Growth hormone signaling is necessary for lifespan extension by dietary methionine

Growth hormone significantly impacts lifespan in mammals. Mouse longevity is extended when growth hormone (GH) signaling is interrupted but markedly shortened with high‐plasma hormone levels. Methionine metabolism is enhanced in growth hormone deficiency, for example, in the Ames dwarf, but suppressed in GH transgenic mice. Methionine intake affects also lifespan, and thus, GH mutant mice and respective wild‐type littermates were fed 0.16%, 0.43%, or 1.3% methionine to evaluate the interaction between hormone status and methionine. All wild‐type and GH transgenic mice lived longer when fed 0.16% methionine but not when fed higher levels. In contrast, animals without growth hormone signaling due to hormone deficiency or resistance did not respond to altered levels of methionine in terms of lifespan, body weight, or food consumption. Taken together, our results suggest that the presence of growth hormone is necessary to sense dietary methionine changes, thus strongly linking growth and lifespan to amino acid availability.     

Inheritance of self-compatibility in almond: breeding strategies to assure self-compatibility in the progeny

To assure self-compatibility in the progenies, three different crosses were conducted for the first time in an almond breeding programme: self-pollination (266 descendants from 30 families), crosses between parents sharing an S-allele (108 descendants from five families) and crosses with homozygous self-compatible parents (62 descendants from five families). Depending on the cross, self-compatibility in the progenies was determined by observing pollen tube growth (by means of fluorescence microscopy), stylar S-RNases analysis or allele-specific PCR. The results obtained fit with the accepted hypothesis of inheritance of self-compatibility and the three crossing strategies used ensured 100% of self-compatible descendants. These strategies increase the efficiency of the breeding programme and avoid the laborious task of evaluating this characteristic. From the breeding point of view, self-fertilisation and crosses between relatives tend to produce inbreeding. Furthermore, these methods reduce the possibilities of choosing the parental combination. The use of homozygous self-compatible parents does not have any of these disadvantages. As far as we know, this is the first time that allele-specific PCR has been used for early selection of self-compatible seedlings. The advantages and disadvantages of the three methodologies used to determine self-compatibility are discussed.     

Kaurenic acid derivatives from Stevia eupatoria

Two kaurene type diterpenes were isolated from the aerial part of Stevia euphoria. Their structures and stereochemistry were established by carbon and ¹H NMR, chemical transformation and correlation with known compounds.     

Viability and mushroom production of Lentinula edodes and L. boryana strains (Fungi: Basidiomycetes) after cryogenic storage of spawn stocks

The viability of two strains of Lentinula edodes and two of L. boryana under cryogenic storage during 1 week has been studied from the evaluation of five contact periods (1, 1.5, 2, 3 and 5 h) of the cryoprotector, glycerol 10% (v/v), with the mycelium. On average, 99.25% of samples were recovered, 1.5 h being the best contact period. Afterwards, samples of the strains, before and after the cryogenic process, were cultivated at a pilot plant using a mix of Carpinus carolineana sawdust, rice bran and sorghum grains as substrate. The evaluation parameters were: days of incubation, primordia initiation, number of flushes, fruiting body sizes and biological efficiency (EB). Only L. edodes developed carpophores. On average, 3–4 flushes were obtained, which reached EB of 67.1 ± 30.7 to 74.7 ± 24.5 with no statistical differences detected between the yields. The majority of fructification sizes ranged from 5 to 14.9 cm. Morphological differences between the samples before and after the treatment were not observed.     

Nonheterochronic developmental changes underlie morphological heterochrony in the evolution of the Ardeidae

Evolutionary changes in developmental timing and rates (heterochrony) are a source of morphological variation. Here we explore a central issue in heterochronic analysis: are the alterations in developmental timing and rates the only factor underlying morphological heterochrony? Tarsometatarsal growth through endochondral ossification in Ardeidae evolution has been taken as a case study. Evolutionary changes in bone growth rate (morphological heterochrony) might be either (a) the result of alterations in the mitotic frequency of epiphyseal chondrocytes (process‐heterochrony hypothesis), or (b) the outcome of alterations in the number of proliferating cells or in the size of hypertrophic chondrocytes (structural hypothesis). No correlation was found between tarsometatarsal growth rates and the frequency of cell division. However, bone growth rates were significantly correlated with the number of proliferating cells. These results support the structural hypothesis: morphological acceleration and deceleration are the outcome of evolutionary changes in one structural variable, the number of proliferating cells.     

A modeling procedure to predict cancer risks associated with inhalable oil dust from Kuwait oil lakes

A model was constructed to estimate cancer risks associated with PM₁₀‐bound polycydic aromatic hydrocarbons (PAHs) from Kuwait oil lakes. The design of the risk model was based on a conceptual “chain of events”; leading from levels of PAH compounds in oil lakes, erosion of oil dust and input into the atmosphere, to contaminant concentration in air, to actual human exposure in residential areas. Uncertainties in the “chain of events”; model were addressed using Monte Carlo techniques. To identify the exposure duration of concern [duration beyond which risk becomes unacceptable (i.e. Risk > 10^‐6)], four exposure durations were tested 10, 20, 40, 70 years. 40 years was identified to be the exposure duration of concern based on the 95th percen‐tile of the risk distribution. As a result, the acceptability of risk was specified in terms of a single constraint on the 95^th percentile of the risk distribution evaluated after 40 years of exposure: 0 < Risk (40 y)₀.₉₅ ≤ 10^‐6. Based on this constraint, it was estimated that a removal rate of 217, 793.27 m³/year to be an adequate action for risk management. The northern oil lakes were identified as the lakes of most concern when inhalation exposures are considered.     

Effects of sample re-sequencing and trimming on the quality and size of assembled consensus sequences

The production of nucleic acid sequences by automatic DNA sequencer machines is always associated with some base-calling errors. In order to produce a high-quality DNA sequence from a molecule of interest, researchers normally sequence the same sample many times. Considering base-calling errors as rare events, re-sequencing the same molecule and assembling the reads produced are frequently thought to be a good way to generate reliable sequences. However, a relevant question on this issue is: how many times the sample needs to be re-sequenced to minimize costs and achieve a high-fidelity sequence? We examined how both the number of re-sequenced reads and PHRED trimming parameters affect the accuracy and size of final consensus sequences. Hundreds of single-pool reaction pUC18 reads were generated and assembled into consensus sequences with CAP3 software. Using local alignment against the published pUC18 cloning vector sequence, the position and number of errors in the consensus were identified and stored in MySQL databases. Stringent PHRED trimming parameters proved to be efficient for the reduction of errors; however, this procedure also decreased consensus size. Moreover, re-sequencing did not have a clear effect on the removal of consensus errors, although it was able to slightly increase consensus.