Effects of prostaglandins E2 and F2α on lecithin biosynthesis by cultured lung cells

Transformed cells from human lung carcinoma (Line A549), resembling type II pneumocytes, were cultured in monolayer at 37°C and incubated for five hours with ³H-choline and ¹⁴C-palmitate in the presence of various concentrations of prostaglandins (PGs) E₂ and F_2α. In the control (no PG) the level of % palmitate incorporation was 13.5 × as high as that of choline, after taking isotope dilution into account. Between the concentrations studied, 0.1 and 10 μM, both prostaglandins stimulated markedly the incorporation of both precursors, though choline up to 3 × better than palmitate. This was indicated by a change in the palmitate/choline incorporation ratio from 13.5 to as low as 4.2. At the lowest PG concentration, 0.1 μM, PGE₂ was much more effective than PGF_2α in stimulating the incorporation of both precursors.     

Negative-Staining of Protozoa with Nigrosin

The use of nigrosin in a rapid but accurate method for the demonstration of cilia bands, vacuoles and cytoplasmic inclusions in infusorians is discussed. The general effects of the dye as well as its staining action are presented together with a brief explanation of the physics of the action. The technic proposed involves mixing a drop of infusion on the slide with a drop of 10% aqueous nigrosin; excess stain is drained off, the specimen dried and mounted.     

Glutamic acid modification of vincristine toxicity

The principal limiting feature of the antitumor agent, vincristine, in the clinic has been neurotoxicity; there are no known agents which can routinely prevent or decrease this side effect. Glutamic acid in laboratory and clinical investigations in the early 1960s was found to antagonize vinblastine, another clinically useful vinca alkaloid. Glutamic acid 250 mg/kg/d i.p. was given to normal mice treated with repetitive doses of vincristine 1.5 mg/kg every other day. When glutamic acid was given both before and during vincristine administration, it produced a 49-79% increase in survival compared to control mice receiving vincristine only (p less than 0.01). Other schedules of glutamic acid administration were ineffective. Also, there appeared to be a delay in development of neurotoxic manifestations (toe-walking gait) but the results were not as consistent as the improvement in survival. Glutamic acid given to tumor-bearing mice (P-388 and P-1534 murine leukemia) did not inhibit the antitumor effect of vincristine-induced host toxicity in a schedule-dependent fashion without inhibition of the antitumor effect of vincristine.     

Paced QRS morphology predicts incident left ventricular systolic dysfunction and atrial fibrillation

Background

The prognostic significance of paced QRS complex morphology on surface ECG remains unclear. This study aimed to assess long-term outcomes associated with variations in the paced QRS complex.

Social and ecological factors alter stress physiology of Virunga mountain gorillas (Gorilla beringei beringei)

Living in a rapidly changing environment can alter stress physiology at the population level, with negative impacts on health, reproductive rates, and mortality that may ultimately result in species decline. Small, isolated animal populations where genetic diversity is low are at particular risks, such as endangered Virunga mountain gorillas (Gorilla beringei beringei). Along with climate change‐associated environmental shifts that are affecting the entire population, subpopulations of the Virunga gorillas have recently experienced extreme changes in their social environment. As the growing population moves closer to the forest's carrying capacity, the gorillas are coping with rising population density, increased frequencies of interactions between social units, and changing habitat use (e.g., more overlapping home ranges and routine ranging at higher elevations). Using noninvasive monitoring of fecal glucocorticoid metabolites (FGM) on 115 habituated Virunga gorillas, we investigated how social and ecological variation are related to baseline FGM levels, to better understand the adaptive capacity of mountain gorillas and monitor potential physiological indicators of population decline risks. Generalized linear mixed models revealed elevated mean monthly baseline FGM levels in months with higher rainfall and higher mean maximum and minimum temperature, suggesting that Virunga gorillas might be sensitive to predicted warming and rainfall trends involving longer, warmer dry seasons and more concentrated and extreme rainfall occurrences. Exclusive use of smaller home range areas was linked to elevated baseline FGM levels, which may reflect reduced feeding efficiency and increased travel efforts to actively avoid neighboring groups. The potential for additive effects of stress‐inducing factors could have short‐ and long‐term impacts on the reproduction, health, and ultimately survival of the Virunga gorilla population. The ongoing effects of environmental changes and population dynamics must be closely monitored and used to develop effective long‐term conservation strategies that can help address these risk factors.     

Climate impacts on transocean dispersal and habitat in gray whales from the Pleistocene to 2100

Arctic animals face dramatic habitat alteration due to ongoing climate change. Understanding how such species have responded to past glacial cycles can help us forecast their response to today's changing climate. Gray whales are among those marine species likely to be strongly affected by Arctic climate change, but a thorough analysis of past climate impacts on this species has been complicated by lack of information about an extinct population in the Atlantic. While little is known about the history of Atlantic gray whales or their relationship to the extant Pacific population, the extirpation of the Atlantic population during historical times has been attributed to whaling. We used a combination of ancient and modern DNA, radiocarbon dating and predictive habitat modelling to better understand the distribution of gray whales during the Pleistocene and Holocene. Our results reveal that dispersal between the Pacific and Atlantic was climate dependent and occurred both during the Pleistocene prior to the last glacial period and the early Holocene immediately following the opening of the Bering Strait. Genetic diversity in the Atlantic declined over an extended interval that predates the period of intensive commercial whaling, indicating this decline may have been precipitated by Holocene climate or other ecological causes. These first genetic data for Atlantic gray whales, particularly when combined with predictive habitat models for the year 2100, suggest that two recent sightings of gray whales in the Atlantic may represent the beginning of the expansion of this species' habitat beyond its currently realized range.     

Dominant Mutations in KAT6A Cause Intellectual Disability with Recognizable Syndromic Features

Through a multi-center collaboration study, we here report six individuals from five unrelated families, with mutations in KAT6A/MOZ detected by whole-exome sequencing. All five different de novo heterozygous truncating mutations were located in the C-terminal transactivation domain of KAT6A: {"type":"entrez-nucleotide","attrs":{"text":"NM_001099412.1","term_id":"150378462","term_text":"NM_001099412.1"}}NM_001099412.1: c.3116_3117 delCT, p.(Ser1039^∗); c.3830_3831insTT, p.(Arg1278Serfs^∗17); c.3879 dupA, p.(Glu1294Argfs^∗19); c.4108G>T p.(Glu1370^∗) and c.4292 dupT, p.(Leu1431Phefs^∗8). An additional subject with a 0.23 MB microdeletion including the entire KAT6A reading frame was identified with genome-wide array comparative genomic hybridization. Finally, by detailed clinical characterization we provide evidence that heterozygous mutations in KAT6A cause a distinct intellectual disability syndrome. The common phenotype includes hypotonia, intellectual disability, early feeding and oromotor difficulties, microcephaly and/or craniosynostosis, and cardiac defects in combination with subtle facial features such as bitemporal narrowing, broad nasal tip, thin upper lip, posteriorly rotated or low-set ears, and microretrognathia. The identification of human subjects complements previous work from mice and zebrafish where knockouts of Kat6a/kat6a lead to developmental defects.     

Studying the Neural Basis of Adaptive Locomotor Behavior in Insects

Studying the neural basis of walking behavior, one often faces the problem that it is hard to separate the neuronally produced stepping output from those leg movements that result from passive forces and interactions with other legs through the common contact with the substrate. If we want to understand, which part of a given movement is produced by nervous system motor output, kinematic analysis of stepping movements, therefore, needs to be complemented with electrophysiological recordings of motor activity. The recording of neuronal or muscular activity in a behaving animal is often limited by the electrophysiological equipment which can constrain the animal in its ability to move with as many degrees of freedom as possible. This can either be avoided by using implantable electrodes and then having the animal move on a long tether (i.e. Clarac et al., 1987; Duch & Pflüger, 1995; Böhm et al., 1997; Gruhn & Rathmayer, 2002) or by transmitting the data using telemetric devices (Kutsch et al, 1993; Fischer et al., 1996; Tsuchida et al. 2004; Hama et al., 2007; Wang et al., 2008). Both of these elegant methods, which are successfully used in larger arthropods, often prove difficult to apply in smaller walking insects which either easily get entangled in the long tether or are hindered by the weight of the telemetric device and its batteries. In addition, in all these cases, it is still impossible to distinguish between the purely neuronal basis of locomotion and the effects exerted by mechanical coupling between the walking legs through the substrate. One solution for this problem is to conduct the experiments in a tethered animal that is free to walk in place and that is locally suspended, for example over a slippery surface, which effectively removes most ground contact mechanics. This has been used to study escape responses (Camhi and Nolen, 1981; Camhi and Levy, 1988), turning (Tryba and Ritzman, 2000a,b; Gruhn et al., 2009a), backward walking (Graham and Epstein, 1985) or changes in velocity (Gruhn et al., 2009b) and it allows the experimenter easily to combine intra- and extracellular physiology with kinematic analyses (Gruhn et al., 2006).We use a slippery surface setup to investigate the timing of leg muscles in the behaving stick insect with respect to touch-down and lift-off under different behavioral paradigms such as straight forward and curved walking in intact and reduced preparations.     

Cathodes as electron donors for microbial metabolism: Which extracellular electron transfer mechanisms are involved?

This review illuminates extracellular electron transfer mechanisms that may be involved in microbial bioelectrochemical systems with biocathodes. Microbially-catalyzed cathodes are evolving for new bioprocessing applications for waste(water) treatment, carbon dioxide fixation, chemical product formation, or bioremediation. Extracellular electron transfer processes in biological anodes, were the electrode serves as electron acceptor, have been widely studied. However, for biological cathodes the question remains: what are the biochemical mechanisms for the extracellular electron transfer from a cathode (electron donor) to a microorganism? This question was approached by not only analysing the literature on biocathodes, but also by investigating known extracellular microbial oxidation reactions in environmental processes. Here, it is predicted that in direct electron transfer reactions, c-type cytochromes often together with hydrogenases play a critical role and that, in mediated electron transfer reactions, natural redox mediators, such as PQQ, will be involved in the bioelectrochemical reaction. These mechanisms are very similar to processes at the bioanode, but the components operate at different redox potentials. The biocatalyzed cathode reactions, thereby, are not necessarily energy conserving for the microorganism.