Expression of the yeast cpd1 gene in tobacco confers resistance to the fungal toxin cercosporin

Many phytopathogenic species of the fungus Cercospora produce cercosporin, a photoactivated perylenequinone toxin that belongs to a family of photosensitizers, which absorb light energy and produce extremely cytotoxic, reactive oxygen species. The cpd1 (cercosporin photosensitizer detoxification) gene of yeast (Saccharomyces cerevisiae), which encodes for a novel protein with significant similarity to the FAD-dependent pyridine nucleotide reductases, confers resistance to cercosporin when over-expressed in yeast. The aim of this work was to investigate the potential ability of cpd1 gene to confer resistance to cercosporin when expressed in tobacco plants (Nicotiana tabacum). Transgenic tobacco plants were produced using Agrobacterium tumefaciens, with cpd1 integrated as the gene of interest. We report here that expression of cpd1 gene in tobacco can mediate resistance to cercosporin. The involvement of cpd1 gene in the detoxification of the cercosporin reinforces previous observations, which suggested that resistance to cercosporin is mediated by a mechanism involving toxin reduction.     

Genetic variation in Myzus persicae populations associated with host-plant and life cycle category

Random amplified polymorphic DNA (RAPD) analysis was applied on 96 clones of Myzus persicae (Sulzer) (Homoptera: Aphididae) representing seven populations collected from different host-plants and regions of Greece. Ten decamer random primers were used to evaluate genetic variation among the examined samples. Despite the variability found between clones, no specific RAPD marker was detected to discriminate the different populations. A significant finding was that aphids from peach and pepper, which were collected far away from tobacco-growing regions, especially those from peach, showed genetic divergence from the tobacco-feeding clones. Moreover, data analysis revealed a significant genetic divergence between holocyclic and anholocyclic populations from tobacco. Lastly, holocyclic clones showed higher level of estimated heterozygosity than the nonholocyclic (anholocyclic, androcyclic and intermediate) ones.     

International study on Artemia XLIX. Salinity effects on survival,maturity, growth,biometrics, reproductive and lifespan characteristics of a bisexual and a parthenogenetic population of Artemia

Two Artemia populations, a bisexual from San Francisco Bay (California, USA) and a parthenogenetic from Tanggu area (Tianjin province, People's Republic of China) are assayed for their tolerance and fitness in various salinity levels. This study was carried out under laboratory conditions where salinity effects upon special characteristics of the two Artemia populations, such as survival, growth rate, maturation, morphology, fecundity and life duration, were recorded. This evaluation revealed that the two populations examined exhibits significant differences in their response against elevated salinity levels. Furthermore, specific biometric parameters can be a useful tool for the discrimination and/or determination of their distribution in a mixed population, which, in fact, is the case in Tanggu salt works. Artemia franciscana seems to be a more effective colonizer at higher salinities. The data presented in this study may generate useful suggestions for proper management of the solar saltworks at Tanggu although further experimentation is needed.International interdisciplinary study on Artemia populations coordinated by the Laboratory of Aquaculture & Artemia Reference Center, University of Ghent, Belgium.     

A differential requirement for SUMOylation in proliferating and non-proliferating cells during Drosophila development

SUMOylation is a highly conserved post-translational modification shown to modulate target protein activity in a wide variety of cellular processes. Although the requirement for SUMO modification of specific substrates has received significant attention in vivo and in vitro, the developmental requirements for SUMOylation at the cell and tissue level remain poorly understood. Here, we show that in Drosophila melanogaster, both heterodimeric components of the SUMO E1-activating enzyme are zygotically required for mitotic progression but are dispensable for cell viability, homeostasis and DNA synthesis in non-dividing cells. Explaining the lack of more pleiotropic effects following a global block of SUMO conjugation, we further demonstrate that low levels of global substrate SUMOylation are detected in mutants lacking either or both E1 subunits. These results not only suggest that minimal SUMOylation persists in the absence of Aos1/Uba2, but also show that the process of cell division is selectively sensitive to reductions in global SUMOylation. Supporting this view, knockdown of SUMO or its E1 and E2 enzymes robustly disrupts proliferating cells in the developing eye, without any detectable effects on the development or differentiation of neighboring post-mitotic cells.     

Leptothoe,a new genus of marine cyanobacteria (Synechococcales) and three new species associated with sponges from the Aegean Sea

Cyanobacterial diversity associated with sponges remains underestimated, though it is of great scientific interest in order to understand the ecology and evolutionary history of the symbiotic relationships between the two groups. Of the filamentous cyanobacteria, the genus Leptolyngbya is the most frequently found in association with sponges as well as the largest and obviously polyphyletic group. In this study, five Leptolyngbya‐like sponge‐associated isolates were investigated using a combination of molecular, chemical, and morphological approach and revealed a novel marine genus herein designated Leptothoe gen. nov. In addition, three new species of Leptothoe, Le. sithoniana, Le. kymatousa, and Le. spongobia, are described based on a suite of distinct characters compared to other marine Leptolyngbyaceae species/strains. The three new species, hosted by four sponge species, showed different degrees of host specificity. Leptothoe sithoniana and Le. kymatousa hosted by the sponges Petrosia ficiformis and Chondrilla nucula, respectively, seem to be more specialized than Le. spongobia, which was hosted by the sponges Dysidea avara and Acanthella acuta. All three species contained nitrogen‐fixing genes and may contribute to the nitrogen budget of sponges. Leptothoe spongobia TAU‐MAC 1115 isolated from Acanthella acuta was shown to produce microcystin‐RR indicating that microcystin production among marine cyanobacteria could be more widespread than previously determined.     

Ecotypic variation in plant characteristics for Origanum vulgare subsp. hirtum populations

Origanum vulgare L. subsp. hirtum (Link) Ietsw. is a polymorphic taxon with respect to essential oil production and glandular trichome density. Here it is examined whether the natural populations that are indigenous in continental Greece may be considered as different ecotypes (i.e. populations with different genetic variation) and whether evidence regarding a fitness cost from essential oil production could be obtained. Samples from 30 different natural populations, differing in climatic conditions, were collected across continental Greece in 1998–2000 and were studied for essential oil production and glandular trichome density. Additionally, individual plants, derived from propagated rhizomes, originated from the natural populations, were transplanted in pots in two gardens that varied in terms of mean temperature and aridity. In these experimental populations, the above-ground phytomass and ratio of leaves and inflorescences to above-ground phytomass were additionally measured. The main findings of the study were (a) a strong positive correlation between essential oil concentration and glandular trichome density, (b) a high positive correlation between natural and experimental populations in essential oil concentration (or glandular trichome density), (c) a negative correlation between essential oil concentration and phytomass and (d) a positive relationship between the essential oil concentration and the factors thermal status and summer drought of the location of origin. Results suggest that the examined populations of O. vulgare subsp. hirtum are different ecotypes, the production of essential oils has a cost to plant growth and that the prime target of selection, by producing these oils, is to increase the resistance to drought and heat stresses.     

Mikroplastik – ein unsichtbarer Störenfried

Microplastic – a hidden harass Plastic is produced in large amounts and used for various purposes. After use, huge amounts end up in the enviroment, often in the oceans. There, fragmentation leads to small particles, called microplastics. By filtrating and benthos‐feeding organisms it can be inadvertently taken up as food. We demonstrate that the unicellular ciliate Paramecium, the freshwater flea Daphnia and the blue mussel Mytilus took up microplastic particles. Even more, in Mytilus, the plastic particles were transported into the digestive gland and accumulated in the respective cells. Subsequently, pathological alterations in the gland were noted. Microplastics are of concern because animals might starve with a full belly after uptaking large amounts of microplastics. As well, particles with sharp edges can injure the mucous layer of the gastrointestinal tract. Furthermore, persistent organic pollutants adhere at plastic and thus, may cause adverse impacts on the animal. We show options for solutions and indicate selected organisations working on the development of solutions.     

Mapping dystrophin gene recombinants in Greek DMD/BMD families: low recombination frequencies in the STR region

A systematic study of 42 Greek DMD/BMD families using 14 polymorphic markers that span the dystrophin gene was performed in order to assess the position and frequency of recombinants in the Greek population and to test whether hot spots of recombination and deletions coincide when exclusively studying DMD/BMD families. We report a low percentage of recombination between markers STR44 and STR50; otherwise, the distribution of recombination events in other parts of the gene is largely in agreement with previously published data on Centre d'Etude du Polymorphisme Humaine families. We therefore propose that recombination frequencies and the correlation between recombination and deletion hot spots should be evaluated on DMD/BMD families exclusively.     

The Effect of Four Anaesthetic Protocols for Maintenance of Anaesthesia on Trans-Diaphragmatic Pressure in Dogs

The diaphragm is the main inspiratory muscle and the main indicator of diaphragmatic contractility is the trans-diaphragmatic pressure (P_di). The aim of this clinical study was to determine the effect of four different anaesthetic protocols on P_di in anaesthetized healthy dogs. Eighty client-owned dogs were recruited in this clinical study. All the animals received dexmedetomidine and morphine as premedication and propofol for induction. Anaesthesia was maintained with one of four protocols: isoflurane (I), isoflurane with CRI of propofol (IP), isoflurane with CRI of fentanyl (IF), and isoflurane with CRI of ketamine (IK). When the surgical plane of anaesthesia was achieved, two balloon catheters were inserted, one into the stomach and one into the mid-third of the oesophagus for P_di measurement. P_di value was the highest in groups I (14.9±4.7 mmHg) and IK (15.2±3.5 mmHg) and the lowest in groups IP (12.2±3.2 mmHg) and IF (12.0±5.9 mmHg). There was a statistically significant difference (p = 0.029) between groups IK and IF. PE’CO₂ was statistically significantly higher (p<0.0005) in group IF (7.7±0.8 kPa) than in group IK (6.5±0.7 kPa). Isoflurane alone or isoflurane with ketamine for the maintenance of anaesthesia seem to better preserve the respiratory function and the diaphragmatic contractility than isoflurane with either propofol or fentanyl in dogs. Therefore, the use of isoflurane or isoflurane with ketamine may be of benefit when animals with respiratory problems have to be anaesthetized.