Qualitative and quantitative analyses of the composition and dynamics of light harvesting complex I in eukaryotic photosynthesis

The photosynthetic apparatus of eukaryotic organisms posseses a remarkable ability to adapt to ever changing light conditions and other environmental cues. In the present study, the compositon of plant light harvesting complex I (LHCI), its association with photosystem I (PSI) and its dynamic changes upon iron deficiency as one environmental variable were investigated by means of qualitative and quantitative proteome analyses using Chlamydomonas reinhardtii and Lycopersicon esculentum as model organisms. With stable isotope labelling and mass spectrometry, C. reinhardtii LHCI was shown to be heterogeneously composed with a total number of between six and eight proteins. In a study comparing the photosynthetic apparatus under iron sufficient and iron deficient conditions, N-terminal processing of Lhca3 was shown to be a key event in the remodelling of PSI-LHCI into a dissipative conformation upon iron deficiency. The results show that the heterogeneity and plasicity of LHCI enable the photosynthetic apparatus to function optimally under varying environmental conditions

Improving the Supply Chain of Tilapia Industry of the Philippines.pdf

This study evaluated the Philippine tilapia supply chain including the roles of key actors, logistical issues, external influences, and transaction flows among market levels. It identified improvement areas and provided recommendations for the industry. Key players include hatcheries, nurseries, commercial/small-scale farmers, consumers and institutional buyers. Pampanga, Batangas and Laguna are major tilapia sources while Metro Manila, Angeles and Baguio are the major demand centers. Dagupan is the major tilapia transshipment point for Northern Luzon. Many farmers employ a 'circuitous' production technique to meet markets' preferences. Direct buying and selling at central markets are the common operations of the tilapia industry. Consumers generally prefer whole live fish with size from 250-300 grams per fish. The requirements of institutional buyers are more varied. Filleted tilapia requires about 2-3 pieces per kg. High costs of logistics and transactions; lack of cold storage and transport vehicles; and meeting delivery requirements are the major concerns of nurseries, farmers and traders. Irregular supply of desired quality and volume of tilapia, limited capital for expansion, and predatory market practices are the main concerns of processors. Some recommendations to address the issues and concerns, are: encourage the establishment of more nurseries while intensifying technology transfer to farmers; conduct promotions for niche opportunities of tilapia; motivate small farmers to link with supply chains through an incentive mix; institutionalize an accreditation program for feed manufacturers, hatcheries, processors, etc.; and provide capital windows to improve facilities and reduce logistics and transaction costs in the entire supply chain

Improving the Supply Chain of Tilapia Industry of the Philippines

This study evaluated the Philippine tilapia supply chain including the roles of key actors, logistical issues, external influences, and transaction flows among market levels. It identified improvement areas and provided recommendations for the industry. Key players include hatcheries, nurseries, commercial/small-scale farmers, consumers and institutional buyers. Pampanga, Batangas and Laguna are major tilapia sources while Metro Manila, Angeles and Baguio are the major demand centers. Dagupan is the major tilapia transshipment point for Northern Luzon. Many farmers employ a 'circuitous' production technique to meet markets' preferences. Direct buying and selling at central markets are the common operations of the tilapia industry. Consumers generally prefer whole live fish with size from 250-300 grams per fish. The requirements of institutional buyers are more varied. Filleted tilapia requires about 2-3 pieces per kg. High costs of logistics and transactions; lack of cold storage and transport vehicles; and meeting delivery requirements are the major concerns of nurseries, farmers and traders. Irregular supply of desired quality and volume of tilapia, limited capital for expansion, and predatory market practices are the main concerns of processors. Some recommendations to address the issues and concerns, are: encourage the establishment of more nurseries while intensifying technology transfer to farmers; conduct promotions for niche opportunities of tilapia; motivate small farmers to link with supply chains through an incentive mix; institutionalize an accreditation program for feed manufacturers, hatcheries, processors, etc.; and provide capital windows to improve facilities and reduce logistics and transaction costs in the entire supply chain.This is part of the IIFET Special Session on Markets and Value Chains for Small Aquaculture & Fisheries Enterprises with a Focus on Gender that took place on 17 July 2012 in Dar Es Salaam, Tanzania in conjunction with 16th IIFET Conference. The complete proceedings of this special session are available ( http://aquafishcrsp.oregonstate.edu/Documents/Uploads/FileManager/IIFET%202012%20CRSP%20Session%20Proceedings%20Final_small.pdf) through the Aquaculture & Fisheries Collaborative Research Support Program gender web site, ( http://aquafishcrsp.oregonstate.edu/Gender/)

Plio-Pleistocene sea level and temperature fluctuations in the northwestern Pacific promoted speciation in the globally-distributed flathead mullet Mugil cephalus

<p>Abstract</p> <p>Background</p> <p>The study of speciation in the marine realm is challenging because of the apparent absence of physical barriers to dispersal, which are one of the main drivers of genetic diversity. Although phylogeographic studies using mitochondrial DNA (mtDNA) information often reveal significant genetic heterogeneity within marine species, the evolutionary significance of such diversity is difficult to interpret with these markers. In the northwestern (NW) Pacific, several studies have emphasised the potential importance of sea-level regression during the most recent glaciations as a driver of genetic diversity in marine species. These studies have failed, however, to determine whether the period of isolation was long enough for divergence to attain speciation. Among these marine species, the cosmopolitan estuarine-dependent fish <it>Mugil cephalus </it>represents an interesting case study. Several divergent allopatric mtDNA lineages have been described in this species worldwide, and three occur in sympatry in the NW Pacific.</p> <p>Results</p> <p>Ten nuclear microsatellites were surveyed to estimate the level of genetic isolation of these lineages and determine the role of sea-level fluctuation in the evolution of NW Pacific <it>M. cephalus</it>. Three cryptic species of <it>M. cephalus </it>were identified within this region (NWP1, 2 and 3) using an assignment test on the microsatellite data. Each species corresponds with one of the three mtDNA lineages in the COI phylogenetic tree. NWP3 is the most divergent species, with a distribution range that suggests tropical affinities, while NWP1, with a northward distribution from Taiwan to Russia, is a temperate species. NWP2 is distributed along the warm Kuroshio Current. The divergence of NWP1 from NWP2 dates back to the Pleistocene epoch and probably corresponds to the separation of the Japan and China Seas when sea levels dropped. Despite their subsequent range expansion since this period of glaciation, no gene flow was observed among these three lineages, indicating that speciation has been achieved.</p> <p>Conclusions</p> <p>This study successfully identified three cryptic species in <it>M. cephalus </it>inhabiting the NW Pacific, using a combination of microsatellites and mitochondrial genetic markers. The current genetic architecture of the <it>M. cephalus </it>species complex in the NW Pacific is the result of a complex interaction of contemporary processes and historical events. Sea level and temperature fluctuations during Plio-Pleistocene epochs probably played a major role in creating the marine species diversity of the NW Pacific that is found today.</p

Selfish drive can trump function when animal mitochondrial genomes compete.

Mitochondrial genomes compete for transmission from mother to progeny. We explored this competition by introducing a second genome into Drosophila melanogaster to follow transmission. Competitions between closely related genomes favored those functional in electron transport, resulting in a host-beneficial purifying selection. In contrast, matchups between distantly related genomes often favored those with negligible, negative or lethal consequences, indicating selfish selection. Exhibiting powerful selfish selection, a genome carrying a detrimental mutation displaced a complementing genome, leading to population death after several generations. In a different pairing, opposing selfish and purifying selection counterbalanced to give stable transmission of two genomes. Sequencing of recombinant mitochondrial genomes showed that the noncoding region, containing origins of replication, governs selfish transmission. Uniparental inheritance prevents encounters between distantly related genomes. Nonetheless, in each maternal lineage, constant competition among sibling genomes selects for super-replicators. We suggest that this relentless competition drives positive selection, promoting change in the sequences influencing transmission

Is the geographic variation in size of American eel Anguilla rostrata elvers due to genetic differentiation?

Elvers of the American eel Anguilla rostrata collected along the east coasts of North America and Haiti exhibited geographic variations in age and size at time of arrival at estuaries and in duration of glass eels as well as their growth rate, based on a previous otolith study. They were able to divide into two groups: the northern large size group and the southern small size group. Thus, this study aims to understand whether the geographic variation in size of elvers is due to genetic differentiation by using microsatellite DNA. A total of 216 elvers of A.rostrata, collected from 6 estuaries along the Atlantic coasts of Central and North America,were used for the microsatellite DNA (6 loci) analysis. The genetic analyses indicated that there were no geographical isolation in genetic structures between the northern and southern groups (FCT = -0.00101; P = 0.507), although there was a weak significant difference among sampling locations (FST = 0.00538; P < 0.05). The differences were patchy and did not correspond to the geographic difference in size of elvers. Integrating the preious otolith daily growth increment (ring) analyses and genetic data suggested that the geographic variation in size of the elver at estuarine arrival between these two groups was not due to genetic differentiation but to the distance of the estuaries from the spawning ground and latitudinal difference in coastal water temperatures

Satellite rainfall validation and assimilation into a weather forecast model

Rainfall is an integral part of the Philippines\u27 climate. Many of its sectors rely heavily on adequate amounts of precipitation to function. However, recent events have also highlighted how excessive rainfall also affects severely the Philippines. Extrem