Correction to: The biotechnological importance of the plant-specific NAC transcription factor family in crop improvement

Climate change, malnutrition, and food insecurity are the inevitable challenges being faced by the agriculture sector today. Plants are susceptible to extreme temperatures during the crucial phases of flowering and seed development, and elevated carbon levels also lead to yield losses. Productivity is also affected by floods and droughts. Therefore, increasing plant yield and stress tolerance are the priorities to be met through novel biotechnological interventions. The contributions of NAC genes towards enhancing plant survivability under stress is well known. Here we focus on the potential of NAC genes in the regulation of abiotic stress tolerance, secondary cell wall synthesis, lateral root development, yield potential, seed size and biomass, ROS signaling, leaf senescence, and programmed cell death. Once naturally tolerant candidate NAC genes have been identified, and the nature of their association with growth and fitness against multi-environmental stresses has been determined, they can be exploited for building inherent tolerance in future crops via transgenic technologies. An update on the latest developments is provided in this review, which summarizes the current understanding of the roles of NAC in the establishment of various stress-adaptive mechanisms in model and food crop plants.

     

Protein-facilitated gold nanoparticle formation as indicators of ionizing radiation

The use of X-ray radiation in radiotherapy is a common treatment for many cancers. Despite several scientific advances, determination of radiation delivered to the patient remains a challenge due to the inherent limitations of existing dosimeters including fabrication and operation. Here, we describe a colorimetric nanosensor that exhibits unique changes in color as a function of therapeutically relevant radiation dose (3–15 Gy). The nanosensor is formulated using a gold salt and maltose-binding protein as a templating agent, which upon exposure to ionizing radiation is converted to gold nanoparticles. The formation of gold nanoparticles from colorless precursor salts renders a change in color that can be observed visually. The dose-dependent multicolored response was quantified through a simple ultraviolet–visible spectrophotometer and the peak shift associated with the different colored dispersions was used as a quantitative indicator of therapeutically relevant radiation doses. The ease of fabrication, visual color changes upon exposure to ionizing radiation, and quantitative read-out demonstrates the potential of protein-facilitated biomineralization approaches to promote the development of next-generation detectors for ionizing radiation.     

Chemical biology: Paper alert

A selection of interesting papers that were published in the two months before our press date in major journals most likely to report significant results in chemical biology.     

Episodic salinization and freshwater salinization syndrome mobilize base cations,carbon, and nutrients to streams across urban regions

Urbanized watersheds in colder climates experience episodic salinization due to anthropogenic salt inputs and runoff from impervious surfaces. Episodic salinization can be manifested as a ‘pulse’ in concentrations and fluxes of salt ions lasting from hours to days after snowstorms in response to road salting. Episodic salinization contributes to freshwater salinization syndrome, characterized by cascading mobilization of chemicals and shifting acid–base status. We conducted laboratory experiments and analyzed high-frequency sensor data to investigate the water quality impacts of freshwater salinization syndrome and episodic salinization across 12 watersheds draining two major metropolitan regions along the U.S. East Coast. Sediments from 12 watersheds spanning land use gradients across two metropolitan regions, Baltimore, Maryland and Washington DC, were incubated across a range of replicated salinity treatments (0–10 g/L sodium chloride). There were statistically significant linear increasing trends in calcium and potassium concentrations with experimental salinization across all 12 sites and in magnesium concentrations at 11 of 12 sites (p?<?0.05), with mean rates of increase of 1.92?±?0.31 mg-Ca per g-NaCl, 2.80?±?0.67 mg–K per g-NaCl, and 1.11?±?0.19 mg-Mg per g-NaCl, respectively. Similarly, there were statistically significant increasing linear trends in total dissolved nitrogen (TDN) concentrations with experimental salinization at 9 of the 12 sites, with a mean rate of increase of 0.07?±?0.01 mg-N per g-NaCl. There were statistically significant increasing linear trends in soluble reactive phosphorus (SRP) concentrations with experimental salinization at 7 of the 12 sites (p?<?0.05), with a mean rate of increase of 2.34?±?0.66 µg-P per g-NaCl. The response of dissolved inorganic carbon (DIC) and organic carbon (DOC) concentrations to experimental salinization varied between sites, and dissolved silica did not show any significant response. High-frequency sensors near the experimental sites showed statistically significant positive linear relationships between nitrate concentrations, specific conductance, and chloride concentrations similar to relationships observed in laboratory incubations. Our results suggested that episodic salinization and freshwater salinization syndrome can mobilize base cations and nutrients to streams through accelerated ion exchange and stimulate different biogeochemical processes by shifting pH ranges and ionic strength. The growing impacts of freshwater salinization syndrome and episodic salinization on nutrient mobilization, shifting acid–base status, and augmenting eutrophication warrant serious consideration in water quality management.     

A critical review on brain and heart axis response in COVID-19 patients: Molecular mechanisms,mediators, biomarkers,and therapeutics

Since the outbreak of highly virulent coronaviruses, significant interest was assessed to the brain and heart axis (BHA) in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-affected patients. The majority of clinical reports accounted for unusual symptoms associated with SARS-CoV-2 infections which are of the neurological type, such as headache, nausea, dysgeusia, anosmia, and cerebral infarction. The SARS-CoV-2 enters the cells through the angiotensin-converting enzyme (ACE-2) receptor. Patients with prior cardiovascular disease (CVD) have a higher risk of COVID-19 infection and it has related to various cardiovascular (CV) complications. Infected patients with pre-existing CVDs are also particularly exposed to critical health outcomes. Overall, COVID-19 affected patients admitted to intensive care units (ICU) and exposed to stressful environmental constraints, featured with a cluster of neurological and CV complications. In this review, we summarized the main contributions in the literature on how SARS-CoV-2 could interfere with the BHA and its role in affecting multiorgan disorders. Specifically, the central nervous system involvement, mainly in relation to CV alterations in COVID-19-affected patients, is considered. This review also emphasizes the biomarkers and therapy options for COVID-19 patients presenting with CV problems.     

Prompt Protein Glycosylation during Acute Heat Stress

Constitutive patterns of protein synthesis and protein glycosylation are severely disrupted by acute heat stress. Stressed cells respond by preferential synthesis of specific proteins, e.g., the well-known family of heat shock proteins. We observed another response that rapidly occurs during heating periods as short as 10 min at 45°C. During that period, CHO cells began to glycosylate specific proteins, designated as "prompt" stress glycoproteins (P-SG), while constitutive protein glycosylation ceased. Labeling of P-SGs showed a dose response with time and with temperature and appeared regardless of the label used (D-[³H]mannose or D-[³H]-glucose). On SDS-PAGE, the major P-SG was characterized by M_r ≈ 67 kDa (P-SG67) and pI = 5.1. Other less prominent P-SGs appeared at M_r 160, 100, 64, 60, and 47 kDa; incorporated label showed little turnover during 24 h at 37°C. Prompt glycosylation was inhibited by tunicamycin, and label incorporated into P-SGs was sensitive to N -glycosidase F, but not to O-glycosidase. Analysis of enzymatically digested P-SG67 indicated that label had been incorporated into both high-mannose (Man₉G1cNAc) and complex-type oligosaccharides. Brefeldin A did not eliminate P-SG67 labeling, but caused the further appearance of novel, Brefeldin-associated P-SGs. Labeling of P-SG67 oligosaccharides occurred without significant concomitant protein synthesis, suggesting that addition of labeled oligosaccharides largely occurred on mature, rather than nascent proteins. The functional significance of prompt glycosylation remains to be defined, but we propose that this novel phenomenon is an integral part of the cellular heat stress response.     

Nutrient modulation based process engineering strategy for improved butanol production from Clostridium acetobutylicum

The present study demonstrates a process engineering strategy to achieve high butanol titer and productivity from wild type Clostridium acetobutylicum MTCC 11274. In the first step, two different media were optimized with the objectives of maximizing the biomass and butanol productivity, respectively. In the next step, attributes of these two media compositions were integrated to design a two-stage fed-batch process which resulted in maximal butanol productivity of 0.55 g L⁻¹ h⁻¹ with titer of 13.1 g L⁻¹. Further, two-stage fed-batch process along with combinatorial use of magnesium limitation and calcium supplementation resulted in the highest butanol titer and productivity of 16.5 g L⁻¹ and 0.59 g L⁻¹ h⁻¹, respectively. Finally, integration of the process with gas stripping and modulation of feeding duration resulted in a cumulative butanol titer of 54.3 g L⁻¹ and productivity of 0.58 g L⁻¹ h⁻¹. The strategy opens up possibility of developing a viable butanol bioprocess. © 2019 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2771, 2019.     

Biokinetics of lead in various organs of rats using radiotracer technique

Uptake, distribution, and elimination of lead in various organs of rats have been studied using a radiotracer technique. The elimination data for various organs, except whole blood, is fitted to a double-exponential function using a computer program. The biological half-lives along with the percent elimination of lead by two different decay modes in testis, epididymis, prostate, and seminal vesicles are being reported together with that in liver, kidney, blood, and whole body. It is evident from this study that the elimination of lead is limited for all the organs and permits lead accumulation in the bone, where it is stored and becomes almost unavailable for elimination. Lead levels in blood, testis, and femur of lead acetate-fed rats measured using atomic absorption spectroscopy have been correlated to the uptake of²¹⁰Pb in various organs.