they could not do so in medium containing a low seawater concentration (10% or less). HW-1 cells from medium containing a high concentration of seawater grew independent of cell density, while cells from medium containing a low concentration of seawater (10% or less) showed density-dependent growth. SMP-2 cells showed density-dependent growth under all salinity conditions. The results suggest that the halotolerant myxobacteria are the result of degenerative adaptation of soil myxobacteria to the marine environment, while the halophilic myxobacteria form a different evolutionary group that is indigenous to the ocean.

SUBMITTER: Zhang YQ

PROVIDER: S-EPMC1151793 | biostudies-literature | 2005 Jun

REPOSITORIES: biostudies-literature

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Characteristics and living patterns of marine myxobacterial isolates.

Zhang Yu-Qing YQ Li Yue-Zhong YZ Wang Bing B Wu Zhi-Hong ZH Zhang Cui-Ying CY Gong Xun X Qiu Zhi-Jun ZJ Zhang Yong Y

Applied and environmental microbiology 20050601 6

The growth, morphology, and life cycle of two marine myxobacterial isolates, halotolerant Myxococcus fulvus strain HW-1 and halophilic Haliangium ochraceum strain SMP-2, were studied as models to determine the living patterns of myxobacteria in the ocean. The growth, morphology, and development of halotolerant strain HW-1 shifted in response to salinity. The optimal seawater concentration for growth of HW-1 was 0 to 80% (salinity, 0.1 to 2.9%), and the strain grew poorly in media with a salinity ...[more]

PMID: 15933036

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Project description:BackgroundMetabolic diseases, including obesity and type 2 diabetes, are a major health concern for Latina immigrants. Performing regular aerobic physical activity (PA) is a lifestyle behavior associated with the prevention and control of these conditions. However, PA levels of most Latina immigrants are below national guidelines. Neighborhood environmental factors may influence the PA levels of adults, but limited research has explored associations between the neighborhood environment and PA levels among Latina immigrants.ObjectiveThe objective of this study was to explore the PA patterns of first-generation US Latina immigrants and how neighborhood environmental factors are related to those PA patterns.MethodsUsing a cross-sectional study design, 50 first-generation Latina immigrants completed the International Physical Activity Questionnaire (IPAQ) and the Neighborhood Scales Questionnaire, which assessed 6 perceived neighborhood factors: (1) walking environment, (2) aesthetic quality, (3) safety, (4) violence, (5) social cohesion, and (6) activities with neighbors. Median self-reported metabolic equivalent (MET)-minutes/week of PA were used to summarize domain-specific (ie, work, domestic/household, leisure, and transportation) and intensity-specific (ie, walking, moderate, vigorous, moderate to vigorous) PA patterns. Logistic regression examined associations between neighborhood factors and engaging in leisure-time PA (ie, dichotomous outcome of some versus no leisure-time PA), transportation PA (ie, dichotomous outcome of some versus no transportation PA), and meeting national PA guidelines (ie, dichotomous outcome of meeting versus not meeting guidelines).ResultsPreliminary analyses showed that 10 participants reported excessively high PA levels and 1 participant had incomplete PA data; these women were excluded from analyses based on IPAQ scoring guidelines. The remaining 39 participants (mean age 40.5 years; mean length of US residency 4.6 years) reported a median of 4512 MET-minutes/week of total PA. The majority of PA was acquired through domestic activities (median 2160 MET-minutes/week), followed by leisure-time PA (median 396 MET-minutes/week), transportation PA (median 198 MET-minutes/week), and work PA (0 MET-minutes/week). Intensity-specific PA patterns showed a median of 594 MET-minutes/week of walking activity and 3500 MET-minutes/week of moderate-to-vigorous PA. Logistic regression models indicated that the neighborhood factors of walking environment, aesthetic quality, and safety were positively associated with engaging in leisure-time PA (odds ratios of 5.95, 95% CI 1.49-23.74; 2.45, 95% CI 1.01-5.93; and 3.30, 95% CI 1.26-8.67, respectively) and meeting national PA guidelines (odds ratios of 4.15, 95% CI 1.13-15.18; 6.43, 95% CI 1.45-28.39; and 2.53, 95% CI 1.00-6.36, respectively). The neighborhood factors of violence, social cohesion, and activities with neighbors were not significantly associated with PA outcomes.ConclusionsAlthough most participants met national PA guidelines (ie, ≥500 MET-minutes/week of moderate-to-vigorous PA), the majority of their PA was achieved through domestic activities, with limited leisure, transportation, and work PA. Given that leisure-time PA in particular plays a significant role in improving health outcomes, findings suggest that many Latina immigrants could benefit from a leisure-time PA intervention. Such interventions should consider neighborhood environmental influences, as these factors may serve as determinants of PA.

Project description:BACKGROUND:Streptococcus halichoeri infections have been reported in grey seals, a European badger, a Stellar sea lion and humans, but its presence in companion and fur animals is unknown. Since 2010, S. halichoeri-like bacteria (SHL) have been isolated from fur animals and dogs in Finland. Our aim was to retrospectively investigate laboratory records for SHL from canine and fur animal infections, characterize the isolates and compare their genetic relatedness in relation to three reference strains: CCUG 48324T, originating from a grey seal, and strains 67100 and 61265, originally isolated from humans. RESULTS:A total of 138 and 36 SHLs from canine and fur animal infections, respectively, were identified in the laboratory records. SHL was commonly associated with skin infections, but rarely as the only species. A set of 49 canine and 23 fur animal SHLs were further characterized. MALDI-TOF confirmed them as being S. halichoeri. The growth characteristics were consistent with the original findings, but isolates were catalase positive. In total, 17 distinct API 20 Strep patterns were recorded among all 75 isolates tested, of which pattern 5563100 was the most common (n?=?30). Antimicrobial resistance to erythromycin and clindamycin was common in canine isolates, but rare in fur animal isolates. Three clusters were observed by PFGE, and 16S rRNA sequencing revealed 98.1-100% similarities with the human strains and 98.1-99.5% with the seal strain. A phylogenetic tree of concatenated 16S rRNA and rpoB revealed closely related isolates with two clades. Fifteen canine isolates were identical to the human strains based on concatenated 16S rRNA and rpoB sequencing. CONCLUSIONS:Streptococcus halichoeri appears to be quite a common bacterial species in the skin of dogs and fur animals. The clinical significance of S. halichoeri is uncertain, as it was rarely isolated as a monoculture. No apparent temporal or spatial clustering was detected, but isolates from different sources were genetically very similar. Because many canine isolates were genetically similar to the human reference strains, transmission between dogs and humans may be possible. WGS sequencing of strains from different sources is needed to further investigate the epidemiology and virulence of S. halichoeri.

Project description:Chemosensory systems (CSS) are among the most complex organizations of proteins functioning cooperatively to regulate bacterial motility and other cellular activities. These systems have been studied extensively in bacteria, and usually, they are present as a single system. Eight CSS, the highest number in bacteria, have been reported in Myxococcus xanthus DK1622 and are involved in coordinating diverse functions. Here, we have explored and compared the CSS in all available genomes of order Myxococcales. Myxococcales members contain 97 to 476 two-component system (TCS) proteins, which assist the bacteria in surviving and adapting to varying environmental conditions. The number of myxobacterial CSS ranges between 1 and 12, with the largest number in family Cystobacteraceae and the smallest in Nannocystaceae CheA protein was used as a phylogenetic marker to infer evolutionary relatedness between different CSS, and six novel CSS ("extra CSS" [ECSS]) were thus identified in the myxobacteria besides the previously reported Che1 to Che8 systems from M. xanthus Che1 to Che8 systems are monophyletic to deltaproteobacteria, whereas the newly identified ECSS form separate clades with different bacterial classes. The comparative modular organization was concordant with the phylogeny. Four clusters lacking CheA proteins were also identified via CheB-based phylogenetic analysis and were categorized as accessory CSS (ACSS). In Archangium, an orphan CSS was identified, in which both CheA and CheB were absent. The novel, accessory, and orphan multimodular CSS identified here suggest the emergence of myxobacterial CSS and could assist in further characterizing their roles.IMPORTANCE This study is focused on chemosensory systems (CSS), which help the bacterium in directing its movement toward or away from chemical gradients. CSS are present as a single system in most of the bacteria except in some groups, including Myxococcus xanthus, which has 8 CSS, the highest number reported to date. This is the first comprehensive study carrying out a comparative analysis of the 22 available myxobacterial genomes, which suggests the evolutionary diversity of these systems. We are interested in understanding the distribution of CSS within all known myxobacteria and their probable evolution.

Dataset Information

Characteristics and living patterns of marine myxobacterial isolates.

Publications

Characteristics and living patterns of marine myxobacterial isolates.

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