A Requirement for Polyamines during the Cell Division Phase of Radicle Emergence in Seeds of Acer saccharum

When stratified sugar maple seeds were germinated at 5C, celldivision did not contribute to radicle emergence or to earlygrowth of the embryonic axis. Putrescine, spermidine and sperminecontents remained low throughout stratification, but followinggermination their levels rose gradually for several days andthen entered a phase of rapid accumulation concurrent with initiationof rapid cell division. When inhibitors of putrescine and polyaminebiosynthesis were applied to newly germinated seeds, levelsof the amines and cell division were markedly reduced, but cellelongation, as evidenced by growth of hypocotyls, was not affected. ¹ Present address: Department of Chemistry and Biochemistry,University of Guelph, Guelph, Ontario, Canada N1G 2W1.     

Toxin-Induced Necroptosis Is a Major Mechanism of Staphylococcus aureus Lung Damage

Staphylococcus aureus USA300 strains cause a highly inflammatory necrotizing pneumonia. The virulence of this strain has been attributed to its expression of multiple toxins that have diverse targets including ADAM10, NLRP3 and CD11b. We demonstrate that induction of necroptosis through RIP1/RIP3/MLKL signaling is a major consequence of S. aureus toxin production. Cytotoxicity could be prevented by inhibiting either RIP1 or MLKL signaling and S. aureus mutants lacking agr, hla or Hla pore formation, lukAB or psms were deficient in inducing cell death in human and murine immune cells. Toxin-associated pore formation was essential, as cell death was blocked by exogenous K+ or dextran. MLKL inhibition also blocked caspase-1 and IL-1β production, suggesting a link to the inflammasome. Rip3 ^-/- mice exhibited significantly improved staphylococcal clearance and retained an alveolar macrophage population with CD200R and CD206 markers in the setting of acute infection, suggesting increased susceptibility of these leukocytes to necroptosis. The importance of this anti-inflammatory signaling was indicated by the correlation between improved outcome and significantly decreased expression of KC, IL-6, TNF, IL-1α and IL-1β in infected mice. These findings indicate that toxin-induced necroptosis is a major cause of lung pathology in S. aureus pneumonia and suggest the possibility of targeting components of this signaling pathway as a therapeutic strategy.     

Cystic fibrosis: A look into the future of prenatal screening and therapy

Despite recent guidelines suggesting prenatal screening for carriers of cystic fibrosis (CF) mutations, many physicians do not offer patients this service or even counseling. Some argue that the risks of miscarriage associated with prenatal diagnostic techniques outweigh the benefit of added insight, but with the advent of newer, noninvasive techniques, risks of miscarriage may be significantly lowered. Prenatal diagnosis provides parents the time to prepare for raising a child with CF, and soon, could provide treatment options in utero that could improve quality of life. Here, we describe two of the most promising gene therapy approaches: lentivirus and adenoassociated virus (AAV)‐mediated gene transduction. Thus, prenatal detection and treatment is in a most crucial stage for care of patients with CF. Birth Defects Research (Part C) 105:73–80, 2015. © 2015 Wiley Periodicals, Inc.     

Global and national trends,gaps, and opportunities in documenting and monitoring species distributions

Conserving and managing biodiversity in the face of ongoing global change requires sufficient evidence to assess status and trends of species distributions. Here, we propose novel indicators of biodiversity data coverage and sampling effectiveness and analyze national trajectories in closing spatiotemporal knowledge gaps for terrestrial vertebrates (1950 to 2019). Despite a rapid rise in data coverage, particularly in the last 2 decades, strong geographic and taxonomic biases persist. For some taxa and regions, a tremendous growth in records failed to directly translate into newfound knowledge due to a sharp decline in sampling effectiveness. However, we found that a nation’s coverage was stronger for species for which it holds greater stewardship. As countries under the post-2020 Global Biodiversity Framework renew their commitments to an improved, rigorous biodiversity knowledge base, our findings highlight opportunities for international collaboration to close critical information gaps.

Conserving and managing biodiversity in the face of ongoing global change requires sufficient evidence to assess status and trends of species distributions. This study analyzes national trajectories in closing spatiotemporal knowledge gaps for terrestrial vertebrates (1950-2019) based on novel indicators of data coverage and sampling effectiveness.     

Application of LIBS in Detection of Antihyperglycemic Trace Elements in Momordica charantia

The present study exploits the information based on concentration of trace elements and minerals in understanding the role/mechanism of action of freeze-dried fruit powder suspended in distilled water of Momordica charantia (family: Cucurbitaceae) in diabetes treatment. Laser-induced break down spectroscopy (LIBS) spectra of plant product was recorded under optimized experimental conditions and analyzed. Several atomic lines such as Na, K, Mg, Ca, Fe, Al, etc. have been observed in the LIBS spectra of the above plant product. The concentrations of these minerals are determined by using calibration-free LIBS method. Correlation between the concentration of these elements/minerals and their defined role in diabetes management was studied in normal as well as diabetic animal models.     

A flow cytometric assay for screening improved heterologous protein secretion in yeast

Selection of highly productive hosts for protein expression is a significant component of bioprocess design. As an alternative to traditional plate, halo, and suppression-based screens, we describe a high-throughput, flow cytometric assay, the Cell Surface Secretion Assay (CeSSA), that can be used to select for improved heterologous protein secretion from a population of S. cerevisiae mutants. A ligand is covalently attached to the cell surface via a PEG linker, and as cells secrete a protein that binds the tethered ligand, the protein is captured on the surface where it can be labeled and the cells sorted using flow cytometry. This report describes three different protein/ligand interactions that have been demonstrated with this system. Single-pass sorting enrichments from 23- to 54-fold have been validated in the separation of a 3-fold higher secretor from a background population of wild-type secretors making this system applicable to large library screening (10(8) clones). A mathematical model was developed to improve the parameters of the assay further. The model was validated with time course data and predicts an optimal screening window. The model also predicts a 60-fold enrichment rate for the validation experiment described above. With the development of this selection system, limitations presented by traditional, particularly plate-based, secretion assays can be overcome so that a larger search space can be examined under conditions closer to the growth physiology experienced by cells in fermentors.     

Sensing the Heat of Tomato Products Red: The New Approach to the Objective Assessment of their Color

The concept of optothermal window (OW) detection was used for the first time to assess the color of several products (juice, purée, paste) derived from thermally processed tomatoes. Unlike traditional techniques that operate either in the reflectance or transmission mode, the method proposed here actually relies on indirect measurement of absorbance in optically opaque and scattering samples. Very good correlation between the magnitude of the OW signal and the color-related parameters [colorimetric index L* and tomato paste index (TPI)] was observed.     

Stochastic kinetics of intracellular huntingtin aggregate formation

Neurodegeneration in Huntington disease is described by neuronal loss in which the probability of cell death remains constant with time. However, the quantitative connection between the kinetics of cell death and the molecular mechanism initiating neurodegeneration remains unclear. One hypothesis is that nucleation of protein aggregates containing exon I fragments of the mutant huntingtin protein (mhttex1), which contains an expanded polyglutamine region in patients with the disease, is the explanation for the infrequent but steady occurrence of neuronal death, resulting in adult onset of the disease. Recent in vitro evidence suggests that sufficiently long polyglutamine peptides undergo a unimolecular conformational change to form a nucleus that seeds aggregation. Here we use this nucleation mechanism as the basis to derive a stochastic mathematical model describing the probability of aggregate formation in cells as a function of time and mhttex1 protein concentration, and validate the model experimentally. These findings suggest that therapeutic strategies for Huntington disease predicated on reducing the rate of mhttex1 aggregation need only make modest reductions in huntingtin expression level to substantially increase the delay time until aggregate formation.     

Alveolar diffusion-perfusion interactions during high-altitude residence in guinea pigs.

We previously reported in weanling guinea pigs raised at high altitude (HA; 3,800 m) an elevated lung diffusing capacity estimated by morphometry from alveolar-capillary surface area, harmonic mean blood-gas barrier thickness, and pulmonary capillary blood volume (Vc) compared with litter-matched control animals raised at an intermediate altitude (IA; 1,200 m) (Hsia CCW, Polo Carbayo JJ, Yan X, Bellotto DJ. Respir Physiol Neurobiol 147: 105-115, 2005). To determine if HA-induced alveolar ultrastructural changes are associated with improved alveolar function, we measured lung diffusing capacity for carbon monoxide (DLCO), membrane diffusing capacity for carbon monoxide (DMCO), Vc, pulmonary blood flow, and lung volume by a rebreathing technique in litter-matched male weanling Hartley guinea pigs raised at HA or IA for 4 or 12 mo. Separate control animals were also raised and studied at sea level (SL). Resting measurements were obtained in the conscious nonsedated state. In HA animals compared with corresponding IA or SL controls, lung volume and hematocrit were significantly higher while pulmonary blood flow was lower. At a given pulmonary blood flow, DLCO and DMCO were higher in HA-raised animals than in control animals without a significant change in Vc. We conclude that 1) HA residence enhanced physiological diffusing capacity corresponding to that previously estimated on the basis of structural adaptation, 2) adaptation in diffusing capacity and its components should be interpreted with respect to pulmonary blood flow, and 3) this noninvasive rebreathing technique could be used to follow adaptive responses in small animals.     

Cardiovascular regulation during hypoxia in embryos of the domestic chicken Gallus gallus

Renewed interest in the use of the embryonic chicken as a model of perinatal cardiovascular regulation has inspired new questions about the control mechanisms that respond to acute perturbations, such as hypoxia. The objectives of this study were to determine the cardiovascular responses, the regulatory mechanisms involved in those cardiovascular responses, and whether those mechanisms involved the central nervous system (CNS) of embryonic chickens. Heart rate (f(H)) and blood pressure were measured in chicken embryos of different incubation ages during exposure to different levels of hypoxia (15, 10, and 5% O(2)). At all levels of hypoxia and at all developmental ages, a depression of f(H) and arterial pressure was observed, with the exception of day 20 embryos in 15 and 10% O(2). The intensity of the embryonic f(H) and blood pressure responses were directly related to the level of hypoxia used. Muscarinic and alpha-adrenergic receptor stimulation limited the hypoxic hypotension on days 15-19 and 15-21, respectively, as indicated after blockade with atropine and phentolamine. During the final 3 days of incubation, the intensity of the hypoxic hypotension was magnified due to alpha-vasodilation caused by beta-adrenergic and muscarinic receptor stimulation. In 19- to 21-day-old embryos, the f(H) response to hypoxia was limited by alpha-adrenergic receptor stimulation as indicated by the accentuated bradycardia after blockade with phentolamine. Furthermore, on day 21, atropine limited the hypoxic bradycardia, indicating that muscarinic receptors also play a role in the f(H) response at this age. In addition, the muscarinic actions on the heart and the adrenergic effects on the vasculature appeared to occur through a hypoxic-induced direct release from chromaffin tissue and autonomic nerve terminals. Thus, in embryonic chickens, the only cardiovascular response to hypoxia that involves the CNS was the cholinergic regulation of arterial pressure after day 15 of incubation. Therefore, although embryonic chickens and fetal sheep, the standard models of perinatal cardiovascular physiology, respond to hypoxia with a similar redistribution of cardiac output, the underlying mechanisms differ between these species.