The zinc cluster protein Sut1 contributes to filamentation in Saccharomyces cerevisiae

Copyright © 2013, American Society for Microbiology. All Rights ReservedSut1 is a transcriptional regulator of the Zn(II)(2)Cys(6) family in the budding yeast Saccharomyces cerevisiae. The only function that has been attributed to Sut1 is sterol uptake under anaerobic conditions. Here, we show that Sut1 is also expressed in the presence of oxygen, and we identify a novel function for Sut1. SUT1 overexpression blocks filamentous growth, a response to nutrient limitation, in both haploid and diploid cells. This inhibition by Sut1 is independent of its function in sterol uptake. Sut1 downregulates the expression of GAT2, HAP4, MGA1, MSN4, NCE102, PRR2, RHO3, and RHO5. Several of these Sut1 targets (GAT2, HAP4, MGA1, RHO3, and RHO5) are essential for filamentation in haploids and/or diploids. Furthermore, the expression of the Sut1 target genes, with the exception of MGA1, is induced during filamentous growth. We also show that SUT1 expression is autoregulated and inhibited by Ste12, a key transcriptional regulator of filamentation. We propose that Sut1 partially represses the expression of GAT2, HAP4, MGA1, MSN4, NCE102, PRR2, RHO3, and RHO5 when nutrients are plentiful. Filamentation-inducing conditions relieve this repression by Sut1, and the increased expression of Sut1 targets triggers filamentous growth.The project was supported by Deutsche Forschungsgemeinschaft grant HO 2098/

Reproducible Molecularly Imprinted Piezoelectric Sensor for Accurate and Sensitive Detection of Ractopamine in Swine and Feed Products

This paper describes the development of a reproducible molecularly imprinted piezoelectric sensor for the accurate and sensitive detection of ractopamine (RAC) in swine and feed products. The synthesized molecularly imprinted polymer (MIP) was directly immobilized on the surface of a quartz crystal microbalance (QCM) Au chip as the recognition element. The experimental parameters in the fabrication, measurement and regeneration process were evaluated in detail to produce an MIP-based piezoelectric sensor with high sensing capability. The developed piezoelectric sensor was verified to perform favorably in the RAC analysis of swine and feed products, with acceptable accuracy (recovery: 75.9–93.3%), precision [relative standard deviation (n = 3): 2.3–6.4%], and sensitivity [limit of detection: 0.46 ng g−1 (swine) and 0.38 ng g−1 (feed)]. This portable MIP-based chip for the piezoelectric sensing of RAC could be reused for at least 30 cycles and easily stored for a long time. These results demonstrated that the developed MIP-based piezoelectric sensor presents an accurate, sensitive and cost-effective method for the quantitative detection of RAC in complex samples. This research offers a promising strategy for the development of novel effective devices used for use in food safety analysis

Cryptosporidium parvum gp40/15 Is Associated with the Parasitophorous Vacuole Membrane and Is a Potential Vaccine Target

Cryptosporidium parvum is a zoonotic intracellular protozoan responsible for the diarrheal illness cryptosporidiosis in humans and animals. Although a number of zoite surface proteins are known to be expressed during, and believed to be involved in, attachment and invasion of host cells, the molecular mechanisms by which C. parvum invades the host epithelial cells are not well understood. In the present study, we investigated the gene expression patterns, protein localization in developmental stages in culture, and in vitro neutralization characteristics of Cpgp40/15 and Cpgp40. Indirect immunofluorescence assay showed that Cpgp40/15 is associated with the parasitophorous vacuole membrane (PVM) during intracellular development. Both anti-gp40/15 and anti-gp40 antibodies demonstrated the ability to neutralize C. parvum infection in vitro. Further studies are needed to fully understand the specific role and functional mechanism of Cpgp40/15 (or gp40/15 complex) in the invasion of the host or in the PVM and to determine the feasibility of gp40/15 as a vaccine candidate for cryptosporidiosis in vivo

Experiment and Forward Modeling Analysis of Microgravity Detection of Urban Underground Space

With the rapid development of national cities, the demand for urban underground space exploration development and utilization has increased. Due to the interference factors in human activities areas, traditional geophysical methods can't obtain true and accurate detection data. The microgravity method is relatively less affected by interference factors. The interference from urban buildings and human activities can be eliminated by the method of model forward correction, so as to obtain high-precision gravity collection data, and then the spatial location information of tunnel, goaf, cavity, collapse area and pipe gallery in urban underground space can be obtained through effective inversion method. In this paper, through experimental detection and analysis of the theoretically affected factors in the urban detection carried out by the ground mobile high-precision gravity measuring instrument, combined with the forward model correction research, the microgravity method shows good effect in the detection of urban underground space

Infrared Photodissociation Spectroscopic and Theoretical Study of Homoleptic Dinuclear Chromium Carbonyl Cluster Cations with a Linear Bridging Carbonyl Group

Infrared spectra of mass-selected homoleptic dinuclear chromium carbonyl cluster cations Cr₂(CO)_<i>n</i>⁺ with <i>n</i> = 7–9 are measured via infrared photodissociation spectroscopy in the carbonyl stretching frequency region in the gas phase. The structures are established by comparison of the experimental spectra with the simulated spectra derived from density functional calculations. The Cr₂(CO)_<i>n</i>⁺ cluster cations are characterized to have the (OC)₅Cr–C–O–Cr­(CO)_<i>n</i>−6⁺ structures with a linear bridging carbonyl group bonded to one chromium atom through its carbon atom and to the other chromium atom through its oxygen atom. The cluster cations all have a sextet ground state with the positive charge and the unpaired electrons located on the Cr­(CO)_<i>n</i>−6 moiety. The formation of the linear bridging structures without Cr–Cr bonding can be rationalized that chromium forms strong Cr–CO bonds but weak Cr–Cr bonds

A research on urban disaster resilience assessment system for rainstorm and flood disasters: A case study of Beijing.

Under the background of global climate change, rainstorm and flood disasters have become the most serious cataclysm. Under the circumstances of an increasingly severe risk situation, it is necessary to enhance urban disaster resilience. Based on the disaster resilience process of prevention, absorption, and enhancement, and considering the safety factors such as personnel, facility, environment and management, this paper forms a dual dimension of the urban disaster resilience assessment model covering the key elements of urban disaster response and the core capacity of urban disaster recovery. Furthermore, if taking into account the characteristics of rainstorm and flood disasters, the paper screens the key indicators to build up an assessment index system of an urban rainstorm and flood disaster. The practical application was implemented in Beijing to have an assessment of the ability to recover from rainstorm and flood disasters in all districts of Beijing. And then, some pertinent suggestions for enhancing the resilience of Beijing to rainstorm and flood disasters were proposed

Infrared Photodissociation Spectroscopy of Mass Selected Homoleptic Copper Carbonyl Cluster Cations in the Gas Phase

Infrared spectra of mass-selected homoleptic copper carbonyl cluster cations including dinuclear Cu₂(CO)₆⁺ and Cu₂(CO)₇⁺, trinuclear Cu₃(CO)₇⁺, Cu₃(CO)₈⁺, and Cu₃(CO)₉⁺, and tetranuclear Cu₄(CO)₈⁺ are measured via infrared photodissociation spectroscopy in the carbonyl stretching frequency region. The structures are established by comparison of the experimental spectra with simulated spectra derived from density functional calculations. The Cu₂(CO)₆⁺ cation is characterized to have an unbridged <i>D</i>_3<i>d</i> structure with a Cu–Cu half bond. The Cu₂(CO)₇⁺ cation is determined to be a weakly bound complex involving a Cu₂(CO)₆⁺ core ion. The trinuclear Cu₃(CO)₇⁺ and Cu₃(CO)₈⁺ cluster cations are determined to have triangle Cu₃ core structures with <i>C</i>₂ symmetry involving two Cu­(CO)₃ groups and one Cu­(CO)_<i>x</i> group (<i>x</i> = 1 or 2). In contrast, the trinuclear Cu₃(CO)₉⁺ cluster cation is determined to have an open chain-like (OC)₃Cu–Cu­(CO)₃–Cu­(CO)₃ structure. The tetranuclear Cu₄(CO)₈⁺ cluster cation is characterized to have a tetrahedral Cu₄⁺ core structure with all carbonyl groups terminally bonded