Standardized evaluation and rating of biofilters: II. Manufacturer''s and user''s perspective

As manufacturers of biofilters we feel that it is important that our customers have a standardized set of criteria that can be used to compare the many different commercially available biofilters on the market today. The purpose of this paper is to show how a variety of manufacturers size their own filters, establish commonalities between the methods and suggest, to the engineering community, the needs of the industry that are required to develop a uniform sizing criteria. Similarities in sizing methodologies include standard information supplied by the consumer (system volume, feed rate, etc.) as well as those estimated by the manufacturer (TAN production, and hydraulic requirements). Differences in sizing methodology include the use of in situ nitrification and system flushing. From the various examples of biofilter sizing, it is clear that manufacturers use a sizing methodology based on either an areal or volumetric TAN conversion rate (ATR or VTR). As manufacturers, we should be able to publish ATR or VTR for each of three trophic levels (oligotrophic, mesotrophic and eutrophic) with appropriate correction factors for water temperature and salinity. A standardized labeling system that would allow system designers to accurately and rapidly determine which biofilter(s) meet their needs is proposed. We leave it to the engineering community to devise a standardized scheme by which VTR values could be determined to facilitate this comparison.     

Infection of tilapia, Oreochromis mossambicus (Trewavas), by a marine monogenean, Neobenedenia melleni (MacCallum, 1927) Yamaguti, 1963 in Kaneohe Bay, Hawaii, USA, and its treatment

Abstract A disease of saltwater, cage-cultured tilapia, Oreochromis mossambicus (Trewavas), caused by the marine monogenean, Neobenedenia melleni (MacCallum, 1927) Yamaguti, 1963, is described. Up to 400 parasites were found attached to the body surface of individual fish. Heavily infected fish showed hyperirritability, heavy mucus secretion and discoloration. Pathology was most marked on the eye, with corneal opacity initially, followed by buphthalmos, corneal ulceration and rupture of the eye with subsequent degeneration of internal structure. The infection was successfully treated using 2 min freshwater dips.     

Seeking a niche: putative contributions of the hfq and bacA gene products to the successful adaptation of the brucellae to their intracellular home

Long-term residence of the brucellae in the phagosomal compartment of host macrophages is essential to their ability to produce disease in both natural and experimental hosts. Correspondingly, the Brucella spp. appear to be well adapted to resist the multiple environmental stresses they encounter in their intracellular home. This brief review will focus on the contributions of the hfq and bacA gene products to this adaptation. Studies with Brucella hfq mutants suggest that stationary phase physiology is critical for successful long-term residence in host macrophages. Analysis of Brucella bacA mutants, on the other hand, reveal very striking parallels between the strategies employed by the rhizobia to establish and maintain protracted intracellular residence in their plant host and those used by the brucellae during their long-term survival in the phagosomal compartment of host macrophages.     

Combination of a Corticai Allograft With a Cancellous Autograft in the Canine Tibia

This study was undertaken to determine what difference, if any, occurred when autogenous cancellous bone was placed in the medullary canal of a fresh, 4-cm cortical allograft compared to a fresh cortical allograft alone. Twelve mature dogs were used. A tubular cortical graft was placed in the midshaft of both tibias. The right tibia received the combination graft while the left tibia received a fresh cortical allograft only. Study periods ranged from one week to 17 weeks. The progress of the grafts was assessed by technetium-99m radionuclide bone scans, radiographs, gross and histological examination, and tetracycline labeling. Results indicate that autogenous cancellous bone placed in the medullary canal of a fresh cortical allograft was beneficial to the ingrowth of new blood vessels and incorporation of the cortical graft.     

Diversity of indigenous Bradyrhizobium japonicum in North Carolina soils

Summary The diversity of Bradyrhizobium japonicum in agricultural fields has not been well characterized. Therefore a study was conducted to determine the serotypic diversity of B. japonicum both within and among six fields in the Coastal Plain and Piedmont of North Carolina where soybeans [Glycine max (L.) Merr.] are grown. Nodule samples were collected from non-inoculated standing soybean crops. Both nodules and isolates were typed by the enzyme-linked immunosorbent assay (ELISA) technique. Serotypes and their proportions varied both within and among locations. Common serotypes in order of abundance across all sites were 76, M1 (multiple reaction beyween 31 and 94), 94, 24, and 122, and together accounted for over 66% of the typable reactions. No cultivar effect on serotype distribution was observed. Unknown types ranged from 4 to 24%. Based on the total number of serotypes identified and the Shannon diversity index (H), the mean population diversity was 0.76 for the Piedmont sites and 0.91 for the Coastal Plain sites.Paper no. 12315 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, NC 27695-7643. The use of trade names in this publication does not imply endorsement by the North Carolina Agricultural Research Service of the products named or criticism of similar ones not mentioned     

Nodulation competition among Bradyrhizobium japonicum strains as influenced by rhizosphere bacteria and iron availability

Summary Bacteria isolated from the root zones of field-grown soybean plants [Glycine max (L.) Merr.] were examined in a series of glasshouse experiments for an ability to affect nodulation competition among three strains of Bradyrhizobium japonicum (USDA 31, USDA 110, and USDA 123). Inocula applied at planting contained competing strains of B. japonicum with or without one of eleven isolates of rhizosphere bacteria. Tap-root nodules were harvested 28 days after planting, and nodule occupancies were determined for the bradyrhizobia strains originally applied. Under conditions of low iron availability, five isolates (four Pseudomonas spp. plus one Serratia sp.) caused significant changes in nodule occupancy relative to the corresponding control which was not inoculated with rhizosphere bacteria. During subsequent glasshouse experiments designed to verify and further characterize these effects, three fluorescent Pseudomonas spp. consistently altered nodulation competition among certain combinations of bradyrhizobia strains when the rooting medium did not contain added iron. This alteration typically reflected enhanced nodulation by USDA 110. Two of these isolates produced similar, although less pronounced, effects when ferric hydroxide was added to the rooting medium. The results suggest that certain rhizosphere bacteria, particularly fluorescent Pseudomonas spp., can affect nodulation competition among strains of R. japonicum. An additional implication is that iron availability may be an important factor modifying interactions involving the soybean plant, B. japonicum, and associated microorganisms in the host rhizosphere.Paper No. 10648 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, NC 27695-7601, USA     

Modelling riverine habitat for robust redhorse: assessment for reintroduction of an imperilled species

A critical component of a species reintroduction is assessment of contemporary habitat suitability. The robust redhorse, Moxostoma robustum (Cope), is an imperilled catostomid that occupies a restricted range in the south‐eastern USA. A remnant population persists downstream of Blewett Falls Dam, the terminal dam in the Pee Dee River, North Carolina. Reintroduction upstream of Blewett Falls Dam may promote long‐term survival of this population. Tillery Dam is the next hydroelectric facility upstream, which includes a 30 rkm lotic reach. Habitat suitability indices developed in the Pee Dee River were applied to model suitable habitat for proposed minimum flows downstream of Tillery Dam. Modelling results indicate that the Tillery reach provides suitable robust redhorse habitat, with spawning habitat more abundant than non‐spawning habitat. Sensitivity analyses suggested that suitable water depth and substrate were limiting physical habitat variables. These results can inform decisions on flow regulation and guide planning for reintroduction of the robust redhorse and other species.     

Large Experimental Fistula of the Right Dorsal Colon in Horses

Studies in horses with experimental gastrointestinal fistulas may lead to rapid advancements in equine nutrition, as well as prevention and treatment of diseases such as colic and laminitis. The aim of this study was to devise a technique and a cannula to create a large fistula in the right dorsal colon (RDC). A total of 13 horses with normal gastrointestinal tract were used. After the administration of sedatives and local anesthetics, a segment of the right 16th rib was removed, a circular defect was created in the muscular wall, and the RDC was sutured to the muscular wall. The subcutaneous tissue and skin were closed over the attached RDC in eight horses (closed technique), or removed to expose the serosa of the colon sutured to the abdominal wall in five horses (open technique). A full thickness circular incision was made 2 to 6 weeks later to create a fistula. A cannula (diameter, 5 cm) made of natural rubber or silicon was inserted in the fistula. The open surgical technique was easier to perform and resulted in fewer complications. The cannula made of silicon resulted in less pruritus. One horse had a large colon torsion around the colopexy before fistula creation. One of the 12 fistulated horses had a large colon displacement 43 days after cannula insertion. These observations suggest that pexis of the RDC may predispose the horse to large colon displacement or volvulus. The open technique for the colopexy and the cannula made of silicon can be used for creation of a RDC fistula.