The structure of the sternal bursa of turkeys.

The sternal bursa developed as a microscopically recognizable synovial sac in turkeys at about 4 1/2 to 6 weeks of age. In birds 12 weeks old it was difficult to delineate the bursa grossly although microscopically it was a definite structure. After 12 weeks, the walls of the bursa were thick enough that the limits of the sac could be determined grossly. The synovial membrane was in the subcutis, and microscopically was a vascular band of loose to dense connective tissue of variable thickness. Laterally the membrane was folded so that in cross section it appeared as a tonguelike projection of variable length into the cavity. The lining cells centrally were flat fibroblasts while laterally they were cuboidal, particularly over the lateral folds. In older turkeys the cuboidal lining cells were sometimes stratified.     

Population Structure of Phytophthora infestans in the Toluca Valley Region of Central Mexico

ABSTRACT We tested the hypothesis that the population of Phytophthora infestans in the Toluca valley region is genetically differentiated according to habitat. Isolates were sampled in three habitats from (i) wild Solanum spp. (WILD), (ii) land-race varieties in low-input production systems (RURAL), and (iii) modern cultivars in high-input agriculture (VALLEY). Isolates were sampled in 1988-89 (n= 179) and in 1997-98 (n= 389). In both sampling periods, the greatest genetic diversity was observed in RURAL and VALLEY habitats. Based on the Glucose-6-phosphate isomerase and Peptidase allozymes, the subpopulations from the three habitats were significantly differentiated in both sampling periods. In contrast to allozyme data for 1997-98, no differences were found among the three subpopulations for sensitivity to metalaxyl. Two groups of isolates identical for allozyme and mating type were further investigated by restriction fragment length polymorphism fingerprinting; 65% of one group and 85% of another group were demonstrated to be unique. The genetic diversity data and the chronology of disease occurrence during the season are consistent with the hypothesis that populations of P. infestans on wild Solanum populations are derived from populations on cultivated potatoes in the central highlands of Mexico near Toluca.     

Coxiella burnetii infection is associated with placentitis in cases of bovine abortion.

A positive score on a modified acid-fast (MAF)-stained smear test of fresh placenta was used to identify a group of bovine abortion submissions believed to be infected with Coxiella burnetii. Immunohistochemical (IHC) testing for Coxiella and Chlamydia antigens was performed on 14 MAF smear-positive cases as well as 29 MAF smear-negative cases received during the study period. Nine MAF smear-positive cases as well as 1 MAF smear-negative case were Coxiella-positive via the IHC test. No placentas were positive for Chlamydia antigen. Various histopathologic features were categorized for all placentas and the presence or absence of selected risk categories was also graded for each case. The results between Coxiella IHC-positive cases and Coxiella IHC-negative/MAF-negative cases were compared using Fisher's exact test (P value at 95% confidence). Significant associations were found between Coxiella IHC-positive cases and the presence of placental inflammation (P = 0.0027), placental necrosis (P = 0.012), fetal pneumonia (P = 0.0152), and the visibility of Coxiella-like organisms within trophoblasts on hematoxylin and eosin-stained sections (P < 0.0001). Histopathologic features of Coxiella IHC-positive placentas included infiltration of the chorionic stroma by mononuclear cells, necrosis of chorionic trophoblasts, and focal exudation of fibrin and neutrophils. The results indicate that MAF smears are a good screening tool for the presence of Coxiella in placentas from bovine abortion cases and that the detection of this pathogen in aborted placentas via traditional staining or IHC methods is usually associated with placentitis.     

The mRNA Expression Profiles of Five Heat Shock Protein Genes from Frankliniella occidentalis at Different Stages and Their Responses to Temperatures and Insecticides

The westem flower thrips, Frankliniella occidental＆ （Pergande） is a highly invasive pest that is able to exploit many crops across a wide range of environmental conditions. Five full-length cDNAs of heat shock protein （HSP） genes （Fo-HSP90, Fo-HSP70, Fo-HSP60, Fo-HSP40 and Fo-HSP28.9） were cloned from F. occidentalis, and their expression profiles were investigated under conditions of thermal stress and insecticide exposure, and at different stages during development, using real-time quantitative PCR. All five gene sequences showed high similarity to homologs in other species, indicating the conserved fimction of this gene family. HSP60 represents an informative phylogenetic marker at the ordinal taxonomic level within Insecta, but HSP90, which has two homologous copies in Hymenoptera, was not informative. The expression of Fo-HSPs under thermal stress suggests that Fo-HSP90, Fo-HSP70, and Fo-HSP28.9 are inducible by both cold and heat stress, Fo-HSP40 is only heat-inducible, and Fo-HSP60 is thermally insensitive. There were two patterns of cold induction of Fo-HSPs： one is from 0 to 4℃ and the other is around -8℃. All five Fo-HSPs genes were induced by exposure to sublethal concentrations of the insecticide avermectin. The expression of the five Fo-HSPs during different developmental stages suggests that they all play a role in development of F. occidentalis.     

Behavioral effects in monkeys of racemates of two biologically active marijuana constituents

Both dl-Delta(8)- and dl-Delta(9)-tetrahydrocannabinol produced marked alterations of behavior in rhesus and squirrel monkeys. Squirrel monkeys appeared to have visual hallucinations. Continuous avoidance behavior of squirrel monkeys was stimulated by both drugs, but high doses of dl-Delta(9)-tetrahydrocannabinol also caused depression after the stimulant phase. Complex behavior involving memory and visual discrimination in rhesus monkeys was markedly disrupted by both drugs.     

Large-scale changes in the abundance of common higher plant species across Britain between 1978, 1990 and 1998 as a consequence of human activity: Tests of hypothesised changes in trait representation

Presence of higher plant species was recorded in 1455 permanently marked quadrats located across Britain in 1978, 1990 and 1998 in a stratified, random sample of 259 1 km squares. Significant increases and decreases in frequency of each species were summarised as changes in the representation of simple traits, each of which had an established relationship with varying levels of fertility or disturbance. By testing the null hypothesis that the trait values represented among increasing or decreasing species were a random draw from the 1978 species pool, we determined the consistency of botanical change with changes in land-use in different vegetation types and landscape locations across Britain.Overall, 63% of significant changes in species occupancy were decreases and 37% increases. Trait changes were largely consistent with the impact of increased nutrient availability across vegetation types associated with inherently low fertility, such as infertile grassland, heath, bog and moorland. Linear habitats in lowland Britain saw trait changes consistent with secondary succession. Although trait changes were highly consistent with eutrophication in upland vegetation, the identity of the changing species left open the possibility that increased N deposition, sheep grazing intensity and local improvement could all have played a part.Recent changes in common plant species across Britain suggest that objectives for large-scale restoration and maintenance of plant communities must address four problems: (a) the increasing scarcity of stress-tolerant species in lowland species pools, (b) exploitation and maintenance of species populations on habitat fragments and linear features in the lowlands, (c) the spread and persistence of generalist species in upland Britain, (d) systemic nutrient enrichment in both lowland and upland environments.     

Increased crop yields following application of Bacillus penetrans to field plots infested with Meloidogyne incognita

We found Bacillus penetrans to be pathogenic to Meloidogyne incognita under field conditions. B. penetrans was added to the soil of field plots into which tobacco, soybeans or winter vetch were planted in sequence during 1981 and 1982. Tobacco and winter vetch (1981 and 1982) and soybeans in 1982 showed trends of increasing yields with decreasing pathogenicity of M. incognita. There was insufficient evidence to enable one to declare a similar trend for soybeans in 1981. B. penetrans reduced yield losses caused by M. incognita 23% for tobacco 1981, 38% for winter vetch 1981, 24% for tobacco 1982, 35% for soybeans 1982 and 55% for winter vetch 1982.