Nest intrusion and infanticidal attack on nestlings in great cormorants Phalacrocorax carbo: why do adults attack conspecific chicks?

Infanticide, the killing of young animals by conspecifics, has been observed in diverse taxa. The function of infanticide has been classified as exploitation, sexual selection, parental manipulation or resource competition. We observed infanticidal behavior and its reproductive results at five breeding colonies of great cormorants from January to August 2008. Eighteen cases of nest intrusions and/or attacks toward a chick by conspecific non-nest-owners were observed, and two of them were filmed. In both attacks, perpetrators pecked the necks of chicks several times with display. The chicks bent their necks down onto the nest and remained stationary. Our data did not support the exploitation hypothesis because adult cormorants did not use chicks as food. In addition, the perpetrators were not true parents and did not mate with the female nest owner, indicating that parental manipulation and sexual selection hypotheses were unlikely explanations. On the other hand, concurrent presence of adults during prelaying and chick-rearing periods at a particular colony affected the occurrence of nest takeovers and intrusions and/or attacks, suggesting that some conflicts over nests arise between individuals that are at different stages of the breeding cycle. Digital videos relating to this article are available at and .     

Synthesis of sialyllactosamine clusters using carbosilane as core scaffolds by means of chemical and enzymatic approaches

An efficient synthesis of sialyllactosamine (SiaLacNAc) clusters using carbosilanes as core scaffolds has been accomplished by means of chemical and enzymatic approaches. N-Acetyl-d-glucosamine (GlcNAc) clusters having O-glycosidic linkage or S-glycosidic linkage were chemically synthesized from known intermediates in high yields. The GlcNAc clusters were first used as substrates for β1,4 galactosyl transferase using UDP-galactose (UDP-Gal) as a sugar source to provide corresponding N-acetyllactosamine clusters. Further sugar elongation of the LacNAc clusters was demonstrated using α2,3 sialyl transferase and CMP-neuraminic acid (CMP-NANA) to yield the corresponding SiaLacNAc clusters.     

Chemical and Immunochemical Detection of 8-Halogenated Deoxyguanosines at Early Stage Inflammation

Myeloperoxidase (MPO) generates reactive halogenating species that can modify DNA. The aim of this study was to investigate the formation of 8-halogenated 2′-deoxyguanosines (8- halo-dGs) during inflammatory events. 8-Bromo-2′-dG (8-BrdG) and 8-chloro-2′-dG (8-CldG) were generated by treatment of MPO with hydrogen peroxide at physiological concentrations of Cl⁻ and Br⁻. The formation of 8-halo-dGs with other oxidative stress biomarkers in lipopolysaccharide-treated rats was assessed by liquid chromatography tandem mass spectrometry and immunohistochemistry using a novel monoclonal antibody (mAb8B3) to 8-BrdG-conjugated keyhole limpet hemocyanin. The antibody recognized both 8-BrdG and 8-CldG. In the liver of lipopolysaccharide-treated rats, immunostaining for 8-halo-dGs, halogenated tyrosines, and MPO were increased at 8 h, whereas those of 8-oxo-2′-dG (8-OxodG) and 3-nitrotyrosine were increased at 24 h. Urinary excretion of both 8-CldG and 8-BrdG was also observed earlier than those of 8-OxodG and modified tyrosines (3-nitrotyrosine, 3-chlorotyrosine, and 3- bromotyrosine). Moreover, the levels of the 8-halo-dGs in urine from human diabetic patients were 8-fold higher than in healthy subjects (n = 10, healthy and diabetic, p < 0.0001), whereas there was a moderate difference in 8-OxodG between the two groups (p < 0.001). Interestingly, positive mAb8B3 antibody staining was observed in liver tissue from hepatocellular carcinoma patients but not in liver tissue from human cirrhosis patients. These data suggest that 8-halo-dGs may be potential biomarkers of early inflammation.     

Carbosilane dendrimers bearing globotriaoses: construction of a series of carbosilane dendrimers bearing globotriaoses

To enhance biological activities on the basis of the sugar cluster effect, a series of carbosilane dendrimers as core scaffolds for the construction of glycodendrimers was systematically synthesized from appropriate chlorosilanes by a combination of alkenylation and hydrosylation reactions. Those carbosilane dendrimers having terminal C=C double bonds underwent general hydroboration reactions to give corresponding primary polyols. Further transformations of the alcohols were then performed by mesylation followed by a displacement with NaBr to provide corresponding dendrimers with 4 to 36 bromine atoms at each terminal end. Assembly of trisaccharide moieties of globotriaosyl ceramide using alkyl halide-type carbosilane dendrimers as the core frame was conducted in liquid ammonia by a one-pot reaction involving selective removal of a benzyl group under the Birch reduction condition and subsequent S(N)2 reaction to yield a series of carbosilane dendrimers having appropriate numbers of trisaccharide moieties. These dendrimers have unique shapes and adequate numbers of terminal trisaccharide moieties. Some of the dendrimers showed unique biological activity against Stxs, which were produced by pathogenic Escherichia coli O157:H7.     

Localization and diurnal variations of carbonic anhydrase mRNA expression in the inner ear of the rainbow trout Oncorhynchus mykiss

Physiological studies have suggested that carbonic anhydrase (CA) plays a central role in otolith biomineralization via ion transport. However, the presence and exact function of CA in the inner ear have not been determined. In the present study, to investigate the localization of CA and its involvement in otolith calcification, we cloned two cDNAs encoding CAs from the rainbow trout sacculus. These two cDNAs, designated rainbow trout CAa (rtCAa) and rtCAb, both had an open reading frame encoding 260 amino acids with a sequence identity of 78%. Remarkably, rtCAb has a high degree of homology (82%) with “high activity CA” in the zebrafish, and its mRNA expression showed variation in the range 1.9–11.4 × 10⁴ copies/ng total RNA in the sacculus. In contrast, rtCAa mRNA was constantly expressed at approximately 3 × 10⁴ copies/ng total RNA. In situ hybridization revealed that rtCAb mRNA was strongly expressed in the distal squamous epithelial cells and transitional epithelial cells, except the mitochondria-rich cells, whereas, rtCAa was localized in extrasaccular tissue. These results suggest that the rtCAb isozyme is involved in the daily increment formation and calcification of otoliths via phase and spatial differences of the bicarbonate supply to the endolymph.     

Organization of the cores of the mammalian pyruvate dehydrogenase complex formed by E2 and E2 plus the E3-binding protein and their capacities to bind the E1 and E3 components

The subunits of the dihydrolipoyl acetyltransferase (E2) component of mammalian pyruvate dehydrogenase complex can form a 60-mer via association of the C-terminal I domain of E2 at the vertices of a dodecahedron. Exterior to this inner core structure, E2 has a pyruvate dehydrogenase component (E1)-binding domain followed by two lipoyl domains, all connected by mobile linker regions. The assembled core structure of mammalian pyruvate dehydrogenase complex also includes the dihydrolipoyl dehydrogenase (E3)-binding protein (E3BP) that binds the I domain of E2 by its C-terminal I' domain. E3BP similarly has linker regions connecting an E3-binding domain and a lipoyl domain. The composition of E2.E3BP was thought to be 60 E2 plus approximately 12 E3BP. We have prepared homogenous human components. E2 and E2.E3BP have s(20,w) values of 36 S and 31.8 S, respectively. Equilibrium sedimentation and small angle x-ray scattering studies indicate that E2.E3BP has lower total mass than E2, and small angle x-ray scattering showed that E3 binds to E2.E3BP outside the central dodecahedron. In the presence of saturating levels of E1, E2 bound approximately 60 E1 and maximally sedimented 64.4 +/- 1.5 S faster than E2, whereas E1-saturated E2.E3BP maximally sedimented 49.5 +/- 1.4 S faster than E2.E3BP. Based on the impact on sedimentation rates by bound E1, we estimate fewer E1 (approximately 12) were bound by E2.E3BP than by E2. The findings of a smaller E2.E3BP mass and a lower capacity to bind E1 support the smaller E3BP substituting for E2 subunits rather than adding to the 60-mer. We describe a substitution model in which 12 I' domains of E3BP replace 12 I domains of E2 by forming 6 dimer edges that are symmetrically located in the dodecahedron structure. Twelve E3 dimers were bound per E248.E3BP12 mass, which is consistent with this model.     

Production of recombinant human relaxin 3 in AtT20 cells

Relaxin 3 has been reported recently as a member of the insulin/IGF/relaxin family. To clarify the function of relaxin 3, we prepared recombinant human relaxin 3 using a mouse adrenocorticotrophic hormone (ACTH)-secreting cell line, AtT20. To detect a mature form of recombinant human relaxin 3, a competitive enzyme immunoassay (EIA) was developed using a monoclonal antibody (mAb; HK4-144-10), which was raised for the N-terminal peptide of human relaxin 3 A-chain. We detected immunoreactive (ir-) relaxin 3 in the culture supernatant of AtT20 cells stably transfected with human relaxin 3 cDNA. After treatment with 5 microM forskolin for 3 days, the concentration of the ir-relaxin 3 in the culture supernatant reached 12 nM. Ir-relaxin 3 was purified from the culture supernatant by a combination of various chromatographies. By analyses of N-terminal amino acid sequence and electrospray ionization mass spectrometry (ESI-MS), we confirmed that the purified material was a mature form of human relaxin 3. The recombinant human relaxin 3 thereby obtained increased intracellular cAMP production in THP-1 cells. Our results demonstrate that the expression of relaxin 3 cDNA in AtT20 cells is a useful tool to produce a bioactive and mature form of relaxin 3.