Calponin homology domain containing kinesin, KIS1, regulates chloroplast stromule formation and immunity.

Chloroplast morphology changes during immunity, giving rise to tubule-like structures known as stromules. Stromules extend along microtubules and anchor to actin filaments along nuclei to promote perinuclear chloroplast clustering. This facilitates the transport of defense molecules/proteins from chloroplasts to the nucleus. Evidence for a direct role for stromules in immunity is lacking since, currently, there are no known genes that regulate stromule biogenesis. We show that a calponin homology (CH) domain containing kinesin, KIS1 (kinesin required for inducing stromules 1), is required for stromule formation during TNL [TIR (Toll/Interleukin-1 receptor)-type nucleotide-binding leucine-rich repeat]-immune receptor-mediated immunity. Furthermore, KIS1 is required for TNL-mediated immunity to bacterial and viral pathogens. The microtubule-binding motor domain of KIS1 is required for stromule formation while the actin-binding, CH domain is required for perinuclear chloroplast clustering. We show that KIS1 functions through early immune signaling components, EDS1 and PAD4, with salicylic acid-induced stromules requiring KIS1. Thus, KIS1 represents a player in stromule biogenesis.

QUANTIFYING ACTIN FILAMENTS IN MICROSCOPIC IMAGES USING KEYPOINT DETECTION TECHNIQUES AND A FAST MARCHING ALGORITHM.

The actin filament plays a fundamental role in numerous cellular processes such as cell growth, proliferation, migration, division, and locomotion. The actin cytoskeleton is highly dynamical and can polymerize and depolymerize in a very short time under different stimuli. To study the mechanics of actin filament, quantifying the length and number of actin filaments in each time frame of microscopic images is fundamental. In this paper, we adopt a Convolutional Neural Network (CNN) to segment actin filaments first, and then we utilize a modified Resnet to detect junctions and endpoints of filaments. With binary segmentation and detected keypoints, we apply a fast marching algorithm to obtain the number and length of each actin filament in microscopic images. We have also collected a dataset of 10 microscopic images of actin filaments to test our method. Our experiments show that our approach outperforms other existing approaches tackling this problem regarding both accuracy and inference time.

Romer Labs RapidChek®Listeria monocytogenes Test System for the Detection of L. monocytogenes on Selected Foods and Environmental Surfaces.

The Romer Labs RapidChek® Listeria monocytogenes test system (Performance Tested Method 011805) was validated against the U.S. Department of Agriculture-Food Safety and Inspection Service Microbiology Laboratory Guidebook (USDA-FSIS/MLG), U.S. Food and Drug Association Bacteriological Analytical Manual (FDA/BAM), and AOAC Official Methods of Analysis (AOAC/OMA) cultural reference methods for the detection of L. monocytogenes on selected foods including hot dogs, frozen cooked breaded chicken, frozen cooked shrimp, cured ham, and ice cream, and environmental surfaces including stainless steel and plastic in an unpaired study design. The RapidChek method uses a proprietary enrichment media system, a 44-48 h enrichment at 30 ± 1°C, and detects L. monocytogenes on an immunochromatographic lateral flow device within 10 min. Different L. monocytogenes strains were used to spike each of the matrixes. Samples were confirmed based on the reference method confirmations and an alternate confirmation method. A total of 140 low-level spiked samples were tested by the RapidChek method after enrichment for 44-48 h in parallel with the cultural reference method. There were 88 RapidChek presumptive positives. One of the presumptive positives was not confirmed culturally. Additionally, one of the culturally confirmed samples did not exhibit a presumptive positive. No difference between the alternate confirmation method and reference confirmation method was observed. The respective cultural reference methods (USDA-FSIS/MLG, FDA/BAM, and AOAC/OMA) produced a total of 63 confirmed positive results. Nonspiked samples from all foods were reported as negative for L. monocytogenes by all methods. Probability of detection analysis demonstrated no significant differences in the number of positive samples detected by the RapidChek method and the respective cultural reference method.