Evaluation of fish handling techniques employed by artisanal fishers on quality of Lethrinids and Siganids fish genera at landing time along the Kenyan coast using sensory and microbiological methods

In artisanal fishery, traditional handling methods such as tossing fish onto the boat bottom or into woven mat baskets and gunny bags after capture are commonly employed. These practices accelerate fish spoilage due to cross contamination and exposure to high ambient temperature. This study aimed at investigating the effect of non-icing (onboard handling methods) on the quality of Lethrinids (Emperor fish, local name: Changu) and Siganids (Rabbitfish, local name: Tafi) landed along the Kenyan coast in comparison to iced fish. Monthly, samples were assessed by sensory methods using Quality Index Method (QIM), Total Viable Counts (TVC) and hydrogen sulphide (H2S) producing bacteria considered as specific spoilage organisms (SSO) counts for raw fish; Quantitative Descriptive Analysis (QDA) and Torry score for cooked fillets. Iced fish was characterised by better freshness quality attributes at landing time compared to non-iced at both landing sites. According to the QIM, iced treatment recorded better quality scores that were significantly different from non-iced groups (p<0.05) throughout the study with regard to fish genera. Cooked fillets showed both treatments to be within human consumption limits although non-iced fish were characterised by marginal quality attributes. Microbial assessment depicted TVC to be on average 102- 103 CFU/g and 103- 104 CFU/g in iced and non-iced Lethrinids respectively at both sampling sites. In Siganids higher numbers of 104- 105 CFU/g were recorded in non–iced group, with H2S producing bacteria constituting a higher proportion of TVC. Iced Siganids recorded 102- 103 CFU/g throughout the study. Fish quality was reported to be inconsistent over the sampled month which reflects the large pressure systems of the Western Indian Ocean and the two distinct monsoon periods considered to differ in warmth. The major cause of deteriorated fish quality observed at landing time in the fishery was attributed to bacterial proliferation accelerated most importantly by non-icing onboard handling practises reported such as tossing fish onto the boat bottom or into woven mat baskets and gunny bags employed by the fishers. Sensory evaluation of cooked fillets and microbiological analysis showed fish was acceptable for human consumption regardless of handling method employed. This assures consumers of acceptable fish quality at landing time as long as good hygienic practices are observed at subsequent stages to consumption.Key words: Lethrinids, Siganids, Quality, Sensory, Handlin

The ZmRCP-1 promoter of maize provides root tip specific expression of transgenes in plantain

Background Bananas and plantains (Musa spp.) provide 25 % of the food energy requirements for more than 100 million people in Africa. Plant parasitic nematodes cause severe losses to the crop due to lack of control options. The sterile nature of Musa spp. hampers conventional breeding but makes the crop suitable for genetic engineering. A constitutively expressed synthetic peptide in transgenic plantain has provided resistance against nematodes. Previous work with the peptide in potato plants indicates that targeting expression to the root tip improves the efficacy of the defence mechanism. However, a promoter that will provide root tip specific expression of transgenes in a monocot plant, such as plantain, is not currently available. Here, we report the cloning and evaluation of the maize root cap-specific protein-1 (ZmRCP-1) promoter for root tip targeted expression of transgenes that provide a defence against plant parasitic nematodes in transgenic plantain. Results Our findings indicate that the maize ZmRCP-1 promoter delivers expression of β-glucuronidase (gusA) gene in roots but not in leaves of transgenic plantains. In mature old roots, expression of gusA gene driven by ZmRCP-1 becomes limited to the root cap. Invasion by the nematode Radopholus similis does not modify Root Cap-specific Protein-1 promoter activity. Conclusions Root cap-specific protein-1 promoter from maize can provide targeted expression of transgene for nematode resistance in transgenic plantain

Biogeochemical processes and the diversity of Nhecolândia lakes, Brazil

The Pantanal of Nhecolândia, the world's largest and most diversified field of tropical lakes, comprises approximately 10,000 lakes, which cover an area of 24,000 km² and vary greatly in salinity, pH, alkalinity, colour, physiography and biological activity. The hyposaline lakes have variable pHs, low alkalinity, macrophytes and low phytoplankton densities. The saline lakes have pHs above 9 or 10, high alkalinity, a high density of phytoplankton and sand beaches. The cause of the diversity of these lakes has been an open question, which we have addressed in our research. Here we propose a hybrid process, both geochemical and biological, as the main cause, including (1) a climate with an important water deficit and poverty in Ca2+ in both superficial and phreatic waters; and (2) an elevation of pH during cyanobacteria blooms. These two aspects destabilise the general tendency of Earth's surface waters towards a neutral pH. This imbalance results in an increase in the pH and dissolution of previously precipitated amorphous silica and quartzose sand. During extreme droughts, amorphous silica precipitates in the inter-granular spaces of the lake bottom sediment, increasing the isolation of the lake from the phreatic level. This paper discusses this biogeochemical problem in the light of physicochemical, chemical, altimetric and phytoplankton data.<br>O Pantanal da Nhecolândia é o maior e mais diversificado campo de lagos da região tropical do planeta, com cerca de 10.000 lagos de variadas salinidade, pH, alcalinidade, cor, fisiografia e atividade biológica dispostos em uma área de 24.000 km². Os lagos hipossalinos têm pH variável, baixa alcalinidade, macrófitas e baixa densidade de fitoplâncton. Os lagos salinos tem pH acima de 9 ou 10, elevada alcalinidade, alta densidade de fitoplâncton e praias de areia. A causa da diversidade desses lagos é uma questão ainda em aberto que é abordada nesta pesquisa. Propõe-se como principal causa um processo híbrido, geoquímico e biológico, baseado em (1) clima com um déficit hídrico importante e pobreza em Ca2+na água superficial e do freático e (2) na elevação do pH durante florações de cianobactérias. Estes dois aspectos desestabilizam a tendência geral de pH neutro para as águas superficiais da Terra. Este desequilíbrio resulta em aumento do pH e dissolução da areia quartzosa do fundo dos lagos salino-alcalinos. Durante secas extremas há precipitação de sílica amorfa nos espaços inter-granulares dos sedimentos de fundo destes lagos, aumentando seu isolamento do freático. O artigo discute este processo biogeoquímico, à luz de dados físico-químicos, químicos, fitoplânctonicos e de altimetria de precisão