Algal growth on organic compounds as nitrogen sources

Two experimental series were run to evaluate the potential of algal development on dissolved organic nitrogen (DON) compounds as the sole source of nitrogen (N) nutrition. Monocultures of several common Lake Kinneret algae (Pediastrum duplex, Synechococcus sp., Microcystis aeruginosa, Aphanizomenon ovalisporum and Cyclotella sp.) were incubated for 3 weeks in the laboratory with different inorganic (NH4⁺, NO3^-) or organic (hypoxanthine, urea, guanine, ornithine, glucosamine, lysine) nitrogen sources. Even though the cultures were not axenic, marked differences were observed in algal growth response. Pediastrum, Cyclotella and Aphanizomenon grew well on most N sources, and cyanobacterial growth and yield were consistently greatest when the urea was the only N source. We also followed algal growth and eventual species dominance in batch samples of GF/F-filtered lake water, supplemented with orthophosphate and different inorganic or organic N compounds and inoculated with concentrated lake phytoplankton. Although no clear impact on phytoplankton growth (as chlorophyll concentration) was observed, in seven out of 11 experiments we could discern changes in the algal species that became dominant in flasks with different organic and inorganic N sources. Our results are consistent with the proposition that components of the DON pool are not only an important potential, direct or indirect N source for phytoplankton, but also that different algal species can exploit these sources with varying capabilities so that different N substrates may selectively stimulate the development of dominant algal species.      

Utilization of organic compounds as the sole source of nitrogen by Thiobacillus thiooxidans

Thiobacillus thiooxidans DSM 504 was shown to grow with adenine, hypoxanthine, xanthine and uric acid as sole sources of nitrogen. Growth with these compounds was observed after lag periods of varying lengths, unless the cells had been previously grown with the same purine base. The disappearance of adenine was accompanied by a temporary accumulation of hypoxanthine in the medium. The utilization of purines was inhibited by ammonia (1 mM). Guanine, pyrimidines and some other organic compounds were not utilized.Non-standard abbreviation U-¹⁴C uniformly labeled by ¹⁴C     

The ability of selected bacterial isolates to utilise components of synthetic metal-working fluids as sole sources of carbon and nitrogen for growth

A total of 24 bacterial isolates able to grow on metal-working fluids were obtained from soil or metal-working fluids (both in-use and heavily contaminated fluids). Pure cultures of the isolates were tested for their ability to degrade a selection of components, including borate esters, phosphate ester, biocide and triethanolamine, typically found in synthetic metal-working fluids. All components, when present at a level equivalent to half that found in an in-use metal-working fluid, supported growth when utilised as the sole source of carbon and/or nitrogen. Each component was degraded by at least 50% by an individual isolate within 120 hours in batch liquid culture.     

The utilization of organic nitrogen compounds as sole nitrogen source by some freshwater phytoplankters

Seven organic compounds containing nitrogen were tested as potential sources of nitrogen for five different species of freshwater algae. The chlorococcal green algae Selenastrum and Ankistrodesmus were the most versatile with regard to nitrogen sources; the diatom Cyclotella also grew well upon some organic nitrogen compounds. The desmid Arthrodesmus grew fast only on urea, while Cryptomonas did not grow well upon any of the organic compounds tested.
More information is needed before the potential importance of organic nitrogen sources for freshwater phytoplankton can be assessed.     

Comparative utilization of inorganic and organic compounds as sole nitrogen sources by the submergent duckweed,Lemna trisulca L.

The capability of the submergentLemna trisulca L. to utilize various inorganic and organic sources of nitrogen was studied using both non-axenic and axenic cultures. When doubling time for frond production was measured, the nitrogen sources in order of effectiveness were urea, aspartic acid, nitrate, glutamic acid, arginine, ammonium and casein hydrolysate. Nitrite supported a relatively rapid growth rate after an initial lag of 7 days. Other parameters of growth such as fresh or dry weight per frond or ohlorophyll content did not oorrelate well with rate of frond production. Casein hydrolysate and urea were found to elicit a morphology different from that seen in cultures containing the other nitrogen sources. These preferences for source of nitrogen were different than those known for the emergent species ofLemnaceae. The unique value ofL. trisulca as a subject for plant physiological research is discussed. This study also provides a possible explanation for the existence of nutritional niches existing in aquatio ecosystems containing several different species ofLemnaceae.     

The use of purine compounds as sole sources of carbon and nitrogen by Klebsiella species

Sixty-one strains of Enterobacteriaceae were tested for purine assimilation, including twenty-five Klebsiella pneumoniae, seventeen K. oxytoca and nineteen others. Only K. pneumoniae and K. oxytoca were able to use guanosine triphosphate, xanthine, hypoxanthine, or uric acid as sole sources of carbon and nitrogen. When guanosine triphosphate was used as sole source of nitrogen and carbon, the lag phase was prolonged. The addition of glucose did not affect the maximum number of viable cells for K. pneumoniae ATCC 29665, but produced an increase for strain K. oxytoca ATCC 13030. In the case of uric acid, ATCC 29665 had a more distinct lag phase of growth than ATCC 13030. Apart from this, they appeared to be very similar. On solid chemically defined GTP medium, some strains of Klebsiella were able to produce a water-soluble brown pigment.     

Urea as sole source of nitrogen for plant growth

Summary Spirodela oligorrhiza grown in sterile culture was able to use urea as sole source of nitrogen but only when the pH of the culture medium was below 4.3. Plants inoculated into urea media at pH 6.4 initially made little growth and became nitrogen-deficient in appearance and composition although they contained about 100 grams of urea per gram fresh weight of tissue. After a period the pH of the medium usually fell below 4.3 and growth commenced. Growth with other compounds, e.g. ammonium, nitrate or allantoin, as sources of nitrogen was not similarly affected by the pH of the culture medium.Urease activity could always be detected in the tissues of Spirodela oligorrhiza growing on urea. Plants with little or no urease activity soon developed significant activity when inoculated into urea media at pH 4.0. When the pH of the medium was higher there was no increase in urease activity and no growth ensued. Plants growing on urea possessed an activity of about 50 milliunits per gram fresh weight of tissue, but if the pH of the medium fell to 3.5 or lower, the activity present rose to 10 times this level.Urease activity also appeared, in the absence of supplied urea, as plants became increasingly nitrogen-deficient.     

Transporters for uptake and allocation of organic nitrogen compounds in plants

Nitrogen is an essential macronutrient for plant growth. Following uptake from the soil or assimilation within the plant, organic nitrogen compounds are transported between organelles, from cell to cell and over long distances in support of plant metabolism and development. These translocation processes require the function of integral membrane transporters. The review summarizes our current understanding of the molecular mechanisms of organic nitrogen transport processes, with a focus on amino acid, ureide and peptide transporters.     

有机碳源和氮源对三角褐指藻生长的影响

研究了8种有机碳源和4种氮源对三角褐指藻(Phaeodactylum tricornutum)生长的影响.结果表明,三角褐指藻具有兼养生长的能力,碳浓度为5mmol/L和50mmol/L时,葡萄糖、果糖、乙酸钠和甘油对其生长有明显的促进作用,乳酸钠和乙醇抑制藻细胞生长,半乳糖和柠檬酸钠对其生长随有机碳浓度而异.甘油、葡萄糖和乙酸钠的适宜浓度范围分别为5 -800mmol/L、100 -400mmol/L和50 -300mmol/L.培养液中分别加入50mmol/L甘油、400mmol/L葡萄糖和150mmol/L乙酸钠,培养第14天,三角褐指藻的最大生物量分别为对照的1.45倍、1.25倍和1.11倍.甘油兼养生长的最优氮源是尿素,适宜浓度范围为0.88-8.8mmol/L.当尿素浓度为4.4mmol/L时,最高生物量可达1.31g/L.     

Dibenzothiophene sulfur can serve as the sole electron acceptor during growth by sulfate-reducing bacteria

Summary Three species of Sulfate-Reducing Bacteria (SRB) were able to grow using dibenzothiophene (DBT) as their sole source of sulfur and sole electron acceptor. Desulfotomaculum orientis and Desulfovibrio desulfuricans were grown at 30°C while Thermodesulfobacterium commune was grown at 60°C, in media containing lactate and citrate. Hydrogen sulfide was the product of dissimilatory sulfur reduction.Research supported by the Office of Oil and Gas Processing of Fossil Energy, U.S. Department of Energy under contract DE-AC05-84OR21400 with Martin Marietta Energy Systems Inc.     

Detection, with the dye phloxine B, of yeast mutants unable to utilize nitrogenous substances as the sole nitrogen source.

Yeast mutants unable to degrade certain nitrogen compounds produce characteristic small red colonies on an agar medium containing the red dye phloxine B, galactose, the test nitrogen compound, and a small amount of ammonium chloride.     

Application of the profiles of amino acid utilization as the sole carbon and nitrogen sources for pseudomonad taxonomy

Profiles of utilization of 20 amino acids were determined for 218 strains of 10 Pseudomonas species (P. aeruginosa, P. putida, P. fluorescens, P. stutzeri, P. alcaligenes, P. pseudoalcaligenes, P. luteola, P. oryzihabitans, P. mendocina, and P. chlororaphis), including the type strains of these species. Amino acid utilization was determined on minimal salt agar with an amino acid as the sole source of nitrogen and carbon. All the investigated pseudomonad species had species-specific profiles of amino acid utilization. For the type strains of all species, Jaccard’s coefficients of community were different (Sj = 0.31–0.82), in accordance with the interspecies differences. The similarity between the intraspecies variants of the profiles and that of the type strain was high; for 98% of P. aeruginosa strains, Sj = 0.85−1.0; for 100% of P. putida, P. stutzeri, and P. alcaligenes strains, Sj was 0.87–1.0, 0.90, and 0.86–1.0, respectively. Only for P. fluorescens and P. pseudoalcaligenes were low Sj of the intraspecies profiles revealed, in accordance with the known phenotypic heterogeneity of these species. These results agree with the known pseudomonad classification, and the method is therefore valid for identification of known species and for determination of the new members of the genus Pseudomonas.     

Amino adids as nitrogen sources for the growth of rice callus tissue

Availability of amino acids for the growth of rice callus tissuewas examined by supplying various kinds of amino acids to thetissue separately or in combination. When an amino acid wassupplied alone as the sole source of nitrogen, only the followingfive amino acids were found to favour the growth of callus tissue;arginine, alanine, asparagine, glutamine and proline. In combinationwith other acids, both AHCH and CMAA were very effective instimulating the growth of tissue, but EHCH was inhibitory. Whenmethionine or arginine was excluded from the CMAA medium, callusgrowth on the medium was reduced significantly. The effect producedby omitting methionine suggested that some amino acid interactionwas involved in this instance. (Received February 19, 1970; )     

干旱胁迫下几种荒漠植物抗氧化能力的比较研究

对3种荒漠植物沙拐枣、梭梭和沙枣在干旱胁迫下的抗氧化能力进行了比较研究。结果表明,3种荒漠植物长期处于干旱生境下,都受到不同程度的膜脂过氧化,其中,沙枣的膜脂过氧化程度大于梭梭和沙拐枣。在1d的变化中,随着水势的下降,上午10：00前3种植物体内MDA含量都表现为上升趋势,此后梭梭和沙拐枣体内MDA含量表现为持续下降,到下午18：00达到最低,说明尽管水分胁迫在加强,它们却表现出极强的抗氧化胁迫能力;而沙枣体内MDA含量在下午18：00又开始上升,表明沙枣表现出一定的调节能力,但其能力有限,低于梭梭和沙拐枣。3种植物对干旱胁迫的应激方式不同;沙拐枣体内的SOD活性和ASA含量明显高于梭梭和沙枣,这与其体内相对较低的O2含量具有很好的一致性;对于植物体内H2O2的清除,抗氧化酶系统对沙拐枣体内的H2O2的清除起了一定的作用,但不是主要的,抗氧化剂GSH起主要作用,而梭梭体内南抗氧化酶系统中的CAT起主要作用,抗氧化剂起辅助作用;沙枣体内的AsA-POD起主要作用,其它的抗氧化酶和氧化剂起辅助作用。同时,植物体内还保持管各种酶的平衡。     

Investigation of mercaptans,organic sulfides,and inorganic sulfur compounds as sulfur sources for the growth of methanogenic bacteria

A variety of compounds were investigated for use as sulfur sources for the growth of methanogenic bacteria.Methanococcus (Mc.) deltae, Mc. maripaludis, Methanobacterium (Mb.) speciesGC-2B, GC-3B, andMMY, Methanobrevibacter (Mbr.) ruminantium, andMethanosarcina (Ms.) barkeri strain 227 grew well with sulfide, S^o, thiosulfate, or cysteine as sole sulfur source.Mbr. ruminatium was able to grow on SO ₄ ⁼ or SO ₃ ⁼ , andMs. barkeri strain 227 was able to grow on SO ₃ ⁼ , but not on SO ₄ ⁼ as a sole sulfur source.Mc. jannaschii grew with sulfide, S^o, thiosulfate or SO ₃ ⁼ , but not on cysteine or SO ₄ ⁼ as sole surface source.Mc. thermolithotrophicus, Mc. jannaschii, Mc. deltae, andMb. thermoautotrophicum strains Marburg and H were able to grow with methanethiol, ethanethiol,n-propanethiol,n-butanethiol, methyl sulfide, dimethyl sulfoxide, ethyl sulfide, or CS₂ as a sulfur source, when very low levels (20–30 M) of sulfide were present; no growth occurred on 5–100 M sulfide alone. Methanethiol, ethanethiol, and methyl sulfide-using cultures produced sulfide during growth.     

Abilities of organic acids to support growth and anthocyanin accumulation by suspension cultures of wild carrot cells using ammonium as the sole nitrogen source

Summary Fifteen organic acids were examined for their abilities to support the growth and anthocyanin accumulation by suspension cultures of wild carrot (Daucus carota L.) using ammonium as the sole nitrogen source. Glutarate, adipate, pimelate, azelate, cinnamate, and phthalate were toxic to the culture. They prevented growth and anthocyanin accumulation at 5 mM or less in media that were otherwise adequate for growth. Succinate, fumarate, malate, α-ketoglutarate, glutamate, maleate, malonate, tartarate, and citrate all supported growth and anthocyanin accumulation but in varying amounts. The growth achieved in medium containing 20 mM acid was higher at an initial pH of 5.5 than at an initial pH of 4.5. The growth achieved was dependent on the organic acid used, its concentration, and the initial pH of the medium. When growth occurred the final pH was higher than the initial pH with most of the acids. Anthocyanin accumulation was greatest with succinate at 14 to 20 mM at an initial pH of 4.2 or 4.3 and declined when the initial pH was above 4.3. These studies were supported by grants from General Foods Corporation and the W. Alton Jones Foundation.