Experimental effects of elevated salinity on three benthic invertebrates in Pyramid Lake,Nevada

Salinity of Pyramid Lake increased from 3.7 to 5.5 between 1933 and 1980. Concern over future reductions in overall species richness prompted experiments to assess responses of dominant lake organisms to elevated salinity. Salinity tolerances of three important benthic invertebrates, Hyalella aztecta, Chironomus utahensis, and Heterocypris sp., were tested in controlled laboratory bioassays and also in a semi-natural environment consisting of large (47 m³) mesocosms.Densities of H. azteca in mesocosms were significantly lower at salinities of 8.0 and 11.0 compared with 5.6 controls in year one, but not in 8.5 salinity mesocosms in year two. The 96-h LC₅₀ for H. azteca was high at 19.5. Short-term mortalities of C. utahensis were 100% at salinities of 13.3 and greater. Fifty-seven percent fewer larvae matured from third to fourth instar at 8.9 than at 5.5 salinity in 17 day subacute bioassays. Furthermore, larval chironomid densities and emergence of adults from mesocosms were significantly reduced at salinities of 8.0 and higher compared with controls. Mortality of Heterocypris sp. was 50% at a salinity of 18.6 in laboratory bioassays and populations in mesocosms ranged between 40 and 100% lower at salinities of 8.0 and 11.0 than in controls.Multiple generation mesocosm experiments indicated all three invertebrates were more sensitive to elevated salinity than results of short-term bioassays. Our studies suggest populations of these invertebrates may be reduced from present levels if Pyramid Lake's salinity were to double, although none are expected to be extirpated. Food habit shifts and reduced production of lake fishes are likely consequences of salinity-induced disruption in the benthic invertebrate forage base.     

Ac transposition in transgenic tomato plants

Summary As an initial step towards developing a transposon mutagenesis system in tomato, the maize transposable element Ac was transformed into tomato plants via Agrobacterium tumefaciens. Southern analysis of leaf tissue indicated that in nine out of eleven transgenic plants, Ac excised from the T-DNA and reintegrated into new chromosomal locations. The comparison of Ac banding pattern in different leaves of the same primary transformant provided evidnece for transposition during later stages of transgenic plant development. There was no evidence of Ds mobilization in tomato transformants.     

Patents and patent office resources in biotechnology

Patents play an increasingly important role in the dissemination of information in many fast moving fields such as biotechnology and semiconductors. Quite a few new developments are introduced as patents, and only later, if at all, do they find their way into the scientific literature. In spite of this, patents lack wide acceptance as a source of information among scientists in academia and, to a lesser degree, industry. Patents share many similarities with scientific papers. They both are organized in a similar way and are carefully reviewed by experts in the field. Both can be effective and timely sources of information. Patents can be accessed through data bases, library collections, the "Official Gazette of the Patent and Trademark Office," or directly in the Patent and Trademark Office. This article is designed to serve as a guide to the type of information which can be found in patents, and alternatives for obtaining this information.     

Rat epididymal alpha-D-mannosidase: purification, carbohydrate composition, substrate specificity, and antibody production

Two alpha-D-mannosidases have previously been identified in rat epididymis. This communication reports the purification and characterization of the "acid" alpha-D-mannosidase. The enzyme was purified over 1000-fold to near homogeneity by acetone and (NH4)2SO4 precipitation followed by ion-exchange and hydroxylapatite chromatography. The molecular weight of the enzyme was estimated to be 220,000 by gel filtration. Polyacrylamide gel electrophoresis of the native enzyme under two conditions of buffer and pH showed a single band when stained for protein while electrophoresis under denaturing conditions resulted in bands of apparent Mr 60,000 and 31,000. The enzyme is a glycoprotein containing about 5.6% hexose. In addition to mannose (3.1%) and glucosamine (2.0%), the enzyme also contained small amounts of glucose, fucose, and galactose. Chemical analysis indicated the absence of sialic acid. The substrate specificity of the purified enzyme was investigated using linear and branched mannose-containing oligosaccharides. The enzyme cleaved linear oligosaccharides [Man(alpha 1-2)Man(alpha 1-2)Man(alpha 1-3)Man(beta 1-4)GlcNAc and Man(alpha 1-2)Man(alpha 1-3)Man(beta 1-4)GlcNAc] very efficiently. However, little or no activity was observed toward high mannose oligosaccharides (Man9GlcNAc through Man5GlcNAc) or the branched trimannosyl derivative Man3GlcNAc. This specificity is very similar to that observed with rat kidney lysosomal alpha-D-mannosidase. Additional evidence that the epididymal enzyme is essentially a lysosomal alpha-D-mannosidase is the fact that polyclonal antibody prepared against the purified epididymal enzyme cross-reacted with lysosomal alpha-D-mannosidase from several rat tissues and with acidic alpha-D-mannosidase of a human cell line, results suggesting that the antibody will be useful in studying the biosynthesis and turnover of lysosomal alpha-D-mannosidases in at least two species.     

A murine IgM monoclonal antibody binds an antigenic determinant in outer surface protein A, an immunodominant basic protein of the Lyme disease spirochete

A hybridoma cell line formed by the fusion of the P3x63-Ag8.653 myeloma cell line with splenocytes from BALB/c mice immunized with Borrelia burgdorferi produced an IgM monoclonal antibody (mAb-11G1) with kappa-light chains which detected an antigenic determinant in a major spirochetal protein of m.w. approximately 31,000, also known as outer surface protein A (OSP-A). Apparent saturation was reached in approximately 35 min with 34 ng of mAb-11G1 binding to 5 X 10(7) spirochetes giving an estimated 4.8 X 10(2) IgM molecules per spirochete and thus a minimum of 480 binding sites per organism. Enzymatic digestion studies suggest that the antigenic determinant to mAb-11G1 is contained within the peptide chain of OSP-A as binding could be eliminated by treatment of the spirochetes with proteinase K, Pronase and pepsin (100 to 200 micrograms/ml of enzyme) but not by trypsin or bromelain treatment. Periodate oxidation as well as mixed and endoglycosidase treatment of the spirochetes did not alter the binding of mAb-11G1. Two-dimensional gel electrophoresis of whole spirochetal cell lysates disclosed that OSP-A is a heterogeneously charged basic protein with an apparent isoelectric point range from 8.5 to 9.0. Amino acid analysis of OSP-A showed a 10% lysine component which could provide the basic nature to the protein. OSP-A with the intact antigenic determinant for mAb-11G1 can be found in the urine of hamsters experimentally infected with B. burgdorferi.     

Catalase-like crystals in parathyroid gland cells of Rana temporaria L.

Summary Crystalline inclusions in parathyroid gland cell nuclei of Rana temporaria were studied by electron microscopy using a specimen tilting stage. Images were analysed by optical diffraction. Results were compared with X-ray and electron microscopic data of trigonal bovine liver catalase to which a striking resemblance of the inclusions was found.We are grateful to Professor R. Mosebach (Giessen) for discussions, to the Deutsche Forschungsgemeinschaft for a grant (La 229/4) and instruments and to Messrs. Spindler & Hoyer, Göttingen and Messrs. Rank Precision Instruments, Nürnberg for putting apparatus at our disposal and performing diffraction photographs.     

Location of phosphorylase kinase (Phk) in the mouse X chromosome

The phosphorylase kinase deficiency (Phk) locus has been located in the mouse X chromosome, the order of genes being centromere-Bn-Phk-Ta-jp. Since the Phk locus of the mouse may be identical to the locus responsible for the X-linked phosphorylase kinase deficiency trait of man, and there may be a high degree of gene-order homology in the X chromosome of all mammals, the location of Phk in the mouse reported here may aid in locating the phosphorylase kinase gene on the X chromosome of man.This research was supported by grants AM 13359 (to F.H.) and AM 14461 (to D.L.C.) from the National Institute of Arthritis and Metabolic Diseases, and by an allocation (to E.M.E.) from NIH General Research Support Grant RR-05545 from the Division of Research Resources to The Jackson Laboratory. F.H. is a recipient of a Research Career Development Award (AM 46 421) of the National Institute of Arthritis and Metabolic Diseases.