54 research outputs found
Macromolecular Fingerprinting of Sulfolobus Species in Biofilm: A Transcriptomic and Proteomic Approach Combined with Spectroscopic Analysis
Microorganisms in nature often live in surfaceassociated
sessile communities, encased in a self-produced
matrix, referred to as biofilms. Biofilms have been well studied in
bacteria but in a limited way for archaea. We have recently characterized
biofilm formation in three closely related hyperthermophilic
crenarchaeotes: Sulfolobus acidocaldarius, S. solfataricus, and
S. tokodaii. These strains form different communities ranging
from simple carpet structures in S. solfataricus to high density
tower-like structures in S. acidocaldarius under static condition.
Here, we combine spectroscopic, proteomic, and transcriptomic
analyses to describe physiological and regulatory features
associated with biofilms. Spectroscopic analysis reveals that in
comparison to planktonic life-style, biofilm life-style has distinctive
influence on the physiology of each Sulfolobus spp.
Proteomic and transcriptomic data show that biofilm-forming
life-style is strain specific (eg ca. 15% of the S. acidocaldarius
genes were differently expressed, S. solfataricus and S. tokodaii
had ∼3.4 and ∼1%, respectively). The -omic data showed that regulated ORFs were widely distributed in basic cellular functions,
including surface modifications. Several regulated genes are common to biofilm-forming cells in all three species. One of the most
striking common response genes include putative Lrs14-like transcriptional regulators, indicating their possible roles as a key
regulatory factor in biofilm development
Sympathomimetic effects of chronic methamphetamine abuse on oral health: a cross-sectional study
Background: Methamphetamine, a highly addictive sympathomimetic stimulant, is currently widely abused worldwide and has been associated with devastating effects on oral health, resulting in the term "meth mouth". However, "meth mouth" pathology is primarily based on case reports with a lack of systematic clinical evaluation. Therefore, we have conducted a systematic study to investigate (1) the pharmacological impact of methamphetamine on oral health with regard to saliva function, including the parameters saliva flow rate and total saliva production (ml/5 min) and the buffering capacity of saliva;(2) the contribution of the symptoms of bruxism and muscle trismus to potential oral health damage. Methods: We assessed the data of 100 chronic methamphetamine abusers and 100 matched-pair comparison participants. Primarily, we conducted an anamnesis with all methamphetamine abusers with regard to saliva dysfunctions, jaw clenching and pain in the temporomandibular joint. Subsequently, in the first part of the clinical enquiry, we tested the saliva flow rate and the total saliva production (ml/5 min) by using the sialometry method and the buffer capacity of saliva by determining the pH-value. In the second part of the clinical enquiry, we evaluated bruxism symptoms with respect to generalized tooth attrition, dentine exposure and visible enamel cracks and examined a potential muscle trismus by measuring the maximal opening of the mouth. Results: The majority of methamphetamine abusers reported a dry mouth (72 %) and jaw clenching (68 %). Almost half of all methamphetamine abusers experienced pain in the temporomandibular joint (47 %). With regard to the clinical findings, methamphetamine abusers showed significantly lower total saliva production (ml/5 min) (p 0.05). Conclusions: The sympathomimetic effects of chronic methamphetamine abuse may lead to dry mouth and extensive bruxism and therefore can increase the risk for caries decay, periodontal lesions and tooth wear. Furthermore, a significant decline of saliva buffer capacity in methamphetamine abusers may trigger the risk for dental erosions. Methamphetamine abusers and practitioners should be aware of these symptoms
Chirality of Matter Shows Up via Spin Excitations
Right- and left-handed circularly polarized light interact differently with
electronic charges in chiral materials. This asymmetry generates the natural
circular dichroism and gyrotropy, also known as the optical activity. Here we
demonstrate that optical activity is not a privilege of the electronic charge
excitations but it can also emerge for the spin excitations in magnetic matter.
The square-lattice antiferromagnet BaCoGeO offers an ideal arena to
test this idea, since it can be transformed to a chiral form by application of
external magnetic fields. As a direct proof of the field-induced chiral state,
we observed large optical activity when the light is in resonance with spin
excitations at sub-terahertz frequencies. In addition, we found that the
magnetochiral effect, the absorption difference for the light beams propagating
parallel and anti-parallel to the applied magnetic field, has an exceptionally
large amplitude close to 100%. All these features are ascribed to the
magnetoelectric nature of spin excitations as they interact both with the
electric and magnetic components of light
Appendage-mediated surface adherence in Sulfolobus solfataricus
Attachment of microorganisms to surfaces is a prerequisite for colonization and biofilm formation. The hyperthermophilic crenarchaeote Sulfolobus solfataricus was able to attach to a variety of surfaces such as glass, mica, pyrite and carboncoated gold grids. Deletion mutant analysis showed that for initial attachment the presence of flagella and pili is essential. Attached cells produced extracellular polysaccharides containing mannose, galactose and N-acetylglucosamine. Genes possibly involved in the production of the extracellular polysaccharides were identified
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