Descriptive epidemiology of small-bowel atresia in metropolitan Atlanta.

The epidemiological characteristics are presented of 46 children with small-bowel atresia, ascertained over a 6-year period by an active, population-based birth defect surveillance program in Atlanta, Georgia. The malformation occurred at a rate of 2.7/10,000 livebirths. The previously reported association of duodenal atresia and Down syndrome was confirmed was confirmed. No instances of familial association were noted, nor was any excessive prenatal exposure to drugs found. Thirty-two instances of isolated small-bowel atresia were analyzed in detail. The frequency of the isolated defect for blacks was twice that for whites because of a higher rate for black females. The isolated defect was commonest in the winter months. The relation between isolated small-bowel atresia, birth weight, and mortality was discussed. This small series cannot readily be subdivided into distinct epidemiological groups on the basis of the location of the atretic lesions along the length of the small bowel.     

Opportunistic zygomycotic infections

This is a literature review of 361 opportunistic fungal infections caused by the Zygomycetes. The clinical and laboratory diagnosis, pathogenesis, management, treatment, and outcome of infection are discussed. The Zygomycetes are a group of opportunistic fungi (orders Mucorales and Entomophthorales) which cause severe infections which may be fatal. Early clinical recognition, prompt diagnostic procedures, control of underlying disease and treatment with high doses of amphotericin B and aggressive surgery increases survival in an otherwise lethal infection.     

Identification of an amino acid substitution in the benA, beta-tubulin gene of Aspergillus nidulans that confers thiabendazole resistance and benomyl supersensitivity

We are using molecular genetic techniques to identify sites of interaction of beta-tubulin with benzimidizole anti-microtubule agents. We have developed a marker-rescue technique for cloning mutant alleles of the benA, beta-tubulin gene of Aspergillus nidulans and have used the technique to clone two mutant benA alleles, benA16 and benA19. These are the only A. nidulans alleles known to confer resistance to the benzimidazole antimicrotubule agent thiabendazole and supersensitivity to other benzimidazole antimicrotubule agents including benomyl and its active breakdown product, carbendazim. benA16 has been shown, moreover, to reduce thiabendazole binding to beta-tubulin. We have sequenced the two mutant alleles and have found that they carry different nucleotide changes that cause the same single amino acid substitution, valine for alanine at amino acid 165. Since thiabendazole and carbendazim differ at only one side chain, the R2 group, we conclude that the region around amino acid 165 is involved in the binding of the R2 group of benzimidazole antimicrotubule agents to beta-tubulin.     

Xylem and Phloem Import of Na+, K+, Rb+, Cs+ and Sb(SO4)2- in Tomato Fruits: Differential Contributions from Stem and Leaf

Wolterbeek, H. Th. and De Bruin, M. 1986. Xylem and phloem importof Na⁺, K⁺ , Rb⁺, Cs⁺ and in tomato fruits: differential contributions from stem and leaf.—J.exp. Bot. 37: 928–939. The transport of Na⁺, K⁺, Rb⁺, Cs⁺ and into developing fruits of tomato (an inbred lineof Lycopersicon esculentum Mill. cv. Tiny Tim) was measured.Element solutions were introduced into the transpiration streamthrough the cut stem bases of plant parts consisting of a stempart with single green fruit, both with and without attachedfully expanded leaf. Measurements were carried out of the accumulationin the fruit of the gamma-ray emitting radiotracers ²⁴Na⁺, ⁴²K⁺,⁸⁶Rb⁺, ¹³⁴Cs⁺ and The transport into the fruit was expressed by a single parameter taking intoaccount volume flows varying with time and experiments. Xylemto phloem transfer in the stem as a source of fruit elementsupply was shown to be inversely related with the velocity offlow of the stem xylem. The results also indicated that thetransfer system in the stem was more rapidly equilibrated thanit was in the leaf. Stem loading of the phloem is suggested as a possible mechanismregulating the solute influx in fruits under varying flow velocitiesof the stem xylem, while fruit influx of phloem solutes, whichwere loaded in the leaf, may play a major role in influx regulationunder conditions of varying solute concentrations. Key words: Alkali ions, tomato fruits, stem and leaf phloem loading     

Mitochondria and nuclei move by different mechanisms in Aspergillus nidulans

We have examined the effects of the antimicrotubule agent benomyl and several mutations on nuclear and mitochondrial movement in germlings of the filamentous fungus Aspergillus nidulans. While, as previously reported, benomyl inhibited nuclear division and movement, it did not inhibit mitochondrial movement. To test the effects of benomyl more rigorously, we germinated two benomyl super-sensitive, beta-tubulin mutants at a benomyl concentration 50-100 times greater than that required to inhibit colony formation completely. Again nuclear division and movement were inhibited, but mitochondrial movement was not. We also examined conditionally lethal beta-tubulin mutations that disrupt microtubule function under restrictive conditions. Nuclear division and movement were inhibited but, again, mitochondrial movement was not. Finally we examined the effects of five heat-sensitive mutations that inhibit nuclear movement but not nuclear division at restrictive temperatures. These mutations strongly inhibited nuclear movement at a restrictive temperature but did not inhibit mitochondrial movement. These data demonstrate that the mechanisms of nuclear and mitochondrial movement in Aspergillus nidulans are not identical and suggest that mitochondrial movement does not require functional microtubules.     

Changes in Abscisic Acid Content in Axis and Cotyledons of Developing Phaseolus vulgaris Embryos and their Physiological Consequences

Prevost, I. and Le Page–Degivry, M. Th. 1985. Changesin absicisic acid content in axis and cotyledons of developingPhaseolus vulgaris embryos and their physiological consequences.—J.exp. Bot. 36: 1900–1905.Changes in abscisic acid (ABA)content with time were measured in embryonic axes and in cotyledonsof Phaseolus vulgaris embryos using a radio–immunoassay.During embryogenesis, a similar pattern was observed in bothtissues: ABA increased to a maximum 29 d after an thesis, followedby a decrease as the seed matured. The level of ABA in the cotyledonswas always much higher than that in the axes. In in vitro cultures,the duration of the lag phase before germination of isolatedembryonic axes increased with ABA content. The presence of cotyledonsalways lengthened the lag phase; longer lag phases were associatedwith greater concentrations of ABA in the cotyledons. Moreoverthe presence of cotyledons stimulated the growth of seedlings. Key words: ABA distribution, embryo maturation, axis and embryo germinability     

Comparison of fiber types in skeletal muscles from ten animal species based on sensitivity of the myofibrillar actomyosin ATPase to acid or copper

Summary Comparisons were made of the histochemical characteristics of skeletal muscle from 10 animal species. The basic comparison was made from the staining patterns for the myofibrillar actomyosin ATPase produced by preincubation of fresh frozen cross-sections of muscle at alkaline pH (10.30) or acid pH (4.60) with those produced by preincubation in media containing Cu²⁺ at alkaline pH (10.30), near neutral pH (7.40), or acid pH (4.60). Muscle sections were also stained for reduced nicotinamide adenine dinucleotide tetrazolium reductase and alpha-glycerophosphate dehydrogenase to provide an indication of the relative oxidative and glycolytic capacity of the different fiber types. Type II fibers in mixed fibered muscles were either very sensitive, moderately sensitive, or relatively insensitive to inactivation of the myofibrillar actomyosin ATPase after acid preincubation. These fibers were identified as type IIA1, IIA2, and IIA3, respectively. The myofibrillar actomyosin ATPase of the type I fibers of these muscles, with the exception of those in mouse muscle, was activated by pretreatment with acid. A separation of animal species was possible based on the stability of the IIA1 fibers to inclusion of Cu²⁺ in the preincubation medium. For one group of animals (rat, mouse, monkey, man, dog, rabbit, and cow), a reciprocal relationship existed between lability to acid and stability to Cu²⁺ for type IIA1 and IIA3 fibers, respectively. For the second group of animals (horse, ass, and cat) there was a parallel relationship between lability or stability of the type IIA1 and IIA3 fibers to pretreatment with either acid or Cu²⁺ Visiting scholar from the Laboratory of Biomechanics and Physiology, College of General Education, Yamaguchi University, Yamaguchi 753, JapanSupported in part by Washington State Equine Research Program grant #105 3925 0042