Changes in sperm motility in response to osmolality/Ca2+ in three Indonesian fresh water teleosts: goby (Oxyeleotris marmorata), Java carp (Puntius javanicus), and catfish (Clarias batrachus)

Sperm of most fresh water teleosts become motile when released into the hypotonic fresh water environment, but the role of osmolality and Ca2+ on sperm motility is not clear. Osmotic pressure and Ca2+ concentrations increase from fresh water to brackish water. Java carp Puntius javanicus and catfish Clarias batrachus live and reproduce only in fresh water. On the other hand, goby Oxyeleotris marmorata can acclimate and reproduce from fresh water to brackish water. In the present study, sperm motility and trajectory were compared among these three Indonesian endemic species. Sperm of Java carp, goby, and catfish begun to move in the hypotonic condition (< 200 mOsm/kg). However, the response to Ca2+ was different among these teleosts. In the presence of Ca2+, Java carp sperm swam in circular paths and immediately become quiescent, suggesting that Java carp sperm motility is activated in hypotonic aquatic environment without Ca2+. Goby sperm swam straightforward in the presence or absence of Ca2+. Percentages of motile sperm increased in 100-200 mOsm/kg but suppressed by removal of Ca2+. Regarding sperm motility and trajectory, no response was found in catfish sperm. These results suggest that a response to Ca2+ is different among sperm of the three species and suited to their habitat.     

The Composite Task Reveals Stronger Holistic Processing in Children than Adults for Child Faces

Background

While own-age faces have been reported to be better recognized than other-age faces, the underlying cause of this phenomenon remains unclear. One potential cause is holistic face processing, a special kind of perceptual and cognitive processing reserved for perceiving upright faces. Previous studies have indeed found that adults show stronger holistic processing when looking at adult faces compared to child faces, but whether a similar own-age bias exists in children remains to be shown.

Methodology/Principal Findings

Here we used the composite face task – a standard test of holistic face processing – to investigate if, for child faces, holistic processing is stronger for children than adults. Results showed child participants (8–13 years) had a larger composite effect than adult participants (22–65 years).

Conclusions/Significance

Our finding suggests that differences in strength of holistic processing may underlie the own-age bias on recognition memory. We discuss the origin of own-age biases in terms of relative experience, face-space tuning, and social categorization.     

Formation of a New Biogenic Aldehyde Adduct by Incubation of Tryptamine with Rat Brain Tissue

Tryptamine was degraded by incubation with rat brain homogenate to an unknown product. The reaction was stimulated by the nonionic detergents Triton X-100 and Lubrol PX and less by the zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]1-propanesulfonate (CHAPS). The same results were obtained with pig brain and bovine brain. The monoamine oxidase inhibitor pargyline inhibited the reaction strongly, indicating the participation of the enzyme on the reaction. Addition of 17,000 g supernatant from rat brain homogenate increased the formation effectively whereas phospholipids or chloroform/methanol (7:3) extract from the 17,000 g supernatant showed only little or no effect. Chromatographic and electrophoretic properties as well as the chemical reaction of the product with specific reagents suggest that the compound consists of an indole part and an amino acid part. The product could be identified by fast atom bombardment mass spectrometry and by comparison with the synthetic substance (4R)-2-(3-indolylmethyl)-1,3-thiazolidine-4-carboxylic acid. It is formed by the enzymatic oxidation of tryptamine producing indole-3-acetaldehyde which spontaneously cyclizes with free L-cysteine from the tissue. The results suggest that the reaction of biogenic aldehydes with brain macromolecules may proceed via an analogous reaction.     

Degradation of tryptamine in pig brain: identification of a new condensation product

Incubation of tryptamine with pig brain homogenate led to the formation of a product which is not identical with other known tryptamine metabolites. The same results were observed with rat brain tissue and bovine brain tissue. The compound has been isolated and identified by NMR spectroscopy, fast atom bombardment mass spectroscopy, and by chemical synthesis as a thiazolidine derivative, (4R)-2-(3-indolylmethyl)-1,3-thiazolidine-4-carboxylic acid. It is formed by a condensation reaction of indole-3-acetaldehyde generated enzymatically from tryptamine and of free L-cysteine present in the tissue. The compound inhibited monoamine oxidase (preferentially type A) and the neuronal gamma-aminobutyric acid uptake.     

Plant functional types and traits as biodiversity indicators for tropical forests: two biogeographically separated case studies including birds, mammals and termites

Multi-taxon surveys were conducted in species-rich, lowland palaeotropical and neotropical forested landscapes in Sumatra, Indonesia and Mato Grosso, Brazil. Gradient-directed transects (gradsects) were sampled across a range of forested land use mosaics, using a uniform protocol to simultaneously record vegetation (vascular plant species, plant functional types (PFTs) and vegetation structure), vertebrates (birds, mammals) and invertebrates (termites), in addition to measuring site and soil properties, including carbon stocks. At both sites similar correlations were detected between major components of structure (mean canopy height, woody basal area and litter depth) and the diversities of plant species and PFTs. A plant species to PFT ratio [spp.:PFTs] was the best overall predictor of animal diversity, especially termite species richness in Sumatra. To a notable extent vegetation structure also correlated with animal diversity. These surrogates demonstrate generic links between habitat structural elements, carbon stocks and biodiversity. They may also offer practical low-cost indicators for rapid assessment in tropical forest landscapes.     

Effects of logging rotation in a lowland dipterocarp forest on mating system and gene flow in <Emphasis Type="Italic">Shorea parvifolia</Emphasis>

Selective logging is one of several silvicultural practices used in sustainable forest management in the lowland dipterocarp forest in Indonesia. Selecting only trees with diameters >50 cm for logging can reduce the density of reproductive trees, thereby affecting pollen dispersal and influencing the mating system among remaining trees. We evaluated the effect of logging rotations on the mating system, gene flow and genetic diversity in populations of Shorea parvifolia in primary forest, and in first and second rotation forest. Our results revealed that multiple (or at least two) selective logging events with a 30-year logging rotation had a significant impact on the genetic diversity of pollen clouds. However, the average pollen dispersal distance did not differ significantly among the multiple selective logging rotations. The multiple rotations reduced the outcrossing rate and the number effective of pollen donors in the logged forest. Moreover, the number of pollen donors in a plot was affected by the basal area of reproductive trees present. These results suggest that reducing the number of reproductive trees by logging with multiple rotations might increase the bi-parental inbreeding rate due to the reduction in density of reproductive trees in a selectively logged forest. We conclude that multiple rotations with a 30-year cycle of selective logging as currently practiced would reduce the density of reproductive trees, and would not be sustainable in terms of maintaining genetic diversity in tropical forests of Southeast Asia.     

Land-use change and irrigation systems in the agricultural landscape of terraced paddy fields in Awaji Island, central Japan

We analyzed changes in land use from 1963 to 2000 in the northern part of Awaji Island in central Japan, using topographical maps and aerial photographs. We compared these changes between two different irrigation systems: tazu, in which a community group jointly owns the rights to a water source, and private management. The study area consisted of 57.3% paddy field, 22.2% woodland, 7.2% urban land use, 6.3% grassland, 5.8% water body, and 1.2% dry field in 1963. In 2000, the area consisted of 44.3% paddy field, 21.0% woodland, 12.6% urban land use, 11.6% grassland, 5.3% water body, and 5.0% dry field. The proportion of agricultural use had decreased markedly over the 37-year period. In the tazu area, 38.1 and 37.7% of former paddy field had changed into urban land use and grassland, respectively, and 19.3% of former paddy field had become dry field by 2000. In contrast, 30.6% of former rice paddy had become dry field in the private management area. About half of the former rice paddy had changed into grassland (26.3%) and urban land use (24.0%) in the private area, and 18.6% had become woodland in 2000. In the tazu area, there were fewer abandoned fields, because farmers still manage their fields according to strict regulations. In the private management area, the set-aside or abandoned fields had changed into woodlands as a result of vegetation succession, because farmers had abandoned fields located far from their homes or on steep slopes. These results suggest that the irrigation system may influence the pattern of change in land use.     

Landscape ecology and urban biodiversity in tropical Indonesian cities

Indonesia has recently been faced with a number of great problems: poverty, natural disasters such as tsunami, earthquakes, flooding and typhoons, volcanic eruptions, loss of biodiversity, decreasing water quality and quantity, increased pollution, and aesthetic degradation of the landscape. These disturbances have been caused by rapid changes in land use and land cover, deforestation, the application of monoculture farming systems in commercial agriculture, urbanization, industrialization, and other types of infrastructure development. The government, urban communities and companies have promoted some programs to ameliorate the problem of environmental degradation. The government has ratified law no. 26/2007 as a commitment to sustainability; this law ensures that cities are obliged to provide green open spaces covering a minimum of 30% of urbanized areas. Many metropolitan cities have feverishly enacted policies to promote greening programs, such as those applied in Jakarta. However, a new town—Sentul City—has engaged in policies that aim to create a well-designed eco-city with urban greenery and ecological networks. This new policy is supposed to herald a better future for urban quality. It is expected that green spaces will provide environmental services: water resource management, biodiversity conservation, carbon sequestration, and landscape beauty.     

Population status of a cryptic top predator: an island-wide assessment of tigers in Sumatran rainforests

Large carnivores living in tropical rainforests are under immense pressure from the rapid conversion of their habitat. In response, millions of dollars are spent on conserving these species. However, the cost-effectiveness of such investments is poorly understood and this is largely because the requisite population estimates are difficult to achieve at appropriate spatial scales for these secretive species. Here, we apply a robust detection/non-detection sampling technique to produce the first reliable population metric (occupancy) for a critically endangered large carnivore; the Sumatran tiger (Panthera tigris sumatrae). From 2007–2009, seven landscapes were surveyed through 13,511 km of transects in 394 grid cells (17×17 km). Tiger sign was detected in 206 cells, producing a naive estimate of 0.52. However, after controlling for an unequal detection probability (where p = 0.13±0.017; ±S.E.), the estimated tiger occupancy was 0.72±0.048. Whilst the Sumatra-wide survey results gives cause for optimism, a significant negative correlation between occupancy and recent deforestation was found. For example, the Northern Riau landscape had an average deforestation rate of 9.8%/yr and by far the lowest occupancy (0.33±0.055). Our results highlight the key tiger areas in need of protection and have led to one area (Leuser-Ulu Masen) being upgraded as a ‘global priority’ for wild tiger conservation. However, Sumatra has one of the highest global deforestation rates and the two largest tiger landscapes identified in this study will become highly fragmented if their respective proposed roads networks are approved. Thus, it is vital that the Indonesian government tackles these threats, e.g. through improved land-use planning, if it is to succeed in meeting its ambitious National Tiger Recovery Plan targets of doubling the number of Sumatran tigers by 2022.     

Perception and possible utilization of moonlight intensity for reproductive activities in a lunar-synchronized spawner, the golden rabbitfish

Rabbitfishes are known to spawn synchronously around the species-specific lunar phase. It is considered that they perceive and utilize cues from the moon in order to be synchronized gonadal development and spawning with the lunar cycle. Using the golden rabbitfish, Siganus guttatus, which spawns synchronously around the first quarter moon during the reproductive season, we measured the fluctuation of melatonin levels and examined the response of the fish to moonlight intensity. Daily fluctuation of melatonin concentration in the blood of golden rabbitfish showed low levels during daytime and high levels during night-time, suggesting that melatonin functions in the perception and utilization of photoperiod. Plasma melatonin concentration at the new moon was higher than that at the full moon. When the fish were exposed to moonlight at midnight of the both moon phases, the melatonin concentrations decreased to the control levels. These results show that the fish possibly perceive moonlight intensity and plasma melatonin fluctuates according to 'lightness' at a point of night. At the first spawning period (experiment was started one month before the spawning), the fish reared under natural conditions spawned at the expected spawning dates, whereas the fish reared under the constant darkness and lightness of night did not spawn. At the second spawning period (experiment was started 2 weeks before the spawning), the fish reared under the conditions of natural and constant darkness of night spawned but not that of constant lightness of night. It is possible that night conditions are related to synchronous gonadal development and spawning in the golden rabbitfish.