Observation of coherent delocalized phonon-like modes in DNA under physiological conditions

Underdamped terahertz-frequency delocalized phonon-like modes have long been suggested to play a role in the biological function of DNA. Such phonon modes involve the collective motion of many atoms and are prerequisite to understanding the molecular nature of macroscopic conformational changes and related biochemical phenomena. Initial predictions were based on simple theoretical models of DNA. However, such models do not take into account strong interactions with the surrounding water, which is likely to cause phonon modes to be heavily damped and localized. Here we apply state-of-the-art femtosecond optical Kerr effect spectroscopy, which is currently the only technique capable of taking low-frequency (GHz to THz) vibrational spectra in solution. We are able to demonstrate that phonon modes involving the hydrogen bond network between the strands exist in DNA at physiologically relevant conditions. In addition, the dynamics of the solvating water molecules is slowed down by about a factor of 20 compared with the bulk

Visual processing of pictorial and facial images in human and monkey

Over the last two decades, the study of 'repetition effects' in behavioural and Event Related Potential (E.R.P) research has originated and added to theories of memory organisation. In this series of experiments, behavioural and E.R.P correlates of human and monkey visual memory were investigated, using the repetition effect as the main index of processing, and manipulating the semantic content of the experimental stimuli. The research has a large founding in established results from lexical studies. The use of pictorial material in this series of experiments extends these results to more general visual memory functions. E.R.P recordings were taken from two monkeys trained extensively to perform a matching-to-sample picture recognition task. The waveforms generated by novel instances of highly familiar pictures were compared to those elicited by repeats. In a further study with unfamiliar pictures the repetition of items had an effect on the evoked potentials for only one of the two subjects. Two further studies were made with one monkey viewing unfamiliar and familiar face pictures. In both these studies, an early potential emerged which was more positive in response to faces than to objects. In order to investigate the importance of the semantic content of stimulus items for memory processes, human E.R.Ps generated by novel and repeated presentations of 'meaningful' and 'meaningless' pictorial images were recorded. Repetition of the meaningful (but not meaningless) pictures attenuated the N400 component associated with the first presentation of a stimulus

Transport of Agrichemicals by Wind Eroded Sediments to Nontarget Areas

Water and wind erosion are the primary mechanisms by which surface soil is removed from agricultural fields. Wind erosion accounts for as much or more soil loss (tons/acre/year) than does water erosion. Sediments moved by wind may carry agrichemicals from agricultural fields to nontarget areas. Nontarget areas may include road ditches, shelterbelts, and waterways. The objective of this study was to determine if agrichemical movement via wind blown sediment is a potential pollutant of surface and/or groundwater. Samples of sediment that had been deposited in ditches on top of snow were collected during winters of 1994 and 1995 near or around Brookings, SD. Soil samples from adjacent fields (top 1 inch) were also collected. Soil and sediment samples were extracted and alachlor, atrazine, and atrazine metabolites, desethylatrazine and desisopropylatrazine were quantified. Alachlor was detected in about 30% of soil and sediment samples in both years with an average concentration of 2.2 ppb in soil and 5.44 ppb in sediment in 1995. In 1994, atrazine, desethylatrazine, and desisopropylatrazine were detected in 70%, 100%, and 50% of the sediment samples and 70%, 90%, and 60% of the soil samples, respectively. In 1995, atrazine, desethylatrazine, and desisopropylatrazine were detected in 73%, 27%, and 9% of the sediment samples at average concentrations of 8.9, 0.89, and 56.4 ppb, respectively. Atrazine, desethylatrazine, and desisopropylatrazine were detected in 70%, 40%, and 10% of the soil samples in 1995 at average concentrations of 11.9, 2.0, and 0.9 ppb, respectively. Herbicides were detected in most of the sediment samples. This suggests that wind erosion may be a transport mechanism by which herbicides are deposited into nontarget areas

The effects of weather on fungal abundance and richness among 25 communities in the Intermountain West

BACKGROUND: Because moisture and temperature influence the growth of fungi, characterizing weather conditions favorable for fungi may be used to predict the abundance and richness of fungi in habitats with different climate conditions. To estimate habitat favorability to fungi, we examined the relationship of fungal abundance and species richness to various weather and environmental parameters in the Intermountain West. We cultured fungi from air and leaf surfaces, and collected continuous temperature and relative humidity measures over the growing season at 25 sites. RESULTS: Fungal richness was positively correlated with fungal abundance (r = 0.75). Measures of moisture availability, such as relative humidity and vapor pressure deficit, explained more of the variance in fungal abundance and richness than did temperature. Climate measurements from nearby weather stations were good predictors of fungal abundance and richness but not as good as weather measurements obtained in the field. Weather variables that took into account the proportion of time habitats experienced favorable or unfavorable relative humidity and temperatures were the best predictors, explaining up to 56% of the variation in fungal abundance and 72% for fungal richness. CONCLUSION: Our results suggest that the abundance and richness of fungi in a habitat is limited by the duration of unfavorable weather conditions. Because fungal pathogens likely have similar abiotic requirements for growth as other fungi, characterizing weather conditions favorable for fungi also may be used to predict the selective pressures imposed by pathogenic fungi on plants in different habitats

Wnt5a induces ROR1 to recruit cortactin to promote breast-cancer migration and metastasis.

ROR1 is a conserved oncoembryonic surface protein expressed in breast cancer. Here we report that ROR1 associates with cortactin in primary breast-cancer cells or in MCF7 transfected to express ROR1. Wnt5a also induced ROR1-dependent tyrosine phosphorylation of cortactin (Y421), which recruited ARHGEF1 to activate RhoA and promote breast-cancer-cell migration; such effects could be inhibited by cirmtuzumab, a humanized mAb specific for ROR1. Furthermore, treatment of mice bearing breast-cancer xenograft with cirmtuzumab inhibited cortactin phosphorylation in vivo and impaired metastatic development. We established that the proline at 841 of ROR1 was required for it to recruit cortactin and ARHGEF1, activate RhoA, and enhance breast-cancer-cell migration in vitro or development of metastases in vivo. Collectively, these studies demonstrate that the interaction of ROR1 with cortactin plays an important role in breast-cancer-cell migration and metastasis

Parallel waves of inductive signaling and mesenchyme maturation regulate differentiation of the chick mesonephros

AbstractThe mesonephros is a linear kidney that, in chicken embryos, stretches between the axial levels of the 15th to the 30th somites. Mesonephros differentiation proceeds from anterior to posterior and is dependent on signals from the nephric duct, which migrates from anterior to posterior through the mesonephric region. If migration of the nephric duct is blocked, markers of tubule differentiation, including Lhx1 and Wnt4, are not activated posterior to the blockade. However, activation and maintenance of the early mesonephric mesenchyme markers Osr1, Eya1 and Pax2 proceeds normally in an anterior-to-posterior wave, indicating that these genes are not dependent on inductive signals from the duct. The expression of Lhx1 and Wnt4 can be rescued in duct-blocked embryos by supplying a source of canonical Wnt signaling, although epithelial structures are not obtained, suggesting that the duct may express other tubule-inducing signals in addition to Wnts. In the absence of the nephric duct, anterior mesonephric mesenchyme adjacent to somites exhibits greater competence to initiate tubular differentiation in response to Wnt signaling than more posterior mesonephric mesenchyme adjacent to unsegmented paraxial mesoderm. It is proposed that mesonephric tubule differentiation is regulated by two independent parallel waves, one of inductive signaling from the nephric duct and the other of competence of the mesonephric mesenchyme to undergo tubular differentiation, both of which travel from anterior to posterior in parallel with the formation of new somites

STATE-OF-THE-ART NANOTECHNOLOGY BASED DRUG DELIVERY STRATEGIES TO COMBAT COVID-19

The emerging Coronavirus Disease-19 (COVID-19) pandemic has had a global impact on all important aspects of our society. As it is known, SARS-Cov-2 can withstand up to 72 h in adverse environmental conditions, which can aid its rapid spread. Woefully, an efficacious and approbated vaccine for the SARS-CoV-2 virus remains unavailable, which makes the problem more frightening and presently more complicated bestowing forlorn medical care. Nevertheless, global clinical research is studying several over-the-counter (OTC) drugs approved for other indications to confront coronavirus. Over the past decade, therapeutic nanoparticles have been regarded as a felicitous tool for the efficient and persnickety delivery of therapeutic groups (i.e., drugs, vaccines, siRNAs, and peptides) to the site of infection. They can adequately convey the drug encapsulated nanoparticle to a designated locus without instigating unsought effects. Besides, they acquiesce the use of non-invasive imaging methods to monitor the surface of the infection and the response to treatment. The formulated nanoparticle is apposite for intranasal drug delivery which is a meritorious method to deliver therapeutic moiety for viral diseases affecting the lungs. Applying nanoparticles via intranasal route surmounted several demerits of mucosal administration like circumventing enzymatic degradation of the therapeutic moiety, upgrading and prolonging the action of the drug, etc., and can thus corroborate as an exceptional strategy to encounter respiratory viruses like coronavirus. In this article, we illuminate the promising role of nanoparticles as effective carriers of therapeutic or immunomodulatory agents to help combat COVID-19. The search criteria used were Pubmed, Medscape, Google scholar, etc and the keywords are coronavirus, nanoformulations, nanoparticles, drug delivery, intranasal delivery, etc. The articles range from 2012 to 2020

Oxidative Stress in Oocytes during Midprophase Induces Premature Loss of Cohesion and Chromosome Segregation Errors

In humans, errors in meiotic chromosome segregation that produce aneuploid gametes increase dramatically as women age, a phenomenon termed the maternal age effect. During meiosis, cohesion between sister chromatids keeps recombinant homologs physically attached and premature loss of cohesion can lead to missegregation of homologs during meiosis I. A growing body of evidence suggests that meiotic cohesion deteriorates as oocytes age and contributes to the maternal age effect. One hallmark of aging cells is an increase in oxidative damage caused by reactive oxygen species (ROS). Therefore, increased oxidative damage in older oocytes may be one of the factors that leads to premature loss of cohesion and segregation errors. To test this hypothesis, we used an RNAi strategy to induce oxidative stress in Drosophila oocytes and measured the fidelity of chromosome segregation during meiosis. Knockdown of either the cytoplasmic or mitochondrial ROS scavenger superoxide dismutase (SOD) caused a significant increase in segregation errors, and heterozygosity for an smc1 deletion enhanced this phenotype. FISH analysis indicated that SOD knockdown moderately increased the percentage of oocytes with arm cohesion defects. Consistent with premature loss of arm cohesion and destabilization of chiasmata, the frequency at which recombinant homologs missegregate during meiosis I is significantly greater in SOD knockdown oocytes than in controls. Together these results provide an in vivo demonstration that oxidative stress during meiotic prophase induces chromosome segregation errors and support the model that accelerated loss of cohesion in aging human oocytes is caused, at least in part, by oxidative damage