Cadaverine: a common polyamine in zygotic embryos and somatic embryos of the species Capsicum chinense Jacq.

The behavior of endogenous polyamines was studied in somatic embryos and zygotic embryos of Habanero pepper (Capsicum chinense). In the first part of the work, the polyamine content was evaluated in both types of embryos (somatic and zygotic). As a result, in addition to the common polyamines (putrescine, spermidine and spermine), it was also possible to detect cadaverine, a polyamine rarely found in plants. In general, all the polyamines were found to be more abundant in somatic embryos than in zygotic embryos, with significantly higher contents of putrescine and cadaverine. Subsequently, the content of putrescine, spermidine, spermine and cadaverine, in their different forms (free, bound and conjugated) was determined in somatic embryos which were cultured in non-ventilated and ventilated containers. Detection of polyamines was carried out at 28 and 42 days of culture by the HPLC method. The ethylene content was monitored during the process in both culture conditions (ventilated and non-ventilated). As a result of the analysis, cadaverine was always found present, indicating that it is a common polyamine in the species. Ethylene was detected in containers without ventilation throughout the culture, except during replenishment of the culture medium (R1, R2 and R3). The behavior pattern of each polyamine, analyzed under different culture conditions (ventilated and non-ventilated) and at different moments of culture (28 and 42 days of culture), show that the polyamines are not only involved in morphogenic processes in plants; polyamines are also significantly affected by the surrounding environment. However, the most novel result, presented for the first time in this paper, is that cadaverine is found to be a common polyamine in C. chinense since it is present in both zygotic embryos and somatic embryos.

     

An integrative multidisciplinary approach to understanding cryptic divergence in Brazilian species of the Anastrepha fraterculus complex (Diptera: Tephritidae)

An integrative multidisciplinary approach was used to delimit boundaries among cryptic species within the Anastrepha fraterculus complex in Brazil. Sexual compatibility, courtship and sexual acoustic behaviour, female morphometric variability, variation for the mitochondrial gene COI, and the presence of Wolbachia were compared among A. fraterculus populations from the Southern (Vacaria, Pelotas, Bento Gonçalves, São Joaquim) and Southeastern (Piracicaba) regions of Brazil. Our results suggest full mating compatibility among A. fraterculus populations from the Southern region and partial pre‐zygotic reproductive isolation of these populations when compared with the population from the Southeastern region. A. fraterculus populations from both regions differed in the frequency of courtship displays and aspects of the calling phase and mounting acoustic signal. Morphometric analysis showed differences between Southern region and Southeastern region samples. All populations analyzed were infected with Wolbachia. The trees generated from the COI sequencing data are broadly congruent with the behavioural and morphometric data with the exception of one Southern population. The likely mechanisms by which A. fraterculus populations might have diverged are discussed in detail based on behavioural, morphometric, molecular genetics, and biogeographical studies.     

An information-theoretic analysis of genetics, gender and age in cancer patients

Germline genetics, gender and hormonal-signaling pathways are all well described modifiers of cancer risk and progression. Although an improved understanding of how germline genetic variants interact with other cancer risk factors may allow better prevention and treatment of human cancer, measuring and quantifying these interactions is challenging. In other areas of research, Information Theory has been used to quantitatively describe similar multivariate interactions. We implemented a novel information-theoretic analysis to measure the joint effect of a high frequency germline genetic variant of the p53 tumor suppressor pathway (MDM2 SNP309 T/G) and gender on clinical cancer phenotypes. This analysis quantitatively describes synergistic interactions among gender, the MDM2 SNP309 locus, and the age of onset of tumorigenesis in p53 mutation carriers. These results offer a molecular and genetic basis for the observed sexual dimorphism of cancer risk in p53 mutation carriers and a model is proposed that suggests a novel cancer prevention strategy for p53 mutation carriers.     

Experimental test on public information use in the colonial Lesser Kestrel

The formation of colonies and the evolution of coloniality have been suggested to be a by-product of the use of public information to select breeding habitats. In this study we performed an experimental test to investigate whether the Lesser Kestrel (Falco naumanni) uses breeding success of conspecifics as a source of public information to select a breeding colony. We considered four potential cues based on reproductive performance of conspecifics in each colony: mean and variance of breeding success measured in both all pairs (TRS, total reproductive success), and only successful pairs (PRS, partial reproductive success). Both mean PRS and mean TRS could be predictive cues of the future reproductive output at a given site, because they varied among colonies and were autocorrelated from one year to the next. To dissociate any relationship between habitat quality and reproductive success we manipulated the mean brood sizes by transferring chicks among ten colonies. In five colonies, all the broods with at least two nestlings were reduced in one chick and in other five colonies all broods were enlarged by one chick. In the following year, we found that the number of adult immigrant kestrels settled at a colony was only explained by mean PRS in the previous year. We also examined the settlement of yearlings, which lack of information on breeding success in previous years. Unlike adult immigrant kestrels, yearlings tended to settle more frequently in those colonies with low mean PRS in the previous year, probably because of the lower pressure for occupation in those colonies. A multiple regression analysis showed that the growth of colonies was positively dependent on the mean PRS in the experimental year, and negatively on the number of predated nests. This study provides a solid support to the hypothesis that colonial species can use mean breeding success of successful pairs as a source of public information to make settlement decisions.     

Flavonoids from Erythroxylon argentinum

Quercetin 3-rutinoside, quercetin 3-α-l-rhamnoside, 7,4′-dimethylquercetin 3-rutinoside and the novel glycoside 7,4′-dimethylquercetin 3-rutinoside-5-glucoside have been identified from aerial parts of Erythroxylon argentinum.     

Low Density Lipoproteins Promote Unstable Calcium Handling Accompanied by Reduced SERCA2 and Connexin-40 Expression in Cardiomyocytes

The damaging effects of high plasma levels of cholesterol in the cardiovascular system are widely known, but little attention has been paid to direct effects on cardiomyocyte function. We therefore aimed at testing the hypothesis that Low Density Lipoprotein (LDL) cholesterol affects calcium dynamics and signal propagation in cultured atrial myocytes. For this purpose, mRNA and protein expression levels were determined by real time PCR and western blot analysis, respectively, and intracellular calcium was visualized in fluo-4 loaded atrial HL-1 myocyte cultures subjected to field stimulation. At low stimulation frequencies all cultures had uniform calcium transients at all tested LDL concentrations. However, 500 µg LDL/mL maximally reduced the calcium transient amplitude by 43% from 0.30±0.04 to 0.17±0.02 (p<0.05). Moreover, LDL-cholesterol dose-dependently increased the fraction of alternating and irregular beat-to-beat responses observed when the stimulation interval was shortened. This effect was linked to a concurrent reduction in SERCA2, RyR2, IP3RI and IP3RII mRNA levels. SERCA2 protein levels were also reduced by 43% at 200 µg LDL/mL (p<0.05) and SR calcium loading was reduced by 38±6% (p<0.001). By contrast, HDL-cholesterol had no significant effect on SERCA expression or SR calcium loading. LDL-cholesterol also slowed the conduction velocity of the calcium signal from 3.2+0.2 mm/s without LDL to 1.7±0.1 mm/s with 500 µg LDL/mL (p<0.05). This coincided with a reduction in Cx40 expression (by 44±3%; p<0.05 for mRNA and by 79±2%; p<0.05 for Cx40 protein at 200 µg/ml LDL) whereas the Cx-43 expression did not significantly change. In conclusion, LDL-cholesterol destabilizes calcium handling in cultured atrial myocytes subjected to rapid pacing by reducing SERCA2 and Cx40 expression and by slowing the conduction velocity of the calcium signal.     

Sequence analysis of the first B5 subgenogroup strain of enterovirus 71 isolated in Korea

Journal of Microbiology - Enterovirus A71 (EV71), the main etiological agent of handfoot- mouth disease (HFMD), circulates in many areas of the world and has caused large epidemics since 1997,...