ABSTRACT
The development of facile, reliable, and accurate assays for pathogenic bacteria is critical to environmental pollution surveillance, traceability analysis, prevention, and control. Here, we proposed a rolling circle amplification (RCA) strategy-driven visual photothermal smartphone-based biosensor for achieving highly sensitive monitoring of Escherichia coli (E. coli) in environmental media. In this design, E. coli could specifically bind with its recognition aptamer for initiating the RCA process on a magnetic bead (MB). Owing to the cleaving of UV irradiation toward photoresponsive DNA on MB, the RCA products were released to further hybridize with near-infrared excited CuxS-modified DNA probes. As a result, the photothermal signal was enhanced by RCA, while the background was decreased by UV irradiation and magnetic separation. The correspondingly generated photothermal signals were unambiguously recorded on a smartphone, allowing for an E. coli assay with a low detection limit of 1.8 CFU/mL among the broad linear range from 5.0 to 5.0 × 105 CFU/mL. Significantly, this proposed biosensor has been successfully applied to monitor the fouling levels of E. coli in spring water samples with acceptable results. This study holds great prospects by integrating a RCA-driven photothermal amplification strategy into a smartphone to develop accurate, reliable, and efficient analytical platforms against pathogenic bacteria pollutions for safeguarding environmental health.
Subject(s)
Biosensing Techniques , Escherichia coli Infections , Humans , Escherichia coli/genetics , Escherichia coli/metabolism , Nucleic Acid Amplification Techniques/methods , Biosensing Techniques/methods , DNA/genetics , Magnetic Phenomena , Limit of DetectionABSTRACT
BACKGROUND AND AIMS: In angiosperms, many species disperse their seeds autonomously by rapid movement of the pericarp. The fruits of these species often have long rod- or long plate-shaped pericarps, which are suitable for ejecting seeds during fruit dehiscence by bending or coiling. However, here we show that fruit with a completely different shape can also rely on pericarp movement to disperse seeds explosively, as in Orixa japonica. METHODS: Fruit morphology was observed by hard tissue sectioning, scanning electron microscopy and micro-computed tomography, and the seed dispersal process was analysed using a high-speed camera. Comparisons were made of the geometric characteristics of pericarps before and after fruit dehiscence, and the mechanical process of pericarp movement was simulated with the aid of the finite element model. KEY RESULTS: During fruit dehydration, the water drop-shaped endocarp of O. japonica with sandwich structure produced two-way bending deformation and cracking, and its width increased more than three-fold before opening. Meanwhile the same shaped exocarp with uniform structure could only produce small passive deformation under relatively large external forces. The endocarp forced the exocarp to open by hygroscopic movement before seed launching, and the exocarp provided the acceleration for seed launching through a reaction force. CONCLUSIONS: Two layers of water drop-shaped pericarp in O. japonica form a structure similar to a slingshot, which launches the seed at high speed during fruit dehiscence. The results suggest that plants with explosive seed dispersal appear to have a wide variety of fruit morphology, and through a combination of different external shapes and internal structures, they are able to move rapidly using many sophisticated mechanisms.
Subject(s)
Explosive Agents , Rutaceae , Seed Dispersal , Fruit , Seeds , Water , X-Ray MicrotomographyABSTRACT
OBJECTIVES: To study the consistency between nasopharyngeal aspirates (NPA) and bronchoalveolar lavage fluid (BALF) in pathogen detection in children with pneumonia. METHODS: A retrospective analysis was performed on the data of pathogens detected in 533 children with pneumonia from February 2017 to March 2020. The paired McNemar's test was used to compare the difference in pathogen detection between NPA and BALF groups. The Kappa coefficient was used to analyze the consistency in pathogen detection between the two groups. RESULTS: NPA had a sensitivity of 28%, a specificity of 74%, a positive predictive value of 14%, and a negative predictive value of 91% in detecting bacteria, and a Kappa coefficient of 0.013 suggested poor consistency between NPA and BALF. NPA had a sensitivity of 52%, a specificity of 81%, a positive predictive value of 24%, and a negative predictive value of 94% in detecting viruses, and a Kappa coefficient of 0.213 suggested poor consistency between NPA and BALF. NPA had a sensitivity of 78%, a specificity of 71%, a positive predictive value of 49%, and a negative predictive value of 90% in detecting Mycoplasma pneumoniae, and a Kappa coefficient of 0.407 suggested moderate consistency between NPA and BALF. CONCLUSIONS: There is poor consistency between NPA and BALF in the detection of bacteria and viruses, and clinicians should be cautious in diagnosing lower respiratory tract infection based on bacteria or viruses detected in NPA. There is moderate consistency between NPA and BALF in the detection of Mycoplasma pneumoniae, suggesting that it may be reliable to diagnose lower respiratory tract infection based on Mycoplasma pneumoniae detected in NPA, while comprehensive judgment in combination with clinical conditions is needed.
Subject(s)
Pneumonia, Mycoplasma , Pneumonia , Respiratory Tract Infections , Bronchoalveolar Lavage Fluid , Child , Humans , Mycoplasma pneumoniae , Retrospective StudiesABSTRACT
The freshwater macrophyte, Ottelia alismoides, is a bicarbonate user performing C4 photosynthesis in the light, and crassulacean acid metabolism (CAM) when acclimated to low CO2. The regulation of the three mechanisms by CO2 concentration was studied in juvenile and mature leaves. For mature leaves, the ratios of phosphoenolpyruvate carboxylase (PEPC) to ribulose-bisphosphate carboxylase/oxygenase (Rubisco) are in the range of that of C4 plants regardless of CO2 concentration (1.5-2.5 at low CO2, 1.8-3.4 at high CO2). In contrast, results for juvenile leaves suggest that C4 is facultative and only present under low CO2. pH-drift experiments showed that both juvenile and mature leaves can use bicarbonate irrespective of CO2 concentration, but mature leaves have a significantly greater carbon-extracting ability than juvenile leaves at low CO2. At high CO2, neither juvenile nor mature leaves perform CAM as indicated by lack of diurnal acid fluctuation. However, CAM was present at low CO2, though the fluctuation of titratable acidity in juvenile leaves (15-17 µequiv g-1 FW) was slightly but significantly lower than in mature leaves (19-25 µequiv g-1 FW), implying that the capacity to perform CAM increases as leaves mature. The increased CAM activity is associated with elevated PEPC activity and large diel changes in starch content. These results show that in O. alismoides, carbon-dioxide concentrating mechanisms are more effective in mature compared to juvenile leaves, and C4 is facultative in juvenile leaves but constitutive in mature leaves.
Subject(s)
Acclimatization/physiology , Carbon Dioxide , Hydrocharitaceae/physiology , Plant Leaves/drug effects , Plant Leaves/growth & development , Hydrocharitaceae/enzymology , Hydrogen-Ion Concentration , Plant Leaves/enzymology , Plant Transpiration , Starch/metabolismABSTRACT
OBJECTIVE: To detect concentrations of serum gonadal hormones (testosterone, estradiol and progesterone) in musk-secreting period and estrus of Moschus berezovskii, and to study the association of serum gonadal hormones concentrations and musk-secreting. METHODS: The concentrations of serum gonadal hormones were detected with magnetic particle separation ELISA. RESULTS: During musk-secreting period, concentration changes of three serum gonadal hormones showed clear regularity, three crests occurred synchronously. Before musk-secreting period, testosterone, estradiol and progesterone concentrations were at its lower level, in prime musk-secreting period, they increased rapidly to respective highest peak; at later musk-secreting period, they quickly dropped to close to its previous levels before musk-secreting period. During estrus, serum testosterone concentration increased to lower peaks than that at later musk-secreting period. Estradiol remained at a low level and progesterone level was closed to zero. Serum testosterone concentrations in prime musk-secreting period were 114.4 ~ 190.5 times of estrus. During musk-secreting period, there were significant positive correlation among three serum gonadal hormone levels, a positive correlation between musk yield and serum testosterone levels, and negative correlation of musk yield with serum estradiol and progesterone levels as well as musk deer ages. CONCLUSION: Serum testosterone concentrations in prime musk-secreting period increase to the highest levels,which can provide reference in musk secretion induced by artificial means.
Subject(s)
Estrus/blood , Fatty Acids, Monounsaturated , Gonadal Hormones/blood , Ruminants/blood , Animals , Estradiol/blood , Female , Progesterone/blood , Testosterone/bloodABSTRACT
Forest musk deer (Moschus berezovskii) are currently a threatened species under conservation, and the development of captive populations is restricted by health problems. To evaluate the application potential of interferon (IFN)-ω in the prevention and control of forest musk deer disease, 5 forest musk deer IFN-ω (fmdIFNω) gene sequences were successfully obtained by homologous cloning method for the first time. FmdIFNω5 was selected and recombinant fmdIFNω protein (rIFNω) was successfully expressed by pGEX-6P-1 plasmid and E. coli expression system. The obtained protein was used to stimulate forest musk deer lung fibroblasts cells FMD-C1 to determine its regulatory effect on interferon-stimulated genes (ISGs). In addition, an indirect ELISA method based on anti-rIFNω serum was established to detect endogenous IFN-ω levels in 8 forest musk deer. The results showed that there were 18 amino acid differences among the 5 fmdIFNω subtypes, all of which had the basic structure to exert the activity of type I IFN and were close to Cervus elaphus IFN-ω in the phylogenetic tree. The protein expressed was 48 kDa, and the transcription levels of all ISGs were increased in FMD-C1 cells stimulated by rIFNω, and the amount of transcription accumulation was time-dependent. Meanwhile, Anti-rIFNω serum of mice could react with both rIFNω and forest musk deer serum, and the OD450nm value of forest musk deer serum with the most obvious symptoms was the highest, suggesting that the level of natural IFN-ω in different forest musk deer could be monitored by the rIFNω-based ELISA method. These results indicate that fmdIFNω has the potential as an antiviral drug and an early indication of innate immunity, which is of great significance for the prevention and control of forest musk deer diseases.
Subject(s)
Deer , Interferon Type I , Animals , Mice , Escherichia coli/genetics , Phylogeny , Cloning, Molecular , Ruminants , Interferon Type I/genetics , ForestsABSTRACT
In this study, we fed the larval of Bombyx mori silkworms with nanodroplets of liquid metal (LM) coated with microgels of marine polysaccharides to obtain stretchable silk. Alginate-coated liquid metal nanodroplets (LM@NaAlg) were prepared with significant chemical stability and biocompatibility. This study demonstrates how the fed LM@NaAlg acts on the as-spun silk fiber. We also conducted a series of characterizations and steered molecular dynamics simulations, which showed that the LM@NaAlg additions impede the conformation transition of silk fibroins from the random coil and α-helix to the ß-sheet by the formation of hydrogen bonds between LM@NaAlg and the silk fibroins, thus enhancing the elongation at the breakpoints in addition to the tensile properties. The intrinsically highly stretchable silk showed outstanding mechanical properties compared with regular silk due to its 814 MPa breaking strength and a breaking elongation of up to 70%-the highest reported performance so far. We expect that the proposed method can expand the fabrication of multi-functional silks.
ABSTRACT
Inspired by information processing and logic operations of life, many artificial biochemical systems have been designed for applications in molecular information processing. However, encoding the binary synergism between matter, energy, and information in a superwetting system remains challenging. Herein, a superwetting paradigm was proposed for multifunctional applications including molecular visual sensing and data security on a superhydrophobic surface. A Triton X-100-encapsulated gelatin (TeG) hydrogel was prepared and selectively decomposed by trypsin, releasing the surfactant to decrease the surface tension of a droplet. Integrating the droplet with the superhydrophobic surface, the superwetting behavior was utilized for visual detection and information encoding. Interestingly, the proposed TeG hydrogel can function as an artificial gelneuron for molecular-level logic computing, where the combination of matters (superhydrophobic surface, trypsin, and leupeptin) acts as inputs to interact with energy (liquid surface tension and solid surface energy) and information (binary character), resulting in superwettability transitions (droplet surface tension, contact angle, rolling angle, and bounce) as outputs. Impressively, the TeG gelneuron can be further developed as molecular-level double cryptographic steganography to encode, encrypt, and hide specific information (including the maze escape route and content of the classical literature) due to its programmability, stimuli responsive ability, and droplet concealment. This study will encourage the development of advanced molecular paradigms and their applications, such as superwetting visual sensing, molecular computing, interaction, and data security.
ABSTRACT
OBJECTIVE: To determine the clinical characteristics and prognosis of primary tracheobronchial tumors (PTTs) in children, and to explore the most common tumor identification methods. METHODS: The medical records of children with PTTs who were hospitalized at the Children's Hospital of Chongqing Medical University from January 1995 to January 2020 were reviewed retrospectively. The clinical features, imaging, treatments, and outcomes of these patients were statistically analyzed. Machine learning techniques such as Gaussian naïve Bayes, support vector machine (SVM) and decision tree models were used to identify mucoepidermoid carcinoma (ME). RESULTS: A total of 16 children were hospitalized with PTTs during the study period. This included 5 (31.3%) children with ME, 3 (18.8%) children with inflammatory myofibroblastic tumors (IMT), 2 children (12.5%) with sarcomas, 2 (12.5%) children with papillomatosis and 1 child (6.3%) each with carcinoid carcinoma, adenoid cystic carcinoma (ACC), hemangioma, and schwannoma, respectively. ME was the most common tumor type and amongst the 3 ME recognition methods, the SVM model showed the best performance. The main clinical symptoms of PPTs were cough (81.3%), breathlessness (50%), wheezing (43.8%), progressive dyspnea (37.5%), hemoptysis (37.5%), and fever (25%). Of the 16 patients, 7 were treated with surgery, 8 underwent bronchoscopic tumor resection, and 1 child died. Of the 11 other children, 3 experienced recurrence, and the last 8 remained disease-free. No deaths were observed during the follow-up period. CONCLUSION: PTT are very rare in children and the highest percentage of cases is due to ME. The SVM model was highly accurate in identifying ME. Chest CT and bronchoscopy can effectively diagnose PTTs. Surgery and bronchoscopic intervention can both achieve good clinical results and the prognosis of the 11 children that were followed up was good.
Subject(s)
Bronchial Neoplasms , Carcinoma, Mucoepidermoid , Bayes Theorem , Bronchial Neoplasms/diagnostic imaging , Bronchial Neoplasms/surgery , Bronchoscopy/methods , Carcinoma, Mucoepidermoid/diagnostic imaging , Carcinoma, Mucoepidermoid/surgery , Child , Humans , Retrospective StudiesABSTRACT
Floral nectaries are closely associated with biotic pollination, and the nectar produced by corolla nectaries is generally enclosed in floral structures. Although some Swertia spp. (Gentianaceae), including S. bimaculata, evolved a peculiar form of corolla nectaries (known as "gland patches") arranged in a conspicuous ring on the rotate corolla and that completely expose their nectar, little is known about the pollination of these plants. Two hypotheses were made concerning the possible effects of gland patches: visual attraction and visitor manipulation. The floral traits, mating system, and insect pollination of S. bimaculata were examined, and the pollination effects of gland patches were evaluated. A comparative study was made using Swertia kouitchensis, a species with fimbriate nectaries. Swertia bimaculata flowers were protandrous, with obvious stamen movement leading to herkogamy in the female phase and to a significant reduction in nectary-anther distance. The species is strongly entomophilous and facultatively xenogamous. The daily reward provided per flower decreased significantly after the male phase. The most effective pollinators were large dipterans, and the visiting proportion of Diptera was significantly higher in S. bimaculata than in S. kouitchensis. Most visitors performed "circling behavior" in S. bimaculata flowers. Removing or blocking the nectaries caused no reduction in visiting frequency but a significant reduction in visit duration, interrupting the circling behavior. The circling behavior was encouraged by nectar abundance and promoted pollen dispersal. Visitor species with small body size had little chance to contact the anthers or stigma, revealing a filtration effect exerted by the floral design. These results rejected the "visual attraction" hypothesis and supported the "visitor manipulation" hypothesis. The nectary whorl within a flower acted like a ring-shaped track that urged nectar foragers to circle on the corolla, making pollination in S. bimaculata flowers more orderly and selective than that in classically generalist flowers.
ABSTRACT
The capability of neurons to discriminate between intensity of external stimulus is measured by its dynamic range. A larger dynamic range indicates a greater probability of neuronal survival. In this study, the potential roles of adaptation mechanisms (ion currents) in modulating neuronal dynamic range were numerically investigated. Based on the adaptive exponential integrate-and-fire model, which includes two different adaptation mechanisms, i.e. subthreshold and suprathreshold (spike-triggered) adaptation, our results reveal that the two adaptation mechanisms exhibit rather different roles in regulating neuronal dynamic range. Specifically, subthreshold adaptation acts as a negative factor that observably decreases the neuronal dynamic range, while suprathreshold adaptation has little influence on the neuronal dynamic range. Moreover, when stochastic noise was introduced into the adaptation mechanisms, the dynamic range was apparently enhanced, regardless of what state the neuron was in, e.g. adaptive or non-adaptive. Our model results suggested that the neuronal dynamic range can be differentially modulated by different adaptation mechanisms. Additionally, noise was a non-ignorable factor, which could effectively modulate the neuronal dynamic range.
ABSTRACT
Distyly, a special polymorph, has evolved in many groups of angiosperms and has attracted attention since Darwin's time. Development studies on distylous taxa have helped us to understand the evolutionary process of this polymorph, but most of these studies focus on species with narrowly tubular corolla. Here, we studied the floral development of Polygonum jucundum, a distylous species with broadly open flowers, at multiple spatial scales. Results showed that the difference in stigma height between flowers of the two morphs was caused by differences in style growth throughout the entire floral development process. The observed difference in anther heights between the two morphs was because the filaments grew faster in short-styled (SS) than in long-styled (LS) flowers in the later stages of floral development. In addition, the longer styles in LS flowers than in SS flowers was because of faster cell division in the early stages of floral development. However, SS flowers had longer filaments than LS flowers primarily because of greater cell elongation. These results indicate that floral development in P. jucundum differs from that of distylous taxa with floral tubes shown in previous studies. Further, we conclude that the presence of distyly in species with open flowers is a result of convergent evolution.
Subject(s)
Flowers/anatomy & histology , Polygonum/anatomy & histology , Biological Evolution , Flowers/classification , Flowers/growth & development , Phylogeny , Pollen/physiology , Polygonum/classification , Polygonum/growth & development , Reproduction/physiology , Selection, Genetic , Species SpecificityABSTRACT
Reproductive performance of 750 adult female Forest musk deer (FMD, Moschus berezovskii) was monitored (from 2005 to 2009) on two Forest musk deer farms in Sichuan province, China. The mean (± SEM) lengths of the estrous cycle, pregnancy, and consecutive fawning intervals were 17.5 ± 0.8 d (n = 64), 182.9 ± 0.8 d (n =190), and 363.2 ± 2.4 d (n = 120), respectively. Copulation occurred from the end of October to early March, with the majority (84.1 ± 1.9%) during November and December (P < 0.05). The fawning rate was 68.7 ± 2.2% in yearling hinds and 73.3 ± 1.3% in adult hinds. Fawning occurred from the end of April to early September, with the majority (88. 9 ± 2.2%) during May and June (P < 0.005), including a peak in May (52.0 ± 1.0%). Yearling hinds fawned later (7.3 ± 1.8 d) than adult hinds. Rates of premature delivery and dystocia were 2.7 ± 0.4 and 2.0 ± 0.3%, respectively. There was a 1.07:1 female-to-male ratio at birth (P > 0.05), with 67.7% twins, but only two cases of triplets and one set of quadruplets among 537 fawns. Birth weight averaged 518.7 ± 10.3 g, ranging from 304 to 775 g (n = 240), with male fawns slightly heavier than females (521.1 ± 14.8 vs 516.9 ± 14.3 g). Postnatal and pre-weaning mortality rates were 25.0 ± 1.2 and 17.9 ± 3.1%, respectively. Postnatal mortality and urinary calculus were much more common in male fawns (P < 0.01). The mortality rate due to suppuration and dyspepsia were different (P < 0.001) between postnatal and pre-weaning periods. Due to higher mortality of male fawns, the adult sex ratio was significantly female-biased. In conclusion, captive FMD had similar seasonal patterns of copulation and fawning as wild FMD and other musk deer species.