Elisa determination of IAA using antibodies against ring-linked IAA

An enzyme-linked immunosorbent assay (ELISA) for indole-3-acetic acid (IAA) is described which uses antibodies raised against IAA conjugated to carrier protein on the indolic ring of IAA. As little as 0.5 pmol of IAA is detectable with the ELISA. There is no significant cross-reactivity with amide conjugates of IAA and samples do not need methylation, in contrast to an ELISA using antibodies raised against carboxyl-linked IAA. Affinity chromatography on IAA-agarose was used to purify antibody preparations. Measurements of IAA levels in crown gall tumour tissue lines were made using the assay.     

Nitrogen Fixation in Wild Legumes

Isolations of the rhizobia from nodules of field plants of Ulexeuropaeus and Medicago lupulina have been examined for effectivenessin fixation of nitrogen by inoculating them into host plantsgrowing in a medium free of combined nitrogen. The results indicatethat vigorous fixation may be presumed to occur in associationwith field plants of the Ulex species, but that fixation inMedicago is probably decreased by the presence of ineffectiverhizobia in some nodules. The general importance of fixationin wild legumes is discussed, and it is pointed out that dueattention must be paid to non-legume genera with root nodules.These genera are locally abundant, and in former periods werestill more prominent in some regions of the world.     

Transitory pulse-like treatment with IAA solution more effectively induces xylogenesis in callus culture than permanent presence of the auxin

Differentiation of Acerpseudoplatanus L. cells into tracheary elements (TE) and an increase in the number of TE inHaplopappus gracilis (Nutt.) A. Gray calli were observed after pulse-treatment of the cultures grown in glass tubes with indole-3-acetic acid (IAA) solutions. The effect was enhanced if the treatment was repeated in three subsequent days. The manner of IAA application which caused a wave-like pattern of IAA flow through the callus culture appeared to be more important than the IAA concentration. Induction of differentiation of A.pseudoplatanus cells and an increase in the number of TE inH. gracilis callus did not occur when the calli were grown on agar media supplemented with increased concentrations of IAA.     

Comparative root anatomy of papilionoid Legumes

The aims of the present study were (i) to compare the anatomical structures of roots from legume species belonging to the tribes Aeschynomeneae, Fabeae (syn. Vicieae), and Trifolieae (Papilionoideae); (ii) to characterize those developmental stages of roots that are most useful for comparative studies; (iii) to characterize root developmental patterns during their growth from primary to adult structures; and (iv) to identify developmental patterns that are typical for particular tribes within this plant group. To this end, serial transverse cuts of the main roots of 20 species belonging to the above-mentioned tribes were made from the root tip to the root collar. Vessel density, vessel diameter, secondary cortex area, and xylem area were quantified using appropriate software. Based on root ontogeny, four stages giving evidence for important developmental events were chosen based on which a comparison of the species-specific structures became possible. The first stage corresponds to the primary structure of a root. The second stage corresponds to the onset of cambium and phellogen division, when their first division products become differentiated. The third and fourth stages correspond to adult roots with a well-developed secondary structure. These developmental stages that allowed between-species comparison turned out to be useful characterising those patterns that best typify a particular tribe within the subfamily. Vessel density, vessel diameter, and the xylem transverse area were found to differ significantly between the tribes examined. Some of the analyzed morphological variables had a tribe-specific consistency, so that, together with other characteristics, they should be included in approaches to clarify systematic problems in the legume family.     

Evidence That IAA Conjugates Are Slow-Release Sources of Free IAA in Plant Tissues

Evidence that indoleacetic acid (IAA) conjugates are metabolized via enzyme-catalyzed hydrolysis to free IAA and that their biological activities are related to the rates at which they are hydrolyzed by the tissue is presented. These conclusions are based on the following observations. Slow but continuous decarboxylation of the IAA moiety of IAA-l-alanine and IAA-glycine occurs when these conjugates are applied to pea (Pisum sativum L. cv. Alaska) stem segments. Inasmuch as IAA conjugates are protected from peroxidase-catalyzed oxidative decarboxylation, the conjugates are probably hydrolyzed and the freed IAA then further metabolized. Free IAA and IAA-l-alanine are converted, by pea stem tissue, into the same metabolites. The metabolism is enzymic, since conjugates of IAA with the d-isomers of the amino acids are inactive. Ethylene production induced by IAA-l-alanine and by IAA-glycine is correlated with their hydrolysis, as indicated by their decarboxylation and with the appearance or nonappearance of IAA metabolites in the tissues.     

Biochemical Studies on Indian Wild Legumes

Chemical screening of some profusely growing wild leguminous seeds of Acacia, Albizzia and Leucaena species, for their nutritional constituents suggested the possibility of their inclusion in animal nutrition. However, since the whole seeds proved to be unpalatable as well as toxic in some cases, it was thought of utility to employ their isolated proteins instead. Accordingly, with a view to explore newer and effective sources of dietary proteins, simple and effective solubility method was employed for their extraction, precipitation, fractionation and isolation from the undesirable wild seed constituents to obtain the protein fractions in the pure form which could be incorporated in animal nutrition. Distribution of total nitrogen and dispersion of nitrogenous constituents in the seeds have also been studied. Extraction of proteins of considerable purity is best effected with sodium chloride solution (5%, w/v) and subsequent dialysis of the extract. Proteins were isolated from seven varieties of leguminous seeds by acid-alkali extraction method and their protein efficiency ratio and the biological value have been evaluated by animal experiments with and without supplementing the isolated protein diets with the missing essential amino acids.     

Variability in Xanthomonads of Grain Legumes

Pulse xanthomonads could not be differed on the basis of their bacteriological propertries. Colonies from cowpea, mungbean, guar, and bean showed differences in virulence related to the degree of mucoidness than to the rate of multiplication. Very weakly virulent mutants of the bean fuscous pathogen produced distinctive reaction in bean pods. White mutants were as virulent as their yellow forms.     

Kidney derived micro-scaffolds enable HK-2 cells to develop more in-vivo like properties

Many cell lines, despite the fact that they are easy to culture, tend to lose some of their in vivo characteristics in vitro, we therefore decided to investigate whether culturing HK-2 cells on kidney derived micro-scaffolds (KMS) could improve proximal tubule functionality to these cells. Kidney derived micro-scaffolds (KMS) have been prepared that, due to the fact that they are only 300 µm in depth, allow for transfer of gasses and nutrients via diffusion whilst maintaining the kidney's intricate microstructure. Culturing HK-2 on KMS shows significant increase in expression of AQP-1, ATP1B1, SLC23A1 and SLC5A2 after 1, 2 and 3 weeks compared with HK-2 grown under standard tissue culture conditions. Additionally, very high levels of expression of CCL-2 (15–30 fold increase) and LRP-2 (25–200 fold increase) were observed when the HK-2 were grown on KMS compared with HK-2 grown under standard tissue culture conditions. Furthermore, HK-2 cells grown under standard conditions released higher levels of Il-6 and Il-8 compared with primary tubule cells (Asterand AS-9-2) and secreted no MCP-1 or RANTES as opposed to primary cells that released MCP-1 and RANTES following stimulation. However, HK-2 grown on KMS showed both a marked decrease in Il-6/Il-8 secretion in line with the primary cells and secreted MCP-1 as well. These results show that the micro-environment of the KMS assists in restoring in vivo like properties to the HK-2 cells.     

Mouse models of human genetic disease: Which mouse is more like a man?

There has always been great interest in animal models of human genetic disease, and mice provide the largest number of examples. A mutation in the homologous gene in mice does not always lead to the same phenotype as is found in man, however. Recent studies made it apparent that one mutation can have markedly different phenotypes when placed on different genetic backgrounds. This variation is due to different alleles at modifying loci in various inbred strains. Thus, if one wishes to obtain the optimal mouse model for a human disease, one needs to choose the correct genetic background as well as the correct mutation.     

Indole-3-acetic Acid (IAA) and IAA Conjugates Applied to Bean Stem Sections: IAA Content and the Growth Response

High resolution growth recording techniques and reverse isotope dilution analysis were used to study the relationship between indole-3-acetic acid (IAA) concentration and curvature of excised bean (Phaseolus vulgaris L. cv Bush Burpee Stringless) first internode sections unilaterally treated with hormone. The maximum rate of curvature occurred rapidly (within 25 minutes) and was proportional to the log of the amount of applied IAA recovered in the tissue. The rate of curvature decreased after 30 minutes although little or no lateral migration of applied IAA occurred and tissue levels of IAA increased. The biologic activity of IAA-amino acid conjugates was found to be directly related to the amount of free IAA, resulting from their hydrolysis, which could be recovered from the tissue.     

Relationships Among Rhizobia from Native Australian Legumes

Isolates from 12 legumes at three sites in Victoria showed a wide range of morphological, cultural, symbiotic, and serological properties. Isolates from Acacia longifolia var. sophorae and Kennedia prostrata were fast growing but nodulated ineffectively Macroptilium atropurpureum and all native legumes except Swainsonia lessertiifolia. Isolates from S. lessertiifolia showed anomalous properties intermediate between fast- and slow-growing rhizobia. All isolates from the other two sites were slow-growing “cowpea” rhizobia. Symbiotic effectiveness was usually poor, and there was no relationship between effectiveness and host taxonomy or serological affinities of the isolates. This is the first report of fast-growing rhizobia from temperate Australian woody legumes and the first report of the symbiotic effectiveness of native Australian legumes with indigenous rhizobia.     

Polyacrylamide-Entrapped Rhizobium as an Inoculant for Legumes

Pot experiments showed that Rhizobium japonicum cells entrapped in a polyacrylamide gel could be used as an inoculant for soybeans and compared favorably to laboratory-made peat base inoculant containing the same bacterial strain.     

Starch Granule Production During Germination in Legumes

The development of new, small starch granules in germinatingcotyledons of Phaseolus vulgaris and Vicia faba is described;axis removal inhibits their synthesis in P. vulgaris.