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Regulation of DNA-templated processes such as gene transcription and DNA repair depend on the interaction of a wide range of proteins with the nucleosome, the fundamental building block of chromatin. Both solution and solid-state NMR spectroscopy have become an attractive approach to study the dynamics and interactions of nucleosomes, despite their high molecular weight of ∼200 kDa. For solid-state NMR (ssNMR) studies, dilute solutions of nucleosomes are converted to a dense phase by sedimentation or precipitation. Since nucleosomes are known to self-associate, these dense phases may induce extensive interactions between nucleosomes, which could interfere with protein-binding studies. Here, we characterized the packing of nucleosomes in the dense phase created by sedimentation using NMR and small-angle X-ray scattering (SAXS) experiments. We found that nucleosome sediments are gels with variable degrees of solidity, have nucleosome concentration close to that found in crystals, and are stable for weeks under high-speed magic angle spinning (MAS). Furthermore, SAXS data recorded on recovered sediments indicate that there is no pronounced long-range ordering of nucleosomes in the sediment. Finally, we show that the sedimentation approach can also be used to study low-affinity protein interactions with the nucleosome. Together, our results give new insights into the sample characteristics of nucleosome sediments for ssNMR studies and illustrate the broad applicability of sedimentation-based NMR studies.

Feed transition of Steindachneridion scripta larvae was investigated using seven treatments in which the reference diet, Artemia spp. nauplii, was totally substituted for a 56% crude protein artificial diet in two-day intervals. Initially, all treatments were fed with Artemia spp. nauplii and, subsequently, during the transition period, feed was equally composed by Artemia sp. nauplii and artificial diet. Everyday, one of the treatments began the feed transition, which was implemented between the second and the eighth days of culturing. Two treatments were used as control: one exclusively fed Artemia spp. nauplii and another only with artificial diet. Total weight, total length, and survival rate were not influenced by the day in which feed transition was implemented (P>0.05), and their mean values (± SD) were 31.1±25.0mg, 13.3±1.5mm and 58.8±12.0%, respectively. This suggests that Steindachneridion scripta larvae adapted well the transition to artificial diet.A transição alimentar de larvas de Steindachneridion scripta foi investigada utilizando-se sete tratamentos, nos quais a dieta básica, composta por náuplios de Artemia spp., foi integralmente substituída, em intervalo de dois dias, por uma dieta artificial contendo 56% de proteína bruta. Inicialmente, todos os tratamentos receberam náuplios de Artemia spp. No período de transição alimentar, metade da alimentação foi formada por náuplios de Artemia spp. e metade por dieta artificial. A cada dia, um dos tratamentos entrou na fase de transição, que foi implementada entre o segundo e o oitavo dia de cultivo. Utilizaram-se dois tratamentos como controle; em um as larvas foram alimentadas, exclusivamente, com náuplios de Artemia spp. e em outro, somente, com dieta artificial. Peso total, comprimento total e sobrevivência não foram influenciados pelo dia de implantação da transição alimentar (P>0,05) e, apresentaram valores médios iguais a (± desvio padrão) 31,1±25,0mg, 13,3±1,5mm e 58,8±12,0%, respectivamente, sugerindo que as larvas Steindachneridion scripta aceitaram bem a transição alimentar para a dieta artificial.

Abstract Bioelectrical impedance analysis (BIA) is regarded as an important tool for evaluating the body composition of different animals in a rapid, non-destructive, and low-cost manner. A South American fish species, Steindachneridion scriptum, known as suruvi, was selected for study in this investigation. A protocol to produce fish with different body composition was used to allow BIA to adequately predict the body composition of suruvi. The fish were fed twice each day with two different diets; a low lipid diet (8.90%), and a high lipid diet (18.68%). These dietary differences allowed suruvi specimens with different body compositions to be produced. The BIA readings were determined using a Quantum X Bioelectrical Body Composition Analyzer. Two readings (dorsal and ventral) were obtained for each fish. After BIA readings were obtained, the proximate composition of the fish bodies for each individual was determined. All of the study data were used to establish correlation equations between proximate analyses and BIA values. Strong correlations were found for S. scriptum. The highest correlations were obtained for the following pairs of quantities, using BIA data from dorsal readings: moisture and resistance in series (R2 = 0.87); protein and resistance in series (R2 = 0.87); and ash and reactance in parallel (R2 = 0.82). We conclude that BIA is an effective method in determining the body composition of S. scriptum without sacrificing the fish. However, to expand the use of this new technology it is important to define strict BIA protocols to guarantee accurate estimates.

Mechanisms of nucleic acid accumulation were likely critical to life's emergence in the ferruginous oceans of the early Earth. How exactly prebiotic geological settings accumulated nucleic acids from dilute aqueous solutions, is poorly understood. As a possible solution to this concentration problem, we simulated the conditions of prebiotic low-temperature alkaline hydrothermal vents in co-precipitation experiments to investigate the potential of ferruginous chemical gardens to accumulate nucleic acids via sorption. The injection of an alkaline solution into an artificial ferruginous solution under anoxic conditions (O 2  < 0.01% of present atmospheric levels) and at ambient temperatures, caused the precipitation of amakinite ("white rust"), which quickly converted to chloride-containing fougerite ("green rust"). RNA was only extractable from the ferruginous solution in the presence of a phosphate buffer, suggesting RNA in solution was bound to Fe 2+ ions. During chimney formation, this iron-bound RNA rapidly accumulated in the white and green rust chimney structure from the surrounding ferruginous solution at the fastest rates in the initial white rust phase and correspondingly slower rates in the following green rust phase. This represents a new mechanism for nucleic acid accumulation in the ferruginous oceans of the early Earth, in addition to wet-dry cycles and may have helped to concentrate RNA in a dilute prebiotic ocean., (© 2023 The Authors. Geobiology published by John Wiley & Sons Ltd.)

Alkaline vents (AVs) are hypothesized to have been a setting for the emergence of life, by creating strong gradients across inorganic membranes within chimney structures. In the past, three-dimensional chimney structures were formed under laboratory conditions; however, no in situ visualization or testing of the gradients was possible. We develop a quasi-two-dimensional microfluidic model of AVs that allows spatiotemporal visualization of mineral precipitation in low-volume experiments. Upon injection of an alkaline fluid into an acidic, iron-rich solution, we observe a diverse set of precipitation morphologies, mainly controlled by flow rate and ion concentration. Using microscope imaging and pH-dependent dyes, we show that finger-like precipitates can facilitate formation and maintenance of microscale pH gradients and accumulation of dispersed particles in confined geometries. Our findings establish a model to investigate the potential of gradients across a semipermeable boundary for early compartmentalization, accumulation, and chemical reactions at the origins of life.

Background: The impact of frailty on walking recovery after hip fracture has not been reported. We describe the prevalence of frailty approximately 3 months after hip fracture, and identify the impact of baseline frailty on ambulation recovery., Methods: Data from the Community Ambulation Project, that examined the effects of 2 multicomponent home exercise programs on 6-minute walk test in participants post hip fracture, were used to reconstruct the 5-item frailty phenotype. We detailed the prevalence of frailty by subgroup and assessed the comparability between frailty groups for the categorical variable of achieving 300 m in 6-minute walk test (community ambulation threshold), and the continuous variable of total distance in 6-minute walk test before and after 16 weeks of intervention., Results: Of the 210 participants, 9% were nonfrail, 59% were prefrail, and 32% were frail. The odds of a nonfrail participant achieving the 300-m threshold were 14.4 (95% CI: 2.4-87.6) times the odds of a frail participant, while a prefrail participant's odds were 6.1 (95% CI: 1.3-28.4) times after controlling for treatment group and baseline walking distance. The nonfrail participants had an increase of 92.1 m from baseline to 16 weeks, the prefrail had a 50.8 m increase, and the frail group had the smallest increase of 36.6 m (p < .001 for all)., Conclusions: Prefrailty and frailty were highly prevalent in this sample of community-dwelling survivors of a recent hip fracture. Gains in walking distance and attaining a level of community ambulation were affected significantly by the level of baseline frailty., (© The Author(s) 2021. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

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Neuroblastoma is an aggressive pediatric malignancy of the neural crest with suboptimal cure rates and a striking predilection for widespread metastases, underscoring the need to identify novel therapeutic vulnerabilities. We recently identified the RNA binding protein LIN28B as a driver in high-risk neuroblastoma and demonstrated it promotes oncogenic cell proliferation by coordinating a RAN-Aurora kinase A network. Here, we demonstrate that LIN28B influences another key hallmark of cancer, metastatic dissemination. Using a murine xenograft model of neuroblastoma dissemination, we show that LIN28B promotes metastasis. We demonstrate that this is in part due to the effects of LIN28B on self-renewal and migration, providing an understanding of how LIN28B shapes the metastatic phenotype. Our studies reveal that the let-7 family, which LIN28B inhibits, decreases self-renewal and migration. Next, we identify PDZ Binding Kinase (PBK) as a novel LIN28B target. PBK is a serine/threonine kinase that promotes the proliferation and self-renewal of neural stem cells and serves as an oncogenic driver in multiple aggressive malignancies. We demonstrate that PBK is both a novel direct target of let-7i and that MYCN regulates PBK expression, thus elucidating two oncogenic drivers that converge on PBK. Functionally, PBK promotes self-renewal and migration, phenocopying LIN28B. Taken together, our findings define a role for LIN28B in neuroblastoma metastasis and define the targetable kinase PBK as a potential novel vulnerability in metastatic neuroblastoma., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Importance: Individuals living with schizophrenia are affected by cardiometabolic, endocrine, and motor adverse effects of current antipsychotic medications. Lumateperone is a serotonin, dopamine, and glutamate modulator with the potential to treat schizophrenia with few adverse effects., Objective: To examine the efficacy and safety of lumateperone for the short-term treatment of schizophrenia., Design, Setting, and Participants: This randomized, double-blind, placebo-controlled, phase 3 clinical trial was conducted from November 13, 2014, to July 20, 2015, with data analyses performed from August 13 to September 15, 2015. Patients with schizophrenia who were aged 18 to 60 years and were experiencing an acute exacerbation of psychosis were enrolled from 12 clinical sites in the United States., Interventions: Patients were randomized 1:1:1 (150 patients in each arm) to receive lumateperone tosylate, 60 mg; lumateperone tosylate, 40 mg (equivalent to 42 or 28 mg, respectively, of the active moiety lumateperone); or placebo once daily for 4 weeks., Main Outcomes and Measures: The prespecified primary efficacy end point was mean change from baseline to day 28 in the Positive and Negative Syndrome Scale (PANSS) total score vs placebo. The key secondary efficacy measure was the Clinical Global Impression-Severity of Illness (CGI-S) score. The PANSS subscale scores, social function, safety, and tolerability were also assessed., Results: The study comprised 450 patients (mean [SD] age, 42.4 [10.2] years; 346 [77.1%] male; mean [SD] baseline PANSS score, 89.8 [10.3]; mean [SD] baseline CGI-S score, 4.8 [0.6]). In the prespecified modified intent-to-treat efficacy analysis (n = 435), 42 mg of lumateperone met the primary and key secondary efficacy objectives, demonstrating a statistically significant improvement vs placebo from baseline to day 28 on the PANSS total score (least-squares mean difference [LSMD], -4.2; 95% CI, -7.8 to -0.6; P = .02; effect size [ES], -0.3) and the CGI-S (LSMD, -0.3; 95% CI, -0.5 to -0.1; P = .003; ES, -0.4). For 28 mg of lumateperone, the LSMD from baseline to day 28 was -2.6 (95% CI, -6.2 to 1.1; P = .16; ES, -0.2) on the PANSS total score and -0.2 (95% CI, -0.5 to 0.0; P = .02; ES, -0.3) on the CGI-S. Both lumateperone doses were well tolerated without clinically significant treatment-emergent motor adverse effects or changes in cardiometabolic or endocrine factors vs placebo., Conclusions and Relevance: Lumateperone demonstrated efficacy for improving the symptoms of schizophrenia and had a favorable safety profile., Trial Registration: ClinicalTrials.gov identifier: NCT02282761.

Dopamine D 2 receptor occupancy (D 2 RO) is a key feature of all currently approved antipsychotic medications. However, antipsychotic efficacy associated with high D 2 RO is often limited by side effects such as motor disturbances and hyperprolactinemia. Lumateperone (ITI-007) is a first-in-class selective and simultaneous modulator of serotonin, dopamine and glutamate in development for the treatment of schizophrenia and other disorders. The primary objective of the present study was to determine D 2 RO at plasma steady state of 60 mg ITI-007, a dose that previously demonstrated antipsychotic efficacy in a controlled trial, administered orally open-label once daily in the morning for two weeks in patients with schizophrenia (N = 10) and after at least a two-week washout period from standard of care antipsychotics. D 2 RO was determined using positron emission tomography with 11 C-raclopride as the radiotracer. Mean peak dorsal striatal D 2 RO was 39% at 60 mg ITI-007 occurring 1 h post-dose. Lumateperone was well-tolerated with a favorable safety profile in this study. There were no clinically significant changes in vital signs, ECGs, or clinical chemistry laboratory values, including prolactin levels. There were no adverse event reports of akathisia or other extrapyramidal motor side effects; mean scores on motor function scales indicated no motor disturbances with lumateperone treatment. This level of occupancy is lower than most other antipsychotic drugs at their efficacious doses and likely contributes to the favorable safety and tolerability profile of lumateperone with reduced risk for movement disorders and hyperprolactinemia. If approved, lumateperone may provide a new and safe treatment option for individuals living with schizophrenia.

Introduction: Deep surgical site infections (DSSI) usually require secondary treatments. The aim of this study was to compare the total length of hospitalisation (LOH), intensive care unit (ICU) duration, and total treatment costs in patients with DSSI versus without DSSI after open radical cystectomy (ORC) and urinary diversion., Material and Methods: Prospective case-control study in a tertiary care hospital in patients after ORC with urinary diversion during April 2008 to July 2012. DSSI was defined based on Centers for Disease Control and Prevention criteria. Matched-pair analysis for patients with versus without DSSI was done in 1:2 ratios. Patients with superficial surgical site infections (SSI) were excluded from analysis., Results: In total, 189 operations were performed. Thirty-eight patients (20.1%) developed SSI of which 28 patients (14.8%) had DSSI. Out of 28 patients, 27 (96.4%) were with DSSI and required surgical re-intervention. Due to insufficient matching criteria, 11 patients with DSSI were excluded from analyses. Consequently, 17 patients with DSSI were matched with 34 patients without DSSI. Significant differences were seen for median overall LOH (30 vs. 18 days, p < 0.001), median ICU duration (p = 0.024), and median overall treatment costs (€17,030 vs. €11,402, p = 0.011)., Conclusions: DSSI significantly increases LOH (67%) and treatment costs (49%), adding up to a financial loss for the hospital of approximately €5,500 in patients with DSSI., (© 2016 S. Karger AG, Basel.)

Glioblastoma (GBM) contains a population of stem-like cells that promote tumor invasion and resistance to therapy. Identifying and targeting stem cell factors in GBM may lead to the development of more effective therapies. High Mobility Group AT-hook 2 (HMGA2) is a transcriptional modulator that mediates motility and self-renewal in normal and cancer stem cells. We identified increased expression of HMGA2 in the majority of primary human GBM tumors and cell lines compared to normal brain. Additionally, HMGA2 expression was increased in CD133+ GBM neurosphere cells compared to CD133- cells. Targeting HMGA2 with lentiviral short hairpin RNA (shRNA) led to decreased GBM stemness, invasion, and tumorigenicity. Ectopic expression of HMGA2 in GBM cell lines promoted stemness, invasion, and tumorigenicity. Our data suggests that targeting HMGA2 in GBM may be therapeutically beneficial., Competing Interests: None., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Diffuse intrinsic pontine glioma (DIPG) is a highly morbid form of pediatric brainstem glioma. Here, we present the first comprehensive protein, mRNA, and methylation profiles of fresh-frozen DIPG specimens (n = 14), normal brain tissue (n = 10), and other pediatric brain tumors (n = 17). Protein profiling identified 2,305 unique proteins indicating distinct DIPG protein expression patterns compared to other pediatric brain tumors. Western blot and immunohistochemistry validated upregulation of Clusterin (CLU), Elongation Factor 2 (EF2), and Talin-1 (TLN1) in DIPGs studied. Comparisons to mRNA expression profiles generated from tumor and adjacent normal brain tissue indicated two DIPG subgroups, characterized by upregulation of Myc (N-Myc) or Hedgehog (Hh) signaling. We validated upregulation of PTCH, a membrane receptor in the Hh signaling pathway, in a subgroup of DIPG specimens. DNA methylation analysis indicated global hypomethylation of DIPG compared to adjacent normal tissue specimens, with differential methylation of 24 genes involved in Hh and Myc pathways, correlating with protein and mRNA expression patterns. Sequencing analysis showed c.83A>T mutations in the H3F3A or HIST1H3B gene in 77 % of our DIPG cohort. Supervised analysis revealed a unique methylation pattern in mutated specimens compared to the wild-type DIPG samples. This study presents the first comprehensive multidimensional protein, mRNA, and methylation profiling of pediatric brain tumor specimens, detecting the presence of two subgroups within our DIPG cohort. This multidimensional analysis of DIPG provides increased analytical power to more fully explore molecular signatures of DIPGs, with implications for evaluating potential molecular subtypes and biomarker discovery for assessing response to therapy.

The cellular reprogramming factor LIN28A promotes tumorigenicity in cancers arising outside the central nervous system, but its role in brain tumors is unknown. We detected LIN28A protein in a subset of human gliomas observed higher expression in glioblastoma (GBM) than in lower grade tumors. Knockdown of LIN28A using lentiviral shRNA in GBM cell lines inhibited their invasion, growth and clonogenicity. Expression of LIN28A in GBM cell lines increased the number and size of orthotopic xenograft tumors. LIN28A expression also enhanced the invasiveness of GBM cells in vitro and in vivo. Increasing LIN28A was associated with down-regulation of tumor suppressing microRNAs let-7b and let-7g and up-regulation of the chromatin modifying protein HMGA2. The increase in tumor cell aggressiveness in vivo and in vitro was accompanied by an upregulation of pro-invasive gene expression, including SNAI1. To further investigate the oncogenic potential of LIN28A, we infected hNSC with lentiviruses encoding LIN28A together with dominant negative R248W-TP53, constitutively active KRAS and hTERT. Resulting subclones proliferated at an increased rate and formed invasive GBM-like tumors in orthotopic xenografts in immunodeficient mice. Similar to LIN28A-transduced GBM neurosphere lines, hNSC-derived tumor cells showed increased expression of HMGA2. Taken together, these data suggest a role for LIN28A in high grade gliomas and illustrate an HMGA2-associated, pro-invasive program that can be activated in GBM by LIN28A-mediated suppression of let-7 microRNAs.

Objective: Findings from epidemiologic studies of trichloroethylene (TCE) exposure and liver cancer have been inconsistent. To quantitatively evaluate this association and to examine sources of heterogeneity, we conducted a meta-analysis of occupational studies of TCE exposure and liver/biliary tract cancer., Methods: We identified 14 occupational cohort studies of TCE exposed workers and one case-control study that met our inclusion criteria. Nine studies specifically identified TCE as a workplace exposure, and were classified as Group I cohort studies. Subcohorts of workers, identified within eight of these studies as more likely exposed to TCE than the total cohort, were analyzed separately., Results: The combined liver/biliary cancer summary relative risk estimate (SRRE) for all studies was 1.08 (95% CI 0.91-1.29; heterogeneity (H)-P-value=0.12). For the total study populations in the Group I cohorts, the SRRE was 1.14 (95% CI 0.93-1.39; H-P-value=0.05) and for the subcohorts, the SRRE was 1.30 (95% CI 1.09-1.55). Within this subcohort analysis, the association for the European studies of workers from various industries (SRRE=1.38; based on four studies) was higher than the association for the US studies of aerospace and aircraft workers (SRRE=0.97, based on four studies)., Conclusion: Although positive associations were observed for some analyses, results were inconsistent across occupational groups (aerospace/aircraft vs. other industries combined), study location, and incidence versus mortality endpoints. In addition, exposure-response trends were not observed consistently across studies. Interpretation is also limited by the potential impact of uncontrolled confounding by other occupational or lifestyle exposures such as smoking or alcohol consumption. Given these limitations, the currently available epidemiologic data are not sufficient to support a causal relation between occupational TCE exposure and liver/biliary cancer.

Methods: Meta-analysis and review of 14 occupational cohort and four case-control studies of workers exposed to trichloroethylene (TCE) to investigate the relation between TCE exposure and the risk of non-Hodgkin's lymphoma (NHL). Studies were selected and categorised based on a priori criteria, and results from random effects meta-analyses are presented., Results: The summary relative risk estimates (SRRE) for the group of cohort studies that had more detailed information on TCE exposure was 1.29 (95% CI 1.00 to 1.66) for the total cohort and 1.59 (95% CI 1.21 to 2.08) for the seven studies that identified a specific TCE exposed sub-cohort. SRREs for three studies with cumulative exposure information were 1.8 (95% CI 0.62 to 5.26) for the lowest exposure category and 1.41 (95% CI 0.61 to 3.23) for the highest category. Comparison of SRREs by levels of TCE exposure did not indicate exposure-response trends. The remaining cohort studies that identified TCE exposure but lacked detailed exposure information had an SRRE of 0.843 (95% CI 0.72 to 0.98). Case-control studies had an SRRE of 1.39 (95% CI 0.62 to 3.10). Statistically significant findings for the Group 1 studies were driven by the results from the subgroup of multiple industry cohort studies (conducted in Europe) (SRRE = 1.86; 95% CI 1.27 to 2.71). The SRRE for single industry cohort studies was not significantly elevated (SRRE = 1.25; 95% CI 0.87 to 1.79)., Conclusions: Interpretation of overall findings is hampered by variability in results across the Group 1 studies, limited exposure assessments, lack of evidence of exposure response trends, lack of supportive information from toxicological and mechanistic data, and absence of consistent findings in epidemiologic studies of exposure and NHL. Although a modest positive association was found in the TCE sub-cohort analysis, a finding attributable to studies that included workers from multiple industries, there is insufficient evidence to suggest a causal link between TCE exposure and NHL.

Six cases of coagulase-negative staphylococcal mediastinitis were identified in the latter half of 1999. A new preoperative cleansing solution was suspected by hospital staff to be a factor in the outbreak. We evaluated this possible risk factor along with other known and suspected surgical site infection risk factors in this case-control study.

Analysis of settled dust collected from carpeting and furnishings is occasionally used by investigators to determine whether an environment contains unusual fungi. Little information is available concerning the types and concentrations of culturable fungi present on textile surfaces in normal residential settings not affected by unusual mold reservoirs, such as from fungal growth sites within the built environment. This study presents the results of the collection and analysis of surface dust from 26 residential environments that were prescreened by interview, physical inspection, and air sampling to limit the surface dust collection to structures in which there was no history of water intrusion, flooding, plumbing leaks, signs of mold growth, or evidence of unusual airborne fungal spore types or concentrations. In those structures found to have no history or indications of water events or unusual fungi, surface dust was vacuumed from prescribed horizontal areas on carpet and textile-covered furnishings. These samples were then subjected to fungal culture, from which viable colonies were enumerated and identified. Based on the study results, it does not appear reasonable that the frequently quoted total fungi concentration exceeding 10(5) CFU/g is definitive evidence that a residential surface is contaminated with unusual amounts of culturable fungi. Collocated samples collected from eight side-by-side carpets sections revealed poor reproducibility. While settled dust sampling may be appropriate for determining the fungal status of a localized area, or as a gross screening tool, using settled dust results alone to establish the presence of unusual fungal types or concentrations within a structure appears to be inappropriate, and using settled dust results with other investigative methods, such as visual observations and air sampling, requires cautious interpretation.

Two versions of an amperometric detector with a copper working electrode have been constructed and tested for high-performance liquid chromatography (HPLC). The performance of the detectors was studied using selected amino acids. The dependence of the detector response on the mobile phase flow-rate was studied in the range common in both macro- and microcolumn HPLC (5 microliter/min to 1.0 ml/min). It has been found that the detection sensitivity generally increases with decreasing flow-rate, i.e., the detector response is governed by the rate of the complexation reaction between the cupric ions and the solutes. This fact makes amperometric detection with a copper electrode especially useful for microcolumn separations. For all 20 amino acids studied, calibration curve parameters and detection limits have been determined; the latter vary from 0.4 to 18 ng in the injected volume. The amino acids can also be sensitively detected in a medium of 0.1-1.0 M ammonia, which is promising for the use of strong anion exchangers in amino acid separations. Choline can also be detected at a copper electrode, with a detection limit of 40 ng. An HPLC method with amperometric detection at a copper electrode has been developed for the determination of lysine, methionine and choline in fodder biofactors.