Alterations of the WNT7A Gene in Clear Cell Renal Cell Carcinomas

WNT7A (wingless-type MMTV integration site family, member 7A) is a known tumor suppressor gene of non-small cell lung carcinomas (NSCLC) and is frequently inactivated due to CpG-island hypermethylation in human cancers. The members of WNT family are involved in cell signaling and play crucial roles in cancer development. In the present work hypermethylation of the WNT7A gene was detected in 66% (29/44) of analyzed clear cell renal cell carcinomas (RCCs) using methyl-specific PCR (MSP). Moreover, bisulfite sequencing confirmed intensive hypermethylation of the 5′-CpG island of the WNT7A gene. Methylation analysis revealed positive correlations between tumor stage, Fuhrman nuclear grade and WNT7A hypermethylation. Additionally, restoration of WNT7A gene expression in the A498 cell line by 5-aza-2′-deoxycytidine treatment confirmed a direct contribution of hypermethylation in silencing of the WNT7A gene. High frequency of loss of heterozygosity (LOH) was demonstrated on chromosome 3p25 in regions surrounding the WNT7A gene. The frequent down-regulation of WNT7A gene expression was detected in 88% (15/17) of clear cell RCCs. We have also shown that the WNT7A gene possesses tumor suppression function by colony-formation and cell proliferation assays in RCC cell lines. In summary, the WNT7A gene is inactivated by genetic/epigenetic alterations in clear cell RCC and demonstrates tumor suppressor properties.     

Frequency and types of spontaneous Hprt lymphocyte mutations in Pms2-deficient mice

Deficiencies in DNA mismatch repair (MMR) result in predisposition to neoplasia in both rodents and humans. Pms2 is one of the several proteins involved in the eukaryotic MMR system. In order to determine the effect of Pms2-deficiency on mutation, we measured mutant frequencies in the endogenous Hprt gene of lymphocytes from male Pms2(-/-), Pms2(+/-), and Pms2(+/+) mice. Spleens were removed from mice of various ages and lymphocytes isolated from spleens were cultured to determine the frequency of 6-thioguanine-resistant mutants. Mean mutant frequencies in Pms2(-/-) mice at 6, 10, 18, and 34 weeks of age [42.6 x 10(-6) (n=6), 38.5 x 10(-6) (n=6), 58.2 x 10(-6) (n=9), and 49.1 x 10(-6) (n=5), respectively] were significantly higher than those of comparably aged Pms2(+/+) and Pms2(+/-) mice (all less than 3 x 10(-6)). Mutant clones from the mice were expanded, RNA extracted, and Hprt cDNA amplified by RT-PCR. DNA sequencing analysis of 221 mutant cDNAs from the three different Pms2 genotypes identified 182 clones with independent mutations, including five clones that contained multiple mutations. When compared to the mutational spectrum observed in Pms2(+/+) and Pms2(+/-) mice, the mutational spectrum for Pms2(-/-) mice was significantly different. The Pms2(-/-) mutational analysis indicated that loss of the Pms2 protein causes increases in the frequencies of strand-slippage-type frameshift mutations and of A:T --> G:C transitions in the Hprt gene. The absolute frequencies of A:T --> G:C transitions in MMR-deficient mice suggest increases in this mutation may be a common feature of MMR-deficient mice, not just of Pms2-deficient mice, and may be related to the cancer predisposition that results from loss of MMR function.     

Increased pulmonary vascular resistance and defective pulmonary artery filling in caveolin-1-/- mice

Caveolin-1, the structural and signaling protein of caveolae, is an important negative regulator of endothelial nitric oxide synthase (eNOS). We observed that mice lacking caveolin-1 (Cav1(-/-)) had twofold increased plasma NO levels but developed pulmonary hypertension. We measured pulmonary vascular resistance (PVR) and assessed alterations in small pulmonary arteries to determine the basis of the hypertension. PVR was 46% greater in Cav1(-/-) mice than wild-type (WT), and increased PVR in Cav1(-/-) mice was attributed to precapillary sites. Treatment with NG-nitro-l-arginine methyl ester (l-NAME) to inhibit NOS activity raised PVR by 42% in WT but 82% in Cav1(-/-) mice, indicating greater NO-mediated pulmonary vasodilation in Cav1(-/-) mice compared with WT. Pulmonary vasculature of Cav1(-/-) mice was also less reactive to the vasoconstrictor thromboxane A2 mimetic (U-46619) compared with WT. We observed redistribution of type I collagen and expression of smooth muscle alpha-actin in lung parenchyma of Cav1(-/-) mice compared with WT suggestive of vascular remodeling. Fluorescent agarose casting also showed markedly decreased density of pulmonary arteries and artery filling defects in Cav1(-/-) mice. Scanning electron microscopy showed severely distorted and tortuous pulmonary precapillary vessels. Thus caveolin-1 null mice have elevated PVR that is attributed to remodeling of pulmonary precapillary vessels. The elevated basal plasma NO level in Cav1(-/-) mice compensates partly for the vascular structural abnormalities by promoting pulmonary vasodilation.     

Larvae of Ceratocanthidae and Hybosoridae (Coleoptera: Scarabaeoidea): study of morphology, phylogenetic analysis and evidence of paraphyly of Hybosoridae

Abstract. Larvae of the scarabaeoid genera Germarostes Paulian, Cyphopisthes Gestro, Paulianostes Ballerio, Ceratocanthus White, Pterorthochaetes Gestro, Madrasostes Paulian, Astaenomoechus Martínez & Pereira (Ceratocanthidae) and Hybosorus Macleay, Phaeochrous Castelnau, and Anaides Westwood (Hybosoridae) are described, keyed and illustrated with fifty‐seven drawings. A phylogenetic analysis of these two families based on larval morphology is presented. Fifty‐four larval morphological and three biological characters from twenty‐seven taxa revealed nineteen equally parsimonious cladograms. The monophyly of (Ceratocanthidae + Hybosoridae) is supported by four unambiguous unique synapomorphies: dorsal medial endocarina on cranium extended anteriorly into frontal sclerite; presence of large membranous spot on apical antennomere; labium dorsally with four pores in centre (secondarily reduced to two pores in some groups); and presence of stridulatory organ on fore‐ and middle legs (secondarily reduced in some groups). Our analysis suggests that the family Hybosoridae is paraphyletic with respect to Ceratocanthidae. The clade comprising the hybosorid genera Hybosorus and Phaeochrous is the sister group of the remaining Hybosoridae plus Ceratocanthidae. It is supported by two unambiguous synapomorphies: two apical antennomeres completely joined and the stridulatory organ represented by seven to nine large teeth anteriorly on the middle leg. The hybosorid genus Anaides is a sister group to the remaining Hybosoridae plus Ceratocanthidae (without Hybosorus and Phaeochrous) and the ceratocanthid genus Germarostes is a sister group to the remaining Hybosoridae plus Ceratocanthidae (without Hybosorus, Phaeochrous and Anaides). The ceratocanthid genera Cyphopisthes, Astaenomoechus, Paulianostes, Pterorthochaetes, and Madrasostes constitute a sister group to the hybosorid genus Cryptogenius and are supported by the presence of two reversions: two dorsal pores on labium and completely reduced stridulatory organs on fore‐ and middle legs.     

Structural–Functional Units of Epidermis

The available data suggest that epidermis is organized as a system of discrete structural–functional units (SFUs) that reproduce both in vivo and in vitro. SFUs are formed in the culture of epidermal keratinocytes via self-organization of the developing cellular elements. SFUs are capable of self-maintenance and form a niche for stem cells. At the same time, due to the maintenance of asymmetric proliferation kinetics of the stem cells, SFUs serve as a barrier to their uncontrolled replication.     

Red fox takeover of arctic fox breeding den: an observation from Yamal Peninsula, Russia

Here, we report from the first direct observation of a red fox (Vulpes vulpes) intrusion on an arctic fox (Vulpes lagopus) breeding den from the southern Arctic tundra of Yamal Peninsula, Russia in 2007. At the same time, as a current range retraction of the original inhabitant of the circumpolar tundra zone the arctic fox is going on, the red fox is expanding their range from the south into arctic habitats. Thus, within large parts of the northern tundra areas the two species are sympatric which gives opportunities for direct interactions including interference competition. However, direct first-hand observations of such interactions are rare, especially in the Russian Arctic. In the present study, we observed one red fox taking over an arctic fox breeding den which resulted in den abandonment by the arctic fox. On July 19, eight arctic fox pups were observed on the den before the red fox was observed on the same den July 22. The pups were never seen at the den or elsewhere after the red fox was observed on the den for as long as we stayed in the area (until August 10). Our observation supports the view that direct interference with red fox on breeding dens may contribute to the range retraction of arctic foxes from the southern limits of the Arctic tundra in Russia.