Toward a Fundamental Understanding of the Role of Lignin in the Biorefinery Process

As one of the main components in biomass, lignin plays a vital role in the biorefinery industry. Its unique structural feature increases the dose of cellulases during enzymatic deconstruction and is an attractive resource for many high valued products. The inhibition of lignin on cellulases is proposed to occur in several ways, with the most studied being nonproductive enzyme binding, which is attributed to hydrogen bonding, hydrophobic and/or electrostatic interactions. This review provides a comprehensive review of how lignin is transformed during various pretreatment methods as well as how these changes impact the cellulases inhibition. Future pretreatment directions for decreased cellulases inhibition are also proposed.

The prevailing O serogroups among the serologically differentiated clinical Proteus spp. strains in central Poland

In the years 2006–2011, 617 Proteus spp. strains isolated mostly from urine and wounds or other clinical sources were collected in Łódź, Poland, to determine the offensive O serotypes frequently occurring among patients. P. mirabilis exhibited the most intensive swarming growth and was dominating species (86.9%), followed by P. genomospecies, P. vulgaris, and P. penneri. Ninety four per cent strains were recognized as S (smooth) forms. Serological studies (involving ELISA—enzyme-linked immunosorbent assay and Western blotting using native and adsorbed rabbit antisera) enabled classification of 80% S isolates into respective Proteus O serogroups among the 83 ones, described so far. The remaining strains seemed to be serologically unique. Despite the observed big serological variety of Proteus spp. isolates, we found the O78 serogroup recently described in Poland as dominating and identified other widespread serotypes: O3, O6, O10, O11, O27, O28, and O30 reported earlier as predominating also in other countries; O77 and O79 detected lately in Poland; O16, O18, O20, and O50. No unique structural feature of the prevalent O serotypes has been indicated. However, the prevalence of some O serogroups indicates that particular serotypes may be in some ways beneficial to the strains producing these kinds of O antigen.

Formation of porous ice frameworks at room temperature

Bulk crystalline ices with ultralow densities have been demonstrated to be thermodynamically metastable at negative pressures. However, the direct formation of these bulk porous ices from liquid water at negative pressures is extremely challenging. Inspired by approaches toward porous media based on host–guest chemistry, such as metal–organic frameworks and covalent organic frameworks, we herein demonstrate via molecular dynamics simulations that a class of ultralow-density porous ices with upright channels can be formed spontaneously from liquid water at 300 K with the assistance of carbon nanotube arrays. We refer to these porous ice polymorphs as water oxygen-vertex frameworks (WOFs). Notably, our simulations revealed that the liquid–WOF phase transition is first-order and occurs at room temperature. All the WOFs exhibited the unique structural feature that they can be regarded as assemblies of nanoribbons of hexagonal bilayer ice (2D ice I) at their armchair or zigzag edges. Based on density functional theory calculations, a comprehensive phase diagram of the WOFs was constructed considering both the thermodynamic and thermal stabilities of the porous ices at negative pressures. Like other types of porous media, these WOFs may be applicable to gas storage, purification, and separation. Moreover, these biocompatible porous ice networks may be exploited as medical-related carriers.

Nuclear Translocation of SRPKs Is Associated with 5-FU and Cisplatin Sensitivity in HeLa and T24 Cells

Serine/arginine protein kinases (SRPKs) phosphorylate Arg/Ser dipeptide-containing proteins that play crucial roles in a broad spectrum of basic cellular processes. The existence of a large internal spacer sequence that separates the bipartite kinase catalytic core and anchors the kinases in the cytoplasm is a unique structural feature of SRPKs. Here, we report that exposure of HeLa and T24 cells to DNA damage inducers triggers the nuclear translocation of SRPK1 and SRPK2. Furthermore, we show that nuclear SRPKs did not protect from, but on the contrary, mediated the cytotoxic effects of genotoxic agents, such as 5-fluorouracil (5-FU) and cisplatin. Confirming previous data showing that the kinase activity is essential for the entry of SRPKs into the nucleus, SRPIN340, a selective SRPK1/2 inhibitor, blocked the nuclear accumulation of the kinases, thus diminishing the cytotoxic effects of the drugs. ATR/ATM-dependent phosphorylation of threonine 326 and serine 408 in the spacer domain of SRPK1 was essential for the redistribution of the kinase to the nucleus. Substitution of either of these two residues to alanine or inhibition of ATR/ATM kinase activity abolished nuclear localization of SRPK1 and conferred tolerance to 5-FU treatment. These findings suggest that SRPKs may play an important role in linking cellular signaling to DNA damage in eukaryotic cells.

The Prevailing O Serogroups Among the Serologically Differentiated Clinical Proteus Spp. Strains in Poland

In the years 2006-2011, 617 Proteus spp. strains isolated mostly from urine and wounds or other clinical sources from infected individuals were collected in Łódź, Poland. P. mirabilis species was dominating (86.9%), followed by P. genomospecies, P. vulgaris , and P. penneri . Ninety four per cent strains were recognized as S (smooth) forms. P. mirabilis exhibited the most intensive swarming growth. Serological studies (involving ELISA – enzyme-linked immunosorbent assay and Western blotting using native and adsorbed rabbit antisera) enabled classification of 80% S isolates into respective Proteus O serogroups among the 83 ones, described so far. The remaining strains seemed to be serologically unique. Detailed serological analysis confirmed that the recently described in Poland O78 serogroup is the most widespread. Also, 14 other serogroups have been found to predominate, being represented by ten or more strains. No unique structural feature of the prevalent O serotypes has been indicated. The observed big serological variety may suggest a low rate of Proteus spp. strains’ transmission between patients or rapid changes in their lipopolysaccharides. However, the prevalence of some O serogroups indicates that particular serotypes may be in some ways beneficial to the strains producing these kinds of O antigen.

A Review on the Synthesis and Biological Studies of 2,4-Thiazolidinedione Derivatives

2,4-Thiazolidinediones are versatile scaffolds with a unique structural feature of hydrogen bonding donor and the hydrogen bonding acceptor region. This review deals with the synthesis of various bio-active 2,4-thiazolidinedione derivatives. It is presented on the basis of the linker variations at 3rd & 5th positions of 2,4-thizolidinediones. Biological evaluations of various derivatives thus prepared and toxicity studies on the respective products as given by various researchers/ Research groups have been described.

Mycobacterium Survival Strategy Translated to Develop a Lipo-Peptide Based Fusion Inhibitor

The entry of enveloped viruses requires fusion of viral and host cell membranes. An effective fusion inhibitor aiming at impeding such virus-host cell membrane fusion may emerge as a broad-spectrum antiviral agent to neutralize the infection from an increasing diversity of harmful new viruses. Mycobacterium survives inside the phagosome of the host cells by inhibiting phagosome-lysosome fusion with the help of a coat protein coronin 1. Structural analysis of coronin 1 and other WD40-repeat containing protein suggest that the tryptophan-aspartic acid (WD) sequence is placed at distorted β-meander motif (more exposed) whereas the WD resides in regular β-meander motif in other WD40 proteins. The unique structural feature of coronin 1 was explored to identify a simple lipo-peptide sequence (lipid-WD), which effectively inhibit the membrane fusion by increasing interfacial order and decreasing water penetration, surface potential. The effective fusion inhibitory role of mycobacterium inspired lipo-dipeptide was applied to combat type 1 influenza virus (H1N1) infection as a ‘broad spectrum’ antiviral agent.<br>

Mycobacterium Survival Strategy Translated to Develop a Lipo-Peptide Based Fusion Inhibitor

The entry of enveloped viruses requires fusion of viral and host cell membranes. An effective fusion inhibitor aiming at impeding such virus-host cell membrane fusion may emerge as a broad-spectrum antiviral agent to neutralize the infection from an increasing diversity of harmful new viruses. Mycobacterium survives inside the phagosome of the host cells by inhibiting phagosome-lysosome fusion with the help of a coat protein coronin 1. Structural analysis of coronin 1 and other WD40-repeat containing protein suggest that the tryptophan-aspartic acid (WD) sequence is placed at distorted β-meander motif (more exposed) whereas the WD resides in regular β-meander motif in other WD40 proteins. The unique structural feature of coronin 1 was explored to identify a simple lipo-peptide sequence (lipid-WD), which effectively inhibit the membrane fusion by increasing interfacial order and decreasing water penetration, surface potential. The effective fusion inhibitory role of mycobacterium inspired lipo-dipeptide was applied to combat type 1 influenza virus (H1N1) infection as a ‘broad spectrum’ antiviral agent.<br>

Recent Advances and Applications of tert-Butyl Nitrite (TBN) in Organic Synthesis

This mini-review will present the recent applications of Tert-Butyl Nitrite (TBN) in organic synthesis. Due to its unique structural feature and wide application, TBN holds a prominent and great potential in organic synthesis. The applications of TBN in three areas viz. aerobic oxidation, annulation, and diazotization were reviewed recently; now, the current mini-review will describe the studies carried out to date in areas such as nitration of alkane, alkene, alkyne, and aromatic compounds, nitrosylation and sequential nitrosylation reactions, using TBN as source of oxygen and nitrogen. The mechanisms of these transformations will be briefly described in this mini-review.

Anchoring Cu1 species over nanodiamond-graphene for semi-hydrogenation of acetylene

The design of cheap, non-toxic, and earth-abundant transition metal catalysts for selective hydrogenation of alkynes remains a challenge in both industry and academia. Here, we report a new atomically dispersed copper (Cu) catalyst supported on a defective nanodiamond-graphene (ND@G), which exhibits excellent catalytic performance for the selective conversion of acetylene to ethylene, i.e., with high conversion (95%), high selectivity (98%), and good stability (for more than 60 h). The unique structural feature of the Cu atoms anchored over graphene through Cu-C bonds ensures the effective activation of acetylene and easy desorption of ethylene, which is the key for the outstanding activity and selectivity of the catalyst.