Surface structures, co-aggregation and adherence phenomena of Streptococcus oralis and related species

Seven strains of Streptococcus oralis were found to possess surface structures. Four strains possessed long fimbriae which ranged in length from 266-366 nm, while the remaining three strains possessed shorter peritrichously distributed fibrils which ranged in length from 80-197 nm. The fibrillar strains were morphologically similar to strains of Streptococcus sanguis I and II and Streptococcus mitis. No strain of S. oralis produced tufts of fibrils like certain strains of S. sanguis I. Strains of Streptococcus milleri produced peritrichously distributed fimbriae which were morphologically dissimilar to the fimbriae produced by S. oralis strains. S. oralis strains were moderately to highly hydrophobic, but hydrophobicity could not be related to adhesion parameters or type or length or density of surface structures. Furthermore, there appeared to be no correlation between type of surface structures and adhesion parameters. Two of the three fibrillar strains of S. oralis and the peritrichously fibrillar strains of S. sanguis, together with one strain of S. milleri, were able to co-aggregate with actinomycetes.     

Effect of microspore stage and media on anther culture of peanut (Arachis hypogaea L.)

This study was designed to study the effects of stage of microspore development and culture medium on androgenic response in peanut (Arachis hypogaea L.). Anthers of various developmental stages were cultured for 7 days, then fixed and observed cytologically. Three sets of media, involving different basal media, growth regulators, sucrose levels and glutamine concentrations, were tested. In all experiments, the stage of development of the microspores at the time of culture was highly significant. The early uninucleate microspores stage was identified as producing the highest anther response rating. The effect of media was nonsignificant in all experiments. However, the stepwise modification of the media through the course of the study resulted in an almost 8 x increase in anther response rating. Numerically, the best media tested was N₆ basal medium with 1 mg 1^-1 NAA, 0.1 mg 1^-1 BA, 5.5% sucrose, and 3.5 g 1^-1 glutamine. While no haploids were obtained, four-nucleate cells were observed, indicating the potential in peanuts for an androgenic reponse.     

Morbidity in Chagas' disease. IV. Longitudinal study of 10 years in Pains and Iguatama, Minas Gerais, Brazil

An evolutive study of the "case-control" type was carried out in an endemic area of Chagas' disease in Minas Gerais State, Brazil, using two cross-section evaluations with an interval of ten years between them (1974-1984). Patients were paired for sex and age. In the first cross-section study 264 pairs one with a positive serology and the other with a negative serology for T. cruzi antibodies were included. In the second evaluation, ten years later, 235 patients among those with previous positive serology and 216 with negative serology were located, but only 110 pairs could be recomposed and reexamined (clinical examination, ECG and Rx of the heart and esophagus). The incidence of chagasic cardiopathy in the cases with positive serology but previously assymptomatic was 38.3% during the ten year period. On the other hand there was a deterioration in 24% of the patients with chagasic cardiopathy since the first examination. Considering all clinical forms of the disease in 34.5% of the patients the clinical situation deteriorated, in 57.3% there was no change and in 8.2% the situation improved. The general mortality in the period was 23% in the chagasic group and 10.6% in the control group, but the lethality by cardiopathy was 17% in chagasic group and only 23.3% in the control group. The mortality was twice as high in males than in females, mainly in the age group from 30 to 59 years.     

Two binding proteins for progesterone in the bovine corpus luteum

The cytosolic supernatant of bovine corpus luteum contains two proteins which bind progesterone specifically. Bovine luteal cytosol was fractionated on hydroxylapatite and the peaks of protein obtained subjected to equilibrium dialysis against progesterone. Progesterone-binding activities (Ka approx. 10(6) 1/mol) was eluted at 40 mM (Binding Protein 1) and 100 mM phosphate (Binding Protein 2). They sedimented differently (3.95 and 4.65, respectively) on sucrose gradients. In contrast to Binding Protein 1, Binding Protein 2 bound R5020 better than progesterone on sucrose gradients. Purification of the binding activity eluted by 40 mM phosphate from the hydroxylapatite column showed that it resided in a single protein (molecular weight 65,000 daltons). The function of these proteins is presently unknown, but they may participate in the biosynthesis and/or secretion of progesterone from bovine luteal cells.     

Evidence for plant exploitation and vegetation history from three Early Neolithic pre-pottery sites on the Euphrates (Syria)

Archaeobotanical results based on a limited number of samples from three aceramic sites dating from 9800 to 7800 B.P., which are under excavation in the valley of the Middle Euphrates, are discussed. The finds are presented simply by presence, and are compared to the contemporary vegetation and finds from similar sites. Carbonised plant remains recovered by flotation from levels dated to between 9800 and 9200 B.P. (Dja'de and Jerf al Ahmar) indicate that wild cereals (einkorn wheat, rye and barley) and pulses (lentils, pea and bitter vetch) were exploited. Other plants such as wild grasses, Pistacia, wild almond and oak, suggest that the local vegetation provided a rich diversity of resources. A study of possible weed taxa is being carried out in order to see whether this assemblage could be used to identify the cultivation of morphologically wild cereals for this period. Ninth millennium B.P. levels at Halula see the appearance of domestic crops such as emmer, naked wheat and barley, but wild-type cereals persist. The cultivars appear to have been introduced from elsewhere and later ninth millennium B.P. species include olive and flax. Ash, vine, maple, plane, alder and elm from the gallery forest, wild rye, wild einkorn, deciduous oak, wild almond, Pistacia, and Pyrus, from the hinterland, indicate cooler conditions.     

Total and free plasma concentrations of progesterone, cortisol and oestradiol-17 beta during pregnancy, parturition and early lactation in sows

The total (bound plus free) concentrations of progesterone, 20 alpha-dihydroprogesterone, oestradiol-17 beta and cortisol were determined in the plasma of sows at three stages during pregnancy and more intensively from 5 days pre-partum to 5 days post-partum. The free fractions of progesterone, oestradiol-17 beta and cortisol were measured in the same samples by a rate dialysis method. Up to day 110 of gestation, the amounts of free hormone in plasma did not fluctuate independently of their total concentrations. During farrowing, the total and free concentrations of progesterone and cortisol varied independently of each other, whereas total and free oestradiol-17 beta declined simultaneously. The initiation of parturition was associated with a decrease in circulating total progesterone, and was accentuated by a decrease in the free fraction (P less than 0.005) so that its active free concentration was only 20% of its day 1 pre-partum value. Total and free cortisol concentrations rose rapidly during labour so that at 12-18 h after birth of the first piglet 30% of that cortisol in maternal plasma was free hormone.     

MICROSPOROGENESIS IN PEANUT (ARACHIS HYPOGAEA)

The stage of pollen development at the time of anther culture is an important factor in the production of haploids. The objectives of the current study were to develop a staining procedure for peanut (Arachis hypogaea L., ssp. hypogaea) microspores, to describe and document the stages of microsporogenesis in peanut, and to confirm a previous report concerning correlations of peanut floral bud shape with stage of microspore development. A staining procedure using propionic carmine provided adequate staining of pollen mother cells, microspores, and pollen. Pollen mother cells and microspores could easily be differentiated by their size and cell wall structure. Plants grown in a controlled environment were found to have highly synchronized microspore development, both within an anther and among anthers contained in the same bud. In addition, floral bud shape was confirmed as a reliable indicator of anther stage in peanuts.     

Synthesis,characterization and in vitro activity of a surface-attached antimicrobial cationic peptide

Infection associated with implanted biomaterials is common and costly and such infections are extremely resistant to antibiotics and host defenses. Consequently, there is a need to develop surfaces which resist bacterial adhesion and colonization. The broad spectrum synthetic cationic peptide melimine has been covalently linked to a surface via two azide linkers, 4-azidobenzoic acid (ABA) or 4-fluoro-3-nitrophenyl azide (FNA), and the resulting surfaces characterized by X-ray photoelectron spectroscopy and contact angle measurements. The quantity of bound peptide was estimated by a modified Bradford assay. The antimicrobial efficacy of the two melimine-modified surfaces against Pseudomonas aeruginosa and Staphylococcus aureus was compared by scanning electron microscopy (SEM) and fluorescence microscopy. Attachment of melimine via ABA gave an approximately 4-fold greater quantity of melimine bound to the surface than attachment via FNA. Surfaces melimine-modified by either attachment strategy showed significantly reduced bacterial adhesion for both strains of bacteria. P. aeruginosa exposed to ABA–melimine and FNA–melimine surfaces showed marked changes in cell morphology when observed by SEM and a reduction of approximately 15-fold (p < 0.001) in the numbers of adherent bacteria compared to controls. For the ABA–melimine surface there was a 33% increase in cells showing damaged membranes (p = 0.0016) while for FNA–melimine there was no significant difference. For S. aureus there were reductions in bacterial adhesion of approximately 40-fold (p < 0.0001) and 5-fold (p = 0.008) for surfaces modified with melimine via ABA or FNA, respectively. There was an increase in cells showing damaged membranes on ABA–melimine surfaces of approximately 87% (p = 0.001) compared to controls, while for FNA–melimine there was no significant difference observed. The data presented in this study show that melimine has excellent potential for development as a broad spectrum antimicrobial coating for biomaterial surfaces. Further, it was observed that the efficacy of antimicrobial activity is related to the method of attachment.