Chitosan-coated alginate micro-particles delivery of active principles through conventional pelleted food - A study in Tilapia (Oreochromis niloticus).

The search for alternatives to antibiotics in aquaculture has focused on the use of vaccines for immune-prophylaxis. The purpose of this study was to examine the feasibility and characteristics of chitosan-alginate microparticles for the oral delivery of immune-prophylactics to finfish. The microparticles, which incorporate fluorescent-labelled lysozyme, were produced by spray-drying method; their structural properties and uptake from the gastrointestinal tract of Tilapia (Oreochromis niloticus) were assessed by microscopy. The main findings show that the microparticles are able to retain their content in an acidic environment and to release it later in slightly alkaline conditions such as those found in the intestines. Moreover, both the microencapsulation procedure and the biopolymers used have no deleterious impact on the lysozyme lytic activity, which is maintained after the protein has been released from the microparticles. Administered in vivo in Tilapia by medicated food, the microparticles transit unaffected through the stomach, and reach the anterior intestines, in particular the villum sectum and the basal lamina of epithelial cells, 2 and 4 h after feeding. Overall, the evidence obtained here supports the potential of these chitosan-alginate microparticles as agents for oral immune-prophylaxis in the management of fish diseases.

New steps in the control of canine rabies in India.

In India, about 20,000 people die of rabies every year. The dog is the main reservoir and transmitter of the disease. A pilot rabies control programme was launched in five Indian federal states in February, 2007. This initiative is led by the Animal Welfare Board of India (AWBI) federating many animal welfare organizations and the Ministry of Agriculture. It aims at creating a "Rabies Free India." The programme combines parenteral vaccination of accessible owned and stray dogs, spaying/neutering followed by parenteral vaccination and oral vaccination of inaccessible dogs. The freeze-dried vaccine SAG2, including the bait casing, was registered in India following successful evaluation of vaccine-bait safety and efficacy (by survival after virulent challenge) in captive Indian stray dogs in the Bhopal High Security Animal Disease Laboratory. Furthermore, bait acceptance was tested under both experimental and field conditions.

The safety and efficacy of the oral rabies vaccine SAG2 in Indian stray dogs.

India is one of the countries with the highest prevalence of human rabies throughout the world. Dogs are primarily responsible for rabies transmission. Among them, stray dogs play a major role in that country. Parenteral vaccination programmes are insufficient to eliminate rabies partly due to difficulties in establishing satisfactory immunisation coverage in the dog population in view of the high proportion of stray dogs. Oral vaccination may be a useful adjunct to parenteral vaccination by increasing dog vaccination coverage. Safety, immunogenicity and efficacy of Rabidog SAG2 bait were evaluated in Indian stray dogs in captivity. Safety of SAG2 was demonstrated by the absence of adverse clinical sign, salivary excretion and absence of replication of the vaccine strain in brain and salivary glands of 21 vaccinated dogs, even when immunodepressed. Efficacy was shown 109 days post-vaccination after challenge with a highly virulent street rabies virus which killed all five controls whereas all nine vaccinated dogs survived, despite the fact that only five out of nine had seroconverted before challenge.

Cloning of human 2H9 heterogeneous nuclear ribonucleoproteins. Relation with splicing and early heat shock-induced splicing arrest.

Using antibody 2H9 from our heterogeneous nuclear ribonucleoproteins (anti-hnRNP) monoclonal antibody library, we previously showed in HeLa cells that a 35-37-kDa protein doublet switches from the hnRNP complexes to the nuclear matrix following a 10-min heat shock at 45 degrees C (1 Lutz, Y., Jacob, M., and Fuchs, J. P. (1988) Exp. Cell Res. 175, 109-124). cDNA cloning and sequencing revealed an hnRNP protein (2H9) which is a new member of the hnRNP F, H/H' family. Protein 2H9 displays two consensus sequence-type RNA binding domains (CS-RBD) showing 80-90% homology with two of the three CS-RBDs of hnRNP F and H/H'. Another common feature is the presence of two glycine/tyrosine-rich auxiliary domains located at the C terminus and between the two CS-RBDs. At the functional level we show that specific anti-2H9 peptide antibodies can directly inhibit an in vitro splicing system. Moreover, the 2H9 protein doublet is no more present in nuclear extracts from such briefly stressed cells, which interestingly correlates with the inability of these extracts to catalyze in vitro splicing reactions. Taken together, our data suggest that these proteins are involved in the splicing process and also participate in early heat shock-induced splicing arrest by transiently leaving the hnRNP complexes. These 2H9 proteins, which are encoded by a single gene located on human chromosome 10, were also found to be associated with nuclear bodies in situ.

Asymptomatic carriers of Babesia canis in an enzootic area. / Etude du portage asymptomatique de Babesia canis en zone d'enzootie.

Dogs latently infected with Babesia canis were systematically detected amongst a population kept in an enzootic area over a year. Detection of parasite was carried out on 43 healthy dogs and identified by two blood cultures in an interval of a few months. A serological study was performed using indirect immunofluorescence and Western blot. This study distinguished two distinct groups: asymptomatic carrier dogs (latently infected or premunised-33%) and non-carrier dogs with sterilising immunity. There is no difference between carrier and non-carrier dogs concerning age, breed or history of babesial infection and 36 out of the 43 dogs studied are seropositive. The antibody titer did not completely correlate with the detection of parasitaemia. All carrier dogs are seropositive to Babesia canis, but half of the seropositive dogs are not carriers. This study confirms that serological detection is not a good indicator of latent babesial infection. This study did not detect any difference between antibody responses (quantitative response (IIF) or qualitative response (WB)), related to latent parasitaemia.

The human hnRNP-M proteins: structure and relation with early heat shock-induced splicing arrest and chromosome mapping.

With anti-hnRNP monoclonal antibody 6D12 we previously showed in HeLa cells that as early as 10 min after the onset of a heat shock at 45 degrees C, a 72.5-74 kDa antigen doublet leaves the hnRNPs and strongly associates with the nuclear matrix, the effect being reversed after a 6 h recovery at 37 degrees C. cDNA cloning and sequencing enabled us to identify these antigens as hnRNP-M proteins and further to show that the correct sequence differs by an 11 amino acid stretch from the originally published sequence. We also show that monoclonal antibodies raised against synthetic hnRNP-M peptides can directly inhibit in vitro splicing. Furthermore, stressing cells at 45 degrees C for 10 min is sufficient to abolish the splicing capacity of subsequently prepared nuclear extracts which, interestingly, do not contain the hnRNP-M proteins any more. Taken together, our data suggest that these proteins are involved in splicing as well as in early stress-induced splicing arrest. Further in situ hybridization assays located the hnRNP-M encoding gene on human chromosome 19.

Babesia canis: evidence for genetic diversity among isolates revealed by restriction fragment length polymorphism analysis.

The genetic diversity of B. canis was investigated by restriction fragment length polymorphism analysis. For this purpose, we identified a Babesia canis specific DNA probe named pS8. This 1.2 kbp probe can detect as low as 20 pg of B. canis DNA. Results suggest that the pS8 probe is distributed in multiple copies throughout the genome though is probably not itself internally repetitious, i.e. not structured into blocks of tandem units. This probe reveals discrete hybridizing fragments in B. canis enzyme-digested genomic DNA. RFLP patterns obtained with the pS8 probe revealed a large genetic diversity between various isolates and led us to distinguish several clones derived from a single isolate. Results suggest that for a single isolate, the fingerprints obtained reflect those of a few quantitatively dominant clones. This technique can now be routinely applied and provides a convenient tool for the characterization and the identification of B. canis isolates, strains and clones.

Rapid effect of heat shock on two heterogeneous nuclear ribonucleoprotein-associated antigens in HeLa cells.

During severe heat shock, which known to interrupt both splicing of RNA transcripts and nucleocytoplasmic transport, it is to be expected that the substructure of heterogeneous nuclear ribonucleoproteins (hnRNP) is altered in some way. Recently, we have shown that such a stress actually induces rapid alterations at the level of individual proteins (Lutz, Y., M. Jacob, and J.-P. Fuchs. 1988 Exp. Cell Res. 175:109-124). Here we report further investigations on two related 72.5-74-kD hnRNP proteins whose behavior is also rapidly modified by a heat shock at 45 degrees C, whereas no effect is observed at 42 degrees C. Using a monoclonal antibody, we show that in situ the antigens are available only when the cells are heat shocked at 45 degrees C. Subcellular fractionation shows that in normal cells the antigens are associated with the bulk of hnRNP (50-200S). During heat shock, whereas the overall characteristics of the bulk of preexisting hnRNP are unchanged, these antigens rapidly switch to a subpopulation of hnRNP with larger average size (50 to less than 300S) and increased stability. Structural analysis of the associated hnRNP in normal and stressed cells shows that in both cases the antigens are associated with the nuclear matrix subcomplex of hnRNP, which in situ is part of the internal nuclear matrix. Such hnRNP antigens, which are rapidly redistributed during a heat shock at the upper temperature range of the stress response, might well be involved in splicing and/or transport control.

A new homeo-box is present in overlapping cosmid clones which define the mouse Hox-1 locus.

A new murine homeo-box (Hox1-3) has been isolated and studied with respect to its structure and transcriptional pattern. This homeo-box is part of a gene which is specifically regulated during mouse prenatal development and expressed in a restricted number of teratocarcinoma tumours as well as in adult testis. Hox1-3 is shown to be a member of a cluster of at least four homeo-boxes lying within a 75-kb segment of DNA on mouse chromosome 6. The structure of the whole cluster, the Hox-1 locus is presented.