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Wastewater produced by milking facilities is harmful to the environment if not properly managed but can be costly to treat. A field demonstration of a constructed, vertical flow, subsurface treatment wetland (also known as a vegetated gravel contactor) in mid-Michigan has had continual success for over five years. However, the wetland's design was not optimized. Data from two lab-scale wetlands that simulated the field installation were collected and analyzed in order to create sizing and design criteria. Nutrients, including phosphorus, organic matter, total nitrogen, ammonia, and nitrate, were monitored as well as pH and chemical oxygen demand. The design and sizing are dependent on the configuration of the milking facility, specifically if the wash water contains significant amounts of manure. Nitrogen levels in the manure-contaminated wash water were three times higher than in the manure-free wash water. Although the manure-free and manure-contaminated wash waters had similar levels of carbon, the manure-contaminated wetland had high nitrogen levels. As a result, the acceptable loading differed between the wetlands: the manure-contaminated wash water loading was determined by nitrogen removal, and the manure-free wash water loading was determined by carbon removal. Phosphorus treatment was adequate, but temporary, as the wetland media lost capacity with time. [ABSTRACT FROM AUTHOR]

An alternative group 2 sigma factor was identified in the nitrogen-fixing, symbiotically competent cyanobacterium Nostoc punctiforme and designated sigH. Transcription of sigH was specifically induced within 1.5 h following exposure of N. punctiforme to its symbiotic plant partner, Anthoceros punctatus. A mutation in sigH resulted in a sixfold-higher initial infection of A. punctatus tissue without a parallel increase in nitrogen-fixing activity.

A Tn5-1063-derived mutant of Nostoc punctiforme strain ATCC 29133 was unable to fix N2 in air although it reduced acetylene in the absence of O2. Mutant strain UCD 307 formed cells morphologically similar to heterocysts, but it failed to synthesize the characteristic heterocyst glycolipids. Sequence analysis around the site of insertion revealed an ORF of 3,159 base pairs, termed hglE. hglE putatively encodes a 115.4-kDa protein containing two domains with conserved amino acid sequences identified with acyl transferase and the chain length factor variation of beta-ketoacyl synthase active sites. These active sites are characteristic of polyketide and fatty acid synthases. The N. punctiforme strain 29133 hglE gene is transcribed only under nitrogen-limiting growth conditions. The hglE gene, or similar sequences, was found in all other heterocyst-forming cyanobacteria surveyed and was absent in unicellular Synechococcus sp. strain PCC 7942. Based on these results, we propose that the synthesis of heterocyst glycolipids follows a pathway characteristic of polyketide synthesis and involves similar large, multienzyme complexes.

Nostocacean cyanobacteria typically produce gliding filaments termed hormogonia at a low frequency as part of their life cycle. We report here that all Nostoc spp. competent in establishing a symbiotic association with the hornwort Anthoceros punctatus formed hormogonial filaments at a high frequency in the presence of A. punctatus. The hormogonia-inducing activity was produced by A. punctatus under nitrogen-limited culture conditions. The hormogonia of the symbiotically competent Nostoc spp. were characterized as motile (gliding) filaments lacking heterocysts and with distinctly smaller cells than those of vegetative filaments; the small cells resulted from a continuation of cell division uncoupled from biomass increase. An essentially complete conversion of vegetative filaments to hormogonia occurred within 12 h of exposure of Nostoc sp. strain 7801 to A. punctatus growth-conditioned medium. Hormogonia formation was accompanied by loss of nitrogen fixation (acetylene reduction) and by decreases in photosynthetic CO(2) fixation and in vivo NH(4) assimilation of 30% and approximately 40%, respectively. The rates of acetylene reduction and CO(2) fixation returned to approximately the control rates within 72 to 96 h after hormogonia induction, as the cultures of Nostoc sp. strain 7801 differentiated heterocysts and reverted to the vegetative growth state. The relationship between hormogonia formation and symbiotic competence is discussed.

A process based on reversed-phase high-performance liquid chromatography (RP-HPLC) has been developed for the purification of biosynthetic human insulin (BHI). The RP-HPLC procedure has been successfully integrated into the multimodal chromatographic production process used to purify kilogram quantities of BHI. Axial compression column technology was used in the scale-up process. The RP-HPLC procedure yields an insulin product having high chemical purity and full biological activity.