A Novel Antimicrobial Peptide, Dermaseptin-SS1, with Anti-Proliferative Activity, Isolated from the Skin Secretion of Phyllomedusa tarsius

The emergence of multidrug-resistant bacteria has severely increased the burden on the global health system, and such pathogenic infections are considered a great threat to human well-being. Antimicrobial peptides, due to their potent antimicrobial activity and low possibility of inducing resistance, are increasingly attracting great interest. Herein, a novel dermaseptin peptide, named Dermaseptin-SS1 (SS1), was identified from a skin-secretion-derived cDNA library of the South/Central American tarsier leaf frog, Phyllomedusa tarsius, using a 'shotgun' cloning strategy. The chemically synthesized peptide SS1 was found to be broadly effective against Gram-negative bacteria with low haemolytic activity in vitro. A designed synthetic analogue of SS1, named peptide 14V5K, showed lower salt sensitivity and more rapid bacteria killing compared to SS1. Both peptides employed a membrane-targeting mechanism to kill Escherichia coli. The antiproliferative activity of SS1 and its analogues against lung cancer cell lines was found to be significant.

Distribution and abundance of Peleng Tarsier (Tarsius pelengensis) in Banggai Island group, Indonesia

The Peleng tarsier (Tarsius pelengensis) is poorly known primate, with a range limited to Banggai island-group, Central Sulawesi, Indonesia. It was classified as "Endangered" by IUCN in 2017 based on extremely limited demographic and distributional data. The aim of this study was to collect and analyze data on the population and distribution of Peleng tarsiers. Surveys were conducted over approximately 5 months in 2017 and 2018 across Peleng and the neighboring islands of Banggai, Labobo, and Bangkurung. We determined that tarsiers only occur on Peleng and Banggai Island. The average population density in Peleng and Banggai was estimated to be 234 individuals/km2. This is comparable to the broad ranges of tarsier densities throughout Sulawesi and offshore islands. Peleng tarsiers were found in all elevations (0-937 m above sea level) and nearly all vegetated habitats in Peleng island. Using the IUCN criteria for determining conservation status, in conjunction with our new data, we believe that the Peleng tarsier population should be classified as "Vulnerable".

Accessing local knowledge to identify where species of conservation concern occur in a tropical forest landscape

Conventional biodiversity surveys play an important role in ensuring good conservation friendly management in tropical forest regions but are demanding in terms of expertise, time, and budget. Can local people help? Here, we illustrate how local knowledge can support low cost conservation surveys. We worked in the Malinau watershed, East Kalimantan, Indonesia, an area currently at risk of extensive forest loss. We selected eight species of regional conservation interest: rafflesia (Rafflesia spp.), black orchid (Coelogyne pandurata), sun bear (Helarctos malayanus), tarsier (Tarsius bancanus), slow loris (Nycticebus coucang), proboscis monkey (Nasalis larvatus), clouded leopard (Neofelis diardi/N. nebulosa), and orang-utan (Pongo pygmaeus). We asked 52 informants in seven villages if, where and when they had observed these species. We used maps, based on both geo-referenced and sketched features, to record these observations. Verification concerns and related issues are discussed. Evaluations suggest our local information is reliable. Our study took 6 weeks and cost about USD 5000. Extensive expert based field surveys across the same region would cost one or two orders of magnitude more. The records extend the known distribution for sun bear, tarsier, slow loris, and clouded leopard. Reports of rafflesia, proboscis monkey, and orang-utan are of immediate conservation significance. While quality concerns should never be abandoned, we conclude that local people can help expand our knowledge of large areas in an effective, reliable, and low cost manner and thus contribute to improved management.

Function of snake mobbing in spectral tarsiers

Numerous species are known for their tendency to approach and confront their predators as a group. This behavior is known as mobbing. Snakes seem to be one of the more consistent recipients of this type of predator-directed behavior. This paper explores individual differences (sex and age) in the mobbing behavior of the spectral tarsier toward live and model snakes. This study was conducted at Tangkoko Nature Reserve (Sulawesi, Indonesia) during 2003-2004. During this research, 11 natural mobbing events and 31 artificially induced mobbing events were observed. The mean number of individuals at a mobbing was 5.7. The duration of mobbing events was strongly correlated with the number of assembled mobbers. Adults were more likely than other age classes to participate in mobbings. Males were more likely than females to participate in mobbings. Mobbing groups often contained more than one adult male, despite the fact that no spectral tarsier group contains more than one adult male. No difference in body size between extragroup males and resident males was observed, refuting the "attract the mightier" hypothesis. The number of mobbers did not affect whether the tarsier or the snake retreated first, countering the "move-on" hypothesis. The "perception advertisement" hypothesis was tentatively supported, in that live snakes were rarely seen in the area following mobbing calls, in comparison to when tarsiers either ignored the snake or alarm call.

The mechanics of food reduction in Tarsius bancanus. Hard-object feeder, soft-object feeder or both?

The high-cusped, almost tritubercular teeth of Bornean tarsiers are used to reduce a wide variety of animal food. Prey is characteristically consumed entire, no parts being discarded. This paper attempts to identify the dental characteristics which permit tarsiers to reduce food substrates with widely varying mechanical properties and to assess whether reduction of some substrates incurs greater costs for tarsiers. Finite elements stress analysis (FESA) modelling is used to compare the effectiveness of tarsier and human teeth in reducing three types of food substrate habitually reduced by both species. Bone is taken as the exemplar of strong, stiff substrates, skin as the exemplar of substrates low in both stiffness and strength, and tendon as the exemplar of low-stiffness but strong substrates. The parameters used to measure performance are the work that must be done to bring tensile stresses to the point where tensile failure will be initiated and the bite-force required to do so. Human molars perform best in reducing bone, and tarsier molars in reducing skin. Neither perform as well in reducing tendon. Blunt, bunodont human molars perform slightly better than the high-cusped molars of tarsiers in reducing bone, but tarsier molars perform much better than human molars in inducing failure in skin and are also considerably better in reducing tendon. While the reduction effectiveness of human molars is greatly affected by substrate properties, the high cusps of tarsier teeth enable them to reduce foodstuffs of widely differing properties reasonably well. Scaling factors undoubtedly influence selection for cusp height, since high cusps are a prerequisite of effective crack propagation in food substrates by small animals. Microwear features do not show a consistent pattern where striations are associated with surface-parallel loads but pitting with surface-normal loads (at least as modelled by FESA). However, FESA modelling of the magnitude of applied forces and relative food/tooth displacement during occlusion suggest that the type of wear found in different regions is governed by the combined influences of relative tooth/food displacement and food/tooth reaction force. Pitting is associated with low levels of food/tooth displacement but high levels of reaction force, striation with high levels of displacement but low levels of force, and stripping or gouging of enamel with high values of both displacement and reaction force.

Unusual pattern of retinogeniculate projections in the controversial primate Tarsius

Studies of simian and prosimian primates have demonstrated a remarkable interspecific constancy in the pattern of innervation of the magnocellular and parvocellular layers of the dorsal lateral geniculate nucleus (dLGN) by retinal afferents. The characteristic organization of this nucleus in primates, as well as its apparent phylogenetic stability, have led to the proposal that the distinct laminar arrangement of the dLGN is one of the diagnostic characters that define the Order Primates. Here, we describe the distribution of retinal afferents to the dLGN of Tarsius, the single contemporary member of an ancient lineage of primates. In this genus, the more superficial layer of the dLGN receives projections from the ipsilateral eye, a unique situation among the members of the Order Primates. This observation adds support to the proposal that Tarsius does not share a more recent common ancestry with simians as compared with lemuriform and lorisiform primates.