The oldest Devonian circumpolar ray-finned fish?

Actinopterygians (ray-finned fishes) are the most diverse group of living fishes, but have a sparse Devonian fossil record restricted to low palaeolatitudes. Here we report a new actinopterygian from the Paraná Basin of Brazil, which occupied a circumpolar position in the Palaeozoic. Available geological evidence supports a Middle Devonian or older age for this taxon, which shares features of the mandibular symphysis with the latest Devonian Tegeolepis. A phylogenetic analysis resolves these two as sister taxa. This new record expands the palaeogeographic distribution of Devonian ray-fins and suggests that gaps in their fossil record might be filled by exploring poorly sampled high-latitude localities within the Malvinokaffric Realm.     

Altered infant feeding patterns in boys with acquired nonsyndromic cryptorchidism

BACKGROUND : Genetic and environmental factors likely influence susceptibility to nonsyndromic cryptorchidism, a common disease presenting at birth or in later childhood. We compared cases and controls to define differential risk factors for congenital versus acquired cryptorchidism. METHODS : We compared questionnaire and clinical data from cases of congenital cryptorchidism (n = 230), acquired cryptorchidism (n = 182) and hernia/hydrocele (n = 104) with a group of healthy male controls (n = 358). Potential predictor variables (p < 0.2 in univariable analysis) were included in stepwise multivariable logistic regression models. RESULTS : Temporary (odds ratio [OR], 0.5; 95% confidence interval [CI], 0.4–0.8) or exclusive (OR, 0.6; 95% CI, 0.4–0.9) breastfeeding was reduced and soy formula feeding increased (OR, 1.8; 95% CI, 1.2–2.9) in acquired but not congenital or hernia/hydrocele groups. The highest risk estimates were observed for primary soy formula feeding with limited or no breastfeeding (OR 2.5; 95% CI, 1.4–4.3; adjusted OR, 2.7; 95% CI, 1.4–5.4) in the acquired group. Primary feeding risk estimates were equivalent or strengthened when multivariable models were limited to age greater than 2 years, full‐term or not small for gestational age, or Caucasian subjects. Pregnancy complications and increased maternal exposure to cosmetic or household chemicals were not consistently associated with either form of cryptorchidism in these models. CONCLUSIONS : Our data support reduced breastfeeding and soy formula feeding as potential risk factors for acquired cryptorchidism. Although additional studies are needed, hormonally active components of breast milk and soy formula could influence the establishment of normal testis position in the first months of life, leading to apparent ascent of testes in childhood. Birth Defects Research (Part A), 2012. © 2012 Wiley Periodicals, Inc.     

Denitrifying activity via nitrite and N2O production using acetate and swine wastewater

The presence of nitrite during denitrification is generally related to N₂O emissions. The aim of this work was to determine the operational conditions that have influences in the specific denitrifying activities (SDA) and N₂O production. Two factorial experimental designs (2³ and 2²) were performed to evaluate the effects of four operational variables (pH; biomass concentration; nitrite concentration and C/N ratio) on the SDA. Batch experiments were carried out with two different carbon sources: acetate and swine wastewater. Results showed that both biomass and NO₂^? concentrations had a significant effect on the SDA in the presence of acetate, in the case of swine slurry, pH also affected the SDA. N₂O production was only detected when swine wastewater was used and its specific production rate increased with the increase of the SDA. This result would indicate that N₂O emissions are also promoted when swine wastewater is treated in conditions that favor the SDA.     

Plasticity of DNA methylation in a nerve injury model of pain

The response of the peripheral nervous system (PNS) to injury may go together with alterations in epigenetics, a conjecture that has not been subjected to a comprehensive, genome-wide test. Using reduced representation bisulfite sequencing, we report widespread remodeling of DNA methylation in the rat dorsal root ganglion (DRG) occurring within 24 h of peripheral nerve ligation, a neuropathy model of allodynia. Significant (P < 10⁻⁴) cytosine hyper- and hypo-methylation was found at thousands of CpG sites. Remodeling occurred outside of CpG islands. Changes affected genes with known roles in the PNS, yet methylome remodeling also involved genes that were not linked to neuroplasticity by prior evidence. Consistent with emerging models relying on genome-wide methylation and RNA-seq analysis of promoter regions and gene bodies, variation of methylation was not tightly linked with variation of gene expression. Furthermore, approximately 44% of the dynamically changed CpGs were located outside of genes. We compared their positions with the intergenic, tissue-specific differentially methylated CpGs (tDMCs) of an independent experimental set consisting of liver, spleen, L4 control DRG, and muscle. Dynamic changes affected those intergenic CpGs that were different between tissues (P < 10⁻¹⁵) and almost never the invariant portion of the methylome (those CpGs that were identical across all tissues). Our findings—obtained in mixed tissue—show that peripheral nerve injury leads to methylome remodeling in the DRG. Future studies may address which of the cell types found in the DRG, such as specific groups of neurons or non-neuronal cells are affected by which aspect of the observed methylome remodeling.     

Effect of different calcium concentration on sperm motility and fertilisation capacity of rainbow trout (Oncorhynchus mykiss)

Calcium is a prerequisite factor for triggering the sperm activation in salmonids. The aim of this study was to test different concentrations of Ca²⁺ on sperm motility activation and fertility of rainbow trout (Oncorhynchus mykiss). Semen samples activated with calcium free activator (0.0 mM) and increasing concentrations of CaCl₂ (6.3, 7.9, 9.5 and 11 Mm) were evaluated by computer-assisted sperm analysis (CASA). To assess fertility, eggs from three females were fertilized with semen and activated with each of the five solutions and incubated until four-cell stage when the rate fertility and the symmetry of the first blastomeres were evaluated. The results show that eliminating calcium from the activator solution significantly reduced the motility rate and fertility in comparison with the other treatments, while increasing the CaCl₂ from 6.3 to 11 mM generated high sperm motility (78.5 ± 5.8–95.4 ± 4.0%) and fertility (85.0 ± 9.3–96.0 ± 6.51%) rates, and low symmetry rates in the first blastomeres (<20%). No significant differences were found between solutions for the latter two variables, suggesting that the calcium concentrations were in balance with the other components of the medium and within the requirements for the fertilization of rainbow trout.     

C4 genes of the chimpanzee,gorilla, and orang-utan: evidence for extensive homogenization

The human complement component 4 is encoded in two genes, C4A and C4B, residing between the class I and class II genes of the major histocompatibility complex. The C4A and C4B molecules differ in their biological activity, the former binding more efficiently to proteins than to carbohydrates while for the latter, the opposite holds true. To shed light on the origin of the C4 genes we isolated cosmid clones bearing the C4 genes of a chimpanzee, a gorilla, and an orang-utan. From the clones, we isolated the fragments coding for the C4d part of the gene (exons and introns) and sequenced them. Altogether we sequenced eight gene fragments: three chimpanzee (Patr-C4-1 ^*01, Patr-C4-1 ^*02, Patr-C4-2 ^*01), two gorilla (Gogo-C4-1 ^*01, Gogo-C4-2 ^*01), and three orang-utan (Popy-C4-1 ^*01, Popy-C4-2 ^*01, Popy-C4-3 ^*01). Comparison of the sequences with each other and with human C4 sequences revealed that in the region believed to be responsible for the functional difference between the C4A and C4B proteins the C4A genes of the different species fell into one group and the C4B genes fell into another. In the rest of the sequence, however, the C4A and C4B genes of each species resembled each other more than they did C4 genes of other species. These results are interpreted as suggesting extensive homogenization (concerted evolution) of the C4 genes in each species, most likely by repeated unequal, homologous, intragenic crossing-over. Address correspondence and offprint requests to: J. Klein.     

Salt stimulation of growth and photosynthesis in an extreme halophyte, Arthrocnemum macrostachyum

Halophytes that are capable of tolerating a wide range of salinity may grow best at intermediate salinities, but the physiological mechanisms underlying positive growth responses to salinity are not clear. This work investigated the growth of Arthrocnemum macrostachyum (Moric) C. Koch (a halophytic C3 shrub) over a wide range of salinities, and the extent to which its responses can be explained by photosynthetic physiology. Growth, gas exchange and chlorophyll fluorescence characteristics of plants were examined in a glasshouse experiment; tissue concentrations of photosynthetic pigments, ash, sodium, potassium, calcium and nitrogen were also determined. Plants showed marked stimulation of growth by salt, with a broad optimum of 171–510 m m NaCl for relative growth rate (RGR). Stimulation of RGR appeared to depend mainly on an increase in specific shoot area, whereas reduced RGR at high salinity (1030 m m ) could be attributed to a combination of lower unit shoot (leaf) rate and lower shoot mass fraction. The non-saline treatment plants had the greatest fraction of non-photosynthetic, atrophied surface area. However, net photosynthesis (A) was also stimulated by NaCl, with an optimum of c. 510 m m NaCl. The responses of A to salinity could be accounted for largely by limitation by stomatal conductance (Gs) and intercellular CO₂ concentration (Ci). Even the most hypersaline treatment apparently had no effect on photosystem II (PSII) function, and this resistance could be an important strategy for this halophyte in saline soils. In contrast, Fv/Fm indicated that absence of salt represents an environmental stress for A. macrostachyum and this could be a contributory factor to salt stimulation of A. Notwithstanding the importance of the ability to develop and maintain assimilatory surface area under saline conditions, stimulatory effects on A also appear to be part of a suite of halophytic adaptations in this plant.     

Different patterns of myometrial activity and 24-h rhythms in myometrial contractility in the gravid baboon during the second half of pregnancy.

Two clearly distinct epochs of myometrial contractility were observed in 13 pregnant baboons when recorded either as intraamniotic pressure (IAP) or myometrial electromyogram (EMG). Contractures, epochs lasting longer than 3 min, were the characteristic form of myometrial activity throughout pregnancy. Contractures generated only small increases in IAP. Short-lived contractions, generating larger increases in IAP, were characteristic of labor and delivery. Power spectral analysis of IAP and myometrial EMG activity proved to be an effective means whereby periods when the myometrium was in the contractures or contractions mode could be easily distinguished. Concomitantly recorded maternal intraabdominal temperature showed significant 24-h variations. When myometrial activity switched from low-amplitude, long-lasting regular contractures of pregnancy to contractions, the switch always occurred around the onset of darkness. Five baboons went into spontaneous labor, 3 prematurely and 2 at term. In these animals the switch from contractures to contractions occurred for several nights before delivery. The recurrence and timing of the switch from contractures to contractions for several nights before delivery were similar to the pattern we and others have observed in the pregnant rhesus monkey. The presence of 24-h periodicity in the patterns of specific types of myometrial activity in another nonhuman primate lends support to the view that similar 24-h patterns of myometrial activity may occur in pregnant women.