Accumulation of mansonones E and F in seedlings of Ulmus americana in response to inoculation with Ophiostoma ulmi

Summary The accumulation of mansonones E and F was investigated in Ulmus americana L. seedlings 5 weeks after inoculation with three aggressive and three non-aggressive isolates of Ophiostoma ulmi (Buism.) Nannf. The three non-aggressive isolates stimulated significantly more mansonone E and F accumulation than the three aggressive isolates of O. ulmi. Mansonone induction also varied within both the aggressive and the non-aggressive groups. Aggressive and non-aggressive isolates were recovered in equal frequencies from the inoculation wounds, whereas the aggressive isolates were recovered more frequently than the non-aggressive isolates 15 cm and 25 cm up the seedlings' stem. Vascular browning in the outer xylem of the seedlings correlated with mansonone E and F accumulation. Mansonone accumulation in U. americana seedlings is therefore associated with vascular browning and a reduction in fungal spread.     

Facilitating care of patients with HIV infection by hospital and primary care teams.

To complement the role of primary care teams working with patients with HIV disease and AIDS within greater London and to ease the load on the special hospital units a home support team was developed. It comprises six specialist nurses, a general practitioner trained medical officer, and a receptionist and is funded from regional and district sources and charities. A nurse is available for out of hours and emergency weekend calls, with support from the patient''s general practitioner or the attached medical officer. During the first 18 months 249 patients were seen; the mean duration of care was five months. Nearly a third (18/50, 30%) of patients who were terminally ill died at home. The team''s activities included practical nursing care, emotional support for carers and patients, and advice and guidance to primary care teams. Problems in providing care in patients'' homes included issues relating to confidentiality and 24 hour cover. With the increasing incidence of HIV infection the home support team may be a useful model for care of large numbers of patients with symptomatic HIV disease, especially in large urban areas.     

Catabolism of dl-α-phenylhydracrylic,phenylacetic and 3- and 4-hydroxyphenylacetic acid via homogentisic acid in a Flavobacterium sp.

A degradation pathway for dl--phenylhydracrylic, phenylacetic, 3- and 4-hydroxyphenylacetic acid by a Flavobacterium is presented. Experiments with washed cells and enzyme studies revealed that dl--phenylhydracrylic acid in an initial reaction was oxidatively decarboxylated to phenylacetaldehyde. Whole cells oxidized both stereoisomers of phenylhydracrylic acid at different rates. The product phenylacetaldehyde in turn was oxidized to phenylacetic acid. No hydroxylation of phenylacetic acid was detected in cell extracts, but on the basis of experiments with washed cells it is assumed that phenylacetic acid is mainly metabolized via 3-hydroxyphenylacetic acid. This latter product was subsequently hydroxylated yielding the ring-cleavage substrate homogentisate. 4-Hydroxyphenylacetic acid was also degraded via homogentisate. Ringcleavage of homogentisate gave maleylacetoacetate which was further degraded through a glutathione-dependent pathway. Homoprotocatechuate was not an intermediate in the metabolism of dl-phenylhydracrylic acid, phenylacetic, 3- and 4-hydroxyphenylacetic acid metabolism, but it could be hydroxylated aspecifically to 2,4,5-trihydroxyphenylacetic acid by the action of the 3-hydroxyphenylacetic acid-6-hydroxylase.Abbreviations HPLC high-performance liquid chromatography - PHA phenylhydracrylic acid - PA phenylacetic acid - HPA hyxdroxyphenylacetic acid - PMS phenazine methosulphate - PMA phenylmalonic acid - GSH glutathione     

Further resolution of the low density lipoprotein spectrum in normal human plasma: physicochemical characteristics of discrete subspecies separated by density gradient ultracentrifugation

The molecular basis of the heterogeneity of plasma low density lipoproteins (LDL, d 1.024-1.050 g/ml) was evaluated in 40 normolipidemic male subjects following fractionation by isopycnic density gradient ultracentrifugation into eight major subspecies. The mass profile of our subjects' LDL uniformly displayed single symmetric or asymmetric peaks as a function of density; the peak occurred most frequently (20 subjects) in subfraction 7 (d 1.0297-1.0327 g/ml). Several physicochemical properties (hydrodynamic behavior, electrophoretic mobility, chemical composition, size and particle heterogeneity, and apolipoprotein heterogeneity) of the LDL subfractions were examined. Hydrodynamic analyses revealed unimodal distributions and distinct peak Sf degree rates in individual subfractions. Such behavior correlated well with particle size and heterogeneity data, in which LDL subspecies were typically resolved as unique narrow bands by gradient gel electrophoresis. Subspecies with average densities of 1.024 to 1.0409 g/ml ranged from 229 to 214 A in particle diameter. LDL protein content increased in parallel with density while the proportion of triglyceride diminished; cholesteryl esters predominated, accounting for approximately 40% or more by weight. Distinct differences in net electric charge were demonstrated by electrophoresis in agarose gel, the subspecies with average density of 1.0314 g/ml displaying the lowest net negative charge. ApoB-100 was the major apoprotein in all subspecies, and constituted the unique protein component over the density interval 1.0271-1.0393 g/ml. ApoE and apo[a] were detected at densities less than 1.0271 and greater than 1.0393 g/ml. While apoE was evenly distributed within these two regions, representing up to 2% of apoLDL, the distribution of apo[a] was skewed towards the denser region, in which it amounted to 3-7% of apoLDL. ApoC-III was detectable as a trace component at densities greater than 1.0358 g/ml. Calculation of the number of molecules of each chemical component per LDL subspecies showed the presence of one copy of apoB-100 per particle, in association with decreasing amounts of cholesteryl ester, free cholesterol, and phospholipid. These data indicate that a similar overall molecular organization and structure is maintained in a unimodal distribution of LDL particle subspecies over the density range approximately 1.02 to 1.05 g/ml. In sum, our data may be interpreted to suggest that microheterogeneity in the physicochemical properties of human LDL subspecies reflects dissimilarities in their origins, intravascular metabolism, tissular fate, and possibly in their atherogenicity.     

Circadian and Ultradian Rhythms in Blood Glucose and Plasma Insulin of Healthy Adults

The circadian and ultradian variations of blood glucose and plasma insulin have been characterized individually and as a group phenomenon in five healthy young adults studied while adhering as closely as possible to their usual routine of sleep, activity, meal content and timing. Three complementary methods were used to analyze the data: displaying raw data as a function of time; cosinor method according to Nelson and Halberg; and time series analyses as proposed by De Prins and Malbecq. The subjects were studied in the laboratory and their life routine were controlled, but very close to that of their habitual routine. They had mainly ultradian rhythms of blood glucose (mainly about 6 hr) and circadian rhythms of immunoreactive insulin (I.R.I.). Blood glucose ultradian rhythms seem to be mainly but not exclusively mealtime dependent, while I.R.I, circadian rhythms appear to be primarily endogenous in origin. Therefore, the role played by insulin in the control of blood glucose levels seems to be programmed on a circadian basis rather than by a time independent feedback phenomenon as postulated by the conventional homeostatic hypothesis. The advantage of this chronophysiologic approach is to consider circadian rhythms of both I.R.I. and insulin effectiveness as an adaptive phenomenon able to maintain blood sugar changes in the ultradian domain of rhythms.     

Sugars fermented byBifidobacterium infantis ATCC 27920 in relation to growth and α-galactosidase activity

Summary The ability of Bifidobacterium infantis ATCC 27 920 to ferment glucose, galactose, lactose, melibiose and raffinose was investigated with respect to -galactosidase (-d-galactoside galactohydrolase, E.C. 3.2.1.22). The sugars were tested at three concentrations: 0.5, 1.0 and 2.0%. The growth of B. infantis was slower on glucose compared with the other sugars. The highest specific growth rate was observed on melibiose followed by lactose. High cell numbers could be rapidly obtained on galactose-containing sugars. For each carbohydrate, enzyme activity was maximal at the end of the exponential phase and the highest specific -galactosidase activities were recorded on the two -1,6 galactosaccharides (melibiose and raffinose: 3.0 and 4.5 nkat · 10⁹ colony-forming units, respectively).Contribution no. 186 from the Food Research and Development Centre Offprint requests to: D. Roy     

Expedient syntheses of neoglycoproteins using phase transfer catalysis and reductive amination as key reactions

Starting from peracetylated chloro- or bromo-glycosyl donors ofN-acetylneurmainic acid,N-acetylglucosamine, glucose and lactose, the correspondingp-formylphenyl glycosides were synthesized stereospecifically under phase transfer catalysed conditions at room temperature in yields of 38–67%. After Zemplén de-O-acetylation, the formyl groups were directly and chemoselectively coupled to the lysine residues of bovine serum albumin by reductive amination using sodium cyanoborohydride. The conjugation reactions were followed as a function of time and under a series of different molar ratios of the reactants to provide glycoconjugates of varying degree of antigenicities. Thus, carbohydrate protein conjugates were made readily available using essentially two key reactions.Presented in part at the 15th International Carbohydrate Symposium, Yokohama, Japan, August 12–17, 1990.     

Two different sets of cis elements regulate scute to establish two different sensory patterns

Summary We have analysed the role of the achaete-scute gene complex in the development of the pattern of campaniform sensilla on the wing blade of Drosophila. We show that the complete pattern results from the superimposition of two independent subpatterns, one of which depends on the achaete gene and the other on scute. The scute subpattern comprises several clusters of sensilla, most of which seem to require the presence of control regions located upstream of the transcribed region. This is in contrast with the pattern of scute-dependent bristles, most of which depends on control elements located downstream of the transcribed region.