ZResponse to selection,heritability and genetic correlations between body weight and body size in Pacific white shrimp,Litopenaeus vannamei

To quantify the response to selection,heritability and genetic correlations between weight and size of Litopenaeus vannamei,the body weight (BW),total length (TL),body length (BL),first abdominal segment depth (FASD),third abdominal segment depth (TASD),first abdominal segment width (FASW),and partial carapace length (PCL) of 5-month-old parents and of offspring were measured by calculating seven body measurings of offspring produced by a nested mating design.Seventeen half-sib families and 42 full-sib families ofL.vannamei were produced using artificial fertilization from 2-4 dams by each sire,and measured at around five months post-metamorphosis.The results show that heritabilities among various traits were high:0.515士0.030 for body weight and 0.394士0.030 for total length.After one generation of selection,the selection response was 10.70% for offspring growth.In the 5"' month,the realized heritability for weight was 0.296 for the offspring generation.Genetic correlations between body weight and body size were highly variable.The results indicate that external morphological parameters can be applied during breeder selection for enhancing the growth without sacrificing animals for determining the body size and breed ability;and selective breeding can be improved significantly,simultaneously with increased production.

ISOLATION OF PLASMID FROM THE BLUE-GREEN ALGA SPIRULINA PLATENSIS

CCC plasmid was isolated from an economically important blue-green alga- Spirulina platensis (1.7×106 dalton from the S6 strain and 1.2×106 dalton from the F, strain) using a rapid method based on ultrasonic disruption of algal cells and alkaline removal of chromosomal DNA. The difference in the molecular weight of the OOC DNAs from the two strains differing in form suggests that plasmid may be related with the differentiation of algal form. This modified method, which does not use any lysozyme, is a quick and effective method of plasmid isolation, especially for filamentous blue-green algae.

Molecular cloning and expression analysis of Crustin-like gene from Chinese shrimp Fenneropenaeus chinensis

A new member of antimicrobial protein genes of the Crustin family was cloned from haemocytes of the Chinese shrimp Fennero- penaeus chinensis by 3 ′and 5′ RACE. The full-length cDNA of Crustin-like gene contains a 390 bp open reading frame, encoding 130 amino acids. The deduced peptide contains a putative signal peptide of 17 amino acids and mature peptide of 113 amino acids. The molecular mass of the deduced mature peptide is 12. 3 ku. It is highly cationic with a theoretical isoelectric point of 8.5. The deduced amino acids sequence of this Crustin showed high homology with those of Penaeus （ Litopenaeus ） setferus. Northern blotting showed that the cloned Crustin gene was mainly expressed in haemocytes, gill, intestine, and RNA in situ hybridization indicated that the Crustin gene was constitutively expressed exclusively in haemocytes of these tissues. Capillary elec- trophoresis RT-PCR analysis showed that Crustin was up-regulated dramatically from 12 to 48 h after a brief decrease of mRNA during first 6 h in response to microbe infection. The level of Crustin mRNA began to restore at 72 h post-challenge. This indicated that Crustin gene might play an important role when shrimps are infected by bacterial pathogen.

Preparation and Identification of Monoclonal Antibodies Against Vibrio anguillarum

Monoclonal antibodies (Mabs) against V.anguillarum strain M3 are prepared, and their isotypes are also characterized. Among them, C1C5 is the only Mab which does not crossreact with other eleven non-V.anguillarum strains. The proteinase K digestion test shows that the epitopes recognized by C1C5, C6C3 and C6C32 Mabs contained protein. The periodate oxidation test showed that the epitopes recognized by Mabs except C1C5 are glycosylated. In addition, results of additivity test indicate that the epitopes recognized by C6C3 and C6C32 Mabs are similar, and quite different from those recognized by Mab C1C5.

Isolation and Identification of Arbuscular Mycorrhizal Fungi from Agricultural Fields of Vietnam

The rising claim for more environmental friendly and healthy agriculture is a strong incentive to find alternative strategies to replace the use of mineral fertilizer and pesticide. Arbuscular mycorrhizal fungi (AMF), a main component of soil microbiota, represent a promising tool as providers of key ecological services. The present work represented one of the first attempts to study, under a morphological and molecular point of view, the AMF communities associated to some strategic crops in Vietnam. The findings about the AMF morphotypes dominant in different crop systems could be a starting point for the development of well performing and adapted inocula suitable for the application in field.

Selection for growth performance of tank-reared Pacific white shrimp, Litopenaeus vannamei

Seven growth-related traits were measured to assess the selection response and genetic parameters of the growth of Pacific white shrimp, Litopenaeus vannamei, which had been domesticated in tanks for more than four generations. Phenotypic and genetic parameters were evaluated and fitted to an animal model. Realized response was measured from the difference between the mean growth rates of selected and control families. Realized heritability was determined from the ratio of the selection responses and selection differentials. The animal model heritability estimate over generations was 0.44±0.09 for body weight (BW), and ranged from 0.21±0.08 to 0.37±0.06 for size traits. Genetic correlations of phenotypic traits were more variable (0.51-0.97), although correlations among various traits were high (>0.83). Across generations, BW and size traits increased, while selection response and heritability gradually decreased. Selection responses were 12.28%-23.35% for harvest weight and 3.58%-13.53% for size traits. Heritability estimates ranged from 0.34±0.09 to 0.48±0.15 for harvest weight and 0.17±0.01-0.38±0.11 for size traits. All phenotypic and genetic parameters differed between various treatments. To conclude, the results demonstrated a potential for mass selection of growth traits in L. vannamei. A breeding scheme could use this information to integrate the effectiveness constituent traits into an index to achieve genetic progress.

An acidic polysaccharide with xylose branches from Porphyra yezoensis

An acidic polysaccharide (PY3) was isolated from the hot water extract of the red algae Porphyra yezoensis by successive column chromatographies over DEAE-cellulose and Sephadex G-200. PY3 with an average molecular weight of 1.8×105 was demonstrated to be composed of galactose (Gal), 3,6-anhydrogalactose (3,6-AnGal), 6-OSO3-galactose (6-OSO3-Gal) and xylose (Xyl) in an approximate molar ratio of 25:15:10:1. In view of Smith degradation and me-thylation and on the basis of spectral evidence including those of IR, GC, GC-MS, and 1H and 13C NMR, the most probable repeating unit of PY3 could be proposed as [(1-3)β-D-Gal(1- 4)α-L-3,6-AnGal]3-[1-3)β-D-Gal(1-4)α-L-6-OSO3-Gal]2 with a xylose moiety at the C6 of one of every twenty-five β-D-Gal residues. To our knowledge, PY3 was shown to be the first porphyran possessing occasional xylose branches.

Foreign gene transfer into Chinese shrimps (Penaeus chinensis) with gene gun

Plasmids pG DNA-RZ1 with a GFP (green fluorescent protein) reporter gene and a ribozyme gene incising penaeid white spot baculovirus (WSBV) were first introduced into the fertilized eggs of Chinese shrimps by gene gun. The treated and control samples of different development stages were observed with a fluorescent microscope. The transient expression of GFP gene was high in nauplius and zoea larvae. Results from RT-PCR and PCR for adults showed that the foreign genes had been transferred into the shrimps and had expressed the corresponding proteins. This work has established a transgenic method for penaeid shrimps, which will set base for the application of genetic engineering breeding into industry.

DISTRIBUTION OF SOMATOSTATIN IN AMPHIOXUS——A STUDY OF IMMUNOHISTOCHEMISTRY

Somatostatin (SST)is a polypeptide isolated originally from the ovine hypothalamus. In recent years, using immunocytochemistry technique, many investigators demonstrated that SST widely distributed in the gastro-intestinal tract, islet, hypothalamus and pituitary gland of the vertebrates, while considering that SST might play an important physiological role in the vertebrate, such as the control of growth hormone and thyrotropin release from the anterior pituitary gland. However, the amphioxus is a transitional form of organism in

Roles of dysregulated Notch pathway and small DNA tumor viruses in cancer initiation and progression

Notch pathway is a major determinant of cell fate,and research within the last 30 years has shown dysfunctions within this pathway in the majority of solid tumors and leukemias.The molecular mechanisms causing aberrant expression of Notch in cancer are still partially known.Mesotheliomas,breast,and cervical cancers are among the cancer types for which the dysregulation of Notch has been reported together with the association of simian virus 40(SV40)or human papilloma virus(HPV)infections.In mesotheliomas and cervical cancer,there is clear evidence that these viruses cause and rely on dysregulation of the Notch pathway to promote and sustain cell transformation.The existence of a relationship in tumors between DNA viruses and Notch could have an impact on cancer therapy by implementing Notch inhibition to interfere with the growth of SV40-and HPV-positive cancers.In addition,since Notch links innate and acquired immunity and plays a key role in the regulation of the anti-viral response,targeting Notch in the presence of oncogenic viruses infections may help prevent the onset and progression of cancers associated with the exposure to these viruses.