Familial porphyria cutanea tarda: hybridization analysis of the uroporphyrinogen decarboxylase locus

Familial porphyria cutanea tarda (PCT) results from a deficiency of uroporphyrinogen decarboxylase (URO-D) activity. Hybridization analysis of genomic DNA from unrelated normal individuals and PCT pedigree members failed to detect any major deletions, rearrangements or restriction fragment length polymorphisms at the URO-D locus.     

Cytogenetics of the European plethodontid salamanders of the genus Hydromantes (Amphibia,Urodela)

A karyological analysis was carried out on different European species of the genus Hydromantes (Plethodontidae). All the species examined share the same chromosome number (2n=28) and, with the exception represented by pair XIV, morphologically similar karyotypes. While the karyotypes display a similar distribution — mainly centromeric and pericentric — of C-heterochromatin, quantitative variations in pericentric heterochromatin are observed among species. In the continental species Hydromantes italicus and ambrosii as well as in the eastern Sardinian species imperialis, flavus and specie nova, pair XIV consists of heteromorphic sex chromosomes of the XX/XY type. It is proposed that the differentiation of the Y might have taken place through the occurrence of a structural rearrangement, such as a pericentric inversion, starting from a hypothetical, homomorphic pair XIV. A sex-related heteromorphism is not found in the western Sardinian species H. genei. A further karyological differentiation among these species concerns the position of the nucleolus organizing region (NOR), which is located on chromosome XII (H. italicus and ambrosii) or on chromosome X, close to the centromere (H. genei, H. imperialis and H. specie nova), or in an intercalary position (H. flavus). The location and the number of the 5 S DNA sites have been conserved during species divergence. On the basis of these karyological data, as well as of results obtained through a preliminary restriction enzyme analysis of the ribosomal and genomic DNAs, the phyletic relationships among the European Hydromantes species are discussed.     

Influence of imidazole on behavioral effects induced by dopaminergic agonists in rats

Imidazole (IMI) (from 18.7 to 300 mg/Kg) i.p. injected in adult rats induced shaking, which was antagonized by both morphine (MOR) and haloperidol (HALO) but not by methysergide (MET). I.p. IMI pretreatment inhibited the penile erections (PE) and stretching and yawning (SY) typically elicited by N-n-propylnorapomorphine (NPA), a well-known CNS dopamine (DA) receptor stimulant, injected either i.p. or i.c.v., whereas it enhanced stereotyped behavior (SB). IMI had similar effects on the same parameters considered when injected before lisuride, an ergot derivative also active as a central DA receptor agonist. In this case not only SB but also and above all aggressiveness were markedly potentiated, both the signs appearing at doses of lisuride which were "per se" ineffective. Aggressiveness, like SB, was not sex linked and was antagonized by HALO and MOR, but not by MET. IMI alone potentiated the fighting induced by electrical shock, an effect which was abolished by HALO pretreatment. Considering the results obtained as a whole it is submitted that IMI antagonizes PE and SY through a selective blockade of a class of DA receptors, presumably DA presynaptic autoinhibitors, thus potentiating SB and aggressiveness, which involve stimulation of DA postsynaptic receptors.     

Vascularized periosteum associated with cancellous bone graft: an experimental study

The association of a vascularized periosteal flap with a cancellous bone graft was studied on a group of 20 Wistar rats. Ten rats were sacrificed at 6 weeks and seven at 12 weeks (three died prematurely). The behavior of the cancellous bone graft buried in striated muscle and the osteogenic capacity of a simple vascularized periosteal flap also were observed on the same animals. Results of the study are as follows: In 14 of 17 animals, a vascularized periosteal flap wrapped around a cancellous bone graft resulted in new cortical bone formation with little resorption of the initial cancellous graft. A vascularized musculoperiosteal flap has produced a small amount of new compact bone only in 4 of 17 animals. A cancellous bone graft buried into well-vascularized muscle tissue was resorbed (15 cases) or necrotic (2 cases) at 12 weeks. In conclusion, the association of a vascularized periosteal flap and cancellous bone is a better means to produce compact bone than a vascularized periosteal flap alone or an isolated cancellous bone graft.     

Effects of shell status and social context on the agonistic behavior of the tropical hermit crab,Clibanarius signatus

In the hermit crabClibanarius signatus, the influence of both shell status and social context on agonistic behavior was examined. The experimental hermits were of the same size and sex, but differed in the status of the inhabited shell, which was either optimal, sub-optimal or damaged. The evidence from this experiment suggests that the agonistic behavior ofC. signatus is influenced to a great extent by asymmetries in the resource value; attacks are mainly performed by crabs which inhabit shells in a relatively poor condition and are mostly directed towards opponents with better-fitting shells. However, this effect differs according to the social context, being more pronounced when the potential gain is greater. Shell fights are decidedly more complex than most animal combats; more work is certainly needed to understand the mechanisms underlying resource assessment and decisions made during hermit crabs' interactions.     

Physical Map of the Malaria Vector Anopheles Gambiae

Random cDNA clones, cosmid clones and RAPD polymorphic fragments have been localized by in situ hybridization to the ovarian nurse cell polytene chromosomes of the malaria vector Anopheles gambiae. We thus established 85 molecular markers for 110 sites within the whole A. gambiae polytene chromosome complement. The cDNA clones analyzed were isolated at random, and their exact localizations were determined by in situ hybridization. For 15 of the cDNA clones, a partial nucleotide sequence has been obtained; for nine of them sequence searches in the GenBank database revealed high degrees of similarity with published sequences. The cosmid clones analyzed were obtained as the result of screening with a few of the aforementioned cDNA clones of particular interest, or taken from a small set of randomly isolated cosmid clones. The RAPD clones are polymorphic fragments, potentially diagnostic for the various chromosomal forms of A. gambiae that are currently being analyzed.     

Chlorsulfuron resistance in Daucus carota cell lines and plants:Involvement of gene amplification

Daucus carota L. cell lines stably resistant to the herbicide chlorsulfuron (CS) have been isolated according to a stepwise selection. Studies carried out during different selection steps show that the specific activity of the target enzyme acetohydroxyacid synthase (AHAS) increases along with CS resistance. Southern hybridization analysis performed with aBrassica napus AHAS probe in a CS highly-resistant cell line reveals the presence of a greatly amplifiedEcoRI fragment of genomic DNA. This indicates that AHAS overproduction induced by stepwise selection is due to gene amplification. Regenerants from some resistant cell lines maintained the CS-resistant trait at the whole plant level.     

The nitrite reductase gene of Pseudomonas aeruginosa: Effect of growth conditions on the expression and construction of a mutant by gene disruption

Abstract The expression of nitrite reductase has been tested in a wild-type strain of Pseudomonas aeruginosa (Pao1) as a function of nitrate concentration under anaerobic and aerobic conditions. Very low levels of basal expression are shown under non-denitrifying conditions (i.e. absence of nitrate, in both aerobic and anaerobic conditions); anaerobiosis is not required for high levels of enzyme production in the presence of nitrate. A Pseudomonas aeruginosa strain, mutated in the nitrite reductase gene, has been obtained by gene replacement. This mutant, the first of this species described up to now, is unable to grow under anaerobic conditions in the presence of nitrate. The anaerobic growth can be restored by complementation with the wild-type gene.     

PYK2 is overexpressed in chronic lymphocytic leukaemia: A potential new therapeutic target

Chronic Lymphocytic Leukaemia (CLL) is the most common adult B-cell leukaemia and despite improvement in patients' outcome, following the use of targeted therapies, it remains incurable. CLL supportive microenvironment plays a key role in both CLL progression and drug resistance through signals that can be sensed by the main components of the focal adhesion complex, such as FAK and PYK2 kinases. Dysregulations of both kinases have been observed in several metastatic cancers, but their role in haematological malignancies is still poorly defined. We characterized FAK and PYK2 expression and observed that PYK2 expression is higher in leukaemic B cells and its overexpression significantly correlates with their malignant transformation. When targeting both FAK and PYK2 with the specific inhibitor defactinib, we observed a dose–response effect on CLL cells viability and survival. In vivo treatment of a CLL mouse model showed a decrease of the leukaemic clone in all the lymphoid organs along with a significant reduction of macrophages and of the spleen weight and size. Our results first define a possible prognostic value for PYK2 in CLL, and show that both FAK and PYK2 might become putative targets for both CLL and its microenvironment (e.g. macrophages), thus paving the way to an innovative therapeutic strategy.     

Hatching plasticity in a Southeast Asian tree frog mitigates submergence-induced mortality

Environmentally cued hatching has been well-documented in amphibians in response to a wide range of abiotic and biotic factors. The hatching of terrestrial amphibian eggs in response to flooding may be basal within the group, but amphibian lineages in tropical Asia and sub-Saharan Africa have not received as much attention as their Neotropical counterparts. We investigated submergence-induced hatching in Feihyla hansenae, a Rhacophorid tree frog with terrestrial eggs. We quantified natural rates of clutch submergence at our study site in Thailand. Using submergence experiments, we found that embryos are capable of hatching early to escape flooding, and that failure to hatch results in mortality. Among the embryos that were able to hatch early, only the earliest, youngest hatchlings experienced a trade-off in body size that persisted for 6 days, while later, older hatchlings were not significantly smaller than spontaneous hatchlings under control conditions. By incorporating our natural and experimental data into Monte Carlo methods to simulate and compare survival probabilities with and without hatching plasticity, we found an overall 3.1% increase in submergence survival due to hatching plasticity. Our findings support the idea that flooding-induced hatching is widespread across amphibians with terrestrial eggs and highlight the importance of researching understudied tropical regions. As climate change is projected to affect rainfall patterns, the ability of embryos to escape abiotic egg-stage threats may be an indicator of species' ability to flexibly navigate a changing environment.