Nest Architecture and Colony Growth of Atta bisphaerica Grass-Cutting Ants

Atta grass-cutting ants (Formicidae: Myrmicinae: Attini) are found in the Cerrado biome and build giant nests with hundreds or thousands of large chambers. We assessed for Atta bisphaerica grass-cutting ants whether the total volume of fungus chambers and other nest parameters grow at close or similar proportions to worker numbers in the colony. Data on fungus garden biomass, population, external area, number of entrance holes, number of fungus chambers, total fungus chambers volume, and nest depth were obtained during colony growth/nest development. Our results reveal that the fungus garden biomass, external area, and total fungus chamber volume increased at rates similar to the increase in the number of workers. The total volume of chambers, and external area increased at a similar proportion to the increase in number of workers, probably due to the fungus garden allocation needs of the colony. The number of fungus chambers, number of entrance holes, and nest depth increased less than 4-fold for every 10-fold increase in the worker number. In addition, the height of the fungus chambers increased as the width increased, a pattern not observed for tunnel height and length, and the chamber volume increased according to worker number. Thus, this study demonstrates for A. bisphaerica that nest development in terms of chamber volume is similar to the increase in number of colony workers, and this contributes to a better understanding of Atta nest architecture.

Download Full-text

Discovering the Giant Nest Architecture of Grass-Cutting Ants, Atta capiguara (Hymenoptera, Formicidae)

10.20944/preprints201702.0027.v1 ◽

2017 ◽

Author(s):

Luiz Carlos Forti ◽

Ana Paula Protti de Andrade ◽

Roberto da Silva Camargo ◽

Nadia Caldato ◽

Aldenise Alves Moreira

Keyword(s):

Main Part ◽

Ground Level ◽

Conic Section ◽

Nest Architecture ◽

Cerrado Biome ◽

Loose Soil ◽

Internal Structures ◽

Length Width ◽

Typical Shape

Atta capiguara is a grass-cutting ant species frequently found in Cerrado biome. However, little is known about the giant nest architecture of this ant. In this study, we investigated the architecture of three A. capiguara nests from the fragment of cerrado in Botucatu, São Paulo, Brazil. Casts were made of the nests by filling them with cement to permit better visualization of internal structures such as chambers and tunnels. After excavation, the depth and dimensions (length, width, and height) of the chambers were measured. The results showed the typical shape of Atta capiguara nests consisting of mounds of loose soil with unique features resembling a conic section. The fungus chambers were found outside the apparent main part of the nest and were spaced apart and distributed laterally at ground level. The waste chambers were located beneath the largest mound of loose soil. Both the fungus and waste chambers exhibited a sectoral distribution. Our study contributes to a better understanding of the so far unknown nest architecture of the grass-cutting ant A. capiguara.

Download Full-text

Leaf-Cutter Ant Fungus Gardens Are Biphasic Mixed Microbial Bioreactors That Convert Plant Biomass to Polyols with Biotechnological Applications

Applied and Environmental Microbiology ◽

10.1128/aem.00046-15 ◽

2015 ◽

Vol 81 (13) ◽

pp. 4525-4535 ◽

Cited By ~ 8

Author(s):

Alexandre F. Somera ◽

Adriel M. Lima ◽

Álvaro J. dos Santos-Neto ◽

Fernando M. Lanças ◽

Maurício Bacci

Keyword(s):

Microbial Growth ◽

Plant Biomass ◽

Starch Degradation ◽

Fungus Garden ◽

Plant Resources ◽

Plant Polysaccharides ◽

Content Type ◽

Plant Matter ◽

Ant Fungus ◽

Garden Biomass

ABSTRACTLeaf-cutter ants use plant matter to culture the obligate mutualistic basidiomyceteLeucoagaricusgongylophorus. This fungus mediates ant nutrition on plant resources. Furthermore, other microbes living in the fungus garden might also contribute to plant digestion. The fungus garden comprises a young sector with recently incorporated leaf fragments and an old sector with partially digested plant matter. Here, we show that the young and old sectors of the grass-cutterAttabisphaericafungus garden operate as a biphasic solid-state mixed fermenting system. An initial plant digestion phase occurred in the young sector in the fungus garden periphery, with prevailing hemicellulose and starch degradation into arabinose, mannose, xylose, and glucose. These products support fast microbial growth but were mostly converted into four polyols. Three polyols, mannitol, arabitol, and inositol, were secreted byL.gongylophorus, and a fourth polyol, sorbitol, was likely secreted by another, unidentified, microbe. A second plant digestion phase occurred in the old sector, located in the fungus garden core, comprising stocks of microbial biomass growing slowly on monosaccharides and polyols. This biphasic operation was efficient in mediating symbiotic nutrition on plant matter: the microbes, accounting for 4% of the fungus garden biomass, converted plant matter biomass into monosaccharides and polyols, which were completely consumed by the resident ants and microbes. However, when consumption was inhibited through laboratory manipulation, most of the plant polysaccharides were degraded, products rapidly accumulated, and yields could be preferentially switched between polyols and monosaccharides. This feature might be useful in biotechnology.

Download Full-text

TISSUE CULTURE OF MICE KIDNEYS FOR THE TOXICITY EVALUATION OF SOME CYTOSTATICS

Periódico Tchê Química ◽

10.52571/ptq.v16.n33.2019.918_periodico33_pgs_903_910.pdf ◽

2019 ◽

Vol 16 (33) ◽

pp. 903-910

Author(s):

V. P. PASHCHENKO ◽

N. A. NAZARENKO ◽

L. E. GROMOVA ◽

G. S. PASHCHENKO ◽

M. Y. NAZARENKO

Keyword(s):

Tissue Culture ◽

Fold Increase ◽

Colony Growth ◽

Renal Tissue ◽

Tissue Cultures ◽

Toxicity Evaluation ◽

Oncologic Diseases ◽

Different Doses ◽

Millipore Filters

The rationale for the present study is explained by a high risk of the development of side effects, including nephrotoxic, in patients that receive the treatment with cytostatics bleocin, lastet, and cisplatin for oncologic diseases. The present article focuses on the evaluation of the toxicity of the mentioned drugs. The method of plasma-free renal tissue cultures in mice on the perforated millipore filters was used. The identification of the toxicity of different doses of the drugs was performed by the comparison of the areas of the grown colonies. The authors presented the data that the inhibition of the growth of renal tissue cultures (by 50%) required a 4.3-fold increase in the dose of lastet in comparison with bleocin. The inhibition of the tissue culture colony growth with cisplatin by 85% was registered in the dose of the drug that corresponded to a 3% solution. The materials of the article have significant practical value because a rational indication of cytostatics bleocin, lastet, and cisplatin with regard to their nephrotoxic effect will allow the specialists to improve the treatment outcome and will contribute to the improvement of the quality of life of patients.

Download Full-text

CRLF2 Overexpression Demonstrates Enhanced Leukemogenicity in Down Syndrome Hematopoietic Cells

Blood ◽

10.1182/blood.v128.22.2708.2708 ◽

2016 ◽

Vol 128 (22) ◽

pp. 2708-2708

Author(s):

Jacob J. Junco ◽

Shan Liang ◽

Vishal Gokani ◽

Vincent Ulysses Gant ◽

Jaime Munoz ◽

...

Keyword(s):

Down Syndrome ◽

B Cells ◽

B Cell ◽

Fold Increase ◽

Colony Growth ◽

Genetic Alterations ◽

Chromosome 21 ◽

Lower Percentage ◽

Hematopoietic Stem ◽

B Lymphoid

Abstract Introduction: Children with Down syndrome (DS) are 10-20 times more likely than children without DS to develop acute lymphoblastic leukemia (ALL), and they demonstrate a distinctive spectrum of genetic alterations. Approximately 50% of DS-ALL cases demonstrate CRLF2 rearrangements (CRLF2-R), an approximately 10-fold higher frequency than in non-DS ALL. We sought to identify the functional basis for the increased incidence of ALL, and specifically CRLF2-R ALL, in children with DS. Methods: We created retroviral vectors which induce overexpression of CRLF2 and green fluorescent protein (GFP) for transduction into bone marrow (BM) cells isolated from the Dp16(1)Yey (Dp16) mouse model of DS, which is trisomic for the approximately 115 human chromosome 21 gene orthologs present on mouse chromosome 16. Transduced BM cells from Dp16 and wild-type (WT) control mice were co-cultured with OP9 stromal cells for one week to promote B-lymphoid lineage development, and then characterized by flow cytometric Hardy fraction analysis, or grown in B-lymphoid-promoting methylcellulose medium for colony growth assays. Results: We achieved efficient transduction (80-95%) of Dp16 and WT BM enriched for hematopoietic stem cells (HSCs) with CRLF2-GFP+ and control GFP+ viruses. Following OP9 co-culture, transduced HSCs were characterized by Hardy fraction analysis. CRLF2-GFP+ Dp16 lymphoid cells demonstrated significantly higher percentages of immature Fraction A (pre-pro-B) cells compared with GFP+ Dp16 cells (39.9% vs 15.7%, p=0.004, Fig. 1A). This CRLF2-GFP-induced immature immunophenotype was more pronounced in Dp16 versus WT HSCs, with a significantly higher percentage of Fraction A cells (39.9% in Dp16 vs 24.0% in WT, p=0.0002) and a significantly lower percentage of more mature Fraction B (pro-B) cells (24.3% in Dp16 vs 49.1% in WT, p=0.02, Fig. 1A,B). In methylcellulose colony assays, CRLF2-GFP+ Dp16 cells yielded a 36-fold increase in B cell colonies compared to GFP+ Dp16 cells (Fig 1C). Again, the effect of CRLF2 transduction was magnified in the Dp16 versus WT background. CRLF2-GFP+ WT cells demonstrated only a 2.9-fold increase in B cell colonies (Fig 1C). Conclusions: Here we demonstrate that CRLF2 overexpression results in a more immature B-lineage immunophenotype and increased lymphoid colony growth in vitro, and that these effects are significantly greater in a murine DS versus WT genetic background. Experiments to investigate the pathways involved and to evaluate these effects in vivo are ongoing. This work provides functional evidence of the enhanced leukemogenicity of CRLF2 overexpression in DS-ALL, and creates a tractable model system for additional future genetic studies. Disclosures No relevant conflicts of interest to declare.

Download Full-text

First Report of Reduced Sensitivity to a QoI Fungicide in Apple Scab (Venturia inaequalis) in Virginia and Maryland

Plant Disease ◽

10.1094/pdis-03-12-0246-pdn ◽

2012 ◽

Vol 96 (9) ◽

pp. 1376-1376 ◽

Cited By ~ 1

Author(s):

S. C. Marine ◽

D. G. Schmale ◽

K. S. Yoder

Keyword(s):

Venturia Inaequalis ◽

Apple Scab ◽

Fold Increase ◽

Colony Growth ◽

The United States ◽

Current Season ◽

First Report ◽

Development Of Resistance ◽

Health Progress ◽

The Difference

Apple scab caused by Venturia inaequalis (Cooke) Winter continues to be a significant concern for apple growers in Virginia and Maryland. Management of scab has relied on foliar fungicides including strobilurins (QoIs) such as trifloxystrobin (TFX). In recent years, populations of V. inaequalis with reduced sensitivity to the QoIs have been reported in other apple-growing regions of the United States (1,2). Although QoIs generally remain effective in the mid-Atlantic, concerns about the development of resistance in some Virginia and Maryland orchards prompted this study. Twenty-five isolates of V. inaequalis were obtained from scabby leaves from commercial and experimental orchards in Virginia in 2010 (n = 6) and 2011 (n = 14) and from a commercial orchard in Maryland (n = 5) in 2011. Orchards had previously been treated with QoI or sterol-inhibiting (SI) fungicides. Isolates of V. inaequalis were grown on potato dextrose agar (PDA) amended with 0, 0.1, or 1.0 μg ml–1 TFX with 100 μg ml–1 salicylhydroxamic acid (SHAM) and incubated at 19°C. Colony growth was measured weekly for 4 weeks. To account for the SI use at some orchards, isolates of V. inaequalis were also evaluated on PDA amended with 0, 0.5, or 1.0 μg ml–1 myclobutanil. Fungicide sensitivities were expressed as a percentage of the difference in colony growth using a discriminatory dose of 1.0 μg ml–1 TFX with SHAM or 1.0 μg ml–1 myclobutanil at 28 days. Isolates with <25% growth suppression (GS) were classified as fully resistant, whereas those with >70% GS were classified as sensitive. Isolates with 25 to 70% GS were classified as partially resistant. Effective concentration (EC50) values (TFX concentration inhibiting colony growth by 50%) were also calculated for a subset of fully resistant and sensitive isolates. Of the 25 isolates tested, six were fully resistant to TFX (mean EC50 value greater than 10.0 μg ml–1) and 10 were sensitive (mean EC50 value of 0.04 μg ml–1 ± 0.05 μg ml–1). Nine isolates were classified as partially resistant. Some isolates showed more than a 200-fold increase in resistance to TFX, and one isolate grew almost as well on 10.0 μg ml–1 TFX as on the unamended control (GS of 3%). Current-season use of QoIs on isolate source trees was significantly associated with a lack of sensitivity Ç2 (1) = 3.72 (P < 0.06). All six fully resistant isolates originated from QoI-treated commercial orchards, which had shown control failures. Seven of 10 isolates sensitive to QoIs originated from trees that had been treated with SIs during the isolation year. Resistance to myclobutanil was not significantly associated with resistance to TFX Ç2 (1) = 1.220 (P < 0.5), and only one isolate was resistant (i.e. >25% GS) to both. Despite the long history of QoI use at the experimental orchards, no isolates fully resistant to TFX were identified there. To our knowledge, this is the first report of V. inaequalis isolates with resistance to TFX in Virginia and Maryland. Since SI resistance has been documented in Virginia (3) and resistance to both the SI and QoI chemical classes is a concern in the mid-Atlantic region (4), tank-mixing or alternating QoIs with broad-spectrum fungicides with different modes of action is recommended. References: (1). K. M. Cox et al. Phythopathology 99:S25, 2009. (2). K. E. Lesniak et al. Plant Dis. 95:927, 2011. (3) S. C. Marine et al. Plant Health Progress. doi:10.1094/PHP-2007-1113-01-RS, 2007. (4) E. E. Pfeufer and H. K. Ngugi. Phytopathology 102:272, 2012.

Download Full-text

Analysis of 2D and 3D defects associated with precipitation of Cu in silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010008866x ◽

1991 ◽

Vol 49 ◽

pp. 870-871

Author(s):

P.M. Rice ◽

MJ. Kim ◽

R.W. Carpenter

Keyword(s):

Colony Growth ◽

Dark Field ◽

Dark Side ◽

Silicide Phase ◽

Strain Fields ◽

Near Surface ◽

Unknown Composition ◽

Secondary Precipitates ◽

20 Nm ◽

2D And 3D

Extrinsic gettering of Cu on near-surface dislocations in Si has been the topic of recent investigation. It was shown that the Cu precipitated hetergeneously on dislocations as Cu silicide along with voids, and also with a secondary planar precipitate of unknown composition. Here we report the results of investigations of the sense of the strain fields about the large (~100 nm) silicide precipitates, and further analysis of the small (~10-20 nm) planar precipitates.Numerous dark field images were analyzed in accordance with Ashby and Brown's criteria for determining the sense of the strain fields about precipitates. While the situation is complicated by the presence of dislocations and secondary precipitates, micrographs like those shown in Fig. 1(a) and 1(b) tend to show anomalously wide strain fields with the dark side on the side of negative g, indicating the strain fields about the silicide precipitates are vacancy in nature. This is in conflict with information reported on the η'' phase (the Cu silicide phase presumed to precipitate within the bulk) whose interstitial strain field is considered responsible for the interstitial Si atoms which cause the bounding dislocation to expand during star colony growth.

Download Full-text

Detection of viruses by electron microscopy: Increased sensitivity by direct micro-ultracentrifugation of samples

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128821 ◽

1987 ◽

Vol 45 ◽

pp. 908-909

Author(s):

Alain R. Trudel ◽

M. Trudel

Keyword(s):

Electron Microscopy ◽

Fold Increase ◽

Observation Time ◽

Clinical Samples ◽

Maximum Speed ◽

Viral Particles ◽

Structural Details ◽

Latex Spheres ◽

Increased Sensitivity ◽

Size Of Particles

AirfugeR (Beckman) direct ultracentrifugation of viral samples on electron microscopy grids offers a rapid way to concentrate viral particles or subunits and facilitate their detection and study. Using the A-100 fixed angle rotor (30°) with a K factor of 19 at maximum speed (95 000 rpm), samples up to 240 μl can be prepared for electron microscopy observation in a few minutes: observation time is decreased and structural details are highlighted. Using latex spheres to calculate the increase in sensitivity compared to the inverted drop procedure, we obtained a 10 to 40 fold increase in sensitivity depending on the size of particles. This technique also permits quantification of viral particles in samples if an aliquot is mixed with latex spheres of known concentration.Direct ultracentrifugation for electron microscopy can be performed on laboratory samples such as gradient or column fractions, infected cell supernatant, or on clinical samples such as urine, tears, cephalo-rachidian liquid, etc..

Download Full-text

Advantages of Complementary Stereo Images as Viewed with the Low-Temperature Field-Emission SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100131206 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1314-1315

Author(s):

William P. Wergin ◽

Eric F. Erbe

Keyword(s):

Fold Increase ◽

Horizontal Displacement ◽

Three Dimensions ◽

Stereo Image ◽

Stereo Pair ◽

Sem Micrograph ◽

Left And Right ◽

The Common ◽

The Brain ◽

Pair Analysis

The eye-brain complex allows those of us with normal vision to perceive and evaluate our surroundings in three-dimensions (3-D). The principle factor that makes this possible is parallax - the horizontal displacement of objects that results from the independent views that the left and right eyes detect and simultaneously transmit to the brain for superimposition. The common SEM micrograph is a 2-D representation of a 3-D specimen. Depriving the brain of the 3-D view can lead to erroneous conclusions about the relative sizes, positions and convergence of structures within a specimen. In addition, Walter has suggested that the stereo image contains information equivalent to a two-fold increase in magnification over that found in a 2-D image. Because of these factors, stereo pair analysis should be routinely employed when studying specimens.Imaging complementary faces of a fractured specimen is a second method by which the topography of a specimen can be more accurately evaluated.

Download Full-text

Prevalence of Self-Reported Depression Symptoms and Perceived Anxiety Among Community-Dwelling U.S. Adults Reporting Tinnitus

Perspectives of the ASHA Special Interest Groups ◽

10.1044/2020_persp-19-00178 ◽

2020 ◽

Vol 5 (4) ◽

pp. 959-970

Author(s):

Kelly M. Reavis ◽

James A. Henry ◽

Lynn M. Marshall ◽

Kathleen F. Carlson

Keyword(s):

Mental Health ◽

Fold Increase ◽

Community Dwelling ◽

Self Report ◽

Depression Symptoms ◽

Community Based Interventions ◽

Data Set ◽

Health Distress ◽

Validated Questionnaire ◽

Mental Health Distress

Purpose The aim of this study was to examine the relationship between tinnitus and self-reported mental health distress, namely, depression symptoms and perceived anxiety, in adults who participated in the National Health and Nutrition Examinations Survey between 2009 and 2012. A secondary aim was to determine if a history of serving in the military modified the associations between tinnitus and mental health distress. Method This was a cross-sectional study design of a national data set that included 5,550 U.S. community-dwelling adults ages 20 years and older, 12.7% of whom were military Veterans. Bivariable and multivariable logistic regression was used to estimate the association between tinnitus and mental health distress. All measures were based on self-report. Tinnitus and perceived anxiety were each assessed using a single question. Depression symptoms were assessed using the Patient Health Questionnaire, a validated questionnaire. Multivariable regression models were adjusted for key demographic and health factors, including self-reported hearing ability. Results Prevalence of tinnitus was 15%. Compared to adults without tinnitus, adults with tinnitus had a 1.8-fold increase in depression symptoms and a 1.5-fold increase in perceived anxiety after adjusting for potential confounders. Military Veteran status did not modify these observed associations. Conclusions Findings revealed an association between tinnitus and both depression symptoms and perceived anxiety, independent of potential confounders, among both Veterans and non-Veterans. These results suggest, on a population level, that individuals with tinnitus have a greater burden of perceived mental health distress and may benefit from interdisciplinary health care, self-help, and community-based interventions. Supplemental Material https://doi.org/10.23641/asha.12568475

Download Full-text