Polyploidy and habitat differentiation in Dactylis glomerata L. from Galicia (Spain)

Summary The microdistribution of diploid and tetraploid plants of Dactylis glomerata L. was examined and related to their immediate environment in several sites in central Galicia, where morphologically indistinguishable individuals of both ploidies grow in sympatry. The two related cytotypes differed in habitat preference. Diploids were mainly confined to the low-density forest-floor habitat in woodlands of mostly ancient origin, whereas tetraploids were widespread in varied habitats but clearly predominant in open areas, particularly in disturbed anthropic sites. The in situ comparison of plant performance showed that where plants of each ploidy were more common they produced more tillers, panicles and seeds. This habitat preference closely reflected differences in life-history characteristics. The tetraploids had an early and short flowering time almost always completed before the aestival drought, whereas the diploids began to flower several weeks later and flowered throughout the drought. Comparisons along artificial gradients of soil water availability and light transmittance indicated that the cytotypes had distinct physiological requirements which probably originated in metabolic and more general genetic differentiation and could be directly attributable to ploidy. Habitat differentiation increases the species' colonizing ability. It also amplifies divergence in reproductive strategy between diploids and tetraploids, which reduces ineffective crossing between cytotypes and thereby permits them to coexist in sympatry. The effect of hybridization at the polyploid level on the differentiation between cytotypes was assessed from the recent introduction of a foreign tetraploid entity into the study area. Hybridization between the two distinct tetraploids was found to increase habitat differentiation between the diploids and the tetraploids, but the major part of this differentiation is probably attributable to ploidy itself.     

Immunocytochemical localization of epidermal growth factor in mouse submandibular gland.

The cellular and subcellular localization of epidermal growth factor in the submandibular glands of male and female adult mice was established by immunoperoxidase techniques. In light microscopic preparations epidermal growth factor was found exclusively in the granular convoluted tubules of the gland. The intensity of staining for epidermal growth factor varied from cell to cell, and some cells apparently were negative. The pattern of staining was similar in the glands of male and female mice; however, the granular convoluted tubules are androgen-responsive, and thus more extensive and composed of larger cells in males. In thin sections epidermal growth factor was most heavily concentrated in the secretion granules of the granular convoluted tubule cells. Within a given cell there was variation in intensity of staining of individual secretion granules, with some granules appearing minimally reactive or negative. The only other cell component with deposits of reaction product was the ribosomes.     

Immunocytochemical localization of amylase in the parotid gland of developing and adult rats

An antiserum against purified rat parotid amylase was used to localize the protein in parotid glands of developing and adult rats. The unlabeled antibody peroxidase-antiperoxidase method and the protein A-gold colloid technique were used at the light and electron microscope levels, respectively. Immunoreactive amylase was detected in a few scattered cells in the glands of 2-day-old rats. During the following days the number of cells stained immunocytochemically for amylase increased rapidly; at 15 days of age all acinar cells revealed amylase, but the intensity of immunostaining varied from cell to cell. Electron microscopically, amylase was localized in the secretory granules, and by using a more concentrated antiserum, in the rough endoplasmic reticulum and Golgi complex. At early stages of development the acinar cells contained fewer and smaller secretory granules than in adult animals; the gold particles indicative of amylase were randomly distributed over the secretory granules. In the glands of adult rats, amylase was distributed inhomogeneously within the secretory granules. In the majority of secretory granules gold colloid particles were located over the electron-dense portions of the granules. However, secretory granules in which an amylase-rich shell surrounded an amylase-poor or amylase-negative "core" were not infrequent.     

Immunocytochemical localization of renin in the submandibular gland of the mouse during postnatal development.

The localization of renin in the developing mouse submandibular gland was studied immunocytochemically using the unlabelled antibody-enzyme method of Sternberger ('74). Bouin-fixed submandibular glands of mice of both sexes were examined at 5-day-intervals from birth (day 0) to 50 days of age. At all stages studied, only granular convoluted tubule (GCT) cells stained immunocytochemically for renin; such cells were first seen in glands of 30-day-old males and of 30-day-old females. The size and number of renin-containing GCT cells increased rapidly in males, attaining adult status by 50 days of age. In females, differentiation of GCT cells immunoreactive for renin was slower and less regular than in males, and at 50 days of age the GCT segment had not yet reached adult conditions with respect to the distribution of renin. Renin appears in GCT cells at later ages than other GCT cell products (e.g., EGF and amylase), suggesting the existence of independent developmental control for the expression of various biologically active substances in the GCTs.     

Synthesis of 2-Deoxy-4-thio-D-ribofuranose and Its 3-Azido Analogue from L-Arabinose; Intermediates in the Synthesis of 4′-Thiodeoxynucleosides

Abstract

1-O-Acetyl-3,5-di-O-benzoyl-2-deoxy-4-thio-α,β-D-ribofuranose and its 3-azido analogue have been prepared by an efficient route starting from L-arabinose. A key intermediate in this route is 2-deoxy-4,5-O-isopropylidene-L-erythro-pentose dibenzyl dithioacetal which is readily substituted in the 3-position thus offering extensive scope for the synthesis of 3-substituted 2-deoxy-4-thio-α,β-D-ribofuranoses and subsequent nucleoside derivatives.     

Characterisation of the yeast Pichia membranifaciens and its possible use in the biological control of Botrytis cinerea, causing the grey mould disease of grapevine

Pichia membranifaciens strain FY-101, isolated from grape skins, was found to be antagonistic to Botrytis cinerea, the causal organism of the grey mould disease of the grapevine. When grown together on solid as well as liquid media, the yeast brings about the inhibition of this parasitic fungus, coagulation and leakage of its cytoplasm, and suppression of its ability to produce the characteristic grey mould symptoms on the grapevine plantlets. In vitro experiments confirm that this yeast can be used as a biological control organism against B. cinerea. An account of the molecular characterisation of P. membranifaciens (complete sequence of the ITS region of its ribosomal DNA, GenBank accession No. AF 270935), as well as the interaction between B. cinerea and the yeast, are given here.     

Production of cell lines secreting TAT fusion proteins.

Transduction of proteins and other macromolecules constitutes a potent technology to analyze cell functions and to achieve therapeutic interventions. In general, fusion proteins with protein transduction domains, such as TAT, are produced in a bacterial expression system. Here we describe the generation of a mammalian expression vector coding for TAT-EGFP fusion protein. Transfection of CHO-K1 cells by this vector and subsequent selection by Zeocin resulted in cell lines that express and secrete EGFP, a variant of the green fluorescent protein GFP. The ultimate cell line was produced by first cloning the stable integrants and subsequent selection of EGFP-expressing cells by flow cytometric sorting. In the resulting cell line approximately 98% of cells express EGFP. Using the same methodology, we generated cell lines that express DsRed fluorescent protein. The advantages of using such a mammalian expression system include the ease of generating TAT fusion proteins and the potential for sustained production of such proteins in vitro and, potentially, in vivo.     

Ischémie myocardique du diabétique : apports de la scintigraphie myocardique de perfusion

Diabetes is an important risk factor of myocardial ischemia. Myocardial perfusion imaging (MPI) is used for diagnostic, prognostic assessment and for post-therapeutic follow-up of coronary artery disease (CAD). Its usefulness has been documented extensively in the general population. However, in diabetic population, little studies have been published. CAD is more severe and more frequent among diabetic patients. The goal of this work was to assess usefulness of MPI among diabetic patients. This work includes 44 diabetic patients (22 women, 22 men), investigated by stress MPI in nuclear medicine department of Ibn Rochd UH of Casablanca. The studied parameters concerned: age, antecedents of CAD, risk factors of CAD associated to diabetes, duration of the diabetes, diabetes complications, diabetes treatment, indication of MPI, presence or not of anomaly on the ECG performed at rest, existence or not of typical or atypical clinical signs of CAD, investigations and therapy prescribed as well as the occurrence or not of cardiac event during monitoring after MPI. Results of MPI have been compared to clinical, therapeutic and monitoring data of patients. Mean age of patients was 55 years (39 to 75 years), mean diabetes duration was 8.6 years (1 to 30 years), at least one diabetes complication has been noted in 18 patients. The most frequent complication was diabetic retinopathy. MPI has been achieved for diagnosis of ischemia in 37 patients and assessment of anti-ischemic treatment in 7 cases. Treadmill exercise has been achieved in 34 cases and a pharmacological stress in 10 others. During follow-up, which was between 1 and 36 months (mean: 14.9 months), 6 cardiac events occurred among the 44 patients. Patients with abnormal findings at stress MPI had two cardiovascular risk factors or more associated to diabetes (91.3% vs. 9.5% among patients having normal findings, P < 0.001) and had diabetic retinopathy more often (56.5% vs. 9.5% among patients with normal findings, P < 0.001). Cardiac events were more frequent among men (100% vs. 43.2% of patients who did not have a coronary event, P < 0.01). Patients with stress MPI showing ischemia in 3/17 segments or more have presented a cardiac event more often during the follow-up (4/12 Vs 2/32 among patients with normal MPI or defect in less than 3/17 segments, P < 0.01). In this series, coronary artery disease was found more frequently among patients having more than 2 cardiovascular risk factors. In addition, risk of cardiac event seems related to extent of uptake decrease.