Anatomical and chemical characteristics of the seed coat of <i>Medicago sativa</i> L. (alfalfa) cv. Baralfa 85 seeds and their association with seed dormancy

Seeds of alfalfa (Medicago sativa L.) can exhibit seedcoat imposed dormancy, which produces hard seeds within a seed lot. These seeds do not germinate because they do not imbibe water due to a barrier to water entry in the seed coat. The aim of this work was to analyze the anatomical and chemical characteristics of the testa of alfalfa seeds with respect to water permeability levels. The anatomy of seeds of the cv. Baralfa 85 was studied and structural substances, polyphenols, tannins and cutin present in the testa of seeds of different water permeability levels were determined. The anatomical characteristics of the seed coat and the proportions of components were found to determine the permeability level of the seed coat, an aspect that is associated with the physical seed dormancy level. Anatomically, increased thickness of the testa was associated with a lower permeability level. The difference may be attributed to the variation in cuticle thickness, length of macrosclereids and thickness of the cell wall, and presence and development of osteosclereids. From the physiological and chemical points of view, the mechanism of physical dormancy of the testa is explained by a greater amount of components that repel water and cement the cell wall, such as polyphenols, lignins, condensed tannins, pectic substances, and a lower proportion of cellulose and hemicellulose.     

Alternative splicing and protein function

Background  

Alternative splicing is a major mechanism of generating protein diversity in higher eukaryotes. Although at least half, and probably more, of mammalian genes are alternatively spliced, it was not clear, whether the frequency of alternative splicing is the same in different functional categories. The problem is obscured by uneven coverage of genes by ESTs and a large number of artifacts in the EST data.     

Feedback equilibrium control during human standing

Equilibrium maintenance during standing in humans was investigated with a 3-joint (ankle, knee and hip) sagittal model of body movement. The experimental paradigm consisted of sudden perturbations of humans in quiet stance by backward displacements of the support platform. Data analysis was performed using eigenvectors of motion equation. The results supported three conclusions. First, independent feedback control of movements along eigenvectors (eigenmovements) can adequately describe human postural responses to stance perturbations. This conclusion is consistent with previous observations (Alexandrov et al., 2001b) that these same eigenmovements are also independently controlled in a feed-forward manner during voluntary upper-trunk bending. Second, independent feedback control of each eigenmovement is sufficient to provide its stability. Third, the feedback loop in each eigenmovement can be modeled as a linear visco-elastic spring with delay. Visco-elastic parameters and time-delay values result from the combined contribution of passive visco-elastic mechanisms and sensory systems of different modalities     

Immunomodulation activity of new vaccines for pertussis prophylaxis--acellular pertussis vaccine and adsorbed DPT vaccine with acellular component

The immunomodulating activity of acellular pertussis vaccine (APV) and adsorbed DPT vaccine with acellular pertussis component (DPTA vaccine) was studied. The study revealed that only large doses of APV, 10 immunizing doses (ID), suppressed humoral and cell-mediated response to sheep red blood cells (SRBC). 1 ID produced no influence on the formation of antibody producing cells, but increased the development of delayed hypersensitivity (DH) to SRBC. The modulation of cell-mediated immune response, induced by APV, returned to normal after the injection of purified staphylococcal toxoid, used as immunomodulator, in doses of 0.15 BU per mouse and 1.5 BU per mouse. DPTA vaccine containing 1 ID, as well as 10 ID, produced no immunomodulating effect. This was established by the evaluation of humoral response to SRBC in CBA mice and the study of the formation of DH to SRBC in BALB/c mice. As indicated by the total of the presented data, the inclusion of APV into DPTA vaccine enhanced the immunological safety of its pertussis component.     

The PINE study: rationale and design of a randomised comparison of epidural injection of local anaesthetics and steroids versus care-as-usual to prevent postherpetic neuralgia in the elderly [ISRCTN32866390]

BACKGROUND: Postherpetic neuralgia (PHN) is by far the most common complication of herpes zoster (HZ) and one of the most intractable pain disorders. Since PHN is seen most often in the elderly, the number of patients with this disorder is expected to increase in our ageing society. PHN may last for months to years and has a high impact on the quality of life. The results of PHN treatment are rather disappointing. Epidural injection of local anaesthetics and steroids in the acute phase of HZ is a promising therapy for the prevention of PHN. Since randomised trials on the effectiveness of this intervention are lacking, the PINE (Prevention by epidural Injection of postherpetic Neuralgia in the Elderly) study was set up. The PINE study compares the effectiveness and cost-effectiveness of a single epidural injection of local anaesthetics and steroids during the acute phase of HZ with that of care-as-usual (i.e. antivirals and analgesics) in preventing PHN in elderly patients. METHODS / DESIGN: The PINE study is an open, multicenter clinical trial in which 550 elderly (age >/= 50 yr.) patients who consult their general practitioner in the acute phase of HZ (rash < 7 days) are randomised to one of the treatment groups. The primary clinical endpoint is the presence of HZ-related pain one month after the onset of the rash. Secondary endpoints include duration and severity of pain, re-interventions aiming to treat the existing pain, side effects, quality of life, and cost-effectiveness. CONCLUSION: The PINE study is aimed to quantify the (cost-) effectiveness of a single epidural injection during the acute phase of HZ on the prevention of PHN.     

Humoral response to the injection of acellular Pertussis vaccine

The humoral response of mice and rabbits to the injection of whole-cell pertussis vaccine (PV) and acellular pertussis vaccine (APV), developed at the Mechnikov Research Institute for Vaccines and Sera (Russian Acad. Med. Sci.) in Moscow, was studied. In the sera of immunized animals antibodies to the antigenic complex were determined in the direct hemagglutination (DHA) test, specific antibodies to filamentous hemagglutinin (FHA) and pertussis toxin (PT)--in the enzyme immunoassay (EIA) and antibodies neutralizing PT in a cytopathogenic dose (CPD)--in neutralization test on Chinese hamster ovary (CHO) cells. In mice and rabbits immunized with APV the antibody titers determined in the DHA test were higher than those in the animals immunized with PV. Specific antibodies titers to FHA and PT in the sera of rabbits immunized with APV were also higher than those in the sera of rabbits immunized with PV. High dilutions of sera taken from the animals immunized with APC neutralized 4-16 doses of PT in the neutralization test on CHO cells. The most important result of this study was the detection of a more pronounced immune response in the animals immunized with APV in comparison with that induced by PV according to the results obtained in EIA and in the test of PT CPD neutralization on CHO cells.     

Can the presence of curved forms of the diatom Aulacoseira ambigua in the Nile (Egypt) and Vaal (South Africa) Rivers be ascribed to similar water quality conditions?

Spiral colonies of the diatom Aulacoseira ambigua were assigned the rank of forma (Aulacoseira ambigua f. japonica). This spiral-shaped, colonial, centric diatom has limited geographical distribution and is currently reported to occur in only a few countries in the world. In Africa this species was described for the first time from the Vaal River, South Africa, but recent research on the Nile River also revealed its presence in Egypt. Physical and chemical data on water quality in these two river systems were compared to determine whether the presence of this uncommon ‘phenoecodeme’ could be ascribed to similar environmental conditions. Results indicate that the rivers are dissimilar with regard to many variables, but both rivers provide turbid, warm and eutrophic waters with medium to high mineral content and it was concluded that these factors favour and sustain the growth of this curved form.     

Laboratory evaluation of certain natural compounds against the melon ladybird beetle,Epilachna chrysomelina F. attacking cucurbit plants

Neem Azal-T/S, Neudosan and Spruzit flüssig at different concentrations were evaluated against the second and fourth instar larvae of E. chrysomelina under laboratory conditions. In case of acute effects, the highest mortality was recorded when larvae were offered squash leaves treated with the highest concentration (2%) of Neem Azal-T/S, and the lowest mortality was, however recorded after treating them with the lowest concentration (0.25%). On the other hand, the second instar larvae were more susceptible to any compound at any concentration than the fourth instar one. One per cent Neudosan formulation showed the highest toxicity to both the 2nd and 4th instar larvae. As the concentration of this compound decreased the mortality percentage of treated larvae decreased to reach the minimum at the lowest concentration (0.25%). The same trend could be applied for Spruzit flüssig compound. When Neem Azal-T/S was compared with Neudosan, the later at any concentration was more toxic than the former. Generally, Neudosan and Spruzit flüssig seemed to be active against E. chrysomelina during the first three days after treatment, then, deterioration occurred among this compound. In case of latent effects, the duration of the treated fourth instar larvae of E. chrysomelina with any tested compound, was prolonged. An increase in the concentration caused prolongation of this period to reach the longest at the highest concentration. This prolongation, was more pronounced after Neem Azal-T/S treatment followed by Neudosan and Spruzit flüssig. The same trend could be applied for the duration of the pupal stage as being affected by the different concentrations of the tested compounds which were applied to the fourth instar larvae. However, adults of E. Chrysomelina treated as fourth instar larvae with high concentrations of Neem Azal-T/S showed some adult malformations. The sex ratios of adults produced from fourth instar larvae treated with different concentrations of the tested natural compounds were about 1?:?1, except for two cases; 1% Neudosan where the number of females were double the number of males and 0.5% Spruzit flüssig where the number of males were double the number of females. An increase in the concentration of any tested compound caused an obvious decrease in the percentage of emerged adults. The least emergence percentage was recorded in the case of Spruzit flüssig, followed by Neudosan and Neem Azal-T/S. Treating the fourth instar larvae with the different concentrations of the tested natural compounds significantly shortened the longevity of produced adults and decreased the fecundity.     

Impact of folic acid fortification on global DNA methylation and one-carbon biomarkers in the Women's Health Initiative Observational Study cohort

DNA methylation is an epigenetic mechanism that regulates gene expression and can be modified by one-carbon nutrients. The objective of this study was to investigate the impact of folic acid (FA) fortification of the US food supply on leukocyte global DNA methylation and the relationship between DNA methylation, red blood cell (RBC) folate, and other one-carbon biomarkers among postmenopausal women enrolled in the Women's Health Initiative Observational Study. We selected 408 women from the highest and lowest tertiles of RBC folate distribution matching on age and timing of the baseline blood draw, which spanned the pre- (1994–1995), peri- (1996–1997), or post-fortification (1998) periods. Global DNA methylation was assessed by liquid chromatography-tandem mass spectrometry and expressed as a percentage of total cytosine. We observed an interaction (P = 0.02) between fortification period and RBC folate in relation to DNA methylation. Women with higher (vs. lower) RBC folate had higher mean DNA methylation (5.12 vs. 4.99%; P = 0.05) in the pre-fortification period, but lower (4.95 vs. 5.16%; P = 0.03) DNA methylation in the post-fortification period. We also observed significant correlations between one-carbon biomarkers and DNA methylation in the pre-fortification period, but not in the peri- or post-fortification period. The correlation between plasma homocysteine and DNA methylation was reversed from an inverse relationship during the pre-fortification period to a positive relationship during the post-fortification period. Our data suggest that (1) during FA fortification, higher RBC folate status is associated with a reduction in leukocyte global DNA methylation among postmenopausal women and; (2) the relationship between one-carbon biomarkers and global DNA methylation is dependent on folate availability.