Images of the week

Brassicaceae Family: A Rich Mine of Bioactive Phytochemicals

Plant Sciences ; Created: 25 Mar 2020; Latest updated: 05 Apr 2020

Brassicaceae family vegetables have an ample worldwide distribution, which can be found in all continents except Antarctica. One of the most striking features of this botanical family is the presence of several kinds of secondary metabolites with a distinctive taste, and also interesting bioactivities. The most deeply studied are the glucosinolates (GSL) and from their bioactive breakdown products, the isothiocyanates and the indoles. Moreover, these species are also rich and possess unique profiles of phenolic compounds, carotenoids, and other groups of less studied compounds such as phytoalexins, terpenes, phytosteroids, and tocopherols, here reviewed.

Novel genetically encoded bright positive calcium indicator NCaMP7

Molecular Biology ; Created: 17 Mar 2020; Latest updated: 05 Apr 2020

Green fluorescent genetically encoded calcium indicators (GECIs) are the most popular
tool for visualization of calcium dynamics in vivo. However, most of them are based on the
EGFP protein and have similar molecular brightnesses. The NTnC indicator, which is composed
of the mNeonGreen fluorescent protein with the insertion of troponin C, has higher brightness
as compared to EGFP-based GECIs, but shows a limited inverted response with an ΔF/F of 1.
By insertion of a calmodulin/M13-peptide pair into the mNeonGreen protein, we developed a green
GECI called NCaMP7. In vitro, NCaMP7 showed positive response with an ΔF/F of 27 and high
affinity (Kd of 125 nM) to calcium ions. NCaMP7 demonstrated a 1.7-fold higher brightness and
similar calcium-association/dissociation dynamics compared to the standard GCaMP6s GECI in vitro.
According to fluorescence recovery after photobleaching (FRAP) experiments, the NCaMP7 design
partially prevented interactions of NCaMP7 with the intracellular environment. The NCaMP7 crystal
structure was obtained at 1.75Å resolution to uncover the molecular basis of its calcium ions sensitivity.
The NCaMP7 indicator retained a high and fast response when expressed in cultured HeLa and
neuronal cells. Finally, we successfully utilized the NCaMP7 indicator for in vivo visualization of
grating-evoked and place-dependent neuronal activity in the visual cortex and the hippocampus of
mice using a two-photon microscope and an NVista miniscope, respectively.

Potential Factors Influencing Repeated SARS Outbreaks in China

Pathology & Pathobiology ; Created: 11 Mar 2020; Latest updated: 05 Apr 2020

Within last 17 years two widespread epidemics of severe acute respiratory syndrome (SARS) occurred in China, which were caused by related coronaviruses (CoVs): SARS-CoV and SARS-CoV-2. Although the origin(s) of these viruses are still unknown and their occurrences in nature are mysterious, some general patterns of their pathogenesis and epidemics are noticeable. Both viruses utilize the same receptor—angiotensin-converting enzyme 2 (ACE2)—for invading human bodies. Both epidemics occurred in cold dry winter seasons celebrated with major holidays, and started in regions where dietary consumption of wildlife is a fashion. Thus, if bats were the natural hosts of SARS-CoVs, cold temperature and low humidity in these times might provide conducive environmental conditions for prolonged viral survival in these regions concentrated with bats. The widespread existence of these bat-carried or -released viruses might have an easier time in breaking through human defenses when harsh winter makes human bodies more vulnerable. Once succeeding in making some initial human infections, spreading of the disease was made convenient with increased social gathering and holiday travel. These natural and social factors influenced the general progression and trajectory of the SARS epidemiology. However, some unique factors might also contribute to the origination of SARS in Wuhan. These factors are discussed in different scenarios in order to promote more research for achieving final validation.

Dislocation Density during Thermomechanical Treatment of Microalloyed Niobium Steel

Metallurgy ; Created: 04 Mar 2020; Latest updated: 05 Apr 2020

In this paper, thermomechanical processing of niobium microalloyed steel was performed
with the purpose of determining the interaction between niobium precipitates and dislocations, as well
as determining the influence of the temperature of final deformation on the degree of precipitation
and dislocation density. Two variants of thermomechanical processing with di erent final rolling
temperatures were carried out. Samples were studied using electrochemical isolation with an atomic
absorption spectrometer, transmission electron microscopy, X-ray di raction analysis, and universal
tensile testing with a thermographic camera. The results show that the increase in the density of
dislocations before the onset of intense precipitation is insignificant because the recrystallization
process takes place simultaneously. It increases with the onset of strain-induced precipitation. In this
paper, it is shown that niobium precipitates determine the density of dislocations. The appearance
of Lüders bands was noticed as a consequence of the interaction between niobium precipitates and
dislocations during the subsequent cold deformation. In both variants of the industrial process
performed on the cold deformed strip, Lüders bands appeared.

Bioprospection of Cold-Tolerant Microbes

Microbiology ; Created: 22 Feb 2020; Latest updated: 05 Apr 2020

Cold adapted microorganisms represent a large fraction of biomass on earth due to the dominance of low temperature environments. Himalaya is one of the most important low temperature environments on Earth because it possess environmental similarities to Polar Regions. The extreme cold environments of Himalaya are mainly dependent on the tiny life forms because of climatic restrictions to higher plants and animals. These cold loving microbes are known to possess several structural and functional adaptations in order to perform various life processes under the stressful low temperature environments. Their biological activities maintain the nutrient flux in environment and contribute in the global biogeochemical cycles. The culture dependent and culture independent studies revealed their diversity in community structure and functional potential. Apart from the ecological importance, these microorganisms have been recognized as a source of cold active enzymes and novel bioactive compounds. These products have several applications in biotechnological industries.