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Neutrophils are phagocytic leukocytes that represent one of the first lines of defense during infection. These cells are phagocytose and kills microbes through the production of toxins such as superoxide anions, hydrogen peroxide, and nitric oxide. The isolation of neutrophils from either human beings or animals, such as mice, is a common first step for researchers when investigating innate immunity to microbes. Fortunately, there are literature reports that compares the separation properties and functional responses of cells isolated from different animal species. However, researchers still encounter technical problems with regard to purification, viability, and recovery. In this study, we describe different methods for the isolation of neutrophils from mouse blood. We compared the purity, viability, yield, and the expression of immunological receptors and functional responses such as ROS production induced by opsonized particles of zymosan and phorbol 12-myristate 13-acetate-stimulated of neutrophils isolated in four procedures. In this comparative study, we observed that Percoll was most appropriate for the isolation of mouse neutrophils, because we obtained the most pure and viable cell preparation through this process. Neutrophils isolated with a Percoll gradient demonstrated a greater production of reactive oxygen and nitrogen species compared to the other techniques. Additionally, we observed a slight increase in the expression of CD64 when cells were purified with the gelatin method and over 95 % expression of the CD16 and CD32 receptors with all methods evaluated. [ABSTRACT FROM AUTHOR]

Biological traits and colony structure are difficult to analyze in subterranean termites owing to their cryptic lifestyle and their often elusive breeding system. However, the use of molecular markers in a population genetics framework allows the investigation of such aspects. We present here the colony genetic structures of 12 samples collected along the Italian peninsula of two Reticulitermes species (the native R. lucifugus and the introduced R. urbis) analyzed through nuclear microsatellite markers. Reproductive strategies and colony breeding systems differ between the two species. Secondary reproductives of R. lucifugus, collected in three colonies, are all females; genotyping comparisons between these females and their nest mate workers clearly indicate the presence of asexual queen succession (AQS) events in this species, as observed in the Japanese R. speratus and in the North-American R. virginicus. Two other R. lucifugus colonies have a mixed family genetic pattern, possibly as the result of colony fusion events: accordingly, relatedness estimates indicate the presence of genetically unrelated workers. On the contrary, all R. urbis colonies have a genetic structure compatible with the presence of multiple secondary reproductives, as expected on the basis of previous analyses. Moreover, neotenics' sex ratio is balanced and their heterozygosity is comparable to that of nest mate workers, suggesting that AQS is lacking in this taxon. The differences observed in such biological traits between the two species are discussed in the light of their invasive potential. [ABSTRACT FROM AUTHOR]

The R2 retrotransposon is here characterized in bisexual populations of the European crustacean Triops cancriformis. The isolated element matches well with the general aspects of the R2 family and it is highly differentiated from that of the congeneric North American Triops longicaudatus. The analysis of 5′ truncations indicates that R2 dynamics in T. cancriformis populations show a high turnover rate as observed in Drosophila simulans. For the first time in the literature, though, individuals harboring truncation variants, but lacking the complete element, are found. Present results suggest that transposition-mediated deletion mechanisms, possibly involving genomic turnover processes acting on rDNAs, can dramatically decrease the copy number or even delete R2 from the ribosomal locus. The presence of R2 does not seem to impact on the nucleotide variation of inserted 28S rDNA with respect to the uninserted genes. On the other hand, a low level of polymorphism characterizes rDNA units because new 28S variants continuously spread across the ribosomal array. Again, the interplay between transposition-mediated deletion and molecular drive may explain this pattern. [ABSTRACT FROM AUTHOR]

The ubiquity of satellite DNA (satDNA) sequences has raised much controversy over the abundance of divergent monomer variants and the long-time nucleotide sequence stability observed for many satDNA families. In this work, we describe the satDNA BIV160, characterized in nine species of the three main bivalve clades (Protobranchia, Pteriomorphia and Heteroconchia). BIV160 monomers are similar in repeat size and nucleotide sequence to satDNAs described earlier in oysters and in the clam Donax trunculus. The broad distribution of BIV160 satDNA indicates that similar variants existed in the ancestral bivalve species that lived about 540 million years ago; this makes BIV160 the most ancient satDNA described so far. In the species examined, monomer variants are distributed in quite a complex pattern. This pattern includes (i) species characterized by a specific group of variants, (ii) species that share distinct group(s) of variants and (iii) species with both specific and shared types. The evolutionary scenario suggested by these data reconciles sequence uniformity in homogenization-maintained satDNA arrays with the genomic richness of divergent monomer variants formed by diversification of the same ancestral satDNA sequence. Diversified repeats can continue to evolve in a non-concerted manner and behave as independent amplification-contraction units in the framework of a ‘library of satDNA variants’ representing a permanent source of monomers that can be amplified into novel homogeneous satDNA arrays. On the whole, diversification of satDNA monomers and copy number fluctuations provide a highly dynamic genomic environment able to form and displace satDNA sequence variants rapidly in evolution. [ABSTRACT FROM AUTHOR]

The living fossil Triops cancriformis comprises bisexual (either gonochoric or hermaphroditic) and unisexual populations. Genetic surveys have recently revealed a general trend of low differentiation of 12S and 16S mitochondrial genes. We, therefore, surveyed further mitochondrial (COI gene and control region) and nuclear markers (dinucleotide microsatellites) to assess the genetic variability and to establish any relationship with the different reproductive modes found in European populations. The mitochondrial analyses confirmed the pattern of low variability. Hence, the low mitochondrial genetic variability appears as a common feature of the genus Triops. The microsatellite analysis found that Italian populations are monomorphic or exhibit little polymorphism, while other European samples display a higher degree of polymorphism and private alleles. Spanish, Austrian and Italian populations show patterns of Hardy–Weinberg disequilibrium that could be explained by the mode of reproduction, or by a higher frequency of null alleles in these populations. The low diversity and differentiation among Italian populations lead us to question the Monopolization Hypothesis. One microsatellite locus appears to be sex-linked, with heterozygotes detected only in males and hermaphrodites.Heredity (2008) 100, 496–505; doi:10.1038/hdy.2008.3; published online 20 February 2008 [ABSTRACT FROM AUTHOR]

Randomly amplified polymorphic DNA (RAPD) was used to detect intra-clutch genetic differences of the anostracan Chirocephalus diaphanus Prévost, 1803. Thirty primers were tested on 130 nauplii from three different clutches. Two primers produced five repeatable and well-defined amplification products, that were used as genotype markers. Nauplii hatched after three successive dehydration and rehydration cycles. Consistent genetic differentiation was observed among nauplii from the same clutch. Significant association between presence or absence of three polymorphic amplification products and hatching after different stimuli was observed. These results suggest that RAPD markers might be related to the difference in nauplii hatching and provide reasonable support to the hypothesis that the source of the observed variation in hatching phenology are genetic as well as epigenetic. [ABSTRACT FROM AUTHOR]