Kasugamycin (KSM), an aminoglycoside antibiotic isolated from Streptomyces kasugaensis cultures, has been used against rice blast disease for more than 50 years. We cloned the KSM biosynthetic gene (KBG) cluster from S. kasugaensis MB273-C4 and constructed three KBG cassettes (i.e., cassettes I-III) to enable heterologous production of KSM in many actinomycetes by constitutive expression of KBGs. Cassette I comprised all putative transcriptional units in the cluster, but it was placed under the control of the P promoter from Tn5. It was not maintained stably in Streptomyces lividans and did not transform Rhodococcus erythropolis. Cassette II retained the original arrangement of KBGs, except that the promoter of kasT, the specific activator gene for KBG, was replaced with P , the constitutive promoter of rpsJ from Streptomyces avermitilis. To enhance the intracellular concentration of myo-inositol, an expression cassette of ino1 encoding the inositol-1-phosphate synthase from S. avermitilis was inserted into cassette II to generate cassette III. These two cassettes showed stable maintenance in S. lividans and R. erythropolis to produce KSM. Particularly, the transformants of S. lividans induced KSM production up to the same levels as those produced by S. kasugaensis. Furthermore, cassette III induced more KSM accumulation than cassette II in R. erythropolis, suggesting an exogenous supply of myo-inositol by the ino1 expression in the host. Cassettes II and III appear to be useful for heterologous KSM production in actinomycetes. Rhodococcus exhibiting a spherical form in liquid cultivation is also a promising heterologous host for antibiotic fermentation.
Pesticide residues in five freshwater areas that are directly affected by rice paddy effluents in southern Japan were measured to determine their maximum concentrations and temporal variations. Water samples were collected every week during the 2005 rice planting season in Kagoshima Prefecture and stations were established in Amori River, Sudo River, Nagaida River (that drains into the bigger Kotsuki River), rice paddy drainage canal, and wastewater reservoir (that collects effluents from rice paddy fields). Of the 14 target pesticides examined, a total of 11 were detected in all stations. Mefenacet, fenobucarb, and flutolanil were the three pesticides with the highest maximum concentrations and were also detected frequently. Analysis of temporal variations of pesticides showed that herbicides had relatively higher concentrations in the earlier stages of the rice planting season, while insecticides and fungicides had relatively higher concentrations at the later stages. There was no significant difference among stations with regards to the temporal patterns of the top three pesticides. The calculated toxic units were less than 1 in all stations, implying low or negligible environmental risk of pesticides detected to freshwater organisms.
Introduction:
Heart failure (HF) especially right-heart failure causes hepatic portal system congestion. The Portal vein (PV) pulsatility can be influenced by right atrial pressure (RAP). However, the association between PV pulsatility and the condition of HF remains unclear.
Hypothesis:
In this study, we aim to evaluate usefulness of PV pulsatility as a prognostic marker as well as a therapeutic indicator for hospitalized acute HF patients.
Methods:
We enrolled 54 patients with acute HF and 17 patients without HF served as controls. PV flow velocity was measured by ultrasonography at admission and discharge phase. PV pulsatility ratio (PVPR) was calculated by dividing minimal velocity by peak velocity. The primary endpoint for prognostic analysis was cardiac death and unexpected re-hospitalization for recurrent HF. The observation period was one year from first hospitalization for HF.
Results:
On admission, PVPR was significantly higher in controls compared to acute HF patients (0.91±0.08 vs. 0.71±0.04, p<0.01).PVPR did not change during the hospitalization in controls (admission 0.91±0.08 vs discharge 0.93±0.06, p=0.31). However, in acute HF patients, PVPR was significantly elevated after the improvement of HF (admission 0.71±0.04 vs discharge 0.82±0.02, p<0.05) due to the increase in minimal velocity (admission 12.6±4.5 cm/s vs. discharge 14.6±4.6 cm/sec, p<0.05), indicating the decrease in RAP. To elucidate the association between PVPR and primary endpoint, the patients were divided into three groups according to the tertile of PVPR at discharge (PVPR-Q1:0.92<PVPR<1, PVPR-Q2: 0.73<PVPR<0.92, PVPR-Q3:PVPR<0.73). Kaplan-Meier analysis found that the patients with higher PV pulsatility at discharge had significantly higher event rate among the groups (Figure).
Conclusions:
PVPR at discharge would reflect the condition of HF. It also can be a novel prognostic marker for hospitalized acute HF patients.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.