The relationship between hetero-oligomer formation and function of the topological specificity domain of the Escherichia coli MinE protein

MinE is an oligomeric protein that, in conjunction with other Min proteins, is required for the proper placement of the cell division site of Escherichia coli . We have examined the self-association properties of MinE by analytical ultracentrifugation and by studies of hetero-oligomer formation in non-denaturing polyacrylamide gels. The self-association properties of purified MinE predict that cytoplasmic MinE is likely to exist as a mixture of monomers and dimers. Consistent with this prediction, the C-terminal MinE^22–88 fragment forms hetero-oligomers with MinE⁺ when the proteins are co-expressed. In contrast, the MinE^36–88 fragment does not form MinE⁺/MinE^36–88 hetero-oligomers, although MinE^36–88 affects the topological specificity of septum placement as shown by its ability to induce minicell formation when co-expressed with MinE⁺ in wild-type cells. Therefore, hetero-oligomer formation is not necessary for the induction of minicelling by expression of MinE^36–88 in wild-type cells. The interference with normal septal placement is ascribed to competition between MinE^36–88 and the corresponding domain in the complete MinE protein for a component required for the topological specificity of septal placement.     

Estimation of structural components of abnormal human hair from amino acid analyses

A mathematical method is described for using an amino acid analysis for estimating the proportions of the major structural components of human hair. Application of this method to the amino acid composition of hair from malnourished children and from trichothiodystrophic hair suggests its potential usefulness as a diagnostic index, particularly for nutritional status. The possible relevance of the results to the biosynthesis of hair proteins is also discussed.     

Zfra is an inhibitor of Bcl-2 expression and cytochrome c release from the mitochondria

Zfra is a small size 31-amino-acid C2H2 zinc finger-like protein, which is known to interact with c-Jun N-terminal kinase 1 (JNK1), WW domain-containing oxidoreductase (WWOX, FOR or WOX1), TNF receptor-associated death domain protein (TRADD) and nuclear factor kappaB (NF-kappaB) during stress response. Here, we show that Zfra became phosphorylated at Ser8 (as determined by specific antibody) and translocated to the mitochondria in response to inducers of mitochondrial permeability transition (MPT) (e.g. staurosporine and betulinic acid). Overexpressed Zfra induced cell death. This event is associated, in part, with increased dissipation of mitochondrial membrane potential (MMP) and increased chromosomal DNA fragmentation. Intriguingly, Zfra significantly downregulated Bcl-2 and yet blocked cytochrome c release from the mitochondria. Overexpression of an S8G-Zfra mutant (Ser8 to Gly8 alteration) could not induce cell death, probably due to its failure of translocating to the mitochondria and causing MMP dissipation. Over-expressed proapoptotic WOX1 induced cytochrome c release from the mitochondria. Zfra bound and blocked the effect of WOX1. Taken together, Ser8 is essential for overexpressed Zfra to exert cell death via the mitochondrial pathway. Zfra downregulates Bcl-2 and induces MMP dissipation but causes no cytochrome c release, indicating a novel death pathway from the mitochondria.     

Stereotactic body radiotherapy for superior vena cava syndrome

Superior vena cava syndrome (SVCS) is characterized by a spectrum of clinical findings that result from the occlusion of the superior vena cava (SVC), usually caused by extracaval compression of the SVC by either a bronchogenic tumor or an enlarged mediastinal lymph node. Most efforts at treatment for SVCS are palliative, and long-term survival for malignancy-related SVCS is very low. Therefore, radiotherapy treatment is usually delivered with palliative intent utilizing hypofractionated regimens. The use of high dose per fraction may result in more rapid and more durable responses to treatment. Similarly, the high dose per fraction utilized in stereotactic body radiotherapy (SBRT) has been proven highly efficacious in treating early stage non-small cell lung cancer (NSCLC). Here we report the first reported case of a patient with SVCS from NSCLC successfully treated with SBRT to alleviate SVCS.     

Tributes to Truman G. Yuncker and Ethel Claflin Yuncker

Editor’s note: This tribute was prepared by Barbara Yuncker from a recorded interview she had with Dr. Callejas during his six-week visit to the Garden’s Herbarium in September 1988 to study the Piperaceae specimens received from DePauw University.     

Status and prospects for renewable energy using wood pellets from the southeastern United States

The ongoing debate about costs and benefits of wood‐pellet based bioenergy production in the southeastern United States (SE USA) requires an understanding of the science and context influencing market decisions associated with its sustainability. Production of pellets has garnered much attention as US exports have grown from negligible amounts in the early 2000s to 4.6 million metric tonnes in 2015. Currently, 98% of these pellet exports are shipped to Europe to displace coal in power plants. We ask, ‘How is the production of wood pellets in the SE USA affecting forest systems and the ecosystem services they provide?’ To address this question, we review current forest conditions and the status of the wood products industry, how pellet production affects ecosystem services and biodiversity, and what methods are in place to monitor changes and protect vulnerable systems. Scientific studies provide evidence that wood pellets in the SE USA are a fraction of total forestry operations and can be produced while maintaining or improving forest ecosystem services. Ecosystem services are protected by the requirement to utilize loggers trained to apply scientifically based best management practices in planning and implementing harvest for the export market. Bioenergy markets supplement incomes to private rural landholders and provide an incentive for forest management practices that simultaneously benefit water quality and wildlife and reduce risk of fire and insect outbreaks. Bioenergy also increases the value of forest land to landowners, thereby decreasing likelihood of conversion to nonforest uses. Monitoring and evaluation are essential to verify that regulations and good practices are achieving goals and to enable timely responses if problems arise. Conducting rigorous research to understand how conditions change in response to management choices requires baseline data, monitoring, and appropriate reference scenarios. Long‐term monitoring data on forest conditions should be publicly accessible and utilized to inform adaptive management.     

THE GROWTH OF BACTERIOPHAGE

1. An anti-Escherichia coli phage has been isolated and its behavior studied. 2. A plaque counting method for this phage is described, and shown to give a number of plaques which is proportional to the phage concentration. The number of plaques is shown to be independent of agar concentration, temperature of plate incubation, and concentration of the suspension of plating bacteria. 3. The efficiency of plating, i.e. the probability of plaque formation by a phage particle, depends somewhat on the culture of bacteria used for plating, and averages around 0.4. 4. Methods are described to avoid the inactivation of phage by substances in the fresh lysates. 5. The growth of phage can be divided into three periods: adsorption of the phage on the bacterium, growth upon or within the bacterium (latent period), and the release of the phage (burst). 6. The rate of adsorption of phage was found to be proportional to the concentration of phage and to the concentration of bacteria. The rate constant k_a is 1.2 x 10^–9 cm.⁸/min. at 15°C. and 1.9 x 10^–9 cm.⁸/min. at 25°. 7. The average latent period varies with the temperature in the same way as the division period of the bacteria. 8. The latent period before a burst of individual infected bacteria varies under constant conditions between a minimal value and about twice this value. 9. The average latent period and the average burst size are neither increased nor decreased by a fourfold infection of the bacteria with phage. 10. The average burst size is independent of the temperature, and is about 60 phage particles per bacterium. 11. The individual bursts vary in size from a few particles to about 200. The same variability is found when the early bursts are measured separately, and when all the bursts are measured at a late time.