Potential use of the astaxanthin-producing microalga, <Emphasis Type="Italic">Monoraphidium</Emphasis> sp. GK12, as a functional aquafeed for prawns

We determined the nutritional profile of Monoraphidium sp. GK12, a newly isolated astaxanthin (AXA)-producing microalga, and investigated its potential use as a functional aquafeed by evaluating its effect on prawn pigmentation. GK12 contained high levels of pantothenic acid. The β-carotene content of GK12 was higher than that of Haematococcus, a well-studied AXA producer, and was similar to that of Spirulina. GK12 also had a high content of unsaturated fatty acids, of which linolenic acid (C18:3 n−3) was the most plentiful. A GK12-containing feed resulted in significant pigmentation of the prawns, comparable to that of prawns fed on synthetic AXA or Haematococcus. A GK12-containing feed also increased the survival rate of the prawns. Therefore, in addition to improving cultivation methods for Haematococcus, further research is needed into the use of GK12 as an alternative AXA source and as an ingredient of functional aquafeed for farmed fish.     

Analysis of the hemagglutinin glycoprotein from mutants of vaccinia virus that accumulates on the nuclear envelope

We isolated mutants whose vaccinia hemagglutinin (HA) accumulates on nuclear envelopes and the rough endoplasmic reticulum. Mutant HA must be blocked at a pre-Golgi step because it has high-mannose-type carbohydrates but no fucose. Neither N- nor O-glycosidically linked carbohydrates are involved in the transport defect of the mutant HA, because tunicamycin, an inhibitor of N-type glycosylation, has no effect, and O-type glycosylation takes place in the Golgi organelle. The unglycosylated form of the mutant HA synthesized in the presence of tunicamycin is 3000 daltons larger than the wild type. This higher molecular weight is related to the transport defect. HAs translated in vitro also show this difference, evidence that it reflects mutation in the HA structural gene. Portions of HAs that project into the cytoplasm seem to account for this weight difference. Thus the cytoplasmic tail of glycoprotein has an important function in transport out of the rough endoplasmic reticulum.