Animal Pair Pictures

 

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ادامه نوشته

با مرگ‌آورترین عقرب جهان آشنا شوید/ فیلم

 

 عقرب‌ها از نخستین شکارچیانی هستند که پا به خشکی گذاشتند. از میان 1500 گونه عقرب شناخته‌شده در سراسر جهان، عقرب سرخ هندی مرگ‌آورترین آن‌هاست که در صورت عدم درمان گزیدگی، مصدوم خواهد مرد.

 

 

 

 

 

 عقرب‌ها یکی از نخستین شکارچیانی هستند که روی خشکی پدید آمدند. آنها توانستند از چنگ صیادان غول‌پیکری مانند دایناسورها جان به در ببرند. حدود 1500 گونه از آن‌ها تاکنون شناسایی شده و در همه‌جای زمین غیر از قطبین یافت می‌شوند. 
خوشبختانه تنها چند ده‌ گونه از این 1500 گونه برای انسان‌ها مرگ‌آورند و در میان این تعداد معدود، این کژدم سرخ هندی است که لقب مرگ‌آورترین عقرب جهان را بدست آورده است.
کژدم سرخ هندی موجودی کوچک و به‌اندازه یک فندک معمولی است، اما زهری بسیار قوی دارد. این عقرب معمولا در همان‌جایی زندگی می‌کند که انسان‌ها زندگی می‌کنند. به همین دلیل در کشورهایی مانند هند، عقرب‌گزیدگی یکی از مسایل مهم بهداشت و سلامت عمومی به شمار می‌رود و متاسفانه این کودکان هستند که بیشتر دچار این مشکل می‌شوند؛ چراکه اغلب آن‌ها پابرهنه بازی می‌کنند و نیش عقرب سرخ هندی می‌تواند به زخمی دردناک منجر شود که اگر به‌سرعت درمان نشود، احتمالا به مرگ منتهی خواهد شد. 
عقرب جزو عنکبوتیان است. این بندپای خطرناک چهار جفت پا دارد که به کمک آن‌ها راه می‌رود، دو چنگک نیز دارد که به کمک آن‌ها شکار را به دام انداخته و آن را به هنگام خوردن، ثابت نگاه می‌دارد. بخش دهان نیز غذا را می‌جود، آن‌را به مایعی لزج تبدیل کرده و به‌سمت شکم خود می‌کِشد. 
دم بند‌بند عقرب نیز به بالا خم شده و در انتهای آن، نیش و غده ترشح سم قرار گرفته است. البته این دم غیر از نیش‌زدن، وظیفه حفظ تعادل عقرب را نیز برعهده دارد. عقرب‌ها برخلاف شهرت دیرینه‌ای که دارند، از نیش خود به عنوان آخرین راهکار برای شکار استفاده می‌کنند. عقرب‌ها موجوداتی خجالتی هستند و به‌جای آن‌که به دنبال شکار بگردند، گوشه‌ای دنج را انتخاب کرده و در آن‌جا به انتظار شکار صبر می‌کنند.

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Neuroscience: Animations

X Inactivation

This animation shows how the random deactivation of one of the X chromosomes in a pair can lead to a mozaicism in the expression genes. Includes audio narration.

55 seconds
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ادامه نوشته

Genomics and Chemical Genetics: Animations

Small-Molecule Microarrays

To screen many small molecules at once, microarray technology is useful. Automated devices have made it possible for thousands of different small molecules to be printed as an array of spots on a glass slide. A single type of protein which has been tagged with a fluorescent marker can then be washed across the array. Any small molecule that binds to the protein can be detected by scanning for spots that are fluorescent.

59 seconds
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Genomics and Chemical Genetics: Animations

Myosin II Mechanism

Myosin II is one of the molecules involved in furrow formation in dividing cells. This animation shows how the molecule operates, and how furrowstatin blocks the mechanism and halts division of a cell.

57 seconds
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Sex Determination: Animations

MIX-1

This animation shows how MIX-1 facilitates both chromosome condensation and dosage compensation.

3 minutes 38 seconds
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ادامه نوشته

Sex Determination: Animations

Meiosis

Meiosis, the form of cell division unique to egg and sperm production, sets the stage for sex determination by creating sperm that carry either an X or a Y sex chromosome. But what is it about the X or Y that determines sex?

5 minutes 52 seconds
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ادامه نوشته

Sex Determination: Animations

Evolution of the Y Chromosome

How did the human Y chromosome become so small relative to its X counterpart? This animation depicts the 300-million-year odyssey of the sex chromosomes that began when the proto X and Y were an identical pair.

5 minutes 38 seconds
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ادامه نوشته

Cancer: Animations

p53

A 3D animation showing the molecule p53 binds to DNA and initiates the transcription of mRNA.

25 seconds
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ادامه نوشته

Cancer: Animations

Mismatch Repair

This animation illustrates how mistakes made during DNA replication are repaired.

1 minute 22 seconds
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ادامه نوشته

Cancer: Animations

Gleevec

Gleevec is a drug designed to interfere with the stimulation of growth in leukemia cells. This 3D animation shows how this is achieved.

1 minute 3 seconds
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ادامه نوشته

DNA: Animations

CML and Gleevec

Chronic myeloid leukemia (CML) is caused by a mutation that leads to an abnormal protein that is always active. The drug Gleevec has a shape that fits into the active site of the abnormal protein and stops its harmful effects.

41 seconds
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Cancer: Animations

Angiogenesis

A cancer tumor forms in a bed of healthy cells. The animation goes on to show how the tumor recruits blood vessels and how metastasis occurs.

1 minute 12 seconds
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ادامه نوشته

Animations : DNA replication schematic

The structure of DNA, discovered by James Watson and Francis Crick, suggests a mechanism of replication. The double helix unwinds, and each strand acts as a template for the construction of the new DNA molecule.

50 secondsPlay Large: MOV / WMV (3 MB)

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Amoeboid Sperm of C. elegans

Video closeup of the C. elegans sperm that moves like an amoeba.

10 seconds
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Diversity of Small Molecules

A molecular menagerie of small molecules is displayed, with two particular molecules singled out for attention: rapamycin and furrowstatin, which are discussed in the remainder of Dr. Schreiber's lectures on chemical genetics.

1 minute 56 seconds
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ادامه نوشته

Chemspace

The hypothetical relationship of chemical space and biological space is plotted on a three-dimensional graph, giving a glimpse of the future direction of research at the intersections of various disciplines.

1 minute 34 seconds
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ادامه نوشته

Cellular Screening

One technique for discovering small molecules of biological relevance is to expose cultured cells to a variety of small molecules and look for changes in the cells' appearance, behavior or other measurable qualities.

1 minute 30 seconds
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ادامه نوشته

Animation Mitosis in Pig Kidney Epithelial Cells

Perhaps the most recognizable phase of mitosis is termed metaphase, a stage where the chromosomes, attached to the kinetochore microtubules, begin to align in a single plane (known as the metaphase plate) midway between the spindle poles. The kinetochore microtubules exert tension on the chromosomes, which move back and forth in rapid erratic motion as a result, and the entire spindle-chromosome complex is now ready for the next event, separation of the daughter chromatids. Metaphase, one of the most critical stages in mitosis, occupies a substantial portion of the division cycle. In the digital videos presented above, normal pig kidney (LLC-PK1 line) epithelial cells labeled with mEmerald fluorescent protein fused to microtubule EB3 (a protein that binds to the positive ends of microtubules) and mCherry fused to human histone H2B (highlighting the chromosomes) are visualized undergoing mitosis in laser scanning confocal microscopy. for Download animation click Part 1,2,3,4,5,6,7,8,9,10,11,12,13

Part 1 Part 2 Part 3 Part 4 Part 5 Part 6 Part 7

 Part 8 Part 9 Part 10 Part 11 Part 12 Part 13  

Cloning an Army of T Cells for Immune Defense

این انیمیشن نحوه تکثیر سلولهای T در بدن را نشان می دهد. برای دانلود بروی Genetics Molecular کلیک کنید. توضیحات در رابطه با انیمیشن به انگلیسی .

Cloning an Army of T Cells for Immune Defense

View the animation to see how one type of immune cell—the helper T cell—interprets a message presented at the surface of the cell membrane. The message is an antigen, a protein fragment taken from an invading microbe. A series of events unfolds that results in the production of many clones of the helper T cell. These identical T cells can serve as a brigade forming an essential communication network to activate B cells, which make antibodies that will specifically attack the activating antigen

Introduction

The cells of our immune system discover and destroy foreign invaders that enter our bodies and may threaten our health. Among the invaders are viruses, bacteria, and other microscopic pathogens. Pathogens are recognized by the immune system as not being part of the body, as "non-self." The immune system probes specific proteins on the surface of invading microbes, first recognizing the proteins as foreign and then coordinating their destruction by a variety of strategies, including producing antibodies and engulfing foreign cells

Immune-system cells defend our bodies by acting as a coordinated team. This cellular defense team communicates in precise, highly regulated ways. Specific molecules on their surfaces mediate the communication among immune system cells. Although highly specific, the interactions and responses of the immune system depend on chance meetings of cells in the fluid spaces of the lymphatic system and circulatory system

View the animation to see how one type of immune cell—the helper T cell—interprets a message presented at the surface of the cell membrane. The message is an antigen, a protein fragment taken from an invading microbe. A series of events unfolds that results in the production of many clones of the helper T cell. These identical T cells can serve as a brigade forming an essential communication network to activate B cells, which make antibodies that will specifically attack the activating antigen

The animation illustrates several fundamental biological principles and processes common to many cellular functions. It may be helpful to view the animation several times, first to gain a general impression of the signal transduction process and then to focus on particular molecular details

Four main themes emerge

Signal transduction. Molecular information is presented at the surface of the T cell. The molecular message is then processed within the T cell through a complex cascade of molecular interactions called signal transduction. The molecular cascade stimulates a reaction in the receiving T cell: the production of specific receptors and extracellular signaling molecules

 

Signal amplification. When a cell processes a message, it often also amplifies that message. At each step in the molecular cascade, the signal may become stronger. In the case of the T cell, it will release many molecules of the protein interleukin-2 (IL-2) and produce many IL-2 receptors, and in the end, many thousands of identical T cells will be produced

Molecular switching. Slight changes to the state or shape of a protein can convey information or trigger a cellular process. Molecules can be turned on and off through molecular switches. Adding and removing a phosphate group—called phosphorylation and dephosphorylation, respectively—are important and common examples of changes that can flip a molecular switch

Molecular specificity. Molecules interact with one another in specific ways. Enzymes will only work on certain substrate molecules. Receptors will only bind certain ligands. Only specific sets of molecules will associate to form molecular complexes or gather at particular docking sites to do their job

Genetics Molecular

 

Sanger method of DNA sequencing

این فیلم نحوه توالی یابی DNA با روشSanger را نشان مي دهد براي دانلود روي genetics molecular كليك كنيد

Sanger method of DNA sequencing

Fred Sanger developed the first technique for sequencing DNA. DNA is replicated in the presence of chemically altered versions of the A, C, G, and T bases. These bases stop the replication process when they are incorporated into the growing strand of DNA, resulting in varying lengths of short DNA. These short DNA strands are ordered by size, and by reading the end letters from the shortest to the longest piece, the whole sequence of the original DNA is revealed

Genetics Molecular

mRNA splicing

اين فيلم چگونگي فرايند ويرايش mRNA ، حذف اينترون ها و باقي ماندن اگزونها را نشان مي دهد براي دانلود روي Genetics Molecular كليك كنيد

mRNA splicing

Once a gene has been transcribed into messenger RNA (mRNA), it is edited in a process called splicing. Noncoding regions called introns are removed, leaving protein-coding regions called exons

Genetics Molecular

Human genome sequencing

اين انيميشن درباره پروژه تعيين توالي ژنوم انسان است براي دانلود روي genetics molecular كليك كنيد.

توضيحات درباره انيميشن به زبان انگليسي

The public Human Genome Project started by identifying unique marker sequences distributed throughout the genome. Then, many copies of a small section of DNA were randomly cleaved into smaller fragments, and each small fragment was sequenced. Because there were originally many copies of the DNA in question, many fragments represented the same part of the genome. These were aligned by identifying overlapping regions of the sequence, and then they were assembled into the original DNA

GENETICS MOLECULAR