Compact Digital Immunoassay Platform Integrating ELISA with a Lateral Flow Strip.

Background/objectives: On-site diagnosis of infection in their early stages requires assays with high sensitivities that are compact and easy to operate out of the laboratory and hospital environments. However, current assay technologies fall short of these requirements and require highly skilled technicians to set up, operate, and interpret the results.

Methods: To address these challenges, we developed and evaluated a Point-of-Care-Testing (PoCT) immunoassay platform called the D-strip.

[Survey of occupational health-related activities conducted at hospitals in the Kanto region (2020)].

Objective: To survey occupational health-related activities conducted at hospitals certified by the Japan Council for Quality Health Care in the Kanto region of Japan.

Methods: The survey tool was sent to 470 hospitals and comprised the following items: hospital size, occupational health system, infection control practices, mental health services, promotion of work system reforms, and priorities in achieving occupational health.

Results: A total of 140 hospitals completed the survey.

The extracellular loop of pendrin and prestin modulates their voltage-sensing property.

Pendrin and prestin belong to the solute carrier 26 (SLC26) family of anion transporters. Prestin is unique among the SLC26 family members in that it displays voltage-driven motor activity (electromotility) and concurrent gating currents that manifest as nonlinear cell membrane electrical capacitance (nonlinear capacitance (NLC)). Although the anion transport mechanism of the SLC26 proteins has begun to be elucidated, the molecular mechanism of electromotility, which is thought to have evolved from an ancestral ion transport mechanism, still remains largely elusive.

Real-time observation of flexible domain movements in CRISPR-Cas9.

The CRISPR-associated protein Cas9 is widely used for genome editing because it cleaves target DNA through the assistance of a single-guide RNA (sgRNA). Structural studies have revealed the multi-domain architecture of Cas9 and suggested sequential domain movements of Cas9 upon binding to the sgRNA and the target DNA These studies also hinted at the flexibility between domains; however, it remains unclear whether these flexible movements occur in solution. Here, we directly observed dynamic fluctuations of multiple Cas9 domains, using single-molecule FRET We found that the flexible domain movements allow Cas9 to adopt transient conformations beyond those captured in the crystal structures.

Crystal structures of the TRIC trimeric intracellular cation channel orthologues.

Ca release from the sarcoplasmic reticulum (SR) and endoplasmic reticulum (ER) is crucial for muscle contraction, cell growth, apoptosis, learning and memory. The trimeric intracellular cation (TRIC) channels were recently identified as cation channels balancing the SR and ER membrane potentials, and are implicated in Ca signaling and homeostasis. Here we present the crystal structures of prokaryotic TRIC channels in the closed state and structure-based functional analyses of prokaryotic and eukaryotic TRIC channels.

Spontaneous detachment of the leading head contributes to myosin VI backward steps.

Myosin VI is an ATP driven molecular motor that normally takes forward and processive steps on actin filaments, but also on occasion stochastic backward steps. While a number of models have attempted to explain the backwards steps, none offer an acceptable mechanism for their existence. We therefore performed single molecule imaging of myosin VI and calculated the stepping rates of forward and backward steps at the single molecule level.

Switch between large hand-over-hand and small inchworm-like steps in myosin VI.

Many biological motor molecules move within cells using stepsizes predictable from their structures. Myosin VI, however, has much larger and more broadly distributed stepsizes than those predicted from its short lever arms. We explain the discrepancy by monitoring Qdots and gold nanoparticles attached to the myosin-VI motor domains using high-sensitivity nanoimaging.

Simultaneous measurement of nucleotide occupancy and mechanical displacement in myosin-V, a processive molecular motor.

Adenosine triphosphate (ATP) turnover drives various processive molecular motors and adenosine diphosphate (ADP) release is a principal transition in this cycle. Biochemical and single molecule mechanical studies have led to a model in which a slow ADP release step contributes to the processivity of myosin-V. To test the relationship between force generation and ADP release, we utilized optical trapping nanometry and single molecule total internal reflection fluorescence imaging for simultaneous and direct observation of both processes in myosin-V.

Measurement system for simultaneous observation of myosin V chemical and mechanical events.

Myosin V is an actin-based processive molecular motor driven by the chemical energy of ATP hydrolysis. Although the chemo-mechanical coupling in processive movement has been postulated by separate structural, mechanical and biochemical studies, no experiment has been able to directly test these conclusions. Therefore the relationship between ATP-turnover and force generation remains unclear.

Site-directed spin labeling electron paramagnetic resonance study of the calcium-induced structural transition in the N-domain of human cardiac troponin C complexed with troponin I.

Calcium-induced structural transition in the amino-terminal domain of troponin C (TnC) triggers skeletal and cardiac muscle contraction. The salient feature of this structural transition is the movement of the B and C helices, which is termed the "opening" of the N-domain. This movement exposes a hydrophobic region, allowing interaction with the regulatory domain of troponin I (TnI) as can be seen in the crystal structure of the troponin ternary complex [Takeda, S.