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Current Biology : CB Jul 2023Interactions between different animal species are a critical determinant of each species' evolution and range expansion. Chemical, visual, and mechanical interactions...
Interactions between different animal species are a critical determinant of each species' evolution and range expansion. Chemical, visual, and mechanical interactions have been abundantly reported, but the importance of electric interactions is not well understood. Here, we report the discovery that the nematode Caenorhabditis elegans transfers across electric fields to achieve phoretic attachment to insects. First, we found that dauer larvae of C. elegans nictating on a substrate in a Petri dish moved directly to the lid through the air due to the electrostatic force from the lid. To more systematically investigate the transfer behavior, we constructed an assay system with well-controlled electric fields: the worms flew up regardless of whether a positive or negative electric field was applied, suggesting that an induced charge within the worm is related to this transfer. The mean take-off speed is 0.86 m/s, and the worm flies up under an electric field exceeding 200 kV/m. This worm transfer occurs even when the worms form a nictation column composed of up to 100 worms; we term this behavior "multiworm transfer." These observations led us to conclude that C. elegans can transfer and attach to the bumblebee Bombus terrestris, which was charged by rubbing with flower pollen in the lab. The charge on the bumblebee was measured with a coulomb-meter to be 806 pC, which was within the range of bumblebee charges and of the same order of flying insect charges observed in nature, suggesting that electrical interactions occur among different species.
Topics: Animals; Caenorhabditis elegans; Larva; Insecta; Behavior, Animal; Electricity
PubMed: 37348502
DOI: 10.1016/j.cub.2023.05.042 -
Environmental Microbiology Aug 2023Pseudomonas aeruginosa makes and secretes massive amounts of rhamnolipid surfactants that enable swarming motility over biogel surfaces. But how these rhamnolipids...
Pseudomonas aeruginosa makes and secretes massive amounts of rhamnolipid surfactants that enable swarming motility over biogel surfaces. But how these rhamnolipids interact with biogels to assist swarming remains unclear. Here, I use a combination of optical techniques across scales and genetically engineered strains to demonstrate that rhamnolipids can induce agar gel swelling over distances >10,000× the body size of an individual cell. The swelling front is on the micrometric scale and is easily visible using shadowgraphy. Rhamnolipid transport is not restricted to the surface of the gel but occurs through the whole thickness of the plate and, consequently, the spreading dynamics depend on the local thickness. Surprisingly, rhamnolipids can cross the whole gel and induce swelling on the opposite side of a two-face Petri dish. The swelling front delimits an area where the mechanical properties of the surface properties are modified: water wets the surface more easily, which increases the motility of individual bacteria and enables collective motility. A genetically engineered mutant unable to secrete rhamnolipids (ΔrhlA), and therefore unable to swarm, is rescued from afar with rhamnolipids produced by a remote colony. These results exemplify the remarkable capacity of bacteria to change the physical environment around them and its ecological consequences.
Topics: Pseudomonas aeruginosa; Mutation; Glycolipids; Surface-Active Agents
PubMed: 36964975
DOI: 10.1111/1462-2920.16373 -
Frontiers in Plant Science 2023Seed germination rate is one of the important indicators in measuring seed quality and seed germination ability, and it is also an important basis for evaluating the...
Seed germination rate is one of the important indicators in measuring seed quality and seed germination ability, and it is also an important basis for evaluating the growth potential and planting effect of seeds. In order to detect seed germination rates more efficiently and achieve automated detection, this study focuses on wild rice as the research subject. A novel method for detecting wild rice germination rates is introduced, leveraging the SGR-YOLO model through deep learning techniques. The SGR-YOLO model incorporates the convolutional block attention module (efficient channel attention (ECA)) in the Backbone, adopts the structure of bi-directional feature pyramid network (BiFPN) in the Neck part, adopts the generalized intersection over union (GIOU) function as the loss function in the Prediction part, and adopts the GIOU function as the loss function by setting the weighting coefficient to accelerate the detection of the seed germination rate. In the Prediction part, the GIOU function is used as the loss function to accelerate the learning of high-confidence targets by setting the weight coefficients to further improve the detection accuracy of seed germination rate. The results showed that the accuracy of the SGR-YOLO model for wild rice seed germination discrimination was 94% for the hydroponic box and 98.2% for the Petri dish. The errors of germination potential, germination index, and average germination days detected by SGR-YOLO using the manual statistics were 0.4%, 2.2, and 0.9 days, respectively, in the hydroponic box and 0.5%, 0.5, and 0.24 days, respectively, in the Petri dish. The above results showed that the SGR-YOLO model can realize the rapid detection of germination rate, germination potential, germination index, and average germination days of wild rice seeds, which can provide a reference for the rapid detection of crop seed germination rate.
PubMed: 38322421
DOI: 10.3389/fpls.2023.1305081 -
Parasites & Vectors Jul 2023Numerous bioassay methods have been used to test the efficacy of repellents for ticks, but the comparability of results across different methods has only been evaluated...
BACKGROUND
Numerous bioassay methods have been used to test the efficacy of repellents for ticks, but the comparability of results across different methods has only been evaluated in a single study. Of particular interest are comparisons between bioassays that use artificial containers (in vitro) with those conducted on a human subject (in vivo) for efficacy testing of new potential unregistered active ingredients, which most commonly use in vitro methods.
METHODS
We compared four different bioassay methods and evaluated three ingredients (DEET [N,N-Diethyl-meta-toluamide], peppermint oil and rosemary oil) and a negative control (ethanol) over a 6-h period. Two of the methods tested were in vivo bioassay methods in which the active ingredient was applied to human skin (finger and forearm bioassays), and the other two methods were in vitro methods using artificial containers (jar and petri dish bioassays). All four bioassays were conducted using Ixodes scapularis nymphs. We compared the results using nymphs from two different tick colonies that were derived from I. scapularis collected in the US states of Connecticut and Rhode Island (northern origin) and Oklahoma (southern origin), expecting that ticks of different origin would display differences in host-seeking behavior.
RESULTS
The results between bioassay methods did not differ significantly, even when comparing those that provide the stimulus of human skin with those that do not. We also found that tick colony source can impact the outcome of repellency bioassays due to differences in movement speed; behavioral differences were incorporated into the assay screening. DEET effectively repelled nymphs for the full 6-h duration of the study. Peppermint oil showed a similar repellent efficacy to DEET during the first hour, but it decreased sharply afterwards. Rosemary oil did not effectively repel nymphs across any of the time points.
CONCLUSIONS
The repellency results did not differ significantly between the four bioassay methods tested. The results also highlight the need to consider the geographic origin of ticks used in repellency bioassays in addition to species and life stage. Finally, our results indicate a limited repellent efficacy of the two essential oils tested, which highlights the need for further studies on the duration of repellency for similar botanically derived active ingredients and for evaluation of formulated products.
Topics: Humans; Animals; Ixodes; DEET; Biological Assay; Connecticut; Ethanol; Insect Repellents; Nymph
PubMed: 37430360
DOI: 10.1186/s13071-023-05845-7 -
Journal of the Mechanical Behavior of... Dec 2023Alginate gel scaffolds are biocompatible and biodegradable materials that have been used in a variety of tissue engineering applications. The porosity of alginate gel...
Alginate gel scaffolds are biocompatible and biodegradable materials that have been used in a variety of tissue engineering applications. The porosity of alginate gel scaffolds is an important property that affects their performance. However, it is difficult to predict the porosity of alginate gel scaffolds accurately. In this study, a GA-coupled ANN model was developed to predict the porosity of alginate gel scaffolds. The model was trained on a dataset of 107 scaffolds with known porosities. The model was able to achieve a mean absolute error of 0.13, which suggests that it is able to accurately predict the porosity of alginate gel scaffolds. The alginate scaffold was fabricated by a microfluidic technique using a syringe pump and a flow device. The crosslinker solution was poured into the Petri dish to crosslink the polymer to the gel structure. The Archimedes method was used to determine the scaffold's apparent porosity. The artificial neural network has been used to model the porosity of the gel scaffold using the input parameters such as alginate-pluronic viscosity, surface tension, and contact angle etc. The maximum porosity was modelled to be 96.4 % using GA whereas the experimental value for the same was measured to be 92.8 ± 2 %. A 3.7% variation in the porosity was found from modelled value. To the best of our knowledge, this study is the first to develop an integrated ANN-coupled GA model to predict the maximum porosity of the gel scaffold. The result indicates that artificial intelligence has great potential for optimizing the parameters to fabricate the gel scaffold that can be used for tissue engineering applications.
Topics: Tissue Scaffolds; Porosity; Alginates; Artificial Intelligence; Tissue Engineering; Biocompatible Materials
PubMed: 37883894
DOI: 10.1016/j.jmbbm.2023.106204 -
Plant Disease Sep 2023Pecan (Carya illinoinensis) is an important economic forest crops widely cultivated in China. From June to September in both 2021 and 2022, severe leaf disease...
Pecan (Carya illinoinensis) is an important economic forest crops widely cultivated in China. From June to September in both 2021 and 2022, severe leaf disease resembling anthracnose was observed in 6.6-ha pecan orchard in Jintan (31°42'23.84″ N, 119°21'22.90″ E), Jiangsu Province. The disease severity was about 15 to 25% with 5 to 12% incidence on 100 surveyed trees of the orchard in 2022. Symptoms initially appeared as small gray-bark sunken lesions, which gradually developed to big sunken lesions with brown edges and irregular-shaped. Small fragments (4 × 4 mm) from the necrotic borders of infected leaves were surfaced sterilized, plated on potato dextrose agar (PDA) and then incubated in darkness at 25°C for 3 days. Pure cultures were obtained by monosporic isolation. Twenty-one isolates with similar characteristics were obtained from the infected leaves (isolation frequency about 90%). The upper side of colonies on the PDA plates was milky, and the reverse side was pale yellow at the center and pale white at the margin. After 10 days of growth on the PDA medium, these isolates produced spores separately. . Through electron microscopic observation, conidia were smooth walled, hyaline, aseptate, guttulate, cylindrical with rounded ends with 15 to 20.5 × 5.3 to 6.7 μm (mean 18.5 × 5.8 μm, n = 50) in size. These morphological characteristics were similar to those of the species of Colletotrichumspp (Weir et al. 2012, Fu et al. 2019). To further identify the isolates, the regions of internal transcribed spacer (ITS), actin (ACT), calmodulin (CAL), chitin synthase (CHSI), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and beta-tubulin 2 (TUB2) loci of the three representative isolates (JSJT-1, JSJT-2, and JSJT-3) were amplified and sequenced with the primer pairs ITS-1F/ITS-4, ACT-512F/ACT-783R, CL1/CL2A, CHS-79F/CHS-345R, GDF/GDR and T1/T2 primers, respectively (Weir et al. 2012). Sequences of them were deposited in GenBank under nos. OR214960 to OR214962 (ITS), OR228543 to OR228545 (ACT),OR228546 to OR228548 (CAL), OR228549 to OR228551 (CHSI), OR228552 to OR228554 (GAPDH), and OR228555 to OR228557 (TUB2). Multilocus phylogenetic analysis revealed that the three isolates and C. aenigma were clustered in the same clade. Based on the results of morphological and molecular analysis, these isolates were identified as C. aenigma. The pathogenicity of three isolates was tested on leaves of pecan seedlings. Suspensions of conidia were obtained by scraping the surface of a 10-day-old sporulated petri dish PDA cultures into sterile water. Suspensions were adjusted to a density of 2 × 106 conidia/ml with a hemocytometer.The conidial suspension of each isolate was sprayed evenly on the surface of leaves from three healthy pecan seedlings. Sterilized distilled water was used for negative controls. The pathogenicity experiment was repeated three times. Finally, all inoculated plants were kept in a light-incubator at 28°C under 100% relative humidity and 12 h photoperiod. Two weeks after inoculation, the inoculated plants developed symptoms similar to those of the original diseased plants, while controls remained asymptomatic. C. aenigma were re-isolated from from inoculated leaves. C. aenigma has been reported as the causal agent of anthracnose on several economically important plants, such as grape ( Kim et al. 2021), tree peonies (Wang et al.2023), chili (Diao et al. 2017), and pear (Fu et al. 2019), but this is the first report of C. aenigma causing anthracnose on pecan in China. Identification of C. aenigma as a pathogen of pecan is important for implementing control management strategies for pecan disease. References: Diao, Y. Z., et al. 2017. Persoonia. 38:20. Fu, M., et al. 2019. Persoonia. 42:1. Kim, J. S., et al. 2021. Plant Dis. 105:2729. Weir, B. S., et al. 2012. Stud. Mycol.. 73:115. Wang, Y. L., et al. 2023. Plant Dis. 107(4):1242. The author(s) declare no conflict of interest. Keywords: Colletotrichum aenigma, Anthracnose, Carya illinoinensis, Pathogenicity.
PubMed: 37721520
DOI: 10.1094/PDIS-07-23-1378-PDN -
Plant Disease Aug 2023Bletilla striata (Thunb.) is a perennial herb plant of the orchidaceous family and is used as an ornamental plant in Europe and the United States. Furthermore, it is...
Bletilla striata (Thunb.) is a perennial herb plant of the orchidaceous family and is used as an ornamental plant in Europe and the United States. Furthermore, it is important as traditional Chinese medicine (TCM) in East Asian countries, such as China, Japan, Korea, Mongolia, and Myanmar (Gou et al. 2022). In April 2023, a severe disease similar to gray mold occurred in a B. striata plantation in Anqing, Anhui province, China (N30°27'15″, E116°18'32″), causing disease on about 20% of the plants in the field. Early symptoms were characterized by brown spots or stripes on the leaves of B. striata, and as the disease progressed, large brown irregular spots appeared. Eventually disease spots coalesced, covering the entire leaf surface and causing leaf death. A gray mildew layer was observed on the senescent leaves. To investigate the causal agent, 10 plants with typical symptoms were collected from the field. Leaf pieces (5 × 5 mm) from the border of infected areas were soaked in 75% ethanol for 10 seconds, and then transferred into 0.1% mercury bichloride for three min, rinsed three times with sterile water, and transferred to PDA at 25 °C for three days. Pure cultures were obtained by single spore isolation, and the resulting colonies were morphologically similar, indicating a single pathogen, of which the representative BSFC-7 was selected for further study. BSFC-7 colonies were initially white to gray-brown, and cottony aerial hyphae grew over the entire petri dish after five days of incubation. Grayish, branched conidiophores and their terminal unicellular conidia were observed under a microscope after additional two days at 25 °C. Conidia were colorless or gray, elliptical or oval, and 7.06-12.54 × 8.33-13.55 μm (n=30). Sclerotia appeared in BSFC-7 culture up to about two weeks and were black, hard, and round or irregularly shaped (0.81-4.32 × 0.97-5.68 mm, n=20). The morphological characteristics fit the description of Botrytis cinerea (Li et al. 2016). To further identify the species, genomic DNA of BSFC-7 was extracted. PCR analysis was performed with species-specific primer pairs C729+/C729- and two nuclear genes G3PDH and RPB2 with their corresponding primer pairs G3PDH-F/G3PDH-R and RPB2-F/RPB2-R (Rigotti et al. 2002; Aktaruzzaman et al. 2018). The sequences for all three PCR products of C729, G3PDH, and RPB2 (GenBank accession nos. OR287069, OR255923, and OR255924 respectively) exhibited 99 to 100% similarity with other B. cinerea isolates. In the pathogenicity test, detached leaves of B. striata were inoculated with the BSFC-7 isolate. The leaves were soaked in sodium hypochlorite (1%) for two min, washed with sterile distilled water, and then inoculated with 10 µl of conidial suspension (106 conidia/ml). Sterile water was used as control and samples were incubated at 25 °C. After three days, all leaves inoculated with conidia showed dark brown water-soaked lesions similar to those observed in the field, while the control leaves remained healthy. The pathogen was re-isolated from the affected leaves, fulfilling Koch's postulates. B. cinerea is a common pathogen on a wide range of host plant species worldwide and has been reported to infect B. striata in Yunnan province, China (Romanazzi and Feliziani 2014; Zhang et al. 2020). To our knowledge, this is the first report of B. cinerea causing leaf spots on B. striata in Anhui province, China. This study will provide a basis for controlling the prevalence and economic losses of gray mold on B. striata.
PubMed: 37642545
DOI: 10.1094/PDIS-07-23-1384-PDN -
Lab on a Chip Jul 2023Digital droplet reactors have become a valuable tool for the analysis of single cells, organisms, or molecules by discretising reagents into picolitre or nanolitre...
Digital droplet reactors have become a valuable tool for the analysis of single cells, organisms, or molecules by discretising reagents into picolitre or nanolitre volumes. However, DNA-based assays typically require processing of samples on the scale of tens of microlitres, with the detection of as few as one or as many as a hundred thousand fragments. Through the present work, we introduce a flow-focusing microfluidic device that produces 120 picolitre core-shell beads, which are assembled into a monolayer in a Petri dish for visualization and analysis. The bead assembly is subjected to polymerase chain reaction (PCR) amplification and fluorescence detection to digitally quantify the DNA concentration of the sample. We use a low-cost 21-megapixel digital camera and macro lens to capture wide-field fluorescence images with a 10-30 mm field-of-view at magnifications ranging from 5× to 2.5×. A customised Python script analysed the acquired images. Our study demonstrates the ability to perform digital PCR analysis of the entire bead assembly through end-point imaging and compare the results with those obtained through RT-qPCR.
Topics: DNA; Polymerase Chain Reaction
PubMed: 37313835
DOI: 10.1039/d3lc00337j -
Veterinary Parasitology, Regional... Aug 2023This study aimed to evaluate the use of different adhesive substances in an method to monitor the development of C. felis felis eggs. Three adhesive substances were...
This study aimed to evaluate the use of different adhesive substances in an method to monitor the development of C. felis felis eggs. Three adhesive substances were selected: cyanoacrylate, stick glue, and liquid silicone. The eggs were obtained from a laboratory colony and placed on a thin layer of adhesive substance on the lid of a Petri dish to prevent contact with the larval growth substrate. One hundred eggs were used for each adhesive substance. The development of the eggs was monitored for three consecutive days, during which larval hatching and egg characteristics were observed. Of the 100 eggs incubated for each adhesive substance, 64, 51, and 76 larvae hatched and survived from the stick glue, cyanoacrylate, and liquid silicone plates, respectively. After 30 days of incubation, 59, 45, and 68 hatched adults were observed, respectively, in these groups. The mean hatching of larvae and adults between the liquid silicone and cyanoacrylate groups differed statistically (p < 0.05). This study demonstrated positive results, and that liquid silicone was the most easily applicable adhesive substance on the plate and interfered less with egg development, therefore having the best larval recovery compared to incubated eggs compared to the other substances.
Topics: Animals; Siphonaptera; Ctenocephalides; Brazil; Larva
PubMed: 37451757
DOI: 10.1016/j.vprsr.2023.100899 -
Frontiers in Robotics and AI 2024Oral administration is a convenient drug delivery method in our daily lives. However, it remains a challenge to achieve precise target delivery and ensure the efficacy...
Oral administration is a convenient drug delivery method in our daily lives. However, it remains a challenge to achieve precise target delivery and ensure the efficacy of medications in extreme environments within the digestive system with complex environments. This paper proposes an oral multilayer magnetic hydrogel microrobot for targeted delivery and on-demand release driven by a gradient magnetic field. The inner hydrogel shells enclose designated drugs and magnetic microparticles. The outer hydrogel shells enclose the inner hydrogel shells, magnetic microparticles, and pH neutralizers. The drug release procedure is remotely implemented layer-by-layer. When the required gradient magnetic field is applied, the outer hydrogel shells are destroyed to release their inclusions. The enclosed pH neutralizers scour the surrounding environment to avoid damaging drugs by the pH environment. Subsequently, the inner hydrogel shells are destroyed to release the drugs. A set of experiments are conducted to demonstrate the wirelessly controllable target delivery and release in a Petri dish and biological tissues. The results demonstrated attractive advantages of the reported microrobot in microcargo delivery with almost no loss, remote controllable release, and drug protection by the pH neutralizers. It is a promising approach to advance next-generation precision oral therapies in the digestive system.
PubMed: 38680620
DOI: 10.3389/frobt.2024.1392297