Cutaneous application of α-methylspermidine activates the growth of resting hair follicles in mice

Recent studies using transgenic animals have revealed a crucial role for polyamines in the development and the growth of skin and hair follicles. In mammals, the growth of hair is characterized by three main cyclic phases of transformation, including a rapid growth phase (anagen), an apoptosis-driven regression phase (catagen) and a relatively quiescent resting phase (telogen). The polyamine pool during the anagen phase is higher than in telogen and catagen phases. In this study, we used α-methylspermidine, a metabolically stable polyamine analog, to artificially elevate the polyamine pool during telogen. This manipulation was sufficient to induce hair growth in telogen phase mice after 2 weeks of daily topical application. The application site was characterized by typical features of anagen, such as pigmentation, growing hair follicles, proliferation of follicular keratinocytes and upregulation of β-catenin. The analog penetrated the protective epidermal layer of the skin and could be detected in dermis. The natural polyamines were partially replaced by the analog in the application site. However, the combined pool of natural spermidine and α-methylspermidine exceeded the physiological spermidine pool in telogen phase skin. These results highlight the role of polyamines in hair cycle regulation and show that it is possible to control the process of hair growth using physiologically stable polyamine analogs.     

Ural owl sex allocation and parental investment under poor food conditions

Parents are expected to overproduce the less costly sex under poor food conditions. The previously regular 3-year cycle in the abundance of voles, the main prey of the Ural owl, Strix uralensis, temporarily disappeared in 1999–2001. We studied Ural owls' parental feeding investment and sex allocation during these poor-quality years. We sexed hatchlings and embryos in unhatched eggs of all 131 broods produced during these years. Population wide, the owls produced significantly more males (56%). The parental food investment in the brood was estimated by sorting out the prey remains in the bottom of nest boxes. Food delivered to 83 broods without chick mortality showed no clear sex-specific investment. Nestling mortality was equal in both sexes. Thus, evidence for an investment-driven sex allocation is weak. Neither laying date, brood size nor the female's condition correlated with offspring sex ratios. In these poor years, parents provided less food per chick and the fledging weight of daughters was reduced more than the weight of sons compared with years of high food abundance (1983 and 1986). We discuss, in relation to published studies, the possibility of a sex-allocation scenario where, under poor food conditions, a daughter's long-term fitness is reduced more than a son's.     

Animal disease models generated by genetic engineering of polyamine metabolism

The polyamines putrescine, spermidine and spermine are natural components of all living cells. Although their exact cellular functions are still largely unknown, a constant supply of these compounds is required for mammalian cell proliferation to occur. Studies with animals displaying genetically altered polyamine metabolism have shown that polyamines are intimately involved in the development of diverse tumors, putrescine apparently has specific role in skin physiology and neuroprotection and the higher polyamines spermidine and spermine are required for the maintenance of pancreatic integrity and liver regeneration. In the absence of ongoing polyamine biosynthesis, murine embryogenesis does not proceed beyond the blastocyst stage. The last years have also witnessed the appearance of the first reports linking genetically altered polyamine metabolism to human diseases.     

Gastric Pit Cell Hyperplasia and Glandular Atrophy in Carbonic Anhydrase IX Knockout Mice: Studies on Two Strains C57/BL6 and BALB/C

Carbonic anhydrase (CA) isoenzyme IX is a hypoxia-inducible enzyme, which is expressed in the human and rodent gastrointestinal tract and overexpressed in several different tumors. Functionally, it has probably an effect on proliferation and differentiation of gastrointestinal epithelial cells. It may also participate in gastric morphogenesis, since a recent study has shown gastric pit cell hyperplasia and glandular atrophy in CA IX-knockout mice. However, it is not known whether CA IX produces morphological changes in the gastric mucosa, which can turn into a dysplasia or malignancy in the presence of some carcinogenic factors. High-salt diet is considered such a factor which has been shown to modulate Helicobacter pylori-associated carcinogenesis. We produced two strains of CA IX-knockout mice, C57/BL6 and BALB/c, and the mice ate either standard or high-salt feed for 20 weeks. Stomach samples were collected from 40 Car9^−/− knockout mice and 37 wildtype littermates, and the tissue sections were examined for histology. CA IX-deficiency caused gastric pit cell hyperplasia and glandular atrophy in both BALB/c and C57/BL6 strains. Excess dietary salt had no significant effect on the severity of pit cell hyperplasia. No dysplasia was found in any of the groups. In C57/BL6 mice, CA IX-deficiency was associated with gastric submucosal inflammation. The results indicate that CA IX-deficiency provides a useful model to study the mechanisms of gastric morphogenesis and epithelial integrity. Further studies are needed to see whether CA IX has a role in the regulation of immune response. The findings suggest that although CA IX-deficiency is not a tumor-promoting factor per se, it induces glandular atrophy in the body mucosa, a lesion which is considered to be a preneoplastic alteration in the stomach.     

Genetic structure of an endangered raptor at individual and population levels

The Finnish population of White-tailed Eagle (Haliaeetus albicilla) has gone through two major demographic bottlenecks during the last two centuries. Strong conservation measures have allowed the population to recover, but despite the rapid population growth during recent years the species is still classified as endangered. We studied the genetic population structure at both individual and population levels in an attempt to recognize the processes shaping it. We used 9 microsatellite loci and 473 base pair fragment of the mitochondrial DNA control region on samples collected between the years 2003 and 2007 (N = 489). We found a clear isolation by distance pattern at fine scale (i.e. individual level) which is most likely a result of species’ philopatric behaviour. Although we did not find signs of the recent bottlenecks, we did find evidence of an ancient bottleneck that has occurred most likely over 21,000 years ago, long before the genetic divergence of the two present Finnish subpopulations (one along the Baltic Sea coast line and another in Lapland and easternmost Finland). We conclude that the present population structure is mainly a consequence of the species philopatric behaviour over a long time period instead of recent population bottlenecks. Based on our results, the Finnish population seems to have ongoing immigration from neighbouring populations. Hence, even though the population has recovered mainly through local growth, our results suggest that gene flow from genetically differentiated populations have had an impact as well.     

Antrodia hyalina, a new polypore from Russia, and A. leucaena, new to Europe

A new polypore species, Antrodia hyalina, is described from Russia. It is morphologically similar to Antrodia pulvinascens, but differs in having annual, thinner and softer basidiocarps, solid skeletal hyphae, and cylindrical spores. Antrodia leucaena, originally described from China, is reported as new from Finland and Russia on Populus tremula. Antrodia wangii is regarded as a synonym of A. bondartsevae.