Behavior disruption in Cebus monkeys as a function of injected substances

Intraperitoneal injections of blood substances from schizophrenic or stressed normal human donors into primates trained to perform a precision timing task resulted in significant prolongation of time taken to complete the task as compared with injections of blood substances from normal donors.     

Prospects for functional analysis of effectors from cereal rust fungi

With the advancement of several Puccinia genome sequencing projects, along with gene expression data and methods for predicting secreted proteins, it is now possible to predict many effector proteins from the cereal rusts. Biological assays that can be conducted in a relatively high throughput fashion are necessary to assign specific functions, such as avirulence. Biolistic delivery of potential effectors is limited by the need to examine individual cells and delivery by Agrobacterium generally also affects small numbers of cells in grasses. An approach that has had some success in dicots is the use of bacterial systems to deliver proteins by their type III secretion systems (TTSS). Several bacterial systems were thus tested for their suitability in delivering effectors to wheat. Pseudomonas syringae DC3000 caused hypersensitive reactions (HR) when infiltrated into all tested wheat lines but only some barley lines. A variant strain with multiple effectors deleted showed a reduced HR on wheat lines. Pseudomonas fluorescens with an engineered TTSS system showed no HR in wheat lines but was able to deliver bacterial effectors AvrRpm1 and AvrRpt2 and the fungal toxin ToxA. Delivery of the effectors by P. fluorescens could be detected by HR or by staining for presence of hydrogen peroxide or callose deposits. The bacterial systems thus showed good potential for their ability to deliver foreign proteins into wheat cells.     

Tree Recruitment from On-site Versus Off-site Propagule Sources During Tropical Forest Succession

The management of successional forests has become an increasingly important tool for tropical forest restoration on disturbed lands. Successful management depends on understanding factors governing tree recruitment during succession. Recruits can be on-site propagules surviving disturbance (e.g. saplings) or seeds arriving after disturbance. Among disturbed sites, the importance of seed arrival from off-site should increase as availability of on-site propagules declines. This study examines how seed arrival from off-site seemed to influence natural forest regrowth on logged plantations in Uganda. Specifically, the effect of seed arrival from mammals (determined directly) and birds (determined inferentially) was estimated in two plantations with high and three plantations with low quantities of saplings surviving logging. In both plantation types, first-year recruitment seemed to originate from on-site (seed bank and sprouts from damaged trees) and off-site sources (seed-dispersing birds). Recruitment declined 2–3 years after logging in all plantations despite high densities of seed-dispersing birds. Recruitment was generally greater in plantations with low initial quantities of on-site propagules, and by 4–6 years forest structure was similar between plantation types. Recruitment was dominated by bird-dispersed species, rather than mammal- or wind-dispersed species. Taken together, these results illustrate that disturbed areas with low initial on-site propagule availability have much potential for forest regrowth.     

Virus Transport Experiments in a Sandy Aquifer

The occurrence of human enteric viruses in ground water has been well documented in the literature. Bacteriophages such as MS-2 and PRD1 have properties similar to pathogenic human viruses suggesting that bacteriophages can be used as proxies for virus transport. The objective of this study is to investigate a “worst case scenario” for virus transport in a ground water aquifer, i.e., sand and gravel aquifer under a forced-gradient, by using bacteriophages. Field studies have been conducted to trace large-scale (34 m) and small-scale (10 m) virus transport under natural- and forced-gradients through a sand and gravel aquifer at a ground water research site at the Texas A&M University. Virus transport was monitored under natural and forced-gradient conditions using MS-2 and PRD-1 as virus tracers and bromide as a conservative tracer. Results indicate virus and bromide transport to down-gradient monitoring wells in both the large- and small-scale field tests. During the tests conducted, MS-2 transport appears to exhibit little longitudinal dispersion, showing a narrow peak at the well nest 34 m down-gradient in 13 days which is 20 days before the bromide breakthroughs, indicating that bacteriophage transport through the aquifer was mainly by advective flow. Differences in tracer transport can be attributed to the heterogeneity of the sand and gravel aquifer at the site, different injection methods, different sampling methods, and different tracer properties. Heterogeneity of the aquifer would cause virus transport through preferential flow paths.     

Epidemiological aspects of proliferative kidney disease amongst rainbow trout Salmo gairdneri Richardson in Northern Ireland

Abstract. The epidemiology of PKD is described as it relates to one affected farm in Northern Ireland. From 1972–1976 stocking and management practices led to mortality of 10–15% amongst the 0+fish. 1+or older fish were never affected. In 1977 and 1978, however, delaying the stocking of the farm until July eliminated deaths in the 0+fish, and mortality in these 1977-moved fish the subsequent year remained at an absolute minimum. Preliminary observations suggest that a means of controlling the disease has been found.
Experimental work demonstrates that the resistance of 1 +or older fish is due to previous exposure and is not an age-related immunity. Experimental work also suggests the presence of an incubation period of 6–7 weeks and that the peak time of infectivity is probably around May. None of the evidence detracts from the possibility that an infectious agent is involved although an attempt to transmit the disease failed.     

Effect of Distal Femoral Growth Plate Fusion on Femoral-Tibial Length

Unilateral distal femoral epiphysiodesis in seven 10 week old crossbred Doberman Pinscher littermates resulted in a significant (p less than or equal to 0.0001) femoral length deficit of 23.5% without clinically detectable alterations in gait up to 42 weeks after surgery. In addition to compensatory hyperextension of the stifle joint, the ipsilateral tibia showed significant (p less than or equal to 0.0001) acceleration in longitudinal growth. The combined femoral-tibial length at necropsy was still significantly shorter (p less than or equal to 0.0001) in the treated leg than in the control leg despite the increased tibial growth. Unlike other species, neither of the other two femoral growth plates produced any significant compensatory increase in length after fusion of the distal growth plate. The femoral condyles of the treated legs rotated caudally and degenerative joint disease developed in all stifle joints of the treated legs. No contralateral limb abnormalities were evident radiographically.     

Some observations on the dilution, cooling and freezing of canine semen

Canine semen was obtained by digital manipulation from two donor dogs and twelve stud dogs. The sperm-rich fraction was diluted with either of two different diluents and the survival of spermatozoa before and after freezing was determined. It appeared that there was no difference in the post-thaw survival rate in either of the diluents used.     

Histological effects of the inert suspended clay kaolin on the gills of juvenile rainbow trout, Salmo gairdneri Richardson

Abstract. Juvenile rainbow trout were exposed to 36, 171, 1017 and 4887 mg/1 of suspended kaolin clay for 64 days. Gills were analysed qualitatively and quantitatively using histology. Branchial pathology was absent at all sample times in fish exposed to 36, 171 and 1017 mg/1 kaolin, although intracellular kaolin was visible within filament and lamellar epithelium in gills exposed to 171, 1017 and 4887 mg/1 kaolin at 4, 8, 16, 32 and 64 days. Lesions were found in gills exposed to 4887 mg/1 kaolin at 16 and 32 days but the marked lamellar proliferation was associated with moderate to large numbers of protozoa identified as Ichthyobodo necator . Gills regained normal architecture by 64 days despite continued exposure to kaolin. It is suggested that while the gill lesions were probably a direct result of protozoan infection, kaolin was indirectly responsible for creating a favourable environment for protozoan colonization. The recovery of normal architecture and reduction of protozoan numbers between 32 and 64 days was probably a function of increased mucus secretion, immune response and turnover of branchial epithelium. The authors conclude that exposure to prevailing levels of this inert clay particle, even for periods as long as 64 days, probably has little direct effect on gill structure at the light microscope level. The action of non-inert and organic particles remains to be investigated.     

Pharmacokinetic and tissue distribution study of oxytetracycline in rainbow trout following bolus intravenous administration

Oxytetracycline pharmacokinetics and tissue distribution were studied in rainbow trout following bolus i.v. administration at 5 mg/kg. The mean serum (log) drug concentration data were plotted against time (linear). The decay curve was described by a three-component exponential decay function and a three-compartment model. The t1/2 of rapid distribution was 0.9 h, the t1/2 of the slow distribution was 5.9 h and the t1/2 elimination was 81.5 h. Clearance was 25.4 ml/kg/h and Vd(area) 2988 ml/kg. Regression analysis of the serum levels for the three intervals, 0.5-2.0 h, 6.0-18.0 h, and 24-96 h, indicated that the rates of decay for each interval were 0.6151 h-1, 0.0564 h-1 and 0.0088 h-1 respectively. Rates of equilibration between tissues and serum were determined. Kidney equilibrated the fastest with t1/2 to equilibration of 1.1 h for H (anterior) kidney and 1.98 h for P (posterior) kidney. The highest drug levels were found in the liver and the lowest were in the brain.