Latex

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Tapping of latex from a tree, for use in rubber production Latex-production.jpg
Tapping of latex from a tree, for use in rubber production

Latex is an emulsion (stable dispersion) of polymer microparticles in water. [1] Latices are found in nature, but synthetic latices are common as well.

Contents

In nature, latex is found as a milky fluid, which is present in 10% of all flowering plants (angiosperms). [2] It is a complex emulsion that coagulates on exposure to air, consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins, and gums. It is usually exuded after tissue injury. In most plants, latex is white, but some have yellow, orange, or scarlet latex. Since the 17th century, latex has been used as a term for the fluid substance in plants, deriving from the Latin word for "liquid". [3] [4] [5] It serves mainly as defense against herbivorous insects. [2] Latex is not to be confused with plant sap; it is a distinct substance, separately produced, and with different functions.

The word latex is also used to refer to natural latex rubber, particularly non-vulcanized rubber. Such is the case in products like latex gloves, latex condoms, latex clothing, and balloons.

IUPAC definition.

Latex: Colloidal dispersion of polymer particles in a liquid. [6] [lower-alpha 1]
Synthetic latex: Latex obtained as a product of an emulsion, mini-emulsion, micro-emulsion, or dispersion polymerization. [6]

Biology

Articulated laticifers

The cells (laticifers) in which latex is found make up the laticiferous system, which can form in two very different ways. In many plants, the laticiferous system is formed from rows of cells laid down in the meristem of the stem or root. The cell walls between these cells are dissolved so that continuous tubes, called latex vessels, are formed. Since these vessels are made of many cells, they are known as articulated laticifers. This method of formation is found in the poppy family and in the rubber trees (Para rubber tree, members of the family Euphorbiaceae, members of the mulberry and fig family, such as the Panama rubber tree Castilla elastica ), and members of the family Asteraceae. For instance, Parthenium argentatum the guayule plant, is in the tribe Heliantheae; other latex-bearing Asteraceae with articulated laticifers include members of the Cichorieae, a clade whose members produce latex, some of them in commercially interesting amounts. This includes Taraxacum kok-saghyz , a species cultivated for latex production. [7]

Non-articulated laticifers

In the milkweed and spurge families, on the other hand, the laticiferous system is formed quite differently. Early in the development of the seedling, latex cells differentiate, and as the plant grows these latex cells grow into a branching system extending throughout the plant. In many euphorbs, the entire structure is made from a single cell – this type of system is known as a non-articulated laticifer, to distinguish it from the multi-cellular structures discussed above. In the mature plant, the entire laticiferous system is descended from a single cell or group of cells present in the embryo.

The laticiferous system is present in all parts of the mature plant, including roots, stems, leaves, and sometimes the fruits. It is particularly noticeable in the cortical tissues. Latex is usually exuded as a white liquid, but is some cases it can be clear, yellow or red, as in Cannabaceae. [2]

Productive species

Latex is produced by 20,000 flowering plant species from over 40 families. These include both dicots and monocots. Latex has been found in 14 percent of tropical plant species, as well as six percent of temperate plant species. [8] Several members of the fungal kingdom also produce latex upon injury, such as Lactarius deliciosus and other milk-caps. This suggests it is the product of convergent evolution and has been selected for on many separate occasions. [2]

Defense function

Rubber tapping latex Latex being collected from a tapped rubber tree.jpg
Rubber tapping latex

Latex functions to protect the plant from herbivores. The idea was first proposed in 1887 by Joseph F. James, who noted that latex of milkweed

carries with it at the same time such disagreeable properties that it becomes a better protection to the plant from enemies than all the thorns, prickles, or hairs that could be provided. In this plant, so copious and so distasteful has the sap become that it serves a most important purpose in its economy. [9]

Evidence showing this defense function include the finding that slugs will eat leaves drained of their latex but not intact ones, that many insects sever the veins carrying latex before they feed, and that the latex of Asclepias humistrata (sandhill milkweed) kills by trapping 30% of newly hatched monarch butterfly caterpillars. [2]

Other evidence is that latex contains 50–1000× higher concentrations of defense substances than other plant tissues. These toxins include ones that are also toxic to the plant and consist of a diverse range of chemicals that are either poisonous or "antinutritive."

Latex is actively moved to the area of injury; in the case of Cryptostegia grandiflora , latex more than 70 cm from the site of injury is mobilized. [2] The large hydrostatic pressure in this vine enables an extremely high flow rate of latex. In a 1935 report the botanist Catherine M. Bangham observed that "piercing the fruit stalk of Cryptostegia grandiflora produced a jet of latex over a meter long, and maintained [this jet] for several seconds." [10]

The clotting property of latex is functional in this defense since it limits wastage and its stickiness traps insects and their mouthparts. [2]

While there exist other explanations for the existence of latex including storage and movement of plant nutrients, waste, and maintenance of water balance that "[e]ssentially none of these functions remain credible and none have any empirical support". [2]

Applications

Opium poppy exuding fresh latex from a cut Opium pod cut to demonstrate fluid extraction1.jpg
Opium poppy exuding fresh latex from a cut

The latex of many species can be processed to produce many materials.

Personal and healthcare products

Natural rubber is the most important product obtained from latex; more than 12,000 plant species yield latex containing rubber, though in the vast majority of those species the rubber is not suitable for commercial use. [12] This latex is used to make many other products including mattresses, [13] gloves, swim caps, condoms, catheters and balloons.[ citation needed ]

Opium and opiates

Dried latex from the opium poppy is called opium, the source of several useful analgesic alkaloids such as codeine, thebaine, and morphine, the latter two of which can then further be used in the synthesis and manufacture of other (typically stronger) opioids for medicinal use, and of heroin for the illegal drug trade. The opium poppy is also the source of medically useful non-analgesic alkaloids, such as papaverine and noscapine.[ citation needed ]

Clothing

Latex is used in many types of clothing. Worn on the body (or applied directly by painting), it tends to be skin-tight, producing a "second skin" effect. [14]

Industrial and biological applications of synthetic latices

Synthetic latices are used in coatings (e.g., latex paint) and glues because they solidify by coalescence of the polymer particles as the water evaporates. These synthetic latices therefore can form films without releasing potentially toxic organic solvents in the environment. Other uses include cement additives and to conceal information on scratchcards. Latex, usually styrene-based, is also used in immunoassays. [15]

Allergic reactions

Some people only experience a mild allergy when exposed to latex, with symptoms such as eczema, contact dermatitis, or developing a rash. [16]

Others have a serious latex allergy, and exposure to latex products such as latex gloves can cause anaphylactic shock. Guayule latex has only 2% of the levels of protein found in Hevea latices, and it is being researched as a lower-allergen substitute. [17] Additionally, chemical processes may be employed to reduce the amount of antigenic protein in Hevea latex, yielding alternative materials such as Vytex Natural Rubber Latex which provide significantly reduced exposure to latex allergens.

About half of people with spina bifida are also allergic to natural latex rubber. People who have had multiple surgeries and who have had prolonged exposure to natural latex are also more susceptible to a latex allergy. [18]

Latex-fruit syndrome

Many people with latex allergy also experience allergic reactions to certain fruits. This association has led to research regarding latex-fruit syndrome (LFS). This is a phenomenon characterized by cross-reactivity between natural latex rubber allergens and certain fruit allergens, leading to allergic reactions in sensitized individuals. It was described for the first time by Blanco et al. in 1994. [19]

In a 2024 comprehensive review by Gromek et al., the last 30 years of research on LFS were summarized, focusing on its prevalence, common cross-reactions, and clinical manifestations. The review found that the prevalence of LFS in latex-allergic patients varies widely, ranging from 4% to 88%, depending on diagnostic methods, geographical regions, and study populations. The most commonly implicated fruits in LFS include banana, avocado, kiwifruit, and papaya. Clinical manifestations are predominantly systemic, with 73% of hypersensitivity symptoms being systemic and 27% localized. Gromek et al. also highlighted the need for standardized diagnostic criteria and severity grading systems to improve the accuracy of LFS diagnosis and treatment. [20]

Microbial degradation

Several species of the microbe genera Actinomycetes , Streptomyces , Nocardia , Micromonospora , and Actinoplanes are capable of consuming rubber latex. [21] However, the rate of biodegradation is slow, and the growth of bacteria utilizing rubber as a sole carbon source is also slow. [22]

See also

Notes

  1. ↑ The polymer in the particles may be organic or inorganic. [6]

Related Research Articles

<span class="mw-page-title-main">Natural rubber</span> Polymer harvested from certain trees

Rubber, also called India rubber, latex, Amazonian rubber, caucho, or caoutchouc, as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, Indonesia, and Cambodia are four of the leading rubber producers.

<span class="mw-page-title-main">Allergy</span> Immune system response

Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic dermatitis, allergic asthma, and anaphylaxis. Symptoms may include red eyes, an itchy rash, sneezing, coughing, a runny nose, shortness of breath, or swelling. Note that food intolerances and food poisoning are separate conditions.

An allergen is an otherwise harmless substance that triggers an allergic reaction in sensitive individuals by stimulating an immune response.

<span class="mw-page-title-main">Neoprene</span> Chemical compound

Neoprene is a family of synthetic rubbers that are produced by polymerization of chloroprene. Neoprene exhibits good chemical stability and maintains flexibility over a wide temperature range. Neoprene is sold either as solid rubber or in latex form and is used in a wide variety of commercial applications, such as laptop sleeves, orthopaedic braces, electrical insulation, medical gloves, liquid and sheet-applied elastomeric membranes or flashings, and automotive fan belts.

<span class="mw-page-title-main">Allergic rhinitis</span> Nasal inflammation due to allergens in the air

Allergic rhinitis, of which the seasonal type is called hay fever, is a type of inflammation in the nose that occurs when the immune system overreacts to allergens in the air. Signs and symptoms include a runny or stuffy nose, sneezing, red, itchy, and watery eyes, and swelling around the eyes. The fluid from the nose is usually clear. Symptom onset is often within minutes following allergen exposure, and can affect sleep and the ability to work or study. Some people may develop symptoms only during specific times of the year, often as a result of pollen exposure. Many people with allergic rhinitis also have asthma, allergic conjunctivitis, or atopic dermatitis.

<span class="mw-page-title-main">Food allergy</span> Hypersensitivity reaction to a food

A food allergy is an abnormal immune response to food. The symptoms of the allergic reaction may range from mild to severe. They may include itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressure. This typically occurs within minutes to several hours of exposure. When the symptoms are severe, it is known as anaphylaxis. A food intolerance and food poisoning are separate conditions, not due to an immune response.

<span class="mw-page-title-main">Contact dermatitis</span> Inflammation from allergen or irritant exposure

Contact dermatitis is a type of acute or chronic inflammation of the skin caused by exposure to chemical or physical agents. Symptoms of contact dermatitis can include itchy or dry skin, a red rash, bumps, blisters, or swelling. These rashes are not contagious or life-threatening, but can be very uncomfortable.

<span class="mw-page-title-main">Latex allergy</span> Medical condition

Latex allergy is a medical term encompassing a range of allergic reactions to the proteins present in natural rubber latex. It generally develops after repeated exposure to products containing natural rubber latex. When latex-containing medical devices or supplies come in contact with mucous membranes, the membranes may absorb latex proteins. In some susceptible people, the immune system produces antibodies that react immunologically with these antigenic proteins. Many items contain or are made from natural rubber, including shoe soles, pen grips, hot water bottles, elastic bands, rubber gloves, condoms, baby-bottle nipples, and balloons; consequently, there are many possible routes of exposure that may trigger a reaction. People with latex allergies may also have or develop allergic reactions to some fruits, such as bananas.

<span class="mw-page-title-main">Styrene-butadiene</span> Synthetic rubber polymer

Styrene-butadiene or styrene-butadiene rubber (SBR) describe families of synthetic rubbers derived from styrene and butadiene. These materials have good abrasion resistance and good aging stability when protected by additives. In 2012, more than 5.4 million tonnes of SBR were processed worldwide. About 50% of car tires are made from various types of SBR. The styrene/butadiene ratio influences the properties of the polymer: with high styrene content, the rubbers are harder and less rubbery. SBR is not to be confused with the thermoplastic elastomer, styrene-butadiene block copolymer, although being derived from the same monomers.

<span class="mw-page-title-main">Allergic conjunctivitis</span> Medical condition

Allergic conjunctivitis (AC) is inflammation of the conjunctiva due to allergy. Although allergens differ among patients, the most common cause is hay fever. Symptoms consist of redness, edema (swelling) of the conjunctiva, itching, and increased lacrimation. If this is combined with rhinitis, the condition is termed allergic rhinoconjunctivitis (ARC).

<span class="mw-page-title-main">Profilin</span> Actin-binding protein

Profilin is an actin-binding protein involved in the dynamic turnover and reconstruction of the actin cytoskeleton. It is found in most eukaryotic organisms. Profilin is important for spatially and temporally controlled growth of actin microfilaments, which is an essential process in cellular locomotion and cell shape changes. This restructuring of the actin cytoskeleton is essential for processes such as organ development, wound healing, and the hunting down of infectious intruders by cells of the immune system.

<span class="mw-page-title-main">Soy allergy</span> Type of food allergy caused by soy

Soy allergy is a type of food allergy. It is a hypersensitivity to ingesting compounds in soy, causing an overreaction of the immune system, typically with physical symptoms, such as gastrointestinal discomfort, respiratory distress, or a skin reaction. Soy is among the eight most common foods inducing allergic reactions in children and adults. It has a prevalence of about 0.3% in the general population.

<span class="mw-page-title-main">Allergic contact dermatitis</span> Inflammation of the skin due to contact with an allergen

Allergic contact dermatitis (ACD) is a form of contact dermatitis that is the manifestation of an allergic response caused by contact with a substance; the other type being irritant contact dermatitis (ICD).

Cross-reactivity, in a general sense, is the reactivity of an observed agent which initiates reactions outside the main reaction expected. This has implications for any kind of test or assay, including diagnostic tests in medicine, and can be a cause of false positives. In immunology, the definition of cross-reactivity refers specifically to the reaction of the immune system to antigens. There can be cross-reactivity between the immune system and the antigens of two different pathogens, or between one pathogen and proteins on non-pathogens, which in some cases can be the cause of allergies.

<span class="mw-page-title-main">Foam latex</span> Form of latex containing bubbles

Foam latex or latex foam rubber is a lightweight form of latex containing bubbles known as cells, created from liquid latex. The foam is generally created though the Dunlop or Talalay process in which a liquid latex is foamed and then cured in a mold to extract the foam.

FITkit is an immunological test for measuring natural rubber latex (NRL) allergens from a variety of rubber products, such as gloves.

Vytex Natural Rubber Latex (NRL) is a brand of natural rubber latex produced and marketed by Vystar Corporation. Vytex NRL is an alternative material to petroleum-based synthetics and traditional (Hevea) natural rubber latex. Protein test results show that Vytex NRL typically has 90% fewer antigenic proteins than Hevea natural rubber latex.

<span class="mw-page-title-main">Pro-hevein</span>

Pro-hevein is a wound-induced and a lectin-like protein from Hevea brasiliensis where it is involved in the coagulation of latex.

<span class="mw-page-title-main">Ara h1</span>

Ara h 1 is a seed storage protein from Arachis hypogaea (peanuts). It is a heat stable 7S vicilin-like globulin with a stable trimeric form that comprises 12-16% of the total protein in peanut extracts. Ara h 1 is known because sensitization to it was found in 95% of peanut-allergic patients from North America. In spite of this high percentage, peanut-allergic patients of European populations have fewer sensitizations to Ara h 1.

<span class="mw-page-title-main">Metal allergy</span> Medical condition

Metal allergies inflame the skin after it has been in contact with metal. They are a form of allergic contact dermatitis. They are becoming more common, as of 2021, except in areas with regulatory countermeasures.

References

  1. ↑ Wang, Hui; Yang, Lijuan; Rempel, Garry L. (2013). "Homogeneous Hydrogenation Art of Nitrile Butadiene Rubber: A Review". Polymer Reviews. 53 (2): 192–239. doi:10.1080/15583724.2013.776586. S2CID   96720306.
  2. 1 2 3 4 5 6 7 8 Anurag A. Agrawal; d Kotaro Konno (2009). "Latex: a model for understanding mechanisms, ecology, and evolution of plant defense Against herbivory". Annual Review of Ecology, Evolution, and Systematics . 40: 311–331. doi:10.1146/annurev.ecolsys.110308.120307.
  3. ↑ Paul G. Mahlberg (1993). "Laticifers: an historical perspective". The Botanical Review . 59 (1): 1–23. Bibcode:1993BotRv..59....1M. doi:10.1007/bf02856611. JSTOR   4354199. S2CID   40056337.
  4. ↑ Harper, Douglas. "latex". Online Etymology Dictionary .
  5. ↑ latex . Charlton T. Lewis and Charles Short. A Latin Dictionary on Perseus Project .
  6. 1 2 3 Stanislaw Slomkowski; José V. Alemán; Robert G. Gilbert; Michael Hess; Kazuyuki Horie; Richard G. Jones; Przemyslaw Kubisa; Ingrid Meisel; Werner Mormann; Stanisław Penczek; Robert F. T. Stepto (2011). "Terminology of polymers and polymerization processes in dispersed systems (IUPAC Recommendations 2011)" (PDF). Pure and Applied Chemistry . 83 (12): 2229–2311. doi:10.1351/PAC-REC-10-06-03. S2CID   96812603. Archived (PDF) from the original on 2013-10-20.
  7. ↑ "Taraxacum kok-saghyz". Pfaf.org. Archived from the original on 2014-03-20. Retrieved 2013-03-21.
  8. ↑ Thomas M. Lewinsohn (1991). "The geographical distribution of plant latex". Chemoecology . 2 (1): 64–68. Bibcode:1991Checo...2...64L. doi:10.1007/BF01240668. S2CID   44594197.
  9. ↑ Joseph F. James (1887). "The milkweeds". The American Naturalist . 21 (7): 605–615. doi: 10.1086/274519 . JSTOR   2451222.
  10. ↑ Buttery, R. R.; Boatman, S. G. (1976). Kozlowski, T. T. (ed.). Water Deficits and Plant Growth, Volume IV: Soil Water Measurement, Plant Responses, and Breeding for Drought Resistance. Vol. IV (1st ed.). New York, New York 10003: Academic Press, Inc. p. 252. ISBN   978-0124314269.{{cite book}}: CS1 maint: location (link)
  11. ↑ Mathews, Jennifer P. (2009). Chicle: The chewing gum of the Americas, from the ancient Maya to William Wrigley. Tucson: University of Arizona Press. ISBN   978-0-8165-2821-9.
  12. ↑ J. E. Bowers (1990). Natural Rubber-Producing Plants for the United States. Beltsville, MD: National Agricultural Library. pp.  1, 3. OCLC   28534889.
  13. ↑ Yurkovich, Dror. "Dunlop latex vs. Talalay latex". Getha. Archived from the original on 2021-04-13. Retrieved 2021-04-22.
  14. ↑ Kink and everyday life : interdisciplinary reflections on practice and portrayal. Kylo-Patrick R. Hart, Teresa Cutler-Broyles. Bingley. 2021. ISBN   978-1-83982-918-5. OCLC   1262726608. Archived from the original on 2024-06-02. Retrieved 2021-12-29.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)
  15. ↑ Akamine, Y.; Sato, S.; Kagaya, H.; Ohkubo, T.; Satoh, S.; Miura, M. (2018-04-20). "Comparison of electrochemiluminescence immunoassay and latex agglutination turbidimetric immunoassay for evaluation of everolimus blood concentrations in renal transplant patients". Journal of Clinical Pharmacy and Therapeutics. 43 (5): 675–681. doi: 10.1111/jcpt.12686 . ISSN   0269-4727. PMID   29679392.
  16. ↑ "Latex Allergy | Causes, Symptoms & Treatment". ACAAI Public Website. Archived from the original on 2019-03-24. Retrieved 2019-03-24.
  17. ↑ Anderson, Christopher D.; Daniels, Eric S. (8 May 2018). Emulsion Polymerisation and Latex Applications. iSmithers Rapra Publishing. ISBN   9781859573815. Archived from the original on 2 June 2024. Retrieved 8 May 2018– via Google Books.
  18. ↑ "Latex allergy - Symptoms and causes". mayoclinic.com. Archived from the original on 7 October 2013. Retrieved 8 May 2018.
  19. ↑ Blanco, C.; Carrillo, T.; Castillo, R.; Quiralte, J.; Cuevas, M. (October 1994). "Latex allergy: clinical features and cross-reactivity with fruits". Annals of Allergy. 73 (4): 309–314. ISSN   0003-4738. PMID   7943998.
  20. ↑ Gromek, Weronika; Kołdej, Natalia; Świtała, Szymon; Majsiak, Emilia; Kurowski, Marcin (2024-07-19). "Revisiting Latex-Fruit Syndrome after 30 Years of Research: A Comprehensive Literature Review and Description of Two Cases". Journal of Clinical Medicine. 13 (14): 4222. doi: 10.3390/jcm13144222 . ISSN   2077-0383. PMC   11278189 . PMID   39064262.
  21. ↑ Helge B. Bode; Axel Zeeck; Kirsten Plückhahn; Dieter Jendrossek (September 2000). "Physiological and Chemical Investigations into Microbial Degradation of Synthetic Poly(cis-1,4-isoprene)". Applied and Environmental Microbiology. 66 (9): 3680–3685. Bibcode:2000ApEnM..66.3680B. doi:10.1128/aem.66.9.3680-3685.2000. PMC   92206 . PMID   10966376.
  22. ↑ Rose, K.; Steinbuchel, A. (2 June 2005). "Biodegradation of Natural Rubber and Related Compounds: Recent Insights into a Hardly Understood Catabolic Capability of Microorganisms". Applied and Environmental Microbiology. 71 (6): 2803–2812. Bibcode:2005ApEnM..71.2803R. doi:10.1128/AEM.71.6.2803-2812.2005. PMC   1151847 . PMID   15932971.
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