Pyrindicin,a New Alkaloid from a Streptomyces Strain

In the course of our examination for the alkaloid productivities of Streptomyces strains, Streptomyces sp. NA–15 was found to produce a new alkaloid, pyrindicin, in the culture medium. The strain NA–15 was found to be a variant of Streptomyces griseoflavus and was designated as S. griseoflavus var. pyr indie us nov. var.

After the culture conditions for pyrindicin production were studied, pyrindicin was obtained as its hydrochloride (mp 145°C, decomp.) from the cultured broth. The compound was shown to possess weak antimicrobial and several pharmacological activities. The LD₅₀ of the hydrochloride (ip, in mice) was 87 mg/kg.     

Psychological stress contributed to the development of low-grade fever in a patient with chronic fatigue syndrome: a case report

Background

Low-grade fever is a common symptom in patients with chronic fatigue syndrome (CFS), but the mechanisms responsible for its development are poorly understood. We submit this case report that suggests that psychological stress contributes to low-grade fever in CFS.

Case presentation

A 26-year-old female nurse with CFS was admitted to our hospital. She had been recording her axillary temperature regularly and found that it was especially high when she felt stress at work. To assess how psychological stress affects temperature and to investigate the possible mechanisms for this hyperthermia, we conducted a 60-minute stress interview and observed the changes in the following parameters: axillary temperature, fingertip temperature, systolic blood pressure, diastolic blood pressure, heart rate, plasma catecholamine levels, and serum levels of interleukin (IL)-1β and IL-6 (pyretic cytokines), tumor necrosis factor-α and IL-10 (antipyretic cytokines). The stress interview consisted of recalling and talking about stressful events. Her axillary temperature at baseline was 37.2°C, increasing to 38.2°C by the end of the interview. In contrast, her fingertip temperature decreased during the interview. Her heart rate, systolic and diastolic blood pressures, and plasma levels of noradrenaline and adrenaline increased during the interview; there were no significant changes in either pyretic or antipyretic cytokines during or after the interview.

Conclusions

A stress interview induced a 1.0°C increase in axillary temperature in a CFS patient. Negative emotion-associated sympathetic activation, rather than pyretic cytokine production, contributed to the increase in temperature induced by the stress interview. This suggests that psychological stress may contribute to the development or the exacerbation of low-grade fever in some CFS patients.

     

Glycosylation Status of CD43 Protein Is Associated with Resistance of Leukemia Cells to CTL-Mediated Cytolysis

To improve cancer immunotherapy, it is important to understand how tumor cells counteract immune-surveillance. In this study, we sought to identify cell-surface molecules associated with resistance of leukemia cells to cytotoxic T cell (CTL)-mediated cytolysis. To this end, we first established thousands of monoclonal antibodies (mAbs) that react with MLL/AF9 mouse leukemia cells. Only two of these mAbs, designated R54 and B2, bound preferentially to leukemia cells resistant to cytolysis by a tumor cell antigen–specific CTLs. The antigens recognized by these mAbs were identified by expression cloning as the same protein, CD43, although their binding patterns to subsets of hematopoietic cells differed significantly from each other and from a pre-existing pan-CD43 mAb, S11. The epitopes of R54 and B2, but not S11, were sialidase-sensitive and expressed at various levels on leukemia cells, suggesting that binding of R54 or B2 is associated with the glycosylation status of CD43. R54^high leukemia cells, which are likely to express sialic acid-rich CD43, were highly resistant to CTL-mediated cytolysis. In addition, loss of CD43 in leukemia cells or neuraminidase treatment of leukemia cells sensitized leukemia cells to CTL-mediated cell lysis. These results suggest that sialic acid-rich CD43, which harbors multiple sialic acid residues that impart a net negative surface charge, protects leukemia cells from CTL-mediated cell lysis. Furthermore, R54^high or B2^high leukemia cells preferentially survived in vivo in the presence of adaptive immunity. Taken together, these results suggest that the glycosylation status of CD43 on leukemia is associated with sensitivity to CTL-mediated cytolysis in vitro and in vivo. Thus, regulation of CD43 glycosylation is a potential strategy for enhancing CTL-mediated immunotherapy.     

Daily growth increments in otoliths of wild-caught honmoroko Gnathopogon caerulescens

Otolith growth increments in wild-caught alizarin complex one (ALC)-marked honmoroko Gnathopogon caerulescens were examined to verify the veracity of the age determination method in cyprinids. ALC-marked G. caerulescens recaptured from their natural environment had lapilli increment counts outside the ALC ring mark that had formed on a daily basis during the juvenile stage. This apparently being the first direct evidence of daily periodicity of otolith increment formation in wild-caught cyprinids.     

Circumnutational movement in rice coleoptiles involves the gravitropic response: analysis of an agravitropic mutant and space‐grown seedlings

Plants exhibit helical growth movements known as circumnutation in growing organs. Some studies indicate that circumnutation involves the gravitropic response, but this notion is a matter of debate. Here, using the agravitropic rice mutant lazy1 and space‐grown rice seedlings, we found that circumnutation was reduced or lost during agravitropic growth in coleoptiles. Coleoptiles of wild‐type rice exhibited circumnutation in the dark, with vigorous oscillatory movements during their growth. The gravitropic responses in lazy1 coleoptiles differed depending on the growth stage, with gravitropic responses detected during early growth and agravitropism during later growth. The nutation‐like movements observed in lazy1 coleoptiles at the early stage of growth were no longer detected with the disappearance of the gravitropic response. To verify the relationship between circumnutation and gravitropic responses in rice coleoptiles, we conducted spaceflight experiments in plants under microgravity conditions on the International Space Station. Wild‐type rice seeds were germinated, and the resulting seedlings were grown under microgravity or a centrifuge‐generated 1 g environment in space. We began filming the seedlings 2 days after seed imbibition and obtained images of seedling growth every 15 min. The seed germination rate in space was 92–100% under both microgravity and 1 g conditions. LED‐synchronized flashlight photography induced an attenuation of coleoptile growth and circumnutational movement due to cumulative light exposure. Nevertheless, wild‐type rice coleoptiles still showed circumnutational oscillations under 1 g but not microgravity conditions. These results support the idea that the gravitropic response is involved in plant circumnutation.     

A novel PDZ domain containing guanine nucleotide exchange factor links heterotrimeric G proteins to Rho

Small GTP-binding proteins of the Rho family play a critical role in signal transduction. However, there is still very limited information on how they are activated by cell surface receptors. Here, we used a consensus sequence for Dbl domains of Rho guanine nucleotide exchange factors (GEFs) to search DNA data bases, and identified a novel human GEF for Rho-related GTPases harboring structural features indicative of its possible regulatory mechanism(s). This protein contained a tandem DH/PH domain closely related to those of Rho-specific GEFs, a PDZ domain, a proline-rich domain, and an area of homology to Lsc, p115-RhoGEF, and a Drosophila RhoGEF that was termed Lsc-homology (LH) domain. This novel molecule, designated PDZ-RhoGEF, activated biological and biochemical pathways specific for Rho, and activation of these pathways required an intact DH and PH domain. However, the PDZ domain was dispensable for these functions, and mutants lacking the LH domain were more active, suggesting a negative regulatory role for the LH domain. A search for additional molecules exhibiting an LH domain revealed a limited homology with the catalytic region of a newly identified GTPase-activating protein for heterotrimeric G proteins, RGS14. This prompted us to investigate whether PDZ-RhoGEF could interact with representative members of each G protein family. We found that PDZ-RhoGEF was able to form, in vivo, stable complexes with two members of the Galpha12 family, Galpha12 and Galpha13, and that this interaction was mediated by the LH domain. Furthermore, we obtained evidence to suggest that PDZ-RhoGEF mediates the activation of Rho by Galpha12 and Galpha13. Together, these findings suggest the existence of a novel mechanism whereby the large family of cell surface receptors that transmit signals through heterotrimeric G proteins activate Rho-dependent pathways: by stimulating the activity of members of the Galpha12 family which, in turn, activate an exchange factor acting on Rho.     

Differential response of angiotensin peptides in the urine of hypertensive animals

Urinary excretion rates of angiotensin I (Ang I), angiotensin II (Ang II), and angiotensin-(1-7) [Ang-(1-7)] were determined in normotensive Sprague Dawley (SD), spontaneously hypertensive (SHR), and mRen-2 transgenic hypertensive animals before and following blockade of Ang II synthesis or activity for two weeks. This study was performed to determine for the first time whether inhibition of Ang II alters the excretion of angiotensin peptides in the urine. Rats were given either tap water or water medicated with lisinopril, losartan or both agents in combination. Blood pressure was monitored at regular intervals during the experiment by the tail-cuff method, and once again at the end of the study with a catheter implant into a carotid artery. Metabolic studies and 24 h urinary excretion variables and angiotensin peptides were determined before and during the procedures. While all three treatments normalized the blood pressure of hypertensive animals, therapy with either lisinopril or the combination of lisinopril and losartan had a greater antihypertensive effect in both SHR and [mRen-2]27 transgenic hypertensive rats. In the urine, the concentration of the angiotensins (normalized by 24-h creatinine excretion) was several-fold higher in the untreated hypertensive animals than in normotensive SD rats. In SD rats, lisinopril or lisinopril and losartan produced a sustained rise in urinary levels of Ang-(1-7) without changes in the excretion of Ang I and Ang II. In contrast, Ang I and Ang-(1-7) were significantly elevated in SHR medicated with lisinopril alone or in combination with losartan. Only losartan, however, augmented urinary levels of Ang II in the SHR. The antihypertensive effects of the three separate regimens had no effect on the urinary excretion of angiotensin peptides in [mRen-2]27 transgenic hypertensive rats. These data show that Ang I and Ang-(1-7) are excreted in large amounts in the urine of SD, SHR and [mRen-2]27 hypertensive rats. The unchanged Ang-(1-7) excretion in transgenic hypertensive (Tg+) rats after inhibition of the renin-angiotensin system agrees with the previous finding of a reduced plasma clearance of the peptide in this model of hypertension. The data suggest that this form of hypertension may be associated with increased activity of an endogenous converting enzyme inhibitor.     

Isolation of Orientia tsutsugamushi from patients in Shikoku and finding of a strain which grows preferentially at low temperatures

Three strains of Orientia tsutsugamushi were isolated from patients in Anan City, Tokushima Prefecture. The strains were identified as Karp type by analyses of reactivities with type-specific monoclonal antibodies. One strain, Okazaki, was isolated in L cells cultivated at 31 C, but not in cells at 36 C or in mice. This strain showed better growth at 31 C than 36 C. This is the first report of an O. tsutsugamushi strain which grows preferentially at low temperatures.     

Transient hyper-17-OHPnemia unrelated to cross-reactions with residual fetal adrenal cortex products

OBJECTIVE: To clarify the pathogenesis of transient hyper-17alpha-hydroxyprogesteronemia, we initiated a laboratory investigation in a pre-term infant with persistently high serum 17alpha-hydroxyprogesterone (17-OHP) until 2 months of age. METHODS: Serum 17-OHP level was measured by high-performance liquid chromatography and radioimmunoassay, and gene analysis of CYP21A2 (21-hydroxylase) was performed. RESULT: Serum 17-OHP level on the 29th day of life was 25.4 ng/ml, and the urinary steroid profile showed low pregnanetriolone. Gene analysis of 21-hydroxylase disclosed no mutation, and 17-OHP normalized by 3 months of age without specific treatment. CONCLUSION: Transient elevations in 17-OHP, which do not appear related to cross-reactions with products of a residual fetal adrenal cortex, may occur in the first few months of life.