Chromosome banding and FISH with rDNA probe in the diploid and tetraploid loach Misgurnus anguillicaudatus

The chromosomes of the diploid and tetraploid loach Misgurnus anguillicaudatus were analyzed by staining with Ag, chromomycin A₃ (CMA₃)/distamycin A (DA), and DA/4′,6-diamidino-2-phenylindole (DAPI), and using fluorescence in situ hybridization (FISH) with 5.8S + 28S rDNA as a probe. Nucleolus organizer regions (NORs) were mapped to the telomeric region of the short arms of the largest (first) metacentric chromosome pair in the diploid loach with 2n = 50 and the homologous quartet in the tetraploid loach with 4n = 100. The NORs were positive at the same region of the first metacentric chromosome for Ag and CMA₃/DA stainings, but negative for DA/DAPI staining. Four signals at the homologs within the same quartet suggest the duplication of the entire genome from diploid to tetraploid status. However, a size difference was detected between the rDNA signals by FISH and CMA₃ banding.     

Synthesis, isolation, and characterization of endogenous beta-galactoside-binding lectins in human leukocytes

Galaptin, a beta-galactoside-binding lectin, was isolated from human buffy coat cells (peripheral leukocytes) and spleen by affinity chromatography. The molecular weight (32K) of the native buffy coat galaptin was similar to that for splenic galaptin. Their subunit molecular weight (14.5K), pI (4.60-4.85), and amino acid composition were identical. Both galaptins showed the presence of a single polypeptide when subjected to reversed-phase HPLC. Monospecific rabbit polyclonal antiserum raised against the 14.5-kDa subunit of splenic galaptin reacted with a 14.5-kDa polypeptide present in buffy coat cells, Epstein-Barr virus-immortalized B lymphoblastoid cells, and HL-60 promyelocytic leukemia cells. However, galaptin was not synthesized in vitro by buffy coat cells. Rather, a monomeric beta-galactoside-binding protein of Mr 15.5-16.5K that is immunologically distinct from galaptin was synthesized. This galactoside-binding protein was separable from galaptin by polyacrylamide gel electrophoresis and by anion-exchange chromatography. In contrast, immunoprecipitation experiments confirmed that galaptin was synthesized by the B lymphoblastoid cells. cDNA corresponding to the B lymphoblastoid cell mRNA encoding galaptin was amplified by the polymerase chain reaction. The amplified product was partially sequenced, and 299 nucleotides were identified. The derived amino acids corresponded to residues 6-65, 84-114, and 118-126 found to be present in human splenic galaptin. Immunohistochemical analyses revealed that galaptin was distributed throughout the cytoplasm of B lymphoblastoid cells rather than being localized to the cell surface.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of Dietary Linseed Oil and Propionate Precursors on Ruminal Microbial Community,Composition, and Diversity in Yanbian Yellow Cattle

The rumen microbial ecosystem is a complex system where rumen fermentation processes involve interactions among microorganisms. There are important relationships between diet and the ruminal bacterial composition. Thus, we investigated the ruminal fermentation characteristics and compared ruminal bacterial communities using tag amplicon pyrosequencing analysis in Yanbian yellow steers, which were fed linseed oil (LO) and propionate precursors. We used eight ruminally cannulated Yanbian yellow steers (510 ± 5.8 kg) in a replicated 4 × 4 Latin square design with four dietary treatments. Steers were fed a basal diet that comprised 80% concentrate and 20% rice straw (DM basis, CON). The CON diet was supplemented with LO at 4%. The LO diet was also supplemented with 2% dl-malate or 2% fumarate as ruminal precursors of propionate. Dietary supplementation with LO and propionate precursors increased ruminal pH, total volatile fatty acid concentrations, and the molar proportion of propionate. The most abundant bacterial operational taxonomic units in the rumen were related to dietary treatments. Bacteroidetes dominated the ruminal bacterial community and the genus Prevotella was highly represented when steers were fed LO plus propionate precursors. However, with the CON and LO diet plus malate or fumarate, Firmicutes was the most abundant phylum and the genus Ruminococcus was predominant. In summary, supplementing the diets of ruminants with a moderate level of LO plus propionate precursors modified the ruminal fermentation pattern. The most positive responses to LO and propionate precursors supplementation were in the phyla Bacteriodetes and Firmicutes, and in the genus Ruminococcus and Prevotella. Thus, diets containing LO plus malate or fumarate have significant effects on the composition of the rumen microbial community.     

Nitric oxide inhibits larval settlement in Amphibalanus amphitrite cyprids by repressing muscle locomotion and molting

Nitric oxide (NO) is a universal signaling molecule and plays a negative role in the metamorphosis of many biphasic organisms. Recently, the NO/cGMP (cyclic guanosine monophosphate) signaling pathway was reported to repress larval settlement in the barnacle Amphibalanus amphitrite. To understand the underlying molecular mechanism, we analyzed changes in the proteome of A. amphitrite cyprids in response to different concentrations of the NO donor sodium nitroprusside (SNP; 62.5, 250, and 1000 μM) using a label‐free proteomics method. Compared with the control, the expression of 106 proteins differed in all three treatments. These differentially expressed proteins were assigned to 13 pathways based on KEGG pathway enrichment analysis. SNP treatment stimulated the expression of heat shock proteins and arginine kinase, which are functionally related to NO synthases, increased the expression levels of glutathione transferases for detoxification, and activated the iron‐mediated fatty acid degradation pathway and the citrate cycle through ferritin. Moreover, NO repressed the level of myosins and cuticular proteins, which indicated that NO might inhibit larval settlement in A. amphitrite by modulating the process of muscle locomotion and molting.