Jan-Jung Li

Spatial and temporal variation of coral recruitment in Taiwan

1: Institute of Marine Biology, National Sun Yat-sen University, Kaohsiung, Taiwan 2: National Museum of Marine Biology & Aquarium, Pingtung, Taiwan 3: Institute of Zoology, Academic Sinica, Taipei, Taiwan 4: Institute of Oceanography, National Taiwan University, Taipei, Taiwan 5: Kenting National Park Authority, Pingtung, Taiwan 6: Penghu Aquarium, Taiwanese Fisheries Research Institute, Penghu, Taiwan

Natural product chemistry of gorgonian corals of the genus Junceella

The structures, names, and references of 49 secondary metabolites from the gorgonian corals of genus Junceella are described in this review.

Why selection favors protandrous sex change for the parasitic isopod, Ichthyoxenus fushanensis (Isopoda: Cymothoidae)

A flesh burrowing parasitic isopod, Ichthyoxenus fushanensis, was found infecting the body cavity of a freshwater fish, Varicorhinus bacbatulus, in pairs. The marked sexual size dimorphism, with much larger females than males, and the presence of penes vestige on mature females suggest a protandrous sex change in I. fushanensis. Here we investigate the question of why selection favors protandrous sex change for I. fushanensis, by analyzing the interactions among clutch size, female size, male size, and their host size. The number of manca, the first free-living juvenile stage released, per brood was closely related to the size of the female. Excluding the effects of interaction among causal variables, the negative correlation of male size alone on clutch size suggests that a small male did not limit an individuals mating and fertilization success. When the effect of host size is removed statistically, there exists a significant negative relationship between the sizes of paired males and females. This indicates that the resources available from host fish are limited, and that competition exists between paired male and female resulting in a trade-off of body size. Due to the very low success rate of hunting for a host of mancas, a female with larger body size and higher fecundity has a fitness advantage. To augment the clutch size, a productive combination is a smaller male and a larger female in a host. The constraints of the limited resources and the trade-off between the sizes of paired male and female may favor I. fushanensis to adopt the reproductive strategy of protandrous sex change resulting in a larger female and hence more mancas. The pattern of the interactions among male, female, and the number of mancas, may be considered as a selective force for I. fushanensis protandrous sex change, where the available resources are constrained by the size of the host.

Secondary Metabolites from the Soft Coral Sinularia arborea

Two new 13-hydroxycembrane diterpenoids, arbolides A (1) and B (2), along with a known trihydroxysteroid, crassarosterol A (3), were isolated from the soft coral Sinularia arborea. The structures of new cembranes 1 and 2 were elucidated by spectroscopic methods. Steroid 3 was found to exhibit cytotoxicity toward K562 and MOLT-4 leukemia.

Isokobusone, a caryophyllane-type Norsesquiterpenoid from the Gorgonian Coral Rumphella antipathies (Gorgoniidae)

Chemical investigation of the organic extract of the gorgonian coral Rumphella antipathies furnished a 14C caryophyllane-type norsesquiterpenoid, isokobusone (1). The structure of 1 was established on the basis of spectroscopic evidence, particularly from 1D and 2D NMR experiments. Isokobusone (1) staphylococcus aureus.

Is Large Body Size always Advantageous for Terrestrial Adaptation

Sesarmops intermedium de Haan (1835) is a semi-terrestrial crab inhabiting the areas around a forest creek at Heng-chun Peninsula in southern Taiwan. Small and large individuals excavate tunnels near the waterline, while those individuals with medium body size are more distant from the water. This unusual distribution pattern might reflect the habitat preference related to physiological requirement of crabs with different body sizes. In natural conditions, the animals keep their haemolymph osmolality at a relatively low level near those of fully-rehydrated individuals. In dehydrated conditions, the haemolymph osmolality of the animal was much higher and was negatively related to the body size. Both the rates of water loss and uptake decrease with increasing body size. While, both the potential time exposed in air and the rehydration time increase with increasing body size. The low water loss rate of large individuals may prolong the potential time exposed in air, but this advantage may be offset by their low efficiency in water uptake simultaneously. Small crabs, with a high water uptake rate and a small amount of water requirement, may have a shorter time needed for rehydration. However, those small crabs, smaller than about 2 g in living weight, due to their extremely fast loss of body water, have to access water more frequently and thus have a lower potential for terrestrial activity also. For medium sized crabs, the advantages of high water uptake rate, less water requirement and better ability to utilize interstitial water may allow them to emancipate from the water body. Due to the constraints of performance in water balance, the optimum size for extending terrestrial activity of S. intermedium is below 14 g in weight (=28.5 mm in carapace width) at which the crabs may have a higher potential for terrestrial activity. In the terrestrial adaptation regarding the water balance of S. intermedium, how to increase water uptake efficiency and the capability to use various interstitial water on land seem to be more important than how to reduce the water loss rate. Large body size and hence the low water loss rate may not be always advantageous for the terrestrial adaptation of S. intermedium and possibly other crustaceans.