Patterns of an elevational gradient affecting moths across the South Korean mountains: effects of geometric constraints,plants, and climate

We investigated elevational richness patterns of three moth groups (Erebidae, Geometridae, and Noctuidae) along four elevational gradients located on one northern and three southern mountains in South Korea, as well as the effects of plants and climatic factors on the diversity patterns of moths. Moths were collected with an ultraviolet light trap at 32 sites from May through October, 2013. Plant species richness and mean temperatures for January and June were acquired. Observed and estimated moth species richness was calculated and the diversity patterns with null models were compared. Species richness along four elevational gradients peaked at mid-elevations, whereas deviations occurred at elevations below mid-peak in the southern mountains and elevations higher than mid-peak on the northern mountain. Species richness curves of three moth groups also peaked at mid-elevations throughout South Korea. However, the species richness curves for Erebidae were positively skewed, indicating that a preference for lowlands, whereas curves of the Geometridae were negatively skewed, indicating a preference for highlands. The mid-peak diversity pattern between plants and moths on the Korean mountains showed an elevational breadth that overlapped between 800 and 900 m. Multiple regression analysis revealed that plant species richness and January mean temperature significantly influenced moth species richness and abundance. The rapid increase in mean annual temperature in the Korean peninsula and the unimodal elevational gradients of moths across the country suggest that an uphill shift in peak optimum elevation and changes in the highest peak of the curve will occur in the future.     

Morpho-physiology and maize grain yield under periodic soil flooding in successive selection cycles

This study was carried out to evaluate maize plants of different recurrent selection cycles of the variety (Zea mays L.—Saracura-BRS-4154) regarded to genetic gains, morphophysiology, and grain yield, achieved over the selection cycles under intermittent flooding of the soil. This variety has the capacity to survive and produce in temporarily flooded soils and was developed by the National Maize and Sorghum Research Center (EMBRAPA). The experiment was conducted in greenhouse by using ten alternating selection cycles (Cycle 1–18) and BR 107 a variety known for its susceptibility to flooding. The flooding initiated at six-leaf stage by applying 50 mm of water three times a week. At flowering, the following parameters were evaluated: rate of leaf photosynthesis, stomatal conductance, intercellular CO₂ concentration, transpiration rate, photosynthetically active leaf area, root porosity, relative chlorophyll content, grain yield, harvest index, ear length, and interval between male and female flowering. Yield as a function of root porosity and photosynthesis were also evaluated. An index was created in this study, in order to help the discussion of the characteristics evaluated, it was called “Relative Tolerance Value—RTV”, only gaseous exchange measurements was not included in this index. By the way, it was observed throughout the selection cycles an increase in all gaseous exchange parameters, being the cycle 18, the one which presented the greatest averages. RTV for leaf area showed the greatest values for cycles 7 and 18, whereas root porosity, chlorophyll relative content, and harvest index, the greater RTV values were found in cycles 17 and 18. The largest grain yield RTV was observed in cycle 7, followed by cycles 13, 15, and 18. Flooding resulted in longer Anthesis-Silking Interval, especially for the first cycles. At flooding condition, grain yield was strongly related to root porosity (R ² = 0.66). These results showed that the selection cycles of “Saracura” maize improved some morphophysiologic characters, which favor their survival in flooded environments, also resulting in higher productivity.     

Origin of human chromosome 2 revisited

Similarities in chromosome banding patterns and hornologies in DNA sequence between chromosomes of the great apes and humans have suggested that human chromosome 2 originated through the fusion of two ancestral ape chromosomes. A lot of work has been directed at understanding the nature and mechanism of this fusion. The recent availability of the human chrornosome-2-specific alpha satellite DNA probe D2Z and the human chromosome-2p-specific subtelomeric DNA probe D2S445 prompted us to attempt cross-hybridization with chromosomes of the chimpanzee (Pan troglodytes), gorilla (Gorilla gorilla) and orangutan (Pongo pygmaeus) to search for equivalent locations in the great apes and to comment on the origin of human chromosome 2. The probes gave different results. No hybridization to the chromosome-2-specific alpha satellite DNA probe was observed on the presumed homologous great ape chromosomes using both high-stringency and low-stringency post-hybridization washes, whereas the subtelomeric-DNA probe specific for chromosome 2p hybridized to telomeric sites of the short arm of chromosome 12 of all three great apes. These observations suggest an evolutionary difference in the number of alpha satellite DNA repeat units in the equivalent ape chromosomes presumably involved in the chromosome fusion. Nevertheless, complete conservation of DNA sequence of the subtelomeric repeat sequence D2S445 in the ape chromosomes is demonstrated.     

SP-A permeabilizes lipopolysaccharide membranes by forming protein aggregates that extract lipids from the membrane

Surfactant protein A (SP-A) is known to cause bacterial permeabilization. The aim of this work was to gain insight into the mechanism by which SP-A induces permeabilization of rough lipopolysaccharide (Re-LPS) membranes. In the presence of calcium, large interconnected aggregates of fluorescently labeled TR-SP-A were observed on the surface of Re-LPS films by epifluorescence microscopy. Using Re-LPS monolayer relaxation experiments at constant surface pressure, we demonstrated that SP-A induced Re-LPS molecular loss by promoting the formation of three-dimensional lipid-protein aggregates in Re-LPS membranes. This resulted in decreased van der Waals interactions between Re-LPS acyl chains, as determined by differential scanning calorimetry, which rendered the membrane leaky. We also showed that the coexistence of gel and fluid lipid phases within the Re-LPS membrane conferred susceptibility to SP-A-mediated permeabilization. Taken together, our results seem to indicate that the calcium-dependent permeabilization of Re-LPS membranes by SP-A is related to the extraction of LPS molecules from the membrane due to the formation of calcium-mediated protein aggregates that contain LPS.     

Population structure of North Atlantic and North Pacific sei whales (<Emphasis Type="Italic">Balaenoptera borealis</Emphasis>) inferred from mitochondrial control region DNA sequences and microsatellite genotypes

Currently, three stocks of sei whales (Balaenoptera borealis) are defined in the North Atlantic; the Nova Scotian, Iceland-Denmark Strait and Eastern North Atlantic stocks, which are mainly based upon historical catch and sighting data. We analyzed mitochondrial control region DNA (mtDNA) sequences and genotypes from 7 to 11 microsatellite loci in 87 samples from three sites in the North Atlantic; Iceland, the Gulf of Maine and the Azores, and compared against the North Pacific using 489 previously published samples. No statistically significant deviations from homogeneity were detected among the North Atlantic samples at mtDNA or microsatellite loci. The genealogy estimated from the mtDNA sequences revealed a clear division of the haplotypes into a North Atlantic and a North Pacific clade, with the exception of one haplotype detected in a single sample from the Azores, which was included in the North Pacific clade. Significant genetic divergence between the North Atlantic and North Pacific Oceans was detected (mtDNA Φ_ST?=?0.72, microsatellite Weir and Cockerham’s ? = 0.20; p?<?0.001). The coalescent-based estimate of the population divergence time between the North Atlantic and North Pacific populations from the sequence variation among the mtDNA sequences was at 163,000 years ago. However, the inference was limited by an absence of samples from the Southern Hemisphere and uncertainty regarding mutation rates and generation times. The estimates of inter-oceanic migration rates were low (Nm at 0.007 into the North Pacific and at 0.248 in the opposite direction). Although estimates of genetic divergence among the current North Atlantic stocks were low and consistent with the extensive range of movement observed in satellite tagged sei whales, the high uncertainty of the genetic divergence estimates precludes rejection of multiple stocks in the North Atlantic.     

Antimicrobial resistance and class I integrons in Salmonella enterica isolates from wild boars and Bísaro pigs

The antibiotic resistance phenotype and genotype and the integron type were characterized in 58 Salmonella enterica isolates recovered from Bísaro pigs and wild boars (20 S. Typhimurium, 17 S. Rissen, 14 S. Enteritidis and 7 S. Havana). Most S. Typhimurium isolates (15/20 of Bísaro pigs and wild boars) showed ampicillin, chloramphenicol, streptomycin, tetracycline, sulfonamide, and amoxicillin-clavulanic acid resistances. Of the 17 S. Rissen isolates of both origins, 13 were resistant to ampicillin, tetracycline and trimethoprim-sulfamethoxazole. Among the S. Enteritidis isolates of Bísaro pigs, eight were nalidixic acid-resistant and three were sulfonamide-resistant. The tet(A) or tet(G) genes were detected in most tetracycline-resistant isolates. The intI1 gene was identified in 72.5% of S. enterica isolates in which the conserved region 3' of class 1 integrons (qacEΔ1+sul1) was also amplified, whereas none had the intI2 gene. The dfrA12+orfF+aadA2 gene cassette arrangement was found in the variable region of class 1 integrons in 14 S. Rissen isolates. Fifteen S. Typhimurium isolates had two integrons with variable regions of 1000 and 1200 bp that harbored the aadA2 and blaPSE-1 gene cassettes, respectively. In these isolates the floR and tet(G) genes were also amplified, indicative of the genomic island 1 (SGI1). Salmonella Typhimurium and S. Rissen of animal origin frequently show a multi-antimicrobial resistant phenotype, which may have implications in public health.