Molecular beacons: nucleic acid hybridization and emerging applications

Molecular beacons (MBs) are a novel class of nucleic acid probes that become fluorescent when bound to a complementary sequence. Because of this characteristic, coupled with the sequence specificity of nucleic acid hybridization and the sensitivity of fluorescence techniques, MBs are very useful probes for a variety of applications requiring the detection of DNA or RNA. We survey various applications of MBs, including the monitoring of DNA triplex formation, and describe recent developments in MB design that enhance their sensitivity

Dependence of α-synuclein aggregate morphology on solution conditions

α-Synuclein is the major component of Lewy bodies and Lewy neurites, which are granular and filamentous protein inclusions that are the defining pathological features of several neurodegenerative conditions such as Parkinson's disease. Fibrillar aggregates formed from α-synuclein in vitro resemble brain-derived material, but the role of such aggregates in the etiology of Parkinson's disease and their relation to the toxic molecular species remain unclear. In this study, we investigated the effects of pH and salt concentration on the in vitro assembly of human wild-type α-synuclein, particularly with regard to aggregation rate and aggregate morphology. Aggregates formed at pH 7.0 and pH 6.0 in the absence of NaCl and MgCl, were fibrillar; the pH 6.0 fibrils displayed a helical twist, as clearly evident by scanning force and electron microscopy. Incubations at pH 7.0 remained transparent during the process of aggregation and exhibited strong thioflavin-T and weak 8-anilino-1-naphthalene-sulfonate (ANS) binding; furthermore, they were efficient in seeding fibrillization of fresh solutions. In contrast, incubating α-synuclein at low pH (pH 4.0 or pH 5.0) resulted in the rapid formation of turbid suspensions characterized by strong ANS binding, reduced thioflavin-T binding and reduced seeding efficiency. At pH 4.0, fibril formation was abrogated; instead, very large aggregates (dimensions similar to100 mum) of amorphous appearance were visible by light microscopy. As with acidic conditions, addition of 0.2 M NaCl or 10 mM MgCl, to pH 7.0 incubations led to a shorter aggregation lag time and formation of large, amorphous aggregates. These results demonstrate that the morphology of α-synuclein aggregates is highly sensitive to solution conditions, implying that the fibrillar state does not necessarily represent the predominant or most functionally significant aggregated state under physiological conditions. (C) 2002 Elsevier Science Ltd. All rights reserved

Distribution and abundance of cladocerans in the eastern Arabian Sea

Of the two species, Penilia avirostris Dana and Evadne tergestina Claus encountered, 86% of the population of the former occurred within the 50 m depth zone and 75% of the total population of the latter in the 50 m-100 m depth zone. Striking day-night variations in the population densities of Penilia and Evadne were observed. The samples collected at night contained 99.7% and 88% of the populations of the former and latter species respectively. Swarming of Evadne and Penilia is a regular phenomenon during the southwest monsoon season.The highest concentration of the former species was observed in August and that of the latter in September. High concentrations of Penilia and Evadne were observed in the 30 m depth zone off Cochin and in the 40 m depth zone off Karwar. The abundance of Penilia observed in the 30 m depth zone of Wadge Bank off Cape Comorin coincided with its maximum recorded in August off Cochin. The length frequency studies on Penilia and Evadne showed that different size classes dominated in the different regions from 07°N to 19°N and that an increase in size of the individuals was evident from south to north in both Penilia and Evadne. Fecundity of Penilia was the highest in the southernmost region between 07°00'N and 09°00'N while that of Evadne was in the northern region, 15°N- 19°N. Gamogenetic females of both Penilia and Evadne were very few in number. Occurrence of large numbers of parthenogenetic females of Penilia and Evadne with well developed advanced embroys in their brood pouches in the night samples probably suggest nocturnal brood maturation

Expanding the scope of ligand substitution from [M(S2C2Ph2] (M = Ni2+, Pd2+, Pt2+) to afford new heteroleptic dithiolene complexes

The scope of direct substitution of the dithiolene ligand from [M(S2C2Ph2)2] [M = Ni2+ (1), Pd2+ (2), Pt2+ (3)] to produce heteroleptic species [M(S2C2Ph2)2Ln] (n = 1, 2) has been broadened to include isonitriles and dithiooxamides in addition to phosphines and diimines. Collective observations regarding ligands that cleanly produce [M(S2C2Ph2)Ln], do not react at all, or lead to ill-defined decomposition identify soft σ donors as the ligand type capable of dithiolene substitution. Substitution of MeNC from [Ni(S2C2Ph2)(CNMe)2] by L provides access to a variety of heteroleptic dithiolene complexes not accessible from 1. Substitution of a dithiolene ligand from 1 involves net redox disproportionation of the ligands from radical monoanions, –S•SC2Ph2, to enedithiolate and dithione, the latter of which is an enhanced leaving group that is subject to further irreversible reactions

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An instance of abnormally ripe ovaries in the Indian Mackerel, Rastrelliger kanagurta (Cuvier)

A case of abnormally ripe ovaries, the first of its kind, is reported wherein an additional lobe in stage VI was found along with the normal pair of ovaries in stage IV. The estimated number of ripe and maturing ova in this abnormal sac was 18,600 each

AsaGEI2b: a new variant of a genomic island identified in the Aeromonas salmonicida subsp. salmonicida JF3224 strain isolated from a wild fish in Switzerland

Aeromonas salmonicida subsp. salmonicida is the causal agent of furunculosis in salmonids. We recently identified a group of genomic islands (AsaGEI) in this bacterium. AsaGEI2a, one of these genomic islands, has almost exclusively been identified in isolates from North America. To date, Aeromonas salmonicida subsp. salmonicida JF3224, a strain isolated from a wild brown trout (Salmo trutta) caught in Switzerland, was the only European isolate that appeared to bear AsaGEI2a. We analyzed the genome of JF3224 and showed that the genomic island in JF3224 is a new variant of AsaGEI, which we have called AsaGEI2b. While AsaGEI2b shares the same integrase gene and insertion site as AsaGEI2a, it is very different in terms of many other features. Additional genomic investigations combined with PCR genotyping revealed that JF3224 is sensitive to growth at 25°C, leading to insertion sequence-dependent rearrangement of the locus on the pAsa5 plasmid that encodes a type three secretion system, which is essential for the virulence of the bacterium. The analysis of the JF3224 genome confirmed that AsaGEIs are accurate indicators of the geographic origins of A. salmonicida subsp. salmonicida isolates and is another example of the susceptibility of the pAsa5 plasmid to DNA rearrangement

Salt Tolerance Mechanisms in Perennial Fodder Grasses

Salinity stress is one of the most damaging stresses in crop plants. It reduces the productivity of the soil and makes it unsuitable for crop cultivation. Fodder crops are considered the best alternative in such uncultivable land. Using salinity-affected land for pasture development is the best alternative to utilize such lands. However, the extent of salinity tolerance varies among different grass species. In this study, Pearl millet Napier hybrids (PMN hybrid) and guinea grass varieties were studied for salinity tolerance in artificially created saline soils in the ratio of 13:7:1:2 (NaCl: Na2SO4: MgCl: CaSO4, respectively) to understand the salinity tolerance mechanisms existing in perennial fodder grasses. Morphologically, the plant height increased in saline-tolerant PMN hybrid varieties, creating more space in nonphotosynthetic tissues to store accumulated salts away from photosynthetic tissues. Whereas in guinea grass tolerant varieties, tiller number increased under salinity. The fresh weight was highest under salinity in the PMN hybrids. In contrast, dry weight was high in control (no salt) plants, implying more water accumulation in PMN hybrids under salinity to dilute the concentration of salts absorbed by the plant. In Guinea grass, varieties like DGG1 had lower leaf succulence than control and high salt excretion through leaf hairs. Tissue tolerance in PMN hybrids was less compared to guinea grass. Membrane stability was maintained in saline-tolerant varieties. The double bond index increased in tolerant PMN hybrid varieties under salinity compared to control, implying fatty acid remodelling for maintaining the stability of membranes under salinity. Fodder grasses adopt various saline tolerance mechanisms based on their growth habit and morphology

Socioeconomic inequalities in health among Swedish adolescents - adding the subjective perspective

Abstract Background Socioeconomic inequalities in adolescent health predict future inequalities in adult health. Subjective measures of socioeconomic status (SES) may contribute with an increased understanding of these inequalities. The aim of this study was to investigate socioeconomic health inequalities using both a subjective and an objective measure of SES among Swedish adolescents. Method Cross-sectional HBSC-data from 2002 to 2014 was used with a total sample of 23,088 adolescents aged 11–15 years. Three measures of self-rated health (dependent variables) were assessed: multiple health complaints, life satisfaction and health perception. SES was measured objectively by the Family Affluence Scale (FAS) and subjectively by “perceived family wealth” (independent variables). The trend for health inequalities was investigated descriptively with independent t-tests and the relationship between independent and dependent variables was investigated with multiple logistic regression analysis. Gender, age and survey year was considered as possible confounders. Results Subjective SES was more strongly related to health outcomes than the objective measure (FAS). Also, the relation between FAS and health was weakened and even reversed (for multiple health complaints) when subjective SES was tested simultaneously in regression models (FAS OR: 1.03, CI: 1.00;1.06 and subjective SES OR: 0.66, CI: 0.63;0.68). Conclusions The level of socioeconomic inequalities in adolescent health varied depending on which measure that was used to define SES. When focusing on adolescents, the subjective appraisals of SES is important to consider because they seem to provide a stronger tool for identifying inequalities in health for this group. This finding is important for policy makers to consider given the persistence of health inequalities in Sweden and other high-income countries

Twisted large cellular fibroma of the ovary with pelvic effusion-revisiting incomplete demons Meigs’ syndrome

Fibromas of the ovary are benign tumours arising from the stromal component of the ovary. They represent 1% of ovarian neoplasms and are generally benign. The cellular subtype accounts for around 10% of these and is a tumour of uncertain malignant potential. Recurrence may occur or it could be associated with peritoneal implants. Usually these are solid tumours, sometimes with small areas of cystic degeneration. Occasionally, large fibromas may undergo torsion causing acute abdominal pain and generally tends to occur in post-menopausal women. The solid areas, ORADS and ascites simulated a malignant ovarian tumour on both MRI, USG and gross pathologic examination. Here we present a case of a postmenopausal woman presented with abdominal pain and postprandial vomiting with a large twisted ovarian fibroma leading to diagnostic and therapeutic challenges masquerading as a malignant ovarian neoplasm