Man Alpha Research Articles

A NEW METHOD FOR ACCURATE PREDICTION OF SPERMATOGENESIS: FSH/T AND T IN SEMINAL PLASMA

A NEW METHOD FOR ACCURATE PREDICTION OF SPERMATOGENESIS: FSH/T AND T IN SEMINAL PLASMA

A Peptide-Lectin Fusion Strategy for Developing a Glycan Probe for Use in Various Assay Formats.

While nucleic acid and protein analysis approaches continue to see significant breakthroughs, analytical strategies for glycan determination have by comparison seen slower technological advances. Here we provide a strategy for glycan probe development using an engineered lectin fusion that can be incorporated into various common pathology lab assay formats including Western blot and agglutination assays. In this proof of concept, we use the natural lectin, Pseudomonas fluorescens agglutinin (PFA), capable of binding core Man alpha(1-3)-Man alpha(1-6)-Man units, where this lectin has previously been shown to bind to the glycans presented by the gp120 coat protein of (HIV) Human Immunodeficiency Virus. In our strategy, we engineered the lectin to possess a fusion of the biotin mimetic tag equence of amino acids V-S-H-P-Q-A-P-F. With the glycan receptive PFA directly linked to the biotin mimic, we could facilitate a probe for various standard clinical assay formats by virtue of coupling to streptavidin-HRP (horseradish peroxidase) or streptavidin beads for Western blot and agglutination assays respectively. We found the PFA fusion retained low nanomolar affinity for gp120 by ELISA (Enzyme Linked Immunosorbent Assay) and microscale thermophoresis. This probe engineering strategy proved effective in the relevant assay formats that may now allow detection for the presence of glycans containing the core Man alpha(1-3)-Man alpha(1-6)-Man units recognized by PFA.

Postrelease monitoring habitat selection by reintroduced burchell's zebra and blue wildebeest in southern Mozambique.

AimIn Africa, reintroduction of wild animal species to conservation areas is a common practice, for the recovery or restoration of populations. Effective monitoring of reintroduced species requires understanding of basic ecological requirements such as habitat selection of these species in the new environment. Therefore, the present study investigated the habitat selection of zebra and wildebeest following their reintroduction into Maputo Special Reserve, south Mozambique, and we use binary logistic analyses to investigate the relative influence of biotic and abiotic factors in determining the habitat use.LocationMaputo Special Reserve, south Mozambique.MethodsWe conducted the study from July 2016 to June 2017. The data were collected by direct observation, driving the vehicle along the reserve's roads that covered the vegetation communities where zebras and wildebeest are known to commonly occur. Habitat selection was calculated using selection indices (Manly's alpha), and binary logistic analyses were used to investigate the relative influence of biotic and abiotic factors in determining the habitat use.ResultsThe arboreal savanna was the preferred habitat by both herbivore species. Habitat use of zebra appeared to be strongly determined by characteristics such as high grass cover, high grass greenness, and distance to water, while the habitat use by wildebeest, was strongly affected by grass height.Main conclusionsBoth zebra and wildebeest prefer arboreal savanna, forage selection likely drove preference of this habitat. Greater grass cover and greater percentage greenness of the grass both significantly increased the odds of zebra use of habitat, whereas the odds of use decreased with increases in distance to water, meaning an opportunity to ingest large amounts of grass biomass with higher quality, and this opportunity decreases with increasing in distance to water. Grass height was in the highest‐ranking model predicting habitat use by wildebeest, and during the dry season the use of habitat increased with increasing grass height, suggesting that selecting areas with tall grasses by wildebeest equated to choosing areas with higher grass quantity, as the food intake rate increases with grass height.

ON DRILLING FREQUENCY AND MANLY'S ALPHA: TOWARDS A NULL MODEL FOR PREDATOR PREFERENCE IN PALEOECOLOGY

In the paleoecological literature, drilling frequency—the percent of specimens in a prey taxon with complete drill holes—is commonly interpreted as an indication of a predator's preference. Such taxon-specific drilling frequencies are often compared with one another and related to underlying prey characteristics such as cost-benefit ratio or body size. Although this approach can demonstrate a predator's relative preference for one prey type over another, it fails to consider whether predation on any prey type is greater than would be expected by a predator without preference. Here we develop a null model for evaluating predator preference in paleoecology by considering drilling frequency in the framework of Manly's alpha, which is a well-established model in the ecological literature that has been used to evaluate predator preferences. In effect, Manly's alpha normalizes taxon-specific drilling frequencies with all potential prey types in the community, allowing for a statistically rigorous test of the null hypothesis that drilling predation, and therefore predator preference, on any given prey type is equivalent to all other available prey types in the community. After discussing the statistical basis for the model, we demonstrate the model's utility by applying it to a published dataset of drilling predation on Pliocene bivalves from Langenboom, Netherlands. The Manly's alpha approach, which uses the same data (i.e., drilling frequencies) that are commonly collected by paleoecologists, provides a null hypothesis to more rigorously assess predator preferences and inherently includes community context for predator-prey interactions in the fossil record.

Hunting affects dry season habitat selection by several bovid species in northern Benin

Multiple land uses including tourism, hunting, and agriculture around protected areas can be a serious complication for wildlife management. We calculated habitat selection indices (Manly's alpha) for 10 bovid species in the Pendjari Biosphere Reserve in Benin, west Africa, to assess if habitat use differed in each bovid species between hunting and non‐hunting zones. Presence/absence data was used in resource‐selection functions based on a generalized linear mixed effect model to examine factors that explained bovid species distribution. We observed stronger avoidance of open habitat types in the hunting zone than in the non hunting zone for the hartebeest Alcelaphus buselaphus, oribi Ourebia ourebi, roan Hippotragus equines, kob Kobus kob, Waterbuck Kobus ellipsiprymnus defassa and reedbuck Redunca redunca. In contrast, in grey duiker Sylvicapra grimmia, red‐flanked duiker Cephalophus rufilatus, bushbuck Tragelaphus scriptus and buffalo Syncerus caffer we found no differences in habitat use between hunted and non‐hunted areas. This may indicate that the latter species show more pronounced ecological and behavioural plasticity. Further, resource selection of bovid species on a small scale was influenced by other factors such as habitat structure, landscape characteristics, and human disturbance. This preliminary assessment of bovid habitat relationships in west Africa suggests that human hunting activities may cause species to alter their habitat selection. We therefore suggest habitat models may need to incorporate this source of variation if they are to accurately predict habitat use or distribution of a species.

Effects of resource limitation on habitat usage by the browser guild in Hluhluwe-iMfolozi Park, South Africa

Abstract:Resource depletion and associated increases in interspecific competition are likely to influence differential habitat usage amongst a guild. We tested some prominent theoretical concepts using observed differences in seasonal habitat use amongst the savanna browser guild (elephant, giraffe, impala, kudu and nyala) in Hluhluwe-iMfolozi Park, South Africa. Herbivore locations (n = 3108) were recorded over 2 y using repeated road transects and, for elephant, GPS collars (187 254 downloads). Densities were calculated using a novel GIS approach designed to be a cost-effective method for annual censuses, but also able to cope with abrupt changes in visibility. Selectivity for (Manly's α) vegetation types, and overlap (Schoener's index) in vegetation type usage were calculated. Resource depletion in the dry season resulted in all members of the guild increasing selectivity for vegetation types (sum of absolute values away from the neutral value for Manly's alpha for the guild: dry seasons 3.97, 5.16; corresponding wet seasons 3.12, 3.68), but decreasing interspecific overlap (80% of Schoener's indices lower in dry season versus wet season). These effects were more marked over the second, more severe, dry season. We found support for the niche overlap hypothesis and the niche compression hypothesis. The Jarman–Bell principle was generally supported, although unexpectedly during the severe dry season elephant showed the most selectivity for vegetation type. The greater the resource depletion, the more relevant interspecific differences in habitat usage become in relation to the differential impacts of guild members.

Seasonal Selection Preferences for Woody Plants by Breeding Herds of African Elephants (Loxodonta africana) in a Woodland Savanna

To evaluate dynamics of elephant herbivory, we assessed seasonal preferences for woody plants by African elephant breeding herds in the southeastern part of Kruger National Park (KNP) between 2002 and 2005. Breeding herds had access to a variety of woody plants, and, of the 98 woody plant species that were recorded in the elephant's feeding areas, 63 species were utilized by observed animals. Data were recorded at 948 circular feeding sites (radius 5 m) during wet and dry seasons. Seasonal preference was measured by comparing selection of woody species in proportion to their estimated availability and then ranked according to the Manly alpha (α) index of preference. Animals demonstrated a selection preference in feeding on woody vegetation, andGrewia hexamita, Grewia bicolor, Grewia flavescens, andGrewia monticolawere selected consistently more over all seasons. In addition, our results indicate that elephant herds have a low preference for at least some of the woody species prone to extirpation and that feeding preferences for woody plants do not account for the association of elephants and riparian fringe habitat.

Structural Basis of the Anti-HIV Activity of the Cyanobacterial Oscillatoria Agardhii Agglutinin

The cyanobacterial Oscillatory Agardhii agglutinin (OAA) is a recently discovered HIV-inactivating lectin that interacts with high-mannose sugars. Nuclear magnetic resonance (NMR) binding studies between OAA and α3,α6-mannopentaose (Manα(1-3)[Manα(1-3)[Manα(1-6)]Manα(1-6)]Man), the branched core unit of Man-9, revealed two binding sites at opposite ends of the protein, exhibiting essentially identical affinities. Atomic details of the specific protein-sugar contacts in the recognition loops of OAA were delineated in the high-resolution crystal structures of free and glycan-complexed protein. No major changes in the overall protein structure are induced by carbohydrate binding, with essentially identical apo- and sugar-bound conformations in binding site 1. A single peptide bond flip at W77-G78 is seen in binding site 2. Our combined NMR and crystallographic results provide structural insights into the mechanism by which OAA specifically recognizes the branched Man-9 core, distinctly different from the recognition of the D1 and D3 arms at the nonreducing end of high-mannose carbohydrates by other antiviral lectins.

A designed chimeric cyanovirin‐N homolog lectin: Structure and molecular basis of sucrose binding

The NMR and X-ray structures of a designed chimeric cyanovirin-N homolog (CVNH) protein were determined. The individual halves of the structure are similar to their counterparts in the parent proteins, with domains A and B resembling the structures of TbCVNH and NcCVNH, respectively. No significant differences between the solution and crystal conformations were observed, although details in loop conformations and distinct crystal packing-induced features are present. Carbohydrate binding studies by NMR revealed affinity and specificity for Glc alpha(1-2)Frc and Man alpha(1-2)Man, and the parental half that is devoid of any sucrose affinity in NcCVNH was transformed into a genuine sucrose binding site in the context of the chimera. The atomic details of sugar recognition are seen in the crystal structure of the protein with two bound Glc alpha(1-2)Frc molecules. Both sugars exhibit different conformations around the glycosidic bond and engage in unique hydrogen bonding networks in the two sites. Although the protein is able to bind two Man alpha(1-2)Man molecules, a property associated with HIV-inactivation, no anti-HIV activity was observed for the hybrid protein. These results provide the structural basis for sugar recognition in the CVNH family and aid in deciphering the relationship between sugar binding and anti-HIV activity.

Novel Anti-Glycan Antibodies Related to Inflammatory Bowel Disease Diagnosis and Phenotype

We sought to evaluate whether two novel immunoglobulin A (IgA) cell wall polysaccharide antibodies, anti-laminarin (anti-L) and anti-chitin (anti-C), aid in the diagnosis and phenotype differentiation of Crohn's disease (CD) and ulcerative colitis (UC). A cohort of 818 individuals with inflammatory bowel disease (IBD; 517 CD and 301 UC) from two IBD tertiary referral centers, with median ages of 33 and 39 years, respectively, and disease duration of 8.9 years, were phenotyped using the Montreal classification, and analyzed for seven anti-glycan antibodies (gASCA (anti-Saccharomyces cerevisiae) IgG, gASCA IgA, anti-chitobioside (GlcNAc(beta1,4)GlcNAc(beta)), anti-laminaribioside (Glc(beta1,3)Glb(beta)), anti-mannobioside (Man(alpha1,3)Man(alpha)), anti-L, and anti-C) and perinuclear atypical neutrophil cytoplasmic antibodies (pANCA). In the CD patient population, 73% were positive for >/=1 anti-glycan antibody. All glycan markers were specific for CD (85.4-97.7%) and more prevalent in CD vs. UC (P<0.0015). gASCA IgG and IgA best differentiated CD from UC followed by anti-L (area under the curve 0.818, 0.815, and 0.702, respectively). The addition of anti-L and anti-C to gASCA IgG and pANCA improved discrimination between CD and UC (P<0.001). Adding anti-L to gASCA and pANCA differentiated colonic CD and UC (P=0.02). An increasing number of positive antibodies was associated with early CD onset, penetrating phenotype, perianal disease, and the need for surgery (P<0.001). Anti-L was associated with ileocolonic CD (odds ratio (OR) 2.28, 95% confidence interval (CI) 1.40-3.69; P=0.001), and anti-C with penetrating (OR 2.75, 95% CI 1.50-5.04; P=0.001) and perianal disease (OR 1.95, 95% CI 1.06-3.59; P=0.03). Anti-L and anti-C improve differentiation between CD and UC. Anti-L may also differentiate between isolated colonic CD and UC. Both anti-L and anti-C are independently associated with a more aggressive CD phenotype.

Intervening with Urinary Tract Infections Using Anti-Adhesives Based on the Crystal Structure of the FimH–Oligomannose-3 Complex

Background Escherichia coli strains adhere to the normally sterile human uroepithelium using type 1 pili, that are long, hairy surface organelles exposing a mannose-binding FimH adhesin at the tip. A small percentage of adhered bacteria can successfully invade bladder cells, presumably via pathways mediated by the high-mannosylated uroplakin-Ia and α3β1 integrins found throughout the uroepithelium. Invaded bacteria replicate and mature into dense, biofilm-like inclusions in preparation of fluxing and of infection of neighbouring cells, being the major cause of the troublesome recurrent urinary tract infections.Methodology/Principal FindingsWe demonstrate that α-d-mannose based inhibitors of FimH not only block bacterial adhesion on uroepithelial cells but also antagonize invasion and biofilm formation. Heptyl α-d-mannose prevents binding of type 1-piliated E. coli to the human bladder cell line 5637 and reduces both adhesion and invasion of the UTI89 cystitis isolate instilled in mouse bladder via catheterization. Heptyl α-d-mannose also specifically inhibited biofilm formation at micromolar concentrations. The structural basis of the great inhibitory potential of alkyl and aryl α-d-mannosides was elucidated in the crystal structure of the FimH receptor-binding domain in complex with oligomannose-3. FimH interacts with Manα1,3Manβ1,4GlcNAcβ1,4GlcNAc in an extended binding site. The interactions along the α1,3 glycosidic bond and the first β1,4 linkage to the chitobiose unit are conserved with those of FimH with butyl α-d-mannose. The strong stacking of the central mannose with the aromatic ring of Tyr48 is congruent with the high affinity found for synthetic inhibitors in which this mannose is substituted for by an aromatic group.Conclusions/SignificanceThe potential of ligand-based design of antagonists of urinary tract infections is ruled by the structural mimicry of natural epitopes and extends into blocking of bacterial invasion, intracellular growth and capacity to fluxing and of recurrence of the infection.

Structural Insights into the Mechanism of pH-dependent Ligand Binding and Release by the Cation-dependent Mannose 6-Phosphate Receptor

The cation-dependent mannose 6-phosphate receptor (CD-MPR) is a key component of the lysosomal enzyme targeting system that binds newly synthesized mannose 6-phosphate (Man-6-P)-containing acid hydrolases and transports them to endosomal compartments. The interaction between the MPRs and its ligands is pH-dependent; the homodimeric CD-MPR binds lysosomal enzymes optimally in the pH environment of the trans Golgi network (pH approximately 6.5) and releases its cargo in acidic endosomal compartments (<pH 5.5) and at the cell surface. In addition, CD-MPR binding affinities are modulated by divalent cations. Our previous crystallographic studies have shown that at pH 6.5, the CD-MPR bound to Man-6-P adopts a significantly different quaternary conformation than the CD-MPR in a ligand-unbound state, a feature unique among known lectin structures. To determine whether different pH conditions elicit conformational changes in the receptor that alters ligand binding affinities, we have obtained additional crystal structures representative of the various environments encountered by the receptor including: 1) the CD-MPR bound at pH 6.5 (i.e. trans Golgi network) to a high affinity ligand (the terminally phosphorylated trisaccharide P-Man(alpha1,2)Man(alpha1,2)Man-O-(CH(2))(8)COOMe), 2) the CD-MPR at pH 4.8 in an unbound state (i.e. endosome), and 3) the CD-MPR at pH 7.4 (i.e. cell surface). A detailed comparison of the available CD-MPR structures reveals the positional invariability of specific binding pocket residues and implicates intermonomer contact(s), as well as the protonation state of Man-6-P, as regulators of pH-dependent carbohydrate binding.

Primary Structure and Carbohydrate Binding Specificity of a Potent Anti-HIV Lectin Isolated from the Filamentous Cyanobacterium Oscillatoria agardhii

The primary structure of a lectin, designated Oscillatoria agardhii agglutinin (OAA), isolated from the freshwater cyanobacterium O. agardhii NIES-204 was determined by the combination of Edman degradation and electron spray ionization-mass spectrometry. OAA is a polypeptide (Mr 13,925) consisting of two tandem repeats. Interestingly, each repeat sequence of OAA showed a high degree of similarity to those of a myxobacterium, Myxococcus xanthus hemagglutinin, and a marine red alga Eucheuma serra lectin. A systematic binding assay with pyridylaminated oligosaccharides revealed that OAA exclusively binds to high mannose (HM)-type N-glycans but not to other N-glycans, including complex types, hybrid types, and the pentasaccharide core or oligosaccharides from glycolipids. OAA did not interact with any of free mono- and oligomannoses that are constituents of the branched oligomannosides. These results suggest that the core disaccharide, GlcNAc-GlcNAc, is also essential for binding to OAA. The binding activity of OAA to HM type N-glycans was dramatically decreased when alpha1-2 Man was attached to alpha1-3 Man branched from the alpha1-6 Man of the pentasaccharide core. This specificity of OAA for HM-type oligosaccharides is distinct from other HM-binding lectins. Kinetic analysis with an HM heptasaccharide revealed that OAA possesses two carbohydrate binding sites per molecule, with an association constant of 2.41x10(8) m-1. Furthermore, OAA potently inhibits human immunodeficiency virus replication in MT-4 cells (EC50=44.5 nm). Thus, we have found a novel lectin family sharing similar structure and carbohydrate binding specificity among bacteria, cyanobacteria, and marine algae.

Seasonal Diet and Foraging Preference of Greater Kudu Tragelaphus Strepsiceros in the Llano Uplift of Texas

The greater kudu Tragelaphus strepsiceros, a large African herbivore, occupies the browser trophic niche. This species has been introduced into selected areas of Texas inhabited by the white-tailed deer Odocoileus virginianus, a native browser. Based on similar trophic function, potential interspecific competition could exist between these two species. The objectives of our study were to: 1) describe the seasonal diets of greater kudu in Texas and 2) determine if greater kudu show preference for plants that might create competition with white-tailed deer. We documented the seasonal diet and forage preference of greater kudu at Mason Mountain Wildlife Management Area from 15 May 2001 to 25 February 2002 by identifying epidermal fragments of plants in faecal pellets. We identified and quantified 49 species of plants eaten by greater kudu. Annually, browse made up 80.2% of the diet, while 7.6% mast, 6.5% grasses, 3% forbs and 2.7% unidentified material comprised the remaining parts of their diet. Important browse species included Texas/blackjack oak Quercus buckleyi/Q. marilandica, plateau live oak Q. fusiformis, Ashe juniper Juniperus ashei, mesquite Prosopis glandulosa, prickly pear Opuntia sp., flameleaf sumac Rhus lanceolata, and Texas persimmon Diospyros texana. We measured availability of forage plants by quadrat and line intercept methods concurrent with faecal pellet collection. We compared plant use (dietary composition) with plant availability and assessed forage preference by greater kudu using log-likelihood χ2-tests with Bonferroni corrected confidence intervals and Manly's alpha indices. We detected statistically significant differences between plant use and availability (P < 0.05). Purple horsemint Monarda citriodora, Canada wildrye Elymus canadensis, mesquite, flameleaf sumac, Texas/blackjack oak and Ashe juniper were preferred species. Relative preference of general forage categories by greater kudu in Texas was similar to that reported from Africa. Based on our findings, greater kudu could compete with white-tailed deer for browse forage.

Purification of 3 monomeric monocot mannose-binding lectins and their evaluation for antipoxviral activity: potential applications in multiple viral diseases caused by enveloped viruses

Three monomeric monocot lectins from Zephyranthes carinata, Zephyranthes candida, and Gloriosa superba with carbohydrate specificity towards mannose derivatives and (or) oligomannose have been isolated and purified from their storage tissues. The lectins were purified by anion-exchange chromatography on DEAE-Sephacyl and by gel filtration chromatography on Biogel P-200 followed by high-performance liquid chromatography. The purified lectins, Z. carinata, Z. candida, and G. superba had molecular masses of 12, 11.5, and 12.5 kDa, respectively, as determined by gel filtration and SDS-PAGE, indicating that they are monomers. In a hapten inhibition assay, methyl-alpha-D-mannopyranoside inhibited agglutination of both Z. candida and Z. carinata; the latter was also inhibited by Man(alpha1-2)Man and Man(alpha1-3)Man. Gloriosa superba showed inhibition only with Man(alpha1-4)Man of all of the sugars and glycoproteins tested. All purified lectins agglutinated red blood cells from rabbit, whereas G. superba was also reactive towards erythrocytes from guinea pig. All of the lectins were nonglycosylated and did not require metal ions for their activity. They were labile above 60 degrees C and were affected by denaturing agents such as urea, thiourea, and guanidine-HCl. The lectins were virtually nonmitogenic, like other members of Amaryllidaceae and Liliaceae. Of the 3 lectins, G. superba was found to be highly toxic to the BSC-1 cell line (African green monkey kidney epithelial cells), while both of the Zephyranthes species showed significant in vitro inhibition of poxvirus replication in BSC-1 cells without any toxic effects to the cells. In addition, Z. candida also exhibited significant anticancer activity against SNB-78, a CNS human cancer cell line.

Kinetic properties and substrate specificities of two recombinant human N-acetylglucosaminyltransferase-IV isozymes

N-acetylglucosaminyltransferase (GnT)-IV catalyzes the formation of the GlcNAcbeta1-4 branch on the GlcNAcbeta1-2Manalpha1-3 arm of the core structure of N-glycans. Two human GnT-IV isozymes (GnT-IVa and GnT-IVb) had been identified, which exhibit different expression profiles among human tissues and cancer cell lines. To clarify the enzymatic properties of the respective enzymes, their kinetic parameters were determined using recombinant full-length enzymes expressed in COS7 cells. The K (m) of human GnT-IVb for UDP-GlcNAc was estimated to be 0.24 mM, which is 2-fold higher than that of human GnT-IVa. The K (m) values of GnT-IVb for pyridylaminated (PA) acceptor sugar chains with different branch numbers were 3- to 6-fold higher than those of GnT-IVa. To compare substrate specificities more precisely, we generated recombinant soluble enzymes of human GnT-IVa and GnT-IVb with N-terminal flag tags. Both enzymes showed similar substrate specificities as determined using fourteen PA-sugar chains. They preferred complex-type N-glycans over hybrid-types. Among the complex-type N-glycans tested, the relative activities of both enzymes were increased in proportion to the number of GlcNAc branches on the Man alpha1-6 arm. The Man alpha1-6 arm of the acceptors was not essential for their activities because a linear pentasaccharide lacking this arm, GlcNAcbeta1-2Manalpha1-3Manbeta1-4GlcNAcbeta1-4 GlcNAc-PA, was a substrate for both enzymes. These results indicate that human GnT-IVb exhibits the same acceptor substrate specificities as human GnT-IVa, although GnT-IVb has lower affinities for donors or acceptors than GnT-IVa. This suggests that GnT-IVa is more active than GnT-IVb under physiological conditions and that it primarily contributes to the biosynthesis of N-glycans.

New crystal forms of Diocleinae lectins in the presence of different dimannosides.

Studying the interactions between lectins and sugars is important in order to explain the differences observed in the biological activities presented by the highly similar proteins of the Diocleinae subtribe. Here, the crystallization and preliminary X-ray data of Canavalia gladiata lectin (CGL) and C. maritima lectin (CML) complexed with Man(alpha1-2)Man(alpha1)OMe, Man(alpha1-3)Man(alpha1)OMe and Man(alpha1-4)Man(alpha1)OMe in two crystal forms [the complexes with Man(alpha1-3)Man(alpha1)OMe and Man(alpha1-4)Man(alpha1)OMe crystallized in space group P3(2) and those with Man(alpha1-2)Man(alpha1)OMe crystallized in space group I222], which differed from those of the native proteins (P2(1)2(1)2 for CML and C222 for CGL), are reported. The crystal complexes of ConA-like lectins with Man(alpha1-4)Man(alpha1)OMe are reported here for the first time.

Facile Synthesis of Oligosaccharide Probes for the Analysis of Protein–Carbohydrate Interactions

A strategy for facile oligosaccharide synthesis is described. It obviates chromatographic separation of intermediates and enables the isolation of desired oligomers with capture-release purification and reverse-phase silica-gel cartridge separation. As an example, preparation of monoglucosylated mannotetraose (Glc alpha1-->3Man alpha1-->2Man1alpha-->2Man1alpha-->3Man beta) was conducted. After sequential glycosylation, capture-release purification with Cys-resin, global deprotection, and reverse-phase silica-gel cartridge separation, the target pentasaccharide was isolated, while isolation of shorter oligomers that lack nonreducing-end residues (Man alpha1-->2Man1alpha-->2Man1alpha-->3Man beta, Man1alpha-->2Man1alpha-->3Man beta, Man1alpha-->3Man beta) was also achieved. These products were connected to a thiol-containing linker and immobilized on Au-coated chips. Their affinity to recombinant calreticulin was evaluated by quartz-crystal microbalance.

Structural basis for the recognition of complex‐type biantennary oligosaccharides by Pterocarpus angolensis lectin

The crystal structure of Pterocarpus angolensis lectin is determined in its ligand-free state, in complex with the fucosylated biantennary complex type decasaccharide NA2F, and in complex with a series of smaller oligosaccharide constituents of NA2F. These results together with thermodynamic binding data indicate that the complete oligosaccharide binding site of the lectin consists of five subsites allowing the specific recognition of the pentasaccharide GlcNAc beta(1-2)Man alpha(1-3)[GlcNAc beta(1-2)Man alpha(1-6)]Man. The mannose on the 1-6 arm occupies the monosaccharide binding site while the GlcNAc residue on this arm occupies a subsite that is almost identical to that of concanavalin A (con A). The core mannose and the GlcNAc beta(1-2)Man moiety on the 1-3 arm on the other hand occupy a series of subsites distinct from those of con A.

Prey partitioning between cod (Gadus morhua) and minke whale (Balaenoptera acutorostrata) in the Barents Sea

Stomach samples of minke whale (Balaenoptera acutorostrata) and cod (Gadus morhua) were collected on the northeastern parts of the Finnmark coast, northern Norway, in 1998 and 1999 to investigate prey preference, niche overlap and niche width for the two species. A survey to estimate prey abundance was also conducted. Prey preference, niche overlap and niche width were described using Manly's alpha (α), Pianka's index (Ojk) and Levin's index (B), respectively. The diet of cod consisted mainly of capelin, deep-water shrimp, gadoids and krill. The smallest cod (≤64 cm length) preferred capelin, whereas the largest cod (>64 cm length) preferred gadoid species, including cod. The minke whale diet consisted mainly of capelin (Mallotus villosus), herring (Clupea harengus) and krill, and showed a particular preference for herring and capelin. Krill were consumed in large quantities, but did not seem to be a preferred food item for either cod or minke whales. In contrast to cod, which fed very little on herring, the minke whale fed heavily on herring in some areas. The niche widths for both cod and minke whales were relatively low, and the diet overlap between minke whale and cod was low.