Quality Control of Fungal and Viral Biocontrol Agents - Assurance of Product Performance

An essential feature of the production of all microbial control agents is an effective quality control system. Well-defined product specifications with accompanying quality control procedures help to maximize product performance, ensure product safety, standardize manufacturing costs and reduce the risks of supply failure, thus building user confidence. A production system that does not have a quality control system is one whose output is uncontrolled and a lack of thorough quality feedback can result in batches of product with variable concentrations of active agent. This results in products with variable performance leading to control failures by users and serious loss of user confidence. Strict quality control procedures are not only essential for product consistency, but also for safety. Where quality control is inadequate, microbial contamination of the final product is inevitable. In most of such cases this will merely lead to a loss of efficacy due to dilution of the active ingredient by competing microorganisms, but also the potential of producing human pathogens must be ruled out. Recognition of contaminants and quantification of the degree of contamination are therefore important in determining any possible risk to human health. Many low technology production systems in use around the world have minimal or no quality control procedures. This is unacceptable and can damage the reputation of microbial control in addition to possibly posing health risks to those that produce or are exposed to the product. Two case studies from developing countries, are used to illustrate how the lack of quality control procedures can lead to the production of low viability, highly contaminated products with low or negligible concentrations of the active ingredient. However, it is also demonstrated that low technology production systems in developing countries can produce high quality products, provided appropriate quality control procedures are firmly implemented. It must be recognized that quality control procedures can be more complex and technologically demanding than the production procedures themselves, but it is largely on the effectiveness of these control procedures that the long-term acceptability of fungal and viral products depends. This paper details the quality control procedures considered necessary in the mass production of fungi and viruses for use as biocontrol agents, and attempts to suggest reasonable standards that can be achieved by all producers.     

Establishment of laboratory quality control indicators for NAT on blood donors' samples

In order to establish and screen nucleic acid test (NAT) quality control indicators for blood donor samples, C_T value of each test item were detected by NAT, internal and external quality controls, the number of unsuccessful mixed samples, the split positive rate, the rate of detection efficiency, and the equipment failure rate were collected. The "instant method" is used to establish the Levey-Jennings quality control chart, the mixed test positive rate, the rate of unqualified sample. Possion distribution is used to establish the quality control chart, and it is easily to operate and monitor NAT effectively. The results displayed that quality control charts were established, including unqualified sample Possion distribution quality control chart, the rate of equipment failure quality control chart, the failure rate of reagent batch and inefficient quality control chart, test result positive of Possion distribution quality control chart, quality control charts of NAT positive Possion distribution probability, the rate of split positive quality control charts, quality control charts of unsuccessful mixed samples, quality control chart of reagents effective rate, internal quality control chart, correctness, and NAT qualitative quality control chart. The study established quality control indicators throughout the whole NAT process, which were able to effectively improve NAT quality control and the efficacy of laboratory management.     

On Quality Control Measures in Genome-Wide Association Studies: A Test to Assess the Genotyping Quality of Individual Probands in Family-Based Association Studies and an Application to the HapMap Data

Allele transmissions in pedigrees provide a natural way of evaluating the genotyping quality of a particular proband in a family-based, genome-wide association study. We propose a transmission test that is based on this feature and that can be used for quality control filtering of genome-wide genotype data for individual probands. The test has one degree of freedom and assesses the average genotyping error rate of the genotyped SNPs for a particular proband. As we show in simulation studies, the test is sufficiently powerful to identify probands with an unreliable genotyping quality that cannot be detected with standard quality control filters. This feature of the test is further exemplified by an application to the third release of the HapMap data. The test is ideally suited as the final layer of quality control filters in the cleaning process of genome-wide association studies. It identifies probands with insufficient genotyping quality that were not removed by standard quality control filtering.     

Proofreading and spellchecking: a two-tier strategy for pre-mRNA splicing quality control

Multi-tier strategies exist in many biochemical processes to ensure a maximal fidelity of the reactions. In this review, we focus on the two-tier quality control strategy that ensures the quality of the products of the pre-mRNA splicing reactions catalyzed by the spliceosome. The first step in the quality control process relies on kinetic proofreading mechanisms that are internal to the spliceosome and that are performed by ATP-dependent RNA helicases. The second quality control step, spellchecking, involves recognition of unspliced pre-mRNAs or aberrantly spliced mRNAs that have escaped the first proofreading mechanisms, and subsequent degradation of these molecules by degradative enzymes in the nucleus or in the cytoplasm. This two-tier quality control strategy highlights a need for high fidelity and a requirement for degradative activities that eliminate defective molecules. The presence of multiple quality control activities during splicing underscores the importance of this process in the expression of genetic information.     

Restricted access: spatial sequestration of damaged proteins during stress and aging

The accumulation of damaged and aggregated proteins is a hallmark of aging and increased proteotoxic stress. To limit the toxicity of damaged and aggregated proteins and to ensure that the damage is not inherited by succeeding cell generations, a system of spatial quality control operates to sequester damaged/aggregated proteins into inclusions at specific protective sites. Such spatial sequestration and asymmetric segregation of damaged proteins have emerged as key processes required for cellular rejuvenation. In this review, we summarize findings on the nature of the different quality control sites identified in yeast, on genetic determinants required for spatial quality control, and on how aggregates are recognized depending on the stress generating them. We also briefly compare the yeast system to spatial quality control in other organisms. The data accumulated demonstrate that spatial quality control involves factors beyond the canonical quality control factors, such as chaperones and proteases, and opens up new venues in approaching how proteotoxicity might be mitigated, or delayed, upon aging.     

CHIP deficiency decreases longevity, with accelerated aging phenotypes accompanied by altered protein quality control

During the course of biological aging, there is a gradual accumulation of damaged proteins and a concomitant functional decline in the protein degradation system. Protein quality control is normally ensured by the coordinated actions of molecular chaperones and the protein degradation system that collectively help to maintain protein homeostasis. The carboxyl terminus of Hsp70-interacting protein (CHIP), a ubiquitin ligase/cochaperone, participates in protein quality control by targeting a broad range of chaperone substrates for proteasome degradation via the ubiquitin-proteasome system, demonstrating a broad involvement of CHIP in maintaining cytoplasmic protein quality control. In the present study, we have investigated the influence that protein quality control exerts on the aging process by using CHIP-/- mice. CHIP deficiency in mice leads to a markedly reduced life span, along with accelerated age-related pathophysiological phenotypes. These features were accompanied by indications of accelerated cellular senescence and increased indices of oxidative stress. In addition, CHIP-/- mice exhibit a deregulation of protein quality control, as indicated by elevated levels of toxic oligomer proteins and a decline in proteasome activity. Taken together, these data reveal that impaired protein quality control contributes to cellular senescence and implicates CHIP-dependent quality control mechanisms in the regulation of mammalian longevity in vivo.     

城市生态观测:质量控制对象、体系和规范编制

城市生态系统长期观测是开展城市生态安全评价和制定人居环境健康管理政策的基础。为了确保城市生态观测数据的准确性和科学性,通过辨识城市生态观测质量控制的概念,基于"人机料法环"理论构建了城市生态观测质量控制体系,结合城市生态观测质量控制相关规范的编制与实施现状,探讨了城市生态观测质量控制规范的编制技术。结果表明：（1）城市生态观测质量控制是面向城市生态观测内容（要素、空间格局、功能、服务）,为保证生态观测全过程质量要求、提高生态观测结果的准确性而实施的质量控制活动和措施。（2）城市生态观测质量控制体系可从对象和过程这两个维度进行界定：对象维度方面,包括"人"-人员、"机"-仪器设备、"料"-数据、"法"-文件和"环"-观测过程5个方面;过程维度方面,涵盖城市生态观测全过程,包括城市生态观测前期准备工作、观测过程中以及观测后的数据录入、审核与评价等环节的质量控制措施。（3）我国已发布的生态观测相关技术标准中,发布的时间越晚,质量控制内容越完整,目前生态观测相关标准共102则,仅38则明确提出了质量控制具体要求。（4）《城市生态观测质量控制规范》编制需包含质量体系和质量控制措施两项技术内容,主要包括前引、正文和附录三个章节,对生态观测全过程质量保证和质量控制技术进行规定。     

Quality control systems for aberrant mRNAs induced by aberrant translation elongation and termination

RNA processing is an essential gene expression step and plays a crucial role to achieve diversity of gene products in eukaryotes. Various aberrant mRNAs transiently produced during RNA processing reactions are recognized and eliminated by specific quality control systems. It has been demonstrated that these mRNA quality control systems stimulate the degradation of aberrant mRNA to prevent the potentially harmful products derived from aberrant mRNAs. Recent studies on quality control systems induced by abnormal translation elongation and termination have revealed that both aberrant mRNAs and proteins are subjected to rapid degradation. In NonStop Decay (NSD) quality control system, a poly(A) tail of nonstop mRNA is translated and the synthesis of poly-lysine sequence results in translation arrest followed by co-translational degradation of aberrant nonstop protein. In No-Go Decay (NGD) quality control system, the specific amino acid sequences of the nascent polypeptide induce ribosome stalling, and the arrest products are ubiquitinated and rapidly degraded by the proteasome. In Nonfunctional rRNA Decay (NRD) quality control system, aberrant ribosomes composed of nonfunctional ribosomal RNAs are also eliminated when aberrant translation elongation complexes are formed on mRNA. I describe recent progresses on the mechanisms of quality control systems and the relationships between quality control systems. This article is part of a Special issue entitled: RNA Decay mechanisms.     

Folding and quality control of the VHL tumor suppressor proceed through distinct chaperone pathways

The mechanisms by which molecular chaperones assist quality control of cytosolic proteins are poorly understood. Analysis of the chaperone requirements for degradation of misfolded variants of a cytosolic protein, the VHL tumor suppressor, reveals that distinct chaperone pathways mediate its folding and quality control. While both folding and degradation of VHL require Hsp70, the chaperonin TRiC is essential for folding but is dispensable for degradation. Conversely, the chaperone Hsp90 neither participates in VHL folding nor is required to maintain misfolded VHL solubility but is essential for its degradation. The cochaperone HOP/Sti1p also participates in VHL quality control and may direct the triage decision by bridging the Hsp70-Hsp90 interaction. Our finding that a distinct chaperone complex is uniquely required for quality control provides evidence for active and specific chaperone participation in triage decisions and suggests that a hierarchy of chaperone interactions can control the alternate fates of a cytosolic protein.     

Lipid-mediated, reversible misfolding of a sterol-sensing domain protein

Cellular quality control requires recognition of common features of misfolding, and so is not typically associated with the specific targeting of individual proteins. However, physiologically regulated degradation of yeast HMG-CoA reductase (Hmg2p) occurs by the HRD endoplasmic reticulum quality control pathway, implying that Hmg2p undergoes a regulated transition to a quality control substrate in response to a sterol pathway molecule. Using in vitro structural assays, we now show that the pathway derivative farnesol causes Hmg2p to undergo a change to a less folded structure. The effect is reversible, biologically relevant by numerous criteria, highly specific for farnesol structure, and requires an intact Hmg2p sterol-sensing domain. This represents a distinct lipid-sensing function for this highly conserved motif that suggests novel approaches to cholesterol management. More generally, our observation of reversible small-molecule-mediated misfolding may herald numerous examples of regulated quality control to be discovered in biology or applied in the clinic.     

Quality meets quantity - quality control, data standards and repositories

In recent years, standardization and quality control have become important key points in industry, e.g. in drug discovery and for developing medical products. Is quality control in academic Proteomics a minor problem nowadays, where standard data formats and public repositories for data sharing exist? In this article, it is discussed how standard formats and repositories already support the documentation of quality control criteria in protein identification and quantification, and what has to be improved in the future: It is stated that the Proteomics community (represented by a group like the Proteomics Standards Initiative) will have to define a minimum document regarding quality control and to extend existing standards with additional quality control criteria enabling a substantial and standardized quality control process.     

Needless Retesting of Quality-Assured, Commercially Prepared Culture Media

Current revival of interest in quality control of bacteriological culture media prompted this laboratory to develop and implement a system of quality control testing of media purchased from commercial manufacturers. During 8 months we tested more than 900 lots of 46 different media representing 350,000 units of culture media purchased from two major and one minor supplier(s). Only 17 lots were found to be unsatisfactory. This experience raised a question about the real necessity for extensive retesting by users of commercially prepared, quality-assured media. It is suggested that primary responsibility for quality control be placed on the relatively few manufacturer-vendors rather than on the multiple purchaser-users, who may not possess either the expertise or the resources for quality control programs.     

综合性介入导管室的护理质量控制效果与体会

目的:探讨综合性介入导管室的护理质量控制效果并总结其体会。方法:随机选择我院不同科室的50名介入医生,通过自行设计的介入医生满意度调查表评估和比较其对综合性介入导管室和专科介入导管室的护理工作质量的满意度。结果:介入医生对综合性介入导管室的护理质量控制满意度显著优于专科介入导管室(P0.05)。结论:综合性介入导管室通过护理质量控制提高了介入医生的满意度,规范了工作程序,提高了护理质量,使我院导管室的工作更加正规化。     

认知护理干预在肝癌患者术后恢复中具有显著的疗效

为探讨认知护理干预对肝癌患者术后恢复的影响,本研究选取接受肝癌手术患者150例为观察对象,其中接受认知护理干预的患者84例,为观察组,接受普通护理的患者66例,为对照组。观察患者的疾病不确定感、疼痛程度、焦虑与抑郁(SAS与SDS)、生活质量和睡眠质量,评价认知干预对患者的影响。研究发现两组患者护理前疾病不确定感、SAS和SDS评分、睡眠质量和生活质量均无显著差异;护理后,观察组的疾病不确定感、SAS和SDS评分均极显著低于对照组(p<0.01),而睡眠质量和生活质量均显著高于对照组(p<0.01),观察组中度疼痛和重度疼痛患者明显少于对照组。研究表明认知护理干预有助于肝癌患者术后的恢复。     

检验全流程数字化管理及质量控制体系的构建

通过对检验工作各环节流程、质控情况的分析,制定了新的检验业务管理及质量控制流程,并利用数字化技术对流程各环节进行系统实现。检验全流程数字化管理及质量控制体系的构建,有效提高了检验工作的效率与质量安全,进一步促进了医院医疗质量管理水平的提高。     

Autophagy machinery promotes the chaperone-mediated formation and compartmentalization of protein aggregates during appressorium development by the rice blast fungus

The chaperone-mediated sequestration of misfolded proteins into specialized quality control compartments represents an important strategy for maintaining protein homeostasis in response to stress. However, precisely how this process is controlled in time and subcellular space and integrated with the cell''s protein refolding and degradation pathways remains unclear. We set out to understand how aggregated proteins are managed during infection-related development by a globally devastating plant pathogenic fungus and to determine how impaired protein quality control impacts cellular differentiation and pathogenesis in this system. Here we show that in the absence of Hsp104 disaggregase activity, aggregated proteins are spatially sequestered into quality control compartments within conidia, but not within terminally differentiated infection cells, and thus spatial protein quality control is cell type–dependent. We demonstrate that impaired aggregate resolution results in a short-term developmental penalty but has no significant impact upon appressorium function. Finally, we show that, somewhat unexpectedly, the autophagy machinery is necessary for the normal formation and compartmentalization of protein aggregates. Taken together, our findings provide important new insight into spatial protein quality control during the process of terminal cellular differentiation by a globally important model eukaryote and reveal a new level of interplay between major proteostasis pathways.     

In vivo action of the HRD ubiquitin ligase complex: mechanisms of endoplasmic reticulum quality control and sterol regulation

Ubiquitination is used to target both normal proteins for specific regulated degradation and misfolded proteins for purposes of quality control destruction. Ubiquitin ligases, or E3 proteins, promote ubiquitination by effecting the specific transfer of ubiquitin from the correct ubiquitin-conjugating enzyme, or E2 protein, to the target substrate. Substrate specificity is usually determined by specific sequence determinants, or degrons, in the target substrate that are recognized by the ubiquitin ligase. In quality control, however, a potentially vast collection of proteins with characteristic hallmarks of misfolding or misassembly are targeted with high specificity despite the lack of any sequence similarity between substrates. In order to understand the mechanisms of quality control ubiquitination, we have focused our attention on the first characterized quality control ubiquitin ligase, the HRD complex, which is responsible for the endoplasmic reticulum (ER)-associated degradation (ERAD) of numerous ER-resident proteins. Using an in vivo cross-linking assay, we directly examined the association of the separate HRD complex components with various ERAD substrates. We have discovered that the HRD ubiquitin ligase complex associates with both ERAD substrates and stable proteins, but only mediates ubiquitin-conjugating enzyme association with ERAD substrates. Our studies with the sterol pathway-regulated ERAD substrate Hmg2p, an isozyme of the yeast cholesterol biosynthetic enzyme HMG-coenzyme A reductase (HMGR), indicated that the HRD complex discerns between a degradation-competent "misfolded" state and a stable, tightly folded state. Thus, it appears that the physiologically regulated, HRD-dependent degradation of HMGR is effected by a programmed structural transition from a stable protein to a quality control substrate.     

Peptide identification quality control

Identification of large proteomics data sets is routinely performed using sophisticated software tools called search engines. Yet despite the importance of the identification process, its configuration and execution is often performed according to established lab habits, and is mostly unsupervised by detailed quality control. In order to establish easily obtainable quality control criteria that can be broadly applied to the identification process, we here introduce several simple quality control methods. An unbiased quality control of identification parameters will be conducted using target/decoy searches providing significant improvement over identification standards. MASCOT identifications were for instance increased by 13% at a constant level of confidence. The target/decoy approach can however not be universally applied. We therefore also quality control the application of this strategy itself, providing useful and intuitive metrics for evaluating the precision and robustness of the obtained false discovery rate.     

Data quality assessment of ungated flow cytometry data in high throughput experiments.

BACKGROUND: The recent development of semiautomated techniques for staining and analyzing flow cytometry samples has presented new challenges. Quality control and quality assessment are critical when developing new high throughput technologies and their associated information services. Our experience suggests that significant bottlenecks remain in the development of high throughput flow cytometry methods for data analysis and display. Especially, data quality control and quality assessment are crucial steps in processing and analyzing high throughput flow cytometry data. METHODS: We propose a variety of graphical exploratory data analytic tools for exploring ungated flow cytometry data. We have implemented a number of specialized functions and methods in the Bioconductor package rflowcyt. We demonstrate the use of these approaches by investigating two independent sets of high throughput flow cytometry data. RESULTS: We found that graphical representations can reveal substantial nonbiological differences in samples. Empirical Cumulative Distribution Function and summary scatterplots were especially useful in the rapid identification of problems not identified by manual review. CONCLUSIONS: Graphical exploratory data analytic tools are quick and useful means of assessing data quality. We propose that the described visualizations should be used as quality assessment tools and where possible, be used for quality control.     

Immunocytochemical staining of effusions; an external quality control study in The Netherlands

Immunocytochemical staining of effusions; an external quality control study in The Netherlands
In The Netherlands an external quality control study of immunocytochemical (IC) staining of effusions was initiated, consisting of three test rounds. The 12 participating laboratories received samples of malignant effusions (runs 1, 2 and 3), and five unstained control specimens prepared from the same material in runs 2 and 3. The laboratories used their own protocols to prepare and stain the samples ('in‐house' specimens). Two persons viewed and scored the slides following preset criteria concerning number and morphology of diagnostic cells, background staining and staining specificity. Better scoring results were found for control specimens, compared with 'in‐house' specimens, primarily caused by cell loss in the latter. This finding underlines the view that high quality IC needs well organized processing and staining procedures, and warrants external quality control systems.