scholarly journals Alternative pathways of spirilloxanthin biosynthesis in Rhodospirillum rubrum

1970 ◽  
Vol 116 (1) ◽  
pp. 101-110 ◽  
Author(s):  
B. H. Davies
Keyword(s):  
Photosynthetic Bacteria ◽  
Rhodospirillum Rubrum ◽  
Carotenoid Biosynthesis ◽  
Alternative Pathways ◽  
Alternative Routes ◽  
Novel Structures

Detailed studies of the properties of carotenoids isolated from diphenylamine-inhibited cultures of Rhodospirillum rubrum have revealed a number of novel structures that indicate new features of carotenoid biosynthesis in the photosynthetic bacteria. Both neurosporene and 7,8,11,12-tetrahydrolycopene undergo hydration, methylation and dehydrogenation to yield spheroidene and 11′,12′-dihydrospheroidene respectively; all the intermediates in these pathways have been identified. These pathways represent alternative routes of anhydrorhodovibrin and spirilloxanthin biosynthesis.

scholarly journals Carotenoid Biosynthesis in Photosynthetic Bacteria

1989 ◽  
Vol 264 (22) ◽  
pp. 13109-13113
Author(s):  
G E Bartley ◽  
P A Scolnik
Keyword(s):  
Photosynthetic Bacteria ◽  
Carotenoid Biosynthesis

scholarly journals Math and science outcomes for students of teachers from standard and alternative pathways in Texas

2020 ◽  
Vol 28 ◽  
pp. 27
Author(s):  
Michael Marder ◽  
Bernard David ◽  
Caitlin Hamrock
Keyword(s):  
Student Performance ◽  
Science Teachers ◽  
Algebra I ◽  
High Stakes ◽  
Alternative Pathways ◽  
Biology Students ◽  
University Preparation ◽  
Alternative Routes ◽  
Almost All ◽  
High Stakes Exams

Texas provides a unique opportunity to examine teachers without standard university preparation, for it prepares more teachers through alternative pathways than any other state. We find two advantages for mathematics and science teachers prepared in the standard way. First, since 2008 they have been staying in the classroom longer than those who pursued alternative routes. Second, we analyze student performance on Algebra 1 and Biology exams over the period 2012-2018. Algebra I students with experienced teachers from standard programs gain .03 to .05 in standard deviation units compared to students whose teachers were alternatively prepared. For Biology students there are fewer statistically significant differences, although when differences exist they almost all favor standard programs. These effects are difficult to measure in part because teachers are not assigned to teach courses with high-stakes exams at random. Nevertheless, we find strong evidence in Algebra I that students learn more when their teachers have standard preparation. In Biology there is also evidence but less compelling. Thus, we recommend that all states bolster traditional university-based teacher certification, that Texas not take drastic action to curtail alternative certification, and that other states not allow it to grow too quickly.

scholarly journals Changes in the acyl lipid composition of photosynthetic bacteria grown under photosynthetic and non-photosynthetic conditions

1979 ◽  
Vol 181 (2) ◽  
pp. 339-345 ◽  
Author(s):  
Nicholas J. Russell ◽  
John L. Harwood
Keyword(s):  
Fatty Acids ◽  
Photosynthetic Bacteria ◽  
Rhodospirillum Rubrum ◽  
Relative Proportion ◽  
Photosynthetic Apparatus ◽  
Growth Conditions ◽  
Rhodopseudomonas Capsulata ◽  
Rhodopseudomonas Sphaeroides ◽  
Acyl Lipids ◽  
And Function

The acyl lipids and their constituent fatty acids were studied in the photosynthetic bacteria Rhodospirillum rubrum, Rhodopseudomonas capsulata and Rhodopseudomonas sphaeroides, which were grown under photosynthetic and non-photosynthetic conditions. The major lipids were found to be phosphatidylethanolamine, phosphatidylglycerol and cardiolipin in each bacterium. The two Rhodopseudomonas species also contained significant quantities of phosphatidylcholine. Other acyl lipids accounted for less than 10% of the total. On changing growth conditions from non-photosynthetic to photosynthetic a large increase in the relative proportion of phosphatidylglycerol was seen at the expense of phosphatidyl-ethanolamine. In Rhodospirillum rubrum the fatty acids of the major phospholipids showed an increase in the proportion of palmitate and stearate and a decrease in palmitoleate and vaccenate on changing growth conditions to photosynthetic. In contrast, the exceptionally high levels (>80%) of vaccenate in individual phospholipids of Rhodopseudomonas capsulata and Rhodopseudomonas sphaeroides were unaffected by changing growth conditions to photosynthetic. Analysis of the lipids of chromatophores, isolated from the three bacteria, showed that these preparations were enriched in phosphatidylglycerol. The large increase in this phospholipid, seen during growth under photosynthetic conditions, appeared, therefore, to be due to a proliferation of chromatophore membranes. Possible roles for acyl lipids in the formation and function of the photosynthetic apparatus of bacteria are discussed.

Carotenoid Biosynthesis in Rhodospirillum rubrum: Effect of Pteridine Inhibitor

Science ◽  
1967 ◽  
Vol 158 (3803) ◽  
pp. 922-924 ◽  
Author(s):  
N. A. Nugent ◽  
R. C. Fuller
Keyword(s):  
Rhodospirillum Rubrum ◽  
Carotenoid Biosynthesis

Isolation and Identification of Photosynthetic Bacteria and their Hydrogen Production Characterization

2012 ◽  
Vol 512-515 ◽  
pp. 527-533
Author(s):  
Yan Yan Zhu ◽  
Quan Guo Zhang ◽  
Bin Xu Han ◽  
Yan Yan Jing
Keyword(s):  
Hydrogen Production ◽  
Photosynthetic Bacteria ◽  
Culture Medium ◽  
Gene Sequence ◽  
Rhodospirillum Rubrum ◽  
Rhodobacter Capsulatus ◽  
Solid Medium ◽  
Production Capacity ◽  
Sequence Information ◽  
Isolation And Identification

Using special culture medium, dominant photosynthetic bacterias were enriched from sewage silt and paddy fields with plentiful light and organic compounds. Five strains of photosynthetic bacteria capable of producing hydrogen were purified and isolated by gradual dilution and double—deck solid medium. The analysis of the gene sequence information of 1 6SrDNA was carried out, and the five strains were identified as Rhodospirillum rubrum,R.capsulata, R.pulastris, Rhodobacter capsulatus, Rhodobacter capsulatus . Moreover, it was found that with Optimized medium formula, hydrogen production can be achieved 204h, the maximum hydrogen production capacity of 3.41L, the maximum hydrogen production rate was 44.17ml / (L • h),the highest hydrogen content of 46.73%.

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