We report here on a comparative developmental profile of plant hormone cytokinins in relation to cell size, cell number and endoreduplication in developing maize caryopsis of a cell wall ...invertase-deficient miniature1 (mn1) seed mutant and its wild type, Mn1, genotype. Both genotypes showed extremely high levels of total cytokinins during the very early stages of development, followed by a marked and genotype specific reduction. While the decrease of cytokinins in Mn1 was associated with their deactivation by 9-glucosylation, the absolute and the relative part of active cytokinin forms was higher in the mutant. During the exponential growth phase of endosperm between 6 d after pollination and 9 d after pollination, the mean cell doubling time, the absolute growth rate and the level of endoreduplication were similar in the two genotypes. However, the entire duration of growth was longer in Mn1 compared with mn1, resulting in a significantly higher cell number in the Mn1 endosperm. These data correlate with the previously reported peak levels of the Mn1-encoded cell wall invertase-2 (INCW2) at 12 d after pollination in the Mn1 endosperm. A model showing possible crosstalk among cytokinins, cell cycle and cell wall invertase as causal to increased cell number and sink strength of the Mn1 developing endosperm is discussed.
Autologous IgG were separated from rabbit sera and radiolabeled to perform scintigraphy. The IgG separation was accomplished with fast protein liquid chromatography. IgG were directly labeled with
...99mTc using stannous tartrate as reducing agent, sterilized with membrane filter and injected into rabbits. The method can be adopted for use in humans. It is suitable for repeated use as there is no danger of allergic reaction in the recipient.
We studied the adsorption of anaphylatoxins C3a and C5a on acrylonitrile (AN69) hollow-fiber (AN69HF) and plate (AN69P) dialyzers in 8 patients during 4-hour hemodialyses (HD). Blood passed first ...through a cuprophan dialyzer and then through AN69 dialyzers that were not in contact with dialysis fluid. Plasma C3a and C5a were measured in samples taken from the afferent and efferent blood lines of the acrylonitrile dialyzers at 15, 60 and 240 min. Plasma C3a concentrations decreased significantly in blood that had passed through AN69 dialyzers. This decrease, indicating membrane adsorption, was maximal (by 65% in AN69HF and by 59% in AN69P) at 15 min and minimal (by 53% in AN69HF and by 18% in AN69P) at 240 min. The decrease in plasma C5a concentrations was smaller and significant throughout HD only with AN69HF. The amount of C3a adsorbed was at least 45,000 micrograms in AN69HF and 18,000 micrograms in AN69P. These findings demonstrate that acrylonitrile dialyzers adsorb more C3a and C5a than they produce. This membrane adsorption may explain why the increase of plasma C3a and C5a is inhibited during HD.
To check whether in vivo EDTA prevents complement activation resulting from blood contact with the dialyzer membrane, sham hemodialysis (HD) was performed in seven healthy volunteers using Cuprophan ...hollow-fiber dialyzers. Blood samples were drawn from the arterial and venous blood lines of the dialyzer before and after EDTA was infused into the arterial line. Venous line plasma C3a concentrations before EDTA infusion were significantly higher than after EDTA. Also, venous line plasma C3a concentrations before and after EDTA infusion were significantly higher than in the arterial line. These results indicate that complement activation can be attenuated by EDTA during sham HD. Technical improvements in the procedure may permit complete inhibition of complement activation.
Abstract
Background
Despite enormous efforts, early diagnosis of Alzheimer’s disease (AD) remains difficult. To date, there is no reliable diagnostic tool to identify biomarkers in the developing ...stages of AD 1. In recent years, our group has focused part of the research on the development of small fluorescent molecules capable of effectively labelling AD biomarkers such as amyloid β plaques and tau protein 2, 3.
Methods
We designed and synthesised a library of small fluorescent molecules that were tested
in vitro
for their binding affinity (
K
d
) and change in optical properties upon binding to amyloid β fibrils. In addition, the most promising molecules were used to perform
ex vivo
labelling of
post‐mortem
AD brain tissue examined by fluorescence microscopy.
Results
Our synthesized fluorescent probes consist of three building blocks, i.e., electron‐donating (EDG) and electron‐withdrawing groups (EWG), linked to different unsaturated hydrocarbon (HC) linkers (Figure 1), which enable the so‐called “push‐pull” effect leading to fluorescence. First, we investigated how the individual building blocks affect the spectroscopic properties (absorption, emission, excitation, quantum yield) of the prepared molecules in different solvents, representing a simplified polarity model of the AD biomarker binding sites (Figure 2). Furthermore, the compounds evaluated
in vitro
bound to amyloid β
1‐42
fibrils with submicromolar
K
d
values. Moreover, the selected compounds were shown to successfully stain amyloid β plaques as well as tau proteins on AD brain slices (Figure 2).
Conclusion
Based on the results we conducted structure‐spectroscopic‐affinity relationship study and determined how the building blocks of our fluorescent probes affect the optical as well as affinity properties when bound to amyloid β fibrils. Through
in vitro
and
ex vivo
studies, our probes are being systematically tested to identify the best candidate capable of achieving our final goal – the early detection of AD biomarkers in the patient’s blood, which would lead to a generally applicable, minimally invasive, cost‐effective, and long‐term traceable diagnostic assay.
1. Hansson, O., et al., Alzheimers. Dement.,
2022
,
18
, 2669‐2686.
2. Šarlah, D., et al., Molecules,
2016
,
21
, 267.
3. Rejc, L., et al., J. Med. Chem.,
2017
,
60
,8741‐8757.
Microplastics (MP), small plastic particles below 5 mm, have become one of the central concerns of environmental risk assessment. Microplastics are continuously being released into the aquatic ...environment either directly through consumer products or indirectly through fragmentation of larger plastic materials. The aim of our study was to investigate the effect of polyethylene microbeads from cosmetic products on duckweed (Lemna minor), a freshwater floating plant. The effects of microbeads from two exfoliating products on the specific leaf growth rate, the chlorophyll a and b content in the leaves, root number, root length and root cell viability were assessed. At the same time, water leachates from microbeads were also prepared to exclude the contribution of cosmetic ingredients on the measured impacts. Specific leaf growth rate and content of photosynthetic pigments in duckweed leaves were not affected by polyethylene microbeads, but these microbeads significantly affected the root growth by mechanical blocking. Sharp particles also reduced the viability of root cells, while the impact of microbeads with a smooth surface was neglected. It was concluded that microbeads from cosmetic products can also have negative impacts on floating plants in freshwater ecosystems.
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•Impact of polyethylene microbeads on duckweed was investigated.•Microbeads do not affect leaf growth rate and photosynthetic pigment content.•They significantly affect root length and root cell viability of duckweed.
Polyethylene microbeads significantly affects root length and root cell viability.
The phytohormone auxin (indole-3-acetic acid IAA) plays a fundamental role in vegetative and reproductive plant development. Here, we characterized a seed-specific viable maize (Zea mays) mutant, ...defective endosperm18 (de18) that is impaired in IAA biosynthesis, de18 endosperm showed large reductions of free IAA levels and is known to have approximately 40% less dry mass, compared with De18. Cellular analyses showed lower total cell number, smaller cell volume, and reduced level of endoreduplication in the mutant endosperm. Gene expression analyses of seed-specific tryptophan-dependent IAA pathway genes, maize Yucca1 (ZmYuc1), and two tryptophan-aminotransferase co-orthologs were performed to understand the molecular basis of the IAA deficiency in the mutant. Temporally, all three genes showed high expression coincident with high IAA levels; however, only ZmYuc1 correlated with the reduced IAA levels in the mutant throughout endosperm development. Furthermore, sequence analyses of ZmYuc1 complementary DNA and genomic clones revealed many changes specific to the mutant, including a 2-bp insertion that generated a premature stop codon and a truncated YUC1 protein of 212 amino acids, compared with the 400 amino acids in the De18. The putative, approximately 1.5-kb, Yuc1 promoter region also showed many rearrangements, including a 151-bp deletion in the mutant. Our concurrent high-density mapping and annotation studies of chromosome 10, contig 395, showed that the De18 locus was tightly linked to the gene ZmYuc1. Collectively, the data suggest that the molecular changes in the ZmYuc1 gene encoding the YUC1 protein are the causal basis of impairment in a critical step in IAA biosynthesis, essential for normal endosperm development in maize.
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