Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 2018  (9)
Type of Medium
Language
Year
  • 2018  (9)
  • 1
    Language: English
    In: Journal of bacteriology, 01 February 2018, Vol.200(3)
    Description: Attachment is essential for microorganisms to establish interactions with both biotic and abiotic surfaces. Stable attachment of to surfaces requires an adhesive polysaccharide holdfast, but the exact composition of the holdfast is unknown. The holdfast is anchored to the cell envelope by outer membrane proteins HfaA, HfaB, and HfaD. oldast nchor gene mutations result in holdfast shedding and reduced cell adherence. Translocation of HfaA and HfaD to the cell surface requires HfaB. The Wzx homolog HfsF is predicted to be a bacterial polysaccharide flippase. An deletion significantly reduced the amount of holdfast produced per cell and slightly reduced adherence. A Δ Δ double mutant was completely deficient in adherence. A suppressor screen that restored adhesion in the Δ Δ mutant identified mutations in three genes: , , and Both WbqV and RfbB belong to a family of nucleoside-diphosphate epimerases, and RmlA has similarity to nucleotidyltransferases. The loss of or in the Δ Δ mutant reduced holdfast shedding but did not restore holdfast synthesis to parental levels. Loss of or did not restore adherence to a Δ mutant but did restore adherence and holdfast anchoring to a Δ mutant, confirming that suppression occurs through restoration of holdfast anchoring. The adherence and holdfast anchoring of a Δ mutant could be restored by or mutation, but such mutations could not suppress these phenotypes in the Δ mutant. We hypothesize that HfaB plays an additional role in holdfast anchoring or helps to translocate an unknown factor that is important for holdfast anchoring. Biofilm formation results in increased resistance to both environmental stresses and antibiotics. requires an adhesive holdfast for permanent attachment and biofilm formation, but the exact mechanism of polysaccharide anchoring to the cell and the holdfast composition are unknown. Here we identify novel polysaccharide genes that affect holdfast anchoring to the cell. We identify a new role for the holdfast anchor protein HfaB. This work increases our specific knowledge of the polysaccharide adhesin involved in attachment and the general knowledge regarding production and anchoring of polysaccharide adhesins by bacteria. This work also explores the interactions between different polysaccharide biosynthesis and secretion systems in bacteria.
    Keywords: Caulobacter ; Adherence ; Holdfast ; Polysaccharides ; Mutation ; Adhesins, Bacterial -- Genetics ; Bacterial Proteins -- Genetics ; Caulobacter Crescentus -- Genetics ; Nucleotides -- Genetics ; Polysaccharides, Bacterial -- Genetics ; Sugars -- Metabolism
    ISSN: 00219193
    E-ISSN: 1098-5530
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Language: English
    In: Gastroenterology, May 2018, Vol.154(6), pp.S-857-S-857
    Keywords: Medicine
    ISSN: 0016-5085
    E-ISSN: 1528-0012
    Source: ScienceDirect Journals (Elsevier)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Infection and immunity, July 2018, Vol.86(7)
    Description: Some members of the genus , including the human pathogen , infect multiple tissues, including the genital and gastrointestinal (GI) tracts. However, it is unknown if bacterial targeting to these sites is mediated by multifunctional or distinct chlamydial factors. We previously showed that disruption of individual large clostridial toxin homologs encoded within the plasticity zone were not critical for murine genital tract infection. Here, we assessed whether cytotoxin genes contribute to GI tropism. Infectivity and shedding of wild-type (WT) and three mutants containing nonsense mutations in different cytotoxin genes, , , and , were compared in mouse genital and GI infection models. One mutant, which had a nonsense mutation in , was highly attenuated for GI infection and had a GI 50% infectious dose (ID) that was 1,000 times greater than that of the WT. GI inoculation with this mutant failed to elicit anti-chlamydial antibodies or to protect against subsequent genital tract infection. Genome sequencing of the mutant revealed additional chromosomal mutations, and phenotyping of additional mutants suggested that the GI attenuation might be linked to a nonsense mutation in The molecular mechanism underlying this dramatic difference in tissue-tropic virulence is not fully understood. However, isolation of these mutants demonstrates that distinct chlamydial chromosomal factors mediate chlamydial tissue tropism and provides a basis for vaccine initiatives to isolate chlamydia strains that are attenuated for genital infection but retain the ability to colonize the GI tract and elicit protective immune responses.
    Keywords: Chlamydia ; Gastrointestinal Infection ; Genital Tract Immunity ; Intracellular Bacteria ; Intracellular Pathogen ; Sexually Transmitted Diseases ; Tropism ; Chlamydia Infections -- Etiology ; Chlamydia Muridarum -- Pathogenicity ; Chromosomes -- Physiology ; Gastrointestinal Diseases -- Etiology ; Reproductive Tract Infections -- Etiology
    ISSN: 00199567
    E-ISSN: 1098-5522
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Language: English
    In: Body image, 23 December 2018, Vol.28, pp.66-75
    Description: The 10-item Body Appreciation Scale-2 (BAS-2) is a widely-used measure of a facet of positive body image. Here, we examined the psychometric properties of a Bahasa Malaysia (Malay) translation of the BAS-2 in a community sample of Malaysian Malay and Chinese adults (N = 781). Participants completed the Malay BAS-2 alongside demographic items and measures of subjective happiness, life satisfaction, actual-ideal weight discrepancy (women only), drive for muscularity (men only), and internalisation of appearance ideals. Exploratory factor analyses with a Malay subsample indicated that BAS-2 scores reduced to a single dimension with all 10 items in women and men, although the factor structure was similar but not identical across sex. Confirmatory factor analysis indicated that the one-dimensional factor structure had adequate fit following modifications. BAS-2 scores were partially scalar invariant across sex (with no significant sex differences) and ethnicity (Malay participants had significantly higher body appreciation than Chinese participants), as well as had adequate internal consistency. Evidence of construct and incremental validity was also provided through associations with additional measures and the prediction of subjective happiness over-and-above other variables, respectively. The availability of the Malay BAS-2 should help advance research on the body appreciation construct in Malay-speaking populations.
    Keywords: Body Appreciation ; Malaysia ; Positive Body Image ; Psychometrics ; Test Adaptation
    ISSN: 17401445
    E-ISSN: 1873-6807
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Language: English
    In: Body image, 29 December 2018, Vol.28, pp.81-92
    Description: The 34-item Multidimensional Body-Self Relations Questionnaire-Appearance Scales (MBSRQ-AS) is a widely-used measure of multidimensional body image. Here, we examined the psychometric properties of a Bahasa Malaysia (Malay) translation of the MBSRQ-AS. A sample of 629 Malaysian Malays (women n = 315) completed the MBSRQ-AS, as well as measures of body appreciation, psychological well-being, perceptions of appearance ideals, and internalisation of appearance ideals. Exploratory factor analysis indicated that the MBSRQ-AS items reduced to four dimensions, although one factor had less-than-adequate internal consistency. Omitting this factor resulted in a 23-item 3-factor solution, which we tested for fit using confirmatory factor analysis (CFA) alongside the parent 5-factor model. CFA indicated that both models had good fit on some indices, but less-than-ideal fit on other indices, with the 3-factor model showing comparatively better fit. Multi-group CFA indicated that it was not possible to achieve scalar invariance across sex, but internal consistency coefficients were adequate. Evidence of construct validity, as assessed through correlations between MBSRQ-AS scores and additional measures, was mixed. We discuss reasons that complicate interpretation of the dimensionality of MBSRQ-AS scores in this and previous studies, and call for further research on this issue.
    Keywords: Mbsrq ; Mbsrq–As ; Malaysia ; Multidimensional Body Image ; Test Adaptation
    ISSN: 17401445
    E-ISSN: 1873-6807
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Language: English
    In: Scientific Reports, 01 November 2018, Vol.8(1), pp.1-17
    Description: Abstract We compared the gut microbial populations in 100 women, from rural Ghana and urban US [50% lean (BMI 〈 25 kg/m2) and 50% obese (BMI ≥ 30 kg/m2)] to examine the ecological co-occurrence network topology of the gut microbiota as well as the relationship of short chain fatty acids (SCFAs) with obesity. Ghanaians consumed significantly more dietary fiber, had greater microbial alpha-diversity, different beta-diversity, and had a greater concentration of total fecal SCFAs (p-value 〈 0.002). Lean Ghanaians had significantly greater network density, connectivity and stability than either obese Ghanaians, or lean and obese US participants (false discovery rate (FDR) corrected p-value ≤ 0.01). Bacteroides uniformis was significantly more abundant in lean women, irrespective of country (FDR corrected p 〈 0.001), while lean Ghanaians had a significantly greater proportion of Ruminococcus callidus, Prevotella copri, and Escherichia coli, and smaller proportions of Lachnospiraceae, Bacteroides and Parabacteroides. Lean Ghanaians had a significantly greater abundance of predicted microbial genes that catalyzed the production of butyric acid via the fermentation of pyruvate or branched amino-acids, while obese Ghanaians and US women (irrespective of BMI) had a significantly greater abundance of predicted microbial genes that encoded for enzymes associated with the fermentation of amino-acids such as alanine, aspartate, lysine and glutamate. Similar to lean Ghanaian women, mice humanized with stool from the lean Ghanaian participant had a significantly lower abundance of family Lachnospiraceae and genus Bacteroides and Parabacteroides, and were resistant to obesity following 6-weeks of high fat feeding (p-value 〈 0.01). Obesity-resistant mice also showed increased intestinal transcriptional expression of the free fatty acid (Ffa) receptor Ffa2, in spite of similar fecal SCFAs concentrations. We demonstrate that the association between obesity resistance and increased predicted ecological connectivity and stability of the lean Ghanaian microbiota, as well as increased local SCFA receptor level, provides evidence of the importance of robust gut ecologic network in obesity.
    Keywords: Biology
    E-ISSN: 2045-2322
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Language: English
    In: Biotechnology and bioengineering, 29 December 2018
    Description: Human pluripotent stem cell-derived endothelial cells (hPSC-ECs) present an attractive alternative to primary EC sources for vascular grafting. However, there is a need to mature them towards either an arterial or venous subtype. A vital environmental factor involved in the arteriovenous specification of ECs during early embryonic development is fluid shear stress; therefore, there have been attempts to employ adult arterial shear stress conditions to mature hPSC-ECs. However, hPSC-ECs are naïve to fluid shear stress, and their shear responses are still not well understood. Here, we used a multiplex microfluidic platform to systematically investigate the dose-time shear responses on hPSC-EC morphology and arterial-venous phenotypes over a range of magnitudes coincidental with physiological levels of embryonic and adult vasculatures. The device comprised of six parallel cell culture chambers that were individually linked to flow-setting resistance channels, allowing us to simultaneously apply shear stress ranging from 0.4 to 15 dyne/cm . We found that hPSC-ECs required up to 40 hr of shear exposure to elicit a stable phenotypic change. Cell alignment was visible at shear stress 〈1 dyne/cm , which was independent of shear stress magnitude and duration of exposure. We discovered that the arterial markers NOTCH1 and EphrinB2 exhibited a dose-dependent increase in a similar manner beyond a threshold level of 3.8 dyne/cm , whereas the venous markers COUP-TFII and EphB4 expression remained relatively constant across different magnitudes. These findings indicated that hPSC-ECs were sensitive to relatively low magnitudes of shear stress, and a critical level of ~4 dyne/cm was sufficient to preferentially enhance their maturation into an arterial phenotype for future vascular tissue engineering applications.
    Keywords: Arterial-Venous Specification ; Biophysical Cues ; Functional Maturation ; Human Pluripotent Stem Cell-Derived Endothelial Cells ; Microfluidics ; Shear Stress
    ISSN: 00063592
    E-ISSN: 1097-0290
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Language: English
    In: The Journal of Allergy and Clinical Immunology: In Practice, March 2018, Vol.6(2), pp.466-475.e1
    Description: There is mounting evidence that early introduction of allergenic food decreases the risk of food allergy development, especially in high-risk infants with eczema. However, there is a lack of data to suggest whether this association holds true in Asian populations. To investigate the relationship between the timing of introduction of allergenic foods and food allergy outcomes in infants in the Growing Up in Singapore Towards healthy Outcomes (GUSTO) study. The GUSTO cohort recruited 1152 mothers of Chinese, Malay, and Indian ethnicity who had singleton, naturally conceived pregnancies and followed their offspring prospectively. Information on demographic characteristics, child health, infant feeding practices, and a convincing history of IgE-mediated food allergy was obtained from interviewer-administered questionnaires at multiple time points. Corroborative skin prick tests to food allergens were performed at 18 and 36 months. Most of the infants were introduced to egg (49.6%), peanut (88.7%), and shellfish (90.2%) after age 10 months. Food allergy prevalence was, however, very low between age 12 and 48 months: egg, 0.35% to 1.8%; peanut allergy, 0.1% to 0.3%; and shellfish, 0.2% to 0.9%. There were no significant associations between the timing of introduction of allergenic foods and the development of food allergy, adjusted for confounders including breast-feeding and eczema. Food allergy rates in Singapore are low despite delayed introduction of allergenic foods. Early introduction of allergenic foods may thus not be necessary in populations in which overall food allergy prevalence is low, and thus infant feeding recommendations should be carefully tailored to individual populations.
    Keywords: Food Allergy ; Allergy Prevention ; Solids Introduction ; Allergenic Food Introduction ; Complementary Feeding ; Egg ; Milk ; Peanut ; Medicine
    ISSN: 2213-2198
    E-ISSN: 2213-2201
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    In: Open Forum Infectious Diseases, 2018, Vol. 5(7)
    Description: Abstract Background This study examined the cellular immunity of 0, 1, 2, and 3 doses of Gardasil vaccine (4vHPV) in girls after 6 years and their responses to a subsequent dose of Cervarix vaccine (2vHPV). Methods A subset of girls (n = 59) who previously received 0, 1, 2, or 3 doses of 4vHPV 6 years earlier were randomly selected from a cohort study of Fijian girls (age 15–19 years). Blood was collected before and 28 days after a dose of 2vHPV. The HPV16- and HPV18-specific cellular immune response was determined by IFNγ-ELISPOT and by measurement of cytokines in peripheral blood mononuclear cell supernatants. Results Six years after 4vHPV vaccination, HPV18-specific responses were significantly lower in the 1- (1D) or 2-dose (2D) recipients compared with 3-dose recipients (2D: IFNγ-ELISPOT: P = .008; cytokines, IFNγ: P = .002; IL-2: P = .022; TNFα: P = .016; IL-10: P = .018; 1D: IL-2: P = .031; IL-10: P = .014). These differences were no longer significant post-2vHPV. No significant differences in HPV16 responses (except IL-2, P 〈 .05) were observed between the 2- or 1-dose recipients and 3-dose recipients. Conclusions These data suggest that cellular immunity following reduced-dose schedules was detectable after 6 years, although the responses were variable between HPV types and dosage groups. The clinical significance of this is unknown. Further studies on the impact of reduced dose schedules are needed, particularly in high–disease burden settings.
    Keywords: Adolescents ; Cellular Immune Responses ; Human Papillomavirus Vaccine ; Immune Memory ; Reduced Doses
    E-ISSN: 2328-8957
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages