A method for testing the comprehensive friction characteristics of tube-dwelling organisms in a tube

Abstract

The present invention discloses a method for testing the comprehensive friction characteristics of tube-dwelling organisms in a tube, and belongs to the field of friction performance testing. The testing method comprises: removing the tube-dwelling animal from the tube, then cutting a piece of the tube wall after the tube is removed as a friction test substrate, anesthetizing the organism after the tube is removed by an isotonic magnesium chloride solution anesthesia method and cutting its bristles, then stimulating the organism to secrete mucus by a surface mucus scraping method, and collecting the secreted mucus, and finally sliding the cut bristles on the tube wall covered with mucus to measure the friction during the bristle sliding process. The bristle structure extracted by this method is complete and will not be deformed. At the same time, the scraped mucus is not mixed with seawater, which ensures the purity of the mucus, and the error between the friction force measured during the bristle sliding process and the theoretical value is very small, which has an important guiding role in the study of the movement mechanism of the tube-dwelling organism during the movement out of the tube, and also provides a new idea for the design of underwater adsorption equipment.

Description

Technical Field

[0001] The invention relates to the field of friction performance testing, and in particular to a method for testing the comprehensive friction characteristics of tube-dwelling organisms in a tube. Background Art

[0002] Aquatic tube-dwelling animals are filter-feeding organisms that rely on the corolla-shaped tentacles on their heads to capture floating particles in the surrounding environment to complete their feeding. A complete aquatic tube-dwelling animal consists of two parts: the organism and the mineral tube. The hard mineral tube provides protection for the softer organism. When the photoreceptors on the tentacles detect danger from the external environment, the aquatic tube-dwelling animal will quickly retreat into the tube. This process is completed in an instant. In order to avoid direct friction between the animal body and the tube wall, the aquatic tube-dwelling animal's body surface will secrete mucus to provide lubrication for the stressed entry into the tube. The mucus covers the entire body of the organism as the aquatic tube-dwelling animal moves in the tube. When the external danger is lifted, the aquatic tube-dwelling animal will crawl out of the tube and open the corolla-shaped tentacles to filter food. In this completely underwater liquid environment, the process of exiting the tube is carried out on the tube wall lubricated by mucus. Even if the external environment of exiting the tube is relatively harsh, the aquatic tube-dwelling animal can still exit the tube continuously and stably without slipping.

[0003] At present, experiments have found that the cirropod setae on both sides of the body of aquatic tube-dwelling animals play a key role in whether they can exit the tube smoothly, and the relative movement of the setae on the tube wall is a tribological behavior. However, there is no experimental test method that can represent the tribological characteristics of aquatic tube-dwelling animals during the exit process. In addition, in actual operation, there are still technical difficulties in the extraction of setae and mucus. If we forcibly pull out the setae of living aquatic tube-dwelling animals, it will cause irreversible damage to the organism and even lead to the death of the organism. Moreover, due to the small size and soft texture of the setae, the resistance of the organism during the forced removal process will cause the setae to plastically deform, which is easy to cause errors in the tribological property test experiment. Secondly, in the process of mucus extraction, because the mucus and seawater are mixed together, the purity of the mucus secreted by the organism is affected, which will cause huge errors in the viscosity test results of the mucus. Therefore, if the tribological properties of aquatic tube-dwelling animals in the process of exiting the tube can be quantitatively expressed without harming the organisms, it is expected to provide a realistic basis for the movement mechanism of aquatic tube-dwelling animals in the tube and provide a theoretical basis for the design of underwater adsorption equipment. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention removes the tube-dwelling organism from the tube and cuts off a piece of the tube wall as an experimental substrate, then stimulates the organism after the tube is removed to secrete mucus, then anesthetizes the organism to cut off its bristles, and finally uses the bristles to slide on the tube wall covered with mucus to measure the friction force, so as to solve the problem that there is no method in the prior art to test the friction force of aquatic tube-dwelling animals during the process of leaving the tube, and at the same time, it can prevent the deformation of the bristles and avoid huge errors in the test results.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows:

[0006] A method for testing the comprehensive friction characteristics of tube-dwelling organisms in a tube, the testing method comprises the following steps:

[0007] Step 1: Cut the mineral tube of the tube-dwelling organism along the tube wall, remove the organism from the tube and place it in artificial seawater, and then cut a piece of the tube wall from the mineral tube as an experimental substrate for the tribology experiment;

[0008] Step 2: Stimulate the organisms in step 1 to secrete mucus by surface mucus scraping, and collect the resulting mucus;

[0009] Step 3: anesthetize the organism after collecting mucus in step 2 by using isotonic magnesium chloride solution anesthesia, and then cut the bristles of the organism;

[0010] Step 4: Spread the mucus collected in step 2 on the tube wall cut in step 1, then let the bristles cut in step 3 slide on the tube wall, and finally test the friction generated by the bristles sliding on the tube wall.

[0011] Preferably, step 2 specifically comprises: taking out the organism from the seawater in step 1, wiping off the water on the surface of the organism, sliding back and forth on the abdomen of the organism to stimulate the organism to secrete mucus, and then scraping and collecting the mucus secreted by the organism. In this way, scraping the mucus after wiping it dry avoids the secreted mucus from being mixed with seawater, and can obtain the original mucus of the tube-dwelling organism to the maximum extent, ensuring the purity of the mucus.

[0012] Preferably, step 3 specifically comprises: preparing a magnesium chloride solution with an osmotic pressure equal to that of seawater, and then placing the organism after extracting mucus in step 2 in the magnesium chloride solution for anesthesia, and then cutting the bristles at the proximal end of the organism after observing that the papillae of the organism stop swinging. Anesthetizing the organism can not only reduce the pain of the organism in the experiment, but also cut the bristles more completely. In addition, the bristles can recover quickly after cutting, causing zero damage to the organism, and the cut bristles are complete in shape and will not undergo plastic deformation, which can be used for subsequent research on the external overall structure and internal structure of the bristles.

[0013] Preferably, the organism after the bristles are cut in step 3 is placed in a hollow glass tube with a diameter equivalent to the organism's body diameter, and then placed in artificial seawater for cultivation together to form a new tube to protect the organism.

[0014] Further preferably, the length of the hollow glass tube is 1.2-1.5 times the body length of the tube-dwelling organism.

[0015] Preferably, step 4 specifically includes: sticking the cantilever probe of the atomic force microscope onto the biological bristles cut in step 3 with glue, then spreading the tube wall cut in step 1 with the mucus collected in step 2 to create a liquid environment for the tube-dwelling organisms in the process of leaving the tube, and then letting the cantilever probe with the bristles slide on the tube wall to measure the friction force.

[0016] Further preferably, the adhesive is epoxy resin adhesive.

[0017] Preferably, the specific gravity of the artificial seawater is 1.025 and the water temperature is 25°C.

[0018] Preferably, the test environment temperature is 20° C. to 25° C. and the relative humidity is greater than 70% to avoid affecting the activity of the tube-dwelling animals.

[0019] The beneficial effects of the present invention are as follows:

[0020] The invention first removes the tube-dwelling animal from the tube and cuts off its original tube wall as a tribology experiment substrate, then anesthetizes the aquatic tube-dwelling animal through an isotonic magnesium chloride solution anesthesia method, cuts off the papillae setae on both sides of the organism, wipes the surface of the organism with a dry towel and briefly places it in the air and applies certain external stimulation to cause the surface to secrete mucus, then scrapes off the mucus with a blade to ensure that the extracted mucus is not mixed into seawater, and finally uses an atomic force microscope to measure the friction force of the cut setae in the process of sliding on the original tube wall of the organism.

[0021] The osmotic pressure magnesium chloride anesthesia method adopted by the present invention can reduce the pain of the organism during the experiment, and has zero harm to the organism. The organism can recover quickly after the bristles are cut, and the cut bristles are in complete shape and will not undergo plastic deformation, so that subsequent research on the external overall structure and internal structure of the bristles can be carried out; and the use of the blade surface to scrape the mucus can obtain the original mucus of the tube-dwelling organism to the maximum extent, ensuring the purity of the mucus. There is a very small error (within 4%) between the tribological property test and the theoretical value of the finally cut aquatic tube-dwelling animal bristles and the extracted mucus, and the tribological property of the aquatic tube-dwelling animal in the process of exiting the tube can be quantitatively expressed without harming the organism, which has an important guiding role in the study of the movement mechanism of the tube-dwelling organism in the process of exiting the tube, and also provides a new idea for the design of underwater adsorption equipment, and the test method of the present invention is simple to operate, the material is easy to obtain, and the requirements for the experimental environment are not high. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 is a flow chart of testing the comprehensive friction force of the tube-dwelling organisms in the tube in Example 1;

[0024] Figure 2 This is a diagram of the experimental operation of testing the comprehensive friction force of tube-dwelling organisms in the tube in Example 1. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely below. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. The experimental methods in the following examples are conventional unless otherwise specified.

[0026] Example 1: A method for testing the comprehensive friction characteristics of tube-dwelling organisms in a tube

[0027] The feather tube worm is a typical tube-dwelling organism that lives in a mineral tube formed by its own mucus solidification. It is a filter-feeding worm with feather-like tentacles on its crown. Under normal circumstances, the tube worm will extend its tentacles outside the tube to filter food and breathe, and when it encounters danger, it will quickly retreat into the tube to avoid danger. After the danger is eliminated, the tube worm will move out of the tube on the mucus-covered tube wall, open its feather-like tentacles and filter food again.

[0028] according to Figure 1 and Figure 2 The process and experimental operation of the test method are as follows:

[0029] 1. Tube removal: The laboratory temperature should be 20℃ to 25℃, and the relative humidity should be greater than 70%, otherwise it will affect the activity of the insect body. Select healthy and active flying feather tube worms, cut the mineral tube of the flying feather tube worm upward along the central axis of the tube to form an opening. During the operation, press with your fingers to determine the position of the flying feather tube worm to avoid cutting the organism. Then use tweezers to gently clamp the organism out of the mineral tube and clean the surface of the organism with artificial seawater (specific gravity 1.025, water temperature 25℃), then place the cleaned organism in a culture dish filled with artificial seawater (specific gravity 1.025, water temperature 25℃), finally keep the mineral tube, and use scissors to cut a 2mm×2mm tube wall from the mineral tube as the experimental substrate for the tribology experiment.

[0030] 2. Extract mucus: Take the organism from step 1 out of the culture dish filled with artificial seawater, wipe off the surface moisture with a dry towel and place it on a dry culture dish (the dry culture dish is tilted to facilitate the concentration of biological mucus) and let it stand for about 1 minute. Then use a glass rod to gently slide back and forth on the abdomen of the organism to stimulate the organism to secrete more mucus. Use a blade to slowly scrape the mucus on the surface of the organism in the culture dish. Finally, use a pipette to transfer the mucus to a 30ml test tube, and then put the organism back into the culture dish filled with artificial seawater and let it stand for 5 minutes. After the organism recovers its activity, repeat the steps of "stimulating the organism-scraping mucus" until the 30ml test tube is filled with mucus.

[0031] 3. Cutting bristles: Prepare a magnesium chloride solution with an osmotic pressure equal to that of seawater (specific gravity 1.025, water temperature 25°C) and place it in a culture dish. Then move the organism from which the mucus has been scraped in step 2 into the culture dish containing the magnesium chloride solution and let it stand for about 5 minutes. Then use a microscope to observe whether the organism's warty feet continue to swing. If they stop swinging, it means that the organism has been anesthetized. Otherwise, continue to place it in the magnesium chloride solution until the organism's warty feet stop swinging. Finally, use surgical scissors to cut the bristles at the proximal end of the organism's crown. After drying the cut bristles, place them in a centrifuge tube for storage.

[0032] 4. Artificial tube replacement: Measure the body diameter of the flying feather tube worm in step 3, select a hollow glass tube with a diameter equivalent to the body diameter and a tube length 1.2-1.5 times the body length of the organism, use tweezers to put the tail of the feather tube worm into the glass tube, and then immerse the glass tube vertically in artificial seawater (specific gravity 1.025, temperature 25°C), the mouth of the glass tube is slightly higher than the water surface to ensure that the tail of the tube worm in the glass tube is in contact with the water, and the rest of the body is not in contact with the water. At this time, the tube worm will move underwater autonomously until it completely enters the new tube and is placed in the ecological tank for re-cultivation. After culturing for more than 3 days, you can see that the organism will have new tubes growing. This is because step 1 has damaged the original tube of the organism, so in order to not damage the soft organism when the organism is re-placed in the sea tank, it is necessary to artificially transplant a new tube to protect the organism.

[0033] 5. Test the friction force of the bristle sliding on the tube wall

[0034] (1) Take two clean glass slides 1 and 2 respectively, apply epoxy resin glue on the glass slide 1, and place the setae of the quillworm cut in step 3 on the glass slide 2. Before the epoxy resin glue on the glass slide 1 hardens, operate an atomic force microscope (Bruker, dimension fastscan bio) to make the cantilever probe stained with epoxy resin glue, then quickly press the biological setae on the glass slide 2 so that the biological setae adhere to the cantilever probe, and then let it stand for one hour until the epoxy resin glue is completely dry;

[0035] (2) Take the tube wall cut in step 1 and the mucus extracted in step 2, spread the mucus on the tube wall to create a liquid environment during the tube process, and then operate the atomic force microscope (Bruker, dimension fastscan bio) so that the cantilever beam probe on the atomic force microscope (Bruker, dimension fastscan bio) drives the bristles to slide on the tube wall, thereby measuring the friction force of the bristles sliding on the tube wall. The theoretical calculation formula of friction force is as follows:

[0036]

[0037] Among them, μ is the viscosity of the mucus, H is the thickness of the liquid film formed by the mucus on the tube wall, S is the area of ​​the side where the bristle contacts the tube wall, and V is the sliding speed of the bristle in the horizontal direction.

[0038] The measured μ is 2.5 cPs, H is 0.132 mm, and S is 2×10 -3 mm 2, V is 0.1 mm / s, and the theoretical value of the friction force substituted into the theoretical calculation formula is 0.438 μN. The friction force of the bristle sliding on the tube wall measured by atomic force microscopy (Bruker, dimension fastscan bio) is 0.42 μN, with an error range of less than 4%, which is within the acceptable range of experimental error.

[0039] 6. Test the viscosity of the mucus of the flying quill insect

[0040] A rotational rheometer (MCR52, Anton Paar) was used to test the viscosity of the feather tube worm mucus extracted in step 2, and the measured mucus viscosity was 2.8±0.15 cPs. In the same environment, the viscosity of the feather tube worm mucus directly scraped and measured was 2.5±0.2 cPs. Therefore, the viscosity of the mucus extracted in step 2 is greater, which indicates that the lower the water content in the mucus, the higher the purity of the extracted mucus. After the organism is taken out of the primary tube, the excess seawater on the surface is wiped off with a dry towel and the organism is briefly placed in the gas phase. At this time, the mucus secreted by the organism in the gas phase does not contain seawater and can be regarded as pure mucus.

[0041] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for testing the comprehensive friction characteristics of tube-dwelling organisms in a tube, characterized in that: The test method steps are as follows: Step 1: Cut the mineral tube of the tube-dwelling organism along the tube wall, remove the organism from the tube and place it in artificial seawater, and then cut a piece of the tube wall from the mineral tube as an experimental substrate for the tribology experiment; Step 2: Stimulate the organisms in step 1 to secrete mucus by surface mucus scraping, and collect the resulting mucus; Step 3: anesthetize the organism after collecting mucus in step 2 by using isotonic magnesium chloride solution anesthesia, and then cut the bristles of the organism; Step 4: Spread the mucus collected in step 2 on the tube wall cut in step 1, then let the bristles cut in step 3 slide on the tube wall, and finally test the friction generated by the bristles sliding on the tube wall.

2. The method for testing the comprehensive friction characteristics of tube-dwelling organisms in a tube according to claim 1, characterized in that: The step 2 specifically includes: taking out the organism from the artificial seawater in step 1, wiping off the moisture on the surface of the organism and sliding back and forth on the abdomen of the organism to stimulate the organism to secrete mucus, and then scraping and collecting the mucus secreted by the organism.

3. The method for testing the comprehensive friction characteristics of tube-dwelling organisms in a tube according to claim 1, characterized in that: The step 3 specifically comprises: preparing a magnesium chloride solution with an osmotic pressure equal to that of artificial seawater, and then placing the organism after the mucus is extracted in step 2 in the magnesium chloride solution for anesthesia, and cutting the bristles at the end of the organism after the papillae of the organism stop swinging.

4. The method for testing the comprehensive friction characteristics of tube-dwelling organisms in a tube according to claim 1 or 3, characterized in that: The organism after the bristles are cut in step 3 is placed in a hollow glass tube with a body diameter equivalent to that of the organism, and then placed in artificial seawater for cultivation together to form a new tube to protect the organism.

5. The method for testing the comprehensive friction characteristics of tube-dwelling organisms in a tube according to claim 4, characterized in that: The length of the hollow glass tube is 1.2-1.5 times the body length of the tube-dwelling organism.

6. The method for testing the comprehensive friction characteristics of tube-dwelling organisms in a tube according to claim 1, characterized in that: The step 4 specifically includes: using glue to stick the cantilever probe of the atomic force microscope onto the bristles of the organism cut in step 3, and then spreading the mucus collected in step 2 on the tube wall cut in step 1 to create a liquid environment for the tube-dwelling organisms in the process of leaving the tube, and then letting the cantilever probe with the bristles slide on the tube wall to measure the friction force.

7. The method for testing the comprehensive friction characteristics of tube-dwelling organisms in a tube according to claim 6, characterized in that: The adhesive is epoxy resin adhesive.

8. The method for testing the comprehensive friction characteristics of tube-dwelling organisms in a tube according to claim 1, characterized in that: The specific gravity of the artificial seawater is 1.025 and the water temperature is 25°C.

9. The method for testing the comprehensive friction characteristics of tube-dwelling organisms in a tube according to claim 1, characterized in that: The test environment temperature is 20℃ to 25℃, and the relative humidity is greater than 70%.

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