Expression of immune-related genes in one phase of embryonic development of freshwater crayfish, Pacifastacus leniusculus.
ABSTRACT Crayfish do not have larval stage as other crustacean such as penaeid shrimp they spawn their eggs until hatching and what hatches out from the eggs are miniature crayfish known as juveniles. In order to address the question whether immune genes are initially expressed during the embryo development in the egg stage, the expression of some immune-related genes: prophenoloxidase (proPO), peroxinectin, hemocyanin, anti-lipopolysaccharide factor (ALF), plcrustin, astakine-1, 2 and transglutaminase (TGase) were determined in the middle phase of crayfish embryo development. Furthermore, immune challenge was used to determine the immune response of eggs by immersing them in a solution of the highly pathogenic bacterium Aeromonas hydrophila. Semi-quantitative RT-PCR analysis showed that all tested genes are present except proPO in this phase of crayfish embryo development and none of the genes tested changed their expression following immersion in A. hydrophila. The proPO transcript has been reported from hemocytes in crustaceans and it plays crucial roles in crustacean immune response. This may indicate that the development of immune-competent hemocytes in this stage of crayfish embryo is not completed and the egg shell as such plays an important role as a shield in protecting the embryo from bacteria and maybe also other pathogens.
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ABSTRACT: Crustaceans are a large and diverse invertebrate animal group that mounts a complex and efficient innate immune response against a variety of microorganisms. The crustacean immune system is primarily related to cellular responses and the production and release of important immune effectors into the hemolymph. Antimicrobial proteins and/or peptides (AMPs) are key components of innate immunity and are widespread in nature, from bacteria to vertebrate animals. In crustaceans, 15 distinct AMP families are currently recognized, although the great majority (14 families) comes from members of the order Decapoda. Crustacean AMPs are generally cationic, gene-encoded molecules that are mainly produced by circulating immune-competent cells (hemocytes) or are derived from unrelated proteins primarily involved in other biological functions. In this review, we tentatively classified the crustacean AMPs into four main groups based on their amino acid composition, structural features and multi-functionality. We also attempted to summarize the current knowledge on their implication both in an efficient response to microbial infections and in crustacean survival.Invertebrate Survival Journal. 01/2010;
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ABSTRACT: This paper presents findings from a three-year, qualitative study of teachers enrolled in a Masters of Teacher Leadership program. Researchers sought to understand the ways teachers’ beliefs about and understandings of teacher leadership were affected by their participation in a formal teacher leadership program, as well as the kinds of actions they took up as a result of this participation. Data indicate three significant ways participants’ work as teacher leaders was developed and enhanced, including: (a) identifying and amplifying their professional voice, (b) deepening and extending their voice as they plan, and (c) reframing their work/shift responsibility through constructing widening circles of influence and impact. Authors identify implications of their research for growing teacher leaders, school improvement and change, changing school culture, enhancing student engagement, and building new structures.Teaching and Teacher Education - TEACH TEACH EDUC. 01/2011; 27(5):920-929.
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ABSTRACT: The author discusses their progress in investigating the influences of crystallographic orientation and of strain on the nonlinear and electro-optical properties of III-V semiconductor compounds, and they present examples of how these orientation-dependent properties can be used to design novel optical devices01/1996;