Improving virus production through quasispecies genomic selection and molecular breeding

Abstract This chapter summarizes the current understanding of the response of wheat to waterlogging stress, the genetic control of uptake and transport of macro- and micronutrients, and the QTLs and genes associated with tolerance mechanisms. Potential targets for molecular breeding through marker-assisted selection and the potential for genomic selection are discussed in order to provide a better understanding of the biology and genes underlying soil waterlogging tolerance, as well as clarity and direction for breeders for future molecular breeding targets to expedite cultivar development.

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Molecular breeding for resilience in maize - A review

Journal of Applied and Natural Science ◽

10.31018/jans.v7i2.731 ◽

2015 ◽

Vol 7 (2) ◽

pp. 1057-1063

Author(s):

Asima Gazal ◽

Z. A. Dar ◽

A. A. Lone ◽

I. Abidi ◽

G. Ali

Keyword(s):

Genomic Selection ◽

Complex Traits ◽

Marker Assisted Selection ◽

Molecular Breeding ◽

Recurrent Selection ◽

Selection Marker ◽

Maize Breeding ◽

Time Duration ◽

Breeding Populations ◽

Breeding Research

Abiotic and biotic constraints have widespread yield reducing effects on maize and should receive high priority for maize breeding research. Molecular Breeding offers opportunities for plant breeders to develop cultivars with resilience to such diseases with precision and in less time duration. The term molecular breeding is used to describe several modern breeding strategies, including marker-assisted selection, marker-assisted backcrossing, marker-assisted recurrent selection and genomic selection. Recent advances in maize breeding research have made it possible to identify and map precisely many genes associated with DNA markers which include genes governing resistance to biotic stresses and genes responsible for tolerance to abiotic stresses. Marker assisted selection (MAS) allows monitoring the presence, absence of these genes in breeding populations whereas marker assisted backcross breeding effectively integrates major genes or quantitative trait loci (QTL) with large effect into widely grown adapted varieties. For complex traits where multiple QTLs control the expression, marker assisted recurrent selection (MARS) and genomic selection (GS) are employed to increase precision and to reduce cost of phenotyping and time duration. The biparental mapping populations used in QTL studies in MAS do not readily translate to breeding applications and the statistical methods used to identify target loci and implement MAS have been inadequate for improving polygenic traits controlled by many loci of small effect. Application of GS to breeding populations using high marker densities is emerging as a solution to both of these deficiencies. Hence, molecular breeding approaches offers ample opportunities for developing stress resilient and high-yielding maize cultivars.

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Stimulated Virus Production in Vinblastine and Cytochalasin-Induced Multinucleate Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100067923 ◽

1970 ◽

Vol 28 ◽

pp. 186-187

Author(s):

Krishan Awtar

Keyword(s):

Cell Division ◽

Normal Cell ◽

Virus Production ◽

Multinucleate Cells ◽

Daughter Cells ◽

Cell Divisions ◽

Nuclear Membranes ◽

Division 2 ◽

Vinblastine Sulfate

Exposure of cells to low sublethal but mitosis-arresting doses of vinblastine sulfate (Velban) results in the initial arrest of cells in mitosis followed by their subsequent return to an “interphase“-like stage. A large number of these cells reform their nuclear membranes and form large multimicronucleated cells, some containing as many as 25 or more micronuclei (1). Formation of large multinucleate cells is also caused by cytochalasin, by causing the fusion of daughter cells at the end of an otherwise .normal cell division (2). By the repetition of this process through subsequent cell divisions, large cells with 6 or more nuclei are formed.

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Ultrastructural observations of human monocytes infected with HIV-1

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084843 ◽

1991 ◽

Vol 49 ◽

pp. 108-109

Author(s):

James K. Koehler ◽

Steven G. Reed ◽

Joao S. Silva

Keyword(s):

Gradient Centrifugation ◽

Virus Production ◽

Human Monocyte ◽

Red Cross ◽

Human Monocytes ◽

Blood Monocytes ◽

Hiv Replication ◽

Electron Microscopic ◽

Ultrastructural Studies ◽

Hiv 1

As part of a larger study involving the co-infection of human monocyte cultures with HIV and protozoan parasites, electron microscopic observations were made on the course of HIV replication and infection in these cells. Although several ultrastructural studies of the cytopathology associated with HIV infection have appeared, few studies have shown the details of virus production in “normal,” human monocytes/macrophages, one of the natural targets of the virus, and suspected of being a locus of quiescent virus during its long latent period. In this report, we detail some of the interactions of developing virons with the membranes and organelles of the monocyte host.Peripheral blood monocytes were prepared from buffy coats (Portland Red Cross) by Percoll gradient centrifugation, followed by adherence to cover slips. 90-95% pure monocytes were cultured in RPMI with 5% non-activated human AB serum for four days and infected with 100 TCID50/ml of HIV-1 for four hours, washed and incubated in fresh medium for 14 days.

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Aberrant Type C Virus Production in a Cell Line Derived from Balb/3T3

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100094693 ◽

1972 ◽

Vol 30 ◽

pp. 286-287

Author(s):

N. Savage ◽

A. Hackett

Keyword(s):

Electron Microscopy ◽

Cell Line ◽

Leukemia Virus ◽

Morphological Characteristics ◽

Virus Production ◽

Oncogenic Viruses ◽

Endogenous Virus ◽

Virus Particles ◽

Moloney Leukemia Virus ◽

A Cell

A cell line, UC1-B, which was derived from Balb/3T3 cells, maintains the same morphological characteristics of the non-transformed parental culture, and shows no evidence of spontaneous virus production. Survey by electron microscopy shows that the cell line consists of spindle-shaped cells with no unusual features and no endogenous virus particles.UC1-B cells respond to Moloney leukemia virus (MLV) infection by a change in morphology and growth pattern which is typical of cells transformed by sarcoma virus. Electron microscopy shows that the cells are now variable in shape (rounded, rhomboid, and spindle), and each cell type has some microvilli. Virtually all (90%) of the cells show virus particles developing at the cell surface and within the cytoplasm. Maturing viruses, typical of the oncogenic viruses, are found along with atypical tubular forms in the same cell.

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