Bidirectional motion of filaments: Role of motor proteins and passive cross linkers

In eukaryotic cells, motor proteins (MP) bind to cytoskeletal filaments and move along them in a directed manner generating active stresses. During cell division a spindle structure of overlapping antiparallel microtubules (MT) form whose stability and dynamics under the influence of MPs has been studied extensively. Although passive cross linkers (PCL) were known to provide structural stability to filamentous network, consequences of the interplay between ATP dependent active forces of MPs and passive entropic forces of PCLs on MT overlap remains largely unexplored. Here, we formulate and characterize a model to study this, using linear stability analysis and numerical integration. In presence of PCLs, we find dynamic phase transitions with changing activity exhibiting regimes of stable partial overlap with or without oscillations, instability towards complete overlap, and stable limit cycle oscillations that emerge via a supercritical Hopf bifurcation characterized by an oscillation frequency determined by the MP and PCL parameters. We show that the overlap dynamics and stability depend crucially on whether both the MTs of overlapping pair are movable or one is immobilized, having potential implications for in vivo and in vitro studies.Comment: 13 pages, 9 figure

Seed storage studies in Mesua ferrea L. a medicinal tree of Indo-Malayan region

This paper, deals with testing the storage and viability of the seeds of Mesua ferrea L. in 5 different storage conditions. Seeds of M. ferrea are recalcitrant in nature and lose viability with a short span 8-15 days. Of the different conventional methods tried using the polycarbonate bottle and bags, M. ferrea seeds retained viability for 150 days with a slow moisture loss from the seeds stored in closed polycarbonate bottles at 10 °C. Here, we have standardised a conventional technique whereby the viability of the seeds can be extended to 150-180 days by storing the seeds in polycarbonate bottles at 10 °C

Polymerization of Phenol using Free and Immobilized Horseradish Peroxidase

Phenol is a toxic compound and need to be treated before discharged. Phenol polymerization has been studied using free and immobilized Horse Radish Peroxidase (HRP). During the study period the ambient room temperature was between 27-32oC. Phenol concentration of 100-500 mg/L was fed to both free and immobilized HRP. Free enzyme studies were carried out in Erlenmayer flasks. Immobilized HRP Enzyme Bed Reactor was fabricated and used for polymerization of phenol. Free HRP polymerized 84% of phenol when fed with 100 mg/L where as Immobilized HRP polymerized 62% with the same phenol concentration. Free enzyme showed a better polymerization effect than immobilized enzyme. This might be attributed to the availability of more active sites in free enzyme when compared to immobilized enzymes. Reduction in phenol polymerization could be noticed with the increase in phenol concentration. Keywords: Phenol, phenol polymerizing enzymes, horse radish peroxidase, enzyme immobilization, bioremediation

Comparative morphology and phenetics of Nymphoides species in Kerala

Aquatic plants play an important role in maintaining the ecosystem balance. Nymphoides Seguier (Menyanthaceae) is an emergent, rhizomatous or stoloniferous genus, commonly known as “floating hearts”, identified by its rounded or cordate, floating leaves, petiole like branches and unique floral characters. The present study deals with the comparative morphology and the phenetics of Nymphoides spp. in Kerala. These species are classified into two groups with the help of the dendrogram, which showed 66% dissimilarities among the two groups. N. parvifolia and N. balakrishnanii are closely related species in one group and N. krishnakesara and N. macrosperma are closely related species in other group

Perception of Operators on Waste Management Systems in Desalination Plants in the United Arab Emirates

The technique of desalinating saltwater is one of the most practical ways to meet the growing need for freshwater in the Gulf countries, especially in the United Arab Emirates (UAE). Desalination offers great benefits in terms of the economy, society, and health; however, there are also negative effects on the environment because of uncontrolled waste disposal. The study aims to determine the perception of operators on waste management systems in desalination plants in the UAE. This study adopted a descriptive research design for collecting data about the impact of unregulated wastewater management and types of unregulated wastes using naturalistic observation and survey. The quantitative data was collected from the respondents using structured and close-ended questionnaires with a 4-point Likert scale. A simple random sampling method was used for selecting respondents in desalination plants. About 150 respondents were included in the study to get their perception of existing control measures and the development of innovative ideas or technology to control the brine impact and contribution of desalination plants to the development of waste management systems in the UAE. Data analysis was done using statistical tools like Chi-square. The results of this study showed that solar power plants benefit the UAE's people and economy. It was also observed that UAE desalination plants kept on trying new techniques like reverse osmosis (RO) and electro dialysis (ED) to reduce the levels of waste production and safeguard the natural surroundings. Hence, UAE desalination plants must adopt proper techniques and waste disposal methods to dispose of harmful brine, which will help preserve and safeguard the environment. It was found that the UAE is taking initiatives to treat and regulate brine discharge from desalination plants in order to provide citizens with safe and clean drinking water. However, the rejected brine and other waste liquids have a negative impact on the marine ecosystem

Treatment of Sewage by using Two-Stage Rotating Biological Contactor (RBC)

The rotating biological contactor (RBC) process offers the specific advantages of a bio-film system in treatment of wastewater for removal of soluble organic substance. The present review of RBC focus on parameter like materials used in fabrication of RBC Unit, media used for development of bio-film, HRT, organic and hydraulic loading rate, influent wastewater characteristics, Analysis treated wastewater characteristics, submergence variation, constant RPM, sizing of the reactor. In present study, a lab scale two stage RBC reactor is fabricated to treat sewage. Here work is carried out to check the performance and efficiency of two stage RBC reactor to treat sewage by varying submergence and maintaining constant speed (RPM).From present study, the two stages RBC is varied with 2 submergences for constant speed of disc as 4 RPM with different COD loading rate at optimum HRT. The result obtained when the disk submergence was 40%, the COD removal efficiency for tank1 was 90.31% and for tank1+tank2 were 93.8%. Hence optimum COD loading rate was 640 mg/L at optimum 2hrs HRT and when the disk submergence was 45%, the COD removal efficiency for tank1 was 90.76 % and for tank1+tank2 were 94.6 %. Hence optimum COD loading rate was 520 mg/L at optimum HRT of 1 hr. Keywords: Two stage Rotating Biological contactor (RBC), sewage, Optimum COD Loading Rate and HRT

In silico Characterization of Industrial Important Cellulases using Computational Tools

Cellulases refer to a class of enzymes produced majorly by fungi, bacteria and protozoans that catalyze cellulolysis. Cellulase enzyme is used extensively in various industries, especially in textile, food and in the bioconversion of lignocellulosic wastes to alcohol. The extensive use of cellulase in industries depends on the cost of the enzyme and hence considerable research is being carried out to isolate better microbial strains and also to develop new fermentation processes with the aim to reduce the product cost. Cellulases from different strains of Pseudomonas species were analyzed using computational tools. The physicochemical properties of the selected cellulases were analyzed by using ExPASy’s ProtParam tool and it was found that the molecular weight (M.Wt) ranges between 40927.4-100058.7 Da. Isoelectric Points (pI) of all the organisms were found to be acidic in nature. The aliphatic index infers that all the cellulases are stable. The negative value of GRAVY indicates that there will be better interaction with water. The secondary structure prediction was done by SOPMA which showed that random coils dominated all the other conformations. Multiple sequence analysis and evolutionary analysis of cellulases were carried out by CLC workbench. The Phylogenetic analysis was done using Neighbour joining method. The 3D structures of cellualses were obtained by ESyPred 3D server. Keywords: Cellulases, Enzymes, ProtParam, SOPMA, ESyPred 3D

Identification and mapping of yield and yield related QTLs from an Indian accession of Oryza rufipogon

BACKGROUND: Cultivated rice (Oryza sativa L.) is endowed with a rich genetic variability. In spite of such a great diversity, the modern rice cultivars have narrow genetic base for most of the agronomically important traits. To sustain the demand of an ever increasing population, new avenues have to be explored to increase the yield of rice. Wild progenitor species present potential donor sources for complex traits such as yield and would help to realize the dream of sustained food security. RESULTS: Advanced backcross method was used to introgress and map new quantitative trait loci (QTLs) relating to yield and its components from an Indian accession of Oryza rufipogon. An interspecific BC(2) testcross progeny (IR58025A/O. rufipogon//IR580325B///IR58025B////KMR3) was evaluated for 13 agronomic traits pertaining to yield and its components. Transgressive segregants were obtained for all the traits. Thirty nine QTLs were identified using interval mapping and composite interval mapping. In spite of it's inferiority for most of the traits studied, O. rufipogon alleles contributed positively to 74% of the QTLs. Thirty QTLs had corresponding occurrences with the QTLs reported earlier, indicating that these QTLs are stable across genetic backgrounds. Nine QTLs are novel and reported for the first time. CONCLUSION: The study confirms that the progenitor species constitute a prominent source of still unfolded variability for traits of complex inheritance like yield. With the availability of the complete genome sequence of rice and the developments in the field of genomics, it is now possible to identify the genes underlying the QTLs. The identification of the genes constituting QTLs would help us to understand the molecular mechanisms behind the action of QTLs

Formation of a nickel hydroxide monolayer on Au through a self-assembled monolayer of 5,5'-dithiobis(2-nitrobenzoic acid): voltammetric, SERS and XPS investigations of the modified electrodes

The formation of self-assembled monolayers (SAM) of 5,5'-dithiobis (2-nitrobenzoic acid), DNBA on gold has enabled further derivatization of the electrode surface with functional moieties anchored to the surface bound molecules. A SAM of DNBA was formed on the Au surface. Nickel ions tethered to the SAM-covered Au surface, were subsequently derivatized electrochemically to yield nickel hydroxide overlayers, thereby showing the possibility of preparing ultra-thin films of metal oxides through solution chemistry. The nickel hydroxide surface coverage obtained on bare and SAM-covered electrodes was estimated from voltammetric peaks and it varied from one monolayer to about 300 monolayers. The formation of a monolayer of nickel hydroxide has been achieved for the first time by electrochemical modification. Further, the modified electrodes were subjected to SERS and XPS studies to understand their surface characteristics. Modified electrodes provide a catalytic pathway involving nickel hydroxide for the electro-oxidation of glucose in alkaline solutions

Coupled Phonons, Magnetic Excitations and Ferroelectricity in AlFeO3: Raman and First-principles Studies

We determine the nature of coupled phonons and magnetic excitations in AlFeO3 using inelastic light scattering from 5 K to 315 K covering a spectral range from 100-2200 cm-1 and complementary first-principles density functional theory-based calculations. A strong spin-phonon coupling and magnetic ordering induced phonon renormalization are evident in (a) anomalous temperature dependence of many modes with frequencies below 850 cm-1, particularly near the magnetic transition temperature Tc ~ 250 K, (b) distinct changes in band positions of high frequency Raman bands between 1100-1800 cm-1, in particular a broad mode near 1250 cm-1 appears only below Tc attributed to the two-magnon Raman scattering. We also observe weak anomalies in the mode frequencies at ~ 100 K, due to a magnetically driven ferroelectric phase transition. Understanding of these experimental observations has been possible on the basis of first-principles calculations of phonons spectrum and their coupling with spins