Easy determination of ploidy level in Arabidopsis thaliana plants by means of pollen size measurement

Summary Cytogenetic examination of transgenic Arabidopsis thaliana (L.) Heynh. plants obtained by Agrobacterium-mediated gene transfer to cotyledon- and root-explants or by direct gene transfer into protoplasts revealed a high percentage of tetraploid or aneuploid transformants. Depending on the transformation procedure used, 13% (root explant transformation), 33% (cotyledon explant transformation), or 38% (direct gene transfer) of the transformants showed aberrant ploidy levels. A good correlation between the ploidy level of a plant and the size of its pollen grains was observed. This allows quick and simple testing of the ploidy level of transgenic Arabidopsis plants.Abbreviations AM Arabidopsis medium - ANOVA analysis of variance - DAPI 4,6-Diamidino-2-phenylindole - PEG polyethyleneglycol     

The carbohydrate chains of the beta subunit of human chorionic gonadotropin produced by the choriocarcinoma cell line BeWo. Novel O-linked and novel bisecting-GlcNAc-containing N-linked carbohydrates.

The N-linked carbohydrate chains of the beta subunit of human chorionic gonadotropin (hCG-beta) isolated from the culture fluid of the choriocarcinoma cell line BeWo were released enzymatically by peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F. Subsequently, the O-linked oligosaccharides were split off from the N-deglycosylated protein by mild alkaline borohydride treatment. The carbohydrate chains were purified in their intact sialylated forms by FPLC anion-exchange chromatography on Mono Q, HPLC on Lichrosorb-NH2, and high-pH anion-exchange chromatography on CarboPac PA1. 1H-NMR spectroscopic analysis of the major fractions demonstrates the occurrence of the following sialylated diantennary and triantennary N-linked oligosaccharides. Residues not written in bold letters are variably present. [formula: see text] The incidence of triantennary carbohydrate chains is much higher than in normal urinary hCG-beta (26% vs 2%). The same holds for the alpha 1-6-fucosylation of the asparagine-bound GlcNAc (95% vs 42%). The presence of a bisecting GlcNAc and the occurrence of alpha 2-6-linked Neu5Ac in the most abundant N-glycans, are new features for hCG-beta. The major O-linked carbohydrate chains identified are the tetrasaccharide Neu5Ac alpha 2-3Gal beta 1-3(Neu5Ac alpha 2-6)GalNAc-ol and the hexasaccharide Neu5Ac alpha 2-3Gal beta 1-4GlcNAc beta 1-6(Neu5Ac alpha 2-3Gal beta 1-3)GalNAc-ol, both also found in normal urinary hCG. In addition, two novel O-glycans were characterized: [formula: see text]     

Structure determination of the major N- and O-linked carbohydrate chains of the beta subunit from equine chorionic gonadotropin

The carbohydrate moieties of equine chorionic gonadotropin alpha and beta subunits were released from the protein backbones by successive treatments with peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F and alkaline borohydride and then fractionated by FPLC and HPLC. The major N- and O-linked glycans of the beta subunit were characterized by 500-MHz 1H-NMR spectroscopy, showing a remarkable structural heterogeneity for the N-glycosidically linked chains, comprising mono-, di-, tri- and tri'-antennary N-acetyllactosamine type of glycans, being partly alpha 1-6 fucosylated at the Asn-bound GlcNAc residue and having alpha 2-6 and alpha 2-3 linked N-acetyl- and N-acetyl-4-O-acetylneuraminic acid residues as sialic acid constituents. Significant differences in this respect were detected for the partially characterized glycans of the alpha subunit. The major part of the O-linked carbohydrate chains, occurring solely in the beta subunit, is formed by tri-, tetra-, penta- and hexa-saccharides. There are indications for the presence of oligo(N-acetyllactosamine) units in both the N- and O-linked glycans of the beta subunit.     

The Effect of Ag Nanoparticles on Surface-Enhanced Luminescence from Au Nanovoid Arrays

Studies comparing the effect of adding two different nanoparticle compositions on the plasmonic properties of Au nanovoid arrays were undertaken. Surface-enhanced resonance luminescence and surface-enhanced resonance Raman studies comparing dispersed Ag nanoparticles and Ag nanoparticle aggregates on gold nanovoid arrays were undertaken. These studies showed that using Ag nanoparticle aggregates increased both luminescence and Raman efficiency relative to when dispersed nanoparticles were used; in addition, these studies also showed that adding dispersed Ag nanoparticles supported a more reproducible enhancement in luminescence and Raman across the substrate compared to using Ag nanoparticle aggregates. Finite element analysis simulations indicated that surface plasmon polariton distribution in the sample was affected by the presence of the Ag nanoparticles on the Au nanovoid array.     

Geochemistry and Microbial Populations in Sediments of the Northern Baffin Bay,Arctic

The Northern Baffin Bay between Greenland and Canada is a remote Arctic area restricted in primary production by seasonal ice cover, with presumably low sedimentation rates, carbon content and microbial activities in its sediments. Our aim was to study the so far unknown subseafloor geochemistry and microbial populations driving seafloor ecosystems. Shelf sediments had the highest organic carbon content, numbers of Bacteria and Archaea, and microcosms inoculated from Shelf sediments showed highest sulfate reduction and methane production rates. Sediments in the central deep area and on the southern slope contained less organic carbon and overall lower microbial numbers. Similar 16S rRNA gene copy numbers of Archaea and Bacteria were found for the majority of the sites investigated. Sulfate in pore water correlated with dsrA copy numbers of sulfate-reducing prokaryotes and differed between sites. No methane was found as free gas in the sediments, and mcrA copy numbers of methanogenic Archaea were low. Methanogenic and sulfate-reducing cultures were enriched on a variety of substrates including hydrocarbons. In summary, the Greenlandic shelf sediments contain vital microbial communities adapted to their specific environmental conditions.     

Risk Factors for Hyperglycaemia in Pregnancy in Tamil Nadu,India

Introduction

Hyperglycaemia in pregnancy (HIP), i.e. gestational diabetes mellitus (GDM) and diabetes in pregnancy (DIP), increases the risk of various short- and long-term adverse outcomes. However, much remains to be understood about the role of different risk factors in development of HIP.

Objective

The aims of this observational study were to examine the role of potential risk factors for HIP, and to investigate whether any single or accumulated risk factor(s) could be used to predict HIP among women attending GDM screening at three centres in urban, semi-urban and rural Tamil Nadu, India.

Methodology

Pregnant women underwent a 75 g oral glucose tolerance test. Data on potential risk factors was collected and analysed using logistical regression analysis. Receiver operating characteristic (ROC) curves, sensitivity, specificity and predictive values were calculated for significant risk factors and a risk factor scoring variable was constructed.

Results

HIP was prevalent in 18.9% of the study population (16.3% GDM; 2.6% DIP). Increasing age and BMI as well as having a mother only or both parents with diabetes were significant independent risk factors for HIP. Among women attending the rural health centre a doubling of income corresponded to an 80% increased risk of HIP (OR 1.80, 95%CI 1.10–2.93; p = 0.019), whereas it was not significantly associated with HIP among women attending the other health centres. The performance of the individual risk factors and the constructed scoring variable differed substantially between the three health centres, but none of them were good enough to discriminate between those with and without HIP.

Conclusions

The findings highlight the importance of socio-economic circumstances and intergenerational risk transmission in the occurrence of HIP as well as the need for universal screening.     

Explicit-solvent molecular dynamics simulations of the polysaccharide schizophyllan in water

Schizophyllan is a beta(1-->3)-D-glucan polysaccharide with beta(1-->6)-branched lateral glucose residues that presents a very stiff triple-helical structure under most experimental conditions. Despite the remarkable stability of this structure (which persists up to 120 degrees C in aqueous solution), schizophyllan undergoes a major change of state around 7 degrees C in water that has been hypothesized to result from an order-disorder transition in the lateral residues. This hypothesis is only supported by indirect experimental evidence and detailed knowledge (at the atomic level) concerning hydrogen-bonding networks, interactions with the solvent molecules, orientational freedom of the lateral residues, and orientational correlations among them is still lacking. In this study explicit-solvent molecular dynamics simulations of a schizophyllan fragment (complemented by simulations of its tetrasaccharide monomer) are performed at three different temperatures (273 K, 350 K, and 450 K) and with two different types of boundary conditions (finite nonperiodic or infinite periodic fragment) as an attempt to provide detailed structural and dynamical information about the triple-helical conformation in solution and the mechanism of the low-temperature transition. These simulations suggest that three important driving forces for the high stability of the triple helix are i), the limited conformational work involved in its formation; ii), the formation of a dense hydrogen-bonding network at its center; and iii), the formation of interchain hydrogen bonds between main-chain and lateral glucose residues. However, these simulations evidence a moderate and continuous variation of the simulated observables upon increasing the temperature, rather than a sharp transition between the two lowest temperatures (that could be associated with the state transition). Although water-mediated hydrogen-bonded association of neighboring lateral residues is observed, this interaction is not strong enough to promote the formation of an ordered state (correlated motions of the lateral residues), even at the lowest temperature considered.     

Low-temperature micronization of a peptide drug in fluid propellant: Case study cetrorelix

Aim of this study was to elaborate an efficient method for the micronization of the decapeptide cetrorelix (a GnRH-antagonist), in order to obtain a microsuspension as basis for other pharmaceutical preparations, such as e.g. inhalation aerosols. A modified pearl-mill coupled with a cryostat was used for the micronization of cetrorelix in fluid propellant and operated under different conditions. The obtained cetrorelix suspensions were analyzed for particle size distribution, purity of cetrorelix, and for metal contamination through abrasion from parts of the mill. The method allowed an effective micronization of cetrorelix. The mean particle size of the initial cetrorelix lyophilizate bulk ware was reduced from 52.5 μ (Volume Mean Diameter, VMD) down to 14.9, 6.1 and 3.1 μm, respectively, respectively. The HPLC analysis of all cetrorelix suspensions after micronization did not show signs of decomposition as compared to the initial product. The elementary analysis of the suspensions performed by inductively coupled plasma mass spectrometry revealed a negligible amount of contaminants in the suspension (Zr=max. 0.6 ppm; Fe, Cr, Ni, Ba, below limit of quantification, i.e.<0.14 ppm). The only appreciable contaminant. Aluminum (Al=1.1 ppm), was derived from the mechanical capping of aluminum canisters prior to analysis. The Zr determination in the suspension of 0.6 ppm, is still considered to be negligible as compared to the legally tolerated limit of air contamination. By low-temperature micronization in fluid propellant, fine drug suspensions of cetrorelix for pMDIs can be directly manufactured in one-step procedure without destruction of the peptide structure and without appreciable product contamination. Published: July 12, 2001.     

Intranasal volume and olfactory function

The aim of this exploratory study was to identify the volume intranasal segments as they relate to parameters of olfactory function. Fifty healthy male volunteers (age range 22-59 years, mean age 28.5 years) were included. Olfactory function was measured by lateralized phenyl ethyl alcohol odor thresholds and odor discrimination, and by bilateral odor identification. Magnetic resonance imaging of the nasal cavity was performed immediately following olfactometry. To correlate the results of olfactometry with intranasal volume, each nasal cavity was divided into 11 segments. Significant correlations were found between the odor thresholds and volumes of the anterior part of the lower and upper meatus of the right nasal cavity. These results reveal that two nasal segments are important for inter-individual differences of odor thresholds in healthy subjects: (i) the segment in the upper meatus below the cribriform plate and (ii) the anterior segment of the inferior meatus. The latter finding is of special interest for nasal surgery, which allows modification of this volume through resection of the inferior turbinate and/or septoplasty.