Evidence for papillomaviruses in ocular lesions in cattle

Negatively stained preparations of various ocular lesions, generally considered to be precursors to bovine ocular squamous cell carcinoma, were subjected to electron microscopic examination for viruses. Lesions examined included five conjunctival plaques, an acanthotic lesion from an eyelid, 15 conjunctival papillomas, two papillomas of the eyelid and two keratinised elongated proliferative lesions of the eyelid (cutaneous horns). Eight lesions contained particles that resembled papillomaviruses. These consisted of a conjunctival plaque, five conjunctival papillomas, a papilloma of the eyelid and one of the samples of cutaneous horn. The particles were present in small numbers and were found only after prolonged search. The finding of these particles suggests that papillomavirus may be involved in the aetiology of bovine ocular squamous cell carcinoma.     

Attaching and effacing Escherichia coli infection as a cause of diarrhea in young calves

A form of enteric Escherichia coli infection was identified in 60 calves from 59 farming operations. The E coli responsible for these infections principally colonized the colon, inducing a distinctive lesion described as attaching and effacing. Hemorrhagic enterocolitis or blood in the feces was observed on 40% of the farms. Of affected calves, 86.6% were dairy calves (average age, 11.8 days). Forty-four calves were infected concurrently with other enteropathogens (cryptosporidia, rotavirus, coronavirus, enterotoxigenic E coli, bovine viral diarrhea virus, coccidia). Verotoxin-producing E coli was recovered from 31 calves; 8 were serotype O111:NM isolates, 3 were serotype O5:NM, and 1 was serotype O26:NM.     

RADIOGRAPHIC ASPECTS OF GASTRIC ULCERS IN DOGS

This paper is a retrospective analysis of the radiographic appearance of one benign and four malignant gastric ulcers in dogs. The benign gastric was diagnosed radiographically following gastric surgery and was healed at necropsy 28 months after diagnosis. Malignant gastric ulcers were confirmed at surgery and/or necropsy. None of the five ulcers penetrated the normally expected gastric contour. Mucosal fold pattern was either partially or completely effaced with all five ulcers. Undermining appeared to be present asymmetrically in the benign and one malignant ulcer, and symmetrically in one malignant ulcer. Tissue surrounding the ulcers joined the normal gastric wall very abruptly in three malignant ulcers. This transition was more gradual in the benign ulcer and was not identified in one malignant ulcer. None of these ulcers completely fit the criteria used in people to diagnose benign gastric ulcer. Prospective evaluation of more cases with a more thorough radiographic technique is needed     

Use of immunofluorescence, Gram's staining, histologic examination, and seroagglutination in the diagnosis of porcine colibacillosis

An indirect fluorescent antibody (IFA) test of ileal impression smears for K88, K99, and 987P pilus antigens was compared with histologic examination and seroagglutination of Escherichia coli isolates for efficacy in determining colibacillosis in pigs. Histologic examination appeared to be more effective than the IFA test in revealing colonization of the ileum by bacteria. However, histologic examination revealed little about the nature of the colonizing bacteria. Correlation between bacterial adherence, as observed in histologic sections of ileum, and the presence of bacteria with adherence pili, as determined by IFA testing, was 91%. Results of seroagglutination for pilus antigens correlated with results of histologic examination in only 84% of the cases. Pilus antigens were not identified by IFA testing or seroagglutination in 5% of the cases in which adherent bacteria were observed in histologic sections of the small intestine. Because little preparation time was required for the IFA test, results were available within 2 hours of necropsy. In contrast to histologic examination, the IFA test made possible identification of the colonizing organism as E coli and revealed the type of pilus antigen present. Adherence pili were identified more frequently by IFA testing than by seroagglutination. Examination of Gram's-stained ileal impression smears was useful in screening for colibacillosis in pigs. Bacterial adherence was found in positive correlation with the number of gram-negative bacilli observed. Bacterial adherence rarely was observed in histologic sections of ileum when smears contained less than or equal to 10 gram-negative bacilli/1,000 X microscopic field. Each diagnostic test compared offered advantages and disadvantages over the other tests. Seemingly, concurrent use of several of these tests, rather than one, should be used in the diagnosis of porcine colibacillosis.     

The effect of some herbicides on vesicular-arbuscular endophyte abundance in the soil and on infection of host roots

The effect of the herbicides di-allate, diquat, diuron, paraquat, tri-allate and trifluralin, at a range of application rates from 0.5 to 32 times that recommended by the manufacturers, on vesicular-arbuscular (V-A) endophyte spore abundance in the soil and on infection of wheat roots was investigated in field and glasshouse experiments. Paraquat and diquat had no measurable effect on V-A endophyte spore abundance. There was a slight trend to lower V-A endophyte spore numbers at high rates of application of di-allate and tri-allate but no trend for the other chemicals. Infection intensity (% root length infected) declined at high rates of di-allate and led to lower mycorrhizal root weights. The phosphorus content of the shoots was also reduced by di-allate. High doses of di-allate, diuron, tri-allate and trifluralin reduced most parameters of plant growth more than mycorrhizal parameters. It is therefore concluded that at normal application rates these chemicals are unlikely to affect adversely endomycorrhiza formation or function.     

Specific Behaviour of French Aphanomyces Euteiches Drechs. Populations For Virulence and Aggressiveness on Pea, Related to Isolates from Europe, America and New Zealand

The pathogenic variability of Aphanomyces euteiches on pea was investigated using a collection of 88 pea-infecting isolates from France and 21 isolates from Denmark, Sweden, Norway, USA, Canada and New Zealand. Aggressiveness and virulence were assessed by scoring the root symptoms on a differential set of six pea genotypes. Eleven virulence types were characterised. The virulence type I, previously described as virulent on the whole set, was predominant and included the most aggressive isolates of all geographical origins. The other types were much less prevalent, existing as one to five isolates. Three virulence types (III, IV and V) contained no French isolates. The type III, avirulent on MN313, was composed of American isolates only, and resembled the major group recently described in the USA. A wide range of aggressiveness was found within the virulence type I, and the French isolates appeared globally more aggressive than the foreign isolates. These findings indicate that isolates from the virulence type I should be used as references in breeding programs, and that pea lines PI180693 and 552 may be the most interesting resistance sources to date, despite their only partial resistance.     

Genetic variation in salt tolerance at the seedling stage in an interspecific backcross inbred line population of cultivated tetraploid cotton

Soil salinity reduces cotton growth, yield, and fiber quality and has become a serious problem in the arid southwestern region of the Unites States. Development and planting of salt-tolerant cultivars could ameliorate the deleterious effects. The objective of this study was to assess the genetic variation of salt tolerance and identify salt tolerant genotypes in a backcross inbred line (BIL) population of 142 lines from a cross of Upland (Gossypium hirsutum) × Pima cotton (G. barbadense) at the seedling growth stage. As compared with the non-saline (control) conditions, seedlings under the salinity stress (200 mM NaCl) showed a significant reduction in all the plant growth characteristics measured, as expected. Even though the two parents did not differ in salt response as measured by percent reduction, significant genotype variations in the BIL population were detected for all traits except for leaf number. Based on percent reduction of the traits measured, several BILs were more salt tolerant than both parents. The results indicate that transgressive segregation occurred during the process of backcrossing and selfing even though both parents were not salt tolerant during seedling growth. Coefficients of correlation between all the traits were significantly positive, indicating an association between the traits measured. The estimates of broad-sense heritability were 0.69, 0.46, 0.47, 0.43, and 0.49 for plant height, fresh weight of shoot and root, and dry weight of shoot and root, respectively, indicating that salt tolerance during cotton seedling growth is moderately heritable and environmental variation plays an equally important role. The overall results demonstrate that backcrossing followed by repeated self-pollination is a successful strategy to enhance salt tolerance at the seedling stage by transferring genetic factors from Pima to Upland cotton.     

Differential response of cocoa (Theobroma cacao) families to field establishment stress

High seedling mortality during the establishment phase of cocoa has become a critical constraint to sustainable cocoa farming. The objective of this study was to develop varieties with higher seedling survival compared with cultivars currently recommended for planting in denuded regions. Thirty‐seven families composed into two sets of 18 (families from recommended clones) and 19 (families from recently introduced clones) were evaluated for field survival under full sunlight and dry weather conditions. Families differed significantly for vigour (increase in trunk cross‐sectional area, TCSA) and percentage of survived seedlings by the end of the dry weather conditions. Survival and vigour were significantly correlated in only one set of families. The contribution of general combining ability (GCA) to seedling survival was low to moderate. An Amelonado clone and clones from the Iquitos genetic group had negative GCA estimates for both increase in TCSA and survival. Clones of Scavina origin had the most positive contribution to survival. The key outcome of the study was that cocoa families with higher establishment success can be obtained from the currently available germplasm.     

Development of in vitro produced porcine embryos according to serum types as macromolecule

This study was conducted to establish an in vitro maturation (IVM) system by selection of efficient porcine serum during porcine in vitro production. To investigate the efficient porcine serum (PS), different types of PS [newborn pig serum, prepubertal gilt serum (PGS), estrus sow serum, and pregnancy sow serum] were used to supplement IVM media with or without gonadotrophin (GTH) and development rates of parthenogenetic activation (PA) and in vitro fertilization (IVF) embryos were then compared. The maturation rates of the PGS group was significantly higher when GTH was not added. Additionally, during development of PA embryos without GTH, the PGS group showed significantly higher cleavage and blastocyst formation rates. Moreover, the cleavage rates of IVF embryos were significantly higher in the PGS group, with no significant differences in the blastocyst formation. However, when GTH was supplemented into the IVM media, there were no significant differences among the four groups in the cleavage rates, development rates of the blastocyst, and cell number of the blastocyst after PA and IVF. In conclusion, PGS is an efficient macromolecule in porcine IVM, and GTH supplementation of the IVM media is beneficial when PS is used as macromolecule, regardless of its origin.