Biological Microscopy Research Articles

The dry lab microscopist or prompt microscopist: do we need them?

AbstractIn modern biological microscopy, the explosion of data volume and complexity highlights the urgent need for specialised data management support roles. While traditional microscopy focuses on visual data presentation, the rapid increase in big data acquisition and data mining demands advanced handling and analysis. This gap underscores the need for “dry lab microscopists” or data experts skilled in microscopy data management, software interoperability, and AI-driven solutions. Job markets reflect this demand, pointing to the necessity for dedicated training programs. Integrating these specialists into research institutions is crucial for addressing digital data challenges and maintaining high standards in data integrity and analysis. Their role is essential for advancing research in the data-driven era.

Optimization of Sparse Camera Array Arrangement using Grid-based Method

—This study explores the application of multi-camera array technology in super-resolution (SR) imaging system. We propose an innovative method based on grid representation to optimize camera arrangements using sparse Gaussian processes and variational inference. This approach significantly enhances the image reconstruction quality of sparse camera arrays. Unlike conventional techniques that provide only qualitative conclusions, our grid-based method precisely optimizes camera positions and effectively simulates the impact of assembly errors. The optimized camera arrangement substantially improves the SR reconstruction quality of sparse array imaging systems, reducing contour jaggedness and high-frequency aliasing. Extensive simulations and experimental validations confirm the robustness and practical applicability of our method. The results demonstrate that the optimized camera arrangements can achieve high-resolution imaging with enhanced robustness against assembly errors, indicating their potential for various applications such as biological microscopy, remote sensing, and smartphone photography. This work presents a new and effective strategy for designing sparse camera array imaging systems, offering significant improvements in both image quality and system reliability.

What Are the Challenges Ahead for Training the Present and Next-Generation Microscopists in the Life Sciences (a.k.a. Structural Cell Biologists)?

Abstract Becoming a life scientist microscopist involves earning a bachelor’s degree in biology, biomedicine, or a related education program, specializing in microscopy-related areas. Advanced degrees (B.A. Hons., M.A. Res., or Ph.D.) enhance hands-on proficiencies and lay the foundation to become a microscopist or structural cell biologist. Staying updated on technological advancements, networking, and attending relevant microscopy conferences and workshops are central to the success of becoming an established, competent microscopist. Building an academic career in microscopy includes showcasing skills and proficiency in a research field. This involves teaching, scholarly dissemination, and achieving success in awards and grants, which are crucial for entry-level positions in academia. Continuous professional development in specific microscopy interests through workshops, self-education, online resources, or attaining additional certificates or diplomas is essential for academic career advancement, as the science of microscopy is not characterized by a status quo but is evolving at unprecedented speed. Tailoring education and understanding job requirements for academia, research organizations, or industry are critical decisions to align skills with career goals. In this themed contribution, we highlight key considerations for aspiring or junior microscopists to contemplate when building a successful research career in biological microscopy.

Quantum ghost imaging microscopy depth-of-field study

Quantum ghost imaging approaches have been proposed to enhance biological microscopy, for example, using 2D visible detectors to provide IR images or providing additional dimensions of spatial or spectral information. Toward the goal of making such imaging schemes practical, we compare image quality and depth-of-field between traditional images and ghost images at the same excitation levels. We measure how image quality and depth-of-field depend on the parameters of the entangled light produced using type-I spontaneous parametric down-conversion (SPDC). We use a pair of time-synchronized, photon-timing single-photon avalanche diode (SPAD) array detectors to capture two distinct microscope imaging paths simultaneously on a photon-pair-by-photon-pair basis: one in a traditional imaging pathway and the other a quantum ghost imaging pathway. We calculate the depth-of-field, resolution, contrast, and signal-to-noise ratio (SNR) through the parameter space of a β-Barium Borate (BBO) type-I bulk non-linear crystal length and angle. Our results provide a basis for choosing parameters for quantum ghost imaging with type-I SPDC sources.

In vivo visualization of environmentally relevant microplastics and evaluation of gut barrier damages in Artemia franciscana

Although irregularly-shaped label-free microplastics (MPs) are predominantly distributed in the environment, non-destructive analysis of environmentally relevant MPs in organisms is still challenging. The purpose of the study is to suggest in vivo visual evidence of the uptake and effect of environmentally relevant MPs in organism. Transparent irregularly-shaped high-density polyethylene was selected as an environmentally relevant model MP and exposed to brine shrimp (Artemia franciscana). As a result, we suggest the application of SEM/EDX and coherent anti-Stokes Raman scattering (CARS) microspectroscopy as complementary tools to secure in vivo visual evidence of irregularly-shaped unlabeled MPs in living organisms without chemical digestion for biodistribution observations. Biological transmission electron microscopy also provides how ingested MPs physically affects the digestive tract in the brine shrimp which is rarely reported. In terms of environmental implications, this study would advance ecotoxicological research on microplastic pollution by providing a cutting-edge tool for investigating the bioavailability and ecotoxicity of environmentally relevant MPs in ecosystems.

A Framework of Multi-View Machine Learning for Biological Spectral Unmixing of Fluorophores with Overlapping Excitation and Emission Spectra.

The accuracy in assigning fluorophore identity and abundance, termed spectral unmixing, in biological fluorescence microscopy images remains challenging due to the unavoidable and significant overlap in emission spectra among fluorophores. In conventional laser scanning confocal spectral microscopy, fluorophore information is acquired by recording emission spectra with a single combination of discrete excitation wavelengths. As a matter of fact, organic fluorophores have not only unique emission spectral signatures but also have unique and characteristic excitation spectra. In this paper, we propose a generalized multi-view machine learning approach, which makes use of both excitation and emission spectra to greatly improve the accuracy in differentiating multiple highly overlapping fluorophores in a single image. By recording emission spectra of the same field with multiple combinations of excitation wavelengths, we obtain data representing these different views of the underlying fluorophore distribution in the sample. We then propose a framework of multi-view machine learning methods, which allows us to flexibly incorporate noise information and abundance constraints, to extract the spectral signatures of fluorophores from their reference images and to efficiently recover their corresponding abundances in unknown mixed images. Numerical experiments on simulated image data demonstrate the method's efficacy in improving accuracy, allowing for the discrimination of 100 fluorophores with highly overlapping spectra. Furthermore, validation on images of mixtures of fluorescently labeled E. coli demonstrates the power of the proposed multi-view strategy in discriminating fluorophores with spectral overlap in real biological images.

From Blur to Brilliance: The Ascendance of Advanced Microscopy in Neuronal Cell Biology.

The intricate network of the brain's neurons and synapses poses unparalleled challenges for research, distinct from other biological studies. This is particularly true when dissecting how neurons and their functional units work at a cell biological level. While traditional microscopy has been foundational, it was unable to reveal the deeper complexities of neural interactions. However, an imaging renaissance has transformed our capabilities. Advancements in light and electron microscopy, combined with correlative imaging, now achieve unprecedented resolutions, uncovering the most nuanced neural structures. Maximizing these tools requires more than just technical proficiency. It is crucial to align research aims, allocate resources wisely, and analyze data effectively. At the heart of this evolution is interdisciplinary collaboration, where various experts come together to translate detailed imagery into significant biological insights. This review navigates the latest developments in microscopy, underscoring both the promise of and prerequisites for bending this powerful tool set to understanding neuronal cell biology.

The myth of high-resolution liquid phase biological electron microscopy.

Cryo-electron microscopy (cryo-EM) has transformed structural biology over the past 12 years, with it now being routine rather than exceptional to reach a near-atomic level of resolution for proteins and macromolecular complexes. Samples are immobilized by vitrification and this sample can be maintained at liquid nitrogen temperatures in the vacuum of the electron microscope with negligible sublimation. Due to the low electron doses needed to avoid radiation damage, averaging over tens of thousands to hundreds of thousands of particle images is used to achieve a high signal-to-noise ratio. An alternative approach has been proposed where samples are at room temperature in the liquid state, maintained in the vacuum of the electron microscope by thin film enclosures that are relatively transparent to electrons while preventing evaporation of the liquid. A paper has argued that using this liquid-phase approach, higher resolution (3.2 Å) can be achieved than using cryo-EM (3.4 Å) when imaging and reconstructing adeno-associated virus particles. I show here that these assertions are untrue, and that basic principles in mathematics and physics would need to be violated to achieve the stated resolution in the liquid state. Thus, high resolution liquid phase EM of macromolecules remains science fiction.

Molecular insights into the differences between cyanobacterial and plant LPORs and prolamellar body formation: In vitro studies

Light-dependent protochlorophyllide oxidoreductase (LPOR) has captivated the interest of the research community for decades. One reason is the photocatalytic nature of the reaction catalyzed by the enzyme, and the other is the involvement of LPOR in the formation of a paracrystalline lattice called a prolamellar body (PLB) that disintegrates upon illumination, initiating a process of photosynthetic membrane formation.In this paper, we have integrated three traditional methods previously employed to study the properties of the enzyme: molecular biology, spectroscopy, and electron microscopy. We found that for cyanobacterial LPOR, substrates binding appears to be independent of lipids, with membrane interaction primarily affecting the enzyme post-reaction, with MGDG and PG having opposite effects on SynPOR. In contrast, plant isoforms exhibit sequence alterations, rendering the enzyme effective in substrate binding mainly in the presence of anionic lipids, depending on residues at positions 122, 312, and 318. Moreover, we demonstrated that the interaction with MGDG could initially serve as enhancement of the substrate specificity towards monovinyl-protochlorophyllide (Pchlide). We have shown that the second LPOR isoforms of eudicots and monocots accumulated mutations that made these variants less and more dependent on anionic lipids, respectively. Finally, we have shown that in the presence of Pchlide, NADP+, and the lipids, plant but not cyanobacterial LPOR homolog remodel membranes into the cubic phase. The cubic phase is preserved if samples supplemented with NADP + are enriched with NADPH.The results are discussed in the evolutionary context, and the model of PLB formation is presented.

Unnatural Amino Acids for Biological Spectroscopy and Microscopy.

Due to advances in methods for site-specific incorporation of unnatural amino acids (UAAs) into proteins, a large number of UAAs with tailored chemical and/or physical properties have been developed and used in a wide array of biological applications. In particular, UAAs with specific spectroscopic characteristics can be used as external reporters to produce additional signals, hence increasing the information content obtainable in protein spectroscopic and/or imaging measurements. In this Review, we summarize the progress in the past two decades in the development of such UAAs and their applications in biological spectroscopy and microscopy, with a focus on UAAs that can be used as site-specific vibrational, fluorescence, electron paramagnetic resonance (EPR), or nuclear magnetic resonance (NMR) probes. Wherever applicable, we also discuss future directions.

EGFR inhibition with erlotinib induces membrane accumulation of aquaporin-2 via PDK1 and RSK activation

In the canonical aquaporin-2 (AQP2) signaling pathway, vasopressin (VP) binds to its V2 receptor, which in turn activates adenylate cyclase and protein kinase A (PKA), resulting in AQP2 S256 phosphorylation and accumulation of AQP2 in the membrane. The epidermal growth factor receptor (EGFR) inhibitor erlotinib also increases AQP2 S256 phosphorylation and membrane accumulation, yet it does not increase cAMP or PKA activity. We hypothesize that the ribosomal s6 kinase (RSK), a downstream effector in the EGFR-MAPK/ERK pathway, is the terminal kinase phosphorylating AQP2 in this novel PKA-independent pathway activated by erlotinib, and that the phosphoinositide dependent kinase-1 (PDK1), a well-established activator of RSK, is indispensable for erlotinib-induced AQP2 activation. Using our LLC-AQP2 cell model, we show that erlotinib-induced AQP2 membrane accumulation and S256 phosphorylation are abolished by the specific RSK inhibitor BI-D1870. RSK knockdown with siRNA also blocked AQP2 S256 phosphorylation and membrane accumulation, as did RSK knockout with CRISPR/cas9 editing. Next, rat kidney slices were incubated in Hank’s buffer with or without BI-D1870 and treated with erlotinib. BI-D1870 inhibited AQP2 membrane accumulation in collecting duct principal cells, supporting the relevance of this pathway in kidney cells in situ. An in-vitro kinase assay using purified proteins demonstrated that RSK directly phosphorylates AQP2 at the S256 residue. Additionally, erlotinib consistently increased phosphorylation of RSK T359, a residue associated with RSK’s active state. In canonical RSK activation, a phosphorylation cascade results in PDK1 binding to and activating RSK. We found that PDK1 inhibition with an experimental compound PS-222 also blocked erlotinib-induced AQP2 membrane accumulation and S256 phosphorylation. This implicates PDK1 along with RSK in the novel erlotinib-induced pathway of AQP2 traffcking. Our data show that RSK and PDK1 are terminal effectors in the novel, PKA-independent pathway of AQP2 activation induced by erlotinib. Further elaboration of this new non-canonical pathway promises to uncover potential pharmacological targets for the treatment of water balance disorders. This work was supported by the National Institutes of Health (NIH) grant DK096586 (D. Brown). P. W. Cheung was supported was supported by NIH K-award DK115901. Richard Babicz is the recipient of the Ben J Lipps Research Fellowship (American Society of Nephrology). Additional support for the Program in Membrane Biology Microscopy Core came from the Boston Area Diabetes and Endocrinology Research Center (DK057521) and the Massachusetts General Hospital (MGH) Center for the Study of Inflammatory Bowel Disease (DK043351). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Oxidative stress induced by menadione (vitamin K3) results in non-canonical AQP2 membrane traffcking in LLC-AQP2 cells

Oxidative stress affects a wide variety of cellular processes including morphology, protein traffcking, and cell death. Several studies show that reactive oxygen species (ROS) are able to pass through some water channels, and that ROS may modulate aquaporin expression and traffcking. However, a relationship between ROS status and the traffcking of aquaporin-2 (AQP2) has yet to be well-defined. To address this question, we first treated LLC-PK1 cells expressing cmyc-tagged AQP2 (LLC-AQP2 cells) for 30 min with menadione (MK3, 20 μM), an agent widely used to generate ROS in cell culture. Similar to vasopressin (VP), MK3 induced significant AQP2 accumulation in the plasma membrane of these cells. Using LLC-AQP2 cells expressing secreted soluble green fluorescent protein (ss-GFP), we revealed significantly increased vesicle exocytosis upon treatment with MK3. Surprisingly, MK3 did not affect rhodamine-labeled dextran endocytosis, suggesting that the MK3 effect is mainly due an increase in AQP2 exocytosis into the plasma membrane. Next, we studied the role of AQP2 c-terminal serine 256 phosphorylation in this process. MK3 treatment resulted in significant plasma membrane accumulation of the non-phosphorylatable AQP2 S256A mutant, whereas VP had no effect, as previously reported. To understand the contribution of protein kinase A (PKA) to MK3-mediated AQP2 traffcking, we used CRISPR-generated LLC-AQP2,koPKA cells that lack PKA isoforms. Interestingly, an increase in AQP2 membrane accumulation was still observed, suggesting that the MK3 effect is PKA-independent. By western blotting with anti-phospho-AQP2 antibodies, we found that MK3 did not affect phosphorylation of the critical S256 residue, but in contrast to VP, MK3 actually increased the phosphorylation level of S261 instead of reducing it. Finally, we showed that AQP2 accumulation in both LLC-AQP2 and LLC-AQP2 S256A cells was inhibited in the presence of glutathione (5 mM), an anti-oxidant or reducing agent. Interestingly, western blot analysis showed that glutathione abolished the MK3-induced increase of S261 AQP2 phosphorylation. In summary, our study shows that menadione (MK3) induces AQP2 membrane accumulation in LLC-AQP2 cells, suggesting a role of ROS in this process. This effect is largely due a change in AQP2 vesicle exocytosis. It does not require phosphorylation of the c-terminal S256 residue of AQP2, but MK3 does cause increased S261 phosphorylation. While incompletely understood at present, these data reveal that alternative, probably ROS-related, regulatory mechanisms can be involved in AQP2 traffcking and recycling. This work was supported by the National Institutes of Health (NIH) grant DK096586 (D. Brown). P. W. Cheung was supported was supported by NIH K-award DK115901. Richard Babicz is the recipient of the Ben J Lipps Research Fellowship (American Society of Nephrology). Additional support for the Program in Membrane Biology Microscopy Core came from the Boston Area Diabetes and Endocrinology Research Center (DK057521) and the Massachusetts General Hospital (MGH) Center for the Study of Inflammatory Bowel Disease (DK043351). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Two-Photon Microscopy for the Study of Tendons.

Two-photon microscopy has emerged as a potent tool for evaluating deep tissue cells and characterizing the alignment of the extracellular matrix (ECM) in various biological systems. This technique relies on nonlinear light-matter interactions to detect two distinct signals: the second harmonic generated (SHG) diffusion signal, which facilitates the visualization of collagen fibers and their orientation, and the near-infrared excitation signal for imaging ultraviolet excited autofluorescence. SHG imaging proves especially effective in visualizing collagen fibers due to the non-centrosymmetric crystalline structure of fibrillar collagen I. Given that tendons are matrix-rich tissues with a limited number of cells, their high collagen content makes them ideal candidates for analysis using two-photon microscopy. Consequently, two-photon microscopy offers a valuable means to analyze and characterize collagen abnormalities in tendons. Its application extends to studying tendon development, injuries, healing, and aging, enabling the comprehensive characterization of tendon cells and their interactions with the ECM under various conditions using two-photon microscopy tools. This protocol outlines the use of two-photon microscopy in tendon biology and presents an adapted methodology to achieve effective imaging and characterization of tendon cells during development and after injury. The method allows the utilization of thin microscopic sections to create a comprehensive image of the ECM within tendons and the cells that interact with this matrix. Most notably, the article showcases a technique to generate 3D images using two-photon microscopy in animal models.

An innovative sCMOS based autonomous astronomical camera dedicated to universal use for SST and other fields of optical astronomy

Creotech Instruments is advancing a game-changing sCMOS camera series. The Final Prototype Model of an astronomical camera for Space Surveillance and Tracking (SST) is in the test campaign phase. Designed for SST, NEO, and debris detection, its adaptable platform suits quantum tech and biological microscopy. Edge computing sets it apart, leveraging FPGA-based SoC for real-time processing and Linux-based pre-processing. Operating autonomously, it supports on-camera ML algorithms, revolutionizing astronomy. Data pre-processing, like frame stacking, reduces data load. This paper introduces the camera's concept, architecture, and prototype test results, emphasizing specific use cases and future product line development.

Preparation and thermal properties of nano-microcapsule and simulation heat storage application

The prevention of material leakage and improvement of thermal conductivity are very important for thermal energy storage application. In this work, nano-TiO2@n-docosane microcapsules were synthesized by the fine emulsion interface polymerization method using tetra-n-butyl titanate (TBT). This approach enhances the encapsulation rate and efficiency of phase change microcapsules. The microcapsules formation process was observed using a biological microscope. The diameter of the microcapsules decreased significantly with the increase of stirring rate. The phase transition temperature of the optimal microcapsules is 42.4 °C. The encapsulation rate and efficiency reach up to 90.7% and 91.0%, respectively. The average thermal conductivity of nano-TiO2@n-docosane microcapsules is 215% higher than that of n-docosane. SEM and infrared spectroscopy testing results confirm the successful coating of n-docosane by TiO2. Thermogravimetric analysis presents that TiO2 forms a shell, which reduces the leakage of n-docosane. The melting and solidification processes of n-docosane and nano-TiO2@n-docosane microcapsules were simulated numerically. In comparison to n-docosane, nano-TiO2@n-docosane microcapsules exhibit a 14.89% increase in peak storage power and a 12.47% increase in heat transfer coefficient during charging. Additionally, during discharging, these values rise by 3.23% and 6.46%, respectively. Nano-TiO2@n-docosane microcapsules enhance heat transfer and the charging/discharging process of phase change materials.

Machine learning traction force maps for contractile cell monolayers

Machine learning offers immense potential as a transformative tool capable of reshaping optical microscopy and quantitative modeling in cell biology. Here we exemplify this potential through the development of a generative adversarial network (GAN) designed to comprehend and predict cell traction force maps. Empowered by a hybrid dataset from traction force microscopy (TFM) and phase-field modeling (PFM), the GAN learns the intricacies of the traction force maps of contractile cells in complex chemomechanical environments, with the sole input being the phase-contrast images of the cells. The trained GAN accurately predicts collective durotaxis by leveraging the learned asymmetric traction force maps, while also unveiling the concealed correlation between substrate stiffness and cell contractility arising from mechanotransduction. Remarkably, despite its foundation in epithelial cell data, our image-learning algorithm can be extended to other contractile cell types by adjusting a single scaling factor. Our approach underscores the potential of synergizing force microscopies and biophysical models with image-based learning, thus catalyzing data-driven scientific revelations in cell mechanobiology.

Construction Strategy and Mechanism of a Novel Wood Preservative with Excellent Antifungal Effects.

Wood is a naturally porous material prone to microbial erosion and degradation in outdoor environments. Therefore, the development of an environmentally friendly wood preservative with excellent antibacterial effects and low toxicity is urgently needed. In this study, nitrogen-doped carbon quantum dots (N-CQDs) with excellent antifungal performance and fluorescent properties were synthesized using a one-step hydrothermal method with chitosan quaternary ammonium salt (HACC) as the raw material. The fluorescence characteristics of N-CQD preservatives can help track their position and distribution in wood. The minimum inhibitory concentration (MIC) of N-CQDs is 1.8 mg/mL, which was nearly 22 times lower than that of HACC (40.0 mg/mL) in the PDA medium. The decay resistance test demonstrated that wood treated with N-CQDs showed a considerably reduced decay degree and its mass loss rate decreased from 46 ± 0.5% to 3.8 ± 0.5%. Biological transmission electron microscopy revealed that N-CQDs effectively destroyed fungal cell structures, thereby hindering the growth of Coriolus versicolor. N-CQDs synthesized using the one-step hydrothermal method can be used as an efficient wood preservative that can effectively improve the utilization and service life of wood.

Morphometric Assessment of Sclera and Ciliary Body in Patients with Noninfectious Anterior Scleritis: A Quantitative Study Using Ultrasound Biomicroscopy

ABSTRACT Background At present, the severity and grade of anterior scleritis are judged mainly based on the area and location of involvement, whether there is necrosis, etc. Quantitative measurement of sclera and surrounding tissues will help to accurately assess the severity of scleritis and provide quantitative indicators for the choice of treatment. Methods We retrospectively analyzed the thickness of sclera and ciliary bodies detected by ultrasound biological microscopy (UBM) in noninfectious anterior scleritis patients who subsequently were treated with topical or systemic treatment, and visited our hospital from March 2014 to March 2021. Age- and sex-matched normal individuals were used as controls. Results A total of 185 patients (50 males and 135 females) with noninfectious anterior scleritis and 84 (31 males and 53 females) controls were included. In patients with noninfectious scleritis, the thickness of sclera and the ciliary body were significantly greater than those in the control group (p < 0.05). Before treatment, the thickness of sclera and the ciliary body in systemic treatment group was significantly higher than that in topical treatment group (p < 0.05). After treatment, both thicknesses of sclera and the ciliary body decreased significantly (p < 0.05). The ratio of ciliary body thickness from the site of inflammation to the normal position was significantly higher in the systemic treatment group than in the topical treatment group. Conclusions UBM quantitatively shows a decrease in AST/CBT in patients with anterior scleritis after treatment. The ratio of ciliary body thickness at the site of information to that at the normal position may be a reference for the choice of treatment.

Gross and histological studies of the female reproductive tract of the spur-winged goose (&lt;i&gt;Plectropterus gambensis&lt;/i&gt;)

The extinction of most wild avian species is becoming apprehensive and some water fowls like the spur-winged goose (Plectropterus gambensis) may represent a good model for research, to advance wildlife conservation of related avian species. Currently, there are no baseline information regarding the anatomic characteristics of the reproductive tract of this species, hence; the present study aimed at investigating the gross and histological features of the ovary and oviduct of the wild spur-winged goose. A total of five female adults spur-winged geese with ages between eight to ten months old were used for this study. The bird were purchased from a farm and transported to the Laboratory for quick decapitation and tissue processing. The birds were allowed to acclimatized for seven days, before humanely sacrificed by quick cervical dislocation and reproductive organs (ovary and oviduct) were harvested for both gross and histological evaluations. Thereafter, the ovary and oviduct were fixed, and stained with H &amp; E for light microscopic evaluation using DB2 -180M Digital Biological Microscope at different magnifications (×40, ×100, and ×400). The gross finding on the ovary revealed that it is ovoid in shape and appeared as a cluster of sacs showing yellowish to whitish follicles of different sizes and have a poorly defined oviductal segment. The oviduct appeared to be the longest part of the female reproductive tract (12.5-14.5cm). Histologically, the ovary is characterized by a membrana granulosa surrounding the oocytes at various stages of development. Also, the oviduct is by simple cuboidal to columnar ciliated secretory epithelium, and connects the ovary to the cloaca as a thin and un-convoluted tube. In conclusion, this study provided valuable information to serve as a baseline model to further research and understand the reproductive anatomy of other related domestic and wild waterfowl species.

Optical Microscopy Using the Faraday Effect Reveals in Situ Magnetization Dynamics of Magnetic Nanoparticles in Biological Samples.

The study of exogenous and endogenous nanoscale magnetic material in biology is important for developing biomedical nanotechnology as well as for understanding fundamental biological processes such as iron metabolism and biomineralization. Here, we exploit the magneto-optical Faraday effect to probe intracellular magnetic properties and perform magnetic imaging, revealing the location-specific magnetization dynamics of exogenous magnetic nanoparticles within cells. The opportunities enabled by this method are shown in the context of magnetic hyperthermia; an effect where local heating is generated in magnetic nanoparticles exposed to high-frequency AC magnetic fields. Magnetic hyperthermia has the potential to be used as a cellular-level thermotherapy for cancer, as well as for other biomedical applications that target heat-sensitive cellular function. However, previous experiments have suggested that the cellular environment modifies the magnetization dynamics of nanoparticles, thus dramatically altering their heating efficiency. By combining magneto-optical and fluorescence measurements, we demonstrate a form of biological microscopy that we used here to study the magnetization dynamics of nanoparticles in situ, in both histological samples and living cancer cells. Correlative magnetic and fluorescence imaging identified aggregated magnetic nanoparticles colocalized with cellular lysosomes. Nanoparticles aggregated within these lysosomes displayed reduced AC magnetic coercivity compared to the same particles measured in an aqueous suspension or aggregated in other areas of the cells. Such measurements reveal the power of this approach, enabling investigations of how cellular location, nanoparticle aggregation, and interparticle magnetic interactions affect the magnetization dynamics and consequently the heating response of nanoparticles in the biological milieu.