Effects of genetically modified plants on microbial communities and processes in soil

The development and use of genetically modified plants (GMPs) has been a topic of considerable public debate in recent years. GMPs hold great promise for improving agricultural output, but the potential for unwanted effects of GMP use is still not fully understood. The majority of studies addressing potential risks of GMP cultivation have addressed only aboveground effects. However, recent methodological advances in soil microbial ecology have allowed research focus to move underground to try to gain knowledge of GMP-driven effects on the microbial communities and processes in soil that are essential to key terrestrial ecosystem functions. This review gives an overview of the research performed to date on this timely topic, highlighting a number of case studies. Although such research has advanced our understanding of this topic, a number of knowledge gaps still prevent full interpretation of results, as highlighted by the failure of most studies to assign a definitively negative, positive or neutral effect to GMP introduction. Based upon our accumulating, yet incomplete, understanding of soil microbes and processes, we propose a synthesis for the case-by-case study of GMP effects, incorporating assessment of the potential plant/ecosystem interactions, accessible and relevant indicators, and tests for unforeseen effects.     

Effects of an arbuscular mycorrhizal fungus and two plant-parasitic nematodes on<Emphasis Type="Italic"> Musa</Emphasis> genotypes differing in root morphology

In this study, the effect of an arbuscular mycorrhizal fungus (AMF) and two migratory endoparasitic nematodes on Musa plant growth, including the root system, were examined. In addition, the AMF-nematode interaction was studied. Seven Musa genotypes with different root systems were selected. Based on their relative mycorrhizal dependency, two genotypes (Calcutta 4 and Obino l'Ewai) were selected for AMF-nematode interaction studies. The experiments were performed under greenhouse conditions. Mycorrhization with Glomus mosseae resulted in a significantly better plant growth even in the presence of nematodes. The effect of AMF on the root system was genotype-dependent and seemed to be related to the relative mycorrhizal dependency of the genotype. The nematodes also affected the root system, decreasing branching. Nematode population densities were significantly reduced in the presence of AMF, except for Pratylenchus coffeae in Obino l'Ewai. In the root system, it appeared that the decreased branching caused by the nematodes was counterbalanced by the increased branching caused by the AMF.     

Few alterations in clinical pathology and histopathology observed in a CYP2C18&19 humanized mice model

Background

This study was performed to characterize a gene-addition transgenic mouse containing a BAC (bacterial artificial chromosome) clone spanning the human CYP2C18&19 genes (tg-CYP2C18&19).

Methods

Hemizygous tg-CYP2C18&19, 11 week old mice were compared with wild-type littermates to obtain information regarding clinical status, clinical pathology and anatomical pathology. After one week of clinical observations, blood samples were collected, organs weighed, and tissues collected for histopathology.

Results

In males, the tissue weights were lower in tg-CYP2C18&19 than in wild-type mice for brain (p ≤ 0.05), adrenal glands (p ≤ 0.05) and brown fat deposits (p ≤ 0.001) while the heart weight was higher (p ≤ 0.001). In female tg-CYP2C18&19, the tissue weights were lower for brain (p ≤ 0.001) and spleen (p ≤ 0.001) compared to wild-type females. Male tg-CYP2C18&19 had increased blood glucose levels (p ≤ 0.01) while females had decreased blood triglyceride levels (p ≤ 0.01).

Conclusion

Despite the observed alterations, tg-CYP2C18&19 did not show any macroscopic or microscopic pathology at the examined age. Hence, these hemizygous transgenic mice were considered to be viable and healthy animals.     

Cono- and seminiphagous insects of Abies alba Mill. in the Gorce National Park in Poland during 1996?–?1998

A study was conducted on the insects infesting seeds and cones of Abies alba Mill. in the Gorce National Park, in southern Poland during 1996–1998. A total of 856 cones were collected from 66 trees growing at 11 sites located in partially or strictly protected forest reserves. Of this sample, 217 cones with 54,958 seeds were dissected. This study yielded 5,816 specimens of insects, namely: seminiphagous Resseliella piceae Seitn., Megastigmus suspectus Borr. as well as conophagous Earomyia impossibile Morge, Barbara herrichiana Obr. and Dioryctria abietella (Den. et Schiff.). The most abundant species was R. piceae with 4,186 individuals. The index of cone infestation was calculated. It showed great variability between forest reserves and study-years. The numbers of insect individuals, numbers of viable and infertile seeds, and seeds damaged by M. suspectus and R. piceae, in both strict and partial reserves in the consecutive years were compared statistically. The test of significant differences between two frequencies at 0.05 level was used in statistical analysis. In both strict and partial reserves, statistically significant differences were found between studied variables.     

Studies on insects and mites causing galls on the leaves of purple willow Salix purpurea L. in the Ojców National Park in Poland

Analytical studies were conducted on the species composition of galls occurring on the leaves of Salix purpurea L. in the Ojców National Park in 1999–2000. The species composition of galls was identical in two consecutive years. Galls were caused by 5species (a total of 480galls). The most numerous species in both years was Pontania viminalis (L.). Index of occurrence frequency and Agrell's index of species co-existence have been calculated. This index reached the highest values in case of Pontania dolichura (Thoms.) and P. viminalis (L.) in 1999 as well as Phyllocolpa leucaspis (Tischb.) and P. viminalis (L.) in 2000.     

Corneal endothelium of the Magellanic penguin (Spheniscus magellanicus) by scanning electron microscopy.

The corneal endothelium is essential for the maintenance of the corneal transparency. The aim of this study was to examine the morphology of the endothelial surface and perform morphometric analysis of the normal corneal endothelial cells of the Magellanic penguin (Spheniscus magellanicus) using scanning electron microscopy. The present work demonstrates that the corneal endothelium of the Magellanic penguin is similar to those described in other vertebrates.     

Regulation by gonadal steroids of estrogen and progesterone receptors along the reproductive tract in female lambs.

The regulation of estrogen and progesterone receptor (ER, PR) expression by estradiol (E2) and progesterone (P4) in the oviduct, uterus and cervix of female lambs was studied. The animals received three intramuscular injections of E2, P4 or vehicle with an interval of 24 h and they were slaugthered 24 h after the third injection. Determinations of ER and PR were performed by binding assays and mRNAs of ER alpha and PR by solution hybridization. High levels of ER and PR in both cervix and oviduct were found in the female lamb, differing from other mammalian species. No significant effects by either E2 or P4 treatment on ER and PR levels in the cervix and oviduct could be observed. E2 treatment increased the mRNA levels of ERa and PR more than 3-fold in the cervix, while P4 treatment increased the mRNA levels of ERa and PR in the uterus. The results show differential effects of gonadal steroids on sex steroid receptor expression along the reproductive tract in female lambs, suggesting that steroid target tissues can modulate responses to the same circulating levels of steroid hormones.     

CO2-stunning of swine for slaughter from the anesthesiological viewpoint

For investigations of CO2-stunning of feeder- and slaughter-pigs parameters of behaviour, blood-gas-analyses and electroencephalograms were chosen. The following results were obtained: 1. Blood-gas-analyses proved that the CO2-stunning does not produce unconsciousness due to a lack of oxygen. 2. The criterias of general anaesthesia: unconsciousness, muscle-relaxation and analgesia with total reversibility could be confirmed. 3. The violent convulsive symptoms were evaluated as reactions identical with the stage II of GUEDEL's scheme of anaesthesia. 4. Muscular agitation, which sometimes appeared a few seconds before the stage of excitation, was judged to belong either to the start of the excitation phase or to the end of Guedel's stage of analgesia, during which the sensitivity is decreased. Neither study of behavior nor objective measurements showed, during the first 10 to 20 seconds of exposure to the CO2, any sign of pain or suffering related to the Act for Prevention of Cruelty to Animals, and accordingly such suffering should not be ascribed to the CO2 stunning method.