Harmonized supramolecular motility machinery and its diversity

Eukaryote number of click：316
Pollen tube attraction by the synergid cell

Species name:Torenia fournieri

ITbM, Nagoya Univ　Tetsuya Higashiyama

In the evolution of flowering plants, genes necessary for flagella formation including flagellar dyneins were lost. Non-motile sperm cells of flowering plants are conveyed by a tip-growing haploid cell, the pollen tube. The sperm cell is enclosed by an endocytic membrane of the pollen tube cell and delivered to female gametes rapidly without much water for swimming. How does the pollen tube precisely arrive at an egg-containing tissue? Pollen tube attractants had been searched for more than 140 years. The attractants were finally identified in a unique plant species, Torenia, which has a protruding egg-containing tissue. Pollen tube attraction can be directly observed in Torenia as shown in this movie. Two synergid cells on the side of the egg cell were shown to be the source of the attraction signal. Finally, two cysteine-rich peptides named LUREs were identified as true pollen tube attractants.

Molecule and Protein number of click：164
Movement of Actin-associated Myosin-II (Cross-Bridge) during Muscle Contraction

Species name:Rabbit

Osaka City Univ　Eisaku KATAYAMA

The first part of the movie indicates the movement of individual myosin-head (crossbridge), based on conventional "Tilting-Leverarm Hypothesis". Such movement was proposed from the characteristic features of the atomic models of myosin-S1 in the absence and the presence of ATP, together with the well-known experimental evidence that "the motor-domain does not appreciably rotate during the Power-Stroke". Hence, this hypothesis claims that the Power-Stroke is essentially the transition between strongly actin-bound rigor-structure (1DFK: lever-arm is extended) and ATP-bound kinked structure (1DFL). If the motor-domain is immobilized on actin, the lever-arm moiety should swing along the actin filament, The latter half of the movie exhibits the revised crossbridge-cycle we have proposed according to our direct observation of in vitro sliding actomyosin by Quick-Freeze Deep-Etch Replica Electron Microscopy (Ref. 1, 2). We noticed that the actual images of actin-sliding myosin cannot be explained by the conventional hypothesis as above, suggesting the presence of a new conformer whose crystal structure is not yet reported. After extensive search, we finally found that SH1-SH2 crosslinked myosin could be a good candidate of the new conformer whose lever-arm bends to the opposite side of ATP-bound kinked structure (Ref.3-5). Since we could successfully reconstruct its low-resolution 3-D model by a new version of single-particle-analysis (Ref. 5). Taking the results of time-resolved chemical crosslinking into consideration, we revised the scheme of crossbridge-cycle including the new conformer (Ref.5). .The conformational change shown in the movie is compatible with all the images we actually observed under in vitro actin-sliding conditions. [References] 1. Katayama E. The effects of various nucleotides on the structure of actin-attached myosin subfragment-1 studied by quick-freeze deep-etch electron microscopy. J Biochem. 1989 Nov;106(5):751-70. 2: Katayama E. Quick-freeze deep-etch electron microscopy of the actin-heavy meromyosin complex during the in vitro motility assay. J Mol Biol. 1998 May 1;278(2):349-67. 3: Katayama E, Ohmori G, Baba N. Three-dimensional image analysis of myosin head in function as captured by quick-freeze deep-etch replica electron microscopy. Adv Exp Med Biol. 1998;453:37-45. 4: Katayama E, Ichise N, Yaeguchi N, Yoshizawa T, Maruta S, Baba N. Three-dimensional structural analysis of individual myosin heads under various functional states. Adv Exp Med Biol. 2003;538:295-304. 5: Kimori Y, Baba N, Katayama E. Novel configuration of a myosin II transient intermediate analogue revealed by quick-freeze deep-etch replica electron microscopy. Biochem J. 2013 Feb 15;450(1):23-35. 6. Andreev OA, Reshetnyak YK. Mechanism of formation of actomyosin interface. J Mol Biol. 2007 Jan 19;365(3):551-4.

Prokaryote number of click：163
Bacterium moves like a tank 3

Species name:Flavobacterium johnsoniae

Gakushuin University　Daisuke Nakane

Flavobacterium johnsoniae and many other members of Bacteroidetes exhibit rapid gliding motility over surfaces by a unique mechanism. These cells do not have flagella or pili; instead, they rely on a novel motility apparatus. SprB, a 669 kDa cell-surface adhesin, is required for efficient gliding. Here, we showed dynamic movements of SprB were observed by fluorescent microscopy. SprB moved at a constant speed of 2 um/s on the cell surface along a left-handed helical closed loop, appears that the cell have a moving conveyer belt. Attachment of SprB to the substratum was associated with cell movement, suggesting a model for gliding, in which adhesins are propelled along a helical track, generating rotation and translation of the cell.

Eukaryote number of click：159
Vahlkampfia

Species name:Vahlkampfia sp.

Bureau of Swerage, 　Tokyo Metropolitan Goverment

The size of Amoeba radiosa (should this be vahlkamphia?)is about 10 - 30 μm, rarely over 100 μm in length. It has along flat body and moves smoothly. Amoeba radiosa moves fastest in the group of Sarcodina and moves rapidly in one direction. Its food source is mainly bacteria.

Eukaryote number of click：158
Philodina sp.

Species name:Philodina sp.

Bureau Swerage,　Tokyo Metropolitan Government

The size of Philodina is 300-1,000 μm in length. The body is thin long. One foot with four toes. The head has two crown of chilia. The eyespots lie on the brain. It moves like leeches. It shows leech-like movement and moves around flocs. Philodina feed on algae and bacteria. It can retract cron of cilia into the body.

Eukaryote number of click：154
Drepanomonas sp.

Species name:Drepanomonas

Bureau Swerage,　Tokyo Metropolitan Government

The size of Drepanomonas is 30-40 μm in length. Its cell is uneven crescent shape. Posterior ends pointed and both side rounded. Drepanomonas has a smaller number of cilia. Its shape of body does not deform.

Eukaryote number of click：153
Synula moving along aggregate surface

Species name:Synura

AL-Museum　AL-Museum

Synula-a colony of brown flagellates- travels around an aggregate, sometimes by tumbling and sometimes by sliding along the surface of the aggregate.

Eukaryote number of click：152
Mouse tracheal cilia

Species name:Mus musculus

Hamamatsu Univ Sch Med　Koji Ikegami

Moving cilia on mouse tracheal epithelia. The beating frequency is about 10 to 20 Hz. The batch of cilia shows a wavelike motility, so-called metachronal wave.

Molecule and Protein number of click：151
Fig1bSide_Branching by Arp2/3complex with VCA

Waseda Univerisity　Shin'ichi ISHIWATA

Fig1bSide_Branching by Arp2/3complex with VCA

Eukaryote number of click：150
Trypanosoma brucei bloodstream form

Species name:Trypanosoma brucei

Institute of Cell Biology, University of Bern, Switzerland　Prof. Torsten Ochsenreiter

Trypanosoma brucei (Mitat1.1) is a single celled protozoan parasite that causes Human african trypanomiasis and Nagana in cattle. The movie is in slow motion the cells actually swim much faster. Images were captured by Dr. Torsten Ochsenreiter using a Zeiss Cell Observer Microscope (63x DIC objective) at the University of Georgia, Athens, USA.