Lipase production by Serratia marcescens strain SN5gR isolated from the scat of lion-tailed macaque (Macaca silenus) in Silent Valley National Park, a biodiversity hotspot in India

An extracellular lipase-producing bacterium was isolated from a fecal sample of lion-tailed macaque (Macaca silenus), an endangered Old World monkey that is endemic to the Western Ghats of South India. Morphological, biochemical and molecular analyses identified the bacterium as Serratia marcescens. Production of lipase was investigated in shake-flask culture. Optimum tributyrin concentration of 1.5 % was found to be the most suitable triglyceride to increase lipase production (13.3 U ml^?1). The next best lipid source observed was olive oil (11.94 U ml^?1), followed by castor oil, coconut oil and palm oil. Analyzing the effect of different carbon sources on lipase production revealed that 2 % glucose yielded higher lipase production than the other tested carbon sources. Investigations on suitable nitrogen source for lipase production revealed that 2 % meat extract yielded higher lipase production. The most suitable trace element for maximum lipase production was zinc sulfate, followed by magnesium sulfate and copper sulfate. Partial characterization of the crude lipase revealed that pH 7.0 and a temperature of 40 °C gave optimal lipase activity. Enzymatic activity of the crude sample was retained over a wide temperature range (20–75 °C), and 70 % of enzyme activity was retained at 60 °C. Testing the effect of various organic solvents on lipase activity revealed that hexadecane increased lipase activity by 85 % over the control.     

Methodologies to decipher the cell secretome

The cell secretome is a collection of proteins consisting of transmembrane proteins (TM) and proteins secreted by cells into the extracellular space. A significant portion (~ 13–20%) of the human proteome consists of secretory proteins. The secretory proteins play important roles in cell migration, cell signaling and communication. There is a plethora of methodologies available like Serial Analysis of Gene Expression (SAGE), DNA microarrays, antibody arrays and bead-based arrays, mass spectrometry, RNA sequencing and yeast, bacterial and mammalian secretion traps to identify the cell secretomes. There are many advantages and disadvantages in using any of the above methods. This review aims to discuss the methodologies available along with their potential advantages and disadvantages to identify secretory proteins. This review is a part of a Special issue on The Secretome. This article is part of a Special Issue entitled: An Updated Secretome.     

A computational approach to design energetic ionic liquids

The present work deals with the theoretical estimation of ion-pair binding energies and the energetic properties of four ion pairs formed by combining the 1-butyl-2,4-dinitro-3-methyl imidazolium ion with nitrate (I), perchlorate (II), dinitramide (III), or 3,5-dinitro-1,2,4-triazolate (IV) anions. The counterpoise-corrected ion-pair binding energies were calculated for each ion pair at the B3LYP/6-311+G(d,p) level of theory. Results show that the cation–anion interaction is strongest for ion pair I and weakest for IV, indicating that the nitrate (I) has a greater tendency to exist as a stable ionic salt whereas the 3,5-dinitro-1,2,4-triazolate (IV) may exist as an ionic liquid. Natural bond orbital (NBO) analysis and electrostatic potential (ESP) mapping revealed that charge transfer occurs in all of the ion pairs, but is greatest (0.25e) for ion pair I and smallest (0.03e) for IV, resulting in ion pair I being the least polarized. A nucleus-independent chemical shift (NICS) study revealed that the aromaticity of the 1-butyl-2,4-dinitro-3-methyl imidazolium ion significantly increases in ion pair IV, indicating that this has the greatest charge delocalization among all of the four ion pairs considered. Studies of thermodynamic and detonation properties showed that ion pair II is the most energetic ion pair in terms of its detonation velocity (D = 7.5 km s^?1) and detonation pressure (P = 23.1 GPa). It is also envisaged that ion pair IV would exist as an energetic azolium azolate type ionic liquid that could be conveniently used as a secondary explosive characterized by detonation parameters D and P of 6.9 km s^?1 and 19.3 GPa, respectively. These values are comparable to those of conventional explosives such as TNT.     

In vitro morphogenesis in Selaginella microphylla (Kunth.) Spring

Selaginella, an extant genus of primitive vascular plants, has survived over 400 million years of evolution. In vitro morphogenesis in Selaginella microphylla is considered for the first time to establish a well-documented aseptic culture on half- strength Murashige and Skoog’s basal medium with 2ip (4.92–49.21 μM), or Kn (4.65–46.47 μM) or GA₃ (2.89–28.90 μM) for shoot multiplication, and with different concentrations of IBA (4.9–49 μm) to initiate root cultures. GA₃ was instrumental for shoot multiplication as well as induction of reproductive structures in each and every leaf axil. On the other hand, it is observed that IBA alone in S. microphylla can act as signal molecules for induction of enormous numbers of root masses from a few existing roots. An interesting pattern of re-differentiation has also been observed where apical portions of large numbers of roots were converted to green shoot apical meristems. Further differentiation produced tiny green shoots. Distinct bipolarity was noted in shoots when they were isolated from root masses and appeared as embryo-like structures. Chromosome analysis from in vitro sporophytic plants revealed 2n = 16 chromosomes, indicating chromosomal stability. The interesting in vitro pattern of morphogenesis obtained in S. microphylla may provide new insights into totipotency of plants.