Establishment of a basic method for manipulating preantral follicles: effects of retrieval method on in vitro growth of preantral follicles and intrafollicular oocytes

The aim of this study was to establish a basic manipulation protocol of preantral follicles for deriving developmentally competent oocytes. Primary, early and late secondary follicles retrieved from the ovaries of 14-day-old F1 (C57BL/6 x DBA2) female mice mechanically or enzymatically were cultured singly and in vitro growth of the follicles and maturation of intrafollicular oocytes were subsequently monitored. A mechanical method retrieved more (p < 0.0001) follicles (339 +/- 48 vs. 202 +/- 28) than an enzymatic method. However, the enzymatic method collected more singly isolated follicles that could be provided for subsequent culture (102 +/- 26 vs. 202 +/- 28). When an enzymatic method was employed, early and late secondary follicles required 9 and 6 days for reaching the maximal incidence of the pseudoantral stage. However, primary follicles were not possible to develop into the pseudoantral stage. The optimal duration of oocyte maturation from the onset of follicle culture was 7 days and 5-7 days for early and late secondary follicles, respectively. A general decrease in oocyte diameter (65.2-65.53 microm vs. 75 microm) and zona thickness (5.41-5.74 microm vs. 7.76 microm) was detected in in vitro-derived compared with in vivo-derived matured oocytes. Pronuclear formation was detected in 86-94% of mature oocytes after parthenogenetic activation and no significant difference was detected among groups. These results showed that preantral follicles retrieved by an enzymatic method underwent step-by-step growth in vitro, which could yield mature oocytes.     

Combination of the tod and the tol pathways in redesigning a metabolic route of Pseudomonas putida for the mineralization of a benzene, toluene, and p-xylene mixture.

Construction of a hybrid strain which is capable of mineralizing components of a benzene, toluene, and p-xylene mixture simultaneously was attempted by redesigning the metabolic pathway of Pseudomonas putida. Genetic and biochemical analyses of the tod and the tol pathways revealed that dihydrodiols formed from benzene, toluene, and p-xylene by toluene dioxygenase in the tod pathway could be channeled into the tol pathway by the action of cis-p-toluate-dihydrodiol dehydrogenase, leading to complete mineralization of a benzene, toluene, and p-xylene mixture. Consequently, a hybrid strain was constructed by cloning todC1C2BA genes encoding toluene dioxygenase on RSF1010 and introducing the resulting plasmid into P. putida mt-2. The hybrid strain of P. putida TB105 was found to mineralize a benzene, toluene, and p-xylene mixture without accumulation of any metabolic intermediate.     

Harvesting of Spirulina platensis by cellular flotation and growth stage determination

AIM: To investigate an effective harvesting method for Spirulina platensis. METHODS AND RESULTS: Eighty per cent of S. platensis cells in the logarithmic growth phase were harvested by flotation when the cells were set in a static condition for 2 h. The optimum harvesting time was about day 6 of cultivation. The flotation activity of S. platensis cells was enhanced by the addition of NaCl. CONCLUSIONS: The harvesting of S. platensis by flotation is a cost-effective and straightforward method that can retain the algal quality. The optimum harvesting time of S. platensis can be predicted by the cellular protein to carbon ratio. SIGNIFICANCE AND IMPACT OF THE STUDY: Flotation harvesting is also applicable to other cyanobacteria with gas vesicles.     

Genome Sequence of Pectobacterium carotovorum subsp. carotovorum Strain PCC21, a Pathogen Causing Soft Rot in Chinese Cabbage

Pectobacterium carotovorum is a plant-pathogenic enterobacterium responsible for soft rot in various commercially important plants. Here we report the complete genome sequence and automatic annotation of strain PCC21.     

Phosphorylation-dependent cleavage of p130cas in apoptotic rat-1 cells

We previously demonstrated caspase-mediated cleavage of p130cas during apoptosis and identified two caspase-3 cleavage sites [1]. In this study, we investigated the phosphorylation-dependent cleavage of p130cas in apoptotic Rat-1 fibroblast cells. Lysophosphatidic acid and fibronectin induced p130cas phosphorylation, which in turn resulted in resistance to caspase-mediated cleavage. Alternatively, dephosphorylation by calf intestinal alkaline phosphatase, PP1, and LAR stimulated cleavage of p130cas by caspase-3, generating a 31-kDa fragment. During apoptosis, p130cas dephosphorylation seems to precede its cleavage. The phosphorylation of tyrosine and serine residues immediately adjacent to the two cleavage sites (DVPD(416) and DSPD(748)) strongly affected p130cas cleavage by caspase-3, both in vitro and in vivo. Furthermore, the generation of the 31-kDa cleavage fragment was strongly regulated by phosphorylation of a tyrosine residue at position 751 (DSPD(748) and GQY(751)). Our results collectively suggest that degradation of p130cas during apoptosis is modulated in a phosphorylation-dependent manner.     

Development of immunoassay methods by use of liposomes

In order to develop liposomes for use in an immunoassay system, the preparation of immune liposomes and their characterization have been investigated. Liposomes have potential use in extremely sensitive analytical immunoassays, in addition to serving as an attractive drug delivery system. This liposome immunoassay system is based on membrane immunochemistry and an enzymatic reaction. An intense yellow color, easily detectable with the naked eye, was produced quite rapidly by the lysis of bovine serum albumin (BSA)-labeled, alkaline phosphatase-entrapped liposomes in the presence of anti-BSA rabbit serum and active complement under alkaline conditions. Sensitive detection is possible because of the antigen-antibody complex reaction, which leads to liposome lysis and an enzymatic reaction. The liposome immunoassay method offers a rapid, simple, and sensitive testing procedure which can quantitatively and qualitatively determine the presence or absence of antigenic materials and antibodies.     

Antitumor therapeutic effects of e7 subunit and DNA vaccines in an animal cervical cancer model: antitumor efficacy of e7 therapeutic vaccines is dependent on tumor sizes, vaccine doses, and vaccine delivery routes

We previously reported that E7 subunit and DNA vaccines are both capable of inducing antitumor protection through induction of antigen-specific CTL. In this study, we investigated their ability to control established tumors according to tumor size, vaccine doses, and vaccine delivery routes. Antitumor therapeutic efficacy of both vaccine types was dependent on tumor burden. However, E7 subunit vaccines induced a higher level of antitumor therapeutic activities at the tested dose compared to DNA vaccines. This was concomitant with induction of antibody, CTL, and IFN-gamma responses, as well as histologic changes (heavy infiltration of lymphocytes and presence of apoptotic bodies). In vaccine dose titration assays, 50 and 100 microg of DNA vaccines exhibited an equivalent antitumor efficacy to 0.5 and 1 microg of E7 subunit vaccines, respectively, i.e., a 100-fold difference in E7 dosage, suggesting the importance of vaccine doses for achieving antitumor immunity. Furthermore, tumors of a larger size were controlled by intratumoral injection with E7 subunit vaccines, underscoring the importance of vaccine delivery routes for antitumor therapeutic efficacy. Thus, these data suggest that antitumor therapeutic efficacy of E7 therapeutic vaccines is determined by vaccine doses, vaccine delivery routes, and tumor sizes, and that these vaccines could be another addition to conventional therapy modalities against cervical cancer.