Salicyloylaspartate as an endogenous component in the leaves of Phaseolus vulgaris

An amide conjugate of o-methoxybenzoic acid and aspartic acid has been isolated from bean leaves. After extraction and methylation of plant material, this compound was isolated as two isomeric monoethyl monomethyl esters. The ethylation of the aspartyl carboxyl groups was shown to be a likely result of an extraction procedure utilising acidified ethanol, the methylation of the aromatic hydroxy of the methoxy group to be due to the derivatisation procedure. Studies with pentafluorobenzylation confirmed that the endogenous compound is o-hydroxybenzoylaspartate.     

Thermal environment and sudden infant death syndrome: case-control study.

OBJECTIVE--To compare the thermal environment of infants who died of the sudden infant death syndrome with that of age matched control infants. DESIGN--Case-control study. Infants who died were matched with two controls, one for age and one for age and birth weight. Thermal measurements were conducted at the death scene for cases and at the scene of last sleep for control infants, who were visited unexpectedly within four weeks of the index infant''s death on a day of similar climatic conditions. A follow up questionnaire was administered to parents of cases and controls. SETTING--The geographical area served by the professional Tasmanian state ambulance service, which includes 94% of the Tasmanian population. SUBJECTS--41 infants died of the sudden infant death syndrome at home; thermal observations at death scene were available for 28 (68%), parental questionnaire data were available for 40 (96%). 38 controls matched for age and 41 matched for age and birth weight. RESULTS--Cases had more excess thermal insulation for their given room temperature (2.3 togs) than matched controls (0.6 togs) (p = 0.009). For every excess thermal insulation unit (tog) the relative risk of the sudden infant death syndrome was 1.26 (95% confidence interval 1.05 to 1.52). The average thermal bedding value calculated from parental recall was similar to that observed by attendant ambulance officers (mean difference = 0.4 tog, p = 0.39). Cases were more likely to have been found prone (odds ratio 4.58; 1.48 to 14.11). Prone sleeping position was not a confounder or effect modifier of the relation between excess thermal insulation and the syndrome. CONCLUSIONS--Overheating and the prone sleeping position are independently associated with an increased risk of the sudden infant death syndrome. Further work on infant thermal balance and sudden infant death is required and guidelines for appropriate infant thermal care need to be developed.     

Generating lineage-specific markers to study Drosophila development.

To generate cell- and tissue-specific expression patterns of the reporter gene lacZ in Drosophila, we have generated and characterized 1,426 independent insertion strains using four different P-element constructs. These four transposons carry a lacZ gene driven either by the weak promoter of the P-element transposase gene or by partial promoters from the even-skipped, fushi-tarazu, or engrailed genes. The tissue-specific patterns of beta-galactosidase expression that we are able to generate depend on the promoter utilized. We describe in detail 13 strains that can be used to follow specific cell lineages and demonstrate their utility in analyzing the phenotypes of developmental mutants. Insertion strains generated with P-elements that carry various sequences upstream of the lacZ gene exhibit an increased variety of expression patterns that can be used to study Drosophila development.     

Simultaneous degradation of the herbicides 2,4-dichlorophenoxyacetic acid and 2-(2-methyl-4-chlorophenoxy)propionic acid by mixed bacterial cultures

The simultaneous degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-(2-methyl-4-chlorophenoxy)propionic acid (mecoprop) was achieved by two mixed cultures in the absence of any additional carbon or energy substrates. Mecoprop was not completely degraded by either of the two cultures, nor did addition of 2,4-D affect the degradation of mecoprop. The cultures completely degraded 2,4-D, and the degradation was uninfluenced by the addition of mecoprop. Nearly complete dechlorination of the mixture of two herbicides was achieved by both cultures, on the basis of the total amount of the two herbicides degraded. During the course of the reaction, however, the expected values of chloride were not met. Cell growth continued after the degradation of the parent substrates ceased. Although the mecoprop degradation did not continue to completion, spectral and growth data indicated that the metabolites which had accumulated during the reaction were degraded upon further incubation.     

Induction of protection against Brugia malayi infection in jirds by microfilarial antigens

The development of immunologic methods to reduce transmission of human lymphatic filariasis depends on measures that will enhance the host's ability to eliminate infective larvae, adult worms, or blood-borne microfilariae (mf). The present study was designed to assess the capacity of a crude extract of Brugia malayi mf to decrease the level of microfilaremia and adult worm burden in jirds inoculated with infective larvae, and to identify the filarial antigens that elicit antibody responses in these animals. Thirty weeks after subcutaneous inoculation with 75 infective larvae, 100% of control jirds were patent (i.e., had microfilaremia) compared with 60% of the group immunized with 10 micrograms of crude microfilarial extract (p less than 0.05). In addition, microfilaremia was lower in patent immunized animals compared with controls (p less than 0.05). The mean total number of adult female B. malayi per jird recovered at necropsy in control animals was 16.0 vs 7.0 in immunized jirds (p less than 0.05). Serum of immunized jirds contained anti-mf antibodies with an end titer of 1:8000, a value similar to that of animals with chronic B. malayi infection. Microfilarial antigens of Mr approximately 150,000, 75,000, 42,000, and 25,000 were identified in immunoblotting studies by reactivity with antibodies in sera of immunized jirds. Antibodies induced by immunization with microfilarial extract were not specific for this stage of the parasite life cycle, as jird anti-mf antibodies reacted with a Mr approximately 150,000 and several Mr 50,000 to 110,000 antigens derived from immature and mature adult parasites of both sexes. These data indicate that immunization of jirds with a water soluble microfilarial extract enhances the host's ability to eliminate adult worms and blood-borne mf. The filarial antigens that induce antibodies in immunized jirds have been identified.     

The crystal structure of d(G-G-G-G-C-C-C-C). A model for poly(dG).poly(dC)

The structure of the DNA oligomer d(G-G-G-G-C-C-C-C) has been determined at a resolution of 2.5 A by single-crystal X-ray methods. There are two strands in the asymmetric unit, and these coil about each other to form a right-handed double-helix of the A-type with Watson-Crick hydrogen bonds between base-pairs. The helix has a shallow minor groove and a deep, water-filled major groove; almost all exposed functional groups on the DNA are hydrated, and 106 ordered solvent molecules have been found. The two d(G-G-G-G).d(C-C-C-C) segments in the octamer exhibit similar and uniform structures, but there is a slight discontinuity at the GpC step between them. A recurring feature of the structure is the overlap of adjacent guanine bases in each GpG step, with the five-membered ring of one guanine stacking on the six-membered ring of its neighbour. There is little or no overlap between adjacent cytosine rings. Conformational parameters for these GpG steps are compared with those from other single-crystal X-ray analyses. In general, GpG steps exhibit high slide, low roll and variable twist. Models for poly(dG).poly(dC) were generated by applying a simple rotation and translation to each of the unmodified d(G-G-G-G).d(C-C-C-C) units. Detailed features of these models are shown to be compatible with various assays of poly(dG).poly(dC) in solution, and are useful in understanding the polymorphic behaviour of this sequence under a variety of experimental conditions.     

Some characteristics of monolayers of 1-palmitoyl-2-oleoyl-phosphatidylglycerol with and without dipalmitoylphosphatidylcholine during dynamic compression and expansion

Some properties of monolayers of $\text{1-}\text{palmitoyl}\text{-2-}\text{oleoyl}\text{-sn-}\text{glycero}\text{-3-}\text{phospho}\text{-rac-}\text{glycerol}$ (POPG) alone or of POPG in mixtures with $\text{1,2-}\text{dipalmitoyl}\text{-sn-}\text{glycero}\text{-3-}\text{phosphocholine}$ (DPPC) have been measured near 35°C during dynamic compression and expansion at 3.6 cm²·s^?1. (2) The mean values of minimum surface tension (corresponding to maximum surface pressure) which could be obtained with pure POPG monolayers at high compression ranged from 15 to 18 mN·m^?1 in the presence of Na⁺, Ca²⁺ or low pH (2.0) in the subphase. (3) The presence of Ca²⁺ or low pH in the subphase increased the collapse plateau ratios obtained on cyclic compression. This might represent enhanced respreading into the monolayer of pure POPG from a collapsed form during reexpansion of the surface. (4) Monolayers containing 10% or 30% POPG and 90% or 70% DPPC could be compressed to surface tensions approaching zero. (5) In such mixed monolayers, 10% or 30% POPG did not appear to enhance respreading, as measured by collapse plateau ratios, in the presence of Na⁺ or Ca²⁺ in the subphase.