Colpoda
Description
Colpoda are distinctly reniform (kidney shaped) and are strongly convex on one side, concave on the other. The concave side often looks like a bite was taken out of it. Although they are not as well known as the paramecium, they are often the first protozoa to appear in hay infusions , especially when the sample does not come from an existing mature source of standing water.
Considering how common Colpoda are, how important they are in the world of microbes and how easily they are cultured (just pull up some grass, including a little dirt, then add with dechlorinated water to a jar), it is amazing that they don't come up more frequently in schools. Indeed, many high school students, after completing the biology chapter on microbes, will not know a colpoda when they see one and might think it is an oddly shaped paramecium!
[edit]Habitat
Colpoda are often found in moist soil and because of their ability to readily enter protective cysts will quite frequently be found in desiccated samples of soil and vegetation[2] as well as in temporary natural pools such as tree holes.[3] They have also been found in the intestines of various animals, and can be cultured from their droppings,[4] although it is not clear that they are pathogenic. Indeed, it is generally believed that in most cases the animals ingested colpoda cysts that encrusted plants, or were contained in soil accidentally ingested and that these cysts simply passed through the digestive tract intact. This may be an important means of distribution that limits localization of colpoda populations which might otherwise lead to speciation.
Colpoda cucullus, on the other hand, has been found inhabiting the surface of plants and seems to dominate the microfauna there. It shouldn't be a surprise that several species of colpoda have been found in pitcher plants, despite the digestive enzymes.[5]
Colpoda also tend to be found in abundance where increased levels of bacteria offer an enriched food source. In Commercial chicken houses, for example, they seemed to be ubiquitous but the species found vary widely from one location to the next, suggesting that these populations represent local soil and aquatic populations which migrated into the new habitat.[6]
In addition to inhabiting a wide variety of microclimates, colpoda can be found almost everywhere around the world where there is standing water or moist soil, even where these conditions are only ephemeral. Colpoda brasiliensis for example was discovered in Brazilian floodplains in 2003.[7]Colpoda irregularis has been found in the high desert region of Southwest Idaho. Colpoda aspera has been found in the Antarctic. Colpoda are also found in the arctic where warmer temperatures and longer summers lead to greater density and species diversity.[8]
Not only is the genus widespread, there are also several species that have nearly global distribution, and, indeed, it has been suggested this may be true of all species, a fact that could be borne out by better investigation.[9] Though colpoda are not normally found in the marine environment, there are many ways they can travel from one continent to another. For example cysts can become lodged in the plumage of migratory birds, becoming dislodged hundreds or even thousands of miles away. Also, because cysts are so small and light, they can be swept by air currents into the upper atmosphere, and then come down on another continent.[10]
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Deskripsi
Colpoda yang jelas reniform (ginjal berbentuk) dan sangat cembung di satu sisi, cekung di sisi lain. Sisi cekung sering terlihat seperti gigitan diambil dari itu. Meskipun mereka tidak juga dikenal sebagai paramecium, mereka sering pertama protozoa muncul di infus hay, terutama ketika sampel tidak berasal dari sumber yang matang yang ada genangan air.
Mengingat betapa umum yang Colpoda, betapa pentingnya mereka dalam dunia mikroba dan betapa mudahnya mereka yang dibudidayakan (hanya menarik beberapa rumput, termasuk sedikit tanah, kemudian tambahkan dengan air dechlorinated ke jar), itu menakjubkan bahwa mereka don ' t datang lebih sering di sekolah. Memang, banyak siswa SMA, setelah menyelesaikan bab biologi pada mikroba, tidak akan tahu Colpoda ketika mereka melihat satu dan mungkin berpikir itu adalah paramecium berbentuk aneh!
[Sunting] Habitat
Lebih rinci gambar Colpoda berbagai ukuran di 400x
Colpoda sering ditemukan di tanah lembab dan karena kemampuan mereka untuk siap memasuki kista pelindung akan cukup sering ditemukan dalam sampel kering dari tanah dan vegetasi [2] serta di kolam alami sementara seperti lubang pohon [3] Mereka juga. telah ditemukan dalam usus berbagai hewan, dan dapat dibiakkan dari kotoran mereka, [4] meskipun tidak jelas apakah mereka bersifat patogen. Memang, umumnya percaya bahwa dalam kebanyakan kasus hewan tertelan kista Colpoda bahwa tanaman bertatahkan, atau yang terkandung dalam tanah sengaja tertelan dan bahwa kista ini hanya melewati saluran pencernaan utuh. Ini mungkin merupakan sarana penting yang membatasi distribusi lokalisasi populasi Colpoda yang dinyatakan mungkin menyebabkan spesiasi.
Colpoda cucullus, di sisi lain, telah ditemukan menghuni permukaan tanaman dan tampaknya mendominasi mikrofauna sana. Seharusnya tidak mengherankan bahwa beberapa spesies Colpoda telah ditemukan pada tanaman pitcher, meskipun enzim pencernaan. [5]
Colpoda juga cenderung ditemukan dalam kelimpahan di mana peningkatan tingkat bakteri menawarkan sumber makanan yang diperkaya. Di rumah-rumah ayam Komersial, misalnya, mereka tampaknya di mana-mana, tetapi spesies yang ditemukan bervariasi dari satu lokasi ke lokasi berikutnya, menunjukkan bahwa populasi ini merupakan tanah lokal dan populasi air yang bermigrasi ke habitat baru. [6]
Selain menghuni berbagai microclimates, Colpoda dapat ditemukan hampir di mana-mana di seluruh dunia di mana ada genangan air atau tanah lembab, bahkan di mana kondisi ini hanya berlangsung sebentar saja. Colpoda brasiliensis misalnya ditemukan di dataran banjir Brasil pada tahun 2003. [7] Colpoda irregularis telah ditemukan di wilayah gurun tinggi Southwest Idaho. Colpoda aspera telah ditemukan di Antartika. Colpoda juga ditemukan di Arktik di mana suhu hangat dan musim panas lebih lama menyebabkan kepadatan yang lebih besar dan keragaman spesies. [8]
Tidak hanya adalah genus luas, ada juga beberapa spesies yang memiliki distribusi hampir global, dan, memang, telah menyarankan ini mungkin benar dari semua spesies, suatu fakta yang bisa dibuktikan dengan pemeriksaan penunjang yang lebih baik. [9] Meskipun Colpoda tidak biasanya ditemukan di lingkungan laut, ada banyak cara yang mereka dapat melakukan perjalanan dari satu benua ke benua lain. Misalnya kista dapat menjadi bersarang di bulu burung migran, menjadi ratusan copot atau bahkan ribuan mil jauhnya. Juga, karena kista sangat kecil dan ringan, mereka dapat tersapu oleh arus udara ke atmosfer atas, dan kemudian turun di benua lain. [10]
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