50 Years of Image Analysis

Microtubules are core components of the eukaryotic cytoskeleton with essential roles in cell division, shaping, motility and intracellular transport. Despite their functional heterogeneity, microtubules have a highly conserved structure made from almost identical molecular building blocks: the tubulin proteins. Alternative tubulin isotypes and a variety of post-translational modifications control the properties and functions of the microtubule cytoskeleton, a concept known as the 'tubulin code'. Here we review the current understanding of the molecular components of the tubulin code and how they impact microtubule properties and functions. We discuss how tubulin isotypes and post-translational modifications control microtubule behaviour at the molecular level and how this translates into physiological functions at the cellular and organism levels. We then go on to show how fine-tuning of microtubule function by some tubulin modifications can affect homeostasis and how perturbation of this fine-tuning can lead to a range of dysfunctions, many of which are linked to human disease.

/pdf/the-tubulin-code-and-its-role-in-controlling-microtubule-13ooa1q7rl.pdf

The tubulin code and its role in controlling microtubule properties and functions.

Infrared photodetectors are currently subject to a rapidly expanding application space, with an increasing demand for compact, sensitive and inexpensive detectors. Despite continued advancement, technological factors limit the widespread usage of such detectors, specifically, the need for cooling and the high costs associated with processing of iii–v/ii–vi semiconductors. Here, black phosphorous (bP)/MoS2 heterojunction photodiodes are explored as mid-wave infrared (MWIR) detectors. Although previous studies have demonstrated photodiodes using bP, here we significantly improve the performance, showing that such devices can be competitive with conventional MWIR photodetectors. By optimizing the device structure and light management, we demonstrate a two-terminal device that achieves room-temperature external quantum efficiencies (ηe) of 35% and specific detectivities (D*) as high as 1.1 × 1010 cm Hz1/2 W−1 in the MWIR region. Furthermore, by leveraging the anisotropic optical properties of bP we demonstrate the first bias-selectable polarization-resolved photodetector that operates without the need for external optics.

/pdf/polarization-resolved-black-phosphorus-molybdenum-disulfide-mopmtfdc3b.pdf

Polarization-resolved black phosphorus/molybdenum disulfide mid-wave infrared photodiodes with high detectivity at room temperature

Biological processes are naturally regulated with high spatial and temporal control, as is perhaps most evident in metazoan embryogenesis Chemical tools have been extensively utilized in cell and developmental biology to investigate cellular processes, and conditional control methods have expanded applications of these technologies toward resolving complex biological questions Light represents an excellent external trigger since it can be controlled with very high spatial and temporal precision To this end, several optically regulated tools have been developed and applied to living systems In this review we discuss recent developments of optochemical tools, including small molecules, peptides, proteins, and nucleic acids that can be irreversibly or reversibly controlled through light irradiation, with a focus on applications in cells and animals

Optochemical Control of Biological Processes in Cells and Animals.

Black phosphorus is an infrared layered material. Its bandgap complements other widely studied two-dimensional materials: zero-gap graphene and visible/near-infrared gap transition metal dichalcogenides. Although highly desirable, a comprehensive infrared characterization is still lacking. Here we report a systematic infrared study of mechanically exfoliated few-layer black phosphorus, with thickness ranging from 2 to 15 layers and photon energy spanning from 0.25 to 1.36 eV. Each few-layer black phosphorus exhibits a thickness-dependent unique infrared spectrum with a series of absorption resonances, which reveals the underlying electronic structure evolution and serves as its infrared fingerprints. Surprisingly, unexpected absorption features, which are associated with the forbidden optical transitions, have been observed. Furthermore, we unambiguously demonstrate that controllable uniaxial strain can be used as a convenient and effective approach to tune the electronic structure of few-layer black phosphorus. Our study paves the way for black phosphorus applications in infrared photonics and optoelectronics. Few-layered black phosphorus offers an infrared bandgap, complementing that of graphene and transition metal dichalcogenides. Here, the authors investigate the thickness- and strain-dependent electronic structure of black phosphorus using polarised infrared spectroscopy.

/pdf/infrared-fingerprints-of-few-layer-black-phosphorus-ibunnkyrc5.pdf

Infrared fingerprints of few-layer black phosphorus.

Ganoderma lucidum or Lingzhi is a fungus species widely known as a traditional medicine. Exploring the beneficial peptides by hydrolysis using pepsin and trypsin has been extensively performed to identify new bioactive natural products. A multifunctional peptide that expresses potential scavenging activity and tyrosinase inhibition is valuable in therapeutic and cosmetic applications. This study aimed to identify and investigate the effects of a novel multifunctional peptide from Lingzhi on the melanogenic enzymes in melanoma cells by a targeted-proteomics approach. The multifunctional peptide was de novo sequenced by LC-MS/MS to be NH2-PVRSSNCA-CO2H (octapeptide). This sequence was chemically synthesized by solid-phase peptide synthesis (SPPS). The antioxidant ability of the synthesized octapeptide was measured by the DPPH, ABTS, and FRAP assays. The results showed that the peptide exhibited an antioxidant activity equal to 0.121 ± 0.01 mg equivalent to ascorbic acid, 0.173 ± 0.03 mg equivalent to gallic acid, and 2.21 ± 0.23 mM equivalent to FeSO4, respectively, which is comparable to these well-known antioxidants. The proteomics approach identified a total of 5804 proteins and several pathways involved in the effects of the octapeptide in melanoma cells. Targeted proteomics revealed three specific proteins associated with pigmentation including Rab29, Dct, and Tyrp1. The Rab29 and Dct were upregulated whereas Tyrp1 was downregulated in the octapeptide treatment group. These findings could be used in the understanding of the molecular functions of the multifunctional octapeptide on melanogenic enzymes, supporting its potential as a therapeutic and cosmetic ingredient.

/pdf/discovery-of-a-multifunctional-octapeptide-from-lingzhi-with-h7hdj2z1.pdf

Discovery of a Multifunctional Octapeptide from Lingzhi with Antioxidant and Tyrosinase Inhibitory Activity

Protein-protein interactions are highly dynamic biological processes that regulate various cellular reactions. They exhibit high specificity and spatiotemporal control in order to efficiently utilize finite resources in a cellular compartment. Photoactivatable chemically inducible dimerization (pCID) has emerged as an attractive technique in the scientific community, leading to the development of systems that can be activated with various wavelengths of light in order to manipulate processes on biologically relevant scales with molecular specificity. These systems can be modified to control various protein functions with unprecedented precision and spatiotemporal resolution. In this chapter, we describe an optogenetic platform that provides reversible control over dimerization of genetically tagged proteins using orthogonal wavelengths of light. We demonstrate photoactivation and photo-reversal of protein localization and transport. Mitosis is manipulated by activating and silencing the spindle assembly checkpoint through recruitment and release of proteins from kinetochores.

Reversible optogenetic control of protein function and localization.

This study investigates how a new substance, composed of ethyl ascorbic acid and citric acid, affects the shear bond strength (SBS) of metal brackets when bonded to bleached teeth. Forty maxillary premolar teeth were used and randomly placed into four groups (n = 10): the control group did not undergo bleaching; the remaining groups underwent bleached using 35% hydrogen peroxide. In group A, 37% phosphoric acid was applied after bleaching. In group B, 10% sodium ascorbate was used for ten minutes before 37% phosphoric acid. In group C, 35%3-O-ethyl-l-ascorbic acid plus 50% citric acid solution (35EA/50CA) was applied for 5 min. The subgroups were bonded immediately after bleaching. The SBS was determined with a universal testing machine and analyzed using one-way ANOVA and then Tukey’s HSD tests. Adhesive remnant index (ARI) scores were determined with a stereomicroscope and analyzed with a chi-squared test. The significance level was 0.05. Group C demonstrated significantly higher SBS values than group A (p < 0.001), but was not significantly different than the control group or group C (p > 0.05). The ARI scores were significantly different among the groups (p < 0.001). In conclusion, enamel surface treatment using 35EA/50CA improved the reduced SBS to an acceptable clinical level and reduced the clinical chair time.

/pdf/one-step-surface-treatment-reagent-35-3-o-ethyl-l-ascorbic-1yx9e7p2.pdf

One-Step Surface-Treatment Reagent (35% 3-O-Ethyl-l-ascorbic Acid Plus 50% Citric Acid Solution) Restores the Shear Bond Strength of Metal Brackets Bonded to Bleached Human Enamel: An In Vitro Study

Light-emitting plants (LEPs) provides light in areas without electricity. The phosphorescent compound was used as a lighting material for LEP development. However, using the phosphorescent compound for LEPs development required optimization and phytotoxicity evaluation. Strontium aluminate (SrAl2O4) is a phosphorescent compound that can glow for a long time and is easily recharged by visible light. In this study, using SrAl2O4 to develop LEPs was evaluated. Additionally, plant stress under SrAl2O4 was investigated. Metabolomic analysis can explain the possible mechanism of plants' stress under SrAl2O4. After, injecting 3 mL of 5% (w/v) SrAl2O4 products 1, 2, and 3 into the stem of Ipomoea aquatica, the result showed that SrAl2O4 products 2 and 3 caused oxidative stress. The metabolomic analysis also indicated that I. aquatica responded to SrAl2O4 product 1 by increasing pipecolic acid and salicylic acid, while I. aquatica injected with SrAl2O4 products 2 and 3 showed a decrease in salicylic acid around 0.005 and 0.061-fold, respectively, compared to control plants. and an excess accumulation of MDA around 10.00-12.00 µmol g-1 FW. A 15% concentration of SrAl2O4 can be used for LEPs development, enabling photoemission 18-fold for 50 minutes. SrAl2O4 product 1 has the potential to be a material for LEPs.

Chanat Aonbangkhen

Papers

Discovery of a Multifunctional Octapeptide from Lingzhi with Antioxidant and Tyrosinase Inhibitory Activity

Reversible optogenetic control of protein function and localization.

One-Step Surface-Treatment Reagent (35% 3-O-Ethyl-l-ascorbic Acid Plus 50% Citric Acid Solution) Restores the Shear Bond Strength of Metal Brackets Bonded to Bleached Human Enamel: An In Vitro Study

Possibility to apply strontium aluminate to produce light-emitting plants: efficiency and safety.

Schomburginones A‒J, geranylated benzophenones from the leaves of Garcinia schomburgkiana and their cytotoxic and anti-inflammatory activities.