Mapping the human brain without distortions

To study the fine structure of the brain including its connections between neurons and the synapses, scientists generally use electron microscopes. However, the brain tissue must first be fixed to prepare it for this high magnification imaging method. This process causes the brain to shrink and as a result, microscope images can be distorted showing neurons to be much closer than they actually are.

Researchers now solved the problem by using a technique that rapidly freezes the brain, preserving its true structure. The innovative method called "cryofixation" to prevent brain shrinkage during the preparation for electron microscopy. The method uses jets of liquid nitrogen to "snap-freeze" brain tissue down to -90 degrees celsius within milliseconds. The brain tissue here was mouse cerebral cortex. "The high-pressure 'cryofixation' is a very attractive method for brain imaging.

Source: Graham Knott, Natalya Korogod and Carl Petersen,  Swiss Federal Institute of Technology in Lausanne

Hippocampus of brain stores the time and place of memories

For the first time, scientists have seen evidence of where the brain records the time and place of real-life memories. The left anterior of the hippocampus aren't the totality of the memories, but just the broad picture of where and when it occurred and also it helped to "fine-tune" the time and place. "What we're picking up here is not the whole memory, but the basic gist the where and when of the experience," said Per Sederberg, senior author of the study and assistant professor of psychology at Ohio State."This could be viewed as the memory hub, where we have these general, large-scale representations of our experiences."

Ref: Dylan M. Nielson, 2015, PNAS

DOI:10.1073/pnas.1507104112

FDA nod for lung cancer screening device with a low dose CT

Detection of small lung nodules are critical in identifying lung cancer at its earliest stages when it is the most treatable and curable. Low dose CT lung cancer screening will inevitably save lives through earlier diagnosis and treatment for patients.

Source: GE Healthcare, 2015

Sleep calculator

Scientists have discovered how an animal's biological clock wakes it up in the morning and puts it to sleep at night. Brain circadian neurons that govern the daily sleep-wake cycle's timing. High sodium channel activity in these neurons during the day turn the cells on and ultimately awaken an animal, and high potassium channel activity at night turn them off, allowing the animal to sleep.

Ref: Matthieu Flourakis et al., 2015, Cell.

The molecular mechanisms of brassinosteroids in plant breeding

Fig: Growth defects of the model research plant thale cress (Arabidopsis thaliana) which are induced by missing of steroid hormones (left side). With the help of gibberelline production the defects could be repaired (right side). Credit: Brigitte Poppenberger / TUM

Two growth-promoting groups of substances, or phytohormones, the gibberellins and the brassinosteroids are used independently of each other for the breeding and production of crop plants. It is discovered that without brassinosteroids, a plant is unable to produce gibberellins.

Reg: Unterholzner, 2015, Plant Cell.

DOI: 10.1105/tpc.15.00433​

'Bionic' spinach plants can detect explosives

By embedding spinach leaves with carbon nanotubes, MIT engineers have transformed spinach plants into sensors that can detect explosives and wirelessly relay that information to a handheld device similar to a smartphone.

Credit: Christine Daniloff/MIT

 

This is one of the first demonstrations of engineering electronic systems into plants, an approach that the researchers call "plant nanobionics." In this case,  Spinach plants were designed to detect chemical compounds known as nitroaromatics, which are often used in landmines and other explosives. When one of these chemicals is present in the groundwater sampled naturally by the plant, carbon nanotubes embedded in the plant leaves emit a fluorescent signal that can be read with an infrared camera. The camera can be attached to a small computer similar to a smartphone, which then sends an email to the user.

Ref: Min Hao Wong et al., (2016), Nitroaromatic detection and infrared communication from wild-type plants using plant nanobionics, Nature materials.

Full Text
DOI: 10.1038/nmat4771

Lab-grown lungs successfully transplanted into mice

Transplanted HLO-scaffold constructs engrafted, grew and possessed airway-like structures.

Keyword: HLOs-Human Lung Organoids, PLG- poly(lactide-co-glycolide)  

Fig: (A) PLG scaffold are 5 mm in diameter with honeycomb-patterned architecture. (B) The majority of Di-O labeled 1d HLOs (green) remained at the surface of the scaffold with a few organoids descending toward the middle of the scaffold. Inset shows aerial view of the scaffold with 1d HLOs (green) scattered throughout. (C) 1d HLOs settled within the pores of the scaffold. Scale bar represents 100 µm. (D) PLG scaffolds were seeded with 1d HLOs and cultured for 5 to 7 days in vitro in media supplemented with FGF10. The HLO-laden scaffolds were then transplanted into the mouse epididymal fat pad and harvested at 8 weeks. (E) HLO-scaffold (dotted line) was placed in mouse epididymal fat pad. (F) Transplanted HLOs (tHLOs) ranged from 0.5 cm to 1.5 cm in length. (G) The average number airway-like structures that were NKX2.1+ ECAD+ out of all ECAD+ structures was 86.19% +/- 4.14% (N = 10, error bars represent SEM). (H) H&E of tHLOs showed airway-like structures (right two panels, low and high mag) and pockets of cartilage (left panel). Scale bar at low mag represents 200 µm and high mag 100 µm. (I) Airway-like structures outlined by ECAD (white) expressed the lung marker NKX2.1 (green). Scale bar represents 50 µm. (J–K) Both the epithelium (β-CAT, red) and mesenchyme expressed the human nuclear marker, HUNU (J, green) and the human mitochondrial marker huMITO (K, green). Scale bars represent 50 µm in J–K and 10 µm in high mag image in K.

DOI: http://dx.doi.org/10.7554/eLife.19732.003

Researchers at the University of Michigan have transplanted lab-grown mini lungs into immunosuppressed mice where the structures were able to survive, grow and mature. Respiratory diseases account for nearly 1 in 5 deaths worldwide, and lung cancer survival rates remain poor despite numerous therapeutic advances during the past 30 years. Now, the researchers attempted to transplant the miniature lungs into mice, an approach that has been widely adopted in the stem cell field. 

Researchers characterized the transplanted mini lungs as well-developed tissue that possessed a highly organized epithelial layer lining the lungs.

One drawback was that the alveolar cell types did not grow in the transplants. Still, several specialized lung cell types were present, including mucus-producing cells, multiciliated cells and stem cells found in the adult lung.

Ref:: Briana R Dye et al., (2016) A bioengineered niche promotes in vivo engraftment and maturation of pluripotent stem cell derived human lung organoids, eLIFE.

Full Text (PDF) 
DOI: 10.7554/eLife.19732