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[Music]

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hello my name is pratisha sai machinini

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i am a master's student at the

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university of houston

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clear lake in houston texas i am

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currently working on my master's in

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biotechnology

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and i am currently working on my thesis

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project

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pathways for microbial perchlorate

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reduction in a mars analog environment

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to start off with some background we

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will be talking about the mars

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and the analog environment first so

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during the phoenix lander mission

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perchlorate was detected and observed at

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the

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vasatas borealis landing site

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perchlorate was also evident in the rock

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nest

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sand patches of the gale gale crater

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gathered by the curiosity rover in

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2012 also after the viking land

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emissions

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evaluation and detection of perchlorate

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it can mean that it is globally

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distributed

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across mars martian perchlorate can be

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an essential

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energy and oxygen research for future

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exploration

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there are places on earth that are

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analog environments

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these include the atacama desert in

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chile

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morocco and the pilot valley basin in

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utah

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usa these environments have shown

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abundance of perchlorate examining

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different sites for

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biological and geological study can

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provide an interpretation

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of the biosignatures for comprehending

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the evolution

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of the martian environment and possibly

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so for some basic on perchlorate

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so perchlorate or clo4 minus is a highly

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oxidizing anion with an oxidation state

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of plus 7 and a redox potential of 1.287

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volts anthropogenic perchlorate

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in the environment results from various

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industries such as

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rocket propellants pyrotechnics

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fireworks and the chemical industry

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perchlorate has been mainly studied as a

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drinking water contaminant

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because pleurcherate perchlorate can be

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a health threat to the thyroid

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by the inhibition of the uptake of

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iodide

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i also have cited the papers along with

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the pictures just for a reference

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as well and they will also be shown at

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the end of the presentation

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for further reading

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[Music]

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so this picture shows the different

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pathways

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including the enzymes and how it breaks

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down

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so there are known different reduction

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pathways which include

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canonical symbiotic and cryptic

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the common perchlorate reduction pathway

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is canonical

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perchlorate reduction which includes

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specific

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enzymes pcra

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known as perchlorate reductase and cld

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known as chloride dismutase

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the cld enzyme is also present across

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chloride reducing bacteria and nitrate

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oxidizing bacteria which also uses

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nyxar which is another type of specific

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enzyme

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only specific to or plausibly only

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specific to

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nitrite oxidizing bacteria

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the symbiotic pathway has

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so far only been observed in the

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laboratory and not in the environment

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cryptic perchlorate reduction is noted

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as

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an incomplete reduction because of the

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lack of the cld

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enzyme or chlorite dismutase

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and it also has only been observed in

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the laboratory

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just like symbiotic

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the significance of cryptic perchlorate

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reduction

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in the environment is anticipated for

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further further

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studies as it could be an evolutionary

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step

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in the timeline of perchlord and as

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shown in this figure

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we can see how it is broken down through

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pcra

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and cld so the end products are chloride

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and this is the paper that the figures

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[Music]

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reading

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so a previous study by lynch etl 2019

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a previous study has shown evidence of

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naturally occurring perchlorate or

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nlp found in the sediments of the pilot

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valley basin

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utah according to the study site pv4

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[Music]

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has shown a greater concentration of

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perchlorate and microbial

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microbially induced sedimentary

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structures also called

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[Music]

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prms or perchlorate reducing microbes

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have been found to be very

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phylogenetically diverse

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it has been seen that perchlorate

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reducing microbes

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have been found to coexist with

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naturally occurring perchlorate or

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nop from data of 16

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srrna gene sequences both from sites pv3

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and sld sld-124

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shows what phylums or which phylums

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are dominant pv3 showed proteobacteria

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and bacterioids

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are greater and sld124 shows that

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bacterioids and from

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fermicutes are dominant known taxonomic

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groups for prms are azospira

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halobacterium and suitamonas

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to date over 40 isolates of perchlorate

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reducing microorganisms

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perchlorate reducers are facultative

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anaerobes and can be inhibited by oxygen

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and nitrate prms or

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perchlorating perchlorate reducing

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microorganisms

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have been commonly associated with the

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subclasses

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of alpha beta gamma and epsilon

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of the proteobacteria phylum

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[Music]

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the main goal for this project is to

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identify

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which microorganisms metabolize

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naturally occurring

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perchlorate in pilot valley why and how

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they are doing it

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another important question is why is it

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[Music]

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environment

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so a basic overview the pathways that

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prms

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use are not entirely known previous work

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has shown that the canonical

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perchlorate reduction pathway is likely

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not

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the primary metabolic pathway

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nitrate reducing microorganisms are also

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known to reduce perchlorate through

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nitrate reductase

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a plausible pathway is through nitrate

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reducing microbes due to the evidence of

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the nrg

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type reductase gene and the presence

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of nitrate reducing microbial species

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[Music]

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enrichments have been already initiated

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by dr kendall lynch from 2019

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the samples are housed in a minimal

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enrichment media to match the

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geochemistry of the pilot valley basin

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there are perchlorate samples chloride

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samples nitrate sample

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and blank samples that contain no

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oxyanions

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we also have a kill control the samples

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are interacted

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with an anaerobic chamber to maintain

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anoxic

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since samples were since working with

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the samples a lot of

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protocol development has come away

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we've been trying many ways to obtain

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better dna yield and concentration

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so the the way we came up with it

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is we would obtain fresh sample from

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culture bought

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from the culture bottle the dna samples

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are used for dna extraction

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with in triplicates plus a blink the

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samples are then

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cleaned up and concentrated to obtain

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cleaner dna

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and removing extra hemic substances

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these samples are quantified

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with a cubit fluorometer

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qpcr will be used to is used to detect

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nargi and cld the standards are derived

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from a known perchlorate reducer which

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is

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the chloromonas agitator the main goal

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is to identify the key enzymes in the

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pathways and identify the microorganisms

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and we hope that nrg will show an

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increase in cld will show an increase

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as well some further research

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through the continued studied of

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per-court-reducing microbes main

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perchlorate reduction pathways

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can be identified for metabolic energy

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genomic analysis and characterizations

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of

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prms through rna sequencing can also be

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done

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a perchlorate based ecosystem model

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could be produced to study the

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implications of past

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present and future habitable zones on

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mars

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finally i would like to thank the

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university of houston clear lake

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the lunar planetary institute also known

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as lpi

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usra and nasa for the opportunity and

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funding to work on this project

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i would like to thank my pi dr kendall

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lynch and dr laurie santiago asquez

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for their guidance knowledge and support

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on this project

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i would also like to thank jessica lopez

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for her help in the lab

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i would also like to thank ab grad khan

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for the opportunity

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here are the references that are

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mentioned in this