Tropical forest dung beetle-mammal dung interaction networks remain similar across an environmental disturbance gradient.

Conservation outcomes could be greatly enhanced if strategies addressing anthropogenic land-use change considered the impacts of these changes on entire communities as well as on individual species. Examining how species interactions change across gradients of habitat disturbance allows us to predict the cascading consequences of species extinctions and the response of ecological networks to environmental change. We conducted the first detailed study of changes in a commensalist network of mammals and dung beetles across an environmental disturbance gradient, from primary tropical forest to plantations, which varied in above-ground carbon density (ACD) and mammal communities. Mammal diversity changed only slightly across the gradient, remaining high even in oil palm plantations and fragmented forest. Dung beetle species richness, however, declined in response to lower ACD and was particularly low in plantations and the most disturbed forest sites. Three of the five network metrics (nestedness, network specialization and functionality) were significantly affected by changes in dung beetle species richness and ACD, but mammal diversity was not an important predictor of network structure. Overall, the interaction networks remained structurally and functionally similar across the gradient, only becoming simplified (i.e. with fewer dung beetle species and fewer interactions) in the most disturbed sites. We suggest that the high diversity of mammals, even in disturbed forests, combined with the generalist feeding patterns of dung beetles, confer resilience to the commensalist dung beetle-mammal networks. This study highlights the importance of protecting logged and fragmented forests to maintain interaction networks and potentially prevent extinction cascades in human-modified systems.

Key Roles of Dipterocarpaceae, Bark Type Diversity and Tree Size in Lowland Rainforests of Northeast Borneo-Using Functional Traits of Lichens to Distinguish Plots of Old Growth and Regenerating Logged Forests.

Many lowland rainforests in Southeast Asia are severely altered by selective logging and there is a need for rapid assessment methods to identify characteristic communities of old growth forests and to monitor restoration success in regenerating forests. We have studied the effect of logging on the diversity and composition of lichen communities on trunks of trees in lowland rainforests of northeast Borneo dominated by Dipterocarpaceae. Using data from field observations and vouchers collected from plots in disturbed and undisturbed forests, we compared a taxonomy-based and a taxon-free method. Vouchers were identified to genus or genus group and assigned to functional groups based on sets of functional traits. Both datasets allowed the detection of significant differences in lichen communities between disturbed and undisturbed forest plots. Bark type diversity and the proportion of large trees, particularly those belonging to the family Dipterocarpaceae, were the main drivers of lichen community structure. Our results confirm the usefulness of a functional groups approach for the rapid assessment of tropical lowland rainforests in Southeast Asia. A high proportion of Dipterocarpaceae trees is revealed as an essential element for the restoration of near natural lichen communities in lowland rainforests of Southeast Asia.

Antiparasitic Potential of Chromatographic Fractions of Nephrolepis biserrata and Liquid Chromatography-Quadrupole Time-of-Flight-Mass Spectrometry Analysis.

Marine aquaculture development is recently impeded by parasitic leech Zeylanicobdella arugamensis (Hirudinea, Piscicolidae) in Sabah, Malaysia. The parasitic leech infests a variety of cultured fishes in aquaculture facilities. In this study, we evaluated the antiparasitic activity of the chromatographic fractions of the medicinal plant Nephrolepis biserrata methanol extract against Z. arugamensis and highlighted the potential metabolites responsible for the antiparasitic properties through liquid chromatography (LC)-quadrupole time-of-flight (QTOF)-mass spectrometry (MS) analysis. Out of seven fractions obtained through flash column chromatography techniques, three fractions demonstrated antiparasitic properties. Significant parasitic mortality was indicated by fraction 3 at a concentration of 2.50 mg/mL, all the leeches were killed in a time limit of 1.92 ± 0.59 min. followed by fraction 4 (14 mg/mL) in 34.57 ± 3.39 and fraction 5 (15.3 mg/mL) in 36.82 ± 4.53 min. LC-QTOF-MS analysis indicated the presence of secondary metabolites including phytosphingosine (6), pyrethrosin (1), haplophytine (9), ivalin (2), warburganal (3), isodomedin (4) and pheophorbide a (16), representing sphingoid, alkaloid, terpenoid, phenolic and flavonoid groups. Thus, our study indicated that the chromatographic fractions of N. biserrata demonstrated significant antiparasitic activity against the marine parasitic leeches due to the presence of potent antiparasitic bioactive compounds.

Bioactivities of Lyngbyabellins from Cyanobacteria of Moorea and Okeania Genera.

Cyanobacteria are reported as rich sources of secondary metabolites that provide biological activities such as enzyme inhibition and cytotoxicity. Ten depsipeptide derivatives (lyngbyabellins) were isolated from a Malaysian Moorea bouillonii and a Red Sea Okeania sp.: lyngbyabellins G (1), O (2), P (3), H (4), A (7), 27-deoxylyngbyabellin A (5), and homohydroxydolabellin (6). This study indicated that lyngbyabellins displayed cytotoxicity, antimalarial, and antifouling activities. The isolated compounds were tested for cytotoxic effect against human breast cancer cells (MCF7), for antifouling activity against Amphibalanus amphitrite barnacle larvae, and for antiplasmodial effect towards Plasmodium falciparum. Lyngbyabellins A and G displayed potent antiplasmodial effect against Plasmodium, whereas homohydroxydolabellin showed moderate effect. For antifouling activity, the side chain decreases the activity slightly, but the essential feature is the acyclic structure. As previously reported, the acyclic lyngbyabellins are less cytotoxic than the corresponding cyclic ones, and the side chain increases cytotoxicity. This study revealed that lyngbyabellins, despite being cytotoxic agents as previously reported, also exhibit antimalarial and antifouling activities. The unique chemical structures and functionalities of lyngbyabellin play an essential role in their biological activities.

Biosurfactants from Marine Cyanobacteria Collected in Sabah, Malaysia.

Chemical investigation of the organic extract from Moorea bouillonii, collected in Sabah, Malaysia, led to the isolation of three new chlorinated fatty acid amides, columbamides F (1), G (2), and H (3). The planar structures of 1-3 were established by a combination of mass spectrometric and NMR spectroscopic analyses. The absolute configuration of 1 was determined by Marfey's analysis of its hydrolysate and chiral-phase HPLC analysis after conversion and esterification with Ohrui's acid, (1S,2S)-2-(anthracene-2,3-dicarboximido)cyclohexanecarboxylic acid. Compound 1 showed biosurfactant activity by an oil displacement assay. Related known fatty acid amides columbamide D and serinolamide C exhibited biosurfactant activity with critical micelle concentrations of about 0.34 and 0.78 mM, respectively.

Twenty-six new species of Hoploscopa (Lepidoptera, Crambidae) from South-East Asia revealed by morphology and DNA barcoding.

Hoploscopa Meyrick (Lepidoptera: Crambidae) is a fern-feeding genus found in montane areas of South-East Asia and Melanesia, eastwards up to the Samoan Islands. It includes sixteen described species, with at least 70 further undescribed species known from scientific collections. An iterative approach including morphological and molecular characters was used in order to explore the diversity of Hoploscopa. The hitherto described species are revised, and descriptions authored by T. Léger and M. Nuss are provided for an additional 26 new species: H. agtuuganonensis sp. nov., H. albipuncta sp. nov., H. albomaculata sp. nov., H. anacantha sp. nov., H. boleta sp. nov., H. cynodonta sp. nov., H. danaoensis sp. nov., H. gombongi sp. nov., H. gracilis sp. nov., H. ignitamaculae sp. nov., H. isarogensis sp. nov., H. jubata sp. nov., H. kelama sp. nov., H. kinabaluensis sp. nov., H. mallyi sp. nov., H. marijoweissae sp. nov., H. matheae sp. nov., H. niveofascia sp. nov., H. pangrangoensis sp. nov., H. parvimacula sp. nov., H. pseudometacrossa sp. nov., H. sepanggi sp. nov., H. sumatrensis sp. nov., H. titika sp. nov., H. tonsepi sp. nov., H. ypsilon sp. nov. Using a protocol specific for the amplification of DNA from old museum specimens, we recovered 101 COI barcodes for all but one of the newly described species, with 76 being barcode compliant (>487 bp). Species delimitation analyses suggest cryptic diversity, with six cases reflecting allopatric divergence, and two further cases found in sympatry.

A New Epi-neoverrucosane-type Diterpenoid from the Liverwort Pleurozia subinflata in Borneo.

New bioactive 13-epi-neoverrucosane diterpenoid, 5ß-acetoxy-13-epi-neoverrucosanic acid (1) along with three known secondary metabolites, 13-epi-neoverrucosan-5ß-ol (2), chelodane (3) and (E)-ß-farnesene (4) were isolated from the MeOH extract of east Malaysia's liverwort Pleurozia subinflata. The chemical structure of new compound was elucidated by the analyses of its spectroscopic data (FTIR, NMR and HR-ESI-MS). These epi-neoverrucosane-type compounds seem to be notable chemosystematic markers for P. subinflata in Borneo. Compound 3 was widespread in marine sponges however this is the first record for 3 to be found in liverwort. These metabolites were tested for their antifungal potentials against selected fungi from the marine environment. Compound 1 exhibited effective antifungal activity against Lagenidium thermophilum.

Two new epimers of C15-acetogenin, 4-epi-isolaurallene and 4-epi-itomanallene A as diastereomeric model.

Two new C15-acetogenins, 4-epi-isolaurallene (1) and 4-epi-itomanallene A (2) were isolated from a population of marine red alga Laurencia nangii Masuda from Carrington Reef. The structures of these compounds were determined intensively by NMR and HRESIMS data. Their configurations were elucidated by detailed comparison of chemical shifts, germinal protons splitting and NOE correlations with known and synthesized analogues. In addition, antibacterial activities of these compounds were evaluated. These compounds would serve as diastereomeric models for future reference. Since the isolaurallene, neolaurallene, 9-acetoxy-1,10,12-tribromo-4,7:6,13-bisepoxypentadeca-1,2-diene, itomanallene A and laurendecumallene A were isolated, compounds 1 and 2 were the sixth example of C15-acetogenin with dioxabicyclo[7.3.0]dodecene skeleton.

A regional study of the genus Phyllopsora (Ramalinaceae) in Asia and Melanesia.

Phyllopsora is a crustose to squamulose lichen genus inhabiting the bark of trees in moist tropical forests and rainforests. Species identification is generally challenging and is mainly based on ascospore morphology, thallus morphology and anatomy, vegetative dispersal units, and on secondary chemistry. While regional treatments of the genus have been conducted for Africa, South America and Australia, there exists no study focusing on the Asian and Melanesian species. Previously, 24 species of Phyllopsora s. str. have been reported from major national studies and checklists representing 13 countries. We have studied herbarium material of 625 Phyllopsora specimens from 18 countries using morphology, anatomy, secondary chemistry, and molecular data to investigate the diversity of Phyllopsora species in Asia and Melanesia. We report the occurrence of 28 species of Phyllopsora including the following three species described as new to science: P.sabahana from Malaysia, P.siamensis from Thailand and P.pseudocorallina from Asia and Africa. Eight species are reported as new to Asia. A key to the Asian and Melanesian species of Phyllopsora is provided.

Nangallenes A and B, halogenated nonterpenoid C15-acetogenins from the Bornean red alga Laurencia nangii.

Two new halogenated nonterpenoids C15-acetogenins, nangallenes A-B (1-2), together with two known halogenated compounds itomanallene A (3) and 2,10-dibromo-3-chloro-α-chamigrene (4), were isolated and identified from the organic extract of the marine red alga Laurencia nangii Masuda collected from the coastal waters in Semporna, Borneo. Their structures were established by means of spectroscopic analysis including IR, high-resolution electrospray ionization mass spectrometry (HRESI-MS), and 1D and 2D NMR techniques. All these metabolites were submitted for the antifungal assay against four species of selected marine fungi. Compounds 1-4 showed potent activity against Haliphthoros sabahensis and Lagenidium thermophilum.

Three new species of Krogia (Ramalinaceae, lichenised Ascomycota) from the Paleotropics.

Krogiaborneensis Kistenich & Timdal, K.isidiata Kistenich & Timdal and K.macrophylla Kistenich & Timdal are described as new species, the first from Borneo and the two latter from New Caledonia. The new species are supported by morphology, secondary chemistry and DNA sequence data. Krogiaborneensis and K.isidiata contain sekikaic and homosekikaic acid, both compounds reported here for the first time from the genus. Krogiamacrophylla contains an unknown compound apparently related to boninic acid as the major compound. DNA sequences (mtSSU and nrITS) are provided for the first time for Krogia and a phylogeny of the genus based on 15 accessions of five of the six accepted species is presented. Krogiaantillarum is reported as new to Brazil, Guatemala and Mexico.

Global dung webs: high trophic generalism of dung beetles along the latitudinal diversity gradient.

At the global scale, species diversity is known to strongly increase towards the equator for most taxa. According to theory, a higher resource specificity of consumers facilitates the coexistence of a larger number of species and has been suggested as an explanation for the latitudinal diversity gradient. However, only few studies support the predicted increase in specialisation or even showed opposite results. Surprisingly, analyses for detritivores are still missing. Therefore, we performed an analysis on the degree of trophic specialisation of dung beetles. We summarised 45 studies, covering the resource preferences of a total of 994503 individuals, to calculate the dung specificity in each study region. Our results highlighted a significant (4.3-fold) increase in the diversity of beetles attracted to vertebrate dung towards the equator. However, their resource specificity was low, unrelated to diversity and revealed a highly generalistic use of dung resources that remained similar along the latitudinal gradient.

Bioactive Cembranoids from the Soft Coral Genus Sinularia sp. in Borneo.

Soft corals are known to be prolific producers of a wide spectrum of biologically active cembranoids. One new cembranoid, sinularolide F (2), along with three known compounds, cembranolide (1), (E,E,E)-6,10,14-trimethyl-3-methylene-cis-3α,4,5,8,9,12,13,15α-octahydrocyclo tetradeca[ß]furan-2(3H)-one (3), and denticulatolide (4), were isolated from the Bornean soft coral Sinularia sp. Compounds 2 and 4 showed potential anti-inflammatory activities against lipopolysaccharide-stimulated RAW 264.7 with IC50 values less than 6.25 µg/mL and anticancer activity against HL60 cell lines. The compounds' mechanisms of action were investigated via the Western blot evaluation of their protein markers. These activities could be attributed to the presence of tertiary methyl at C-8 and the compounds' 3D configurations.

Logging disturbance shifts net primary productivity and its allocation in Bornean tropical forests.

Tropical forests play a major role in the carbon cycle of the terrestrial biosphere. Recent field studies have provided detailed descriptions of the carbon cycle of mature tropical forests, but logged or secondary forests have received much less attention. Here, we report the first measures of total net primary productivity (NPP) and its allocation along a disturbance gradient from old-growth forests to moderately and heavily logged forests in Malaysian Borneo. We measured the main NPP components (woody, fine root and canopy NPP) in old-growth (n = 6) and logged (n = 5) 1 ha forest plots. Overall, the total NPP did not differ between old-growth and logged forest (13.5 ± 0.5 and 15.7 ± 1.5 Mg C ha-1  year-1 respectively). However, logged forests allocated significantly higher fraction into woody NPP at the expense of the canopy NPP (42% and 48% into woody and canopy NPP, respectively, in old-growth forest vs 66% and 23% in logged forest). When controlling for local stand structure, NPP in logged forest stands was 41% higher, and woody NPP was 150% higher than in old-growth stands with similar basal area, but this was offset by structure effects (higher gap frequency and absence of large trees in logged forest). This pattern was not driven by species turnover: the average woody NPP of all species groups within logged forest (pioneers, nonpioneers, species unique to logged plots and species shared with old-growth plots) was similar. Hence, below a threshold of very heavy disturbance, logged forests can exhibit higher NPP and higher allocation to wood; such shifts in carbon cycling persist for decades after the logging event. Given that the majority of tropical forest biome has experienced some degree of logging, our results demonstrate that logging can cause substantial shifts in carbon production and allocation in tropical forests.

Impact of Land-use Change on Vertical Soil Bacterial Communities in Sabah.

Decline in forest productivity due to forest conversion is defining the Bornean landscape. Responses of bacterial communities due to land-use changes are vital and could define our understanding of ecosystem functions. This study reports the changes in bacterial community structure in organic soil (0-5 cm; O-Horizon) and organic-mineral soil (5-15 cm; A-Horizon) across Maliau Basin Conservation Area old growth forest (MBOG), Fragment E logged forest (FELF) located in Kalabakan Forest Reserve to Benta Wawasan oil palm plantation (BWOP) using two-step PCR amplicon analysis of bacteria DNA on Illumina Miseq next generation sequencing. A total of 30 soil samples yielded 893,752-OTU reads at ≥97% similarity from 5,446,512 good quality sequences. Soil from BWOP plantation showed highest unshared OTUs for organic (49.2%) and organic-mineral (50.9%) soil. MBOG soil showed a drop in unshared OTUs between organic (48.6%) and organic-mineral (33.9%). At phylum level, Proteobacteria dominated MBOG but shifted to Actinobacteria in logged and plantation soil. Present findings also indicated that only FELF exhibited change in bacterial communities along the soil depth, moving from the organic to the organic-mineral layer. Both layers of BWOP plantation soils deviated from other forests' soil in ß-diversity analysis. To our knowledge, this is the first report on transitions of bacterial community structures with different soil horizons in the tropical rainforest including Borneo, Sabah. Borneo tropical soils form a large reservoir for soil bacteria and future exploration is needed for fully understanding the diversity structure and their bacterial functional properties.

Columbamides D and E: Chlorinated Fatty Acid Amides from the Marine Cyanobacterium Moorea bouillonii Collected in Malaysia.

Two new chlorinated fatty acid amides, columbamides D (1) and E (2), along with apratoxins A and C and wewakazole, were isolated from the organic extract of a Moorea bouillonii sample from Sabah, Malaysia. Structure elucidation was accomplished by a combination of MS and NMR analyses. The total synthesis of all four stereoisomers of 1 was completed, and the absolute configuration was determined by chiral-phase HPLC and Marfey's analysis.

New Marine Antifouling Compounds from the Red Alga Laurencia sp.

Six new compounds, omaezol, intricatriol, hachijojimallenes A and B, debromoaplysinal, and 11,12-dihydro-3-hydroxyretinol have been isolated from four collections of Laurencia sp. These structures were determined by MS and NMR analyses. Their antifouling activities were evaluated together with eight previously known compounds isolated from the same samples. In particular, omaezol and hachijojimallene A showed potent activities (EC50 = 0.15-0.23 µg/mL) against larvae of the barnacle Amphibalanus amphitrite.

Three new cembranoids from the Bornean soft coral Nephthea sp.

Three new cembranoid diterpenes, 10-hydroxy-nephthenol acetate (1), 7,8-epoxy-10-hydroxy-nephthenol acetate (2), and 6-acetoxy-7,8-epoxy-10-hydroxy-nephthenol acetate (3), along with a known compound, 6-acetoxy-7,8-epoxy-nephthenol acetate (4), were isolated from the Bornean soft coral Nephthea sp. Antibacterial and anticancer activities were exhibited by compounds 1 and 2 against Staphylococcus aureus (ATCC 6538)/Escherichia coli (ATCC 13311) and Hela/MCF-7, respectively.

A new cembrane-type diterpenoid from Bornean liverwort Chandonanthus hirtellus.

A new compound, chandonanol (1), along with four known compounds, chandonanthone (2), iso-chandonanthone (3), anastreptene (4), and (6R,7S)-sesquiphellandrene (5), was isolated from the MeOH extract of Bornean liverwort Chandonanthus hirtellus. The structure of the new metabolite was established by analyses of the spectroscopic data (1D NMR, 2D NMR, HRESIMS, and IR). These compounds were tested for their activity against antibiotic-resistant clinical strains. Chandonanol (1) exhibited potent bactericidal activity against Staphylococcus aureus and Escherichia coli.

A New Seco-Clerodane-Type Diterpenoid from Bornean Liverwort Schistochila acuminata.

A new compound, schistochilic acid D (1) and two known compounds (2 and 3) were isolated from MeOH extract of Bornean liverwort. Schistochila acuininata collected from Mount Trus Madi, Sabah. The structure of the new metabolite was established based on spectroscopic (ID NMR, 2D NMR, and IR). and HRESIMS data. In addition, another population of S. acuminata collected from Mount Alab (Sabah) yielded four known compounds, 2, 3, 4 and 5. These compounds were tested for their biological potential against the B 16-Fl0 cell line. Compounds 4 and 5 exhibited weak cytotoxic activity.