Endoscopy and autopsy follow-up of biodegradable Oesophageal Anastomoses in dogs

The Biofragmentable Anastomosis Ring (BAR) is a mechanical device composed of absorbable material and creates an inverting, atraumatic compressive anastomosis with no foreign material at the anastomotic site after healing. The aim of the present experimental study was to assess the safety of oesophagoscopy in early days after oesophageal anastomoses performed with the BAR and to follow-up the healing of BAR anastomoses by in vivo endoscopy and autopsy examination. Thirty mongrel dogs divided into subgroups according to the timepoints of endoscopy and autopsy (4th, 7th, 14th, 28th day) were used. There was no significant difference in the healing of anastomoses performed under or above the tracheal bifurcation. Pleural adhesions helped to cover and seal small subclinical leaks. The mortality was 13.3% (4 dogs) and the overall leakage rate 14.3%. We looked for bleeding, haematoma, erosion, ulceration and granulation tissue in the anastomosis. Due to the high mechanical strength of these anastomoses, oesophagoscopy was a safe, easy and feasible method for follow-up BAR intrathoracic anastomoses, with no significant difference between the number of lesions found with endoscopy as compared to the autopsy data. The overall sensitivity of oesophagoscopy to discover mucosal lesions was 73.1%. Endoscopy had no complications, therefore it is a useful method of follow-up and may help predict the normal or compromised healing of oesophageal anastomoses

Continuous and discontinuous nectar secretion in some pear cultivars

Hourly nectar secretion was studied in five pear cultivars between 1997-1999. Some cultivars (e.g. ‘Csákvári téli') secreted nectar continuously during the whole day, offering both nectar and pollen for pollinating insects. Discontinuous secretion (e.g. cvs. ‘Viki', `Nyárig tartó 6/19') is less advantageous from the viewpoint of insect attraction. In some cases, however, discontinuity or continuity of nectar secretion varied even within a cultivar (e.g. 'Solymári cukor', ’Jó szürke’) in different years

Continuous and discontinuous nectar secretion in some pear cultivars

Hourly nectar secretion was studied in five pear cultivars between 1997-1999. Some cultivars (e.g. ‘Csákvári téli') secreted nectar continuously during the whole day, offering both nectar and pollen for pollinating insects. Discontinuous secretion (e.g. cvs. ‘Viki', `Nyárig tartó 6/19') is less advantageous from the viewpoint of insect attraction. In some cases, however, discontinuity or continuity of nectar secretion varied even within a cultivar (e.g. 'Solymári cukor', ’Jó szürke’) in different years

The effect of rootstock on the nectar production of apple cultivar `Idared'

Approaches based on the daily rhythm of apple flowers provide a new stage in nectar research, where the synchronous functioning of sexual organs is studied. In the flower biological studies the insect attraction of flowers was also studied. The two most important factors of insect attraction are the pollen- and nectar production of the flowers. From 1993 to 1998 we studied the food, that flower had to offer for the pollinating insects at different times of the day. Studies were carried out on 'Idared', one of the hybrids of 'Jonathan' apple cultivar. The fruit of 'Idared' is bigger than the fruit of `Jonathan'. It is bright red, transportable, has a bigger productivity and is not subject to Jonathan-spots. Concerning its inner characteristics, it is juicy, the flesh consistency is better than that of 'Jonathan', but its acid/sugar ratio is worse (Sansavini et al. 1981). &nbsp

The effect of rootstock on the nectar production of apple cultivar `Idared'

Approaches based on the daily rhythm of apple flowers provide a new stage in nectar research, where the synchronous functioning of sexual organs is studied. In the flower biological studies the insect attraction of flowers was also studied. The two most important factors of insect attraction are the pollen- and nectar production of the flowers. From 1993 to 1998 we studied the food, that flower had to offer for the pollinating insects at different times of the day. Studies were carried out on 'Idared', one of the hybrids of 'Jonathan' apple cultivar. The fruit of 'Idared' is bigger than the fruit of `Jonathan'. It is bright red, transportable, has a bigger productivity and is not subject to Jonathan-spots. Concerning its inner characteristics, it is juicy, the flesh consistency is better than that of 'Jonathan', but its acid/sugar ratio is worse (Sansavini et al. 1981). &nbsp

Floral biological studies on pear cultivars in relation to fire blight susceptibility

Floral biological characteristics that may influence cultivar susceptibility to fire blight were studied in 10 pear cultivars in two Hungarian orchards from 1999 to 2003. The receptaculo-ovarial, automorphic nectary is usually bigger in tolerant cultivars than in susceptible ones. Nectary stomata are meso- or xeromorphic. Susceptible cultivars tend to have more xeromorphic stomata, where guard cells are located 1-3 cell rows below the epidermis. The size of nectar chambers is usually smaller in susceptible cultivars. Floral nectar, consisting mainly of glucose and fructose, is more abundant and less concentrated if the cultivar is susceptible to fire blight. The amount of chlorogenic acid was higher in the flowers of tolerant cultivars than in susceptible ones

Floral biological studies on pear cultivars in relation to fire blight susceptibility

Floral biological characteristics that may influence cultivar susceptibility to fire blight were studied in 10 pear cultivars in two Hungarian orchards from 1999 to 2003. The receptaculo-ovarial, automorphic nectary is usually bigger in tolerant cultivars than in susceptible ones. Nectary stomata are meso- or xeromorphic. Susceptible cultivars tend to have more xeromorphic stomata, where guard cells are located 1-3 cell rows below the epidermis. The size of nectar chambers is usually smaller in susceptible cultivars. Floral nectar, consisting mainly of glucose and fructose, is more abundant and less concentrated if the cultivar is susceptible to fire blight. The amount of chlorogenic acid was higher in the flowers of tolerant cultivars than in susceptible ones

Morphological characterisation of the floral nectary in some apple-shaped and pear-shaped quince cultivars

The receptaculo-ovarial nectary of quince is located on the adaxial surface of the hypanthium. The glandular tissue is protruding out of the basal part of the receptacular tissue, but the apical part of the nectary is epimorphic. The glands can have various shapes if observed in the median longitudinal section of the flower and gland shapes are characteristic to the cultivars. The anisodiametrical cells of the nectarial epidermis are arranged in one or two rows. The surface of the nectary is covered by cuticle, the thickness of which depends on climatic conditions. Stomata of the nectary are mesoxeromorphic, the guard cells are sunken below the outer anticlinal wall of the epidermis cells. The investigated pear-shaped quince cultivars have more sunken stomata than the apple-shaped ones. Both the glandular tissue and the nectary parenchyma are the thickest on the basal part of the nectary, but taper on the apical part. The nectary parenchyma cells differ from the receptacular ones in shape and size. The phloem bundles, supplying the nectary, do not enter into direct contact with the secretory tissues.The morphological and histological differences that can be found between the nectary of cvs. ‘Konstantinápolyi’ and cvs. ‘Dunabogdányi’, as well as between the gland of the investigated apple-shaped cultivars and pear-shaped ones, can have taxonomic importance and could refer to the various degree of susceptibility of the cultivars to Erwinia amylovora

Carbohydrate utilization of Erwinia amylovora in vitro

Nectar is a multi-component aqueous solution that promotes bacterial multiplication. The concentration of nectar in plant flowers is not stable since it is under the influence of environmental conditions, especially free moisture and relative humidity. Experiments were conducted with "artificial nectar" and directed along two lines: (1) determination of the optimal concentrations of carbohydrates for the growth of E. amylovora development (2) consumption of different carbohydrates besides basic sugars. Solutions of "artificial nectar" were prepared in different compositions by changing the dominance of basic sugars (fructose — glucose —sucrose) in proportions of 2:1:1, 1:2:1, 1:1:2 and between concentrations of 10-0.6% (diluted with Basal minimum broth) in order to determine optimal conditions for the development of E. amylovora. At a basic sugar concentration of 10% bacterial multiplication started and continued until I log degree (from 106 to 107 cfu/ml). At concentrations of 5% and 2,5 % cells developed with nearly the same kinetics (from 106 to 8x107 cfu/ml and from 106 to 9x107 cfu/ml, respectively). Multiplication was more pronounced and nearly the same at concentrations of 1.2 % and 0.6 % (from106 to 2x108 cfu/ml). At a basic sugar concentration 30% total sugars bacterial multiplication did not occur, while at 20 % it was negligible, not measurable photometrically. At minimal concentrations of F, G, S (between 1-0.1 %) bacterial cells were still able to multiply, producing organic acids from sugars. Our study showed that E. amylovora requires only a small amount of sugars (0.1%) for multiplication (acid production) while high concentrations inhibit multiplication. There was a negative correlation between sugar content and cell density. The optimal range of sugar concentration was at about 1%. Effect of "less frequent carbohydrates" to E. amylovora multiplication was also determined using the API 50 CH strip. We could provide information on utilization of 39 carbohydrates by the bacterium at different categories as follows: Not utilized-, Slowly and weakly utilized-, Slowly and completely utilized-, Quickly and completely utilized carbohydrates. We suppose that carbohydrates that belong to the latter two groups could play an important role as nectar components in promoting E. amylovora multiplication in the blossoms of pome fruit trees