Genetically modified laboratory animals--what welfare problems do they face?

In this article, we respond to public concern expressed about the welfare of genetically modified (GM) nonhuman animals. As a contribution to the debate on this subject, we attempt in this article to determine in what situations the practice of genetic modification in rodents may generate significant welfare problems. After a brief discussion of the principles of animal welfare, we focus on the problem of animal suffering and review some types of gene modifications likely to cause predictable welfare problems. In this article, we also consider suffering that may be involved in the process of generating GM animals. Finally, we discuss the role of GM animals in attempts to reduce, replace, and refine the use of animals in research.     

Functional interaction between PARP-1 and PARP-2 in chromosome stability and embryonic development in mouse

The DNA damage-dependent poly(ADP-ribose) polymerases, PARP-1 and PARP-2, homo- and heterodimerize and are both involved in the base excision repair (BER) pathway. Here, we report that mice carrying a targeted disruption of the PARP-2 gene are sensitive to ionizing radiation. Following alkylating agent treatment, parp-2(-/-)-derived mouse embryonic fibroblasts exhibit increased post-replicative genomic instability, G(2)/M accumulation and chromosome mis-segregation accompanying kinetochore defects. Moreover, parp-1(-/-)parp-2(-/-) double mutant mice are not viable and die at the onset of gastrulation, demonstrating that the expression of both PARP-1 and PARP-2 and/or DNA-dependent poly(ADP-ribosyl) ation is essential during early embryogenesis. Interestingly, specific female embryonic lethality is observed in parp-1(+/-)parp-2(-/-) mutants at E9.5. Meta phase analyses of E8.5 embryonic fibroblasts highlight a specific instability of the X chromosome in those females, but not in males. Together, these results support the notion that PARP-1 and PARP-2 possess both overlapping and non-redundant functions in the maintenance of genomic stability.     

Estrogen decreases the sensitivity of anterior pituitary to the inhibitory effect of nitric oxide on prolactin release

OBJECTIVE: We investigated the effect of chronic estrogen treatment on the inhibitory action of nitric oxide (NO) on prolactin release. METHODS: The effect of NO on prolactin release was studied in anterior pituitaries of female Wistar rats, intact at random stages, ovariectomized (OVX), and OVX treated for 15 days with 17beta-estradiol (OVX-E(2)). RESULTS: Sodium nitroprusside (NP, 0.5 mM), a NO donor, inhibited prolactin release from anterior pituitaries and was able to stimulate cGMP synthesis in intact and OVX rats. Only a high, supraphysiological concentration of NP (2 mM) inhibited prolactin release from anterior pituitaries of OVX-E(2) rats and increased cGMP synthesis in OVX-E(2) rats. 8-Br-cGMP, a cGMP analogue, decreased prolactin release from anterior pituitaries of OVX rats but did not affect it in OVX-E(2) rats. CONCLUSION: Our results suggest that estrogen may modify the sensitivity of the anterior pituitary to the inhibitory effect of NO on prolactin release by affecting guanylyl cyclase activity and the cGMP pathway.     

Photosynthetic UV-B Response of Beech (Fagus sylvatica L.) Saplings

Cloned saplings of beech (7-y-old) were exposed to enhanced UV-B irradiation (+25 %) continuously over three growing seasons (1999–2001). Analysis of CO₂ assimilation, variable chlorophyll (Chl) a fluorescence, and pigment composition was performed in late summer of the third growing season to evaluate the influence of long-term elevated UV-B irradiation. This influence was responsible for the stimulation of the net assimilation rate (P _N) over a range of irradiances. The increase in P _N was partially connected to increase of the area leaf mass, and thus to the increased leaf thickness. Even a higher degree of UV-B induced stimulation was observed at the level of photosystem 2 (PS2) photochemistry as judged from the irradiance response of electron transport rate and photochemical quenching of Chl a. The remarkably low irradiance-induced non-photochemical quenching of maximum Chl a fluorescence (NPQ) in the UV-B plants over the entire range of applied irradiances was attributed both to the reduced demand on non-radiative dissipation processes and to the considerably reduced contribution of the quenching localised in the inactivated PS2 reaction centres. Neither the content of Chls and total carotenoids expressed per leaf area nor the contents of lutein, neoxanthin, and the pool of xanthophyll cycle pigments (VAZ) were affected under the elevated UV-B. However, the contributions of antheraxanthin (A) and zeaxanthin (Z) to the entire VAZ pool in the dark-adapted UV-B treated plants were 1.61 and 2.14 times higher than in control leaves. Surprisingly, the retained A+Z in UV-B treated plants was not accompanied with long-term down-regulation of the PS2 photochemical efficiency, but it facilitated the non-radiative dissipation of excitation energy within light-harvesting complexes (LHC) of PS2. Thus, in the beech leaves the accumulation of A+Z, induced by other factors than excess irradiance itself, supports the resistance of PS2 against combined effects of high irradiance and elevated UV-B.     

Reconstruction of the three-dimensional NMR spectrum of a protein from a set of plane projections

Three-dimensional protein NMR spectra can be obtained significantly faster than by traditional methods by a projection-reconstruction procedure related to X-ray tomography. First, two orthogonal projections are acquired in quick two-dimensional experiments with the evolution parameters t₁ or t₂ set to zero. These projections define a three-dimensional lattice; all cross-peaks must lie on this lattice but not all lattice points are occupied. A third experiment with t₁ and t₂ incremented simultaneously and in a fixed ratio, generates a projection onto a tilted plane and thus establishes the positions of all the cross-peaks unambiguously. This projection-reconstruction technique has been tested on the 500 MHz three-dimensional HNCO spectrum of ubiquitin.     

Type of mycorrhizal associations in two coastal nature reserves of the Mediterranean basin

We analysed the mycorrhizal types of two coastal Mediterranean plant communities. Plants belonging to 82 species of 46 families growing in two Mediterranean study sites located within a Regional Natural Park in Italy (Macchia Lucchese) and in a National Park in Croatia (Brijuni) were assessed for the type of their mycorrhizal associations. Mycorrhizas occurred in 83% and 90% of the plant species surveyed in Macchia Lucchese and in Brijuni, respectively. On the basis of macroscopic and microscopic characteristics, six different mycorrhizal types were found, and their co-occurrence in the same plant community showed the large mycorrhizal diversity in Mediterranean vegetation. Different occurrence patterns of mycorrhizal types have been recognised in diverse habitats within Macchia Lucchese, from sand dune plant communities to sclerophyllous woodland. Mycorrhizal type abundance calculated on a floristic basis was very different from that obtained using a vegetation cover index.