Variability of some plant species from different origins and their suitability for virus work

Plants of four species obtained from various sources were raised and compared for their suitability as test plants for a number of viruses. The species comprisedChenopodium amaranticolor (local lesion host of red clover mottle virus),Nicotiana glutinosa (local lesion host of tobacco mosaic virus (TMV)),N. rustica (systemic host of TMV, cucumber mosaic virus and tomato spotted wilt virus) andN. tabacum ‘White Burley’ (systemic host of TMV). Some sources proved to be more attractive as test plants or experimental hosts because of, e.g., production of more local lesions per unit of leaf area (C. amaranticolor andN. glutinosa), distinctness of lesions (C. amaranticolor), development of more pronounced systemic symptoms (N. rustica andN. tabacum ‘White Burley’), better growth characteristics (particularlyC. amaranticolor andN. rustica), smoother leaves being easier to rub (N. glutinosa) or more and bigger leaf formation (particularlyN. rustica). The implications for the interpretation of host range studies and the quest for propagation and assays hosts are discussed.     

Temperature signals contribute to the timing of photoperiodic growth cessation and bud set in poplar

Bud set, the cornerstone delimiting the seasonal growth period in trees, is the dynamic net result of the often photoperiod-controlled growth cessation and the subsequent bud formation. Here, we show that in hybrid poplar, the critical day length for growth cessation and the duration of bud formation each vary with local climatic conditions in identical genotypes. The detailed dissection of bud set suggests temperature as one additional environmental factor that modifies the sensitivity to day-length signals at growth cessation and influences the duration of bud formation in poplar. The ability of perennial plants to integrate additional environmental signals with photoperiod signaling may add to short-term acclimatization to the predicted longer growing seasons in future climates.     

Purification and serological analysis of tomato spotted wilt virus

A modified procedure for the purification of TSWV is described which consists of differential centrifugation, treatment with antiserum against sap from healthyN. rustica and density-gradient centrifugation in sucrose gradients. Centrifugation in the zonal-rotor proved efficient for processing large amounts of infected leaves.Antisera to purified TSWV were produced in rabbits. These sera reacted with healthyN. rustica sap. This reaction could be abolished by absorption with either healthyN. rustica sap or polysaccharides purified fromN. rustica. Unabsorbed sera reacted with the major TSWV structural proteins following their electrophoretic separation in polyacrylamide-gels. The positions of the precipitin lines corresponded with those of the structural proteins visualized by staining. The intensity of these lines was greatly diminished after absorption of the antisera with either healthyN. rustica sap or polysaccharides. It was concluded that the reaction of TSWV antiserum with the structural proteins is partly due to host-derived polysaccharides covalently bound to the virus proteins.Samenvatting Het bronsvlekkenvirus van de tomaat (TSWV) werd gezuiverd met een procedure die bestond uit een cyclus van differentiële centrifugering, behandeling van de virus-suspensie met antiserum tegen bestanddelen van gezonde planten (N. rustica) en dichtheidsgradiëntcentrifugering (Fig. 1 en Fig. 3). De zone rotor kon worden gebruikt wanneer grote hoeveelheden bladmateriaal werden gebruikt (Fig. 2).Twee antisera, die elk een verschillende activiteit tegen TSWV (Tabel 1, Fig. 4) hadden, werden bereid. Deze sera reageerden ook met sap en polysacchariden uitN. rustica (Fig. 6). Door verzadiging met polysacchariden werd de reactie tegen TSWV aanmerkelijk verzwakt. Analyse van de eiwitbandjes die na polyacrylamidegel-elektroforese waren gevormd, toonde aan dat de activiteit van de sera tegen de eiwitcomponenten van TSWV was gericht (Fig. 5) en dat deze activiteit na verzadiging met polysacchariden zwakker was. Uit deze reacties kan geconcludeerd worden dat polysacchariden van de waardplant aan de structurele eiwitten van TSWV zijn gebonden. Niet geabsorbeerd antiserum geeft met TSWV drie precipitatielijnen (Fig. 4), maar na absorptie met compleet virus trad nog slechts één precipitatielijntje op (Fig. 7). Mogelijk wordt dit lijntje gevormd door het nucleocapside-eiwit dat door de dissociatie van het virus vrij komt. Sera die tegen normale bestanddelen vanN. rustica zijn bereid, vormen geen zichtbare reactie met compleet virus; wel wordt er een lijntje gevormd indien het virus met guanidine-HCl wordt gedissociëerd (Fig. 8). Deze waarneming kan verklaren dat deze antisera kunnen worden gebruikt bij de zuivering van TSWV ondanks het feit dat dit virus polysacchariden uit de waardplant draagt.     

Physiological response of temperature shocks in turbot and sole

In the present study, selected temperature drops were examined to investigate the effects of live chilling on stress and welfare in turbot and sole. This study demonstrated that rapid temperature drops from 11°C–12°C and 18°C–18.7°C to 4°C–0°C in turbot resulted in higher blood sodium and potassium at 0°C (164 mmol l^?1, 4.4 mmol ^?1) compared to 4°C (153 mmol l^?1, 3.1 mmol ^?1), indicating osmoregulatory disturbance. A rapid temperature drop from 18°C to 0°C in Senegal sole also resulted in higher blood sodium and potassium at 0°C (164 mmol l^?1, 4.8 mmol ^?1) compared to the control group at 18°C (157 mmol l^?1, 3.2 mmol ^?1). Based on present findings, we conclude that immersion in ice water will have a negative effect on the animal osmoregulatory capacity, and we recommend that turbot and sole are stunned before slaughter.     

清洗和消毒对猪病控制的重要性

很多养猪生产者都熟悉猪舍的现代清洗和消毒规程。但是,这些规程常常没有被正确地应用。由比利时佛兰德动物保健中心(Animal Health Care Flanders,DGZ)完成的研究发现,已经在养禽业中使用了很长一段时间的微生物监测法也可以在猪舍中使用,以检查猪舍清洗和消毒措施的效率。     

The genome of black cottonwood, Populus trichocarpa (Torr. & Gray)

We report the draft genome of the black cottonwood tree, Populus trichocarpa. Integration of shotgun sequence assembly with genetic mapping enabled chromosome-scale reconstruction of the genome. More than 45,000 putative protein-coding genes were identified. Analysis of the assembled genome revealed a whole-genome duplication event; about 8000 pairs of duplicated genes from that event survived in the Populus genome. A second, older duplication event is indistinguishably coincident with the divergence of the Populus and Arabidopsis lineages. Nucleotide substitution, tandem gene duplication, and gross chromosomal rearrangement appear to proceed substantially more slowly in Populus than in Arabidopsis. Populus has more protein-coding genes than Arabidopsis, ranging on average from 1.4 to 1.6 putative Populus homologs for each Arabidopsis gene. However, the relative frequency of protein domains in the two genomes is similar. Overrepresented exceptions in Populus include genes associated with lignocellulosic wall biosynthesis, meristem development, disease resistance, and metabolite transport.     

Isolation and Culture of Luminal Oviductal and Glandular Uterine Epithelia from the Pig (Sus scrofa)

Contents Pig luminal oviductal and glandular uterine epithelia were isolated and cultured to monolayers. Within 4–5 days after isolation the monolayers from glandular uterine epithelium reached confluency, while cultures of luminal oviductal epithelium needed 6–7 days to reach this stage. The epithelial character of the cultured cells was confirmed by scanning electronmicroscopy (SEM) and by demonstration of intermediate filaments using immunohitochemistry. SEM analysis revealed that the monolayers from luminal oviductal origin consisted of microvilli rich epithelial cells only. In SEM preparations from glandular luterine epithelium we observed microvilli bearing as well as ciliated epithelial cells. All isolates from glandular uterine epithelium contained connective tissue derived fibroblasts. In cryosections of fresh oviductal and endometrial tissues, epithelial cells did react specifically with anti-keratin while anti-vimentin was not bound. Cultured epithelial cells, however, reacted with both anti-vimentin and anti-keratin indicating that cells from oviductal or urterine origin might dedifferentiate with respect to intermediate filament expression when brought into culture. Inhalt: Isolierung und Kultur von Epithelzellen aus dem Eileiterlumen und von glandulären uterinen Epithelzellen beim Schwein (Sus scrofa) Porcine Epithelzellen aus dem Eileiterlumen und glanduläre uterine Epithelzellen wurden isoliert und als Monolayer kultiviert. Innerhalb von 4–5 Tagen nach der Isolierung waren die uterinen Epithelzellen zusammengewachsen. Epithelzellen des Eileiters benötigten 6–7 Tage um dieses Stadium zu erreichen. Der epitheliale Charakter der Zellen wurde durch elektronenmikroskopische Untersuchungen (SEM) und durch den immunhistologischen Nachweis intermediärer Filamente bestätigt. DieelektronenmikroskopischeUntersuchung zeigte, daβdie Monolayer aus den Eileiterzellen nur aus Mikrovilli-reichen Epithelzellen bestanden. Dagegen wiesen die glandulären Uterinzellen sowohl Zellen mit Mikrovilli als auch mit Zilien besetzte Epithelzellen bei der elektronenmikroskopichen Untersuchung auf. Alle isolierten Epithelzellen uterinen Ursprungs enthielten Fibroblasten aus dem verbindenden Gewebe. In Cryoschnitten frischer Eileiter- und Endometriumsgewebe reagierten die Epithelzellen spezifisch mit Anti-Keratin, wohingegen Anti-Vimentin nicht gebunden wurde. Epithelzellen aus der Kultur reagierten jedoch mit beiden Substanzen. Dies kann als Hinweis gewertet werden, daβ die Zellen in der Kulturphase in Abhängigkeit der Intermediärfilamente entdifferenziert werden.