Detecting bacteria in clinical samples without using time-consuming culture processes would allow rapid diagnoses. such a culture-free detection method requires the capture and analysis of bacteria from a body fluid, which are usually of complicated composition. Here we show that coating Ag-nanoparticle arrays with vancomycin (Van) can provide label-free analysis of bacteria via surface-enhanced Raman spectroscopy (sERs), leading to a ~1,000-fold increase in bacteria capture, without introducing significant spectral interference. Bacteria from human blood can be concentrated onto a microscopic Van-coated area while blood cells are excluded. Furthermore, a Van-coated substrate provides distinctly different sERs spectra of Van-susceptible and Van-resistant Enterococcus, indicating its potential use for drug-resistance tests. our results represent a critical step towards the creation of sERs-based multifunctional biochips for rapid culture-and label-free detection and drug-resistant testing of microorganisms in clinical samples.

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Background The Gesneriaceae genus Chiritopsis , confined almost exclusively to cave or cave-like microhabitats of limestone karsts of southern China, was described to distinguish it from Chirita by much smaller flowers and generally miniature plant sizes in the former genus. However, molecular phylogenetic analyses showed that Chiritopsis is polyphyletic and its species delimitation has been problematic. To understand how many times Chiritopsis-like species have evolved from within the recircumscribed Primulina and to further clarify their species identification, we sampled all but two recently described species of Chiritopsis-like Primulina and reconstructed their phylogenetic relationship based on DNA sequences of nuclear ITS and chloroplast trnL - F and trnH - psbA . Results With 182 accessions of 165 taxa of Primulina sampled, our analyses placed the 40 accessions of 25 taxa of Chiritopsis-like Primulina in 17 unrelated positions, indicating at least 17 independent origins of the traits associated with caves or cave-like microhabitats. Of the 17 clades containing Chiritopsis-like Primulina , Clade 1 is composed of P. bipinnatifida , P. cangwuensis , P. jianghuaensis , P. lingchuanensis , and P. zhoui , as well as additional samples that show variable and overlapping morphology in leaf shapes. Clade 10 includes P. cordifolia , P. huangii , and P. repanda , while Primulina repanda var. guilinensis is not placed within Clade 10. Primulina glandulosa var. yangshuoensis is not placed in the same clade of P. glandulosa . Conclusions Based on our data, P. cangwuensis , P. jianghuaensis , and P. lingchuanensis are proposed to synonymize under P. bipinnatifida , with P. zhoui treated as a variety of P. bipinnatifida . Primulina repanda var. guilinensis is transferred as P. subulata var. guilinensis comb. nov. and Primulina pseudoglandulosa nom. nov. is proposed for P. glandulosa var. yangshuoensis . One new species is named ...

BackgroundPrimulina cardaminifolia Yan Liu & W.B. Xu (Gesneriaceae), a distinct new species with imparipinnate leaves, is described and illustrated from a limestone valley in Guangxi Zhuangzu Autonomous Region, China. To assure its generic placement and phylogenetic affinity, phylogenetic analyses were performed using DNA sequences of nuclear ITS and chloroplast trnL-F intron spacer region. Additionally, somatic chromosome number was counted and pollen stainability was tested.ResultsPhylogenetic analyses support its placement in Primulina; however, two phylogenetically distinct ITS sequence types were detected, suggesting a probable hybrid origin. Its pollen stainability is 100% and its chromosome number, 2n = 36, is congruent with all known counts of diploid species of the genus.ConclusionAll available data support the recognition of the new species Primulina cardaminifolia and suggest that it could have derived from homoploid hybrid speciation. Color plates, line drawings and a distribution map are provided to aid in identification.Electronic supplementary materialThe online version of this article (doi:10.1186/1999-3110-54-19) contains supplementary material, which is available to authorized users.

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