Ecological life histories of the three aquatic nuisance plants,Myriophyllum spicatum,Potamogeton crispus and Elodea canadensis

The life histories of Myriophyllum spicatum L., Elodea canadensis Michx., and Potamogeton crispus L., serious aquatic nuisances in many regions of the world, are reviewed to provide insights into the life style of successful aquatic nuisance plants. Specifically, their distribution and spread in North America; their life cycle, productive and reproductive potential; and their ecosystem relationships are reviewed. Hopefully this review will improve a manager's ability to deal with aquatic nuisance problems. It also provides suggestions for basic research needed to develop more effective management practices.It was found that all three species possess a number of adaptations, including an ability to rapidly propagate vegetatively, an opportunistic nature for obtaining nutrients, a life cycle that favors cool weather, and a number of mechanisms which enhance photosynthetic efficiency, which allow them to proliferate.These three species do provide benefits to the ecosystem through their roles in materials cycling and energy flow. Therefore, management of these species should take an integrated approach which recognizes these benefits.The life history information available about the three species varies tremendously; however, a better understanding of resource gain and allocation is needed to manage all three species. Specifically, more research is needed to provide a better understanding of: 1) the role bicarbonate plays in photosynthesis, 2) the role roots play in supplying CO₂ to the plabts, 3) resource accumulation and allocation under different temperature and light regimes, 4) resource allocation on a seasonal basis, and 5) nutrient cycling under different management regimes.     

An improved procedure for the preparation of alkyl sulphate esters suitable for the study of secondary alkylsulphohydrolase enzymes.

A simple, rapid and convenient method for the synthesis of secondary alkyl sulphate esters is described in which the sodium alkoxide of the parent alcohol is sulphated by using triethylamine-SO3 complex. The procedure gives relatively good yields, even for the sulphation of long-chain alcohols and those in which the hydroxy group is remote from the terminal carbon atoms. Positional isomerization, arising from the migration of the hydroxy group along the carbon chain, is absent, and resolved enantiomers of alcohols react with complete retention of configuration.     

R Factors in Hospital Infection

In order to assess the clinical importance of R factors 524 “coliform” infections were studied in a general hospital. Of these, 95 were caused by Pseudomonas aeruginosa. Among the remaining 429, 43% were caused by drug-resistant enterobacteria; resistance was frequently multiple and determined by transmissible R factors. Choice of therapy was thus limited but in every case at least one antibiotic, effective in vitro, was still available.     

Release of prostaglandin from rat epididymal fat pad on nervous and hormonal stimulation

Acidic lipids with smooth muscle-stimulating properties were extracted from rat epididymal fat pads and were shown to co-chromatograph with (PGE1) prostaglandin E1, PGE2, and PGF2alpha. Further chemical identification was not possible with the small amounts of material available. A basal efflux of PGE and PGF compounds was observed following incubation of adipose tissue in vitro. Increased efflux of PG was detected under conditions reported to enhance free fatty acid release, i.e., addition of lipolytic hormones or drugs to the incubating medium, prior fasting of the animal, or stimulation of the epididymal nerve. These results, together with a decreased release of PG-like material in the presence of insulin, suggested that the efflux may be associated with lipolysis resulting from activation of a hormone-sensitive lipase. Since the PGs are known to affect the concentration of cyclic adenosine 3', 5'-monophosphate in adipose tissue, and this nucleotide is an intermediary in hormone-stimulated lipolysis, it is possible that the PGs released may serve to maintain the homeostasis of adipose tissue by way of a physiological feedback control mechanism.     

Chromosome number in the lizard genus Uta (family Iguanidae)

A chromosome number of 34 (12 macro- and 22 microchromosomes) was found to be characteristic of the bone marrow in 47 animals including males from the species Uta antiquus, and both males and females from the following species and subspecies: Uta stansburiana stansburiana, Uta stansburiana stejnegeri, Uta stansburiana elegans, Uta stansburiana klauberi, Uta stansburiana mannophorus, Uta nolascensis, Uta palmeri, and Uta squamata. — Diploid chromosome numbers of 34 and haploid numbers of 17 were found in the nine testis smears examined. — The presence of a large number of hypodiploid figures in the bone marrow smears is attributed to cell fragmentation and the problem of distinguishing the small microchromosomes. — Series of polyploid figures whose chromosome numbers increased in arithmetic rather than geometric progressions were observed in the testis dry smears. Possible alternatives for the origin of these figures are presented. — Problems encountered in the use of chromosome number as a taxonomic character are discussed.Supported in part by Research Grants GB-366 and GB-5416 from the National Science Foundation, and GM-15361 from the United States Public Health Service.     

POLIOMYELITIS IN PREGNANCY

Acute poliomyelitis occurs in all trimesters of pregnancy. At one time there were six women in the poliomyelitis ward at Children''s Hospital, five of whom were either pregnant or recently delivered. Poliomyelitis is an important entity in the differential diagnosis of diseases complicating pregnancy. Once diagnosed, treatment is directed primarily toward the symptoms of poliomyelitis, secondarily toward pregnancy. Effort should be made to maintain adequately high oxygen tension in the maternal blood stream to protect the fetus. The prognosis of the disease when it occurs during pregnancy may be less predictable, but it is generally good for both mother and infant. Although the incidence of abortion is relatively high, if the pregnancy goes to term parturition is expected to be normal. The number of cases reported is not sufficient to establish the significance of the suspected selective occurrence of poliomyelitis in pregnancy.