Physiological studies on dormancy in grape seeds (Vitis vinifera var. Black Muscat) II. On the effect of exogenous application of growth substances, low chilling temperature and subjection of the seeds to running water

In order to break the dormancy of grape seeds in the minimum possible time, a number of treatments, including stratification, growth substances and subjecting the seeds to running water, were used. It was observed that grape seeds kept in running water for 8 days germinated in the muslin cloth itself (34.00%). The maximum percentage of germination obtained was 73.00% when the seeds were kept in running water for 16 days. However, the seedling stand was best under the 12 day treatment (72.11 %). This was followed by GA3 treatment (2000 ppm) before stratification, whereby grape seeds germinated within 8 days of stratification and maximum germination percentage was 81.05 after one month. Third best result was obtained under stratification for one month and then a treatment with GA3. Further, grape seeds, when soaked in water for 96 hours, leached some water soluble inhibitor. This could antagonize the germination of GA3 treated grape seeds. When this leached water was bioassayed by the cress seed germination test, it showed the presence of inhibitor at R1 0.7 to 0.85. It appears that the water soluble inhibitor might be responsible for masking the effect of growth substances present in the seeds and thereby disturbing the metabolism of germination.Physiologische Untersuchungen zur Dormanz von Rebensamen (Vitis vinifera var. Black Muscat). II. Über den Einfluß äußerlich angewandter Wuchsstoffe, niedriger Temperaturen und des Auswaschens der Samen in fließendem WasserUm die Dormanz von Rebensamen in der kürzestmöglichen Zeit zu brechen, wurden sie stratifiziert, mit Wuchsstoffen behandelt und in fließendem Wasser ausgewaschen. Es wurde beobachtet, daß Rebensamen, die in einem Musselinsäckchen 8 Tage lang ausgewaschen wurden, schon in dem Säckchen keimten (34,00°/o). Der h öchste Keimungsprozentsatz (73,000/o) wurde erzielt, wenn die Samen 16 Tage lang mit fließendem Wasser behandelt wurden. Bei einer 12tägigen Behandlung (72, 11% gekeimter Samen) war die Standfestigkeit der Sämlinge jedoch am besten. Das zweitbeste Resultat wurde mit GS3-Behandlung (2000 ppm) vor der Stratifikation erzielt, wobei die Rebensamen nach 8tägiger Stratifikation keimten; der höchste Anteil gekeimter Samen betrug - nach 30tägiger Stratifikation - 81,05%. 1monatige Stratifikation mit an schließender GS3-Behandlung lieferte das drittbeste Ergebnis. Ferner gaben Rebensamen, die 96 Std. lang in Wasser gequollen waren , einen wasserlöslichen Inhibitor ab. Dieser konnte die Keimung GS3-behandelter Samen hemmen. Mit Hilfe des Kressewurzeltests ließ sich im Einweichwasser ein Hemmstoff mit ein em Rr von 0,70-0,85 nachweisen. Möglicherweise stört der wasserlösliche Inhibitor den Stoffwechsel der Keimung, so daß die Wirkung der Wuchsstoffe in den Samen verdeckt wird

Prevalence of asthma in urban and rural children in Tamil Nadu

Background. There are very few community-based studies on the prevalence of asthma in Indian children. We aimed to estimate the prevalence of asthma in children under 12 years of age and to study possible differences in the prevalence of childhood asthma in urban and rural areas of Tamil Nadu. Methods. A total of 584 children from Chennai and 271 children from 25 villages around Chennai formed the urban and rural groups, respectively. From November 1999 to February 2000, data were collected using a simplified version of the ISAAC questionnaire, which was administered by trained students. Symptoms suggestive of asthma or hyperreactive airways disease in children under 12 years of age were recorded from the selected urban and rural populations by questioning the parents. The results were analysed separately for children 0-5 and 6-12 years of age. Results. Of the 855 children studied, the overall prevalence of breathing difficulty (including asthma) was 18% and the prevalence of ‘diagnosed’ asthma was 5%. Twenty-two per cent of urban and 9% of rural children 6-12 years of age reported breathing difficulty ‘at any time in the past’ (p<0.01). A significantly higher proportion of 6-12-year-old urban children also reported nocturnal dry cough (28.4%v. 18.7%,p<0.05). Urban children reported recent wheeze more often than rural children (92% v. 77%, p=0.01). Conclusions. Symptoms suggestive of asthma were present in 18% of children under 12 years of age. Though the prevalence of diagnosed childhood asthma was about 5% in both urban and rural areas, the prevalence of ‘breathing difficulty’ and nocturnal cough was significantly higher among urban children in the age group of 6-12 years. Children living in urban areas also reported ‘recent wheeze’ more often than rural children. Our data suggest that the actual prevalence of asthma and other ‘wheezy’ illnesses may be higher than that previously documented. Further studies are needed to confirm the difference in prevalence between urban and rural children and also to identify possible causes that could account for the higher urban prevalence of asthma in Tamil Nadu

Physicochemical characterization and in vitro dissolution studies of solid dispersions of ketoprofen with PVP K30 and d-mannitol

AbstractAim of the present study was to improve the solubility and dissolution rate of poorly water soluble, BCS class-II drug Ketoprofen (KETO) by solid-dispersion approach. Solid dispersions were prepared by using polyvinylpyrrolidone K30 (PVP K30) and d-mannitol in different drugs to carrier ratios. Dispersions with PVP K30 were prepared by kneading and solvent evaporation techniques, whereas solid dispersions containing d-mannitol were prepared by kneading and melting techniques. These formulations were characterized in the liquid state by phase-solubility studies and in the solid state by Differential Scanning Calorimetry (DSC), Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The aqueous solubility of KETO was favored by the presence of both carriers. The negative values of Gibbs free energy illustrate the spontaneous transfer from pure water to the aqueous polymer environment. Solid state characterization indicated KETO was present as fine particles in d-mannitol solid dispersions and entrapped in carrier matrix of PVP K30 solid dispersions. In contrast to the very slow dissolution rate of pure KETO, dispersions of drug in carriers considerably improved the dissolution rate. This can be attributed to increased wettability and dispersibility, as well as decreased crystallinity and increase in amorphous fraction of drug. Solid dispersions prepared with PVP K30 showed the highest improvement in dissolution rate of KETO. Even physical mixtures of KETO prepared with both carriers also showed better dissolution profiles than those of pure KETO

Effects of Molecular Crowding on stretching of polymers in poor solvent

We consider a linear polymer chain in a disordered environment modeled by percolation clusters on a square lattice. The disordered environment is meant to roughly represent molecular crowding as seen in cells. The model may be viewed as the simplest representation of biopolymers in a cell. We show the existence of intermediate states during stretching arising as a consequence of molecular crowding. In the constant distance ensemble the force-extension curves exhibit oscillations. We observe the emergence of two or more peaks in the probability distribution curves signaling the coexistence of different states and indicating that the transition is discontinuous unlike what is observed in the absence of molecular crowding.Comment: 14 pages, 6 figure

In search of a theory of supercooled liquids

Despite the absence of consensus on a theory of the transition from supercooled liquids to glasses, the experimental observations suggest that a detail-independent theory should exist.Comment: Commentary. 3 pages 2 figure

A new microscopic nucleon-nucleon interaction derived from relativistic mean field theory

A new microscopic nucleon-nucleon (NN) interaction has been derived for the first time from the popular relativistic mean field theory (RMFT) Lagrangian. The NN interaction so obtained remarkably relate to the inbuilt fundamental parameters of RMFT. Furthermore, by folding it with the RMFT-densities of cluster and daughter nuclei to obtain the optical potential, it's application is also examined to study the exotic cluster radioactive decays, and results obtained found comparable with the successfully used M3Y phenomenological effective NN interactions. The presently derived NN-interaction can also be used to calculate a number of other nuclear observables.Comment: 4 Pages 2 Figure

Bacterial ACC deaminase: Insights into enzymology, biochemistry, genetics, and potential role in amelioration of environmental stress in crop plants

Growth and productivity of crop plants worldwide are often adversely affected by anthropogenic and natural stresses. Both biotic and abiotic stresses may impact future food security and sustainability; global climate change will only exacerbate the threat. Nearly all stresses induce ethylene production in plants, which is detrimental to their growth and survival when present at higher concentrations. Consequently, management of ethylene production in plants is becoming an attractive option for countering the stress hormone and its effect on crop yield and productivity. In plants, ACC (1-aminocyclopropane-1-carboxylate) serves as a precursor for ethylene production. Soil microorganisms and root-associated plant growth promoting rhizobacteria (PGPR) that possess ACC deaminase activity regulate growth and development of plants under harsh environmental conditions by limiting ethylene levels in plants; this enzyme is, therefore, often designated as a “stress modulator.” TheACC deaminase enzyme, encoded by the AcdS gene, is tightly controlled and regulated depending upon environmental conditions. Gene regulatory components of AcdS are made up of the LRP protein-coding regulatory gene and other regulatory components that are activated via distinct mechanisms under aerobic and anaerobic conditions. ACC deaminase-positive PGPR strains can intensively promote growth and development of crops being cultivated under abiotic stresses including salt stress, water deficit, waterlogging, temperature extremes, and presence of heavy metals, pesticides and other organic contaminants. Strategies for combating environmental stresses in plants, and improving growth by introducing the acdS gene into crop plants via bacteria, have been investigated. In the recent past, some rapid methods and cutting-edge technologies based on molecular biotechnology and omics approaches involving proteomics, transcriptomics, metagenomics, and next generation sequencing (NGS) have been proposed to reveal the variety and potential of ACC deaminase-producing PGPR that thrive under external stresses. Multiple stress-tolerant ACC deaminase-producing PGPR strains have demonstrated great promise in providing plant resistance/tolerance to various stressors and, therefore, it could be advantageous over other soil/plant microbiome that can flourish under stressed environments