Microsatellite Genotyping for Heartworm Isolate Differentiation

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Solution Overview

Problem

Current methods for testing heartworm drugs are inefficient due to the need to test against multiple drug-susceptible and resistant isolates, increasing the number of hosts and costs required, especially in the context of emerging macrocyclic lactone resistance in Dirofilaria immitis.

Innovation Solution

The use of polymorphic microsatellite markers, specifically Dims3, Dims4, Dims7, Dims16, and Dims19, to differentiate between heartworm isolates such as JYD-34, GA III, and SC-20, allowing for efficient identification and testing of new products using PCR amplification and primer-based differentiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple heartworm isolates are tested using traditional methods, then drug resistance can be detected, but the number of hosts and costs increase significantly

Engineering Contradiction:
Improvedrug resistance detectionVSAvoidnumber of hosts
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent combines multiple heartworm isolates (drug-susceptible and drug-resistant) into a single host for co-infection studies. This merging approach allows simultaneous detection of drug resistance phenotypes without requiring separate hosts for each isolate, directly reducing the total number of hosts needed while maintaining reliable resistance detection capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The microsatellite markers developed in the patent serve multiple functions: they can differentiate between various heartworm isolates, determine genotypes, and detect drug resistance phenotypes. This multi-functionality allows a single testing system to replace multiple separate testing protocols that would otherwise require multiple hosts

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If multiple heartworm isolates are tested using traditional methods, then drug resistance can be detected, but costs increase significantly

Engineering Contradiction:
Improvedrug resistance detectionVSAvoidtesting cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By merging multiple isolate testing into a single co-infection model, the patent reduces the overall cost structure of drug resistance detection. The combined approach eliminates redundant testing procedures and reduces material consumption per isolate, directly lowering testing costs while maintaining detection reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses microsatellite marker profiles as genetic copies or fingerprints to identify and differentiate heartworm isolates. This molecular copying approach replaces the need for maintaining and testing multiple physical isolate cultures separately, reducing the operational costs associated with isolate maintenance and testing

Inventive Principle:
Principle #26Copying

3Quantity of substance

If microsatellite markers are used to differentiate heartworm isolates, then the number of animals needed is reduced, but the complexity of genotyping increases

Engineering Contradiction:
Improvenumber of animalsVSAvoidgenotyping complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent segments the complex genotyping process into manageable components by selecting specific microsatellite marker loci that can be analyzed independently through PCR amplification. This segmentation allows the use of standard molecular biology techniques rather than requiring complex whole-genome analysis, making the genotyping process more tractable despite the need to differentiate multiple isolates

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of analysis from phenotypic observation to genotypic characterization using microsatellite markers. By shifting to genetic parameter analysis, the system achieves more precise isolate differentiation with fewer animals, as genetic markers provide definitive identification without requiring large sample sizes for statistical confidence

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables the differentiation of heartworm isolates in a single host, reducing the number of animals needed for research and testing, thereby decreasing costs and improving the efficiency of drug testing models.

Implementation Method 1

PCR amplifying the isolated DNAs using one or more corresponding primers of disclosed herein

Methodology Applied
Scientific EffectPCR amplification: Enzyme

Data Source

PatentUS20230313318A1Microsatellite genotyping and method of use thereof
Publication Date: 2023.10.05 TRS LABS INC

AI summary

Microsatellite markers, and method of use thereof, for differentiating isolates of D. immitis heartworms and/or other parasites. A method of testing new products for drug-susceptible and/or resistant isolates of heartworms using the microsatellite markers disclosed herein.