Rapid Homogenization of Multiple Sources: Genetic Structure of a Recolonizing Population of Fishers

Abstract: Fishers (Martes pennanti) were extirpated from much of southern Ontario, Canada, prior to the 1950s. We hypothesised that the recent recolonization of this area originated from an expansion of the population in Algonquin Provincial Park, which historically served as a refuge for fishers. To test this hypothesis, we created a sampling lattice to encompass Algonquin and the surrounding area, and we collected contemporaneous DNA samples. We sampled fishers from each of 35 sites and genotyped them at 16 microsatellite loci. Using a Bayesian assignment approach, with no a priori geographic information, we inferred 5 discrete genetic populations and used genetic population assignment as a means to cluster sites together. We concluded that the Algonquin Park fisher population has not been a substantial source for recolonization and expansion, which has instead occurred from a number of remnant populations within Ontario, Quebec, and most recently from the Adirondacks in New York, USA. The genetic structure among sampling sites across the entire area revealed a pattern of isolation-by-distance (IBD). However, an examination of the distribution of genetic structure (F_ST/1^- F_ST) at different distances showed higher rates of gene flow than predicted under a strict IBD model at small distances (40 km) within clusters and at larger distances up to 100 km among clusters. This pattern of genetic structure suggests increased migration and gene flow among expanding reproductive fronts.     

The regulatory effects of clomiphene and tamoxifen on mTOR and LC3-II expressions in relation to autophagy in experimental polycystic ovary syndrome (PCOS)

Molecular Biology Reports - Polycystic ovary syndrome (PCOS) is a metabolic disease that causes infertility due to anovulation in women in reproductive age. It is known that clomiphene citrate (CC)...     

Differential survival and reproduction in colour forms of Philaenus spumarius give new insights to the study of its balanced polymorphism

1. Colour polymorphisms are common across animals and are often the result of complex selection regimes. Philaenus spumarius (Linnaeus) (Hemiptera, Aphrophoridae) shows a widely studied dorsal colour polymorphism with several described phenotypes whose variation in their occurrence and frequency, as well as their maintenance across time, have been reported. Several selective influences have been suggested to play a role, but the mechanisms underlying the maintenance of this polymorphism are still poorly understood. 2. To explore the adaptive significance of the colour polymorphism of P. spumarius, an experiment was conducted in captivity under semi‐natural conditions to measure survival, reproductive success, and duration of egg maturation. 3. It was found that there was higher longevity, a higher number of oviposition events, and a higher number of eggs laid by trilineatus phenotype females than by typicus and marginellus, supporting previous reports of an increase in trilineatus frequency during the season. The duration of egg maturation did not differ among phenotypes. 4. The higher longevity and fertility of the trilineatus phenotype may compensate, for example, the higher rate of attack by parasitoids and/or higher solar radiation reflectance in this phenotype, which have already been reported in previous studies, constituting a possible mechanism for the maintenance of this polymorphism.     

The fitness consequences of honesty: Under‐signalers have a survival advantage in song sparrows

How honest or reliable signaling can evolve and be maintained has been a major question in evolutionary biology. The question is especially puzzling for a particular class of signals used in aggressive interactions: threat signals. Here, we report a study on song sparrows (Melospiza melodia) in which we assayed males with playbacks on their territories to quantify their aggressiveness (flights and close proximity) and aggressive signaling levels (rates of soft song, a close‐range signal reliably predicting attack) and asked whether these traits affect individuals’ survival on territory. We found that the effect of aggressive signaling via soft song interacted with aggressive behaviors such that there was a negative correlational selection: among males with low aggression, those males that signaled at higher levels (over‐signalers) had higher survival whereas among males with high aggression those that signaled at low levels (under‐signalers) survived longer. In other words, males that deviate from reliable signaling have a survival advantage. These results, along with previous research that suggested most of the deviation from reliable signaling in this system is in the form of under‐signaling (high‐aggression males signaling at low levels) pose a puzzle for future research on how this reliable signaling system is maintained.     

Antioxidant response of Chlamydomonas reinhardtii grown under different element regimes

Nutrient stress is one of the most favorable ways of increasing neutral lipid and high value‐added output production by microalgae. However, little is known about the level of the oxidative damage caused by nutrient stress for obtaining an optimal stress level for maximum production of specific molecules. In this study, the antioxidant response of Chlamydomonas reinhardtii grown under element deprivation (nitrogen, sulfur, phosphorus and magnesium) and supplementation (nitrogen and zinc) was investigated. All element regimes caused a decrease in growth, which was most pronounced under N deprivation. Element deprivation and Zn supplementation caused significant increases in H₂O₂ and lipid peroxidation levels of C. reinhardtii. Decrease in total chlorophyll level was followed by an increase of total carotenoid levels in C. reinhardtii under N and S deprivation while both increased under N supplementation. Confocal imaging of live cells revealed dramatic changes of cell shape and production of neutral lipid bodies accompanied by a decrease of chlorophyll clusters. Antioxidant capacity of cells decreased under N, S and P deprivation while it increased under N and Zn supplementation. Fluctuation of antioxidant enzyme activities in C. reinhardtii grown under different element regimes refers to different metabolic sources of reactive oxygen species production triggered by a specific element absence or overabundance.     

Effect of vitamin A pretreatment on Escherichia coli-induced lipid peroxidation and level of 3-nitrotyrosine in kidney of guinea pig

In the present study, we report the effect of vitamin A (Vit A, retinol palpitate) on kidney lipid peroxidation and 3-nitrotyrosine (3-NT) levels induced after Escherichia coli administration to guinea pigs. Vit A was administrated intraperitoneally (i.p.) to guinea pigs at a dose 15,000 IU/kg per day for 7 days prior to E. coli injection. On day 8, the animals were injected i.p. with E. coli dosed at 12 ×10⁹ colony forming units per kilogram. Kidneys were collected 6 h after administration of E. coli. Malondialdehyde (MDA) as a lipid peroxidation product, and 3-NT levels were measured by reverse phase high-performance liquid chromatography. There was a significant increase in MDA and 3-NT levels in lipopolysaccaharide-induced group (p<0.001). 3-NT was not detectable in kidney of normal control animals. However, Vit A administration prior to E. coli injection prevented 3-NT formation but did not prevent the rice in MDA level of kidney (p<0.001). Vit A alone did not alter the MDA level in the kidney of the control group. (Mol Cell Biochem 278: 33–37, 2005)     

The antimicrobial activity of extracts of the lichen Hypogymnia tubulosa and its 3-hydroxyphysodic acid constituent

The antimicrobial activity and the MIC values of the diethyl ether, acetone, chloroform, petroleum ether, and ethanol extracts of the lichen Hypogymnia tubulosa and its 3-hydroxyphysodic acid constituent have been investigated against some microorganisms. At least one of the extracts or 3-hydroxyphysodic acid showed antimicrobial activity against Aeromonas hydrophila, Bacillus cereus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Listeria monocytogenes, Proteus vulgaris, Salmonella typhimurium, Staphylococcus aureus, Streptococcus faecalis, and Candida albicans. No antifungal activity of the extracts has been observed against ten filamentous fungi.     

Glutathione S-Transferase M1, T1, P1 Genotypes and Risk for Development of Colorectal Cancer

The glutathione S-transferase (GST) supergene family is an important part of cellular enzyme defense against endogenous and exogenous chemicals, many of which have carcinogenic potential. The present investigation was conducted to detect a possible association between polymorphisms at the GSTM1, GSTT1, and GSTP1 genes and the interaction with cigarette smoking and colorectal cancer incidence. We examined 181 patients with colorectal cancer and 204 controls. DNA was extracted from whole blood, and the GSTM1, GSTT1, and GSTP1 polymorphisms were determined using a real-time polymerase chain reaction and fluorescence resonance energy transfer with a Light-Cycler instrument. Associations between specific genotypes and the development of colorectal cancer were examined by use of logistic regression analysis to calculate odds ratios (OR) and 95% confidence intervals (CI). The GSTM1 polymorphism was associated with an increased risk of developing colorectal cancer (OR = 1.62, 95% CI: 1.06–2.46). Also the risk of colorectal cancer associated with the GSTT1 null genotype was 1.64 (95% CI: 1.10–2.59). Statistically no differences were found between patients with colorectal cancer and control groups for the GSTP1 Ile/Ile, Ile/Val and Val/Val genotypes. In addition, the frequencies of the GSTM1 and GSTT1 deletion genotypes differed significantly between the cases and controls for current smokers; the GSTT1 null genotype especially is associated with a greater risk of colorectal cancer (OR = 2.44, 95% CI: 1.24–4.81). The GSTM1 and GSTT1 deletions were associated with an increased risk of developing a transverse or rectal tumor (OR = 1.86, 95% CI: 1.15–3.00; OR = 1.70, 95% CI: 1.02–2.84; respectively). The glutathione S-transferase polymorphisms were not associated with risk in patients stratified by age. The risk of colorectal cancer increased as putative high-risk genotypes increased for the combined genotypes of GSTM1 null, GSTT1 null, and either GSTP1 valine heterozygosity or GSTP1 valine homozygosity (OR = 2.69, 95% CI: 1.02–7.11). In conclusion, the results obtained in this study clearly suggest that those susceptibility factors related to different GST polymorphic enzymes are predisposing for colorectal cancer.     

The Effects of Triiodothyronine on Rat Testis: A Morphometric and Immunohistochemical Study

The aim of present study was to investigate the effects of 3,3′,5-triiodothyronine (T₃) on rat testis both morphometrically and immunohistochemically with determining of insulin-like growth factor I (IGF-I) expression. Adult male Wistar-albino rats used in the study were divided into two groups; control and T₃-treated groups. After T₃ treatment there was observed to be a decrease in testicular weights, diameters of seminiferous tubules and the number of sertoli cells, and an increase in the number of leydig cells (P<0.05). Some of the seminiferous tubule lumens of T₃ administrated rats had cellular debris. IGF-I was localized in sertoli cells, late spermatids and leydig cells of all groups. IGF-I immunoreactivity in T₃ treated rats was higher than in controls in all stages of the cycle of rat seminiferous epithelium, but the staining intensity of leydig cells were similar in both groups. In conclusion, the present results suggest that T₃ may modulate the testicular function by affecting IGF-I activity at the gonadal level.