Isolation of Nematodes from a Soil Sample

This experiment about isolation of nematodes was mainly geared to determine the presence of  nematodes in the soil. The experiment was done in the laboratory by the use of the common tools that were found in the laboratory. The experiment took about one and a half hours before the final separation of the worms. The soil samples were obtained from the backyard of Dr.Bradly’s house. This paper begins with an introductory part that gives highlights on the nematodes. The methods and procedures used in the experiment are easy to follow and understand. The paper has a conclusion that summarizes the paper and a recommendation part before the reference list.

Introduction

Nematodes are the living organisms commonly known as round worms. Amongst all the animals in the universe, nematodes are the most numerous and have been known to  be common in most places. Most of the people who have studied the worms report that in a handful of soil one can collect thousands of microscopic worms. Nematodes belong to a phylum called phylum nematoda. They are the most diverse of all the animals. Most of the nematodes are parasitic, and are parasites to plants and animals. Nematodes can be found in a many ecosystems. They are found in the fresh water, marine water, and soils. They can also be found in the polar regions and the temperate regions in the world (Weischer and  Brown, 2000). About 50% of nematodes live on the ocean. 15 % of nematodes live in animal or human and 35% in soil and fresh water. Only 10 % of fresh and soil water nematodes exist as parasites on plant and cause diseases.

Nematodes are multicellular organisms that have a simple structure. They have a tubular body with a reproductive system and an alimentary canal. They have two opening, one at the anterior side and the other at the posterior side as the anal opening before the tail. They also have a nervous system, but do not have a circulatory system. Most nematodes measure 1 to 5 mm long. In order to study the nematodes it is important that one isolates the microorganisms from the source. In this case, the practical is about isolating the nematodes from soil samples obtained from Dr. Bradly’s garden. The method that is used to isolate the nematodes is by culture and sieving techniques. There are many ways that can be used to isolate nematodes, but the easiest method is by the use of a substrate e.g. bacterial cultures.

To obtain a live culture of bacteria, a little smear from the colonies previously cultured was obtained and sub cultured in agar. This was cultured for about 12-24 hours from which a pure bacterial culture was  obtained. The sample of soil from the back yard was moistened a little with water.

A few colonies were obtained from the culture and inoculated in a fresh agar. The colonies were placed at the center of the agar. Then he moistened soil was arranged in the same plate besides the bacterial colonies. The plate was then covered and left for about 1 hour.

After 1 hour, the plate was observed by the use of a magnifying glass. It was noted that the were nematodes that were coming out of the soil towards the bacterial colonies. These worms were then directly picked, and put in separate petri dish. The nematode picked were both male and female nematodes.

A rubber tube was fit on the stem of the funnel. The tube is then closed by the use of a clamp. Then a solution that supports the viability of the nematodes is filled into the tube, which fit at the neck of the funnel. On the funnel,  a piece of sieve input and on to it is added the soil sample. The sieve is folded to enclose the soil on the sieve and again on top of the soil sample is added the solution with nutrients for the nematodes. After a while, observations were made on the set up (Félix and Barrière, 2006).

Results

After about 1 hour, it was noticed that come few nematodes were crawling out of the sieve in the funnel. The nematodes had sedimented at the bottom and stuck on the side of the funnel. The isolation process was extended for several days to obtain more nematodes. The nematodes were then collected directly from the funnel to another petri dish for study.

Discussion

There are many types of nematodes that can be isolated from different ecosystems. These nematodes feed on different substrates including bacteria. Most of the nematodes that are found in the soil feed on the bacteria while others decomposed the organic matter in the soil. In this experiment, the target nematodes were the class of nematodes that feed on bacteria.

The use of a fresh culture was to ensure that one obtains a pure culture of bacteria that would be efficient in attracting the nematodes in the culture plate. The soil was also moistened so that the worms in the plate would stay viable. As  a result, reduce the motility rate of the nematodes. It was important to use the magnifying glass to observe the changes in the culture plate because there are some nematodes that are microscopic.

This method of separation is particularly advantageous. This is because, during the experiment, a person also has the chance to observe the development stages of different nematodes in the soil sample.

In the sieve experiment, the method is much easy and more general. In this method, one can easily do the isolation even by the use of locally made tools and materials. However, one has to ensure that the material that is used is sterile and clean

The method is also advantageous compared to the first method. In this method, one can get the many isolates because the method is not specific. While on the isolation by culture, the nematodes that will be recovered will be the few that depend on the bacteria for survival. These are likely to come out easily due to the source of nutrient.

Conclusions

In conclusion, the separation of nematodes is essential in everyday life. The importance of isolating nematodes cannot be assumed, or overlooked. This is because of the fact that they play a significant role in human and animal life. While nematodes are the most numerous microorganisms in the soil, nematodes are responsible for most of the pathogenic disorders in plants and animals. Saliva secreted by nematode may cause a dead of the cell or other abnormalities such as hypertrophy and hyperplasia. These responses appear as a symptom on infected plant. Poor growth, yellowing, and gall are several of symptoms that may be observed on nematode infected plant. However, not all nematodes are disease causative agents.

Number of plant parasitic nematode is not much. They only comprise 10% of 35% of soil and fresh water nematode. Tough the number is not much; plant nematode may cause a huge problem in crop plant. The Juvenile 2 is the infective stage in many genera of plant parasitic nematode. The feeding activity of nematode affects the physiological function of plant. Interrelationship between nematode and other pathogen may increase the disease severity and incidence.

Recommendation                                                                        

The isolation process is a recommendable procedure that is significant in the studying of the nematodes today. Through the isolation process, one can get to know the types of nematodes that exist. This study goes a long way in establishing the procedures and treatment of different pathogenic disorders for both human and plants. Hence, it is beneficial that nematodes be isolated and studied for future development (Kakouli-Duarte and Wilson, 2009).