Genotype frequencies associated with incompatibility systems in tristylous plants

A general procedure has been given previously for calculating frequencies of the morphs Long, Mid, and Short in equilibrium populations of tristylous plants. It is now demonstrated that an equilibrium state actually exists at the genotype level if this procedure produces admissible morph frequencies. This result holds in a diploid model, with or without linkage between the two loci involved. It is shown how the genotype frequencies may be determined for any set of mating probabilities. It is also explained how these frequencies may be calculated in a tetraploid model incorporating double reduction. The general theory is applied to a particular situation where the Mid morph is at a selective disadvantage as a seed parent.     

Phosphorylation of Tubulin by Casein Kinase II Regulates Its Binding to a Neuronal Protein (NP185) Associated with Brain Coated Vesicles

We recently described a new protein associated exclusively with neuronal clathrin-coated vesicles (CCVs), and characterized two monoclonal antibodies that react with it (S-8G8 and S-6G7). In this report, the association of neuronal protein of 185 kilodaltons (NP185) with CCV kinases and its interaction with tubulin are described. The affinity of NP185 for tubulin is significantly enhanced when tubulin is phosphorylated by CCV-associated casein kinase II. In contrast, phosphorylation of tubulin by a kinase activity associated with purified brain tubulin decreases its affinity for NP185. Together, these data suggest that the interaction of NP185 with tubulin is modulated by protein phosphorylation. Recent evidence has suggested that tubulin is phosphorylated by casein kinase II during neurite development. The enhanced affinity of NP185 for tubulin phosphorylated by casein kinase II could be important for proper intracellular sorting of this protein in the developing neuron.     

Laboratory animal allergy: an update

Allergic reactions are among the most common conditions affecting the health of workers involved in the care and use of research animals. Between 11 and 44% of the individuals working with laboratory animals report work-related allergic symptoms. Of those who become symptomatic, 4 to 22% may eventually develop occupational asthma that can persist even after exposure ceases. Allergic symptoms consist of rashes where animals are in contact with the skin, nasal congestion and sneezing, itchy eyes, and asthma (cough, wheezing, and chest tightness). The generation of immunoglobulin E (IgE) antibodies is a prerequisite for the production of allergic symptoms. The mechanism by which IgE antibodies develop is becoming clearer. The propensity to produce IgE is genetically determined, and pre-existing allergy may be a risk factor for the development of laboratory animal allergy (LAA). However, exposure to animal allergens is the major risk factor for the development of LAA. Techniques to measure the airborne concentration of laboratory animal allergens have been developed. Research on animal allergens themselves indicates that many of the mouse and rat urinary proteins belong to a family of proteins called lipocalins, which share sequence homology with antigens of the parasitic agent that causes schistosomiasis. The fact that parasite infections also trigger IgE antibody responses may account for the development of LAA in persons who have never had any previous allergy. The prevention of LAA should be a major goal of an effective health and safety program in the animal research facility, and it can be accomplished by education and training of employees, reduction of exposure (including the use of personal protective gear), and changes in facility design. Medical surveillance programs can also play a role in improving health of individuals working with laboratory research animals. Early recognition of symptoms and evidence of sensitization can lead to interventions to reduce exposure and thereby avoid the long-term health consequences of LAA.     

Traditional Ecological Knowledge of a Riverine Forest in Turkana, Kenya: Implications for Research and Management

The present study explores traditional ecological knowledge (TEK) of Turkana pastoralists and cultivators in the context of a riverine forest in northern Kenya. The Turkwel River and its floodplain sustain a thick forest, which is used for grazing and extraction of non-timber forest products. However, sedentarisation and agricultural expansion have resulted in localised clear-felling of trees, while river damming has altered the natural flow regime. A series of structured, semi-structured, and group interviews were combined with a botanical inventory in order to assess the relevance of TEK to ecological research and forest conservation. Turkana informants gave 102 vernacular names for the 113 woody species. Of these, 85% had a domestic or pastoral use among the 105 specific uses that were described. Ethnobotanical knowledge was relatively homogenous and not related to age, gender, or source of livelihood. The informants had in-depth knowledge of some key ecological processes. The conceived threats to forest survival were primarily cultivation and permanent settlements, while the effects of river damming and livestock grazing were disputed. A claimed decline in rainfall was confirmed by official data. There is strong evidence that TEK could be used to generate hypotheses for research and to design sustainable conservation strategies. A revised version of the indigenous system of tree management should be incorporated into the official forestry policy in order to resolve future conflicts between pastoralists and cultivators.     

Maternal and paternal contribution to intergenerational recurrence of breech delivery: population based cohort study

Objective To investigate intergenerational recurrence of breech delivery, with a hypothesis that both women and men delivered in breech presentation contribute to increased risk of breech delivery in their offspring.Design Population based cohort study for two generations.Setting Data from the medical birth registry of Norway, based on all births in Norway 1967-2004 (2.2 million births).Participants Generational data were provided through linkage by national identification numbers, forming 451 393 mother-offspring units and 295 253 father-offspring units. We included units where both parents and offspring were singletons and offspring were first born, forming 232 704 mother-offspring units and 154 851 father-offspring units for our analyses.Main outcome measure Breech delivery in the second generation.Results Men and women who themselves were delivered in breech presentation had more than twice the risk of breech delivery in their own first pregnancies compared with men and women who had been cephalic presentations (odds ratios 2.2, 95% confidence interval 1.8 to 2.7, and 2.2, 1.9 to 2.5, for men and women, respectively). The strongest risks of recurrence were found for vaginally delivered offspring and were equally strong for men and women. Increased risk of recurrence of breech delivery in offspring was present only for parents delivered at term.Conclusion Intergenerational recurrence risk of breech delivery in offspring was equally high when transmitted through fathers and mothers. It seems reasonable to attribute the observed pattern of familial predisposition to term breech delivery to genetic inheritance, predominantly through the fetus.     

Seedling establishment of Acacia tortilis and Hyphaene compressa in the Turkwel riverine forest, Kenya

This study reports on the spatial and temporal patterns of seedling establishment in the Turkwel riverine forest, Kenya. Seedlings of the dominant tree species Acacia tortilis and Hyphaene compressa were mapped and monitored to assess the underlying causes of seedling recruitment and mortality. The broad‐scale distribution of A. tortilis was not correlated with any environmental variables, while H. compressa seedlings were confined to flood‐exposed sites in the arid downstream section of the floodplain. One year of monitoring showed that seedling recruitment of A. tortilis was evoked by prolonged rainfall, while seedling mortality was caused by desiccation, browsing and trampling. In contrast, seedling recruitment and mortality of H. compressa was largely unaffected by rainfall and livestock, probably due to the high moisture requirements of seeds and the tolerance of seedlings to disturbance. There were no effects of soils, light, or seedling density on the establishment of A. tortilis and H. compressa seedlings. This study demonstrates the importance of parallel mapping and monitoring of riverine seedlings in order to understand patterns and processes of forest regeneration in arid and semi‐arid floodplains.     

ICE NUCLEATION IN SEAWEEDS IN RELATION TO VERTICAL ZONATION1

The ice nucleation temperatures of thallus fragments of different macroalgal species were investigated. The samples were collected from the littoral zone on a rocky shore in Trondheimsfjord, central Norway. Thallus fragments of species growing in the upper parts of the eulittoral zone had lower ice nucleation temperatures than those of species living in the lower eulittoral zone and in the upper sublittoral zone. Samples collected in the winter had lower nucleation temperatures than samples from the same species collected in the summer, which indicates that the seaweeds are removing or inactivating ice nucleators as a part of their cold hardiness strategy.     

Simulation and systems management in crop protection

Book Review

Simulation and systems management in crop protectionR. Rabbinge, S.A. Ward and H.H. van Laar (Eds.), (Simulation Monographs 32). Wageningen, The Netherlands: Centre for Agricultural Publishing and Documentation (Pudoc), 1989, xiv + 420 pages. Dfl. 125.00. ISBN 90-220-0899-1     

Factors affecting the chemiluminescent response of fish phagocytes

The effects of several factors on the phagocytic activity of cells isolated from the pronephros of striped bass, Morone saxatilis , were measured using a chemiluminescence (CL) assay. The CL responses of phagocytes to varying concentrations of bacteria, phorbol myristate acetate (PMA), and zymosan were shown to be dose-dependent. Incubation of phagocytes with PMA resulted in a decrease in cell numbers related to the concentration of PMA used in the assay. Opsonization of Aeromonas hydrophila with normal pooled bass serum decreased the number of colony forming units present in suspension while enhancing the CL response by striped bass phagocytes. Opsonization of zymosan also resulted in an enhanced CL response. Aeromonas hydrophila and Aerococcus viridans killed by heat treatment, incubation with formalin, or exposure to UV radiation elicited little or no CL when incubated with phagocytes.     

Occupational medicine programs for animal research facilities

Occupational medicine is a key component of a comprehensive occupational health and safety program in support of laboratory animal research and production facilities. The mission of the department is to maximize employee health and productivity utilizing a population health management approach, which includes measurement and analysis of health benefits utilization. The department works in close cooperation with other institutional health and safety professionals to identify potential risks from exposure to physical, chemical, and biological hazards in the workplace. As soon as exposures are identified, the department is responsible for formulating and providing appropriate medical surveillance programs. Occupational medicine is also responsible for targeted delivery of preventive and wellness services; management of injury, disease, and disability; maintenance of medical information; and other clinic services required by the institution. Recommendations are provided for the organization and content of occupational medicine programs for animal research facilities.