Seed physical dormancy of cassytha filiformis (laurceae, magnolideae); A hemiparasitic angiosperm

Cassytha filiformis is a hemi parasitic member of the family Lauraceae with a panatropical distribution. In Sri Lanka it is distributed in both wet and dry zones, associated with seashore and mangrove vegetations. Although, in many countries C. filiformis has been recorded as a parasitic weed, it is utilized in folk medicine in several countries. However, no information is available on the seed dormancy, germination and seed storage behaviour of this genus. Thus, the primary aim of this study was to gather information on the dormancy, germination and storage behaviour of C.filiformis fruits (dispersal unit).Mature fruits were collected from numerous vines in Ambalangoda. Fruit moisture content (FMC) was determined using oven dry method. Imbibition and germination of untreated and manually scarified fruits was studied. Dye (Methelene blue) tracking experiments were carried out to confirm the physical dormancy (PY). Hand sections of fruits were observed under a light microscope to study the anatomy of fruit and seed coat. Several treatments (dry heat, boiling water, acid scarification and sand paper scarification) were used to break the PY of fruits of C.filiformis.FMC of C. filiformis (10.5±0.9 %) reveals that fruits are orthodox in storage behaviour. Manually scarified fruits increased mass >80% while, untreated fruits increased mass <16%. Manually scarified fruits germinated significantly higher percentage (80%) than untreated fruits (25%). Methelene blue did not penetrate through the endocarp. Thus, it could be concluded that C. filiformis fruits have PY. Light microscopy of seed sections confirmed the presence of a palisade layer in the endocarp where as palisade layer have been identified as water impermeable layers in seeds with PY. However, none of the treatments except sandpaper scarification were successful in breaking PY. This is the first record of PY in Magnolidae (Lauraceae) and with this record; number of families producing seeds/fruits with PY has been increased to 18

Physiological Epicotyl Dormancy and Recalcitrant Storage Behaviour in Seeds of Two Tropical Fabaceae (Subfamily Caesalpinioideae) Species

BACKGROUND AND AIMS: Physiological epicotyl dormancy in which the epicotyl elongates inside the seed before the shoot emerges has been reported for only a few tropical rainforest species, all of which are trees that produce recalcitrant seeds. In studies on seeds of Fabaceae in Sri Lanka, we observed a considerable time delay in shoot emergence following root emergence in seeds of the introduced caesalpinioid legumes Brownea coccinea and Cynometra cauliflora. Thus, our aim was to determine if seeds of these two tropical rainforest trees have physiological epicotyl dormancy, and also if they are recalcitrant, i.e. desiccation sensitive. METHODOLOGY: Fresh seeds were (i) dried to various moisture levels, and (ii) stored at -1 and 5 °C to determine loss (or not) of viability and thus type of seed storage behaviour (orthodox, recalcitrant or intermediate). To identify the kind of dormancy, we tested the effect of scarification on imbibition and monitored radicle emergence and epicotyl growth (inside the seed) and emergence. PRINCIPAL RESULTS: FRESH SEEDS OF BOTH SPECIES HAD HIGH MOISTURE CONTENT (MC): 50 % for C. cauliflora and 30 % for B. coccinea. Further, all seeds of C. cauliflora and the majority of those of B. coccinea lost viability when dried to 15 % MC; most seeds of both species also lost viability during storage at -1 or 5 °C. Intact seeds of both species were water permeable, and radicles emerged in a high percentage of them inHowever, shoot emergence lagged behind root emergence by 77 ± 14 days in B. coccinea and by 38 ± 4 days in C. cauliflora. Further, plumule growth inside seeds of C. cauliflora began almost immediately after radicle emergence but not until ∼30-35 days in B. coccinea seeds. CONCLUSIONS: Seeds of both species are recalcitrant and have physiological epicotyl dormancy. The kind of physiological epicotyl dormancy in seeds of C. cauliflora has not been described previously; the formula is C(nd) (root)-[Formula: see text] (epicotyl)

Methylene tetrahydrofolate reductase, transforming growth factor-β1 and lymphotoxin-α genes polymorphisms and susceptibility to rheumatoid arthritis

AbstractBackgroundRheumatoid arthritis is a widely prevalent autoimmune disorder with suggested genetic predisposition.ObjectivesThe aim of this study is to detect the pattern of genetic polymorphism of methylene tetrahydrofolate reductase (MTHFR C677 T and A1298 C), transforming growth factor-β1 (TGF-β1 T869 C) and lymphotoxin-α (LT-α A252G) in patients having rheumatoid arthritis and correlate these patterns to disease activity and serum levels of tumor necrosis factor-alpha (TNF-α), B-Cell Activating Factor (BAFF), and osteopontin.MethodsA total of 194 subjects, 90 controls and 104 patients with rheumatoid arthritis were genotyped for MTHFR C677 T and A1298 C, TGF-β1 T869 C and LT-α A252G polymorphisms using a methodology based on PCR-RFLP. Also serum levels of TNF-α, osteopontin and BAFF were measured by ELISA kits.ResultsThe CT genotype and T allele of MTHFR C677 T and GG genotype and G allele of LT-α A252G are associated with the risk of RA and with higher levels of the pro-inflammatory cytokine, TNF-α in patients with rheumatoid arthritis.ConclusionOur findings suggest that there is association between MTHFR C677 T and LT-α A252G genes polymorphisms and increased risk of RA in this sample of Egyptian population

Polimorfismos dos genes metilenotetrahidrofolato redutase, fator de crescimento transformador β1 e linfotoxina‐α e susceptibilidade à artrite reumatoide

ResumoAntecedentesA artrite reumatoide é uma doença autoimune amplamente prevalente com sugerida predisposição genética.ObjetivosDetectar o padrão de polimorfismo dos genes metilenotetrahidrofolato redutase (MTHFR C677T e A1298C), fator de crescimento transformador β1 (TGF‐β1 T869C) e linfotoxina‐α (LT‐α A252G) em pacientes com artrite reumatoide e correlacionar esses padrões com a atividade da doença e os níveis séricos de fator de necrose tumoral alfa (TNF‐α), fator ativador de linfócitos B (BAFF) e osteopontina.MétodosForam genotipados 194 indivíduos – 90 controles e 104 com artrite reumatoide – à procura de polimorfismos dos genes MTHFR C677T e A1298C, TGF‐β1 T869C e LT‐α A252G com uma metodologia baseada na PCR‐RFLP. Mensuraram‐se também os níveis séricos de TNF‐α, osteopontina e BAFF com kits de Elisa.ResultadosO genótipo CT e o alelo T do MTHFR C677T e o genótipo GG e alelo G do LT‐α A252G estão associados ao risco de AR e a níveis mais elevados da citocina pró‐inflamatória TNF‐α em pacientes com artrite reumatoide.ConclusãoOs achados do presente estudo sugerem que há associação entre os polimorfismos dos genes MTHFR C677T e LT‐α A252G e um risco aumentado de AR nessa amostra da população egípcia.AbstractBackgroundRheumatoid arthritis is a widely prevalent autoimmune disorder with suggested genetic predisposition.ObjectivesThe aim of this study is to detect the pattern of genetic polymorphism of methylene tetrahydrofolate reductase (MTHFR C677T and A1298C), transforming growth factor‐β1 (TGF‐β1 T869C) and lymphotoxin‐α (LT‐α A252G) in patients having rheumatoid arthritis and correlate these patterns to disease activity and serum levels of tumor necrosis factor‐alpha (TNF‐α), B‐Cell Activating Factor (BAFF), and osteopontin.MethodsA total of 194 subjects, 90 controls and 104 patients with rheumatoid arthritis were genotyped for MTHFR C677T and A1298C, TGF‐β1 T869C and LT‐α A252G polymorphisms using a methodology based on PCR‐RFLP. Also serum levels of TNF‐α, osteopontin and BAFF were measured by ELISA kits.ResultsThe CT genotype and T allele of MTHFR C677T and GG genotype and G allele of LT‐α A252G are associated with the risk of RA and with higher levels of the pro‐inflammatory cytokine, TNF‐α in patients with rheumatoid arthritis.ConclusionOur findings suggest that there is association between MTHFR C677T and LT‐α A252G genes polymorphisms and increased risk of RA in this sample of Egyptian population

Protective effects of some fruit juices with low-fat diet on rat testis damaged by carbon tetrachloride: A genetic and histological study

Oxidative stress, free radical, lipid peroxidation and antioxidant have become a common expression with most disease and methods for protection. Carbon tetrachloride (CCl4) is an industrial solvent which has destructive effects on a cell while most fruit juices have antioxidant effects. The aim of this study was to investigate the protective role of fruit juice on testis after toxic effect with CCl4 through oxidative stress with basal diet and low-fat diet. Seventy-five male albino rats were used for this study in which the juices of three fresh fruit, yellow apples (Malus domestica, L.), red grapes containing seeds (Vitis vinifera, L.) and pomegranates (Punica granatum, L.) were used as therapeutic agents. Histological sections of testis indicated that low-fat diet has obvious effects than basal diet in both the low-fat diet with CCl4 "LdC""con++", LdC with grape juice 2 ml "grpL2", LdC with pomegranate juice 2 ml "pomL2" and hyper effect in LdC with pomegranate juice 4 ml "pomL4" while it was equal in effect with basal diet in the other treatments. Low-fat diet gave significant effects (about 75% recovery in con++, LdC with Apple juice 2 ml and 4 ml "appL2, appL4" , LdC with grape juice 4 ml "grpL4" and pomL2) while 25% began to recover as shown in basal diet with pomegranate juice 4 ml "pomB4" and grpL2. Treatment of rats with pomegranate juice ameliorated the toxic effects of CCl4 with low-fat diet on Semi-random RAPD-DNA profile. Low-fat diet with fruit juice had positive effect against toxicity induced by CCl4 in testes of rats on the level of histological and DNA-RAPD studies.Key words: CCl4, rat testis, yellow apples, red grapes, pomegranates, low-fat diet, oxidative stress

Measuring the brightness temperature distribution of extragalactic radio sources with space VLBI

We have used VSOP space very long baseline interferometry observations to measure the brightness temperature distribution of a well-defined sub-set of the Pearson-Readhead sample of extragalactic radio sources. VLBI which is restricted to Earth-diameter baselines is not generally sensitive to emitting regions with brightness temperatures greater than approximately $10^{12}$ K, coincidentally close to theoretical estimates of brightness temperature limits, $10^{11} - 10^{12}$ K. We find that a significant proportion of our sample have brightness temperatures greater than $10^{12}$ K; many have unresolved components on the longest baselines, and some remain completely unresolved. These observations begin to bridge the gap between the extended jets seen with ground-based VLBI and the microarcsecond structures inferred from intraday variability, evidenced here by the discovery of a relationship between intraday variability and VSOP-measured brightness temperature, likely due to the effects of relativistic beaming. Also, lower limits on jet Lorentz factors, estimated from space VLBI observations, are starting to challenge numerical simulations that predict low Lorentz factor jets.Comment: 4 pages + 1 figure, ApJ letters, accepte

Effect of salinity on seed germination of Vigna marina a wild relative of crop Vigna species using hydrotime modelling

Vigna marina (Fabaceae) is a wild relative of cultivated Vigna species. Crop wild relatives are important genetic source, which can be utilized in developing desired crop varieties. V. marina is a vine, growing naturally in sandy seashore with high saline soil conditions and have the different threshold water potential effects on germination pattern rather non-salt tolerant Vigna species. Thus, salinity tolerant traits of V. marina can be utilized to develop salinity tolerant crop Vigna varietiesThe objective of the study was to study the salinity stress tolerance of V. marina seeds during germination using a hydrotime model. Healthy seeds of V. marina were extracted from randomly selected plants from coastal area of Southern Province of Sri Lanka. Germination and imbibitions of untreated and chemically scarified seeds were studied. Several acid scarification treatments were conducted to determine the best dormancy breaking treatment. Acid scarified seeds of V. marina and V. radiata were separately germinated in series of salt concentrations to develop a hydrotime model.Chemically scarified seeds of V. marina increased mass > 62% while, untreated seeds increased mass <21%. Chemically scarified seeds germinated 100% whereas, untreated seeds germinated 67% both at light and dark conditions. Results revealed that 5% of V. marina seeds have physical dormancy. Chemically scarified seeds for 5 minutes showed the highest germination which was > 85% and confirmed that chemical scarification for 5 minutes was the best dormancy breaking treatment. In Na2SO4 base water potential is [ψ b(60%)] -5.47 MPa and – 5.43 MPa for V. marina and V. radiate respectively. In KNO3 base water potentials are – 5.65 MPa and – 5.59 MPa for V. marina and V. radiata respectively. Lower base water potentials of V. marina seeds compared to base water potential of V. radiata indicate the salt tolerance ability of V. marina than the V. radiata. Therefore V. marina can be utilized to develop salt tolerant crop Vigna specie

Discovery of the Galaxy Proximity Effect and Implications for Measurements of the Ionizing Background Radiation at Low Redshifts

We present an analysis of galaxy and QSO absorption line pairs toward 24 QSOs at redshifts between z~0.2 and 1 in an effort to establish the relationship between galaxies and absorption lines in physical proximity to QSOs. We demonstrate the existence of a galaxy proximity effect, in that galaxies in the vicinities of QSOs do not show the same incidence and extent of gaseous envelopes as galaxies far from QSOs. We show that the galaxy proximity effect exists to galaxy-QSO velocity separations of ~ 3000 km/s, much larger than the size of a typical cluster (~ 1000 km/s), i.e. it is more comparable to the scale of the sphere of influence of QSO ionizing radiation rather than the scale of galaxy-QSO clustering. This indicates that the QSO ionizing radiation rather than some dynamical effect from the cluster environment is responsible for the galaxy proximity effect. We combine previous findings that (1) many or most Lya absorption lines arise in extended galaxy envelopes, and (2) galaxies cluster around QSOs to show that the magnitude of the Lya forest proximity effect is underestimated. Consequently, determinations of the UV ionizing background intensity using the proximity effect are likely overestimated. We use the galaxy-QSO cross-correlation function measured from our data to estimate the magnitude of this overestimate and find that it could be as high as a factor of 20 at z<1. This can have strong implications for models of the origin and evolution of the ionizing background, and may indicate that QSOs produce sufficient ionizing flux at all redshifts to account for the entire background radiation field.Comment: 26 pages, 3 figures, to appear in ApJ, October 20, 200

Semiparametric Multivariate Accelerated Failure Time Model with Generalized Estimating Equations

The semiparametric accelerated failure time model is not as widely used as the Cox relative risk model mainly due to computational difficulties. Recent developments in least squares estimation and induced smoothing estimating equations provide promising tools to make the accelerate failure time models more attractive in practice. For semiparametric multivariate accelerated failure time models, we propose a generalized estimating equation approach to account for the multivariate dependence through working correlation structures. The marginal error distributions can be either identical as in sequential event settings or different as in parallel event settings. Some regression coefficients can be shared across margins as needed. The initial estimator is a rank-based estimator with Gehan's weight, but obtained from an induced smoothing approach with computation ease. The resulting estimator is consistent and asymptotically normal, with a variance estimated through a multiplier resampling method. In a simulation study, our estimator was up to three times as efficient as the initial estimator, especially with stronger multivariate dependence and heavier censoring percentage. Two real examples demonstrate the utility of the proposed method

The Pearson-Readhead Survey of Compact Extragalactic Radio Sources From Space. II. Analysis of Source Properties

We have performed a multi-dimensional correlation analysis on the observed properties of a statistically complete core-selected sample of compact radio-loud active galactic nuclei, based on data from the VLBI Space Observing Programme (Paper I) and previously published studies. Our sample is drawn from the well-studied Pearson-Readhead (PR) survey, and is ideally suited for investigating the general effects of relativistic beaming in compact radio sources. In addition to confirming many previously known correlations, we have discovered several new trends that lend additional support to the beaming model. These trends suggest that the most highly beamed sources in core-selected samples tend to have a) high optical polarizations; b) large pc/kpc-scale jet misalignments; c) prominent VLBI core components; d) one-sided, core, or halo radio morphology on kiloparsec scales; e) narrow emission line equivalent widths; and f) a strong tendency for intraday variability at radio wavelengths. We have used higher resolution space and ground-based VLBI maps to confirm the bi-modality of the jet misalignment distribution for the PR survey, and find that the sources with aligned parsec- and kiloparsec-scale jets generally have arcsecond-scale radio emission on both sides of the core. The aligned sources also have broader emission line widths. We find evidence that the BL Lacertae objects in the PR survey are all highly beamed, and have very similar properties to the high-optically polarized quasars, with the exception of smaller redshifts. A cluster analysis on our data shows that after partialing out the effects of redshift, the luminosities of our sample objects in various wave bands are generally well-correlated with each other, but not with other source properties.Comment: 21 pages, 10 figures. Accepted for publication in the Astrophysical Journal. Part I can be found at astro-ph/010227