PubMed HealthSearch

SEARCH · PubMed Health

Results for “Automated phenotyping”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

Is immunochemical determination of haptoglobin phenotype dependent?

Immunochemical methods have been used to determine the concentration of haptoglobins. The dependence on the phenotype was tested with highly purified Hp 2-1, Hp 2-2 and Hp 1-1, by immunonephelometry and radial immunodiffusion (RID). Measurements with three different instruments: automated immunonephelometer (AIP, Technicon), laser nephelometer (LN, Behring) and immunochemistry system (ICS, Beckman) were performed. For each type of apparatus antisera against a pool of haptoglobins were provided by the respective manufacturers. Some experiments were done with an antiserum to the haptoglobin heavy chain prepared in the laboratory. This study shows that haptoglobin determination depends neither on the physical geometry of the instruments or on the type of antiserum used in this work. In contrast, the data display a dependence on haptoglobin phenotype. When Hp 2-1, the most common phenotype, is taken as a standard, thd values obtained for Hp 2-2 are in good agreement with those obtained for Hp 2-1. However, the values obtained for Hp 1-1 are overestimated unless they are corrected by an experimental factor which has been determined in this study.

Haptoglobins

Analysis of T cell receptors in rheumatoid arthritis: the increased expression of HLA-DR antigen on circulating gamma delta+ T cells is correlated with disease activity.

The phenotypic characteristics of peripheral blood T cells, isolated from 37 rheumatoid arthritis (RA) patients and 17 healthy controls were determined with special emphasis on gamma delta+ T cells and CD4-CD8- alpha beta+ T cells. Two- and three-colour automated flow cytometry analyses were performed using a panel of MoAbs directed against differentiation antigens and T cell receptor molecules. The results demonstrated: (i) no significant difference between the percentages of CD4-CD8- alpha beta+ T cells in patients and controls; (ii) a significant decrease of the gamma delta+ T cell level in the peripheral blood of RA patients relative to controls; (iii) phenotypic abnormalities of circulating gamma delta+ T cells in RA patients suggestive of an activation status in vivo. These abnormalities included a significant reduction in the density of the T cell differentiation antigen CD3 and an increase in the expression of HLA-DR antigen. The level of circulating HLA-DR+/gamma delta+ T cells was significantly higher in patients with active disease. HLA-DR+/gamma delta+ T cells were also present in the synovial fluid obtained from three patients with an active disease. In addition, preliminary experiments showed that the activated gamma delta+ T cells were predominantly V delta 1. Taken together, these data support the involvement of gamma delta+ T cells in the pathogenesis of RA.

Adult

Automated measurement of lipoprotein(a) by immunoturbidimetric analysis.

Immunoturbidimetric analysis of lipoprotein(a) in plasma or serum was developed for use on the Roche COBAS FARA II and COBAS MIRA clinical chemistry analyzers. The components of the assay are: (1) buffer consisting of 2.25% polyethylene glycol in phosphate-buffered saline, 0.2% gelatin, and a surfactant; (2) fractionated goat anti-human lipoprotein(a) IgG; (3) five standards with lipoprotein(a) concentrations ranging from 0.05 to 1.0 g/l; (4) two controls with concentrations of approximately 0.2 and 0.5 g/l. The analyzer delivers sample and buffer, incubates the reaction mixture at 37 degrees C for 5 min, delivers neat lipoprotein(a) antibody, and incubates for an additional 10 min. The lipoprotein(a) concentration of samples is calculated by the COBAS DENS (Data Evaluation for Non-linear Standard Curves) option by fitting the standard curve values to a four-parameter logit-log curve model. Total imprecision results (CV%) for the FARA II and MIRA were under 11% (NCCLS protocol EP5-T). The assay is linear beyond the highest calibrator to 2.6 g/l. No interference was observed for plasminogen up to 2.3 g/l, apolipoprotein B up to 4.36 g/l, hemoglobin up to 10 g/l, bilirubin up to 4.0 g/l, and triglycerides up to 4.36 g/l. Comparison with a double monoclonal ELISA used at the Northwest Lipid Research Laboratories yielded: R = 0.970, slope = 1.013, and y-intercept = 0.00009 (n = 37). Comparison with a commercially available ELISA kit for lipoprotein(a) yielded: r = 0.987, slope = 1.243, and y-intercept = 0.024 (n = 40). This assay provides rapid, accurate, and precise screening of lipoprotein(a) in serum or plasma.

Antibody Formation

Emergence of a Novel, Phenotypically Difficult-to-Detect Vancomycin-Resistant Enterococcus faecium Clone (ST117/CT7799).

A significant increase of vancomycin-resistant Enterococcus faecium (VREfm) infections was observed in South-Eastern Austria since 2024. The prolonged outbreak is caused by a novel vanB-VREfm clone (ST117/CT7799, "VREfmstyr"). This study characterizes the atypical difficult-to-detect resistance phenotype and assesses the genomic relatedness of the isolates. Patient and outbreak characteristics were investigated including whole genome sequencing of the isolates. Sensitivity of broth microdilution (BMD), gradient tests (GT), disk diffusion (DD), and automated susceptibility testing (VITEK2) was compared. The performance of commercial screening media was evaluated. From sporadic detections in early 2024 case numbers began to rise during the year. In 30/31 (97%) of all cases, intra-hospital transmission was considered likely and an association with invasive procedures was identified in most cases. Core genome multilocus sequence typing revealed only six allelic differences between VREfmstyr isolates collected in a 12-month period, all belonging to the E. faecium ST117/CT7799 lineage. BMD detected vancomycin resistance (MIC > 4 mg/L) in no more than 16/31 (52%) of isolates after 24 h incubation, while GT and DD misclassified all isolates. Only prolonged incubation improved the performance of these assays. VITEK2 analysis, however, correctly classified all 31 isolates. Of four commercially available VRE-screening agars, only one was capable of detecting VREfmstyr after 24 h incubation. The emergence and clonal dissemination of VREfm ST117/CT7799 reveals a serious diagnostic gap as commonly used diagnostic algorithms fail to reliably detect this resistance phenotype. Our findings should help to further evaluate the true geographical distribution and clinical significance of this novel VREfm clone.

Enterococcus faecium

Accelerate Your Science: Direct-to-Biology Strategies in Medicinal Chemistry.

Direct-to-biology (D2B) is a powerful strategy that accelerates early drug discovery. It enables compounds to be synthesized in miniaturized formats and evaluated directly as crude reaction mixtures. This bypasses the need for purification during the initial design-make-test cycle. Advances in robust synthetic methodologies, automation, reaction miniaturization, and biological screening have transformed D2B from a proof-of-concept approach into a versatile medicinal chemistry platform. This platform is applicable to fragment optimization, covalent ligands, macrocycles, proteolysis-targeting chimeras (PROTACs), molecular glues, and cellular phenotypic screening. This perspective focuses on the synthetic transformations, assay technologies, and platform implementations that drive modern D2B workflows. It emphasizes reaction robustness, assay compatibility, and practical implementation. Analysis of the current literature revealed that D2B is more governed by reaction reliability than synthetic diversity. Amide coupling and click chemistry dominate reported workflows, while more complex transformations remain underexplored. We discuss the complementary strengths and limitations of biochemical, biophysical, and cellular readouts, identify current bottlenecks in reaction scope and data management, and highlight emerging opportunities arising from reaction miniaturization, machine learning, automated experimentation, and advanced synthetic methodologies. Rather than replacing conventional medicinal chemistry, D2B fundamentally shifts experimental effort from purification toward early biological validation and is poised to become an integral component of future medicinal chemistry workflows.

Humans

Phenotypic overlaps between pleomorphic malignant T-cell lymphomas and mixed-cellularity Hodgkin's disease.

Histologically diagnosed, or in part questionable, malignant pleomorphic peripheral T-cell lymphomas (pPTCLs, n = 16) and mixed-cellularity Hodgkin's disease (MCHD, n = 12) were objectively compared by the use of combined immunohistochemistry on paraffin sections, test-point analysis of tissue components, and semi-automated nuclear morphometry on semi-thin resin sections. Classical, qualitative histomorphological distinction of these sub-types of lymphomas proved to be valid and is probably still the best method. Quantitative discriminant features, in order of decreasing significance, were: (i) expression by large atypical cells (LACs) of CD45R0, CD43 and CD45 in pPTCLs, and of CD30 and CD15 in MCHD; (ii) means and standard deviations (SDs) of LAC nuclear-profile areas (greater in MCHD than in pPTCLs); (iii) expression of CD3 by LACs in pPTCLs; (iv) prominence of small lymphoid cells in MCHD; (v) higher percentage of medium-sized lymphoid cells in pPTCLs; and (vi) higher SDs of nuclear-profile circularity factor of small lymphoid cells in MCHD. The medians of the largest nucleolar profile areas in LACs per field did not differ in pPTCLs and MCHD, but dispersion of individual values towards higher levels was significantly greater in the latter. Stepwise discriminant analysis of test point and nucleometric variables that best distinguished pPTCLs from MCHD revealed considerable overlaps, and questionable cases tended to be intermediate between the two. In conclusion, our results confirm and expand the notion of intra-group heterogeneity, with indistinct borders and the existence of intermediate phenotypes between these two taxonomic categories of malignant lymphomas.

Adolescent

Evaluating 12 automated, whole-genome sequencing analysis pipelines for Mycobacterium tuberculosis complex: a comparative study.

BACKGROUND: Reliance on complex, custom-built bioinformatics pipelines is a barrier to the implementation of whole-genome sequencing (WGS) of Mycobacterium tuberculosis in high-burden settings in some low-income and middle-income countries (LMICs). Automated analysis pipelines could address this inequity in access to WGS-based diagnostics and surveillance. This study aimed to systematically evaluate the performance and usability of publicly available WGS pipelines for M tuberculosis. METHODS: We identified automated M tuberculosis WGS analysis pipelines through searches of PubMed and GitHub from database inception up to Aug 31, 2024. Accuracy, cost, accessibility, and scalability were assessed for each pipeline. We evaluated the accuracy of genotypic drug susceptibility testing (gDST) using publicly available sequences with phenotypic susceptibility data for 12 antituberculosis drugs. We estimated pooled sensitivity and specificity for each pipeline, across all drugs, by conducting a bivariate meta-analysis, with random effects representing between-drug variability. Lineage classifications were compared, and a previously epidemiologically well-characterised dataset was used to compare measures of genomic relatedness. FINDINGS: Among 28 candidate pipelines, 16 were excluded as they were unmaintained and inexecutable. 12 pipelines (11 compatible with Illumina and four compatible with Nanopore), all free to use, were included for evaluation. Six pipelines processed and stored data remotely, but for five of these six, scalability was limited by the need to upload sequences through web portals. For local processing pipelines, scalability was dependent on substantial local computational resources, data storage capacity, and command-line interfaces that limited user-friendliness. Only one of six remote-processing pipelines removed human DNA sequences before server upload. gDST was similarly accurate across ten of 11 Illumina-compatible pipelines and three of four Nanopore-compatible pipelines. All pipelines classified the main lineages consistently, although there were differences at sublineage resolution. Outputs from three of four pipelines reporting genomic relatedness were compatible with commonly cited single nucleotide polymorphism difference thresholds. INTERPRETATION: Numerous automated analysis pipelines capable of enhancing equity in M tuberculosis WGS are available. Given the overall similarities between the pipelines evaluated in this study in terms of gDST performance, lineage classification, and genomic relatedness inference, non-functional attributes such as availability, accessibility, scalability, and privacy could represent the point of difference for prospective users in LMICs with a high burden of tuberculosis. FUNDING: The Rhodes Trust, Wellcome, Ellison Institute of Technology, and the UK National Institute for Health and Care Research Oxford Biomedical Research Centre.

Mycobacterium tuberculosis

Characterization of mutations in phenotypic variants of hypoxanthine phosphoribosyltransferase deficiency.

The Lesch-Nyhan disease is caused by an almost complete lack of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). Partial HPRT-deficiency, associated with less severe phenotype, has also been identified. We have characterized mutations occurring in HPRT cDNA isolated from patients with HPRT-deficiency with an emphasis on examining the more unusual partial variants of HPRT-deficiency. HPRT cDNA was amplified by PCR, cloned and analyzed by automated DNA sequence analysis. Twenty-two, unrelated individuals with HPRT deficiency were studied including eight classic Lesch-Nyhan patients and fourteen patients representing the different groups of partial HPRT deficiency. We found a diverse pattern of mutations with point mutations accounting for the majority of abnormal HPRT genes. Nonsense mutations and exon deletions were only found in HPRT cDNA isolated from classic Lesch-Nyhan patients. Mutations associated with partial HPRT-deficiency were frequently located in the amino terminal part of the molecule. A CpG mutational hot spot was identified at the position for Arg-51 in the HPRT protein. Two hyperuricemic patients exhibited unusual splice site mutations: in one this led to the creation of an additional exon in the HPRT gene and in the other part of exon 6 was missing in a subpopulation of the transcripts, producing the effect of a dominant, negative mutation.

Amino Acid Sequence

Optimized GMP-grade production of non-viral Sleeping Beauty-generated CARCIK cells for enhanced fitness and clinical scalability.

BACKGROUND: Strict adherence to GMP guidelines and regulatory compliance is crucial when transitioning from research to clinical-grade production of ATMPs like CAR T cells. The success of CAR T cell therapy in treating hematological malignancies highlights the need for closed or automated systems to ensure quality and efficacy. Recent evidence also suggests that ex vivo culture conditions can significantly impact CAR T cell functionality. METHODS: We present our optimized methodology for expanding Sleeping Beauty transposon-engineered Chimeric Antigen Receptor-Cytokine-Induced Killer (CARCIK) cells using G-Rex devices and evaluate its impact on CARCIK cell phenotype and T cell fitness. RESULTS: Building on our previously validated protocol, we introduced key simplifications to optimize the CARCIK differentiation process. Delaying the nucleofection step eliminated the need for feeder cells while maintaining efficient CAR expression and high cell viability. Transitioning from T-flasks to G-Rex bioreactors reduced operator hands-on time from 21 to 28 days to 14-17 days and resulted in a less differentiated CARCIK cell product. Metabolic and transcriptional analyses showed that the novel protocol improves CARCIK cell fitness and in vivo efficacy against B-cell lymphoma. The novel method was validated in Good Manufacturing Practices (GMP) conditions at our two Cell Factories and yielded enough numbers of CARCIK-CD19 cells for clinical use. CONCLUSIONS: Optimizing non-viral CARCIK cell production using G-Rex bioreactors and refined timing adjustments has streamlined the workflow, enhanced cell fitness, and resulted in a highly effective therapeutic product with demonstrated in vivo efficacy in mice. These improvements reduced manipulation and contamination risks, while optimizing logistics and space efficiency, facilitating allogeneic CARCIK generation for a current phase I/II clinical trial (NCT05869279) in patients with R/R CD19 + non-Hodgkin Lymphoma (B-cell NHL) and Chronic Lymphocytic Leukemia (CLL), confirming the approach's scalability and clinical potential.

Humans

Mendelian randomisation for rheumatology: beyond hype-what it's good for, what it can't do, and how to read it critically.

Mendelian randomisation (MR) has become abundant in the literature, with variation in quality and frequent overinterpretation of causality. This creates a problem for clinical readers, reviewers, and editors: some MR studies can sharpen causal thinking, prioritise drug targets, and challenge misleading observational claims, whereas others are little more than automated exposure-outcome scans with causal claims disproportionate to the evidence. MR can strengthen causal inference when randomised trials are impractical and conventional observational studies are vulnerable to confounding, reverse causation, or selection bias. In rheumatology, credible MR can contribute to questions about disease aetiology, modifiable risk factors, therapeutic target validation, adverse-effect anticipation, and phenotype validation. However, its interpretation depends on whether the exposure is plausibly instrumentable, whether the genetic instruments are biologically defensible, whether assumptions are interrogated in ways appropriate to the design, and whether findings are triangulated with clinical, observational, experimental, and mechanistic evidence. Instead of recapitulating all methodological issues of MR, this review aims to help rheumatologists distinguish robust MR from weak or overinterpreted analyses quickly. We provide an accessible framework for reading and triaging MR studies in rheumatology. Papers that use poorly justified instruments, treat medication use as drug-target evidence, interpret genetic liability as diagnosis, rely on mechanical sensitivity analyses, ignore prior evidence or ask no clinically meaningful question can often be passed over by readers. The goal is not to discourage MR in rheumatology, but to raise the standard; useful MR should clarify causal reasoning rather than simply generate another statistically significant association.

Journal Article

scBaseCount: An AI agent-curated, standardized, auto-updated single-cell data repository.

Single-cell RNA sequencing has transformed cell biology by enabling precise transcriptomic measurements of individual cells. The Sequence Read Archive (SRA) is the largest public repository of sequencing reads, yet much of it remains underutilized due to unstandardized metadata. Here, we introduce scBaseCount, a database that leverages an AI agent to automate discovery and metadata extraction and standardize data processing. Built by mining all 10x Genomics datasets, scBaseCount is the largest public repository of single-cell gene expression data, comprising over 502 million cells across 27 organisms and 75 tissues. It offers an unbiased view of the data landscape within the SRA and enables the training of more performant computational models through access to broader phenotypic diversity. Uniform processing enables measurement of both intronic and exonic reads and non-coding gene expression and improves alignment across experiments. Moreover, scBaseCount provides a blueprint for how AI can be leveraged to autonomously curate biological data repositories.

Single-Cell Analysis

Distinguishing specific from broad genetic associations between external correlates and common factors.

MOTIVATION: Within the genomic structural equation modelling (genomic SEM) framework, common factors are often used to index shared genetic etiology across constellations of genome-wide associations studies (GWASs) phenotypes. A standard common pathway model, in which a genetic association is estimated between an external GWAS phenotype and a common factor, assumes that all genetic associations between the external GWAS phenotype and the individual indicator phenotypes are mediated through the factor. This assumption can be tested using the QTrait statistic, which compares the common pathway model to an independent pathways model that allows for direct genetic associations between the external GWAS phenotype and the individual indicators of the factor. However, QTrait is not designed to identify either the magnitude or the source of this heterogeneity. RESULTS: We expand upon the QTrait approach by describing an effect size index that quantifies the degree to which the common pathways model is violated, and we provide a systematic approach for empirically identifying specific direct pathways between an external trait and indicator traits. Our method comprises a series of omnibus tests and outlying indicator detection algorithms indexing the heterogeneity of associations between the genetic component of external traits and the individual indicators of common factors. We provide a set of automated functions which we apply to investigate the patterns of genetic associations across a set of external correlates with respect to indicators of general cognitive ability and case-control and proxy GWAS indices of Alzheimer's disease. AVAILABILITY AND IMPLEMENTATION: The Genomic SEM R package and the QTrait function is available at https://github.com/GenomicSEM/GenomicSEM. The QTrait function tutorial is available at https://github.com/GenomicSEM/GenomicSEM/wiki/8.-Tutorials. To ensure reproducibility of the analyses presented in this manuscript, the exact version of the QTrait function used, along with input data and scripts, has been archived on Zenodo (DOI: https://doi.org/10.5281/zenodo.17186083).

Genome-Wide Association Study

[Groupamatic 360 C1 and automated blood donor processing in a transfusion center].

Automation of donor management flow path is controlled by: --a 3 slip "port a punch" card, --the groupamatic unit with a result sorted out on punch paper tape, --the management computer off line connected to groupamatic. Data tracking at blood collection time is made by punching a card with the donor card used as a master card. Groupamatic performs: --a standard blood grouping with one run for registered donors and two runs for new donors, --a phenotyping with two runs, --a screening of irregular antibodies. Themanagement computer checks the correlation between the data of the two runs or the data of a single run and that of previous file. It updates the data resident in the central file and prints out: --the controls of the different blood group for the red cell panel, --The listing of error messages, --The listing of emergency call up, --The listing of collected blood units when arrived at the blood center, with quantitative and qualitative information such as: number of blood, units collected, donor addresses, etc., --Statistics, --Donor cards, --Diplomas.

Autoanalysis

Difficult-to-treat resistant Gram-negative bacteria and genomic resemblances between colonization and infection among patients in an intensive care unit of a tertiary care hospital in Bangladesh.

Colonization with difficult-to-treat-resistant Gram-negative bacteria (DTR-GNB) increases the risk of subsequent infections with limited treatment options. This study aimed to assess the burden of DTR-GNB colonization in ICU patients, explore its association with clinical outcomes, and examine genomic similarities. This secondary analysis included patients enrolled within 24 h of ICU admission between July 2023 and January 2024. Rectal swabs were collected at enrollment, on days 3, 7, and weekly during ICU stay to detect colonization. Bacterial isolates grown on selective chromogenic agar media were identified and tested for antimicrobial susceptibility using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and automated broth microdilution, respectively. Blood, urine, and/or tracheal aspirate cultures were performed if clinically suspected sepsis. Whole-genome sequencing (WGS) was performed on paired colonization and infection isolates, and genomic relatedness was assessed using FastANI, core-genome single-nucleotide polymorphism (SNP) analysis, and phylogenetic reconstruction. Among 373 patients, 181 (48.5%) were colonized with DTR-GNB; 76 (20.4%) at enrollment, and 105 (53.0%) acquired during hospital stay. Among 52 (13.9%) patients evaluated for suspected infection, 30 (57.7%) had positive cultures, predominantly Acinetobacter baumannii (n = 15) and Klebsiella pneumoniae (n = 11) of DTR-phenotypes. Compared to non-colonized patients, patients colonized with DTR-GNB had higher risks of infections (risk ratio [RR]: 2.18, 95% CI: 1.27-3.76) and longer ICU stays (median 7 vs 2 days, P < 0.001). DTR-GNB-infected patients had a higher risk of death (RR: 1.57, 95% CI: 1.34-1.84) compared to patients without DTR-GNB infection. WGS revealed that 13 of 14 paired colonization-infection isolates were conspecific, with three pairs being highly clonal; whereas the remaining pairs showed greater genomic divergence, consistent with the SNP and phylogenetic analyses. While common, more than half acquired DTR-GNB colonization from the ICU. Its association with subsequent infection and prolonged ICU stays underscores the need for enhanced infection prevention and control measures to mitigate nosocomial transmission and improve patient outcomes.IMPORTANCEThis study underscores the growing threat posed by difficult-to-treat resistant Gram-negative bacteria (DTR-GNB) in intensive care units. Nearly half of critically ill patients were colonized, with a considerable proportion acquiring these multidrug-resistant organisms during their ICU stay. Colonization with these pathogens substantially increased the risk of subsequent infections, even by the same colonizing strain, prolonged ICU stays, and likely worsened clinical outcomes due to the unavailability of susceptible antibiotics. Alarmingly, more than 90% of patients infected with DTR-GNB expired in the hospital. These findings highlight the urgent need for robust infection prevention and control strategies to curb nosocomial transmission and mitigate the impact of DTR-GNB on vulnerable patient populations. Addressing this emerging resistance phenotype is critical to improving patient safety and reducing the burden on healthcare systems.

Humans

PAT: An Image Analysis Tool for Automated Scoring of Pollen in Alexander-Stained Anthers.

Quantitative pollen viability analysis is a critical but labor-intensive step in plant reproductive biology. Existing deep-learning Segment Anything Models (SAM) fail to reliably segment viable pollen in Alexander-stained anthers. To address this, we fine-tuned an existing Cellpose-SAM model for pollen segmentation. We integrated it into PAT (Pollen Analysis Tool), a cross-platform desktop application. PAT features instance segmentation with interactive quality control, an in-app model retraining module, and publication-ready statistical outputs. We deployed PAT in an EMS suppressor screen of semi-sterile Arabidopsis smg7-6 mutants, enabling efficient candidate prioritization for whole-genome sequencing and mapping of the candidate mutation. This screen led to the identification of a point mutation in CAP-D2 (capd2-2), a Condensin I subunit, that rescues the smg7-6 meiotic phenotype. Notably, mutation in a Condensin II subunits (CAP-D3 and CAP-H2) does not confer rescue. Further characterization suggests the capd2-2 allele is hypomorphic, showing no defects in vegetative growth, chromocenter compaction, or transposable element silencing. Collectively, we demonstrate that accessible AI tools have the potential to bridge gaps in plant phenotyping and accelerate the pace of biological discovery.

Alexander staining

Nature and nurture in the expression of diabetes mellitus and its vascular manifestations.

The prevailing concept of etiologic heterogeneity for the diabetes mellitus syndrome is one of multiple genetic factors interacting with a variety of environmental influences. Variation in expression of the disorder, particularly the need for insulin, does not correlate with known etiologic distinctions. There is much evidence for genetic heterogeneity, as well as phenotypic variation when etiology can be presumed to be identical. The vascular manifestations of diabetes include microangiopathy unique to diabetes and larger vessel disease that differs from that of normal aging only by its prematurity. There is as much evidence for heterogeneity of the vascular expression as there is for glucose intolerance. Approximately 25% of persons with insulin-dependent diabetes may never develop the microvascular disease. The pathogenesis of vascular disease in diabetes may involve a number of abnormalities of plasma, circulating cells, and vascular tissue. Were absolute control of glycemia possible, some of the contributing factors involved in vasculopathy would possibly be alleviated. In the absence of automated physiologic insulin replacement the potential deleterious effect of our current methods of treatment might be reduced by specific inhibition of excess catecholamine, growth hormone and/or glucagon responses.

Aging

Primary structure of a chloramphenicol acetyltransferase specified by R plasmids.

Naturally occurring isolates of chloramphenicol-resistant bacteria commonly synthesise chloramphenicol acetyltransferase (EC 2.3.28; CAT) in amounts which are sufficient to account for the resistance phenotype and often harbour plasmids which carry the structural gene for CAT. The findings of CAT in such diverse prokaryotes as Proteus mirabilis, Agrobacterium tumefaciens, Streptomyces sp., and a soil Flavobacterium has led to speculation concerning the origin and evolution of the more commonly observed CAT variants specified by plasmids in clinically important bacteria. To provide a more solid basis for studying the evolution and spread of CAT within prokaryotes we chose to determine the complete amino acid sequence of a type I variant of CAT, the variant known to be associated with most F-like plasmids conferring chloramphenicol resistance. The sequence has been determined by combining the results obtained from manual and automated sequential degradation with those obtained by mass spectrometry of peptides generated by enzymatic digestion. The directly determined primary structure is identical with that predicted by the DNA sequence analysis of the chloramphenicol resistance transponson Tn9 known to specify a type I variant of chloramphenicol acetyltransferase.

Acetyltransferases

Reconstruction of ancestral plant genomes for inter-crop translational research.

We present Ancestral Genome Reconstruction (AGR), an exploratory framework for the automated inference of "paleogenomes" from large-scale comparative datasets. By analyzing 84 extant angiosperm species, we reconstructed 10 key ancestral angiosperm genomes millions of years old. These reconstructed ancestors were instrumental in (1) estimating when angiosperms emerged, when major botanical families originated, and when shared ancestral whole-genome duplication events occurred; and (2) tracing the evolutionary trajectories of ancestral chromosomes and genes, especially those that may have driven the emergence of key life-history traits (e.g., woody vs. herbaceous, aquatic vs. terrestrial, C3 vs. C4, and symbiotic root-nodulating vs. non-nodulating species). We demonstrated that these paleogenomes serve as tractable backbones for inter-crop translational research. Through an open-access web tool, OrthoViewer, we identified orthologs that have retained the same ancestral genomic context, favoring the identification of genes associated with "phenologs"- orthologous genes across species driving analogous phenotypes, traits, or processes-exemplified by FUWA for yield components, FLC for flowering time, and DDM1 for DNA methylation. Taken together, this study provides a testable paleogenomic workflow, opening novel avenues for integrating evolutionary genomics data into modern climate-smart crop breeding and supporting the agroecological transition.

Genome, Plant