scholarly journals Bacterial Growth in Milpa Polyculture and Monoculture Soils [Emory University]

2019 ◽  
Author(s):  
Kino Emmanuel Maravillas ◽  
Erika Diaz-Almeyda ◽  
Nicole Gerardo
Keyword(s):  
Indigenous Population ◽  
Cropping System ◽  
Antibiotic Activity ◽  
Bacterial Strains ◽  
Anasa Tristis ◽  
Squash Bug ◽  
Cucurbit Yellow Vine Disease ◽  
Emory University ◽  
Burkholderia Strain ◽  
Three Sisters

Polycultures, or multicrops, are groupings of plants that grow more prolifically when planted together as compared to when planted alone as monocultures. One of the best known and widely utilized polycultures is the milpa cropping system - the cultivation of maize, beans, and squash together as “the three sisters.” Milpa has been utilized by the indigenous population of Central America for millennia due to its consistent abundant harvests; today it remains a cornerstone of the region’s tradition, diet, and economic growth. Likely contributing to this legacy is the known association of polycultures and heightened resistance to disease, yet the mechanism underlying this relationship in milpa has largely been unexplored. To assess the health of farm soil exposed to milpa monocrops, bicrops, and multicrops, we measured the growth of two bacterial strains: a Burkholderia strain symbiotic of Anasa tristis (the squash bug, an agricultural pest) and a plant pathogenic Serratia strain that is the primary causal agent of cucurbit yellow vine disease (CYVD). We found that after one week in both the polyculture (corn, bean, and squash) soil and the corn monoculture soil, the growth of Burkholderia was significantly inhibited. However, in both corn & bean and bean & squash biculture soils, the growth of the strain was significantly enhanced. The growth of the Serratia strain did not yield any significant increase or decrease after one week in any milpa soil. We conclude that the cultivation of milpa in its polyculture configuration demonstrates antibiotic activity towards the Burkholderia strain SQ4A. Our investigation supports findings that certain multicrop systems are less susceptible to disease than monocultures possibly due to their greater microbial biomass; thus we can infer a higher amount of root exudates present in the soil, of which a substantial amount may be anti-microbials.

scholarly journals Diversity of Serratia marcescens Strains Associated with Cucurbit Yellow Vine Disease in Georgia

Plant Disease ◽  
2017 ◽  
Vol 101 (1) ◽  
pp. 129-136 ◽  
Author(s):  
K. R. Besler ◽  
E. L. Little
Keyword(s):  
Genetic Diversity ◽  
Serratia Marcescens ◽  
Housekeeping Genes ◽  
Ecological Niches ◽  
Anasa Tristis ◽  
Squash Bug ◽  
Cucurbit Yellow Vine Disease ◽  
Related Group ◽  
Polymerase Chain ◽  
Shared Genetic

Cucurbit yellow vine disease (CYVD), caused by the squash bug (Anasa tristis)-transmitted bacterium Serratia marcescens, was first identified in Oklahoma and Texas in 1988 and in Georgia in 2012. S. marcescens is a highly diverse species found in many ecological niches. In previous studies, CYVD strains of S. marcescens formed a closely related group separate from non-CYVD strains based on biological and molecular characterization techniques. Multilocus sequence analysis (MLSA) of six housekeeping genes and repetitive elements-based polymerase chain reaction (rep-PCR) using the BOX and ERIC primers were used to assess the genetic diversity of CYVD strains of S. marcescens collected in Georgia together with a strain from Texas and seven non-CYVD strains of S. marcescens. rep-PCR results revealed genetic diversity among CYVD strains while MLSA results showed a 100% similarity across the six loci for all but one of the CYVD strains, which differed at the icd locus by five polymorphisms. For both methods, CYVD strains clustered separately from nonplant-pathogenic S. marcescens strains and were most similar to a rice endophyte strain. One CYVD strain isolated from a squash bug shared genetic similarities with non-CYVD strains, and may be the result of a recombination event between CYVD and non-CYVD strains.

scholarly journals Serratia marcescens, a Phloem-Colonizing, Squash Bug -Transmitted Bacterium: Causal Agent of Cucurbit Yellow Vine Disease

Plant Disease ◽  
2003 ◽  
Vol 87 (8) ◽  
pp. 937-944 ◽  
Author(s):  
B. D. Bruton ◽  
F. Mitchell ◽  
J. Fletcher ◽  
S. D. Pair ◽  
A. Wayadande ◽  
...  
Keyword(s):  
Serratia Marcescens ◽  
Luria Bertani ◽  
Causal Agent ◽  
Anasa Tristis ◽  
Specific Pcr ◽  
Squash Bug ◽  
Cucurbit Yellow Vine Disease ◽  
Crown Tissue ◽  
Production Areas ◽  
Causal Bacterium

Cucurbit yellow vine disease (CYVD), which can inflict heavy losses to watermelon, pumpkin, cantaloupe, and squash in U.S. production areas from the midwest to northeastern states, causes phloem discoloration, foliar yellowing, wilting, and plant decline. Bacteria were cultured from the phloem of crown sections of symptomatic plants of Citrullus lanatas and Cucurbita pepo. Those bacteria testing positive in CYVD-specific polymerase chain reaction (PCR) were all gram negative and appeared morphologically identical, producing creamy white, smooth, entire, convex colonies on Luria-Bertani or nutrient agar. Characterized cucurbit-derived strains of Serratia marcescens were introduced into greenhouse-grown squash plants by puncture inoculation and into field-grown squash plants by enclosure with S. marcescens-fed squash bugs, Anasa tristis. Up to 60% of the bacteria-inoculated plants in the greenhouse and up to 17% of field plants caged with inoculative squash bugs developed phloem discoloration and tested positive for S. marcescens by CYVD-specific PCR. None of the controls developed phloem discoloration or tested positive by PCR. Of the diseased field plants, 12% (2 of 35) also yellowed, wilted, and collapsed, exhibiting full symptom development of CYVD. However, neither plant collapse nor decline was observed in the greenhouse-grown, puncture-inoculated plants. The morphology, growth habit, and PCR reaction of bacteria cultured from crown tissue of a subset of plants in each experimental group were indistinguishable from those of the inoculum bacteria. Evidence presented from our studies confirms that the squash bug can transmit S. marcescens, the CYVD causal bacterium. The S. marcescens-A. tristis relationship described here is the first instance in which the squash bug has been identified as a vector of a plant pathogen. Our experiments represent a completion of the steps of Koch's postulates, demonstrating that S. marcescens is the causal agent of CYVD and that the squash bug, A. tristis, is a vector of the pathogen.

Low pH reduces the activity of ceftolozane/tazobactam in human urine, but confirms current breakpoints for urinary tract infections

2019 ◽  
Vol 75 (3) ◽  
pp. 593-599 ◽  
Author(s):  
Alina Karoline Nussbaumer-Pröll ◽  
Sabine Eberl ◽  
Birgit Reiter ◽  
Thomas Stimpfl ◽  
Christoph Dorn ◽  
...  
Keyword(s):  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Human Urine ◽  
Negative Impact ◽  
Low Ph ◽  
Antibiotic Activity ◽  
Clinical Isolates ◽  
Acidic Ph ◽  
Bacterial Strains ◽  
Tract Infections

Abstract Background Acidic pH has been shown to impact the antibiotic activity of non-β-lactams in urine. Objectives To investigate the in vitro activity of ceftolozane/tazobactam compared with meropenem at different pH settings in urine. Methods We determined the MICs for 30 clinical isolates of Escherichia coli, 25 clinical isolates of Klebsiella pneumoniae and 24 clinical isolates of Proteus mirabilis in pooled human urine and standard growth medium at pH 5 and 7. Time–kill curves were produced for one representative clinical isolate of tested bacterial strains in urine at pH 5, 6 and 7 for both antibiotics at concentrations above and below the MIC. HPLC analysis of the stability of ceftolozane/tazobactam and meropenem was performed at different pH values. Results The median MICs of both antibiotics were up to 8-fold higher at pH 5 than at pH 7. Bacterial growth of E. coli was not impacted by pH, while for K. pneumoniae and P. mirabilis low pH slightly reduced growth. Compared with pH 7, pH 5 resulted in a significant decrease in antibiotic activity with a delta of up to 3 log10 bacterial counts after 24 h. Impact of acidic pH was lowest for P. mirabilis; however, this strain metabolically increased the pH during experiments. Stability was not impacted by low pH. Conclusions Acidic pH had a significant negative impact on the activity of ceftolozane/tazobactam and meropenem in urine. Considering concentrations achieved in urine, our results confirm existing breakpoints and do not advocate increasing ceftolozane/tazobactam breakpoints for urinary tract infections.

Effect of the essential oils from Piper sp. and blue led lights in the enhancement of the antibiotic activity of drugs against mdr bacterial strains

2019 ◽  
Vol 199 ◽  
pp. 111604 ◽  
Author(s):  
Ana C.A. Silva ◽  
Jefferson S. Diodato ◽  
José W. Castro ◽  
Edinardo F.F. Matias ◽  
Luiz E. Silva ◽  
...  
Keyword(s):  
Essential Oils ◽  
Antibiotic Activity ◽  
Bacterial Strains ◽  
Blue Led ◽  
Led Lights

A NEW SQUASH BUG

1898 ◽  
Vol 30 (9) ◽  
pp. 239-240
Author(s):  
F. H. Chittenden
Keyword(s):  
District Of Columbia ◽  
Department Of Agriculture ◽  
Anasa Tristis ◽  
Squash Bug ◽  
Field Investigations ◽  
The Common ◽  
College Station ◽  
Official Work

In the course of an investigation of insects affecting cucurbits, begun in a preliminary way in the season of 1897, as a part of the official work of the Division of Entomology of the Department of Agriculture, it was found that we have in addition to the common squash bug, Anasa tristis, DeG., a second species sufficiently resembling it as to have readily escaped the notice of the average observer, but at the same time quite distinct in all its stages. This species is Anasa armigera, Say, and it was first observed on cucurbits by the writer July 12, near colonial Beach, Va., where it occured on cucumbers. Afterward it was taken by the writer and Mr. F. C. Pratt, of the Division of Entomology, who has assisted in field investigations and collections on different cucurbits, at Ballston, Va., Poolesville and Seat pleasant, Md., and on the Conduit Road and at Tenleytown, D. C. At the last mentioned place it occured in great abudance on a late crop of cucumbers and watermelons. As late as the 29th of September, all stages of the insect were found, including the egg. The present year the species was found to be nearly as abundant in some locaties as the common squash bug. Such was the case at Marshall Hall, Md., and in one locality in the District of columbia. It was also observed on squash at College Station and Kensington, Md., and on cucumber at Cabin John, Md.

Sign in / Sign up

Export Citation Format

Share Document