Structural modifications modulate stability of glutathione-activated arylated diazeniumdiolate prodrugs

JS-K, a diazeniumdiolate-based nitric oxide (NO)-releasing prodrug, is currently in late pre-clinical development as an anti-cancer drug candidate. This prodrug was designed to be activated by glutathione (GSH) to release NO. To increase the potency of JS-K, we are investigating the effect of slowing the reaction of the prodrugs with GSH. Herein, we report the effect of replacement of nitro group(s) by other electron-withdrawing group(s) in JS-K and its homo-piperazine analogues on GSH activation and the drugs' biological activity. We show that nitro-to-cyano substitution increases the half-life of the prodrug in the presence of GSH without compromising the compound's in vivo antitumor activity.     

Evidence for a nigro-pulvinar-lateralis posterior complex projection in the cat using horseradish peroxidase neuronal retrograde technique

The possible existence of a direct projection from the substantia nigra to the pulvinar-lateral posterior complex (Pul-LP) was investigated in the cat by using the horseradish peroxidase technique. In particular horseradish peroxidase was injected in the Pul-LP of 8 animals, either unilaterally or bilaterally. Tissue sections obtained from the cat's brain 24-48 hrs. after injection were prepared according to Mesulam's method as slightly modified by the authors. Retrogradelly labelled neurons were observed in substantia nigra pars lateralis and reliculata ipsilaterally to the injected pulvinar-lateral posterior complex. A small number of labelled cells were also found in the contralateral substantia nigra. These findings demonstrate the existence of a close connection between two system which are involved in turning behavior: the nigrostriatal and the pulvinar-lateral posterior complex-superior colliculus.     

DNA reassociation kinetics and hybridization in different angiosperms

Reassociation kinetics ofDaucus carota andPetroselinum crispum (Apiaceae), andDatura innoxia (Solanaceae) are presented. Hybridization of³H-labelled DNA of two carrot cultivars indicate strong qualitative homologies of DNA sequences; nevertheless, certain quantitative differences in some Cotregions seem to exist. However, homologous sequences ofDaucus DNA with DNA ofDatura, and, suprisingly, even with DNA ofPetroselinum are very restricted: between 8% in the repeated regions and ca. 7–9% in the unique regions.     

Risk Communications: Around the World Neural Network Models for Assessing Road Suitability for Dangerous Goods Transport

This article describes a methodology for assessing the degree of remedial action required to make short stretches of a roadway suitable for dangerous goods transport (DGT). The methodology is based on the evaluation of a set of variables that have a bearing on DGT risk. The large number of variables involved made it necessary to apply a supervised approach based on expert criteria. The result was a knowledge base that can be used both to estimate DGT risk for new stretches of roadway and to determine sources of risk without having to rely on an expert. A number of multivariate statistical analysis techniques were tested for the construction of the model, namely linear discriminant analysis with a prior reduction in dimensionality, multilayer perceptrons, and support vector machines. The results obtained from a test sample show that the support vector machines represented expert knowledge most reliably. A graphic representation of the risk index for a studied stretch of roadway results in a map of the level of DGT risk for that roadway.     

Increased dithiothreitol-insensitive,type 2 angiotensin II receptors in selected brain areas of young rats

1. Angiotensin II receptors have been studied by quantitative autoradiography in selected brain areas of young (2-week-old) and adult (8-week-old) rats. 2. In young rats, angiotensin II receptors were present in brain areas which did not express receptors in the adult brain, such as thalamic nuclei, cortical areas, and the cerebellum. 3. Young rats had more angiotensin II receptors in the subfornical organ than adult rats. In the inferior olive, the number of angiotensin receptors in young animals was 10 times higher than that in adult rats. Angiotensin II binding in the inferior olive was insensitive to incubation in the presence of dithiothreitol. 4. Conversely, the number of angiotensin II receptors in the nucleus of the solitary tract was lower in young rats compared to adults. Incubation in the presence of dithiothreitol resulted in a more than 90% inhibition of angiotensin II binding in the nucleus of the solitary tract. 5. Our results indicate the presence of two types of angiotensin II receptor in brain, one sensitive (type 1) and one insensitive (type 2) to the reducing agent dithiothreitol. 6. The expression of type 2 angiotensin II receptors, insensitive to dithiothreitol, is more marked in young rats, indicating a role for this type of angiotensin receptors in brain development.     

Rethinking the importance of the structure of ecological networks under an environment‐dependent framework

A major quest in network and community ecology has been centered on understanding the importance of structural patterns in species interaction networks—the synthesis of who interacts with whom in a given location and time. In the past decades, much effort has been devoted to infer the importance of a particular structure by its capacity to tolerate an external perturbation on its structure or dynamics. Here, we demonstrate that such a perspective leads to inconsistent conclusions. That is, the importance of a network structure changes as a function of the external perturbations acting on a community at any given point in time. Thus, we discuss a research agenda to investigate the relative importance of the structure of ecological networks under an environment‐dependent framework. We hypothesize that only by studying systematically the link between network structure and community dynamics under an environment‐dependent framework, we can uncover the limits at which communities can tolerate environmental changes.     

Single step recombinant human growth hormone (rhGH) purification from milk by peptide affinity chromatography

Recombinant human growth hormone (rhGH) is used for the treatment of several pathologies, most of them related to growth. Although different expression systems can be used for its production, the milk from transgenic cows is one of the most interesting due to the high rhGH level achieved (5 g/L). We have designed and synthesized short peptides (9 or 10 amino acid long) using Fmoc chemistry and studied their ability to purify rhGH from milk once immobilized on an agarose support. Using spiked milk with the hormone as a sample, rhGH was purified with 88% yield and 92% purity in a single step with a fold purification of 4.5. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:999–1005, 2018