Nature Cell Biology dergisinde yayımlanan makalede, CHIP enziminin, kansere yol açan proteinlerin sayısını azaltarak, hastalığın yayılmasını önleyebildiği belirtildi.

Bilim adamları, farelere, biri CHIP enzimi taşıyan, diğeriyse taşımayan iki çeşit insan meme kanseri hücresi zerk ettiler.

Araştırma sonunda, CHIP enzimli hücrelerin bulunduğu farelerdeki tümörün, enzimin bulunmadığı farelere oranla çok daha küçük olduğu belirlendi.

Araştırmayı yapanlardan Junn Yanagisawa, “Vardığımız sonuç, CHIP proteininin meme tümörünün büyümesini ve metastazı önlediğidir” dedi.

Meme kanseri tedavisinde, tümördeki CHIP proteini seviyesini ölçmenin, tedavi açısında önemli bir bilgi sağlayacağını belirten Yanagisawa, “Dahası, CHIP proteini seviyesini ve faaliyetini artıran yeni bir tedavi yöntemi bulunabilir” dedi.

not :Meme kanseri, akciğer kanserinden sonra en yaygın kanser türü.

 

KINGDOM ANIMALIA: ANIMALS

Phylum Porifera – sponges

Phylum Cnidaria – corals, sea anemones, hydroids, jellyfish

Phylum Ctenophora – sea gooseberries, comb jellies

Phylum Platyhelminthes – flatworms, tapeworms

Phylum Nemertea – ribbon worms, proboscis worms

Phylum Nematoda – round worms, hook worms

Phylum Echiura – spoon worms, innkeeper worms

Phylum Sipuncula – peanut worms

Phylum Mollusca – snails, clams, mussels, octopus, squid

Phylum Annelida – segmented worms, leeches

Phylum Arthropoda – crustaceans, insects, spiders, centipedes

Phylum Phoronida – horseshoe worms

Phylum Bryozoa – lace corals, moss animals

Phylum Brachiopoda – lamp shells

Phylum Chaetognatha – arrow worms

Phylum Hemichordata – acorn worms

Phylum Echinodermata – starfish, urchins, sea cucumbers, sea lilies

Phylum Chordata – fish, birds, mammals, tunicates, lancelets

SEAWEEDS

KINGDOM PLANTAE – PLANTS

Phylum Chlorophyta – green algae, stoneworts

Phylum Rhodophyta – red seaweeds, red algae

KINGDOM CHROMISTA – BROWN & YELLOW SEAWEEDS, DIATOMS

Phylum Ochrophyta

Phylum Bacillariophyta – diatoms

MARINE AND COASTAL FLOWERING PLANTS

Phylum Angiospermophyta – flowering plants

LICHENS

 

Characteristics of Phylum Coelenterata(CNIDARIA)

Phylum coelenterata characteristics

1. Dipoblastic body with two layers of cells, outer layer called ectoderm or epidermis and the inner layer known as the endoderm or gastrodermis.

2. Phylum coelenterata characteristics is they have a single opening into the body which acts as both the mouth and anus which functions in taking food and expelling wastes.

3. Coelenterates contain body cavity known as the coelenteron, where the digestion of food occurs. The name coelenterata for these animals is coined due to this character.

4. Existance as tubular sessile polyp forms and swimming medusa forms is also phylum coelenterata characteristics.

5. Polyp bodies often contain exoskeleton and endoskeleton.

6. These skeletons are generally composed of minerals like calcium carbonate.

7. Medusae generally have only hydrostatic skeletons.

8. Coelenterates are generally carnivorous in nature, except some species, such as coral, that get some of their food from special symbionts living within them.

9. They lack such sensory organs like eyes.

10. They hunt food passively i.e., they just wave their tentacles and when prey does come in contact with the tentacles using special structures known as nematocysts either inject a toxin that paralyses and/or kills the prey, or entangles the prey.

11. Nematocyst is common in all coelenterates is phylum coelenterata characteristics and is one of major trait that distinguishes this phylum from the others. Also contains structures called spirocysts and ptychocysts.

12. The mouth lining of coelenterates are known as cnidae the phylum coelenterata characteristics, which is how this phylum is named currently.

13. All coelenterates are aquatic and mostly are marine in nature, found from the shallow water to the depths of the abyss. Some species of the class hydrozoans are found in freshwater ponds and lakes.

14. The phylum is divided in to 4 major classes namely, anthozoa, cubozoa, hydrozoa, and scyphozoan.

PHYLUM CNIDARIA

Posted: 16 Kasım 2010 in Genel

Kingdom Animalia
PHYLUM CNIDARIA – Radially symmetric animals

INTRODUCTION:

The phylum Cnidaria is considered. by most zoologists to have diverged from the kingdom Protista independently of the phylum Porifera. Members of this phylum are considered to be more “advanced” than the poriferans for two major reasons. First, they are the first to show tissue level organization, although they have no organs. Second, the adult forms are derived from two distinct embryonic germ layers, the ectoderm and the endoderm (they are diploblastic). Higher phyla are triploblastic (derived from three distinct embryonic germ layers).

The organisms in the phylum Cnidaria are characterized by exhibiting radial symmetry. Terms for direction, therefore, use the mouth as a point of reference. The end of the organism which contains the mouth is the oral end; the opposite end of the animal is termed aboral. Radial symmetry refers to the fact that any plane passing through the oral-aboral axis divides the animal into two equal halves, each a mirror image of the other.

The basic body plan of the cnidarians is a sac-like structure, with an internal cavity called the gastrovascular cavity. The gastrovascular cavity has a single opening which serves as both mouth and anus, which is often surrounded by tentacles. The body wall has an external cell layer, the epidermis; an internal cell layer, the gastrodermis that lines the gastrovascular cavity; and a layer between the other two, called the mesoglea which may be either cellular, or more often, a cellular. Unique organelles, called nematocysts are found in cells called cnidoblasts. Cnidoblasts are especially abundant on tentacles, but may be generally distributed throughout the epidermis and gastrodermis.

The life cycle of a typical cnidarian alternates between an often sessile polyp stage and a free-swimming medusa stage. The existence of two distinct forms such as this is known as polymorphism. Both stages exhibit the body plan described above; however, the polyp stage is cylindrical and attached at the aboral end to a substrate, while the medusa stage is flattened in appearance with the mouth oriented downward. The polyp stage is an asexual stage, while the medusa is a sexual stage. In some cnidarian classes, either the polyp or the medusa stage may be reduced or completely absent.

Anthozoa.
In this exercise you will examine the three classes of Cnidaria – Hydrozoa, Scyphozoa, and Anthozoa.

PROCEDURE:

CLASS HYDROZOA – Members of this class include the genera Hydra, Obelia, and Gonionemus. Most members of this class exhibit both the polyp and medusa stages; however, Hydra exists only in the polyp form

Hydra

1. Obtain a live specimen of Hydra and observe it under a dissecting microscope. Draw the specimen, labeling the body stalk and the tentacles. Place the specimen on a microscope slide with a drop of methylene blue. Place a cover slip over the specimen and apply GENTLE pressure to the cover slip. Observe the specimen again, using a compound microscope and looking for discharged nematocysts. Draw one of these structures.
Here are diagrams of an undischarged and discharged nematocyst.

Obelia

2. Examine a whole mount of part of a colony under a dissecting microscope or low power of a compound microscope. Sketch the specimen and label:

a. the hydrocaulus, (main, stalk-like stem) and the perisarc (a transparent, noncellular covering of the stem)
b. a hydranth (feeding polyp) and its tentacles
c. a gonangium (reproductive polyp), and medusa bud

An Obelia medusa can be viewed here.

Gonionemus

3. Place a Gonionemus medusa in a watch glass and examine its structure under a dissecting microscope. See if you can tell “which end is up”,that is, locate the upper or convex surface, the exumbrella, and the concave subumbrella. Sketch the specimen, labeling:

a. the velum – a circular shelf-like rim attached to the margin of the umbrella and directed inward
b. the manubrium – a dark-colored projection hanging down from the center of the subumbrella cavity. The free end is the mouth.
C. the ring canal, which runs around the circumference of the umbrella
d. the four radial canals, which extend to the margin of the umbrella and connect with the ring canal
e. the tentacles, which arise from the umbrella margin
f. the statocysts (organs of balance), located between the bases of the tentacles
g. the gonads- folded, ribbon-like structures suspended beneath the radial canals


CLASS SCYPHOZOA – Animals in this class are entirely marine. The polyp stage is reduced or absent.

Aurelia

4. Obtain and observe a preserved specimen of Aurelia. Compare Aurelia with Gonionemus. Note the absence of a velum.

CLASS ANTHOZOA – the term anthozoa literally means “flowering animals” in reference to the brightly colored forms exhibited by some members of this class. They exist in the sessile polyp stage only; no medusa stage is present. The class Anthozoa is a large class whose representatives include the sea anemone and sea coral.

Metridium

5. Examine a specimen of the sea anemone Metridium. Draw the specimen and label:

a. the oral disc and the tentacles attached to it
b. the mouth (the opening in the oral disc) – the mouth leads into a gullet which is a passageway leading into the gastrovascular cavity
c. the pedal disc (basal disc), which is the point of attachment to the substrate


Sponges ( Sponges fall into 3 groups based on body organization)

1)Asconoids;are small , simple forms with a tube-shaped body

2)Syconoids;also have a tubular body whose wall is much thicker and highly folded into a series of incurrent canals that deliver water into radial canals lined with choanocytes.

3)Leuconoid:the largest and most complex ones
-permits for an increase in body size

ntroduction to Phylum Porifera
The Sponges

"Sponges are the simplest multicellular animals. Because the cell is the elementary unit of life, the evolution of organisms larger than unicellular protozoa arose as an aggregate of such building units. There are many advantages to multicellularity as opposed to simply increasing the mass of a single cell. Since it is at cell surfaces that exchange takes place, dividing a mass into smaller units greatly increases the surface area available for metabolic activities. Thus multicellularity is a highly adaptive path toward increasing body size."

Major Characteristics of Phylum Porifera

Multicellular; body a loose aggregation of cells of mesenchymal origin;
Body with pores (ostia), canals, and chambers that serve for passage of water;
All aquatic; mostly marine;
Symmetry radial or none;
Epidermis of flat pinacocytes; most interior surfaces lined with flagellated collar cells (choanocytes) that create water currents; a gelatinous protein matrix called mesoglea contains amebocytes, collencytes, and skeletal elements;
Skeletal structure of fibrillar collagen (a protein) and calcareous or siliceous crystalline spicules, often combined with variously modified collagen (spongin) fibrils;
No organs or true tissues; digestion intracellular; excretion and respiration by diffusion;
Reactions to stimuli apparently local and independent; nervous system probably absent;
All adults sessile and attached to substratum;
Asexual reproduction by buds or gemmules and sexual reproduction by eggs and sperm; free-swimming ciliated larvae.
Sponges are differentiated by the type of canal system

Asconoids – Small and tube shaped. Water enters through microscopic dermal pores into a large cavity called the spongocoel, which is lined with choanocytes. The choanocyte flagella pull the water through the pores and expel it through the single osculum.
Syconoids – Syconoid sponges also have a tubular body and single osculum, but the body wall is thicker and more complex. Water enters through incurrent canals that deliver it to radial canals, which are lined with choanocytes. The radial canals then empty into the spongocoel, which is lined with epithelial cells and not with choanocytes.
Leuconoids – Leuconoid sponges have the most complexity and are the best adapted for increase in sponge size. Most leuconoids form large colonial masses, each member of the mass having its own osculum, but individual members are poorly defined and often impossible to distinguish. Clusters of flagellated chambers are filled from incurrent canals and discharge water into excurrent canalsosculum. that eventually lead to the
So now students, these are the detail notes of Porifera for your HSEB exams. Read it carefully and post your suggestions.

First Aristotle observed them.
John Ellis in 1765 recognised them as animals. In 1825 Robert Grant gave them the name Porifera.
Habit: they are low multicellular, cellular level, no tissue, marine, few freshwater, all aquatic, solitary or colonial, all sessile.
Body form: vase like (Scypha), cylindrical (Leucosolenia), tubular or cushion shaped.
Symmetry: radial or asymmetrical.
External morphology: body perforated by pores, ostia, and an exhalant osculum having oscular fringe, body wall has oxeotes or spicules. A central cavity spongocoel or paragastric cavity is present.
Body wall: Diploblastic, with outer pinacoderm and inner choanoderm enclosing gelatinous non cellular mesenchyme having skeletal elements and free amoeboid cells.
Canal system: this is complex system of pores and canals; body wall is folded forming alternating invaginations and evaginations. Various components are- ostia or dermal pores, myocytes can reduce pores. Incurrent canals (invaginated folds of body wall) end blindly at inner ends. Pinacocytes line them.
Prosopyles- incurrent canal communicated with radial canals through intercellular spaces known as prosopyles.

Radial canals- corresponding evaginations, lined by flagellated choanocytes. Incurrent and radial canals are parallel.

Apopyles- opening of radial canals into spongocoel.

Spongocoel, central cavity is lined by choanocytes (Leucosolenia), not lined (Scypha).
osculum is provided with spincters( lined by myocytes)
Example in Geodia apopyle is drawn out as a narrow canal- aphodus.
In Oscarella, prosopyle is drawn out as a narrow canal- prosodus.

Canal system: these are of three types:

I. Ascon type: in Leucosolenia. Incurrent pores/ostia→through mesenchyme→lead into spongocoel (lined by coanocytes) →open outside by osculum.
II. Sycon type: in Scypha/ Sycon, this is folded version. Incurrent canal, parallel to each other, dermal ostia→incurrent canal (on flagellated) →prosopyles (intercellular species) →radial canal (flagellated) →apopyles→spongocoel→osculum.
III. Leucon type/ rhagon type: in Spongilla, further folding, flagellated chambers are small and spherical cavities, excurrent canal are developed. Ostia–incurrent canals (not lined by choanocytes) →prosopyle→flagellated chambers (lined by choanocytes) → excurrent canals (much developed) →osculum (out). Spongocoel reduced and branches as excurrent canals.
Cellular organization- there is 2 cell layers:

pinacoderm- this is divided into –
a) Exopinnacoderm- covering entire body except ostia and osculum.
b) Endopinacoderm- lining of incurrent canals and spongocoel.
Pinacoderm has Pinacocytes.

Choanoderm- called gastral epithelium, collar cells/ choanocytes, arranged loosely over mesenchyme, cells have single nucleus, one or two contractile vacuole, food vacuole, reserve food, blepharoplast, rhizoplast, and a single basal granule or kinetosome from which originate a flagellum, surrounded at its base by thin cytoplasmic collar.

Mesenchyme/ mesohyle- contain many amoebocytes which are modified archeocytes.

They are of following types:

a) Archeocytes- undifferentiated, blunt pseudopodia, large nucleus, produce other cells, sex cells, role in regeneration, totipotent.
b) Collenocytes- branching pseudopodia, united into syncytial network, are connective tissue or collencyte.
c) Chromocyte- has pigment with lobose pseudopodia.
d) Thesocyte- food reserve, storage cells, lobose pseudopodia.
e) Myocytes- contractile around ostia,
f) Scleroblast- manufactures spicules and according to nature of products are called calcoblast, silicoblast and spongioblast.
g) Germ cells- ova and sperms.
Skeleton- in mesenchyme, secreted by sclerocytes produced by Scleroblast, known as spicules.

Spicules- are crystalline, spine or rays radiate from a point, have a core organic material around which deposited either calcium carbonate (calcite) or colloidal silica. So two types, calcareous and siliceous.

Larger spicules – megascleres.

Smaller spicules-microscleres.

On the basis of number of axes-

a) Monoaxon- grows along one axes. In one direction only-monoactinal, if in both directions- diactinal. Both are calcareous and siliceous.
b) Tetraxon- four rays pointed in different directions (usually one ray is elongated), when all rays are equal, known as calthrops. When all four rays persists, known as tetraradiate/ quadriradiate. When one ray is lost, then called triradiate.
c) Triaxon- 3 axes cross one another at right angle to produce six rays, thus known as hexactinal( class hexactinellida)
d) Polyaxon- several equal rays are radiating from a central point, star like.

Development: secreted by sclerocyte- a monoaxon spicule ex- is secreted by a group of two sclerocytes, one thickener cell, other founder cell, thickener cell lays down CaCO3

Spongin-organic, horny, elastic, scleroprotein, containing sulphur and chemically related to collagen, insoluble, chemically inert, resistant to protein digestion.

Nutrition: filter feeder, by collar cells, form food vacuoles, digestion intracellular, first acidic then alkaline, amoebocyte distribute food, food is stored in thesocytes.

No respiratory, no excretory system. Contractile vacuoles in some freshwater forms help in excretion. Largely ammonia is excretory product.

Reproduction: both asexual as well sexual

asexual: following type;
a) Budding – numerous archeocytes collect at surface of pinacoderm bulges out to form bud.
b) Fission- hypertrophied over a limited area, disconnected.
c) Reduction bodies- many marine and freshwater sponge disintegrate, leaving small rounded balls, known as reduction bodies, consists of internal mass of amoebocytes covered externally by pinacoderm.
d) Gemmule- these are internal buds, unfavorable conditions, formed by aggregation of archeocytes, which secrete thick hard chitinous inner and thin outer membranes, scleroblasts secrete siliceous spicules, monaxons or amphidiscs(laid radially) between two membranes. Membrane is pierced at one end for outlet known as micropyle.
Sexual reproduction- hermaphrodite, sperm and ova derived from archeocytes or choanocytes which undergo gametogenesis, protogyny (Scypha). Cross fertilization and internal fertilization.

Spermatogonium (enlarged archeocytes) surrounded by one or more flattened cover cells to produce spermatocyst.

Oocyte moves like an amoebocyte and grows by engulfing other cells which may be amoebocytes or special nurse cells (trophocytes), undergo two maturation division to form ovum, lying in wall of radial canal.

Spermatozoa enter first a choanocytes which lies adjacent to a ripe ovum, looses tail, and swollen head becomes surrounded by capsule, choanocytes also becomes amoeboid (known as carrier cells), carrier is received by invagination of egg, sperm head penetrates into egg.

Embryogeny: cleavage- zygote begins development in mesenchyme, equal and holoblastic cleavage, first three divisions are vertical resulting into 8 blastomeres, 4th division is horizontal, forms 16 blastomeres formed, tier of 8 cells macromers( form pinacoderm) and other tier, micromere form choanoderm, micromeres undergo rapid mitosis, forming several micromeres that acquire flagella at their inner sides, now called blastula with a blastocoel, also called stomoblastula or coeloblastula, this under go inversion(turns out through mouth), so flagella are directed towards outside, now known as amphiblastula, micromeres at anterior part. Amphiblastula passes out, swims, and settles, macromers multiply rapidly, flagellated half of larva invaginated into and overgrown by granular non flagellated half, becomes a typical double walled gastrula with a blastopore at the invaginated side.

Post larval period or metamorphosis- larva fixes to substratum by its blastoporal end and lengthens into a cylinder, at free distal end of which opens osculum. Several performations become ostia, outer non flagellated granular cells gives rise to dermal epithelium or exopinnacoderm and to scleroblasts and porocytes. Inner flagellated cells develop choanoderm and give rise to functional choanocytes, archaeocytes and other amoebocytes. Mesenchyme cells are thus derived from both embryonic layers.

Sponges have high power of regeneration.

e.g. Euplectella- Venus flower baskets

Hylonema – glass rope, glass sponge

Cliona- boring sponge

Chalina- dead man’s finger or mermaid’s gloves

Euspongia- bath sponge

Spongilla- fresh water sponge.

Classification

On basis of skeleton, 3 classes

Class 1. Calcarea or calcispongeae

i. Calcareous spicules.
ii. Spicule are monoaxon, triaxon, tetra axon
E.g. Leucosolenia, Sycon or Scypha, Grantia

Leucosolenia

Class 2. Hexactinellida or hyalospongiae

i. Skeleton of siliceous spicules are triaxon or six rayed.
e.g. Euplectella, Hylonema

Euplectella

Class 3. Demospongeae

ii. Skeleton of spongin fibre or spongy fibre with siliceous spicules or skeleton may be absent.
iii. Spicules either monoaxon or tetra axon (may be 8 rayed but never 6 rayed.E.g. Euspongia, Spongilla, Cliona, Chalina.

demosponage

Class Calcarea
Class Demospangiae
Class Hexactinellida

Merhaba dünya!

Posted: 16 Kasım 2010 in Genel

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