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Channel: Microscopy and Analysis

Bond making and breaking imaged in action

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Bond making and breaking imaged in action

Rebecca Pool

Published date: 
Wednesday, January 22, 2020 - 10:45
Image: Dirhenium molecules within carbon nanotubes.
 
Using state-of-the-art TEM, UK- and Germany-based researchers have imaged bonding in molecules at the atomic scale. 
 
While atomic force microscopy and scanning tunnelling microscopy have resolved atomic positions and bond lengths, filming chemical bonds breaking or forming with spatio-temporal continuity, in real time, has remained one of the greatest challenges of science - until now.
 
Professor Andrei Khlobystov from the University of Nottingham, UK, Professor Ute Kaiser from the University of Ulm, and colleagues, used chromatic and spherical aberration-corrected Sub Angstrom Low-Voltage Electron Microscopy (SALVE), to image metal–metal bonding in dirhenium molecules.
 
Based on a FEI Titan 80-300 TEM, SALVE uses a custom spherical and chromatic aberration correction system to eliminate the chromatic aberrations at low voltages, providing high-resolution electron energy loss spectroscopy and energy-filtered TEM.
 
The instrument operates at acceleration voltages between 20 kV and 80 kV, and at 40 kV the instrument's resolution is 15 times the diffraction limiting electron wavelength.
 
“To our knowledge, this is the first time when bond evolution, breaking and formation was recorded on film at the atomic scale,” says Khlobystov. “We are now pushing the frontiers of molecule imaging beyond simple structural analysis, and towards understanding dynamics of individual molecules in real time.”
 
As described in Science Advances, Khlobystov and colleagues created dirhenium molecules with unsupported Re–Re bonds using single-walled carbon nanotubes as a 'nano-test tube' while simultaneously imaging the structure and dynamics of the single atoms in real time.
 
“Moving freely at room temperature along the SWNT, the Re2 molecules have been shown to switch bond order between one, two, and four,” reports Khlobystov. “We could follow the process of dissociation and reformation of intermetallic bonds in individual Re2 molecules.”
 
The researchers are known for their pioneering use of TEM to capture chemical reactions at the single-molecule level as well as the dynamics of metal atoms in nanocatalysts, using carbon as miniature test tubes for atoms.
 
“Nanotubes help us to catch atoms or molecules, and to position them exactly where we want,” explains Khlobystov. “In this case we trapped a pair of rhenium atoms bonded together to form Re2. Because rhenium has a high atomic number it is easier to see in TEM than lighter elements, allowing us to identify each metal atom as a dark dot.”
 
“As we imaged these diatomic molecules... we observed the atomic-scale dynamics of Re2 adsorbed on the graphitic lattice of the nanotube and discovered that the bond length changes in Re2 in a series of discrete steps,” adds Kaiser.
 
A molecule made of two rhenium atoms (dark spots) travels around two carbon nanotubes (lighter lattice of spots), settling into the gap between the nanotubes. When the atoms separate by a larger distance, the bond between the atoms is broken, and then later reforms, [University of Nottingham].
 
Khlobystov and colleagues use the electron beam to image atomic positions and also activate chemical reactions, so they can record movies of molecules, and as is the case here, film two atoms bonded together and 'walking' along the nanotube.
 
“It was surprisingly clear how the two atoms move in pairs, clearly indicating a bond between them,” highlights Dr Kecheng Cao from Ulm University. “Importantly, as Re2 moves down the nanotube, the bond length changes, indicating that the bond becomes stronger or weaker depending on the environment around the atoms.”
 
“Transition metals, such as Re, can form bonds of different order, from single to quintuple bonds,” adds Dr Stephen Skowron, Postdoctoral Research Assistant at University of Nottingham. “In this TEM experiment we observed that the two rhenium atoms are bonded mainly through a quadruple bond, providing new fundamental insights into transition metal chemistry.”
 
Research is published in Science Advances.
 
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Ultrafast camera takes 1 trillion frames per second

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Ultrafast camera takes 1 trillion frames per second

Rebecca Pool

Published date: 
Wednesday, January 22, 2020 - 15:45
Image: Ultrafast photography with phase contrast microscopy captures a shockwave propagating in slow motion. [Caltech]
 
US-based researchers have combined extreme speed photography with phase contrast microscopy to image ultrafast phenomena in transparent objects, from cells to shockwaves, at picosecond resolution.
 
So-called phase-sensitive compressed ultrafast photography (pCUP) takes an incredible 1 trillion frames per second.
 
pCUP pioneer, Professor Lihong Wang, Caltech, has used the system to capture a shockwave created by a laser striking water and laser light travelling through a crystal, in a single shot.
 
"What we've done is to adapt standard phase-contrast microscopy so that it provides very fast imaging, which allows us to image ultrafast phenomena in transparent materials," says Wang.
 
As more and more researchers turn to optical imaging to capture ultrafast phenomena in transparent objects, the use of systems that provide high contrast imaging at high frame rates is rising.
 
But while phase sensitivity can provide the necessary contrast, today's detectors cannot always provide the necessary frame rates.
 
With this in mind, Wang and colleagues decided to combine phase-sensitive dark-field imaging with compressed ultrafast photography (CUP), based on the world's fastest camera that they developed just over a year ago.
 
As Wang and colleagues explain in Science, CUP uses compressed sensing theory and the streak camera technology to achieve receive-only single-shot ultrafast imaging of up to 350 frames per event at 100 billion frames/s (Gfps).
 
“Since CUP operates as a passive detector, it can be coupled to many optical imaging systems,” says Wang. “By combining CUP with dark-field microscopy, we show that pCUP can image ultrafast phase signals... at an improved speed of 1 trillion frames/s (Tfps)."
 
A pulse of laser light travels through a crystal in slow motion, as captured by a new ultrafast photography technology. [Caltech]
 
pCUP consists of two parts, a dark-field microscope system and the upgraded lossless-encoding CUP (LLE-CUP) detection system, pioneered by Wang and colleagues.
 
Unlike  other ultrafast video-imaging technologies that take a series of images in succession while repeating the events, the LLE-CUP system takes a single shot, capturing all the motion that occurs during the time that shot takes to complete.
 
In this way, LLE-CUP can capture motion that is far too fast to be imaged by more typical camera technology, including the movement of light itself.
 
To demonstrate picosecond-resolution phase-sensitive imaging, Wang and colleagues imaged the spread of a shockwave through water and also a laser pulse as it travelled through a piece of crystalline material.
 
A shockwave created by a laser striking water propagates in slow motion, as captured by a new ultrafast photography technology. [Caltech]
 
Wang says the technology is still in its early stages of development but could ultimately have uses in many fields, including physics, biology, or chemistry.
 
"As signals travel through neurons, there is a minute dilation of nerve fibres that we hope to see. If we have a network of neurons, maybe we can see their communication in real time," he points out. “In addition, because temperature is known to change phase contrast, the system may be able to image how a flame front spreads in a combustion chamber.”
 
Research is published in Science.
 

A pulse of laser light travels through a crystal in slow motion, as captured by a new ultrafast photography technology. [Caltech]

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Largest, high-resolution map of brain revealed

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Largest, high-resolution map of brain revealed

Rebecca Pool

Published date: 
Thursday, January 23, 2020 - 13:15
Image: The hemibrain connectome offers a complete picture of neurons, a central portion of the fruit fly brain. [FlyEM/Janelia Research Campus]
 
Using focused ion beam scanning electron microscopy, Google and Howard Hughes Medical Institute researchers in the US have constructed the most complete map of the fruit fly brain ever, pinpointing millions of connections between 25,000 neurons. 
 
With the entire fly brain connectome - with its 100,000 neurons - expected to be revealed by 2022, mysteries around the networks that help to form memories and underlie movements will soon be solved.
 
“This was a big bet on something people thought was almost impossible to do,” says Google researcher and former laboratory head at Janelia Research Campus, Viren Jain. “This will be the first time that we can really have a nuanced look at the organisation of a nervous system with 100,000 neurons on a synaptic scale.”
 
“This is going to change the way people do neuroscience,” adds Gerry Rubin, vice president of HHMI and executive director of Janelia Research Campus.
 
The hemibrain dataset encompasses the part of the fly brain highlighted here in blue. This region includes neurons involved in learning, navigation, smell, vision, and many other functions [FlyEM/Janelia Research Campus]
 
The connectome team, known as FlyEM, set out to image the Drosophila 'hemibrain', a central portion of the brain containing circuits associated with learning, memory, sleep and circadian rhythms.
 
By tracing the winding paths of neurons in the fly brain, scientists have revealed how these cells link up and work together, such as these neurons involved in navigation. [FlyEM/Janelia Research Campus]
 
Researchers mounted slices of brain onto custom FIB-SEM systems, in which an FEI Magnum FIB column was mounted at 90º onto a Zeiss Merlin SEM.
 
As the researchers report in bioRxiv: “We have transformed the conventional FIB-SEM from a laboratory tool that is unreliable for more than a few days to a robust volume electron microscope imaging platform with effective long-term reliability, able to perform years of continuous imaging without defects in the final image stack.”
 
“Imaging time is now the main impediment to even larger volumes, rather than FIB-SEM reliability,” they add.
 
The electron microscopes run continuously for weeks to image sections of the fly brain, and are housed in a climate-controlled vibration-proof room to minimize the risk of disruptions to data collection. [Matt Staley, Janelia Research Campus]
 
The researchers re-designed the FIB-SEM control system to boost image speed by more than ten times and expand the practical imaging volume by more than four orders of magnitude.
 
They also increased sample staining intensity to accelerate imaging and developed an algorithm to deal with image segmentation. So-called flood-filling network directly follows neurons end-to-end as it scrolls through imaging data, deciding how to extend the cell's shape based on image context and prior predictions.
 
Computer algorithms follow the threads of individual neurons through images captured by electron microscopes, and pinpoint where those neurons connect. Then, human proofreaders check the computers’ work and fill in missing pieces. [Matt Staley, Janelia Research Campus]
 
Other key advances related to image alignment, synapse detection, data storage, proofreading software and more.
 
Crucially, FlyEM, is making all data public and freely available with a website and resources designed for all levels of expertise from the expert to the merely curious.
 
In the coming weeks more papers will be released that include research on the central complex, a brain region involved in navigation, motor control, and sleep, and insights from the mushroom body, the centre of learning in the fly brain.
 
Research is published in bioRxiv.
 
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Meeting Report - CMG 31

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Author: 
C Parmenter

Meeting Report - CMG 31

Mid-November in the UK Cryo microscopy community is synonymous with the annual Cryo Microscopy Group (CMG) meeting. November 2019 was no different and saw a diverse line up of speakers share their latest achievements at the University of Nottingham with a receptive and enthustic audience. 

The first speaker Thomas Braun from the University of Basel presented his work on revolutionary cryo-EM grid preparation which uses nanolitre deposition onto EM grids for the purpose of preparing thin films of solutions. The use of a microcapilary technology for the deposition and microfluidics for solution mixing and sample extraction combine to give a very powerful sample preparation technique. Thomas presented this using the title single-cell proteomics in which he show it was possible to extract cellular contents and deposit this onto a TEM grid with a view to analysing the proteins by cryo-TEM and single particle analysis.

Following on from Braun, Nicole Hondow from the LEMAS centre at the University of Leeds, changed things up with a wonderful overview of her work using cryo techniques for materials systems characterisations. Nicole explained that she’d started using Cryo-TEM to analyse nanoparticle solutions, but then explored Cryo-STEM, EDX and EELS and was able to use traditional microanalysis techniques on these beam sensitive and hydrated systems. This is something that I’ve noticed happening more and more as the benefits of cryo-EM are fully realised by materials scientists. She also reported on some Cryo-FIB analyses that the LEMAS team had been working on with colleagues in chemical engineering. Using the FIB they’d be able to analyse fully hydrated colloidal dispersions in 3 dimensions, resulting in impressive renderings that added insight to these structures.

The CMG always has wonderful support from trade partners and this meeting was no exception, both from microscope manufacturers, cryo-stage manufacturers and accessories companies. As part of the day the organising committee has the technobyte session, a platform for the vendors to update the attendees on their latest hardware/software.

A feature of the CMG for some time has been a focus on the student / early career or those new to cryomicroscopy. Traditional poster presentations have given way to the Freeze Frames competition and this year two entrants braved the podium to show two slides of their work and explain it in two minutes. Both entrants kept to the slide and time limits (this doesn’t happen every year) and Zubair Nizamudeen was awarded first place with his work on correlating light, electron microscopy and SIMS data with Rachael Xerri as runner-up, who showed off her impressive cryo-TEM of internally complex phases of drug loaded particles.

The Freeze Frames competition winner Zubair Nizamudeen (left) and runner-up Rachael Xerri (Centre left) with members of the committee.

After the generously long lunch break, which allowed may discussions with the vendors and speakers alike, the delegates returned to the presentations for more science and were treated to a ‘how to’ in high pressure freezing (HPF) by Xavier Heiligenstein, who summarised his long standing work in the areas of HPF and attempts to perform correlative microscopy that were now bearing fruit. Heiligenstein described his attempts to freeze quicker in order to capture events happing in cells as well as the efforts to which he had gone to freeze thicker samples. Now having left Institute Curie and working for CryoCapCell as its CSO he predicted a bright and less complex future for the field of correlative cryo-microscopy.  

Last up on the list of Speakers was David Scurr who sought to educate and amuse with his title of ‘Sub-zero SIMS’. For those who aren’t familiar, SIMS is secondary ion mass spectrometry, a well-established surface characterisation technique, but David’s system isn’t any old SIMS - it has a couple of tricks up its sleeve.  These tricks come in the form of an Orbitrap and a fully functional Cryo-stage which makes it a cryo-OrbiSIMS! This combination of high spatial resolution and high mass resolution at low temperatures (native state if the sample is correctly prepared) results in Scurr having investigated samples such as cells, bacteria and skin, in which he can investigate the ion fragments from those samples and comment on their chemistry. This can be done in three dimensions as the ion beams of the system allow 3D profiling, meaning this is an incredibly powerful technique with huge-potential.  

The meeting closed on schedule and the meeting chair thanked local organisers and helpers, before wishing all attendees a safe trip home. The 32nd CMG will take place in November 2020 with the venue to be confirmed later this year.

Chris Parmenter, Editor in Chief

 

Post type: 
blog

First electron microscopy images of new coronavirus

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First electron microscopy images of new coronavirus

Rebecca Pool

Published date: 
Monday, January 27, 2020 - 19:30
Image: Novel coronavirus under the microscope [National Pathogen Library]
 
China's National Resources Bank for Pathogenic Microorganisms has released electron microscopy images of the new strain of coronavirus, which has killed at least 100 people and infected more than 4,500.
 
The first two images show the first-ever 2019-nCoV specimen obtained by medics from a patient in Wuhan on January 6.
 
First-ever 2019-nCoV coronavirus specimen from patient in Wuhan, [National Pathogen Library].
 
According to a report in China Global Television Network, the images were released alongside the virus gene sequence, separation source and the source origin.
 
First-ever 2019-nCoV coronavirus specimen from patient in Wuhan, [National Pathogen Library].
 
A third image also shows the virus, and was extracted from a different patient on January 22 in Wuhan.
 
2019-nCoV coronavirus, [National Pathogen Library].
 
The National Resources Bank hopes scientists around the world are able to conduct further research based on the shared information.
 
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The good of small things

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The good of small things

Rebecca Pool

Published date: 
Thursday, January 30, 2020 - 11:30
Image: Convcallaria captured using the ioLight fluorescence microscope. [ioLight]
 
Not so long ago, ex-technology start-up chief executives, Andrew Monk and Richard Williams, were sat in a pub wondering what to do next. Each had recently left France-based photonic microcell developer, GLOphotonics, and wanted a new challenge. 
 
Monk was mentoring staff on how to kick-start a start-up while Williams was providing consultancy on how to develop and commercialise technology. And that’s when Williams realised that the microscopy market had a gap.
 
“Richard wanted a decent quality microscope that didn’t cost the Earth and he could also travel with,” says Monk. “Great handheld USB digital microscopes were around, but these didn’t have the necessary image quality and you had to travel with a laptop and a rucksack full of equipment, such as a stand and bottom illuminator, so these devices just weren’t that portable either.” 
 
So, with this in mind, Monk and Williams set out to design and manufacture a laboratory-grade microscope that would easily fit into your pocket. Come 2014, they had established UK start-up, ioLight, filed a patent application for their novel digital portable microscope, and were soon to raise a mighty £400,000 in seed and crowd funds.
 
Kitted out: ioLight in action. [ioLight]
 
Their first product – a X400 portable microscope with 1 mm field of view and 1 micron resolution – was launched in July 2016, and sold more than thirty units, raising £20,000, within that year.
 
Fast-forward to today, and ioLight has delivered a further microscope design with 2 mm FOV as well as inverted and fluorescence versions, and has sold some 250 instruments.
 
As Monk puts it: “We had a bit of a slow start but we’ve sold three times more microscopes than we did, this time last year, and it feels like we’re now really taking off.”
 
Meet the family
The ioLight microscope is not like anything you’ve ever seen. Chiefly comprising a solid, wide stage, that provides a stable optical platform, the instrument also has a sensor unit with adjustable height that contains the lens, illuminator and integrated camera for stills and video.
 
The stage also houses a second illuminator as well as the battery, microprocessor and Wi-Fi chip. 
 
Each microscope’s low centre of gravity and stability are critical for high-resolution imaging, without additional stands, and importantly, its arm also folds into the stage, to form a flat portable unit. 
 
“A key inventive step was getting the microscope to fold so the camera is co-planar with the stage,” highlights Monk. “If something folds it isn’t always stable and we’ve seen many folding microscopes that don’t always work well, so we had to break some ba­sic engineering rules to make a hinge that could allow the instrument to fold and still have one micron resolution.” 
 
Onion skin captured with the ioLight 1mm microscope.  [ioLight]
 
The optical system – namely the camera and lens – uses high quality, but cheap, mobile phone parts. 
 
As Monk puts it: “There are billions of phones on the market so we wanted reconfigure these parts for the optical system.”
 
The eyepiece of the microscope is replaced by the screen of a tablet or mobile phone. And an app connects the mobile device to the microscope, and no WiFi infrastructure is required so the microscope works in remote locations. 
 
“Apart from the optical system which is less than 0.5% of the costs, everything else is made in the UK,” says Monk. “And we are very proud of this.” 
 
A user’s choice of ioLight microscope depends on the application. The original 1mm FOV version was designed to observe plant and animal samples at the cellular level, and can even display structures in blood cells. 
 
On location: Field work in Kazakhstan. [ioLight]
 
Researchers have already used this microscope in Kazakhstan, the Amazon, across Africa and Mount Everest as well as Antarctica. And Monk is hopeful that it will eventually be adopted to recognise malaria parasites in blood smears. 
 
“Our technology has the potential to do this, but we will need to first design our own lens to reach a resolution of perhaps 0.7 micron,” he says. “This will be more expensive but we will get there, and it could change the world.” 
 
Meanwhile the 2 mm FOV instrument targets cell counting, opaque subjects and subjects larger than 1mm. “One of our biggest markets so far has been veterinary science so with its 2 mm field of view, this is suitable for vets that need to count worm eggs,” says Monk. 
 
Similarly, aquaculture is a growing field for ioLight, with both the Centre for Environment, Fisheries and Aquaculture Science and the Fish Vet Group having tested the ioLight microscope and used it to count the numbers of, say, plankton in water samples.
 
“These microscopes can also be used to take scrapes from the gills of fish to check for parasites, such as the dangerous Gyrodactylus Salaris, within 20 minutes,” says Monk. 
 
Nematode oesophagus captured using the ioLight fluorescence microscope. [ioLight]
 
The ioLight Founder and Director is also excited about his company’s more recent inverted and fluorescence instruments.
 
He reckons the inverted microscope, which can be used inside an incubator, will showcase exactly what the portable microscopes can do to more and more researchers.
 
Meanwhile, he is also confident that his company’s low-cost fluorescence microscope will demonstrate that you don’t need an expensive instrument to perform fluorescence microscopy. 
 
“As a company, we’re getting really close to the stage that we will not need to rely on external funding,” says Monk. “Next year we expect to be profitable, and once we’re there, we are going to get our ideas into lots and lots of places.” 
 
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Speeding up crystal structure analysis

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Speeding up crystal structure analysis

Rebecca Pool

Published date: 
Friday, January 31, 2020 - 16:00
Illustration of the inner workings of a convolutional neural network that computes the probability that the input diffraction pattern belongs to a given class, such as Bravais lattice or space group. [Vecchio lab/Science]
 
Researchers at the University of California San Diego have developed a computer-based method that could make it less labour-intensive to determine the crystal structures of various materials and molecules, including alloys, proteins and pharmaceuticals.
 
The method uses a machine learning algorithm, similar to the type used in facial recognition, to independently analyse electron diffraction patterns, and do so with at least 95% accuracy.
 
The algorithm, developed by UCSD nanoengineer,Professor Kenneth Vecchio and colleagues, works with a scanning electron microscope equipped with electron backscatter diffraction.
 
A Vecchio highlights, SEM-based EBSD can be performed on large samples and analysed at multiple length scales, providing local sub-micron information mapped to centimetre scales.
 
But while these systems can determine fine-scale grain structures, crystal orientations, relative residual stress or strain, software can't yet analyse the atomic structure of the crystalline lattices present within a material.
 
Given this, this approach demands structural guesses and user input that can be time-consuming and incorrect.
 
To solve this problem, Vecchio and colleagues developed a method that uses a convolutional neural network to automatically determine the crystal structure quickly and with high accuracy.
 
The deep neural network independently analyses each diffraction pattern from a material to determine the crystal lattice, out of all possible lattice structure types, with a high degree of accuracy (greater than 95%).
 
Crucially, the method eliminates a lot of the guesswork from crystal structure determination.
 
The researchers reckon a wide range of research areas including pharmacology, structural biology, and geology are expected to benefit from using similar automated algorithms to reduce the amount of time required for crystal structural identification.
 
Research is published in Science.
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First roadmap for ovarian ageing

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First roadmap for ovarian ageing

Rebecca Pool

Published date: 
Monday, February 3, 2020 - 12:30
Image: Immunofluorescence analysis of smooth muscle cells in the ovary. [Guang-Hui Liu]
 
Researchers from the US and China have discovered, in unprecedented detail, how ovaries age in non-human primates.
 
The findings, published in Cell, reveal several genes that could be used as biomarkers and point to therapeutic targets for diagnosing and treating female infertility and age-associated ovarian diseases, such as ovarian cancer, in humans.
 
"This is the first in-depth analysis of ovarian ageing at a single-cell resolution in a non-human primate model," says Professor Juan Carlos Izpisua Belmonte, from Salk's Gene Expression Laboratory."We found that oxidative stress, the cellular stress that damages cells, is a key player in ovarian ageing. This discovery provides valuable insight into the mechanisms by which ovaries age and eventually become infertile."
 
"Our goal was to analyse each ovarian cell type along with patterns in gene expression in order to better understand exactly how ovaries age," adds Professor Jing Qu from the Chinese Academy of Sciences and former Salk research associate. "This systematic approach provides a better understanding of the mechanisms of healthy ovarian ageing."
 
The scientists compared 2,601 ovarian cells from young and old non-human primates, and identified gene activity patterns for every type of primate ovarian cell including ooctyes and granulosa cells, which surround the oocytes as they develop.
 
Similar to previous studies in rodents, the scientists observed changes in gene function related to cellular stress and cell division across the non-human primates.
 
As the oocytes and granulosa cells aged, some of the genes that fight cellular stress became less active which led to damage and impairment in function.
 
The scientists then compared the primate data with granulosa cells from healthy women ranging in age from 21 to 46 years.
 
They observed age-associated damage from cellular stress as well as cell death in the women's cells. 
 
Two key antioxidant genes (IDH1 and NDUFB10) showed decreased function, as seen in the non-human primate cells.
 
Immunofluorescence analysis of classic markers for smooth muscle cells in the ovary, including muscle filaments (green), smooth muscle proteins (red) and nuclear DNA (blue). [Guang-Hui Liu]
 
To better understand the connection between ovarian ageing and the antioxidant genes, the scientists tested what happened to the human cells when the antioxidant genes were made non-functional. 
 
They found that without IDH1 or NDUFB10, the cells appeared old and similar to the old non-human primate cells.
 
The results suggest that IDH1 and NDUFB10 play a critical role in protecting both human and non-human primate ovarian cells from cellular stress during ageing.
 
These genes represent promising biomarkers or therapeutic targets for the diagnosis and treatment of age-related decline of the ovaries.
 
"This study provides a comprehensive understanding of the specific mechanisms of primate ovarian ageing at single-cell resolution," says Professor Guang-Hui Liu, at the Chinese Academy of Sciences and former Salk research associate. "Our results will hopefully lead to the development of new tools to aid in the rejuvenation of aged ovarian cells."
 
Research is published in Cell.
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JEOL unveils Field Emission SEM

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JEOL unveils Field Emission SEM

Published date: 
Monday, February 3, 2020 - 12:45
JEOL has unveiled a Field Emission Scanning Electron Microscope with several features unique to the company’s FE SEM product line.
 
For example, NeoEngine, employs analytical intelligence for optimizing electron beam setup and tuning while embedded EDS delivers Live Analysis for real time imaging and elemental analysis.
 
At the same time, the Zeromag navigation function is said to seamlessly transition between optical imaging to nanoscale investigation with the high-powered optics of the SEM.
 
Field Emission SEM with automated analytical intelligence.
 
"JEOL’s F100 FE-SEM offers a truly revolutionary approach to address users’ high-resolution microscopy and microanalysis needs,” says Dr Natasha Erdman, FESEM Product Manager. “In a single platform JEOL combined the best electron optics with fully embedded EDS microanalysis and the powerful AI algorithms of NeoEngine to achieve the ultimate ease of use and streamlined workflow." 
 
NeoEngine corrects electron trajectories and automatically aligns the beam in real time, plus automatically corrects focus, brightness/contrast, and astigmatism.
 
The SEM achieves single-digit Angstrom resolution at low kV, ideal for ultrahigh high-resolution imaging of nanostructures, specimen surface details, biological specimens, and magnetic samples as well as elemental analysis of non-conductive and beam sensitive samples.
 
Fully embedded EDS with Live Analysis allows the user to simply select the area, mapping, line, or another type of analysis directly on the observation screen to begin automatic live display of the elements in the specified location.
 
The large specimen chamber of the JSM-F100 features multiple ports for analytical applications: EDS, WDS, EBSD, STEM, BSE, and CL.
 
An optional Soft X-ray Emission Spectrometer provides efficient and parallel collection of very low-energy X-rays while providing unprecedented chemical state analysis.
 
The JEOL JSM-F100 features an in-lens detector and energy filter, an Aperture Angle Control Lens (ACL) for superb resolution at any kV or probe current, Beam Deceleration (BD) mode for charge reduction and enhanced surface detail, and a variable pressure option for non-conductive specimens.
 
According to the company, with the introduction of JEOL’s next-generation streamlined FE SEM product line, operator controls are simplified and the functions of the SEM fully automated for optimum performance.
 
Imaging and analysis data are also quickly obtained and reported through the data management system.
 
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Resetting internal clock could help diabetes

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Resetting internal clock could help diabetes

Rebecca Pool

Published date: 
Tuesday, February 4, 2020 - 21:45
Image: Insulin-producing cells (green), and glucagon-producing cells (red). Cell nuclei in blue. [UNIGE , Dibner Lab]
 
Bioluminescence-fluorescence time-lapse microscopy has revealed a link between disturbances of the circadian clocks in pancreatic cells and type 2 diabetes.
 
After discovering this link, Dr Charna Dibner, from the University of Geneva Faculty of Medicine and at University Hospitals of Geneva, and colleagues, were also able to re-set these molecular clocks and restore insulin production, opening the door to new approaches to diabetes care.
 
As Dibner says: "The verdict is indisputable... This is the first proof of principle that repairing compromised circadian clocks may help to improve the function of the pancreatic islet hormone secretion."
 
Today, increasing evidence shows that disturbances in our internal clocks stemming from frequent time zone changes, irregular working schedules or ageing, have a significant impact on the development of metabolic diseases in human beings, including type-2 diabetes.
 
Such disturbances seem to prevent the proper functioning of the cells in the pancreatic islet that secrete insulin and glucagon, the hormones that regulate blood sugar levels.
 
By comparing the pancreatic cells of type 2 diabetic human donors with those of healthy people, researchers at the University of Geneva (UNIGE) and the University Hospitals of Geneva (HUG), Switzerland, demonstrated for the first time that the pancreatic islet cells derived from the Type 2 Diabetic human donors bear compromised circadian oscillators.
 
The disruption of the circadian clocks was associated with the perturbation of hormone secretion. 
 
Using combined bioluminescence-fluorescence time-lapse microscopy, imaging that allows tracking the molecular clock activity in living cells very precisely over time, the researchers compared the behaviour of pancreatic cell of type-2 diabetic donors and those of healthy subjects throughout the day. 
 
A Langerhans Islet with insulin-producing cells (in green), and glucagon-producing cells (in red). Cell nuclei in blue. [UNIGE, Dibner Lab]
 
“The biological rhythms of the islet cells in type-2 diabetes exhibit both reduced amplitudes of circadian oscillations and poor synchronization capacity,” explains Dibner. “As a result, hormone secretion is no longer coordinated.”
 
“Moreover, the defects in temporal coordination of insulin and glucagon secretion observed in patients with type-2 diabetes were comparable to those measured in healthy islet cells with artificially-disrupted circadian clock," she adds.
 
Moreover, using a clock modulator molecule dubbed Nobiletin, extracted from lemon peel, the researchers succeeded in "repairing" the disrupted cellular clocks and partially restoring the islet cell function.
 
"By acting on one of the core-clock components, [Nobiletin] resets efficiently the amplitude of the oscillations in the human islets" says Dibner's colleague Dr Volodymyr Petrenko. "And as soon as we got the clocks back in sync, we also observed an improvement in insulin secretion."
 
The researchers will now continue to explore this repair mechanism in vivo, first in animal models. 
 
“Our society experiences epidemic growth in metabolic diseases, concomitant with shifted working and eating schedules, and lack of sleep,” says Dibner. “By re-synchronizing the perturbed molecular clocks, either by personalized eating and exercise schedules or with the help of clock modulator molecules, we hope to ultimately be able to provide an innovative solution to an epidemical metabolic problem affecting an ever-increasing proportion of the world's population."
 
Research is published in PNAS.
 
 
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