FORAGING DISTANCE IN THE STINGLESS BEE Trigona thoracica

The foraging patterns of stingless bees are dependent on resource availability.Human alterations to natural areas will affect the condition of local habitats,and influence the bees' foraging behavior. In this study, we assessed thefamiliarity of Trigona thoracica with two distinct habitats. This studyinvestigates the familiarity of the stingless bee Trigona thoracica with twodistinct habitats. It has the dual purpose of comparing foraging distancebetween the intact forest and disturbed environments, and of evaluating theidea that bees create memory patterns for navigational purposes en route todestinations. We hypothesized that bees forage more frequently in thenatural environment than in the disturbed environment, and are thereforemore familiar with forested terrain. We also suspect that bees are able toform a visual memory in transport, and that they will integrate cues theyacquire in transition to guide themselves home from unfamiliar locations. Weselected a (medium-sized) colony of Trigona thoracica at the base of a Ficusmicrocarpa tree near the entrance to the Khao Chong Peninsular BotanicGardens. The nest was located in a relatively open area, adjacent to twodistinct environments: a densely wooded forest to the east and an altered,semi-natural environment along a highway to the west. One transect line wasplaced in each of these two areas, and three release points along the transectswere determined using GPS (East - Forest area: 350, 650, 1200m; West -Highway: 400, 800, 1200m).Outgoing bees were collected in plastic bags and tagged with paint markers,Collections ranging in size from sixteen to seventy bees were thentransported in an insect cage to designated release points either on foot or onmotorbike. At each location, two samples (covered and uncovered) werereleased at staggered times. The two transects were completed over thecourse of three days, with a total of twelve releases. On each day we hadsimilar sunny and dry weather conditions. On each day, the nest wasobserved from the first release to at least 1.25 hours after the last release; theactivity of marked bees (entering or exiting the hive) was recorded, as well asthe time of that activity. Percentage returns were calculated for each batch ofmarked bees released from each of the three releasing points on each transect,according to the recorded number of returns for each batch.There was no significant difference between the number of covered anduncovered bees that returned. This leads us to believe that the bees do notform memory when they are artificially transported, which may be due tofactors, which differ between artificial transport and normal flight behavior.Possible factors include the rate of movement, and the height of travel.Additionally, the mesh-and-plastic carrying cage may have skewed the bee'sexposure to sunlight and added an abnormal level of stress for the bee,altering the bee's ability to assess the solar pattern. These factors wouldcontribute to the bee's incapacity to use egocentric methods for homewardnavigation. We found that the bees are more familiar with the natural habitatthan the disturbed habitat. The forage distance was determined to be 3.676km in the forested area and 1.973 km along the highway

Assessment of tsunami damage on the .coastal vegetation in five selected districts in the coastal zone of Sri Lanka, after one and half years of tsunami

Tsunami, the ki lIer wave swept nearly two thirds of the coast of Sri Lanka on 26lh of December, 2004.About 40,000 people died and around 500,000 people were displaced, more than 119,000 housesdamaged either fully or partially. About 13 coastal districts were directly affected, the north and eastsuffered the brunt of the blow accounting for about 2/3 of deaths and 60% of displacements. In termsof ecological aspects, with the exception of few species, most of the vegetation suffered total orpartial death, lagoons, estuaries, coral reefs, sea grass beds, salt marshes and mangroves experiencedthe damage at varying levels. Th is study was conducted with the patronage of the Food and AgriculturalOrganisation of the UN to scientifically assess the response of the coastal ecosystems with specialreference to coastal forests to the Tsunami, almost one and half years of the incident.The study focused on 5 tsunami affected districts namely, Kalutara, Galle, Matara, Hambantota andArnpara. In each district, approximately 6 sampling locations selected based on the topography mapsand ground information. In each sampling location, a transect which was 10m wide and upto 250minland was taken. The transect was divided into 50m blocks, the first one laid at the start of vegetationline of the beach. In each 50m section of the transect, all the plant species were enumerated. For theground vegetation, percentage ground cover was taken. Using an index, the level of damage wasevaluated for each plant. Composite soil samples were taken at each 50m segment and analysed forElectrical Conductivity, Soil Organic Carbon and major nutrients. Water samples were taken fromexisting wells located close by.Although most of the vegetation, except for few exceptions, suffered badly at the time of Tsunami,there was extensive regeneration on the coast at the time of our study. The species which sufferedthe tsunami damage most were Palmyrah palm (Borassus flab ellifer), Del (Artocarplls nobilis),Araliya tBorassus flabellifer), Puwak (Areca catechu), Banana (Musa sppv; Kitul (Caryota urens),Guava (Psidium guajava), Avacardo pears (Persea gratissimai, trees of Citrus family ie Oranges,Lemon, Lime (Citrus spp.) Alstonia, Teak (Tectona grandis) etc. Of these, most of the species hadregenerated to varying degrees, the most difficult ones being Araliya, Palmyrah, plants of citrus family,Kitul, Guava.With a view to find out the species which are more robust in the regeneration, percentage groundcover (in ground vegetation) and relative abundance (in tree/shrub vegetation) were taken in each 50m segment of a plot. The districts did not vary significantly in the biodiversity. However, the speciesabundance showed a significant variation especially between the districts ofthe western coast (Kalutara,Galle, Matara) with that of south and eastern coasts (Hambantota and Ampara). While Mudu bimthamburu (Ipomea pescaprae) was the most prominent ground cover in the western districts, Maharavana ravul (Spinifex spp.) was more prominent in both south and eastern districts. With regard tothe abundance of trees/shrubs, Wetakeiyya (Pandanus spi, Coconuts (Cocos nuciferai, Gam suriya(Thespesia spp.y, Mudilla (Barringtonia spp.i, Domba were most abundant. In the South and Easterndistricts, Maliththan (Woodfordiafruitocosa), Andara (Prosopisjuliflora), Palmyrah palm, Cashwnut (Anacardium occidentale) and Neem iAzadirachta indica), Indi, (Phoenix spp) Korakaha/Kayan (Memecylon angustifoliumi were prominent. In the South and South-eastern districts, Aththana(Datura mete/), Wal kochchi had spread into invasive levels while the regeneration of Ranawara(Cassia auriculata) also had increased.With regard to the physical parameters, soil carbon content showed a decrease with the increase indistance from the beach. The Electrical Conductivity (EC) also showed a decreasing trend with theincreasing distance from the beach in all the districts studied. In general, all the nutrients (Total N,Available P, Available K, Ca, Mg and Na) showed an increase upto about 50m compared to that ofnon tsunami levels and then decreased. The pH of the water samples taken in all the districts werebetween 7-8 indicating a neutral level while the EC values were higher than the standard of 4 milsemens.With regard to the establishment of Green Belt, the coastal area could be broadly categorised intonatural, rural and urban landscapes. For the natural landscapes like mangroves, sand dunes and coastalforests, facilitation/restoration of the natural vegetation is recommended. Selection of species shouldbe in line with the naturally occurring ones in the ecosystem. In total locations, planting a strip ofnatural littoral woodland and strand plants seaward of agricultural crops is suitable. For urban locations,patches of natural vegetation could be integrated as far as possible with the most suitable concept forthe area. There could be open grassed/sandy/paved parks or playgrounds or sports grounds of varioussizes, provided there is a substantial belt of trees on the seaward side, and in cyclone prone areas,wind shelter belts on all sides. In cyclone prone areas, wind shelter belts should be planted aroundcrops and settlements: the trees and shrubs used could be introduced species as well as indigenous/native (found naturally in Sri Lanka) and endemic (found naturally only in Sri Lanka) species.The design of the Green belt should inc lude both ground vegetation, shrubs and then trees. Based onthe study results, composition of the vegetation for both ground vegetation, shrub layer and the treelayer has been proposed for all the 5 districts. In the tree layer, there were two distinctions, one for thebioshield which is located at close proximity to the sea and then the trees outside the bioshield comprisingof more multipurpose ones serving both protection and production purposes. Further, general designswere recommended for the west coast and southeast and eastern coasts. Guidelines were also proposedfor rehabilitation of the mangrove areas and sand dunes.

An assessment of vegetation and canopy structure of moderately exploited natural forest area in Yagirala forest reserve

Study assessed the vegetation composition and structure and the forest canopy structure in terms ofLeaf Area Index (LAI), Mean Leaf Angle (MLA) and canopy openness in different elevationalclasses of moderately exploited natural forest area which covers about 82% of total natural forestcover in Yagirala forest reserve, a tropical lowland rain forest selectively logged by State TimberCooperation in late 70's.Canopy architecture termed as angle distribution of foliage elements (Chen et al. 1992), can bequantified by the leaf area index (LAI) and mean leaf angle (MLA). In this study Hemisphericalphotographic method was used to characterize canopy architecture at three elevational classes (i.e.valley, mid-slope and ridge top). At each elevational class, hemispherical photos ofthe forest canopywere taken at each sampling point at a height of l m above the ground along transects up to 200m at50m intervals. Hemispherical photographs were analyzed using Hemiview 2.1 canopy analysis softwareA vegetation survey was carried out to determine floristic composition of dam inant species and fam i!ies,which contribute more to the forest canopy. The enumeration was carried out using 0.05 ha circularplots at three elevational classes, totally covering 0.6ha of the area. Individuals taller 1m were enumeratedand species, diameter at breast height (dbh) and total height measurements were recorded and relativebasal area, relative frequency, relative density and Importance Value Index (IVI), diameter classdistribution were estimated.Leaf area index (LAI) and mean leaf angle (MLA) did not show significant variation between threeelevational classes. LAlmean value of low elevation areas show high value of2.256 and mean valueof high elevation areas show low value of 2.087. Average MLA value for the moderately exploitedarea is 29.14. Canopy openness given in terms of visual sky fraction is also not significantly diferentbetween three elevational classes. The results give an estimation of homogeneity of canopy opennesswithin the moderately exproited natural forest.

Resource efficient cleaner production (RECP) as a potential tool for greening the hospitality industry in Sri Lanka

Environmental pollution, changing patterns of consumption and production and increased sustainable development concerns create new challenges for companies worldwide. The hospitality sector activities are also strongly linked to the three pillars of sustainable development: economic competitiveness, social importance and environmental impact. Integrated and new approaches for materials and energy management are required to follow sustainable economic and ecological objectives and to succeed in the global. The concept of cleaner production suit the ideal business environment to tackle the challenges of the changing global context and offers concrete solutions for increases efficiency and reduces risks to humans and the environment.The hotel sector is a very important sector in current Sri Lankan economy. However it was identified that the industry is one of the highest consumers of energy and natural resources. According to the Sustainable Energy Authority the total hotel  load is estimated to be about 4-5 % of the total demand of the national grid. The average energy cost of a typical hotel is around 25% of its total operational cost.Comprehensive assessments were conducted in selected hotels according to the UNIDO CleanerProduction (CP) methodology. The study showed that the significant environmental issues in the context of daily hotel operations includeWater consumption and wastewater generation, Solid waste management and Air quality (indoors and outdoors). Also through an energy audit it was found that the key energy consuming areas of hotels include lighting, air conditioning, cooking etc. Air conditioning accounts for 50% of total energy consumption in a hotel.There are various practical CP options for hotel sector to reduce its impact on the environment and achieve cost savings which is important for industry performance in a competitive business environment. This study helped to identify CP options that can be implemented in hotel sector in general. Most of the CP options identified can be implemented with relatively short payback period. The findings of the case studies showed that on average about 25% of the water consumption, 20% waste generation and 20 % electricity consumption can be reduce in the five hotels studies.Keywords: Sustainable tourism, Green Hotel, Cleaner Production, Industrial Ecolog

Recombinant Dengue Type 2 Viruses with Altered E Protein Domain III Epitopes Are Efficiently Neutralized by Human Immune Sera

Humans develop polyclonal, serotype-specific neutralizing antibody responses after dengue virus (DENV) infection. Many mouse antibodies that neutralize DENV bind to the lateral ridge or A strand epitopes on domain III of the viral envelope (EDIII) protein. It has been assumed that these epitopes are also the main target of human neutralizing antibodies. Using recombinant dengue serotype 2 viruses with altered EDIII epitopes, we demonstrate that EDIII epitopes are not the main target of human neutralizing antibody

Identification of human neutralizing antibodies that bind to complex epitopes on dengue virions

Dengue is a mosquito-borne flavivirus that is spreading at an unprecedented rate and has developed into a major health and economic burden in over 50 countries. Even though infected individuals develop potent and long-lasting serotype-specific neutralizing antibodies (Abs), the epitopes engaged by human neutralizing Abs have not been identified. Here, we demonstrate that the dengue virus (DENV)-specific serum Ab response in humans consists of a large fraction of cross-reactive, poorly neutralizing Abs and a small fraction of serotype-specific, potently inhibitory Abs. Although many mouse-generated, strongly neutralizing monoclonal antibodies (mAbs) recognize epitopes that are present on recombinant DENV envelope (E) proteins, unexpectedly, the majority of neutralizing Abs in human immune sera bound to intact virions but not to the ectodomain of purified soluble E proteins. These conclusions with polyclonal Abs were confirmed with newly generated human mAbs derived from DENV-immune individuals. Two of three strongly neutralizing human mAbs bound to E protein epitopes that were preserved on the virion but not on recombinant E (rE) protein. We propose that humans produce Abs that neutralize DENV infection by binding a complex, quaternary structure epitope that is expressed only when E proteins are assembled on a virus particle. Mapping studies indicate that this epitope has a footprint that spans adjacent E protein dimers and includes residues at the hinge between domains I and II of E protein. These results have significant implications for the DENV Ab and vaccine field

In-Depth Analysis of the Antibody Response of Individuals Exposed to Primary Dengue Virus Infection

Humans who experience a primary dengue virus (DENV) infection develop antibodies that preferentially neutralize the homologous serotype responsible for infection. Affected individuals also generate cross-reactive antibodies against heterologous DENV serotypes, which are non-neutralizing. Dengue cross-reactive, non-neutralizing antibodies can enhance infection of Fc receptor bearing cells and, potentially, exacerbate disease. The actual binding sites of human antibody on the DENV particle are not well defined. We characterized the specificity and neutralization potency of polyclonal serum antibodies and memory B-cell derived monoclonal antibodies (hMAbs) from 2 individuals exposed to primary DENV infections. Most DENV-specific hMAbs were serotype cross-reactive and weakly neutralizing. Moreover, many hMAbs bound to the viral pre-membrane protein and other sites on the virus that were not preserved when the viral envelope protein was produced as a soluble, recombinant antigen (rE protein). Nonetheless, by modifying the screening procedure to detect rare antibodies that bound to rE, we were able to isolate and map human antibodies that strongly neutralized the homologous serotype of DENV. Our MAbs results indicate that, in these two individuals exposed to primary DENV infections, a small fraction of the total antibody response was responsible for virus neutralization

Dengue virus neutralizing antibody levels associated with protection from infection in Thai cluster studies

BACKGROUND: Long-term homologous and temporary heterologous protection from dengue virus (DENV) infection may be mediated by neutralizing antibodies. However, neutralizing antibody titers (NTs) have not been clearly associated with protection from infection. METHODOLOGY/PRINCIPAL FINDINGS: Data from two geographic cluster studies conducted in Kamphaeng Phet, Thailand were used for this analysis. In the first study (2004-2007), cluster investigations of 100-meter radius were triggered by DENV-infected index cases from a concurrent prospective cohort. Subjects between 6 months and 15 years old were evaluated for DENV infection at days 0 and 15 by DENV PCR and IgM ELISA. In the second study (2009-2012), clusters of 200-meter radius were triggered by DENV-infected index cases admitted to the provincial hospital. Subjects of any age 6 months and older were evaluated for DENV infection at days 0 and 14. In both studies, subjects who were DENV PCR positive at day 14/15 were considered to have been susceptible on day 0. Comparison subjects from houses in which someone had documented DENV infection, but the subject remained DENV negative at days 0 and 14/15, were considered non-susceptible. Day 0 samples were presumed to be from just before virus exposure, and underwent plaque reduction neutralization testing (PRNT). Seventeen susceptible (six DENV-1, five DENV-2, and six DENV-4), and 32 non-susceptible (13 exposed to DENV-1, 10 DENV-2, and 9 DENV-4) subjects were evaluated. Comparing subjects exposed to the same serotype, receiver operating characteristic (ROC) curves identified homotypic PRNT titers of 11, 323 and 16 for DENV-1, -2 and -4, respectively, to differentiate susceptible from non-susceptible subjects. CONCLUSIONS/SIGNIFICANCE: PRNT titers were associated with protection from infection by DENV-1, -2 and -4. Protective NTs appeared to be serotype-dependent and may be higher for DENV-2 than other serotypes. These findings are relevant for both dengue epidemiology studies and vaccine development efforts

A highly potent human antibody neutralizes dengue virus serotype 3 by binding across three surface proteins

Dengue virus (DENV) infects ~400 million people annually. There is no licensed vaccine or therapeutic drug. Only a small fraction of the total DENV-specific antibodies in a naturally occurring dengue infection consists of highly neutralizing antibodies. Here we show that the DENV-specific human monoclonal antibody 5J7 is exceptionally potent, neutralizing 50% of virus at nanogram-range antibody concentration. The 9 Å resolution cryo-electron microscopy structure of the Fab 5J7–DENV complex shows that a single Fab molecule binds across three envelope proteins and engages three functionally important domains, each from a different envelope protein. These domains are critical for receptor binding and fusion to the endosomal membrane. The ability to bind to multiple domains allows the antibody to fully coat the virus surface with only 60 copies of Fab, that is, half the amount compared with other potent antibodies. Our study reveals a highly efficient and unusual mechanism of molecular recognition by an antibody. There is no licensed vaccine or therapeutic for dengue virus (DENV) infection. Here, the authors show that a highly potent human monoclonal antibody binds to DENV particles in an unusual and very effective way by interacting with three viral envelope proteins

Analysis of Epitopes on Dengue Virus Envelope Protein Recognized by Monoclonal Antibodies and Polyclonal Human Sera by a High Throughput Assay

Dengue virus is the leading cause of arboviral diseases worldwide. The envelope protein is the major target of neutralizing antibodies and vaccine development. While previous studies have reported several epitopes on envelope protein, the possibility of interdomain epitopes and the relationship of epitopes to neutralizing potency remain unexplored. We developed a high throughput dot blot assay by using 67 alanine mutants of surface-exposed envelope residues as a systematic approach to identify epitopes recognized by mouse monoclonal antibodies and polyclonal human sera. Our results suggested the presence of interdomain epitopes more frequent than previously appreciated. Compared with monoclonal antibodies generated by traditional protocol, the potent neutralizing monoclonal antibodies generated by a new protocol showed several unique features of their epitopes. Moreover, the predominant epitopes of antibodies against envelope protein in polyclonal sera can be identified by this assay. These findings have implications for future development of epitope-specific diagnostics and epitope-based dengue vaccine, and add to our understanding of humoral immune responses to dengue virus at the epitope level