Identification and Characterization of Toxigenic Fusaria Associated with Sorghum Grain Mold Complex in India

Fusarium species are dominant within the sorghum grain mold complex. Some species of Fusarium involved in grain mold complex produce mycotoxins, such as fumonisins. An attempt was made to identify Fusarium spp. associated with grain mold complex in major sorghum-growing areas in India through AFLP-based grouping of the isolates and to further confirm the species by sequencing part of α-Elongation factor gene and comparing the sequences with that available in the NCBI database. The dendrogram generated from the AFLP data clustered the isolates into 5 groups. Five species of Fusarium—F. proliferatum, F. thapsinum, F. equiseti, F. andiyazi and F. sacchari were identified based on sequence similarity of α-Elongation factor gene of the test isolates with those in the NCBI database. Fusarium thapsinum was identified as predominant species in Fusarium—grain mold complex in India and F. proliferatum as highly toxigenic for fumonisins production. Analysis of molecular variance (AMOVA) revealed 54% of the variation in the AFLP patterns of 63 isolates was due to the differences between Fusarium species, and 46% was due to differences between the strains within a species.     

Hoechst 33342 induced reactive oxygen species and impaired expression of cytochrome c oxidase subunit 1 leading to cell death in irradiated human cancer cells

Oxidative stress and mitochondrial dysfunction in cancer cells represent features that may be exploited therapeutically. We determined whether minor groove binding ligand Hoechst 33342, known to induce mitochondrial dysfunction via increase in reactive oxygen species (ROS), enhances killing of human head and neck cancer (KB) cells mediated by impaired expression of mitochondrial protein involved in electron transfer. Elevation in ROS generation, increase in ΔΨm, down regulation of cytochrome c oxidase (CO), alteration in expression of antioxidant enzymes viz. Mn-SOD and Catalase, and release of cytochrome c into the cytosol, were observed in time-dependent manner when cells were irradiated (5 Gy) in presence of Hoechst 33342. Persistent increase in ROS observed till 48 h following treatment decreased the clonogenic survival and viability to a large extent via increase in ΔΨm, release of cytochrome c and non-coordinated expression of antioxidant enzymes. Treatment with antioxidants PEG-MnSOD and PEG-catalase inhibited the increase in ROS and loss of cell survival, suggesting the involvement of ROS in the Hoechst 33342-induced cell death. The result demonstrated significant sensitization of cancer cells to radiation-induced toxicity in presence of Hoechst 33342 via increasing ROS to a toxic level and impairing CO expression and antioxidant enzymes. This understanding is expected to benefit both in elucidating the detailed mechanisms of actions of DNA interacting drug and designing better molecules for enhancing radiation-induced cell death among cancer cells.     

The Escherichia coli clamp loader can actively pry open the β-sliding clamp

Clamp loaders load ring-shaped sliding clamps onto DNA. Once loaded onto DNA, sliding clamps bind to DNA polymerases to increase the processivity of DNA synthesis. To load clamps onto DNA, an open clamp loader-clamp complex must form. An unresolved question is whether clamp loaders capture clamps that have transiently opened or whether clamp loaders bind closed clamps and actively open clamps. A simple fluorescence-based clamp opening assay was developed to address this question and to determine how ATP binding contributes to clamp opening. A direct comparison of real time binding and opening reactions revealed that the Escherichia coli γ complex binds β first and then opens the clamp. Mutation of conserved "arginine fingers" in the γ complex that interact with bound ATP decreased clamp opening activity showing that arginine fingers make an important contribution to the ATP-induced conformational changes that allow the clamp loader to pry open the clamp.     

Evidence of Experimental Vertical Transmission of Emerging Novel ECSA Genotype of Chikungunya Virus in Aedes aegypti

Background

Chikungunya virus (CHIKV) has emerged as one of the most important arboviruses of public health significance in the past decade. The virus is mainly maintained through human-mosquito-human cycle. Other routes of transmission and the mechanism of maintenance of the virus in nature are not clearly known. Vertical transmission may be a mechanism of sustaining the virus during inter-epidemic periods. Laboratory experiments were conducted to determine whether Aedes aegypti, a principal vector, is capable of vertically transmitting CHIKV or not.

Methodology/Principal Findings

Female Ae. aegypti were orally infected with a novel ECSA genotype of CHIKV in the 2^nd gonotrophic cycle. On day 10 post infection, a non-infectious blood meal was provided to obtain another cycle of eggs. Larvae and adults developed from the eggs obtained following both infectious and non-infectious blood meal were tested for the presence of CHIKV specific RNA through real time RT-PCR. The results revealed that the larvae and adults developed from eggs derived from the infectious blood meal (2^nd gonotrophic cycle) were negative for CHIKV RNA. However, the larvae and adults developed after subsequent non-infectious blood meal (3^rd gonotrophic cycle) were positive with minimum filial infection rates of 28.2 (1∶35.5) and 20.2 (1∶49.5) respectively.

Conclusion/Significance

This study is the first to confirm experimental vertical transmission of emerging novel ECSA genotype of CHIKV in Ae. aegypti from India, indicating the possibilities of occurrence of this phenomenon in nature. This evidence may have important consequence for survival of CHIKV during adverse climatic conditions and inter-epidemic periods.     

Capacity optimization and scheduling of a multiproduct manufacturing facility for biotech products

A general mathematical framework has been proposed in this work for scheduling of a multiproduct and multipurpose facility involving manufacturing of biotech products. The specific problem involves several batch operations occurring in multiple units involving fixed processing time, unlimited storage policy, transition times, shared units, and deterministic and fixed data in the given time horizon. The different batch operations are modeled using state‐task network representation. Two different mathematical formulations are proposed based on discrete‐ and continuous‐time representations leading to a mixed‐integer linear programming model which is solved using General Algebraic Modeling System software. A case study based on a real facility is presented to illustrate the potential and applicability of the proposed models. The continuous‐time model required less number of events and has a smaller problem size compared to the discrete‐time model. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1221–1230, 2014