Ecological interactions affecting the role of mosquito larvae on dengue virus transmission.

In the course of their life cycle, mosquitoes undergo an ontogenetic niche shift; immature larval development occurs within an aquatic habitat from which adult mosquitoes subsequently disperse into the terrestrial environment. While adult female mosquitoes transmit dengue to humans, the larval stage influences dengue virus transmission significantly in several ways. The biotic and abiotic conditions in which larvae develop influence epidemiologically important aspects of adult life history and influence the geographic distribution of mosquito species. Through vertical transmission, mosquitoes may serve as reservoir hosts for dengue during periods that are unfavorable for transmission to humans. For my dissertation, I conducted research that investigated how environmental conditions experienced by larvae influence dengue transmission both directly and indirectly. In chapter 1, I experimentally infected Aedes aegypti and Aedes albopictus larvae to determine their susceptibility to dengue and evaluate the potential for horizontal transmission within the larval habitat. I found that larvae are susceptible to dengue and that horizontal transmission could be possible. In chapter 2, I tested the hypothesis that dengue infection affected mosquito fitness. The effect of infection was sex dependent; infected males took significantly longer to develop and were significantly smaller, while infection in females was cost-free. This result indicates that female larvae infected through vertical transmission are likely to be able to transmit dengue to humans as adults. In chapter 3 and 4, I investigated how resources within the larval habitat influence development and competition. Using larval detritus as a resource, I studied its utilization within the habitat, and its influence on larval development and competition. I found that larval detritus was consumed rapidly and differently from another type of invertebrate detritus. When larval detritus was the main resource within the larval habitat, Ae. albopictus significantly outcompeted Ae. aegypti; Ae. aegypti were significantly smaller and took longer to develop when reared in containers with Ae. albopictus. This result indicates that interspecific competition with Ae. albopictus significantly decreases the population growth of Ae. aegypti and may influence its ability to transmit dengue. Overall, my results further demonstrate the influential role of mosquito larvae on dengue transmission and epidemiology

A perfusion culture system for assessing bone marrow stromal cell differentiation on PLGA scaffolds for bone repair

Biomaterials development for bone repair is currently hindered by the lack of physiologically relevant in vitro testing systems. Here we describe the novel use of a bi-directional perfusion bioreactor to support the long term culture of human bone marrow stromal cells (BMSCs) differentiated on polylactic co-glycolic acid (PLGA). Primary human BMSCs were seeded onto porous PLGA scaffolds and cultured in static vs. perfusion culture conditions for 21 days in osteogenic vs. control media. PLGA scaffolds were osteoconductive, supporting a mature osteogenic phenotype as shown by the upregulation of Runx2 and the early osteocyte marker E11. Perfusion culture enhanced the expression of osteogenic genes Osteocalcin and Osteopontin. Extracellular matrix deposition and mineralisation were spatially regulated within PLGA scaffolds in a donor dependant manner. This, together with the observed upregulation of Collagen type X suggested an environment permissive for the study of differentiation pathways associated with both intramembranous and endochondral ossification routes of bone healing. This culture system offers a platform to assess BMSC behavior on candidate biomaterials under physiologically relevant conditions. Use of this system may improve our understanding of the environmental cues orchestrating BMSC differentiation and enable fine tuning of biomaterial design as we develop tissue-engineered strategies for bone regeneration

Analisis Aktivitas Dari Jamur Endofit Yang Terdapat Dalam Tumbuhan Bakau Avicennia Marina Di Tasik Ria Minahasa

Endofit dapat diartikan sebagai mikroba yang hidup berkoloni dalam jaringan internal tumbuhan tanpa menyebabkan efek yang merugikan secara langsung pada tumbuhan tersebut. Organisme endofitik memiliki potensi yang sangat besar untuk dieksploitasi dan menghasilkan produk alami baru yang bermanfaat di bidang kedokteran, pertanian, dan industri. Pada sisi yang lain kebutuhan terhadap obat-obatan baru yang membantu umat manusia melawan pelbagai penyakit tidak pernah berhenti, hal ini disebabkan adanya resistensi bakteri, infeksi virus, insidensi infeksi jamur, berbagai jenis tumor, infeksi parasit dan protozoa, di dalam populasi dunia sekarang ini sebagai akibat ketidakmampuan kita untuk mengatasi tidak hanya problematika kesehatan. Indonesia sebagai daerah tropis dengan keanekaragaman hayati yang cukup besar, di lain pihak, perlawanan endofit di ekosistem daerah tropis melawan organisme patogen dan predator cukup besar, sumber daya yang terbatas dan tekanan seleksi alam sangat tinggi. Hal ini menimbulkan kemungkinan besar bahwa endofit di daerah tropis seperti di negara kita merupakan sumber struktur senyawa baru dengan aktivitas biologis yang menarik untuk dikembangkan sebagai bahan obat baru. Penelitian ini merupakan penelitian untuk mencari kandidat obat-obatan baru yang difokuskan pada kandidat bahan obat yang memiliki potensi antibakteri dan antikanker. Tumbuhan bakau Avicennia marina diambil dari Pantai Tasik Ria. Jamur endofit diisolasi hingga diperoleh 2 isolat galur murni Aspergillus sp. dan Acremonium sp. Kedua isolat kemudian diuji aktivitasnya terhadap bakteri patogen Staphylococcus aureus dan Escherichia coli dengan menggunakan metode ko-kultivasi. Acremonium sp. memiliki aktivitas antibakteri yang lebih kuat dibandingkan dengan jamur Aspergillus sp. terhadap bakteri S. aureus, sedangkan Aspergillus sp. menunjukkan aktivitas antibakteri yang tinggi terhadap bakteri E. coli

Six years of study on fast growing forest plantations catchments in the Northwest of Spain

Data on water balance in three fast growing forest plantations experimental catchments in the northwest of Spain are presented. Two watersheds are covered by Eucalyptus globulus and other is covered by Pinus pinaster. During the six years of study severa1 perturbations occurred. In 1989 two consecutives wildfires affected to one E. globulus watershed. The second fire also bumed the other eucalyptus watershed. All eucalyptus were felled since 1991 to 1992. Also 25% of the watershed area in the pine catchment was cutted in 1991. Quick changes in the hydrologycal regimen took place after these perturbations. The very fast recovering capacity after fire and cutting of Eucalyptus globulus facilitated the retum to pre-fire hydrologic parameter values within only a few years. Before perturbations occurred, nutrient balances were very conservative, and were similar among the cathments. This indicates a good performance on the part of both tree plantations. Water comsumption for pine and eucalyptus stands was very similar

A Generalised Semantic Cognition Account of Aesthetic Experience

Given that aesthetic experiences typically involve extracting meaning from environment, we believe that semantic cognition research has much to offer the field of neuroaesthetics. In the current paper, we propose a generalised framework that is inspired by the semantic cognition literature and that treats aesthetic experience as just one example of how meaning accumulates. According to our framework, aesthetic experiences are underpinned by the same cognitive and brain systems that are involved in deriving meaning from the environment in general, such as modality-specific conceptual representations and controlled processes for retrieving the appropriate type of information. Our generalised semantic cognition view of aesthetic experience has substantial implications for theory development: it leads to novel, falsifiable predictions and it reconfigures foundational assumptions regarding the structure of the cognitive and brain systems that may be involved in aesthetic experiences.ISSN:1873-3514ISSN:0028-393

MUC5AC mucin release from human airways in vitro: effects of indomethacin and Bay X1005.

BACKGROUND: Increased secretion of mucus is a hallmark of many respiratory diseases and contributes significantly to the airflow limitation experienced by many patients. While the current pharmacological approach to reducing mucus and sputum production in patients is limited, clinical studies have suggested that drugs which inhibit the cyclooxygenase and/or 5-lipoxygenase enzymatic pathways may reduce secretory activity in patients with airway disease. AIM: This study was performed to investigate the effects of indomethacin (cyclooxygenase inhibitor) and Bay x 1005 (5-lipoxygenase inhibitor) on MUC5AC release from human airways in vitro. METHODS: An immunoradiometric assay was used to determine the quantities of MUC5AC present in the biological fluids derived from human airways in vitro. The measurements were made with a mixture of eight monoclonal antibodies (MAbs; PM8) of which the 21 M1 MAb recognized a recombinant M1 mucin partially encoded by the MUC5AC gene. RESULTS: The quantities of MUC5AC detected in the biological fluids derived from human bronchial preparations were not modified after treatment with indomethacin (cyclooxygenase inhibitor) and/or an inhibitor of the 5-lipoxygenase metabolic pathway (BAY x 1005). CONCLUSION: These results suggest that the cyclooxygenase and 5-lipoxygenase metabolic pathways play little or no role in the release of MUC5AC from human airways

The free d-aspartic acid and d-glutamic acid content of sheep milk and sheep milk products

The role of D-amino acids of foods in the human health is a strongly discussed topic and usually, data came from the investigation of cow milk. We have studied the free D-aspartic acid and free D-glutamic acid content of sheep milk, heat-treated sheep milk at various temperatures and various products of sheep milk. Raw sheep milk didn’t contain free D-aspartic and D-glutamic acid in remarkable amount and ratio 5.92% free D-aspartic acid; 2.62% free D-glutamic acid). Our heat-treatments didn’t cause major change in the free D-aspartic and D-glutamic acid content (max.: 7.8% free D-aspartic acid; 5.3% free D-glutamic acid in total free aspartic and glutamic acid). Contrary, all of the investigated products contained high level of free D-amino acids. The free D-aspartic acid and free D-glutamic acid content of the products were 16,9-39,5%,and 13,3-27% in the percent of total free amino acids. The racemization of aspartic acid was higher, than that of glutamic acid in every product. The D-amino acid content of fermented milk products was higher than in different cheeses