Laser Synthesis of Nanostructured Glass for Selective Cell Proliferation or Apoptosis

The state-of-the-art in synthesis of nanostructured cell and contra-cell surfaces relies on techniques that utilize elaborate precursor chemicals, catalysts, or vacuum conditions, and any combination thereof. Two types of nanostructures, Na2O nanotips and SiO2 nanofibers, have been fabricated on soda-lime glass using ultrafast laser ablation. Control over nanotip width was demonstrated via laser dwell time and a new tip formation mechanism is proposed. The nanofibers generated in this work display a level of nanomorphology unseen in other fiber fabrication methods. The resulting fibers show striking morphological similarity to proteins that comprise the natural extra cellular matrix. The interaction of both nanostructures with NIH 3T3 fibroblasts was explored by incubating nanostructured glass with fibroblasts over periods of 12 hours, 1 day, or 1 week. Nanotip structures appeared to induce apoptosis in cells while nanofibers influenced cells to display unique, healthy characteristics such as preferential adhesion to nanofibers and increased microvilli generation.

Laser Synthesis of Nanostructured Glass for Selective Cell Proliferation or Apoptosis

The state-of-the-art in synthesis of nanostructured cell and contra-cell surfaces relies on techniques that utilize elaborate precursor chemicals, catalysts, or vacuum conditions, and any combination thereof. Two types of nanostructures, Na2O nanotips and SiO2 nanofibers, have been fabricated on soda-lime glass using ultrafast laser ablation. Control over nanotip width was demonstrated via laser dwell time and a new tip formation mechanism is proposed. The nanofibers generated in this work display a level of nanomorphology unseen in other fiber fabrication methods. The resulting fibers show striking morphological similarity to proteins that comprise the natural extra cellular matrix. The interaction of both nanostructures with NIH 3T3 fibroblasts was explored by incubating nanostructured glass with fibroblasts over periods of 12 hours, 1 day, or 1 week. Nanotip structures appeared to induce apoptosis in cells while nanofibers influenced cells to display unique, healthy characteristics such as preferential adhesion to nanofibers and increased microvilli generation.

Serotonin and MAOA enable the organizer and tip dominance in Dictyostelium

The embryonic organizer is essential to determine one or more developmental polarities during chordate early development1,2. Functionally similar organizers also occur in more ancient animals3, and even in some protozoans such as Dictyostelium, in which the tip of the multicellular mound acts as an organizer4, establishing the main developmental axis, and regulating the size of the fruiting body5. However, our understanding of how the Dictyostelium organizer arises, and functions, is limited. Here we show that monoamine oxidase A (maoA), which degrades serotonin, confers the fate of an organizer to the Dictyostelium tip. Conversely, once a tip has formed, serotonin contributes to tip dominance. It inhibits further tip formation, and thus ensures the mound retains the size specified during an earlier developmental stage. Reducing the expression of maoA through RNA interference or by adding MAO specific inhibitors suppresses tip formation. Conversely, adding human MAOA enzyme, or an antagonist or antibodies against serotonin, restores tip formation in maoA knockdowns. Overexpression of maoA or adding a serotonin antagonist to the wildtype induces multiple tips from a single mound in a dose dependent manner. Using an array of genetic and molecular techniques, we show that serotonin’s inhibition of cAMP signalling and cell-cell adhesion is the basis of its regulation of tip formation. Our study demonstrates that serotonin, recently appreciated for its developmental roles in widespread phyla6, also has a novel and ancient role in the formation and function of an organizer.

Molecular Mechanisms of Conidial Germination in Aspergillus spp.

SUMMARY Aspergilli produce conidia for reproduction or to survive hostile conditions, and they are highly effective in the distribution of conidia through the environment. In immunocompromised individuals, inhaled conidia can germinate inside the respiratory tract, which may result in invasive pulmonary aspergillosis. The management of invasive aspergillosis has become more complex, with new risk groups being identified and the emergence of antifungal resistance. Patient survival is threatened by these developments, stressing the need for alternative therapeutic strategies. As germination is crucial for infection, prevention of this process might be a feasible approach. A broader understanding of conidial germination is important to identify novel antigermination targets. In this review, we describe conidial resistance against various stresses, transition from dormant conidia to hyphal growth, the underlying molecular mechanisms involved in germination of the most common Aspergillus species, and promising antigermination targets. Germination of Aspergillus is characterized by three morphotypes: dormancy, isotropic growth, and polarized growth. Intra- and extracellular proteins play an important role in the protection against unfavorable environmental conditions. Isotropically expanding conidia remodel the cell wall, and biosynthetic machineries are needed for cellular growth. These biosynthetic machineries are also important during polarized growth, together with tip formation and the cell cycle machinery. Genes involved in isotropic and polarized growth could be effective antigermination targets. Transcriptomic and proteomic studies on specific Aspergillus morphotypes will improve our understanding of the germination process and allow discovery of novel antigermination targets and biomarkers for early diagnosis and therapy.

Micro-Cantilever Displacement Detection Based in Optical Fiber Tip

This work demonstrates the potential of combining a microsphere with a tip for the functionality of the contact sensor. This sensor consists of a tip aligned with the fiber core and a microsphere, which appears during tip formation. This new structure was produced using the electric arc machine. The sensor operation consists of the variation of the tip curvature, which causes a variation of the optical paths and, consequently, a change in the output signal. The study of this micro-cantilever consisted of an exploration of the contact mode. In addition, the sensor was characterized by temperature, which shows very low sensitivity and vibration. This last characterization was performed with two configurations parallel and perpendicular to the oscillating surface. The perpendicular case showed higher sensitivity and has an operating band of 0 Hz to 20 kHz. In this configuration, for frequencies up to 2 Hz, the intensity varies linearly with the frequencies and with a sensitivity of 0.032 ± 0.001 (Hz−1). For the parallel case, the operating band was from 1.5 kHz to 7 kHz.