scholarly journals A semi-automatic technique for conducting many bacterial matings concurrently

1971 ◽  
Vol 17 (3) ◽  
pp. 261-266 ◽  
Author(s):  
Mark Achtman
Keyword(s):  
Mating Efficiency ◽  
Automatic Technique

SUMMARYA technique using microserological equipment is described whereby up to 144 quantitative interrupted bacterial matings may be performed concurrently. The technique is easy to use, accurate and reproducible, and eliminates the need for agar plates. However, it is only suitable for 40–42 °C matings and mating efficiency is approximately threefold lower than in test tubes.

scholarly journals A Nucleolar Protein That Affects Mating Efficiency in Saccharomyces cerevisiae by Altering the Morphological Response to Pheromone

Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 795-805
Author(s):  
Jinah Kim ◽  
Jeanne P Hirsch
Keyword(s):  
Growth Regulation ◽  
Subcellular Location ◽  
Null Alleles ◽  
Temperature Sensitive ◽  
Gene Products ◽  
Morphological Response ◽  
Mating Efficiency ◽  
Yeast Genes ◽  
Transcriptional Induction ◽  
In Cells

Abstract SSF1 and SSF2 are redundant essential yeast genes that, when overexpressed, increase the mating efficiency of cells containing a defective Ste4p Gβ subunit. To identify the precise function of these genes in mating, different responses to pheromone were assayed in cells that either lacked or overexpressed SSF gene products. Cells containing null alleles of both SSF1 and SSF2 displayed the normal transcriptional induction response to pheromone but were unable to form mating projections. Overexpression of SSF1 conferred the ability to form mating projections on cells containing a temperature-sensitive STE4 allele, but had only a small effect on transcriptional induction. SSF1 overexpression preferentially increased the mating efficiency of a strain containing a null allele of SPA2, a gene that functions specifically in cell morphology. To investigate whether Ssf1p plays a direct physical role in mating projection formation, its subcellular location was determined. An Ssf1p-GFP fusion was found to localize to the nucleolus, implying that the role of SSF gene products in projection formation is indirect. The region of Ssf1p-GFP localization in cells undergoing projection formation was larger and more diffuse, and was often present in a specific orientation with respect to the projection. Although the function of Ssf1p appears to originate in the nucleus, it is likely that it ultimately acts on one or more of the proteins that is directly involved in the morphological response to pheromone. Because many of the proteins required for projection formation during mating are also required for bud formation during vegetative growth, regulation of the activity or amount of one or more of these proteins by Ssf1p could explain its role in both mating and dividing cells.

Neuropeptide signalling shapes feeding and reproductive behaviours in male C. elegans

2021 ◽  
Author(s):  
Matthew J Gadenne ◽  
Iris Hardege ◽  
Djordji Suleski ◽  
Paris Jaggers ◽  
Isabel Beets ◽  
...  
Keyword(s):  
Synaptic Connectivity ◽  
Male Mating ◽  
Sexually Dimorphic ◽  
C Elegans ◽  
Mating Efficiency ◽  
Sexually Dimorphic Expression ◽  
Pharyngeal Pumping ◽  
Insight Into ◽  
Feeding Behaviours ◽  
Dimorphic Expression

Sexual dimorphism occurs where different sexes of the same species display differences in characteristics not limited to reproduction. For the nematode Caenorhabditis elegans, in which the complete neuroanatomy has been solved for both hermaphrodites and males, sexually dimorphic features have been observed both in terms of the number of neurons and in synaptic connectivity. In addition, male behaviours, such as food-leaving to prioritise searching for mates, have been attributed to neuropeptides released from sex-shared or sex-specific neurons. In this study, we show that the lury-1 neuropeptide gene shows a sexually dimorphic expression pattern; being expressed in pharyngeal neurons in both sexes but displaying additional expression in tail neurons only in the male. We also show that lury-1 mutant animals show sex differences in feeding behaviours, with pharyngeal pumping elevated in hermaphrodites but reduced in males. LURY-1 also modulates male mating efficiency, influencing motor events during contact with a hermaphrodite. Our findings indicate sex-specific roles of this peptide in feeding and reproduction in C. elegans, providing further insight into neuromodulatory control of sexually dimorphic behaviours.

scholarly journals Deletion of ptn1, a PTEN/TEP1 Orthologue, in Ustilago maydis Reduces Pathogenicity and Teliospore Development

2018 ◽  
Vol 5 (1) ◽  
pp. 1 ◽  
Author(s):  
Lalu Vijayakrishnapillai ◽  
John Desmarais ◽  
Michael Groeschen ◽  
Michael Perlin
Keyword(s):  
Defense Mechanisms ◽  
Developmental Process ◽  
Signal Transduction Pathway ◽  
Ustilago Maydis ◽  
Suppressor Gene ◽  
Tumor Formation ◽  
Proliferation And Apoptosis ◽  
Mating Efficiency ◽  
Percent Germination

The PTEN/PI3K/mTOR signal transduction pathway is involved in the regulation of biological processes such as metabolism, cell growth, cell proliferation, and apoptosis. This pathway has been extensively studied in mammals, leading to the conclusion that PTEN is a major tumor suppressor gene. PTEN orthologues have been characterized in a variety of organisms, both vertebrates and non-vertebrates, and studies of the associated PTEN/PI3K/mTOR pathway indicate that it is widely conserved. Studies in fungal systems indicated a role of PTEN in fungal defense mechanisms in Candida albicans, and in the developmental process of sporulation in Saccharomyces cerevisiae. The present study was aimed at investigating the role of the PTEN ortholog, ptn1, in Ustilago maydis, the pathogen of maize. U. maydis ptn1 mutant strains where ptn1 gene is deleted or overexpressed were examined for phenotypes associate with mating, virulence and spore formation. While the overexpression of ptn1 had no substantial effects on virulence, ptn1 deletion strains showed slight reductions in mating efficiency and significant reductions in virulence; tumor formation on stem and/or leaves were severely reduced. Moreover, tumors, when present, had significantly lower levels of mature teliospores, and the percent germination of such spores was similarly reduced. Thus, ptn1 is required for these important aspects of virulence in this fungus.

scholarly journals Biometric Foetal Contour Extraction using Hybrid Level Set

2020 ◽  
Author(s):  
Rachana Jaiswal ◽  
Srikant Satarkar
Keyword(s):  
Feature Extraction ◽  
Level Set ◽  
Medical Images ◽  
Traditional Approach ◽  
Ultrasound Images ◽  
Contour Extraction ◽  
Processing Technologies ◽  
Biometric Measurements ◽  
Ultrasonic Images ◽  
Automatic Technique

In medical imaging, accurate anatomical structure extraction is important for diagnosis and therapeutic interventional planning. So, for easier, quicker and accurate diagnosis of medical images, image processing technologies may be employed in analysis and feature extraction of medical images. In this paper, some modifications to level set algorithm are made and modified algorithm is used for extracting contour of foetal objects in an image. The proposed approach is applied on foetal ultrasound images. In traditional approach, foetal parameters are extracted manually from ultrasound images. Due to lack of consistency and accuracy of manual measurements, an automatic technique is highly desirable to obtain foetal biometric measurements. This proposed approach is based on global & local region information for foetal contour extraction from ultrasonic images. The primary goal of this research is to provide a new methodology to aid the analysis and feature extraction from foetal images.

scholarly journals REDUCED REPRODUCTIVE SUCCESS FOR A CONDITIONING MUTANT IN EXPERIMENTAL POPULATIONS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1985 ◽  
Vol 111 (4) ◽  
pp. 795-804
Author(s):  
Donald A Gailey ◽  
Jeffrey C Hall ◽  
Richard W Siegel
Keyword(s):  
Drosophila Melanogaster ◽  
Reproductive Success ◽  
Learning And Memory ◽  
Courtship Behavior ◽  
Virgin Female ◽  
Mating Advantage ◽  
Mating Efficiency ◽  
Normal Males ◽  
Time Required ◽  
Dependent Modification

ABSTRACT Male Drosophila melanogaster that have courted newly-emerged males can modify their subsequent courtship behavior to avoid further courtship with immature males for up to 6 hr (previously reported). Here, it was hypothesized that such an experience-dependent modification would afford a mating advantage to normal males over males that carried a mutation that affects learning and memory. Coisogenic lines were constructed which varied at the dunce gene (dnc  + and dnc  M14 alleles) in order to test this hypothesis. Whether previously experienced with immature males or not, dnc  + and dnc  M14 males were indistinguishable in their response and mating efficiency when individually paired with virgin females. However, courtship performance of dnc  + and dnc  M14 males was different if they were first experienced with immature males and were then individually tested in an artificial population of nine immature males and one virgin female. In this situation, dnc  + males spent much less time in courtship with immature males and achieved copulation in one-third the time required for dnc  M14 males. As a control, the behavior and mating efficiency of courtship-naive dnc  + and dnc  M14 males in the artificial population was indistinguishable. In competition for a single virgin female, experienced dnc  M14 males showed a slight mating advantage over experienced dnc  + males. But when competition by experienced males for a single virgin female took place in the presence of nine immature males, dnc  + males were the successful maters in three-fourths of the trials.

scholarly journals A and alpha supernatant pretreatment of Saccharomyces cerevisiae cells affects both the kinetics and efficiency of mating.

1982 ◽  
Vol 2 (8) ◽  
pp. 897-903 ◽  
Author(s):  
E P Sena
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Fusion ◽  
Large Scale ◽  
Culture Supernatant ◽  
Treatment Procedure ◽  
Logarithmic Growth Phase ◽  
Future Studies ◽  
Mating Efficiency ◽  
Potential Applications ◽  
Logarithmic Growth

The effects of culture supernatant treatment on subsequent matings between pretreated a and alpha Saccharomyces cerevisiae cells were studied. For each experiment, pairs of a and alpha [rho+] or [rho- rho0] cells in the logarithmic growth phase in defined minimal medium were pretreated for a total of 15 min (by exchanging their cell-free supernatants or by mixing samples of a and alpha cell cultures) and then mated in defined minimal (YNB) or enriched (YEP) liquid medium. All pretreated cells, regardless of treatment procedure, initiated cell fusion 15 to 35 min faster than did their nontreated counterparts. In all cases, pretreated cells mated 8 to 20% more efficiently than did nonpretreated ones. Regardless of the strains, the hierarchy of mating efficiency was always treated YEP greater than untreated YEP greater than treated YNB greater than untreated YNB. The cell fusion kinetics in alpha [rho+] X a [rho-] crosses were most affected by pretreatment (delta 30 to 35 min), whereas [rho+] X [rho+] crosses were least affected (delta 15 min). These results are discussed in relation to the functions known for a and alpha pheromones. The successful pretreatment regimes were used to design new rapid and efficient techniques for mating YNB-grown log-phase cells in either YNB or YEP liquid media. These techniques can be used for small- or large-scale mating, and because of their inherent media flexibility, they have many potential applications to future studies on mating-specific or intrazygotic phenomena.

AN IMPROVED RANDOM WALK SEGMENTATION ON THE LUNG NODULES

2013 ◽  
Vol 06 (06) ◽  
pp. 1350043 ◽  
Author(s):  
LI GUO ◽  
YUNTING ZHANG ◽  
ZEWEI ZHANG ◽  
DONGYUE LI ◽  
YING LI
Keyword(s):  
Random Walk ◽  
Lung Nodule ◽  
Texture Feature ◽  
Ellipse Fitting ◽  
Lung Nodule Detection ◽  
Random Walk Algorithm ◽  
Fitting Algorithm ◽  
Nodule Detection ◽  
Walk Algorithm ◽  
Automatic Technique

In this paper, we proposed a semi-automatic technique with a marker indicating the target to locate and segment nodules. For the lung nodule detection, we develop a Gabor texture feature by FCM (Fuzzy C Means) segmentation. Given a marker indicating a rough location of the nodules, a decision process is followed by applying an ellipse fitting algorithm. From the ellipse mask, the foreground and background seeds for the random walk segmentation can be automatically obtained. Finally, the edge of the nodules is obtained by the random walk algorithm. The feasibility and effectiveness of the proposed method are evaluated with the various types of the nodules to identify the edges, so that it can be used to locate the nodule edge and its growth rate.

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