Bacterial swarming reduces Proteus mirabilis and Vibrio parahaemolyticus cell stiffness and increases β-lactam susceptibility

Swarmer cells of the gram-negative pathogenic bacteria Proteus mirabilis and Vibrio parahaemolyticus become long (>10-100 microns) and multinucleate during their growth and motility on polymer surfaces. We demonstrate increasing cell length is accompanied by a large increase in flexibility. Using a microfluidic assay to measure single-cell mechanics, we identified large differences in swarmer cell stiffness of (bending rigidity of P. mirabilis, 9.6 x 10^(-22) N m^2; V. parahaemolyticus, 9.7 x 10^(-23) N m^2) compared to vegetative cells (1.4 x 10^(-20) N m^2 and 3.2 x 10^(-22) N m^2, respectively). The reduction in bending rigidity (~3-15 fold) was accompanied by a decrease in the average polysaccharide strand length of the peptidoglycan layer of the cell wall from 28-30 to 19-22 disaccharides. Atomic force microscopy revealed a reduction in P. mirabilis peptidoglycan thickness from 1.5 nm (vegetative) to 1.0 nm (swarmer) and electron cryotomography indicated changes in swarmer cell wall morphology. P. mirabilis and V. parahaemolyticus swarmer cells became increasingly sensitive to osmotic pressure and susceptible to cell wall-modifying antibiotics (compared to vegetative cells)--they were ~30% more likely to die after 3 h of treatment with minimum inhibitory concentrations of the beta-lactams cephalexin and penicillin G. Long, flexible swarmer cells enables these pathogenic bacteria to form multicellular structures and promotes community motility. The adaptive cost of swarming is offset by a fitness cost in which cells are more susceptible to physical and chemical changes in their environment, thereby suggesting the development of new chemotherapies for bacteria that leverage swarming for survival

Comparison of year-of-exam- and age-matched estimates of heritability in the Framingham Heart Study data

Several different approaches can be used to examine generational and temporal trends in family studies. The measurement of offspring and parents can be made over a short period of time with parents and offspring having quite different ages, or measurements can be made at the same ages but with decades between parent and offspring measures. A third approach, used in the Framingham Heart Study, has repeated examinations across a broad range of age and time, and provides a unique opportunity to compare these approaches. Parents and offspring were matched both on (year of exam) and on age. Heritability estimates for systolic blood pressure, body mass index, height, weight, cholesterol, and glucose were obtained by regressing offspring on midparent values with and without adjustment for age. Higher estimates of heritability were obtained for age-matched than for year-of-exam-matched data for all traits considered. For most traits, estimates of the heritability of the change over time (slope) of the trait were near zero. These results suggest that the optimal design to identify genetic effects in traits with large age-related effects may be to measure parents and offspring at similar ages and not to rely on age-adjustment or longitudinal measures to account for these temporal effects

Re-description and systematic re-appraisal of the genus Kokkocynips Pujade-Villar & Melika, (Hymenoptera: Cynipidae: Cynipini), including new combinations of Nearctic species and the description of a new species from Panama

The monophyly and taxonomic validity of some currently accepted genera of gall wasps in the Cynipini (Hymenoptera: Cynipidae) are being challenged by recent systematic studies. Here we used morphological and molecular data to re-describe and revise the taxonomic limits of the monotypic genus Kokkocynips Pujade-Villar & Melika, previously recorded only from Mexico. We describe a new species from Panama, Kokkocynips panamensis Medianero & Nieves-Aldrey, reared from galls on Quercus salicifolia Neé, and add new records from Mexico for the type species of the genus K. doctorrosae Pujade-Villar. Six Nearctic species, Dryocosmus rileyi (Ashmead, 1896), D. imbricariae (Ashmead, 1896), D. coxii (Basset, 1881), D. deciduus (Beutenmueller, 1913), Callirhytis difficilis (Ashmead, 1887) and C. attractans (Kinsey, 1922) are transferred to Kokkocynips. Species of Kokkocynips are associated only with red oaks (Quercus section Lobatae (Fagaceae)) and are distributed in the Nearctic and Neotropical regions, from Canada through Mexico and Panama. Taxonomic limits of Kokkocynips are discussed in light of the molecular phylogenetic relationships of the studied species. Diagnostic characters, gall description, distribution, and biological data of Kokkocynips species are given, including a key for the identification of the asexual generations of seven species.EM was funded by the Sistema Nacional de Investigación of the SENACYT in Panama, the University of Panama and research project SENACYT 52-2016-4-ITE15-05 and No. 266-20218. JLNA was supported by the research project MINECO/FEDER, UE CGL2015-66571-P. CTT was supported by USFS agreement 60-8042-8-002/8042-22000- 289-01-S.Peer reviewe

Kikuchi Fujimoto disease associated with cryptogenic organizing pneumonia: case report and literature review

<p>Abstract</p> <p>Background</p> <p>The association of Kikuchi Fujimoto disease (KFD) with cryptogenic organizing pneumonia (COP) is extremely rare. We report a case of simultaneous diagnosis of KFD and COP.</p> <p>Case Presentation</p> <p>A 33-year-old male presented with a 1-month cough illness and fever lasting for 5 days. The chest radiograph revealed double lower lobe infiltrate, which was unresponsive to antibiotics. A cervical lymph node was first found in the development of this disease. Bronchoscopy, bronchoalveolar lavage and lung biopsy established the diagnosis of COP, while a lymph node biopsy was consistent with KFD. The patient improved on steroids.</p> <p>Conclusions</p> <p>KFD and COP are possible part of a disease continuum, rather than separate entities.</p

Bacterial swarming reduces Proteus mirabilis and Vibrio parahaemolyticus cell stiffness and increases β-lactam susceptibility

Swarmer cells of the gram-negative pathogenic bacteria Proteus mirabilis and Vibrio parahaemolyticus become long (>10-100 microns) and multinucleate during their growth and motility on polymer surfaces. We demonstrate increasing cell length is accompanied by a large increase in flexibility. Using a microfluidic assay to measure single-cell mechanics, we identified large differences in swarmer cell stiffness of (bending rigidity of P. mirabilis, 9.6 x 10^(-22) N m^2; V. parahaemolyticus, 9.7 x 10^(-23) N m^2) compared to vegetative cells (1.4 x 10^(-20) N m^2 and 3.2 x 10^(-22) N m^2, respectively). The reduction in bending rigidity (~3-15 fold) was accompanied by a decrease in the average polysaccharide strand length of the peptidoglycan layer of the cell wall from 28-30 to 19-22 disaccharides. Atomic force microscopy revealed a reduction in P. mirabilis peptidoglycan thickness from 1.5 nm (vegetative) to 1.0 nm (swarmer) and electron cryotomography indicated changes in swarmer cell wall morphology. P. mirabilis and V. parahaemolyticus swarmer cells became increasingly sensitive to osmotic pressure and susceptible to cell wall-modifying antibiotics (compared to vegetative cells)--they were ~30% more likely to die after 3 h of treatment with minimum inhibitory concentrations of the beta-lactams cephalexin and penicillin G. Long, flexible swarmer cells enables these pathogenic bacteria to form multicellular structures and promotes community motility. The adaptive cost of swarming is offset by a fitness cost in which cells are more susceptible to physical and chemical changes in their environment, thereby suggesting the development of new chemotherapies for bacteria that leverage swarming for survival

New dryocosmus giraud species associated with cyclobalanopsis and non-quercus host plants from the eastern palaearctic (hymenoptera, cynipidae, cynipini)

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