Kinetic study on starch hydrolysis using a glucose/maltose sensing system

Summary A dual-enzyme electrode flow injection system that can simultaneously determine glucose and maltose is used for an on-line study of starch hydrolyses catalysed by amylases. With the working system, determinations can be made every 2 minutes. A 10 L sample size with recycled back-flow minimises any loss of the reaction medium. The production, growth and decay of glucose and maltose concentrations during starch hydrolysis under various enzymatic conditions can thus be closely monitored, making it useful for the study of the catalytic kinetics of amylases and in screening and analysing enzyme systems.     

Mapping the Distribution of Anthrax in Mainland China, 2005–2013

BackgroundAnthrax, a global re-emerging zoonotic disease in recent years is enzootic in mainland China. Despite its significance to the public health, spatiotemporal distributions of the disease in human and livestock and its potential driving factors remain poorly understood.Conclusions/SignificanceAnthrax in China was characterized by significant seasonality and spatial clustering. The spatial distribution of human anthrax was largely driven by livestock husbandry, human density, land cover, elevation, topsoil features and climate. Enhanced surveillance and intervention for livestock and human anthrax in the high-risk regions, particularly on the Qinghai-Tibetan Plateau, is the key to the prevention of human infections.     

Eco-hydrological effects of landscape pattern change

Scientists and environmental managers alike are increasingly concerned about landscape pattern change and its effect on hydrological and ecological processes. In this paper, research progress is reviewed and key issues of eco-hydrological effects of landscape pattern change are discussed. There are different eco-hydrological effects with landscape pattern change, and most attention is paid to runoff, water quality, and soil loss. Landscape shape and spatial distribution can change precipitation-runoff processes and lead to the change in runoff yield. Water quality is closely connected with the composition and spatial pattern of source and sink landscapes. Soil erosion systems are usually modified by land use structure and landscape pattern, and soil loss will be either reduced or increased with land use change. In addition, the change of landscape pattern also has potential impacts on climate and soil quality. In future studies, more attention should be paid to comprehensive multi-scale and integrated research of landscape pattern and eco-hydrological processes.     

Selection and validation of suitable reference genes for miRNA expression normalization by quantitative RT-PCR in citrus somatic embryogenic and adult tissues

miRNAs have recently been reported to modulate somatic embryogenesis (SE), a key pathway of plant regeneration in vitro. For expression level detection and subsequent function dissection of miRNAs in certain biological processes, qRT-PCR is one of the most effective and sensitive techniques, for which suitable reference gene selection is a prerequisite. In this study, three miRNAs and eight non-coding RNAs (ncRNA) were selected as reference candidates, and their expression stability was inspected in developing citrus SE tissues cultured at 20, 25, and 30?°C. Stability of the eight non-miRNA ncRNAs was further validated in five adult tissues without temperature treatment. The best single reference gene for SE tissues was snoR14 or snoRD25, while for the adult tissues the best one was U4; although they were not as stable as the optimal multiple references snoR14?+?U6 for SE tissues and snoR14?+?U5 for adult tissues. For expression normalization of less abundant miRNAs in SE tissues, miR3954 was assessed as a viable reference. Single reference gene snoR14 outperformed multiple references for the overall SE and adult tissues. As one of the pioneer systematic studies on reference gene identification for plant miRNA normalization, this study benefits future exploration on miRNA function in citrus and provides valuable information for similar studies in other higher plants. Key message Three miRNAs and eight non-coding RNAs were tested as reference candidates on developing citrus SE tissues. Best single references snoR14 or snoRD25 and optimal multiple references snoR14?+?U6, snoR14?+?U5 were identified.     

Synthesis of (aminoalkyl)cycleanine analogues: cytotoxicity,cellular uptake,and apoptosis induction in ovarian cancer cells

Our previous studies demonstrated that cycleanine, a macrocyclic bisbenzylisoquinoline (BBIQ) alkaloid, showed potent anti-ovarian cancer activity via apoptosis induction. Here, we synthesized two novel (aminoalkyl)cycleanine analogues (2 and 3) through a simple and efficient two-step reaction starting from cycleanine isolated from Triclisia subcordata Oliv. These analogues showed greater potency than the unmodified cycleanine in three human ovarian cancer cell lines. Both 2 and 3 induced apoptosis in ovarian cancer cells by activations of caspases 3/7, cleavage of PARP, increase in subG₁ cell cycle phase and in the percentage of apoptotic cells. Further confocal fluorescence microscopy analysis confirmed the cellular uptake of alkaloids in ovarian cancer cells by using the unique (alkynyl)cycleanine (3) via click chemistry reaction. Our results suggest that cycleanine could be a hit compound for the future development in attacking ovarian cancer.