Kajian Potensi Energi Arus Laut Sebagai Energi Alternatif Untuk Pembangkit Listrik Di Perarian Selat Lembeh, Sulawesi Utara

Kebutuhan akan energi listrik terus mengalami peningkatan dan sumber energi utamanya adalah energi konvensional yang ketersediannya terbatas di alam, untuk itu diperlukan adanya pencarian sumber energi lain yang terbarukan. Selat Lembeh merupakan wilayah perairan sempit yang berada di antara Laut Maluku yang dipengaruhi oleh massa air dari Pasifik dan Laut Sulawesi yang dipengaruhi oleh massa air dari Hindia. Penelitian ini bertujuan untuk mengetahui karakteristik arus laut serta mengetahui potensi arus laut sebagai sumber energi alternatif pembangkit listrik. Pengolahan data terdiri dari analisa data arus dan pasang surut, pemodelan numerik, dan menghitung estimasi rapat daya. Penelitian ini menggunakan metode kuantitatif dan penentuan lokasi dengan sampling area. Berdasarkan hasil penelitian, rapat daya terbesar yang dihasilkan yaitu pada musim barat, sebesar 120,02 kW/m2

Embryonic Origin of Olfactory Circuitry in <em>Drosophila</em>: Contact and Activity-Mediated Interactions Pattern Connectivity in the Antennal Lobe

<div><p>Olfactory neuropiles across different phyla organize into glomerular structures where afferents from a single olfactory receptor class synapse with uniglomerular projecting interneurons. In adult <em>Drosophila</em>, olfactory projection interneurons, partially instructed by the larval olfactory system laid down during embryogenesis, pattern the developing antennal lobe prior to the ingrowth of afferents. In vertebrates it is the afferents that initiate and regulate the development of the first olfactory neuropile. Here we investigate for the first time the embryonic assembly of the <em>Drosophila</em> olfactory network. We use dye injection and genetic labelling to show that during embryogenesis, afferent ingrowth pioneers the development of the olfactory lobe. With a combination of laser ablation experiments and electrophysiological recording from living embryos, we show that olfactory lobe development depends sequentially on contact-mediated and activity-dependent interactions and reveal an unpredicted degree of similarity between the olfactory system development of vertebrates and that of the <em>Drosophila</em> embryo. Our electrophysiological investigation is also the first systematic study of the onset and developmental maturation of normal patterns of spontaneous activity in olfactory sensory neurons, and we uncover some of the mechanisms regulating its dynamics. We find that as development proceeds, activity patterns change, in a way that favours information transfer, and that this change is in part driven by the expression of olfactory receptors. Our findings show an unexpected similarity between the early development of olfactory networks in <em>Drosophila</em> and vertebrates and demonstrate developmental mechanisms that can lead to an improved coding capacity in olfactory neurons.</p> </div

Recording from OSNs during development.

<p>(A–D) OSN recording technique. (A) Schematic showing the way in which the recordings were performed. Embryos were dissected to expose the DOG, a suction electrode was placed in contact with the DOG, and suction applied until a seal was made and action potentials were visible on the recording. (B) Example recording trace from a first instar larvae expressing ChR2 in OSNs (<i>Orco-Gal4;UAS-CD8GFP/UAS-ChR2</i>). The blue bar at the bottom indicates the period of time when the UV light was turned on to activate ChR2. In this particular recording three different units were identified using Spikepy. (C) Experimental trace from (B) showing the shape of individual spikes. (D) Clusters separated with Spikepy. Average spike shapes are plotted with their standard deviation at the top left. The other three panels are an overlay of a maximum of 250 individual spikes for each cluster, with the average spike shape plotted in black. (E) Peri-stimulus time histogram (PSTH), Raster plots, and heat maps showing the response to UV light stimulation of 16 units recorded in three different larvae in response to five different stimuli presentations in <i>Orco-Gal4;UAS-CD8GFP/UAS-ChR2</i> animals. PSTH (top panel) shows the average firing rate of the 16 units in 200 ms bins. Raster plots (middle panel) show the raw data for each of the 16 units. Heat maps (bottom panel) show for each unit the firing rate in 1 s bins. For each unit the average firing rate in the 10 s before light stimulation was significantly lower (<i>p</i><0.001) than the average firing rate in the 10 s during the stimulation. (F) Firing rate, example trace, and example spike shape of OSN recordings at four different developmental stages.</p

Developmental changes in OSN spontaneous activity patterns depend upon OR function.

<p>(A) Five-minute representative trace recordings overlaid with individual OSN units as identified with Spikepy. Top trace control 15 h AEL, middle trace control first instar larvae, and bottom trace Orco mutant first instar larva. OSNs at early stages (15 h and 16 h AEL) often fire in bursts, unlike OSNs at later stages (18.5 h and first instar larvae). OSNs in Orco mutants show throughout development and even in first instar larva stages bursty activity patterns. (B) Coefficient of variation of the interspike intervals (CV) at different developmental stages in controls (blue) and <i>Orco</i> mutants (red). CV is significantly higher in 16 h AEL embryos and first instar <i>Orco</i> mutants than in controls, which demonstrates that at least part of the reduction in spike train variability as development proceeds is due to OR expression. (C) Firing rate at different developmental stages in controls (blue) and <i>Orco</i> mutants (red). The firing rate at 16 h AEL is similar in <i>Orco</i> mutants and controls, but there is a significant difference between controls and <i>Orco</i> mutants in first instar larvae. (B–C) Error bars represent SEM. A single asterisk (*) indicates <i>p</i>≤0.05. <i>N.S.</i> indicates <i>p</i>>0.05.</p

PNs require presynaptic innervation during development for their survival.

<p>(A) Schematic of the experimental approach. OSNs on one side were laser ablated at stage 14, before OSN axons contact PNs. Animals were left to develop and hatch and PN morphology was examined in mid-first instar larvae. (B) Anterior part of a first instar larva in which OSNs have been unilaterally ablated. All sensory neurons are labelled using <i>PO163-Gal4;UAS-CD8GFP</i>, including taste neurons that appear as the most anteriorly located cluster of PO163 positive cells on both sides. OSNs labelled both with PO163 in green and with α-Orco antibody (magenta) are present on the control side (bottom) but not in the ablated side (top). (C) Quantification of the OSN ablation experiments. Number of PNs in the control (blue dots) and OSN ablated side (pink dots) for each animal are linked by a grey line. (D–D″) Z projection of a brain in which OSNs were unilaterally ablated (right side). PNs visible with <i>GH146-QF;QUAS-mTomato</i> on the control side are missing on the ablated side. The AL, visualized with Nc82 antibody staining in the control side (dashed line), is absent on the ablated side. (E–E″) Z projection of a brain in which OSNs were unilaterally ablated (right side). PNs (<i>GH146-QF;QUAS-mTomato</i>) can be seen innervating the AL in the control side. Some PN of the ablated side are missing, while surviving ones are found innervating the subesophageal ganglion (SOG). The AL, visualized in the control side as a gap with DAPI staining, is missing on the ablated side (see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001400#pbio.1001400.s002" target="_blank">Figure S2</a>).</p

Development of OSNs and PNs between 10 h and 14 h AEL.

<p>(A–F) OSN and PN development as followed with <i>acj6-Gal4:UAS-CD8GFP</i> between 10 h and 12 h AEL, before any contact is made. In the schematics (A–C, G, and K) OSNs are yellow and PNs green. The black square in the schematics indicates the region that is being visualized in the confocal images. In the confocal stacks (E–F, J, L, and M) OSN axons are indicated with an arrow and PN cell bodies with an asterisk. (A–B and D–E) OSNs are born in direct contact with the brain (dashed line) and send short axonal projections into the brain from the very early stages (arrow in E). (F) At early stage 15 (11.2–12 h AEL) OSNs and PNs have not yet contacted each other, although they are within filopodial reach. (G–J) OSN dye injections at 13 h AEL. (G) Schematic showing the injection procedure and marking the region shown in the confocal stacks (H–J) with a black square. (H) Injection of two OSNs with different dyes showing growth cones in both OSNs. (I) Schematic showing the position of OSN axons and PNs. Both components are in red, as in the confocal pictures, showing GFP staining expressed on the acj6-Gal4 pattern. One OSN is green showing filopodia, which represents a single injected OSN as in (J and J′). OSN axons enter the brain in a ventral position respective to PN cell bodies. PN axons run ventrally towards the place of OSN terminals and then turn dorsally towards higher brain centres, making thus a U shape. Different PNs turn their axons at different dorso-ventral depths, and OSN axonal growth cones contact even the most dorsally turning PN axons. The line in (I) marked with the letter J′ represents the confocal z stack shown in (J′). (J) is a confocal z projection of what is represented in (I), while (J′) is a single z stack at the position indicated in (I). From here onwards letters with apostrophe (‘) indicate images taken from the same animal. (K–M) PN dye injections at 14 h AEL. (K) Schematic showing the injection procedure and marking the regions (AL, and MB&LH) shown in the confocal stacks (L–M). (L–M) In each example a single PN was injected (green), and all OSNs and PNs are labelled in red with <i>acj6-Gal4;UAS-CD8GFP</i>. The AL and the MB and LH regions are shown for each injected PN. At 14 h AEL PNs have already extended axons towards higher brain centres, but they have not yet sprouted dendrites at the AL. The axons in the MB and LH are still immature with growth cones. Arrows indicate OSN axons, and brackets indicate the region where the AL is forming and therefore the region where PNs will sprout dendrites.</p

Development of OSNs and PNs between 16 h and 21 h AEL.

<p>(A–I) Development of OSNs between 16 h and 21 h AEL as revealed by dye injection. (A) Schematic of the injection procedure; as in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001400#pbio-1001400-g001" target="_blank">Figure 1</a>, the square indicates the area shown in the confocal images. Columns show injections at different developmental times. The two rows (B–E) and (F–I) each represent a different example of OSN injection. All figures are at the same scale. Terminals at 21 h AEL (E and I) appear more compact than at earlier stages. Morphologies found at 18.5 h AEL (two examples in D and H) are especially variable, with some showing long filopodia (H) or broad regions of occupancy (D). (J–N′) Development of PNs between 16 h and 21 h AEL as revealed by dye injection. (J) as (A). (K–N′) The two rows show the AL and the MB and LH regions for a representative PN injection at each developmental stage. Red brackets indicate the PN dendrites.</p

CSDn modulates odour-guided behaviour.

<p>The pair of CSDn is specifically labeled by <i>R60FO2</i>Gal4. Targeted expression of GFP using <i>R60FO2</i>Gal4 (<i>R60F02</i>Gal4/+; UAS <i>mCD8GFP</i>/+) shows a pair of neurons with anatomy characteristic of the CSDn and (Ai–Aii) innervations to the antennal lobe (Brp in red; GFP in green). (Aiii–vi) The neurons labeled by <i>R60F02</i> co-express 5-HT (red) indicating it is indeed the CSDn (green; Brp in blue). Asterisks indicate cell body of the CSDn. (B–F) The CSDn modulates olfactory response of adult <i>Drosophila</i> towards CO₂. (B) Suppression of evoked synaptic transmission by targeted expression of tetanus toxin light chain (TNTG) in the CSDn (<i>R60F02</i>Gal4/+; UAS <i>TNTG</i>/+, n = 10, p = 0.017) leads to an increase in CO₂ avoidance index compared to control animals (<i>R60F02</i>Gal4/+; UAS <i>TNTVIF</i>/+, n = 12). (C) Similar increase in CO₂ sensitivity is observed upon suppression of CSDn excitability by targeted K_ir2.1 expression (<i>R60F02</i>Gal4/+; UAS <i>K_ir2.1</i>/+, n = 11, p<0.01 compared to controls) in the CSDn. (D) CSDn function is required in the adults for modulating olfactory behaviour. Adult-specific expression of K_ir2.1 in the CSDn is achieved by rearing animals (<i>R60F02</i>Gal4/+; UAS <i>K_ir2.1</i>/+; Tub-<i>Gal80^ts</i>/+) at 18°C throughout development (white bars in D) and then shifting to 29°C after eclosion (black bars in D). Adult-specific suppression of CSDn excitability results in increased CO₂ avoidance (n = 17; p = 0.006). (E) In a reporter line for serotonin receptor 5-HT_1BDro (<i>5-HT_1BDro</i>-Gal4/+; UAS-<i>2xEGFP</i>/+), a group of local interneurons are labeled (red arrows) along with mushroom bodies (yellow arrowheads). (F) RNAi-mediated knock down of 5-HT_1BDro in the 5-HT_1BDro expression domain (<i>5-HT_1BDro</i>-Gal4/+; UAS-<i>5-HT_1BDroRNAi</i>/+, n = 11) results in increased CO₂ sensitivity (p<0.05 compared to all control genotypes, n>7). 5-HT_1BDro expression outside the mushroom bodies, likely in the AL, may be necessary for CO₂ sensitivity as blocking <i>5-HT_1BDroRNAi</i> expression in mushroom body neurons (MB-Gal80/+; <i>5-HT_1BDro</i>-Gal4/+; UAS-<i>5-HT_1BDroRNAi</i>/+, n = 14) does not ameliorate increased CO₂ sensitivity (p = 0.12 compared to <i>5-HT_1BDro</i>-Gal4/+; UAS-<i>5-HT_1BDroRNAi</i>/+, n = 11) and animals exhibit increased CO₂ avoidance (p<0.01 compared to all control genotypes, n>7). Significance was assessed by <i>Mann-Whitney</i> test. *, p<0.05; **, p<0.01; ***, p<0.0001; n.s. (not significant), p>0.05.</p

Perturbation in Levels of Eph signaling leads to defective glomeruli-specific positioning of the terminal of the CSDn.

<p>(A-A″, H) Innervation pattern of the axonal terminals of the CSDn (green) in glomeruli VA1l/m, VA1d and DA1 (anti-Brp in red) in control adults is shown (n≥6). (B-B″, H) In <i>Eph</i> null animals, axonal terminals of the CSDn show overall reduction in their AL innervation. This defect is pronounced in glomeruli which normally receive more innervations from the CSDn (VA1d (n = 4, p<0.001), VA1l/m (n = 4, p = 0.127), DA1 (n = 4, p = 0.025), DL3 (n = 4, p = 0.745) and V (n = 4, p<0.001). (C-C″, I) Targeted expression of Eph in the CSDn results in exquisite reversal of the terminal arborization pattern in these glomeruli compared to controls; terminals preferentially target VA1l/m (n = 5, p = 0.002), DA1 (n = 5, p<0.001), DL3 (n = 5, p = 0.003) and avoid glomerulus VA1d (n = 5, p<0.001). (H–I) Quantification of total axonal branch tip number is plotted in a histogram. Asterisks indicate glomeruli with fewer innervations and arrowhead indicates glomerulus with more innervations from the CSDn. A one-way repeated measure ANOVA test was performed to assess significant difference between the genotypes (F = 27.341, P<0.001). All pairwise multiple comparisions were performed using Fisher LSD method. *, p<0.05; **, p<0.01; ***, p<0.0001; n.s. (not significant), p>0.05. Scale bar = 20 µm. (D–G) Glomeruli-specific innervation of axonal terminals is achieved by directed growth of axonal terminals of the CSDn. Terminal arbors of the CSDn in (D–E) control (RN2<i>flp</i>, <i>tub</i>>CD2>Gal4, UAS<i>mCD8GFP</i>/+) and (F–G) <i>Eph</i> mutant animals (RN2<i>flp</i>, <i>tub</i>>CD2>Gal4, UAS<i>mCD8GFP</i>/+; <i>Eph^X652</i>). Developmental profile of the axonal terminals of control CSDn at (D) 50 hAPF and (E) 70 hAPF is shown. (D) At 50 hAPF, very few axonal terminals of the CSDn can be seen extending to region of the AL where VA1l/m, VA1d, DA1 and DL3 are located. (E) Adult-like pattern of glomeruli-specific innervation of axonal terminals is apparent at 70 hAPF where high innervation of VA1d and low innervation of VA1l/m and DA1 by the CSDn terminals is seen. (F) At 50 hAPF, axonal terminals of the CSDn in <i>Eph</i> null mutants can be seen near the region of AL where the above-mentioned four glomeruli are located but (G) fail to innervate these glomeruli even at 70 hAPF. Asterisks indicate glomeruli with fewer innervations and arrowhead indicates glomerulus with more innervations from the CSDn. Scale bar = 20 µm.</p

Glomerular-specific innervation pattern of the CSDn in the AL is regulated by Ephrin.

<p>(A-A″, E) Innervation pattern of the axonal terminals of the CSDn (green) in glomeruli VA1l/m, VA1d and DA1 (anti-Brp in red) in control adults is shown (n>6). Asterisks indicate glomeruli with fewer innervations and arrowhead indicates glomerulus with more innervations from the CSDn. (B-B″, F) In <i>Ephrin^KG09118</i> hypomorphs, increased terminal innervations can be seen to VA1l/m (n = 5, p<0.001), DA1 (n = 5, p<0.001) and DL3 (n = 9, p = 0.018) while innervations in VA1d (n = 5, p = 0.865) and V (n = 4, p = 0.149) are comparable to controls. (D-D″, G) Targeted expression of Ephrin in the CSDn in <i>Ephrin^KG09118</i> hypomorphs restores distribution of axonal terminals in VA1l/m (n = 6, p = 0.99), glomerulus DA1 (n = 6, p = 0.606) and glomerulus DL3 (n = 6, p = 0.992). (C-C″, G) Targeted expression of Ephrin in the CSDn does not change overall distribution pattern of axonal tips in VA1l/m (n = 8, p = 0.241), DA1 (n = 8, p = 0.092233) and DL3 (n = 8, p = 0.910) when compared to controls, however a small decrease in overall branch tip number is observed. (E–G) Quantification of total axonal branch tip number in glomeruli V, VA1l/m, VA1d, DA1 and DL3 is plotted in histograms. A one-way repeated measure ANOVA test was performed to assess significant difference between the genotypes (F = 28.544, P<0.001). All pairwise multiple comparisions were performed using Fisher LSD method.. *, p<0.05; **, p<0.01; ***, p<0.0001; n.s. (not significant), p>0.05. (H–L) Ephrin shows broad expression pattern and it is expressed throughout the developing AL (n>5). APF = After puparium formation. All the images hereafter are oriented as indicated in A′ unless otherwise mentioned. D, dorsal; M, medial. Scale bar = 20 µm. See also <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003452#pgen.1003452.s005" target="_blank">Table S1</a>.</p