Impact of Pulsed Nd:YAG Laser Irradiation on the Growth and Mortality of the Biofilm Forming Marine Bacterium Pseudoalteromonas carrageenovora

The impact of pulsed laser irradiation on the marine biofilm forming bacterium Pseudoalteromonas carrageenovora was investigated in the laboratory by monitoring mortality and the post-irradiation growth pattern. The impact of laser irradiation on bacterial mortality increased with the duration of irradiation. Laser irradiation at 532 nm (0.1 J cm m 2 ) for 15 min resulted in a 53% cell mortality immediately after irradiation. However, the impact after a period of 5 h (delayed impact) was more severe. The growth pattern of irradiated samples showed a prolonged lag phase compared to the reference, due to a reduction in total viable counts (TVC) in the irradiated samples. Nucleic acid staining is suggested to be a promising technique for monitoring laser inflicted bacterial mortality. Thus, the results suggest that laser irradiation could be considered as an alternative technique to reduce the number of biofilm forming bacteria and thereby biofilm formation on hard surfaces.     

Increased high‐latitude photosynthetic carbon gain offset by respiration carbon loss during an anomalous warm winter to spring transition

Arctic and boreal ecosystems play an important role in the global carbon (C) budget, and whether they act as a future net C sink or source depends on climate and environmental change. Here, we used complementary in situ measurements, model simulations, and satellite observations to investigate the net carbon dioxide (CO₂) seasonal cycle and its climatic and environmental controls across Alaska and northwestern Canada during the anomalously warm winter to spring conditions of 2015 and 2016 (relative to 2010–2014). In the warm spring, we found that photosynthesis was enhanced more than respiration, leading to greater CO₂ uptake. However, photosynthetic enhancement from spring warming was partially offset by greater ecosystem respiration during the preceding anomalously warm winter, resulting in nearly neutral effects on the annual net CO₂ balance. Eddy covariance CO₂ flux measurements showed that air temperature has a primary influence on net CO₂ exchange in winter and spring, while soil moisture has a primary control on net CO₂ exchange in the fall. The net CO₂ exchange was generally more moisture limited in the boreal region than in the Arctic tundra. Our analysis indicates complex seasonal interactions of underlying C cycle processes in response to changing climate and hydrology that may not manifest in changes in net annual CO₂ exchange. Therefore, a better understanding of the seasonal response of C cycle processes may provide important insights for predicting future carbon–climate feedbacks and their consequences on atmospheric CO₂ dynamics in the northern high latitudes.     

Survival rate and environmental response of current-year seedlings of the temperate liana Wisteria floribunda across a heterogeneous environment

Journal of Plant Research - Lianas have a huge influence on forest structure and function. However, it is unclear how the surrounding environment affects the establishment of liana seedlings in...     

A novel enzymatic process for glycogen production

Two well-established methods to prepare glycogen are available: (1) extraction from natural resources such as shellfish and animal tissues; (2) synthesis from glucose-1-phosphate using two enzymes, α-glucan phosphorylase (EC 2.4.1.1) and branching enzyme (EC 2.4.1.18). We have developed a novel enzymatic process for glycogen production, in which short-chain amylose is first prepared from starch or dextrin by using isoamylase (EC 3.2.1.68), and then branching enzyme and amylomaltase (EC 2.4.1.25) are added to synthesize glycogen. Our enzymatic process, using isoamylase, branching enzyme and amylomaltase, is currently the most efficient for glycogen production. Furthermore, the molecular weight of glycogen is controllable in a range of 3.0×10⁶ to 3.0×10⁷ by adjusting some parameters of the reaction.     

Myeloperoxidase has Directly-opposed Effects on Nitration Reaction--Study on Myeloperoxidase-deficient Patient and Myeloperoxidase-knockout Mice

Myeloperoxidase (MPO) catalyzes a nitration reaction to form nitrotyrosine in the presence of high nitrite, the metabolite of NO. Human leukocyte was shown to cause phenolic nitration using released MPO as a catalyst in the presence of nitrite. It opposes our previous finding that inhibition of MPO was essential for phenol nitration in human leukocyte study. To clarify the role of MPO, we utilized MPO-deficient human leukocytes and MPO-knockout mice. Even in the absence of exogenously added nitrite, high nitration product was observed in MPO-deficient leukocytes. In liver subjected to ischemia/reperfusion injury, a significantly higher amount of nitrotyrosine was produced in MPO-knockout mice than in normal mice. These results clearly demonstrate that MPO inhibits the accumulation of nitration products in vivo . Further experiments showed that MPO could degrade nitrotyrosine in the presence of glutathione. Thus, MPO-induced degradation of nitration products may cause the underestimation of the nitration product generated in vivo . We conclude that MPO may act predominantly to scavenge nitrotyrosine under physiological nitrite condition, and protect against injurious effect of nitrotyrosine.     

Inhibition of Influenza Virus Replication by Phosphorothioate and Liposomally Endocapsulated Oligonucleotides

Abstract

We have demonstrated that antisense phosphorothioate oligonucleotides (S-ODNs) inhibit influenza virus A replication in MDCK cells. Phosphorothioate and liposomally encapsulated oligonucleotides with two target sites (PB1 and PB2) were synthesized and tested for virus-induced cytopathogenicity effects by a MTT assay using MDCK cells. The liposomally encapsulated S-ODNs complementary to the sites of the PB2-AUG initiation codon showed highly inhibitory effects. On the other hand, the inhibitory effect of the liposomally encapsulated S-ODNs targeted to PB1 was considerably decreased in comparison with the PB2 target sites. The liposomally encapsulated oligonucleotides exhibited higher inhibitory activity than the free oligonucleotides. The activities of the modified oligonucleotides are effectively enhanced by using the liposomal carrier.