The effect of food deprivation on enzyme activity in developing brain

Brain and body weights, contents of DNA and protein and activities of 1,6-diphosphofructoaldolase (aldolase, EC 4.1.2.13), creatine phosphokinase (CPK, EC 2.7.3.2), and isocitric dehydrogenase (ICD, EC 1.1.1.42) in brain (minus cerebellum and brain stem) were studied in control and food-deprived rats at 7, 14 and 21 days of postnatal age. Activities of all three enzymes per brain were less in the food-deprived animals. In both groups of rats the ratios of aldolase/DNA and CPK/DNA increased with maturation, indicating that increasing activity per brain during maturation was the result of both increased activity per cell and increased numbers of cells. The ratio of ICD/DNA decreased with maturation but was essentially the same in both the food-deprived and control groups. Increase of ICD activity per brain with maturation was attributable to increased numbers of cells. Food deprivation in immature animals resulted in lowered activities per brain for aldolase, CPK and ICD because of diminished cell multiplication.     

Assessing the promise of user involvement in health service development: ethnographic study

Objectives To understand how the policy of user involvement is interpreted in health service organisations and to identify factors that influence how user involvement is put into practice.Design Ethnographic study using participant observation, interviews, and collection of documentary evidence.Setting A multiagency modernisation programme to improve stroke services in two London boroughs.Participants Service users, National Health Service managers, and clinicians.Results User involvement in the programme was initiated and led by professionals. Professionals determined the areas of service improvement service users could participate in. A wide range of activities were considered “user involvement,” from patient satisfaction surveys to service users delivering peer support. Involvement tended to be most active in the least technical areas and areas with least input from clinicians. Factors that might explain this included organisational structure, the vagueness of the concept of user involvement, the value attributed to service users’ experiential knowledge, and variations in professional and service user understandings of and commitment to involvement. The gains of involvement were harder to identify in terms of impact on services. More evident were the personal gains for those involved: satisfaction of feeling listened to by professionals, social opportunities of meeting others in a similar situation, and increased knowledge about stroke and services available.Conclusions User involvement may not automatically lead to improved service quality. Healthcare professionals and service users understand and practise user involvement in different ways according to individual ideologies, circumstances, and needs. Given the resource implications of undertaking user involvement in service development there is a need for critical debate on the purpose of such involvement as well as better evidence of the benefits claimed for it.     

Safety of chloroquine in chemosuppression of malaria during pregnancy.

A cohort of 169 births to women who were exposed throughout pregnancy to chloroquine 300 mg base once a week for chemosuppression of malaria was studied. The birth defects in this cohort were compared with those in a control group of 454 births to women who were not exposed to chloroquine, most of whom lived in non-malarious areas. The proportion of birth defects in the exposed group was not significantly different from that in the control group. This observation must be considered within the limitations of the study, which could detect only a strong teratogenic effect. It could not exclude risks lower than a 5.7-fold increase in the incidence of birth defects when chloroquine was used. Women using chloroquine during pregnancy for chemosuppression of malaria can be reassured that it is not a strong teratogen, but if it is to be used the risk of developing malaria should be balanced against the lack of data to determine whether it carries a low teratogenic risk.     

Do pollen beetles need pollen? The effect of pollen on oviposition,survival, and development of a flower‐feeding herbivore

Abstract.  1. Pollen is considered to be an important dietary component for many species of flower-feeding herbivores. Its influence on oviposition site selection by the pollen beetle Meligethes aeneus , and on the development of its larvae was investigated.
2. The effects of pollen presence and absence on adult, egg, and larval incidence in the field, and on larval development in the laboratory were compared through the use of Synergy, a composite hybrid oilseed rape Brassica napus variety comprising male-fertile (with pollen) and male-sterile (without pollen) plants.
3. In the field, adult females were more abundant on male-fertile plants during flowering, and a greater proportion of male-fertile than male-sterile buds were accepted for oviposition. These data indicate a possible role of pollen in oviposition site selection by female pollen beetles.
4. The numbers of first instar larvae on the two plant lines did not differ; however, more second instars were found on male-fertile than on male-sterile flowers. This suggests a greater larval survival on male-fertile plants, possibly due to the more readily available food resources and better nutrition afforded by the presence of pollen.
5. Laboratory experiments confirmed that a diet which included pollen improved survival to adulthood and resulted in heavier pupae and adults; however, pollen was not obligatory for larval survival and development.
6. The pollen beetle, previously thought to be an obligate pollen feeder, is therefore more generalist in its requirements for development. These findings may relate to the nutritional and behavioural ecology of other flower-feeding herbivores.     

Behavior ofPseudomonas fluorescens within the hydrodynamic boundary layers of surface microenvironments

Phase, darkfield, and computer-enhanced microscopy were used to observe the surface microenvironment of flow cells during bacterial colonization. Microbial behavior was consistent with the assumptions used previously to derive surface colonization kinetics and to calculate surface growth and attachment rates from cell number and distribution. Surface microcolonies consisted of closely packed cells. Each colony contained 2ⁿ cells, where n is the number of cell divisions following attachment. Initially, cells were freely motile while attached, performing circular looping movements within the plane of the solid-liquid interface. Subsequently, cells attached apically, maintained a fixed position on the surface, and rotated. This type of attachment was reversible and did not necessarily lead to the formation of microcolonies. Cells became irreversibly attached by progressing from apical to longitudinal attachment. Longitudinally attached cells increased in length, then divided, separated, moved apart laterally, and slid next to one another. This resulted in tight cell packing and permitted simultaneous growth and adherence. After approximately 4 generations, individual cells emigrated from developing microcolonies to recolonize the surface at new locations. Surface colonization byPseudomonas fluorescens can thus be subdivided into the following sequential colonization phases: motile attachment phase, reversible attachment phase, irreversible attachment phase, growth phase, and recolonization phase.     

Synthesis of 7-mercaptoheptanoylthreonine phosphate and its activity in the methylcoenzyme M methylreductase system

The structure of component B of the methylcoenzyme M methylreductase of Methanobacterium thermoautotrophicum was recently assigned as 7-mercaptoheptanoylthreonine phosphate (HS-HTP) (Noll, K. M., Rinehart, K. L., Jr., Tanner, R.S., and Wolfe, R.S. (1986) (Proc. Natl. Acad. Sci. U.S.A. 83, 4238-4242). We report here the chemical synthesis and biochemical activity of this compound. Thiourea and 7-bromoheptanoic acid were used to to synthesize 7,7'-dithiodiheptanoic acid. This disulfide was then condensed with DL-threonine phosphate using N-hydroxysuccinimide and dicyclohexylcarbodiimide. The product was reduced with dithiothreitol to give HS-HTP. It could be oxidized in air in the presence of 2-mercaptoethanol to give the compound as it was isolated from cell extracts. The resulting product was identical to the authentic compound by 1H NMR spectroscopy, mass spectrometry, and coelution using high performance liquid chromatography. The synthetic compound is active in the in vitro methanogenic assay at concentrations comparable to the authentic compound. This confirms the structure of component B as HS-HTP and provides a means to synthesize quantities sufficient for studies of the methylreductase system.     

Evidence for African origins of founders of the asiatic lion species survival plan

The Asiatic lion (Panthera leo persica) exists in the wild as a single relict population of approximately 250 individuals in the protected Gir Forest Sanctuary in western India. In 1981, a species survival plan (SSP) for the Asiatic lion was established by the American Association of Zoological Parks and Aquariums to manage the 200 + descendants of Asiatic lions in captivity in western zoological facilities. This captive population was derived from seven founders. In order to compare the genetic structure of the Gir Forest population with that of the captive SSP population, a genetic survey of 46 electrophoretic allozyme systems resolved from extracts of lion blood was undertaken by using 29 SSP Asiatic lions and 28 wild-caught or captive-bred lions maintained at the Sakkarbaug Zoo in India but originally derived from the Gir Forest. The Gir lion population was found to be genetically monomorphic at each of 46 allozyme loci. This was in contrast to several African lion (Panthera leo leo) populations, which show moderate levels of allozyme variation at the same loci. The SSP lion population was polymorphic at three allozyme loci (IDHI, TF, and PTI) for alleles that were previously found only in African lion populations. Pedigree analysis of the genetic transmission of these three biochemical loci demonstrated that two of the five primary founder animals of the SSP Asiatic lion population (a breeding pair originally imported from the Trivandrum Zoo in southern India) were descendants of the African subspecies. Three other founder animals were pure Asian. A retrospective SSP pedigree analysis of two morphologic characters (prominent abdominal fold and pairing of infraorbital foramen) that are partially diagnostic for persica vs leo was consistent with this conclusion as well. The implications for the management of small captive populations of threatened species and of the Asiatic lion SSP population are discussed.