Coolidge effect in pond snails: male motivation in a simultaneous hermaphrodite

Background  

The simultaneously hermaphroditic pond snail, Lymnaea stagnalis, can mate in the male and female role, but within one copulation only one sexual role is performed at a time. Previous work has shown that male motivation is determined by the availability of seminal fluid in the prostate gland, which is detected via a nervous connection by the brain area controlling male behaviour. Based on this knowledge, patterns of sexual role alternations within mating pairs can be explained.     

Global and regional brain metabolic scaling and its functional consequences

Background  

Information processing in the brain requires large amounts of metabolic energy, the spatial distribution of which is highly heterogeneous, reflecting the complex activity patterns in the mammalian brain.     

Expression study of <Emphasis Type="Italic">cadherin7</Emphasis> and <Emphasis Type="Italic">cadherin20</Emphasis> in the embryonic and adult rat central nervous system

Background  

Vertebrate classic cadherins are divided into type I and type II subtypes, which are individually expressed in brain subdivisions (e.g., prosomeres, rhombomeres, and progenitor domains) and in specific neuronal circuits in region-specific manners. We reported previously the expression of cadherin19 (cad19) in Schwann cell precursors. Cad19 is a type II classic cadherin closely clustered on a chromosome with cad7 and cad20. The expression patterns of cad7 and cad20 have been reported previously in chick embryo but not in the developing and adult central nervous system of mammals. In this study, we identified rat cad7 and cad20 and analyzed their expression patterns in embryonic and adult rat brains.     

Search for computational modules in the <Emphasis Type="Italic">C. elegans</Emphasis>brain

Background  

Does the C. elegans nervous system contain multi-neuron computational modules that perform stereotypical functions? We attempt to answer this question by searching for recurring multi-neuron inter-connectivity patterns in the C. elegans nervous system's wiring diagram.     

Gene-interleaving patterns of synteny in the Saccharomyces cerevisiae genome: are they proof of an ancient genome duplication event?

Background  

Recent comparative genomic studies claim local syntenic gene-interleaving relationships in Ashbya gossypii and Kluyveromyces waltii are compelling evidence for an ancient whole-genome duplication event in Saccharomyces cerevisiae. We here test, using Hannenhalli-Pevzner rearrangement algorithms that address the multiple genome rearrangement problem, whether syntenic patterns are proof of paleopolyploidization.     

Minor shift in background substitutional patterns in the Drosophila saltans and willistoni lineages is insufficient to explain GC content of coding sequences

Background  

Several lines of evidence suggest that codon usage in the Drosophila saltans and D. willistoni lineages has shifted towards a less frequent use of GC-ending codons. Introns in these lineages show a parallel shift toward a lower GC content. These patterns have been alternatively ascribed to either a shift in mutational patterns or changes in the definition of preferred and unpreferred codons in these lineages.     

Soil moisture effect on bacterial and fungal community in Beilu River (Tibetan Plateau) permafrost soils with different vegetation types

Aim

This study investigated the effects of environmental variables on the bacterial and fungal communities of the Beilu River (on the Tibetan Plateau) permafrost soils with different vegetation types.

Methods and Results

Microbial communities were sampled from meadow, steppe and desert steppe permafrost soils during May, June, August and November, and they were analysed by both pyrosequencing and the use of Biolog EcoPlates. The dominant bacterial and fungal phyla in meadow and steppe soils were Proteobacteria and Ascomycota, whereas Actinobacteria and Basidiomycota predominated in desert steppe soils. The bacterial communities in meadow soils degraded amines and amino acids very rapidly, while polymers were degraded rapidly by steppe communities. The RDA patterns showed that the microbial communities differed greatly between meadow, steppe and desert steppe, and they were related to variations in the soil moisture, C/N ratio and pH. A UniFrac analysis detected clear differences between the desert steppe bacterial community and others, and seasonal shifts were observed. The fungal UniFrac patterns differed significantly between meadow and steppe soils. There were significant correlations between the bacterial diversity (H′) and soil moisture (r = 0·506) and C/N (r = 0·527). The fungal diversity (Hf′) was significantly correlated with the soil pH (r = 0·541).

Conclusion

The soil moisture, C/N ratio and pH were important determinants of the microbial community structure in Beilu River permafrost soils.

Significance and Impact of the Study

These results may provide a useful baseline for predicting the variation in microbial communities in response to climate changes.     

Evolutionary history of <Emphasis Type="Italic">Wolbachia</Emphasis> infections in the fire ant <Emphasis Type="Italic">Solenopsis invicta</Emphasis>

Background  

Wolbachia are endosymbiotic bacteria that commonly infect numerous arthropods. Despite their broad taxonomic distribution, the transmission patterns of these bacteria within and among host species are not well understood. We sequenced a portion of the wsp gene from the Wolbachia genome infecting 138 individuals from eleven geographically distributed native populations of the fire ant Solenopsis invicta. We then compared these wsp sequence data to patterns of mitochondrial DNA (mtDNA) variation of both infected and uninfected host individuals to infer the transmission patterns of Wolbachia in S. invicta.     

Expression profiling and integrative analysis of the <Emphasis Type="Italic">CESA</Emphasis>/<Emphasis Type="Italic">CSL</Emphasis> superfamily in rice

Background  

The cellulose synthase and cellulose synthase-like gene superfamily (CESA/CSL) is proposed to encode enzymes for cellulose and non-cellulosic matrix polysaccharide synthesis in plants. Although the rice (Oryza sativa L.) genome has been sequenced for a few years, the global expression profiling patterns and functions of the OsCESA/CSL superfamily remain largely unknown.     

The caudal regeneration blastema is an accumulation of rapidly proliferating stem cells in the flatworm Macrostomum lignano

Background  

Macrostomum lignano is a small free-living flatworm capable of regenerating all body parts posterior of the pharynx and anterior to the brain. We quantified the cellular composition of the caudal-most body region, the tail plate, and investigated regeneration of the tail plate in vivo and in semithin sections labeled with bromodeoxyuridine, a marker for stem cells (neoblasts) in S-phase.     

Astroglial expression of the P-glycoprotein is controlled by intracellular CNTF

Background  

The P-glycoprotein (P-gp), an ATP binding cassette transmembrane transporter, is expressed by astrocytes in the adult brain, and is positively modulated during astrogliosis. In a search for factors involved in this modulation, P-gp overexpression was studied in long-term in vitro astroglial cultures.     

Patterning of mutually interacting bacterial bodies: close contacts and airborne signals

Background  

Bacterial bodies (colonies) can develop complex patterns of color and structure. These patterns may arise as a result of both colony-autonomous developmental and regulatory processes (self-patterning) and environmental influences, including those generated by neighbor bodies. We have studied the interplay of intra-colony signaling (self-patterning) and inter-colony influences in related clones of Serratia rubidaea grown on rich media.     

The molecular evolution of <Emphasis Type="Italic">PL10</Emphasis> homologs

Background  

PL10 homologs exist in a wide range of eukaryotes from yeast, plants to animals. They share a DEAD motif and belong to the DEAD-box polypeptide 3 (DDX3) subfamily with a major role in RNA metabolism. The lineage-specific expression patterns and various genomic structures and locations of PL10 homologs indicate these homologs have an interesting evolutionary history.     

Importance of replication in analyzing time-series gene expression data: Corticosteroid dynamics and circadian patterns in rat liver

Background  

Comprehensively understanding corticosteroid pharmacogenomic effects is an essential step towards an insight into the underlying molecular mechanisms for both beneficial and detrimental clinical effects. Nevertheless, even in a single tissue different methods of corticosteroid administration can induce different patterns of expression and regulatory control structures. Therefore, rich in vivo datasets of pharmacological time-series with two dosing regimens sampled from rat liver are examined for temporal patterns of changes in gene expression and their regulatory commonalities.     

Genomic expression dominance in allopolyploids

Background  

Allopolyploid speciation requires rapid evolutionary reconciliation of two diverged genomes and gene regulatory networks. Here we describe global patterns of gene expression accompanying genomic merger and doubling in inter-specific crosses in the cotton genus (Gossypium L.).     

Antibiotics resistance of Helicobacter pylori in children with upper gastrointestinal symptoms in Hangzhou,China

Background

The decreasing eradication rate of Helicobacter pylori is mainly because of the progressive increase in its resistance to antibiotics. Studies on antimicrobial susceptibility of H. pylori in children are limited. This study aimed to investigate the resistance rates and patterns of H. pylori strains isolated from children.

Materials and Methods

Gastric mucosa biopsy samples obtained from children who had undergone upper gastrointestinal endoscopy were cultured for H. pylori, and susceptibility to six antibiotics (clarithromycin, amoxicillin, gentamicin, furazolidone, metronidazole, and levofloxacin) was tested from 2012‐2014.

Results

A total of 545 H. pylori strains were isolated from 1390 children recruited. The total resistance rates of H. pylori to clarithromycin, metronidazole, and levofloxacin were 20.6%, 68.8%, and 9.0%, respectively. No resistance to amoxicillin, gentamicin, and furazolidone was detected. 56.1% strains were single resistance, 19.6% were resistant to more than one antibiotic, 16.7% for double resistance, and 2.9% for triple resistance in 413 strains against any antibiotic. And the H. pylori resistance rate increased significantly from 2012‐2014. There was no significant difference in the resistance rates to clarithromycin, metronidazole, and levofloxacin between different gender, age groups, and patients with peptic ulcer diseases or nonulcer diseases.

Conclusions

Antibiotic resistance was indicated in H. pylori strains isolated from children in Hangzhou, and it increased significantly during the 3 years. Our data strongly support current guidelines, which recommend antibiotic susceptibility tests prior to eradication therapy.     

Comparative phylogeography of two co‐distributed but ecologically distinct rainbowfishes of far‐northern Australia

Aim

To test the influence of historical and contemporary environment in shaping the genetic diversity of freshwater fauna we contrast genetic structure in two co‐distributed, but ecologically distinct, rainbowfish; a habitat generalist (Melanotaenia splendida) and a habitat specialist (M. trifasciata).

Location

Fishes were sampled from far northern Australia (Queensland and Northern Territory).

Methods

We used sequence data from one mitochondrial gene and one nuclear gene to investigate patterns of genetic diversity in M. splendida and M. trifasciata to determine how differences in habitat preference and historical changes in drainage boundaries affected patterns of connectivity.

Results

Melanotaenia splendida showed high levels of genetic diversity and little population structure across its range. In contrast, M. trifasciata showed high levels of population structure. Whereas phylogeographic patterns differed, both species showed a strong relationship between geographical distance and genetic differentiation between populations. Melanotaenia splendida showed a shallower relationship with geographical distance, and genetic differentiation was best explained by stream length and a lower scaled ocean distance (11.98 times coast length). For M. trifasciata, genetic differentiation was best explained by overwater distance between catchments and ocean distance scaled at 1.16 × 10⁶ times coast length.

Main conclusions

Connectivity of freshwater populations inhabiting regions periodically interconnected during glacial periods appears to have been affected by ecological differences between species. Species‐specific differences are epitomized here by the contrast between co‐distributed congeners with different habitat requirements: for the habitat generalist, M. splendida, there was evidence for greater historical genetic connectivity with oceans as a weaker barrier to gene exchange in contrast with the habitat specialist, M. trifasciata.