Chemodiversity of Nonacosan‐10‐ol and n‐Alkanes in the Needle Wax of Pinus heldreichii

This is the first report of individual variability and population diversity of the contents of nonacosan‐10‐ol and n‐alkanes in the needle cuticular waxes of Bosnian pines originated from Montenegro, regarded as Pinus heldreichii var. leucodermis, and from Serbia, regarded as P. heldreichii var. pan?i?i. The amount of nonacosan‐10‐ol varied individually from 27.4 to 73.2% (55.5% in average), but differences between the four investigated populations were not statistically confirmed. The size of the n‐alkanes ranged from C₁₈ to C₃₃. The most abundant n‐alkanes were C₂₃, C₂₇, and C₂₅ (12.2, 11.2, and 10.8% in average, resp.). The carbon preference index (CPI) of the n‐alkanes ranged from 0.8 to 3.1 (1.6 in average), while the average chain length (ACL) ranged from 20.9 to 26.5 (24.4 in average). Long‐chain and mid‐chain n‐alkanes prevailed (49.6 and 37.9% in average, resp.). It was also found that the populations of P. heldreichii var. leucodermis had predominantly a narrower range of n‐alkanes (C₁₈? C₃₁) than the trees of the variety pan?i?i (C₁₈? C₃₃). Differences between the varieties were also significant for most of the other characteristics of the n‐alkane pattern (e.g., most abundant n‐alkanes, CPI, ACL, and relative proportion of short‐, mid‐, and long‐chain n‐alkanes). The principle component and cluster analyses of eleven n‐alkanes confirmed the significant diversity of these two varieties.     

Composition of n‐Alkanes in Natural Populations of Pinus nigra from Serbia – Chemotaxonomic Implications

This is the first report on the composition and variability of the needle‐wax n‐alkanes in natural populations of Pinus nigra in Serbia. Samples of 195 trees from seven populations belonging to several infraspecific taxa (ssp. nigra, var. gocensis, ssp. pallasiana, and var. banatica) were analyzed. In general, the size of the n‐alkanes ranged from C₁₆ to C₃₃, with the exception of ssp. nigra, for which it ranged from C₁₈ to C₃₃. The most abundant were C₂₃‐, C₂₅‐, C₂₇‐, and C₂₉‐alkanes. The needle waxes of Populations I–III and V were characterized by a higher content of C₂₃‐, C₂₅‐, and C₂₇‐alkanes and a lower content of C₂₄‐, C₂₆‐, C₂₈‐, and C₃₀‐alkanes, compared to the other populations, and the trees of these populations could be assigned to ssp. nigra. The samples of Population VI were characterized by higher amounts of C₂₂‐, C₂₄‐, C₃₀‐, and C₃₂‐alkanes and lower amounts of C₂₅‐ and C₂₇‐alkanes, and the trees could be considered as ssp. pallasiana. The samples of Population VII, consisting of trees belonging to var. banatica, were richer in C₂₉‐, C₃₁‐, and C₃₃‐alkanes. The wax compositions of Populations IV and V, both composed of trees previously determined as P. nigra var. gocensis, showed a tendency of splitting. Indeed, the alkane composition of Population IV was closer to that of ssp. pallasiana pines, while that of Population V was more similar to that of ssp. nigra pines. From the results presented here, it is obvious that in the central part of the Balkan Peninsula, significant diversification and differentiation of the populations of black pine exists, and these populations could be defined as different intraspecific taxa. Our results also indicate the validity of n‐alkanes as chemotaxonomic characters within this aggregate.     

The eIF4E RNA regulon promotes the Akt signaling pathway

Eukaryotic initiation factor 4E (eIF4E) promotes cellular proliferation and can rescue cells from apoptotic stimuli such as serum starvation. However, the mechanisms underlying apoptotic rescue are not well understood. In this study, we demonstrate that eIF4E overexpression leads to enhanced survival signaling through Akt and that eIF4E requires Akt1 to rescue serum-deprived fibroblasts. Furthermore, a mutant form of eIF4E (W73A), which is messenger RNA (mRNA) export competent but does not promote translation, rescues cells as readily as wild-type eIF4E. We show that eIF4E mediates Akt activation via up-regulation of Nijmegen breakage syndrome 1 (NBS1), a phosphoinositide-3 kinase-Akt pathway upstream activator. Additionally, eIF4E coordinately up-regulates the expression of downstream effectors of the Akt pathway, thereby amplifying Akt signaling effects. A negative regulator of eIF4E, the promyelocytic leukemia protein (PML), suppresses Akt activation and apoptotic rescue. These PML activities likely arise, at least in part, through its inhibition of eIF4E-mediated NBS1 mRNA export. In summary, eIF4E coordinately regulates gene expression to potentiate Akt activation, an activity required for apoptotic rescue.     

Quality of chemically modified hemp fibers

Hemp fibers are very interesting natural material for textile and technical applications now. Applying hemp fibers to the apparel sector requires improved quality fibers. In this paper, hemp fibers were modified with sodium hydroxide solutions (5% and 18% w/v), at room and boiling temperature, for different periods of time, and both under tension and slack, in order to partially extract noncellulosic substances, and separate the fiber bundles. The quality of hemp fibers was characterised by determining their chemical composition, fineness, mechanical and sorption properties. The modified hemp fibers were finer, with lower content of lignin, increased flexibility, and in some cases tensile properties were improved. An original method for evaluation of tensile properties of hemp fibers was developed.     

Alleviation of Cadmium Toxicity by Naphthenate Treatment

The work is concerned with the effect of low concentrations (10^–7 mol dm^–3) of sodium naphthenate on total content of Cd and its particular forms in the intercellular space and inside cells, as well as on some physiological and biochemical parameters of young soybean plants grown in the presence of 1 mmol dm^–3 solution of cadmium chloride. Presence of naphthenate reduced in average by 40 % content total and intracellular Cd in root, stem and leaves and alleviated the harmful effect of Cd on activity of nitrate reductase and content of photosynthetic pigments.     

Ribavirin targets eIF4E dependent Akt survival signaling

The eukaryotic translation initiation factor eIF4E is dysregulated in many cancers. eIF4E, through its mRNA export and translation functions, combinatorially modulates the expression of genes involved in Akt dependent survival signaling. For these activities, eIF4E must bind the 7-methyl guanosine (m⁷G) cap moiety on the 5′-end of mRNAs. We demonstrate that a physical mimic of the m⁷G cap, ribavirin, inhibits eIF4E dependent Akt survival signaling. Specifically, ribavirin impairs eIF4E mediated Akt activation via inhibiting the production of an upstream activator of Akt, NBS1. Consequently, ribavirin impairs eIF4E dependent apoptotic rescue. A ribavirin analog with distinct physico-chemical properties, tiazofurin, does not impair eIF4E activity indicating that only analogs that mimic the m⁷G cap will inhibit eIF4E function. Ribavirin represents a first-in-class strategy to inhibit eIF4E dependent cancers, through competition for m⁷G cap binding. Thus, ribavirin coordinately impairs eIF4E dependent pathways and thereby, potently inhibits its biological effects.     

An improved clearing method for GUS assay inArabidopsis endosperm and seeds

Precise cellular localization of the GUS stain is notoriously difficult inArabidopsis seeds. Here we report an improved protocol for the clearing of seeds after GUS staining. Incubation in ethanol-acetic acid (EtAc) and Hoyer’s medium allows reliable cellular localization of the GUS, even in seeds from late developmental stages. This method also leads to the staining of nucleoli in the endosperm and embryo, facilitating nuclear counts in endosperm development. An erratum to this article is available at .     

Effect of the acclimation to high environmental temperature on the activity of hepatic glycogen phosphorylase (a+b and a), liver glycogen content and blood glucose level in rats

(1) Changes in the activity of hepatic glycogen phosphorylase a+b and a (GPh-ase a+b and a), liver glycogen content and blood glucose level during acclimation to moderate high environmental temperature (35±1 °C) were studied. (2) Experiments were carried out on adult fed Wistar rats of both sexes, previously given either short-term (1, 4 and 7 days) or long-term (14, 21, 30 and 60 days) exposure to high environmental temperature. The controls were continuously kept at room temperature (20±2 °C). (3) The results obtained showed that in the period of short-term exposure the liver glycogen content was decreased significantly (after the first and fourth days in male rats and after first day in female rats) and the GPh-ase a activity increased (after first day in male rats and after first, fourth and seventh day in female rats). Long-term exposure caused significant increased liver glycogen content (beginning from the 14th day in male rats and the 21st day in female rats) until the end of the acclimation period (60 days). The elevated activity of GPh-ase a persists after 14th day of exposure only in female rats while there are no significant changes over the rest of the acclimation period in both sexes. There were no significant changes in total GPh-ase activity during the whole period of exposure. Blood glucose level was significantly decreased throughout the whole period of acclimation to high environmental temperature, in both sexes (except in the 1 day exposed groups). (4) The increased activity of hepatic GPh-ase a and decreased glycogen content suggested that the short-term exposure to heat stimulates the glycogenolytical processes. Decreased blood glucose level, and elevated liver glycogen content (r=-0.7467 in male and r=-0.6548 in female rats) suggested that prolonged exposure to high environmental temperature stimulated glycogenogenesis, without changes in the GPh-ase activity.     

Aeromonas spp.-mediated cell-contact cytotoxicity is associated with the presence of type III secretion system

In the study we examined the production of cytotonic and cytotoxic toxins and the presence of a type III secretion system (TTSS) in 64 Aeromonas spp. strains isolated from fecal specimens of patients with gastroenteritis. We observed that contact of the bacteria with host epithelial cells is a prerequisite for their cytotoxicity at 3 h incubation. Cell-contact cytotoxic activity of the strains was strongly associated with the presence of the TTSS. Culture supernatants of the strains induced low cytotoxicity effects at the same time of incubation. Cell-free supernatants of 61 (95%) isolates expressed cytotoxic activity which caused the destruction of HEp-2 cells at 24 h. Moreover, 44% strains were cytotonic towards CHO cells and 46% of strains invaded epithelial cells.     

Evolutionary contingency and SETI revisited

The well-known argument against the Search for ExtraTerrestrial Intelligence (SETI) due to George Gaylord Simpson is re-analyzed almost half a century later, in the light of our improved understanding of preconditions for the emergence of life and intelligence brought about by the ongoing “astrobiological revolution”. Simpson’s argument has been enormously influential, in particular in biological circles, and it arguably fueled the most serious opposition to SETI programmes and their funding. I argue that both proponents and opponents of Simpson’s argument have occasionally mispresented its core content. Proponents often oversimplify it as just another consequence of biological contingency, thus leaving their position open to general arguments limiting the scope of contingency in evolution (such as the recent argument of Geerat Vermeij based on selection effects in the fossil record). They also tend to neglect that the argument has been presented as essentially atemporal, while referring to entities and processes that are likely to change over time; this has become even less justifiable as our astrobiological knowledge increased in recent years. Opponents have failed to see that the weaknesses in Simpson’s position could be removed by restructuring of the argument; I suggest one way of such restructuring, envisioned long ago in the fictional context by Stanislaw Lem. While no firm consensus has emerged on the validity of Simpson’s argument so far, I suggest that, contrary to the original motivation, today it is less an anti-SETI argument, and more an astrobiological research programme. In this research programme, SETI could be generalized into a platform for testing some of the deepest assumptions about evolutionary continuity and the relative role of contingency versus convergence on unprecedented spatial and temporal scales.