Improvement of cell growth in green algae Chlamydomonas reinhardtii through co-cultivation with yeast Saccharomyces cerevisiae

PURPOSE

CO2 fixation methods using green algae have attracted considerable attention because they can be applied for the fixation of dilute CO2 in the atmosphere. However, green algae generally exhibit low CO2 fixation efficiency under atmospheric conditions. Therefore, it is a challenge to improve the CO2 fixation efficiency of green algae under atmospheric conditions. Co-cultivation of certain microalgae with heterotrophic microorganisms can increase the growth potential of microalgae under atmospheric conditions. The objective of this study was to determine the culture conditions under which the growth potential of green algae Chlamydomonas reinhardtii is enhanced by co-culturing with the yeast Saccharomyces cerevisiae, and to identify the cause of the enhanced growth potential.

RESULTS

When C. reinhardtii and S. cerevisiae were co-cultured with an initial green algae to yeast inoculum ratio of 1:3, the cell concentration of C. reinhardtii reached 133 × 105 cells/mL on day 18 of culture, which was 1.5 times higher than that of the monoculture. Transcriptome analysis revealed that the expression levels of 363 green algae and 815 yeast genes were altered through co-cultivation. These included genes responsible for ammonium transport and CO2 enrichment mechanism in green algae and the genes responsible for glycolysis and stress responses in yeast.

CONCLUSION

We successfully increased C. reinhardtii growth potential by co-culturing it with S. cerevisiae. The main reasons for this are likely to be an increase in inorganic nitrogen available to green algae via yeast metabolism and an increase in energy available for green algae growth instead of CO2 enrichment.

UV mutagenesis improves growth potential of green algae in a green algae-yeast co-culture system

It is known that co-cultivation of green algae with heterotrophic microorganisms, such as yeast, improves green algae's growth potential and carbon dioxide fixation, even under low CO2 concentration conditions such as the atmosphere. Introducing mutations into green algae is also expected to enhance their growth potential. In this study, we sought to improve the growth potential of a co-culture system of the green algae Chlamydomonas reinhardtii and the yeast Saccharomyces cerevisiae by introducing mutations into the green algae. Additionally, we performed a transcriptome analysis of the co-culture of the green algae mutant strain with yeast, discussing the interaction between the green algae mutant strain and the yeast. When the green algae mutant strain was co-cultured with yeast, the number of green algae cells reached 152 × 105 cells/mL after 7 days of culture. This count was 2.6 times higher than when the wild-type green algae strain was cultured alone and 1.6 times higher than when the wild-type green algae strain and yeast were co-cultured. The transcriptome analysis also indicated that the primary reason for the increased growth potential of the green algae mutant strain was its enhanced photosynthetic activity and nitrogen utilization efficiency.

[Quantitative measurement and clinical analysis of serum levels of immunosuppressive acidic protein (IAP) in hematopoietic malignancies]

Serum levels of immunosuppressive acidic protein (IAP) in 105 patients with hematopoietic malignancies, there were 12 cases of acute myeloblastic leukemia, 1 acute monocytic leukemia, 13 myelomonocytic leukemia, 4 acute promyelocytic leukemia, 26 chronic myelogenous leukemia, 22 non-Hodgkin's lymphoma, 5 Hodgkin's disease, 6 adult T-cell leukemia, 5 acute lymphoblastic leukemia, 3 chronic lymphocytic leukemia, and 8 multiple myeloma. High levels of serum IAP were detected in all of the patients except chronic phase of CML, malignant lymphoma in stage I and II, and multiple myeloma. In the cases of malignant lymphoma, serum IAP levels in stage III and IV were higher with statistical significance (p less than 0.01) than those in stage I and II. Serum IAP levels in the patients with CML in blastic crisis were higher than in the chronic phase, so serum IAP levels are useful as one diagnostic parameters in blastic crisis. However, in patients with ANLL in relapse, serum IAP levels showed normal values. Serum IAP levels paralleled those of acute phase reactants such as alpha 1-acid glycoprotein , C-reactive protein, alpha 2-globulin, and alpha 1-antitrypsin, and had inverse correlations with PPD and PHA skin test.

[Clinical experience with cefoxitin in infections associated with hematopoietic disorders]

Ten inpatients at the Second Department of Internal Medicine, Mie University Hospital, developed infections in the course of treatment for hematopoietic disorders and were administered cefoxitin (CFX). Patients suffered from the following infections: pharyngitis, 2; bronchitis, 2; pneumonia, 2; sepsis, 2; bacteremia, 1; suspected cases of bacteremia, 2; and fever of unknown origin, 1. The number of infections totaled 12 as 1 patient with pharyngitis also developed sepsis and 1 patient with pneumonia developed bacteremia. Duration for the administration of CFX ranged between 5 and 18 days with a total dosage of between 30 and 108 g. Of the 10 patients treated with CFX, 9 were treated concomitantly with micronomicin (MCR), doxycycline (DOXY), or sulbenicillin (SBPC), some were treated concomitantly with only 1 of the drugs and some were treated concomitantly with 2 of the drugs. The following clinical results were obtained: Following treatment, 4 patients were considered "excellent", 5, "good", and 3, "poor". Clinical efficacy rate was 75%. Four strains of Gram-positive cocci (1 strain of S. aureus, 2 strains of S. epidermidis and 1 strain of Streptococcus sp.) and 3 strains of Gram-negative rods (2 strains of P. aeruginosa and 1 strain of E. cloacae) were found in the clinical specimens of the 10 patients. These results differed somewhat from reported data that Gram-negative rods such as E. coli, Klebsiella sp., Pseudomonas sp., Serratia sp., are dominant. No serious side effects requiring cessation of treatment were observed. Elevations in the levels of S-GOT, S-GPT, serum alkaline phosphatase, blood urea nitrogen, etc. were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Coagulant and fibrinolytic activities in the leukemic cell lysates

We attempted to examine procoagulant activity (PCA), X activator activity (XAA) and plasminogen activator activity (PlgAA) of various leukemic cell lysates: 17 acute myelocytic leukemias (AML), 4 acute promyelocytic leukemias (APL), 9 acute myelomonocytic leukemias (AMMoL), 7 chronic myelocytic leukemias (CML), 4 CML with blastic crisis, 7 T cell acute lymphocytic leukemias (ALL), 8 adult T cell leukemias (ATL), 8 null cell ALL, 6 B cell lymphocytic leukemias. Among those 70 cases, 4 APL, 4 AMMoL and 5 AML were associated with overt disseminated intravascular coagulation (DIC) and 5 T cell ALL, 7 ATL and 2 null cell ALL were associated with hypofibrinogenemia not adapted for DIC. The sample used was the lysate of 10(7) cells. PCA was measured by recalcification time of normal plasma with the cell lysate, XAA and PlgAA was measured by chromogenic substrate. APL and AML, especially those associated with overt DIC, had high PCA, and lymphocytic leukemia generally had low PCA in comparison with normal controls. Total PCA (PCA multiplied by cell count/microliter) was remarkably increased in DIC and mildly increased in ALL with hypofibrinogenemia. The change in XAA and total XAA (XAA multiplied by cell count/microliter) was not remarkable in any leukemia except for T cell ALL and null cell ALL with hypofibrinogenemia. PlgAA was high in lymphocytic leukemias with hypofibrinogenemia, APL and AMMoL with DIC. Total PlgAA (PlgAA multiplied by cell count/microliter) was high especially in T cell ALL and null cell ALL with hypofibrinogenemia. Thus it is probable that PCA is the most important factor causing DIC in myelogenous leukemia and that PlgAA is the most important factor causing hypofibrinogenemia in lymphocytic leukemia. The measurement of these activities in the leukemic cells is valuable in prediction and prevention of the hemostatic disorder in leukemia.

[Treatment of infection in the patients wih hematopoietic malignancy with ceftezole (Falomesin) (author's transl)]

Ceftezole (CTZ) was administered to 20 patients with hematopoietic malignancy complicated with infections. These patients consisted of 7 cases of AML, 2 ALL, 2 AMMoL, 1 APL, 1 blast crisis of CML, 2 HD, and 5 NHL. In 13 cases, sites of infection were determined and causative organisms were identified. In other 7 cases, sites of infection or causative organisms were unknown. In the former 13 cases, pneumonia was demonstrated in 6 patients, tonsillitis in 4 patients, pyelonephritis in 2 patients and sepsis in 1 patient. Klebsiella was separated from 5 patients as the causative organisms, E. coli from 2 patients, E. coli and Pseudomonas aeruginosa from 1 patient, Pseudomonas cepacia from 1 patient, Streptococcus viridans from 2 patients, Proteus from 1 patient and Torulopsis from 1 patient. Gram-negative rods were separated from 10 of the 13 cases (77%) as the causative organisms. CTZ was administered intravenously in dose from 4 g to 16 g per day combined with other antibiotics (AMK, GM, DKB, TOB, SBPC, CBPC, LC, ST). The response rate in 12 cases of acute leukemia and in 7 cases of malignant lymphoma was 58% and 43%, respectively. Infections occurred in 4 patients with less than 100 neutrophil per mm3 did never favorably responded even with CTZ.