Bidirectional motility of kinesin-5 motor proteins: structural determinants,cumulative functions and physiological roles

Mitotic kinesin-5 bipolar motor proteins perform essential functions in mitotic spindle dynamics by crosslinking and sliding antiparallel microtubules (MTs) apart within the mitotic spindle. Two recent studies have indicated that single molecules of Cin8, the Saccharomyces cerevisiae kinesin-5 homolog, are minus end-directed when moving on single MTs, yet switch directionality under certain experimental conditions (Gerson-Gurwitz et al., EMBO J 30:4942–4954, 2011; Roostalu et al., Science 332:94–99, 2011). This finding was unexpected since the Cin8 catalytic motor domain is located at the N-terminus of the protein, and such kinesins have been previously thought to be exclusively plus end-directed. In addition, the essential intracellular functions of kinesin-5 motors in separating spindle poles during mitosis can only be accomplished by plus end-directed motility during antiparallel sliding of the spindle MTs. Thus, the mechanism and possible physiological role of the minus end-directed motility of kinesin-5 motors remain unclear. Experimental and theoretical studies from several laboratories in recent years have identified additional kinesin-5 motors that are bidirectional, revealed structural determinants that regulate directionality, examined the possible mechanisms involved and have proposed physiological roles for the minus end-directed motility of kinesin-5 motors. Here, we summarize our current understanding of the remarkable ability of certain kinesin-5 motors to switch directionality when moving along MTs.     

Systems,Design, and Entrepreneurial Thinking: Comparative Frameworks

The philosophies of design thinking, entrepreneurial thinking, and systems thinking have widespread application in diverse fields. However, due to the inherently abstract rhetoric and lack of commonly accepted frameworks, these philosophies are often considered buzzwords and fads. This article deconstructs the rhetoric and literature from leaders of these three philosophies and identifies their fundamental tenets. A conceptual framework that captures the differences and convergences between design thinking, entrepreneurial thinking, and systems thinking is presented. A series of four case studies derived from diverse settings like healthcare, agriculture, and social networks further illustrate these interconnections. The article argues that the emergent integration of these philosophies, as captured in the fundamental tenets, presents the most compelling opportunities for the practical application of these theoretical frameworks.     

Approaches to identify and characterize microProteins and their potential uses in biotechnology

MicroProteins are small proteins that contain a single protein domain and are related to larger, often multi-domain proteins. At the molecular level, microProteins act by interfering with the formation of higher order protein complexes. In the past years, several microProteins have been identified in plants and animals that strongly influence biological processes. Due to their ability to act as dominant regulators in a targeted manner, microProteins have a high potential for biotechnological use. In this review, we present different ways in which microProteins are generated and we elaborate on techniques used to identify and characterize them. Finally, we give an outlook on possible applications in biotechnology.     

New species of Eretmocerus Haldeman (Hymenoptera: Aphelinidae) parasitizing Crenidorsum turpiniae (Takahashi) and Aleurothrixus floccosus (Maskell) (Hemiptera: Aleyrodidae) from Taiwan

A key to females of 11 Eretmocerus species occurring in Taiwan is provided. Two new species, E. tongxiaoensis Shih & Polaszek, sp. nov. and E. lannae Shih & Polaszek, sp. nov. found infesting Crenidorsum turpiniae (Takahashi) and Aleurothrixus floccosus (Maskell) respectively, are described. Five more Eretmocerus species are recorded here as new to Taiwan: E. bisetae Hayat, E. flavus Krishnan & David, E. queenslandensis Naumann & Schmidt, E. rui Zolnerowich & Rose and E. trialeurodis Hayat. New host records for four of these Eretmocerus species from five whitefly species are presented. The whitefly Aleurothrixus floccosus (Maskell) is recorded for the first time from Taiwan.     

System Archetype to Understand Unintended Behavior in Indian Shrimp Industry and to Aid in Strategy Development

The Indian Shrimp Industry has exhibited an interesting phenomenon of fast growth in the early nineties (1990–1994), decline in the mid-nineties (1995–1997), and slow revival in the recent years (1997–2009). The cyclic behavior of the Industry, though, was much discussed in the literature, but no explanation regarding such behavior was explicitly discussed in the literature. The strategies following such behavior were mostly ad-hoc and symptomatic in nature. In this paper, we have analyzed the Industry’s past behavior using a systems approach and have developed the structure of the Industry in the form of a system archetype, which explained the cyclic behavior of the Industry. The system archetypical structure of the Industry was made keeping the existing system archetypes as the foundation. The system archetype developed here is generic enough to explain any growth-decline-revival behavior of an industry or organization. The archetype of Indian Shrimp Industry also helped us in designing sustainable strategies for the Industry that included controlling over-expansion in a shrimp farming zone and controlling pollution generation by each shrimp farm.     

From East to West- Has the Twain Met? Linkages Between Context Sensitivity and Soft Systems Methodology

This paper links context sensitivity of Indians to mode 2 of Soft Systems Methodology (SSM) bringing out the similarities between Gemeinschaft and Gesellschaft and the primary mode and secondary mode of behaviour of context sensitivity respectively. Both SSM and context sensitivity consider the totality of environment before selecting the most appropriate behaviour. In the Indian context, the three dimensions of context sensitivity—person (patra), time (kal) and ecology (the pattern of relationships people have with their social and physical surrounding) (desh) are the three coordinates along which SSM’s standard of facts and values change. The unbundling of the changing standard of SSM along the three dimensions of person, time and ecology and across the two polarities of Gemeinschaft and Gesellschaft provides a model which is used to explain the recent economic rise of India.An earlier and shorter version of this paper titled ‘Context sensitivity: An Indian version of soft systems’ has been presented at the ALARPM Congress 2006.     

The Actions of Mahabharat (an Indian Epic): An Analysis from Action Science Perspective

This paper analyses the actions of Mahabharat from the point of view of action science. From the point of view of action science, the source of the problem of Mahabharat is the undiscussable issue of who should be the king of Hastinapur. The paper then analyses the actions of different actors of this epic. It concludes that Yudhishthir displays the Model I governing value of ‘minimize generating or expressing negative feelings’. Duryodhan displays the Model I governing value of ‘maximize winning and minimize losing’. Vidur, Bhishm and Dronacharya display the Model I governing value of ‘be rational’. Together these actors create the ‘limited learning system’ of Model O-I. The primary inhibitory loops created by this limited learning system finally lead to secondary inhibitory loop of polarisation of different actors into two groups and the emergence of win-lose group dynamics in the form of war as the only action which can settle the original undiscussable issue of who should be the king of Hastinapur.     

EFFECTS OF PROCESSING OPERATIONS ON ZETA POTENTIAL AND CATIONIC DEMAND OF PULPS

Thc zeta potential and cationic demands of various kraft pulps - unbleached, bleached and beaten to different freeness levels were determined in the laboratory. The zeta potential of pulp where the final stage was a lignin degrading and dissolving treatment such as alkaline extraction or hypochlorite was lower than the unbleached pulp. The cationic demand of unbleached pulp was higher compared to that of bleached pulp. Beaten pulps showed larger cationic demands than the unbeaten pulps, which can be attributed to the larger specific surface area of pulp components. Fibres become increasingly electronegative when beaten and therefore cationic demand of pulps increases with beating. When the zeta potential method is used with furnishes of different freeness,the linear relationship is observed. However, the slope is decreasing with the decrease in freeness of the pulp.     

Effects of Sr2+ substitution on the structural,dielectric, and piezoelectric properties of PZT-PMN ceramics

This study described the structural, dielectric, and piezoelectric behavior of Pb_1?x Sr _x [(Zr_0.52Ti_0.48)_0.95(Mn_1/3Nb_2/3)_0.05]O₃ ceramics (PSZT-PMN, x = 0, 0.025, 0.050, and 0.075), prepared by a semi-wet route. X-ray diffraction, dielectric, and piezoelectric investigations were carried out to analyze the crystal structure. The relative dielectric constant and dielectric loss were both calculated as the functions of temperature. The room-temperature dielectric constant reaches a maximum for a Sr²⁺-modified PZT-PMN ceramic with an x value of 0.050, which corresponds to the morphotropic phase boundary (MPB). Raman spectroscopy studies also confirm the existence of this MPB for x = 0.050. The piezoelectric strain coefficients (d ₃₃) value shows a maximum response for this composition. In addition, the phase transition temperature decreases significantly when the Sr²⁺ concentration increases in the PZT-PMN ceramics.