Growth and Morphological Growth and Morphological Variation in Microorganisms Variation in Microorganisms

Exposed to Lead Exposed to Lead

JOE TONEY*, DANIELLE DAY, JENNIFER JOE TONEY*, DANIELLE DAY, JENNIFER SEABAUGH, ANDREW CORCORAN, SEABAUGH, ANDREW CORCORAN, JENNIFER ARNOLD, and JAMES E. JENNIFER ARNOLD, and JAMES E.

CHAMPINECHAMPINESoutheastSoutheast Missouri State University Missouri State University

Lead Mining in MissouriLead Mining in Missouri

• Lead-belt region (Mineral Area College)

• Chat: mine tailings covering acres of land

• Hypothesis: Natural enrichment for lead-resistant microorganisms

Lead Content, ppm, of Soil and ChatLead Content, ppm, of Soil and Chat

Fraction Sample 12 Soil

Sample 14 Chat

Sample 15 Soil

Total

Bioavailable

2,725 16,733 1,289

Total 4,023 16,733 2,294

Isolates Pb4, Pb5 CPA 1,2,6

CPC 2,3,4,5

Pb1, Pb3

ApproachApproach

• Bacteria were eluted from chat and applied to the surface of agar plates.

• Defined chemical media containing lead called “Roane Media”

• This media is formulated to minimize precipitation of lead.

• Equation– [Pb]sol = 0.045[Pb]tot-0.12

mM

My IsolatesMy IsolatesCPC2 CPC3

CPC5CPC4

TSA RM

RM 1mM

RM 2.5mM

CPC5=CPA6=Pb5CPC5=CPA6=Pb5Rhodococcus fascians (luteus)Rhodococcus fascians (luteus)

CPC3=CPA1CPC3=CPA1

• Gram positive species not in the MIDI database

• Microbacterium (Corynebacterium) laevinformans

Lead

No Lead

Serratia marcescensSerratia marcescens

No Lead Lead

EnterobacterEnterobacter

Pb3O4PbOPbO2

No Lead

Lead

Gradient PlatesGradient Plates

Safranin Crystal Violet

Gradient Discontinuous Gradient

CPC5

0 mM Pb

5 mM Pb

NoGrowth

Reasons for Color VariationReasons for Color Variation

• Secondary Metabolism– Pigments produced in

response to stress– Serratia marcescens– Test by pigment

extraction procedures

• Precipitation of Pb– Found in Fungal

Isolate Pb3– Coloration resembles

Lead Oxides and/or Phosphate

– Test by Electron Microscopy and Electron Diffraction Studies

AcknowledgementsAcknowledgements

• Coauthors– Jennifer Seabaugh– Danielle Day– James Collins

• Jennifer Arnold, Andrew Corcoran

• Maija Bluma• Funding from SEMO

Undergraduate Research Program