Identification of nine sequence types of the 16S rRNA genes of Campylobacter jejuni subsp. jejuni isolated from broilers

Background

Campylobacter is the most commonly reported bacterial cause of enteritis in humans in the EU Member States and other industrialized countries. One significant source of infection is broilers and consumption of undercooked broiler meat. Campylobacter jejuni is the Campylobacter sp. predominantly found in infected humans and colonized broilers. Sequence analysis of the 16S rRNA gene is very useful for identification of bacteria to genus and species level. The objectives in this study were to determine the degree of intraspecific variation in the 16S rRNA genes of C. jejuni and C. coli and to determine whether the 16S rRNA sequence types correlated with genotypes generated by PFGE analysis of SmaI restricted genomic DNA of the strains.

Methods

The 16S rRNA genes of 45 strains of C. jejuni and two C. coli strains isolated from broilers were sequenced and compared with 16S rRNA sequences retrieved from the Ribosomal Database Project or GenBank. The strains were also genotyped by PFGE after digestion with SmaI.

Results

Sequence analyses of the 16S rRNA genes revealed nine sequence types of the Campylobacter strains and the similarities between the different sequence types were in the range 99.6–99.9%. The number of nucleotide substitutions varied between one and six among the nine 16S rRNA sequence types. One of the nine 16S rRNA sequence profiles was common to 12 of the strains from our study and two of these were identified as Campylobacter coli by PCR/REA. The other 10 strains were identified as Campylobacter jejuni. Five of the nine sequence types were also found among the Campylobacter sequences deposited in GenBank. The three 16S rRNA genes in the analysed strains were identical within each individual strain for all 47 strains.

Conclusion

C. jejuni and C. coli seem to lack polymorphisms in their 16S rRNA gene, but phylogenetic analysis based on 16S rRNA sequences was not always sufficient for differentiation between C. jejuni and C. coli. The strains were grouped in two major clusters according to 16S rRNA, one cluster with only C. jejuni and the other with both C. jejuni and C. coli. Genotyping of the 47 strains by PFGE after digestion with SmaI resulted in 22 subtypes. A potential correlation was found between the SmaI profiles and the 16S rRNA sequences, as a certain SmaI type only appeared in one of the two major phylogenetic groups.     

Effect of restricted suckling on milk yield,milk composition and udder health in cows and behaviour and weight gain in calves,in dual-purpose cattle in the tropics

The study was conducted to evaluate the effects of restricted suckling (RS) in dual-purpose cows and calves compared to artificial rearing (AR). Twelve Holstein-Zebu cows with calves were assigned to each treatment. Cows were milked once daily in the morning with calves present to stimulate milk let-down. RS calves suckled 30 min after milking and 30 min in the afternoon, whereas AR calves were milk-fed from nipple bottles. The daily saleable milk yield was higher in RS than in AR cows (p < 0.01; 7.44 vs 6.50 kg/day), whereas RS cows had lower milk-fat content (p < 0.001). AR cows had higher California Mastitis Test scores (p < 0.001) and lower lactose content (p < 0.001) compared to RS cows, which indicates an improved udder health in RS cows. AR calves displayed more ‘cross-suck’ during suckling/milk feeding (p < 0.001) and during observations of general behaviour (p < 0.05), and more ‘lick and sniff interior’ during milking (p < 0.05) and suckling/milk feeding (p < 0.01), compared to RS calves. During observations of general behaviour the RS calves were more often observed to ‘walk’ (p < 0.01) and ‘lick self’ (p < 0.05) and less frequently to ‘eat concentrate’ (p < 0.05) than AR calves. Results support the hypothesis that RS increases milk yield, influences milk composition and improves udder health in cows, and decreases abnormal sucking in calves.     

The role of the environment in partial migration: food availability affects the adoption of a migratory tactic in brown trout Salmo trutta

Abstract –  Alternative reproductive tactics are commonly reported for salmonids (Pisces) and typically involve large migratory and small resident individuals. Variation in migratory tendency should reflect the different benefits and costs that the two different phenotypes face with regard to fitness. Therefore, the effect of food availability on the adoption of a migratory tactic in brown trout was investigated. Fifty trout were placed in each of 12 tanks and fed at three different levels. Growth-related variables were measured regularly, and at the end of the experiment, the proportion of migrants and residents was recorded. Low food availability led to increased numbers of migratory fish. The expected sex-bias was also present, with a lower percentage of resident females than resident males. As all fish originated from the same gene pool, the changing proportions of the migratory tactics can be classified as phenotypic plasticity. The study provides evidence that the different phenotypes reflect alternative tactics within a conditional strategy. Some differences in growth-related variables were present between the sexes, and a very pronounced difference in condition factor was found between resident and migratory males, but not in females. Thus, the results provide evidence that different selective forces may be acting on the sexes.     

Evolutionary analysis of plant jacalin-related lectins (JRLs) family and expression of rice JRLs in response to Magnaporthe oryzae

Jacalin-related lectins (JRLs) are widely distributed carbohydrate-binding proteins in the plant kingdom, which play key roles in development and pathogen defense. In this study, we profiled evolutionary trajectory of JRLs family in 30 plant species and identified domain diversification and recombination leading to different responsive patterns of JRLs in rice during defense against rice blast. All of 30 plant species analyzed in our study have two types of JRLs by containing either a single jacalin or repeated jacalin domains, while chimeric jacalins exist in more than half of the species, especially in the Poaceae family. Moreover, Poaceae species have evolved two types of unique chimeric JRLs by fusing the jacalin domain(s) with dirigent or NB_ARC domain, some of which positively regulate plant immunity. Seven Poaceae-specific JRLs are found in the rice genome. We further found expression of rice JRLs, including four Poaceae-specific JRLs, are induced by Magnaporthe oryzae infections at either early or late infection stages. Overall, the results present the evolutionary trajectory of JRLs in plant and highlight essential roles of Poaceae specific JRLs against pathogen attacks in rice.     

Zoospore chemotaxis of closely related legume‐root infecting Phytophthora species towards host isoflavones

Phytophthora niederhauserii, P. pisi, P. sojae and P. vignae are closely related species that are pathogenic to various legume plants. While P. sojae and P. vignae are reported to specifically infect soybean and cowpea, respectively, P. pisi is reported to attack pea and faba bean. Phytophthora niederhauserii is considered to have a broad host range. Zoospores of some Phytophthora species are chemotactically attracted to the isoflavones that are secreted by their host plants. The focus of the current study was to determine the chemotaxic behaviour of zoospores from closely related legume‐root infecting Phytophthora species and to investigate the correlation, if any, to host preference as determined by greenhouse pathogenicity tests. The results showed that P. sojae and P. vignae were attracted to the non‐soybean isoflavone prunetin as well as to the soybean isoflavones genistein and daidzein, which is in contrast with their host specificity on soybean and cowpea, respectively. On the other hand, P. pisi and P. niederhauserii were only attracted to prunetin, previously reported to be produced by pea, but not to the isoflavones associated with the non‐host soybean. The lack of responsiveness to genistein and daidzein in P. pisi may represent a recent adaptation to the host specialization towards pea. However, the affinity of P. niederhauserii to prunetin shows that this trait can also be present in taxa not specifically associated with legume hosts.     

Single nucleotide polymorphisms found in the red alga Furcellaria lumbricalis (Gigartinales): new markers for population and conservation genetic analyses

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Comparison of wood,fibre and vessel properties of drought-tolerant eucalypts in South Africa§

Three drought-tolerant eucalypt genotypes have been investigated for a broad spectrum of properties to provide a basis for comparison on their suitability for various end-uses. The genotypes included were a Eucalyptus grandis × E. camaldulensis hybrid, E. gomphocephala and E. cladocalyx, selected based on previous studies that indicated good potential to tolerate arid conditions, reasonably good volume growth and straightness of stems. In this study, information was added on differences between species and parts of stems in growth (volume and biomass) and properties of wood (density and stiffness), fibres (dimensions and microfibril angle) and vessels (size and numbers). We found high wood densities and stiffness values for E. cladocalyx and E. gomphcephala, making them suitable for construction wood. Logs from the mid-part of the stem had the best timber properties, as the butt logs showed the highest microfibril angle and lowest wood stiffness due to longitudinal juvenility. Such juvenility was also to some degree observed for wood density and fibre length. The information gained will be especially helpful for selecting species and processing options for small farm and community plantations for producing higher-value products that may be sold to generate much-needed income as well as for local uses, such as fuelwood and charcoal.     

Effects of granivorous rodents on direct seeding of oak and beech in relation to site preparation and sowing date

Planting bare-rooted seedlings is a rather expensive method to regenerate oak (Quercus robur) and beech (Fagus sylvatica). Direct seeding could reduce artificial regeneration costs substantially, but the method currently suffers from a number of problems, one of which is seed consumption by rodents. In the present study clear-cut areas in southern Sweden were prepared using one of four different mechanical site preparation methods – disc trenching, patch scarification, topsoil removal or mounding – then manually sown with acorns and beech nuts. Acorns were sown in May and July 2006, and both acorns and beech nuts were sown in May 2007. Three years following sowing, best seedling establishment from viable acorns, 60–70%, was achieved after sowing in mounds in May, and the subsequent survival reached 90–100%. After the first growing season for beech, both seedling establishment and subsequent survival was lower than for oak, which coincides with a higher number of lost beech nuts at the excavation to investigate the fate of seeds. Granivorous rodents (Apodemus flavicollis, A. sylvaticus, Mus musculus, and Myodes glareolus) were live-trapped more frequently in the vicinity of slash piles compared to other micro-site features, such as uprooted stumps, snags and stones. In 2006, no connection was found between number of rodents captured and proportion of lost seeds, while in 2007 the two were in good accordance. No clear relationship was found between number of captured rodents, vegetation cover class and mechanical site preparation method. More rodents were captured in 2007 than in 2006, and there was an increase in captures from spring until late summer/autumn for both years, which was mirrored in the seedling establishment result from the three different times of sowing. Based on experiences from the present study the recommendation for successful direct seeding of oak on clear-cuts is a combination of mounding site preparation, removal of slash and sowing in May rather than July. However, the results indicate that successful direct seeding of beech is more difficult to achieve.     

Comparison of haemodynamic changes during two surgical methods for neutering female dogs

The aim was to investigate if intraoperative registrations of blood pressure and heart rate could be used to estimate surgical trauma. In a prospective clinical trial, registrations in eight dogs neutered by laparoscopic ovariectomy (LOE) were compared with eight dogs subjected to open ovariohysterectomy (OHE). For comparisons phases were used: phase zero = steady state after induction of anaesthesia; phase one = opening of abdomen; phase two = severing of ovarian pedicles; and, phase three = abdominal closure. During LOE, mean systolic blood pressure increased by 7 mm Hg (p = 0.05) and 15 mm Hg (p = 0.01) from phase zero to phase one and two, respectively, and during OHE by 3 mm Hg (ns) and 29 mm Hg (p < 0.0001), respectively. The increase from phase one to phase two differed between groups (p = 0.03). Heart rate did not change. Frequent intraoperative measurements of blood pressure appear a promising method for evaluating surgical trauma.     

The influence of genotype on the effects of impact damage on the accumulation of glycoalkaloids in potato tubers

Summary The effects of impact damage on the accumulation of glycoalkaloids in tubers were studied in a wide range of potato genotypes. Damage, caused by drop tests, resulted in increased glycoalkaloid levels, which sometimes exceeded the toxic limit of 20 mg/100 g fresh weight; there were large differences in levels between genotypes. When the total damage index was high, the severe damage types—shatter cracks and splits—were responsible for the initiation of glycoalkaloid synthesis in stressed tuber tissue, whereas the less severe damage types—bruises and black spot—were not. Genotypes which had the highest shatter crack indices often had the greatest increases in glycoalkaloids. The high correlation between the initial glycoalkaloid level and the increased level after damage showed that selection for low glycoalkaloid potato clones is important.

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Zusammenfassung Der Einfluss von Stossverletzungen auf die Glykoalkaloide in Knollen wurde an 18 bis 21 Sorten und Zuchtklonen untersucht. Die Knollen liess man von 150 cm H?he (1981) bzw. 100 cm H?he (1982) herabfallen, um Stossverletzungen unterschiedlicher Typen (Schwarzfleckigkeit, Quetschungen, Schlagrisse, Brüche) und unterschiedlicher St?rke hervorzurufen. Der Gehalt an Glykoalkaloiden (α-Solanin und α-Chaconin) wurde an unbehandelten und besch?digten Knollen bestimmt. In unbehandeltem Material wurden wechselnde Glykoalkaloidgehalte aufgefunden (Tab. 1). Die Falltests ergaben grosse Sorten-differenzen hinsichtlich der Verletzungsemp-findlichkeit. Eine Fallh?he von 150 cm verursachte hohe Indizes für die Gesamtbesch?digung (Tab. 2). Unter den einzelnen Besch?digungs-typen waren Brüche und Schlagrisse am h?ufigsten. Der Glykoalkaloidgehalt erh?hte sich signifikant in den Knollen mit Stossverletzungen, und in einer Sorte wurde die toxische Schwelle von 20 mg/100 g Frischgewicht überschritten (Tab. 1). Die Glykoalkaloidbildung war signifikant korrelliert mit dem Schwellenwert in unbehandelten Knollen. Sorten und Klone mit den h?chsten Schlagriss-Indizes zeigten die gr?ssten Zunahmen. Eine zweimalige Fallbehandlung ergab h?here Verletzungsindizes und die Glykoalkaloidgehalte stiegen weiter an. Die Werte schwankten dabei zwischen 4 und 53 mg Glykoalkaloid/100 g Frischgewicht. Drei Sorten/Klone überschritten 20 mg/100 g und drei andere waren nahe an der toxischen Schwelle. Eine Fallh?he von 100 cm bewirkte auff?llig niedrigen Anteile an Stossverletzungen (Tab. 3). Schwere Verletzungenstypen, z.B. Schlagrisse und Brüche, waren hier nicht so h?ufig als weniger schwere, wie Quetschungen und Schwarzfleckigkeit. Der Glykoalkaloidgehalt war verglichen mit demjenigen in unbehandelten Knollen nur geringfügig h?her (Tab. 1). Das Glykoalkaloidniveau der besch?digten Knollen war gut korrelliert mit dem ursprünglichen Niveau, es stand aber weder zum Gesamtindex der Stossverletzungen noch zum Index irgendeines besonderen Besch?digungstyps in Beziehung. Der Grund dafür lag vermutlich in der geringen Anzahl von Verletzungen, insbesondere in der geringen H?ufigkeit von Schlagrissen. Eine zweimalige Fallbehandlung erh?hte signifikant den Gesamtverletzungsindex und die H?ufigkeit der Quetschungen. Dabei ergab sich ein geringer Zuwachs an Glykoalkaloiden mit einer sortenbedingten Differenz von 2–20 mg/100 g Frischgewicht. Der Glykoalkaloidgehalt war jedoch nicht korrelliert mit dem Index der gesamten Stossverletzungen oder, vielleicht mit Ausnahme der Quetschungen, mit dem Index irgendeines besonderen Besch?digungstyps. Die Untersuchung zeigte, dass schwere Stossverletzungen eine Erh?hung des Glykoalkaloidgehaltes in Kartoffelknollen verursachen. Die Pflanzenzüchtung ist ein m?glicher Weg, um die Resistenz gegenüber mechanischen Besch?digungen zu erh?hen, wenngleich stets eine sorgf?ltige Behandlung notwendig ist, um die Besch?digungsh?ufigkeit in der Handelsware zu reduzieren. Die hohe Korrellation zwischen dem ursprünglichen Glykoalkaloidniveau und dem erh?hten Niveau nach der Besch?digungsinduktion zeigt, dass es wichtig ist, Kartoffelklone mit geringem Glykoalkaloidgehalt zu selektieren.

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Résumé L'influence des endommagements par impacts sur les glycoalcalo?des dans les tubercules a été étudiée sur 18–21 variétés et clones de sélection. Les différents types d'endommagements (noircissement interne, meurtrissures, cavernes et fissures) ainsi que leur gravité sont analysés après une chute des tubercules d'une hauteur de 150 et 100 cm, respectivement en 1981 et 1982. La teneur en glycoalcalo?des (α-solanine et α-chaconine) est déterminée dans les tubercules n'ayant subi aucun traitement et dans les tubercules endommagés. Une grande variété de teneurs en glycoalcalo?des est observée dans les tubercules non endommagés (tabl. 1). Les tests d'impacts ont montré des différences variétales importantes, quant à la sensibilité à l'endommagement. La hauteur de chute de 150 cm a causé des indices d'endommagements élevés (tabl. 2). Les fissures et les cavernes sont les types d'endommagements les plus fréquents. La teneur en glycoalcalo?des augmente de fa?on significative dans les tubercules endommagés et pour une variété, le seuil de toxicité de 20 mg/100 g de poids frais est dépassé (tabl. 1). La réponse dans la formation de glycoalcalo?des est correlée de fa?on significative à la teneur initiale, dans les tubercules non endommagés. Les variétés et clones qui présentaient le plus grand nombre de cavernes ont eu les augmentations les plus fortes. Les traitements comprenant deux chutes ont donné les indices d'endommagements les plus élevés et des teneurs en glycoalcalo?des encore plus importantes. Celles-ci variaient entre 4 et 53 mg/100 g de poids frais. Trois variétés/clones ont dépassé les 20 mg pour 100 g et trois autres étaient très proches de ce seuil de toxicité. La hauteur de chute de 100 cm a conduit à des niveaux d'endommagements beaucoup plus faibles (tabl. 3). Les types d'endommagements graves, c'est-à-dire les cavernes et les fissures, furent moins fréquents que les autres types d'endommagements moins graves: les meurtrissures et le noircissement interne. Il n'y eut qu'une légère augmentation des teneurs en glycoalcalo?des, comparée à celles des tubercules non endommagés (tabl. 1). Le niveau de glycoalcalo?des dans les tubercules endommagés est fortement correlé au niveau initial, mais n'est pas lié à l'indice total d'endommagements ni à l'indice d'un quelconque type d'endommagement. Ceci est probablement d? au faible niveau d'endommagement et notamment à la faible quantité de cavernes. Les traitements comprenant deux chutes ont donné un indice total d'endommagements plus élevé avec davantage de meurtrissures. La teneur en glycoalcalo?des a légèrement augementé, avec des différences variétales de 2–20 mg/100 g de poids frais. Toutefois, les glycoalcalo?des ne furent pas correlés à l'indice total ou à l'indice d'un des types d'endommagements, excepté peut être les meurtrissures. Cette recherche montre que les endommagements graves par impacts provoquent l'augmentation des teneurs en glycoalcalo?des dans les tubercules de pomme de terre. La sélection des variétés est un moyen pour augmenter la résistance des tubercules à l'endommagement, bien que des précautions dans les manutentions sont nécessaires pour réduire les fréquences d'impacts des pommes de terre de commercialisation. La forte corrélation entre le niveau initial de glycoalcalo?des et son augmentation après endommagement montre que la sélection des clones à faible teneur en glycoalcalo?des est importante.