Genetic variants of ghrelin in metabolic disorders

An increasing understanding of the role of genes in the development of obesity may reveal genetic variants that, in combination with conventional risk factors, may help to predict an individual's risk for developing metabolic disorders. Accumulating evidence indicates that ghrelin plays a role in regulating food intake and energy homeostasis and it is a reasonable candidate gene for obesity-related co-morbidities. In cross-sectional studies low total ghrelin concentrations and some genetic polymorphisms of ghrelin have been associated with obesity-associated diseases. The present review highlights many of the important problems in association studies of genetic variants and complex diseases. It is known that population-specific differences in reported associations exist. We therefore conclude that more studies on variants of ghrelin gene are needed to perform in different populations to get deeper understanding on the relationship of ghrelin gene and its variants to obesity.     

Baeopterogyna mihalyii Matile (Diptera, Mycetophilidae): association of sexes using morphological and molecular approaches with the first description of females

Both males and females of Baeopterogyna mihalyiiMatile, 1975 are recorded from northern Greece. Females are described for the first time providing photographs of the general facies and terminalia. In contrast to the single congener with stenopterous females - Baeopterogyna nudipes Vockeroth, 1972 - Baeopterogyna mihalyii is shown to have normally developed wings in both sexes. Association of sexes is based on both morphological characters and sequence data from cytochrome oxidase subunit one (COI). DNA sequences are used for the first time for the association of sexes in Mycetophilidae.     

Indigenous woody species diversity in Eucalyptus globulus Labill. ssp. globulus plantations in the Ethiopian highlands

The naturally regenerated native woody species diversity was studied ineucalypt plantations at Menagesha, where there was remnant natural forest, and atChancho, where natural forests were absent. A total of 22 and 20 woody speciesbelonging to 18 and 17 families were found, and of these species, treesaccounted for 68 and 55% at Menagesha and Chancho, respectively. About 83% ofthe woody species found in the adjacent natural forest, including importanttimber species were represented in the eucalypt understory at Menagesha.However, the relative abundance of species in eucalypt plantations and theadjacent natural forest varied considerably. Woody species richness andabundance of sample plots at Menagesha were on average 2.4 times and 5.7times higher, respectively, than the sample plots at Chancho. This resultdemonstrates the crucial role of the remnant small patches of natural forest,as a source of diaspores for the restoration of the woody species diversity indegraded areas of the Ethiopian highlands. There was no significant differencein woody species diversity between the eucalypt stand margin and centre. Theunderstory woody species density in eucalypt plantations was up to 8325stems/ha, indicating that the numerous eucalypt stands have a highpotential for restoring the woody species diversity in the Ethiopian highlands.In order to fully re-establish the diverse and economically valuable naturalforest, complementary measures such as enrichment planting of missing primaryforest species may be required.     

Association between Randall's plaque and calcifying nanoparticles

Objectives

Randall initially described calcified subepithelial papillary plaques, which he hypothesized as nidi for urinary calculi. The discovery of calcifying nanoparticles (CNP), also referred to as nanobacteria, in calcified soft tissues has raised another hypothesis about their possible involvement in urinary stone formation. This research is the first attempt to investigate the potential association of these two hypotheses.

Methods

We collected renal papilla and blood samples from 17 human patients who had undergone laparoscopic nephrectomy. Immunohistochemical staining (IHS) was applied using monoclonal antibody (mAb) against CNP. Homogenized papillary tissues and serum samples were cultured for CNP. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were performed on papillary samples. Serum samples were tested for CNP antigen and antibody with enzyme-linked immunosorbent assay (ELISA).

Results

Randall’s plaques (RP) were visible on gross inspection in 11 out of 17 samples. IHS was positive for CNP antigen in 8 of the visually positive samples, but in only 1 of the remaining samples. SEM revealed spherical apatite-formations in 14 samples confirmed by EDS analysis. In cultures, all serum samples and 13 tissue homogenates grew CNP. In ELISA, 14 samples were positive for CNP-antigen and 11 samples were positive for CNP-antibody.

Conclusion

There was evidence of a link between detection of CNP and presence of RP. Although causality was not demonstrated, these results suggest that further studies with negative control samples should be made to explore the etiology of RP formation, thus leading to a better understanding of the pathogenesis of stone formation.     

Role of Ghrelin Polymorphisms in Obesity Based on Three Different Studies

Objective: Associations between preproghrelin DNA variants and obesity‐related phenotypes were studied in 3004 subjects from the Québec Family Study (QFS), the HERITAGE Family Study (HERITAGE), and the Swedish Obese Subjects (SOS) Study. Research Methods and Procedures: Body mass index (BMI), fat mass (FM) from underwater weighing, and abdominal fat from computerized tomography were measured. The ghrelin polymorphisms were identified by polymerase chain reaction. Results: Arg51Gln QFS subjects (n = 6) had lower ghrelin concentrations (p = 0.007) than Arg51Arg subjects (n = 14). White preproghrelin Met72Met subjects in HERITAGE had the lowest BMI (p = 0.020), and those in the QFS cohort had the lowest FM (p < 0.001). Met72 carrier status (Met72+) was associated with lower FM (p = 0.026) and higher insulin‐like growth factor‐1 levels (p = 0.019) among blacks. Met72Met QFS subjects had less visceral fat (p = 0.002) and a lower fasting respiratory quotient (p = 0.037). HERITAGE Met72+ white subjects also showed lower exercise respiratory quotient (p = 0.030) and higher maximal oxygen uptake (p = 0.023). Furthermore, the prevalence of Met72+ was higher (19.2%; p < 0.05) in SOS subjects whose BMI was ≤25 kg/m² than in those with BMI >25 kg/m² (14.8%). SOS Met72+ obese women had a lower (11.4%; p = 0.032) prevalence of hypertension than noncarriers (23.9%). Discussion: Arg51Gln mutation was associated with lower plasma ghrelin levels but not with obesity. The preproghrelin Met72 carrier status seems to be protective against fat accumulation and associated metabolic comorbidities.     

Independent activation of cold acclimation by low temperature and short photoperiod in hybrid aspen

Temperate zone woody plants cold acclimate in response to both short daylength (SD) and low temperature (LT). We were able to show that these two environmental cues induce cold acclimation independently by comparing the wild type (WT) and the transgenic hybrid aspen (Populus tremula x Populus tremuloides Michx.) line 22 overexpressing the oat (Avena sativa) PHYTOCHROME A gene. Line 22 was not able to detect the SD and, consequently, did not stop growing in SD conditions. This resulted in an impaired freezing tolerance development under SD. In contrast, exposure to LT resulted in cold acclimation of line 22 to a degree comparable with the WT. In contrast to the WT, line 22 could not dehydrate the overwintering tissues or induce the production of dehydrins (DHN) under SD conditions. Furthermore, abscisic acid (ABA) content of the buds of line 22 were the same under SD and long daylength, whereas prolonged SD exposure decreased the ABA level in the WT. LT exposure resulted in a rapid accumulation of DHN in both the WT and line 22. Similarly, ABA content increased transiently in both the WT and line 22. Our results indicate that phytochrome A is involved in photoperiodic regulation of ABA and DHN levels, but at LT they are regulated by a different mechanism. Although SD and LT induce cold acclimation independently, ABA and DHN may play important roles in both modes of acclimation.