Microbiology Blog: The weblog for microbiologists
Microbiology news and views to help the busy scientist keep up-to-date on current research, forthcoming conferences, hot research topics, high impact publications, and much more.
Function of Cellular Prion Protein
from Takashi Onodera, Katsuaki Sugiura, Shigeru Matsuda and Akikazu Sakudo writing in Prions: Current Progress in Advanced Research:
Although much is known about the effect of PrPSc in prion diseases, the normal function of PrPC is poorly understood. PrPC may act as an antiapoptotic agent by blocking some of the internal environmental factors that initiate apoptosis. PrP-knockout methods provide powerful hints on the neuroprotective function of PrPC. Using PrPC-knockout cell lines, the inhibition of apoptosis through STI1 is mediated by PrPC-dependent SOD activation. Recently several reports show that PrPC participate in trans-membrane signaling process associated with hematopoietic stem cell replication and neuronal differentiation. Besides PrP-knockout exhibited wide spread alterations of oscillatory activity in the olfactory bulb as well as altered paired-pulse plasticity at the dendrodendric synapse. Both the behavioral and electro-physiological phenotypes could be rescued by neuronal PrPC expression. Neuprotein Shadoo (Sho), similarly to PrPC, can prevent neuronal cell death induced by the expression of PrP△HD mutants, an artificial PrP mutant devoid of internal hydrophobic domain. Sho can efficiently protect cells against exito-toxin-induced cell death by glutamates. Sho and PrP seem to be dependent on similar domains, in particular N-terminal (N) and their internal hydrophobic domain. Sho△N and Sho△HD displayed a reduced stress-protective activity but are complex glycosylated and attached to outer leaflet of the plasma membrane via GPI anchor indicating that impaired activity is not due to incorrect cellular trafficking. In Shadoo over-expressed mice showed large amyloid plaques not seen in wild-type mice. However Shadoo is not a major modulator of PrPSc accumulation and scrapie pathogenesis. Sho and PrP share a stress-protective activity. The ability to adopt a toxic conformation of PrPSc seems to be specific for PrP.
Further reading: Prions: Current Progress in Advanced Research
Fungi in Cryosphere
from Tamotsu Hoshino, Nan Xiao, Yuka Yajima and Oleg B. Tkachenko writing in Cold-Adapted Microorganisms:
Cold-adapted fungi are widely distributed in the cryopsphere where biosphere is constantly or seasonally covered with snow and/or ice. Fungi normally have different cells in their lifecycle; therefore, thermal dependence of fungal lifecycle stages is completely different from that of bacteria. We showed examples from fungi that the concept of "psychrophile" by Moria in 1975 was not applicable and propose a new term "cryophilic fungi" for those that spend a certain life stage or whole life cycle (sexual and/or asexual reproductions) in cryosphere. Several groups of fungi associated with snow and/or ice, i.e., cryophilc fungi, are illustrated in terms of their ecology, and their ecophysiological adaptation mechanisms to freezing stress are reviewed, here.
Further reading: Cold-Adapted Microorganisms
Omics in Soil Science
This volume presents the state-of-the-art of omic applications in soil science, a field that is advancing rapidly on many fronts. Distinguished authors describe the application of metagenomics, metatranscriptomics and proteomics to soil science. In particular the book covers the current and emerging omics techniques and the contribution of these approaches to a better assessment of soil functionality. The authors also explore the specific problems encountered in the application of various omics technologies to soil science and the future research requirements necessary to overcome the current limitations in this area. Topics covered include soil functional genomics, soil metagenomics, soil microbial ecology, soil metatranscriptomics, soil proteomics, soil volatilomics and soil proteogenomics. Omics techniques are also discussed in comparison with classical techniques. This book is both a practical guide and a recommended reference volume for all soil scientists read more ...
 | Edited by: Paolo Nannipieri, Giacomo Pietramellara and Giancarlo Renella read more ...ISBN: 978-1-908230-32-4 Publisher: Caister Academic Press Publication Date: March 2014 Cover: hardback |
Future Prospect
from Takashi Onodera and Katsuaki Sugiura writing in Prions: Current Progress in Advanced Research:
Results in Netherlands show that classic scrapie control can be obtained at the national scale without a loss of genetic polymorphism from any of sheep breed. No classical scrapie strain thus far has escaped ARR-associated resistance. Ongoing studies show that atypical scrapie strain also was controlled by ARR-associated resistance. In line with this expectation, the breeding program proved successful in Dutch flock in 2010. When considering the rapid outbreak control as observed in Netherland study, the use of resistant rams seems sufficient and can be recommended as a control strategy in scrapie-affected countries. The origin of atypical BSE cases is currently unknown. As with classical BSE, exposure of these animals to feed contaminated with low titers of TSE agent cannot be excluded, although other origins for these TSE forms cannot be discarded. In particular, the unusually old ages of all H-BSE and L-BSE identified cases and their apparent low-prevalence in the population could suggest that these atypical BSE forms are arising spontaneously. PMCA needs to be highly standardized and robust in terms of a consistent and objectively quantifiable PrPres amplification if to be used for quantification of the proteinaceous seeding activity of prions. There is a direct quantitative correspondence between the seeding and infectious activities of 263K scrapie prions measured by RT-QuIC and bioassay. The methodological, conceptual and practical results described in the report of 263K scrapie prions should be validated for the most human TSE agents. Although scrapie has been known for decades, relatively little attention has been paid to it as a natural disease of sheep and goats mainly because the economical impact has been relatively small compared to other diseases in sheep. The occurrence of bovine spongiform encephalopathy (BSE) provide a new impetus to research into the transmissible spongiform encephalopathies (TSE). Not only was the economical impact of BSE much greater than that of scrapie, the link with variant Creutzfeldt-Jakob disease (vCJD) in humans also gave rise to serious concerns regarding food safety.
Further reading: Prions: Current Progress in Advanced Research
Heat Shock Responce in Psychrophilic Microorganisms
from Seiji Yamauchi, Shinsuke Fukuda and Hidenori Hayashi writing in Cold-Adapted Microorganisms:
Psychrophilic microorganisms can optimally grow at temperatures below 15°C. In these microorganisms, heat stress occurs at relatively low temperatures in comparison with that in mesophilic microorganisms. The majority of psychrophilic microorganisms possess genes encoding a complete set of heat shock proteins (Hsps). Therefore, psychrophilic microorganisms respond to heat stress by producing Hsps like other microorganisms; however, they need a specific system to enable the expression and function of Hsps at relatively low temperatures. In this chapter, we summarize the heat shock response of psychrophilic microorganisms, focusing on how this response starts working at relatively low temperatures and what the features of psychrophilic Hsps are.
Further reading: Cold-Adapted Microorganisms
Homogenous Fluorescent Chemistries for Real-time PCR
from Martin A. Lee, David J. Squirrell, Dario L. Leslie and Tom Brown writing in Real-Time PCR: Advanced Technologies and Applications:
The development of fluorescent methods for the closed tube polymerase chain reaction has greatly simplified the process of quantification. Current approaches use fluorescent probes that interact with the amplification products during the PCR to allow kinetic measurements of product accumulation. These probe methods include generic approaches to DNA quantification such as fluorescent DNA binding dyes. There are also a number of strand-specific probes that use the phenomenon of Fluorescent Energy Transfer. In this chapter we describe these methods in detail, outline the principles of each process, and describe published examples. This text has been written to provide an impartial overview of the utility of different assays and to show how they may be used on various commercially available thermal cyclers.
Further reading: Real-Time PCR: Advanced Technologies and Applications