Compatible and Incompatible Interactions Between Callus Tissue and Mycorrhizal or Pathogenic Fungi

Tissue cultures of Nicotiana tabacum were utilized to investigate the mechanisms associated with host specificity and non-host incompatibility in mycorrhizal and pathogenic fungi. They were tested for expression of resistance to different species of mycorrhizal fungi and to a fungal pathogen of tobacco, Thielaviopsis basicola , by monitoring the production of callose, phenolic compounds and peroxidases in dual cultures. Tobacco cells reacted to the presence of all the mycorrhizal fungi with callose deposits, whereas callose was nearly always absent in tobacco cells inoculated with their pathogen T. basicola. The broad-host range ectomycorrhizal fungi Hebeloma crustuliniforme, Lac-caria laccata and Suilhis granulatus elicited less intense responses than did Hymenoscyphus ericae. The results obtained for phenolic production and peroxidase activity were consistently similar to those obtained for callose deposition. They showed that H. ericae , an endomycorrhizal symbiont of Ericaceae, was highly incompatible with tobacco cells and that the tobacco pathogen T. basicola did not elicit strong reactions in the cells of its host. In this paper, the possibility of utilizing callus cultures as a simple model system to study both the different degrees of compatibility and the early events of recognition between mycorrhizal fungi and their host or non-host plants is discussed.     

COVID-19 plasma proteome reveals novel temporal and cell-specific signatures for disease severity and high-precision disease management

Coronavirus disease 2019 (COVID-19) is a systemic inflammatory condition with high mortality that may benefit from personalized medicine and high-precision approaches. COVID-19 patient plasma was analysed with targeted proteomics of 1161 proteins. Patients were monitored from Days 1 to 10 of their intensive care unit (ICU) stay. Age- and gender-matched COVID-19-negative sepsis ICU patients and healthy subjects were examined as controls. Proteomic data were resolved using both cell-specific annotation and deep-analysis for functional enrichment. COVID-19 caused extensive remodelling of the plasma microenvironment associated with a relative immunosuppressive milieu between ICU Days 3–7, and characterized by extensive organ damage. COVID-19 resulted in (1) reduced antigen presentation and B/T-cell function, (2) increased repurposed neutrophils and M1-type macrophages, (3) relatively immature or disrupted endothelia and fibroblasts with a defined secretome, and (4) reactive myeloid lines. Extracellular matrix changes identified in COVID-19 plasma could represent impaired immune cell homing and programmed cell death. The major functional modules disrupted in COVID-19 were exaggerated in patients with fatal outcome. Taken together, these findings provide systems-level insight into the mechanisms of COVID-19 inflammation and identify potential prognostic biomarkers. Therapeutic strategies could be tailored to the immune response of severely ill patients.     

Genetic Diversity of Isolates of Glomus mosseae from Different Geographic Areas Detected by Vegetative Compatibility Testing and Biochemical and Molecular Analysis

We detected, for the first time, the occurrence of vegetative incompatibility between different isolates of the arbuscular mycorrhizal fungal species Glomus mosseae. Vegetative compatibility tests performed on germlings belonging to the same isolate showed that six geographically different isolates were capable of self-anastomosing, and that the percentage of hyphal contacts leading to fusions ranged from 60 to 85%. Successful anastomoses were characterized by complete fusion of hyphal walls, protoplasm continuity and occurrence of nuclei in the middle of hyphal bridges. No anastomoses could be detected between hyphae belonging to different isolates, which intersected without any reaction in 49 to 68% of contacts. Microscopic examinations detected hyphal incompatibility responses in diverse pairings, consisting of protoplasm retraction from the tips and septum formation in the approaching hyphae, even before physical contact with neighboring hyphae. Interestingly, many hyphal tips showed precontact tropism, suggesting that specific recognition signals may be involved during this stage. The intraspecific genetic diversity of G. mosseae revealed by vegetative compatibility tests was confirmed by total protein profiles and internal transcribed spacer-restriction fragment length polymorphism profiles, which evidenced a higher level of molecular diversity between the two European isolates IMA1 and BEG25 than between IMA1 and the two American isolates. Since arbuscular mycorrhizal fungi lack a tractable genetic system, vegetative compatibility tests may represent an easy assay for the detection of genetically different mycelia and an additional powerful tool for investigating the population structure and genetics of these obligate symbionts.     

Molecular cloning and sequencing of human palmitoyl-CoA ligase and its tissue specific expression

A complimentary DNA clone encoding the entire human palmitoyl-CoA ligase has been isolated from a liver cDNA library and sequenced in it's entirety. The predicted product is a 699 amino acid protein. Southern analysis utilizing the human palmitoyl-CoA ligase gene as a probe revealed varying degrees of similarity amongst various mammalian species. The palmitoyl-CoA ligase gene is highly expressed in liver, heart, skeletal muscle and kidney, and to a lesser extent in brain, lung, placenta and pancreas. The expression of palmitoyl-CoA ligase in various tissue parallels the function of this enzyme in the metabolism of fatty acids in these tissues.     

XY gonadal dysgenesis and gonadoblastoma: a study in two sisters with a cryptic deletion of the Y chromosome involving the SRY gene

This paper reports a case of XY gonadal dysgenesis in two sisters. Both patients presented an eunochoid female phenotype with normal external genitalia. At laparotomy, the elder sister was found to have bilateral gonadoblastoma. Cytogenetic studies, which included G and C banding and in situ hybridization, showed that the patients had an apparently normal 46, XY karyotype. PCR analyses revealed absence of the conserved portion (HMG box) of the SRY gene and of the Y chromosome pseudoautosomal boundary region sequence in both patients. The presence of the ZFY sequence was detected by Southern hybridization in the two affected sisters. The patients' father (46, XY, no mosaicism detected in peripheral blood lymphocytes) was positive for SRY and ZFY sequences. The occurrence of gonadoblastoma is discussed in terms of the genetic factors that may lead to tumor development.     

Host related factors affecting oviposition behavior in Brachymeria intermedia

Some behavioral and physical defenses of Lymantria dispar (L.) pupae are described. It was found that the layer of webbing surrounding pupae significantly reduced oviposition rates in the pupal parasitoid Brachymeria intermedia (Nees) (Hymenoptera, Chalcididae). The reasons for this reduction and consequent parasitoid responses were investigated. The role of these behaviors in this host parasitoid relationship are discussed.

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Résumé Le comportement défensif des chrysalides de Lymantria dispar L. consiste en cambrage et en tournoiement. Les chrysalides encoconées étaient plus sensibles aux stimuli tactiles que celles qui ont été extraites des cocons. Brachymeria intermedia Nees avait moint de succès dans l'insertion complète de la tarière dans des chrysalides encoconées qu'extraites, car elles devenaient empêtrées dans le cocon quand la chrysalide se défendait. Il y avait différentes réponses du parasitoïde à l'empêtrement. Elles comprenaient l'abandon de l'attaque par un départ, la remise en selle sur l'hôte, la morsure à travers les fils du cocon, l'attaque d'un hôte voisin, le repos ou la toilette. Les taux d'insertion de la tarière pouvaient être augmentés par l'élimination artificielle de quelques fils. La durée des opérations était plus courte sur les chrysalides plus petites. La discussion a porté sur l'importance de ces comportements sur les relations de ces parasitoïdes avec leurs hôtes.

     

Genetic heterogeneity of insulin-dependent (type I) diabetes mellitus: evidence from a study of extended haplotypes

Two hundred subjects with insulin-dependent (type I) diabetes mellitus (IDDM) were typed for HLA-B, HLA-DR, and properdin factor B (Bf). HLA and Bf antigen and haplotype frequencies in subjects were compared with control frequencies derived from the 8th HLA Workshop. Frequencies of extended haplotypes (defined by B-Bf-DR alleles on a chromosome) were also contrasted with control frequencies. Significant positive associations between IDDM and HLA-B8, DR3, DR4, BfS, and BfF1 were confirmed, as were significant negative associations between IDDM and HLA-B7, DR2, DR5, DR7, and BfF. One haplotype (B7-BfS-DR2) exhibited significant negative association, while five haplotypes (B8-BfS-DR3, B8-BfS-DR4, B15-BfS-DR4, B18-BfF1-DR3, and B40-BfS-DR4) exhibited significant positive associations with IDDM. In this sample, 64% of all probands carried at least one of the high-risk haplotypes. In conclusion, the occurrence of five "high-risk" haplotypes associated with IDDM provides evidence for previously undocumented genetic heterogeneity and suggests that possibly more than two HLA-region genes may be involved in IDDM susceptibility.     

Age,area, and acheiropody

Summary Analysis of the geographic distribution of acheiropody suggests spread from São Paulo along the São Francisco valley at a rate consistent with current parent-offspring distribution and 20 generations of gene flow.PGL No. 233. This work was supported by Grants GM 17173 from the U.S. National Institutes of Health and Biologicas 79/0482 from São Paulo Research Foundation (FAPESP).     

Biological and cultural determinants of immunoglobulin levels in a Brazilian population with Chagas' disease

Summary Under a general model the genetic heritability is 0.33 for IgA, 0.34 for IgG and 0.12 for IgM, in a Brazilian population with Chagas' disease. Cultural heritability is much smaller. The analyses suggest that, with respect to family resemblance for immunoglobulins, there is no discrepancy between this sample and those from healthy populations reanalyzed recently (Barbosa et al. 1981).This work was supported by Grants 79/0482 FAPESP (Brazil), 77/2222.1392 CNPq (Brazil) and GM 17173 (Hawaii) with collaboration of the Fundação Instituto Osvaldo Cruz (Bambui, MG). Partly supported by NIH Grants GM 24941 and GM 28719.