Structures and stability of N<Subscript>13</Subscript><Superscript>+</Superscript> and N<Subscript>13</Subscript><Superscript>−</Superscript> clusters

The structures and stabilities of eleven N₁₃ ⁺ and N₁₃ ^– isomers have been investigated with second-order Møller–Plesset (MP2) and density functional theory (DFT) methods. Five N₁₃ ⁺ isomers and six N₁₃ ^– isomers are all reasonable local minima on their potential energy hypersurfaces. The most stable N₁₃ ⁺ cation is structure C-2 with C_2v symmetry, which contains a pentazole ring and two N₄ open chains. It is different from those of the N₇ ⁺ and N₉ ⁺ clusters, but similar to the N₁₁ ⁺ cluster. Meanwhile, the most stable N₁₃ ^– structure A-2 is composed of a pentazole ring and a six-membered ring connected by two nitrogen atoms. It is not only different from those of the N₇ ^– and N₉ ^– clusters, but also from the N₁₁ ^– cluster. The decomposition pathways of structures C-2 and A-2 were investigated at the B3LYP/(aug)-cc-pVDZ level. From the barrier heights of the structures C-2 and A-2 decomposition processes, it is suggested that C-2 is difficult to observe experimentally and A-2 may be observed as a short-lived species. Figure Optimized geometrical parameters of N₁₃ ⁺ isomer C-2      

Biomining — biotechnologies for extracting and recovering metals from ores and waste materials

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Interactions between oestrogen and 1α,25(OH)<Subscript>2</Subscript>-vitamin D<Subscript>3</Subscript> signalling and their roles in spermatogenesis and spermatozoa functions

Oestrogens and 1α,25(OH)₂-vitamin D₃ (1,25-D₃) are steroids that can provide effects by binding to their receptors localised in the cytoplasm and in the nucleus or the plasma membrane respectively inducing genomic and non-genomic effects. As confirmed notably by invalidation of the genes, coding for their receptors as tested with mice with in vivo and in vitro treatments, oestrogens and 1,25-D₃ are regulators of spermatogenesis. Moreover, some functions of ejaculated spermatozoa as viability, DNA integrity, motility, capacitation, acrosome reaction and fertilizing ability are targets for these hormones. The studies conducted on their mechanisms of action, even though not completely elicited, have allowed the demonstration of putative interactions between their signalling pathways that are worth examining more closely. The present review focuses on the elements regulated by oestrogens and 1,25-D₃ in the testis and spermatozoa as well as the interactions between the signalling pathways of both hormones.     

α<Subscript>2A</Subscript>- and α<Subscript>2C</Subscript>-Adrenoceptors as Potential Targets for Dopamine and Dopamine Receptor Ligands

The poor norepinephrine innervation and high density of Gi/o-coupled α_2A- and α_2C-adrenoceptors in the striatum and the dense striatal dopamine innervation have prompted the possibility that dopamine could be an effective adrenoceptor ligand. Nevertheless, the reported adrenoceptor agonistic properties of dopamine are still inconclusive. In this study, we analyzed the binding of norepinephrine, dopamine, and several compounds reported as selective dopamine D₂-like receptor ligands, such as the D₃ receptor agonist 7-OH-PIPAT and the D₄ receptor agonist RO-105824, to α₂-adrenoceptors in cortical and striatal tissue, which express α_2A-adrenoceptors and both α_2A- and α_2C-adrenoceptors, respectively. The affinity of dopamine for α₂-adrenoceptors was found to be similar to that for D₁-like and D₂-like receptors. Moreover, the exogenous dopamine receptor ligands also showed high affinity for α_2A- and α_2C-adrenoceptors. Their ability to activate Gi/o proteins through α_2A- and α_2C-adrenoceptors was also analyzed in transfected cells with bioluminescent resonance energy transfer techniques. The relative ligand potencies and efficacies were dependent on the Gi/o protein subtype. Furthermore, dopamine binding to α₂-adrenoceptors was functional, inducing changes in dynamic mass redistribution, adenylyl cyclase activity, and ERK1/2 phosphorylation. Binding events were further studied with computer modeling of ligand docking. Docking of dopamine at α_2A- and α_2C-adrenoceptors was nearly identical to its binding to the crystallized D₃ receptor. Therefore, we provide conclusive evidence that α_2A- and α_2C-adrenoceptors are functional receptors for norepinephrine, dopamine, and other previously assumed selective D₂-like receptor ligands, which calls for revisiting previous studies with those ligands.     

Mitochondria and peroxisomes: Are the ‘Big Brother’ and the ‘Little Sister’ closer than assumed?

Mitochondria and peroxisomes are essential subcellular organelles in mammals. Despite obvious differences, both organelles display certain morphological and functional similarities. Recent studies have elucidated that these highly dynamic and plastic organelles share components of their division machinery. Mitochondria and peroxisomes are metabolically linked organelles, which are cooperating and cross-talking. This review addresses the dynamics and division of mitochondria and peroxisomes as well as their functional similarities to provide insight as to why these organelles share the fission machinery in evolutionary aspects.     

Electronic and optical properties of C<Subscript>24</Subscript>, C<Subscript>12</Subscript>X<Subscript>6</Subscript>Y<Subscript>6</Subscript>, and X<Subscript>12</Subscript>Y<Subscript>12</Subscript> (X = B,Al and Y = N,P)

Utilizing first-principles calculations, we studied the electronic and optical properties of C₂₄, C₁₂X₆Y₆, and X₁₂Y₁₂ fullerenes (X?=?B, Al; Y?=?N, P). These fullerenes are energetically stable, as demonstrated by their negative cohesive energies. The energy gap of C₂₄ may be tuned by doping, and the B₁₂N₁₂ fullerene was found to have the largest energy gap. All of the fullerenes had finite optical gaps, suggesting that they are optical semiconductors, and they strongly absorb UV radiation, so they could be used in UV light protection devices. They could also be used in solar cells and LEDs due to their low reflectivities.

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Graphical abstract Possible applications of doped C₂₄ fullerene

     

Genotype × region and genotype × production level interactions in Holstein cows

The identification of the presence of genotype by environment interaction effects on important traits in Holstein cattle allows for the use of international genetic evaluations and a more efficient design of regional genetic evaluation programmes. The aim of this study was to determine the genotype × environment interaction effects in Chilean Holstein dairy cattle through the analysis of records corresponding to calvings between 1998 and 2015. Herds were classified in the central and southern regions of Chile based on herd location as well as by high and low levels of production environments based on the fat plus protein yield averages per herd within each region. The central region has a Mediterranean climate and a confined production system while the southern region has a humid temperate climate and a production system based on grazing with supplementation. Traits studied were milk yield (MY), fat yield (FY), protein yield (PY), fat content (FC) and protein content (PC) by lactation, age at first calving (AFC) and calving interval (CI). Several four-trait mixed animal models were applied to environmental category data as different traits, which included herd-year-calving season (herd-year-birth season for AFC) and lactation number as fixed effects, and animal additive genetic, sire-herd, permanent environment and residual effects as random effects. Genetic correlations (r_g) for MY, FY, FC, PC and CI were found to decrease as differences between environmental categories increased. The r_g between the most extreme environmental categories considered in this study for AFC (0.26) was the only one found statistically lower than 0.60. Genetic correlation values statistically lower than 0.80 (P < 0.05) were observed for AFC, CI, MY, FY and PY between some environmental categories. If separate genetic evaluations are adopted as practical criteria when the value of r_g is lower than 0.60, the consequence of improving a multi-trait economic breeding objective in this population is likely to be small unless extreme environmental categories are considered. However, a moderate decrease in selection response and re-ranking of selection candidates is expected for AFC, CI and yield traits when selection is performed in different environmental conditions. Genotype × environment interaction effects involving production systems in a Mediterranean climate and confinement vs. Temperate Oceanic climate and grazing with supplementation, and between two fat plus protein yield level categories within each environment, were at most moderate for the studied traits.     

Transport of nitrogen and zinc to rhodes grass by arbuscular mycorrhiza and roots as affected by different nitrogen sources (NH<Subscript>4</Subscript><Superscript>+</Superscript>-N and NO<Subscript>3</Subscript><Superscript>−</Superscript>-N)

We investigated the effect of mineral nitrogen forms on transfer of nitrogen (N) and zinc (Zn) from attached compartments to rhodes grass (Chloris gayana) colonised with arbuscular mycorrhizal fungi (AMF). After being pre-cultivated in substrates with adequate nutrient supply and either AMF inoculated (+AM) or left non-inoculated (?AM), rhodes grass was positioned adjacent to an outer compartment holding a similar substrate but applied with labelled nitrogen (¹⁵N) either as ammonium (NH₄ ⁺) or nitrate (NO₃ ^?), and a high supply of Zn (150 mg kg^?1 DS). Plant roots together with fungal mycelium were either allowed to explore the outer compartment (with root access) or only mycorrhizal hyphae were allowed (without root access). Within each access treatment, biomasses of rhodes grass were not significantly affected by AMF inoculation or N form. AMF contribution to plant ¹⁵N uptake was about double in NH₄ ⁺ compared with NO₃ ^?-supplied treatments while the mycorrhizal influence on plant Zn uptake was insignificant. Without root access, the shoot ¹⁵N/Zn concentration ratio was up to ten-fold higher in +AM than –AM treatments and this ratio increase was clearly more pronounced in NH₄ ⁺ than NO₃ ^?-supplied treatments. In conclusion, rhodes grass in symbiosis with the tested AMF acquired more N when supplied with ammonium. Moreover, there is clear indication that although the AMF have transported both nutrients (N and Zn), N was preferentially transferred as compared to Zn. We confirmed that, while rhodes grass is not able to prevent excessive Zn uptake via roots under conditions of high Zn, mycorrhiza is able to avoid excessive Zn supply to the host plant when the fungus alone has access to contaminated patches.     

Middle pleistocene humans from africa

Patterns of human evolution in the Middle Pleistocene remain poorly understood. There is general consensus that by the onset of this time period, populations ofHomo erectus were dispersed from Africa into Eurasia, including the Far East. In the western part of this range (perhaps in Africa),Homo erectus then produced a daughter lineage exhibiting more advanced characters of the face, braincase and cranial base. How this new species should be defined is currently debated. In my view, fossils from sites such as Bodo and Broken Hill in Africa may be lumped with material from earlier Middle Pleistocene localities in Europe. Such a taxon is appropriately namedHomo heidelbergensis. Whether the hypodigm should be extended to include fossils from China is another question. In any case, this group of hominids is plausibly ancestral to both the specialized Neanderthals of Europe and more modern humans of the later Middle Pleistocene.     

The Casal de' Pazzi archaic parietal: comparative analysis of new fossil evidence from the late Middle Pleistocene of Rome

A fossilized fragment of human parietal bone has been recently recovered from the lowest layer of the Casal de' Pazzi fluvial deposit (stratigraphically dated at about 200–250 ky BP). The fossil presents characters-i.e., thickness, degree and development of curvature, type of endocranial vascularization-which distinguish it from the corresponding cranial regions of both Homo erectus and anatomically modern Homo sapiens. While a morphological orientation towards Neanderthal characters can be considered, the affinities of the Casal de' Pazzi parietal are primarily with other late Middle Pleistocene specimens. The authors conclude that the Casal de' Pazzi human find can be assigned to the “archaic Homo sapiens” group falling within the European pre-Neanderthal range. Its particular morphology constitutes new evidence of human evolution from the geographical area of Rome.     

Brain size at birth throughout human evolution: a new method for estimating neonatal brain size in hominins

An increase in brain size is a hallmark of human evolution. Questions regarding the evolution of brain development and obstetric constraints in the human lineage can be addressed with accurate estimates of the size of the brain at birth in hominins. Previous estimates of brain size at birth in fossil hominins have been calculated from regressions of neonatal body or brain mass to adult body mass, but this approach is problematic for two reasons: modern humans are outliers for these regressions, and hominin adult body masses are difficult to estimate. To accurately estimate the brain size at birth in extinct human ancestors, an equation is needed for which modern humans fit the anthropoid regression and one in which the hominin variable entered into the regression equation has limited error. Using phylogenetically sensitive statistics, a resampling approach, and brain-mass data from the literature and from National Primate Research Centers on 362 neonates and 2802 adults from eight different anthropoid species, we found that the size of the adult brain can strongly predict the size of the neonatal brain (r² = 0.97). This regression predicts human brain size, indicating that humans have precisely the brain size expected as an adult given the size of the brain at birth. We estimated the size of the neonatal brain in fossil hominins from a reduced major axis regression equation using published cranial capacities of 89 adult fossil crania. We suggest that australopiths gave birth to infants with cranial capacities that were on average 180 cc (95% CI: 158–205 cc), slightly larger than the average neonatal brain size of chimpanzees. Neonatal brain size increased in early Homo to 225 cc (95% CI: 198–257 cc) and in Homo erectus to approximately 270 cc (95% CI: 237–310 cc). These results have implications for interpreting the evolution of the birth process and brain development in all hominins from the australopiths and early Homo, through H. erectus, to Homo sapiens.     

Dental microwear texture analysis and diet in the Dmanisi hominins

Reconstructions of foraging behavior and diet are central to our understanding of fossil hominin ecology and evolution. Current hypotheses for the evolution of the genus Homo invoke a change in foraging behavior to include higher quality foods. Recent microwear texture analyses of fossil hominin teeth have suggested that the evolution of Homo erectus may have been marked by a transition to a more variable diet. In this study, we used microwear texture analysis to examine the occlusal surface of 2 molars from Dmanisi, a 1.8 million year old fossil hominin site in the Republic of Georgia. The Dmanisi molars were characterized by a moderate degree of surface complexity (Asfc), low textural fill volume (Tfv), and a relatively low scale of maximum complexity (Smc), similar to specimens of early African H. erectus. While caution must be used in drawing conclusions from this small sample (n = 2), these results are consistent with continuity in diet as H. erectus expanded into Eurasia.     

Candidatus Monilibacter spp., common bulking filaments in activated sludge, are members of Cluster III Defluviicoccus

Two alphaproteobacterial Neisser negative ‘Nostocoida limicola’ morphotypes differing slightly in their trichome diameter and filament regularity were dominant populations in the Bendigo, Victoria, Australia activated sludge community removing phosphorus (P). Neither responded to the FISH probes available for any of the other alphaproteobacterial ‘N. limicola’ morphotypes. Instead both fluoresced with the DF988 FISH probe designed originally to target alphaproteobacterial cluster II Defluviicoccus tetrad forming organisms. A 16S rRNA based clone library from this biomass revealed that the alphaproteobacterial clones grouped closely with Candidatus ‘Monilibacter batavus’ and Defluviicoccus clones in a cluster separate from the existing cluster I and II Defluviicoccus. When a FISH probe was designed against these, it only hybridized to the thinner and less abundant ‘N. limicola’ morphotype. Micromanipulation–RT-PCR was used to selectively recover the main ‘N. limicola’ morphotype and a FISH probe designed against the 16S rRNA clones generated from it showed only this filament fluoresced. From FISH based surveys, both ‘N. limicola’ variants occurred frequently in phosphorus removal activated sludge systems in Australia treating domestic waste. The data suggest that they represent two new strains of Candidatus ‘Monilibacter’, which on this evidence are filamentous members of the genus Defluviicoccus, a potential competitor for the polyphosphate accumulating organisms in these communities.     

Bee brood consumption: an alternative explanation for hypervitaminosis A in KNM-ER 1808 (Homo erectus) from Koobi Fora, Kenya

AHomo erectus individual (KNM-ER 1808) from Koobi Fora, Kenya dating from 1·6 ± 0·1 million years exhibits pathological apposition of bone on long bone shafts. This was originally attributed to hypervitaminosis A from the consumption of carnivore livers. Bee brood has a sufficiently high concentration of vitamin A that protracted ingestion could theoretically produce hypervitaminosis A. The ecology of the East African bee,Apis mellifera scutelatta, is investigated to show that the density of nests with their brood contents within a reasonable foraging area of earlyHomo erectus would yield an ample and reliable energy source with deleteriously high vitamin A content. A potential role of honey gathering and insect larvae consumption in hominine behavioural and physical evolution is discussed.     

A newHomo erectus cranium from Sangiran, Java

A newHomo erectus cranium was found on May 18, 1993 by Budi, a local farmer, at Sangiran. It dates from the Middle Pucangan Formation approximately 1.6–1.8 mya. The braincase is essentially complete and as is most of the face. The vault has the typicalH. erectus gable shape. There is a clear sagittal ridge beginning below the middle of the frontal squama and running to mid-parietal. Parasagittal ridges are rounded angulations halfway up the parietals, and coincide with poorly marked temporal lines. In all measurements, this skull is longer and consistently narrower than Trinil. It is chronologically and morphologically similar to the famousH. erectus skull from east Africa, KNMER-3733. Although existing much older, this new specimen is what one would expect a female counterpart to Sangiran 17 to look like.     

Combined mitochondrial and nuclear data enhance resolution of a rapid radiation of Australian rainbow skinks (Scincidae: Carlia)

In contrast to low diversity seen in many Australian rainforest squamate genera, sclerophyll adapted groups—such as Carlia—show signs of faster diversification. Here we expand upon a previous single-locus mitochondrial DNA phylogenetic study of Carlia which described a major polytomy at an intermediate level of divergence. With additional mtDNA data, two nuclear intron loci and comprehensive taxonomic coverage, we provide support, congruent across loci, for the existence of three major clades. In doing so we recognise three genera for the ‘Carlia group of skinks’: clade 1, Carlia Gray, 1845; 2, Lygisaurus De Vis, 1884 (includes all species formerly known as Lygisaurus, and also includes C. parrhasius); 3, Liburnascincus Wells and Wellington, 1984 (consisting of three boulder-dwelling species). Remaining regions of low bootstrap and posterior probability support are associated with short internodes and apparent conflict among loci, as inferred by Partition Branch Support. Likelihood-based diversification-rate analysis rejects constant rate models, and indicates that Carlia underwent a period of relatively rapid diversification early in the evolution of the group, a rate 3–4 times faster than subsequent rates, and faster than comparable wet forest skinks.     

Fifty years vegetation development of a xerothermic calcareous grassland in Central Europe after heavy disturbance

Fifty years ago on the south-facing slope of a limestone hill 4 km NE of Göttingen (Germany) a small plot of 4 m² size was chosen in a xerothermic calcareous grassland (Mesobromion alliance) for investigation. The formerly grazed slope was abandoned a few years prior to the study, but in 1987 intermittent grazing started again. The mean annual temperature in Göttingen (1953–2003) was 8.8 °C on the average; the annual mean increased by 1.1 °C during the study period. Mean annual precipitation amounted to 642 mm (393–1093 mm). The mean monthly precipitation during summer (April–August) varied in the range between 29 and 101 mm. In the years 1953–2003 the presence of species was recorded annually in 400 subplots (100 cm² each). In part of this time also the amount of bare soil within the plot was recorded, and standing crop and the nitrogen contents in leaves of Bromus erectus were measured in the immediate surrounding of the plot.In fall 1953 the vegetation was removed completely in half of the plot, in the other half the two dominant grasses Bromus erectus and Brachypodium pinnatum were left. The differences between the two halves vanished already after 2 years (starting phase 1953–1955). Thus, only results concerning the plot as a whole are reported here. During the investigation three periods could be distinguished. After the starting phase in period I (1955–1986) total presence, presence of the most important species, species richness, number of endangered species, diversity and evenness increased. In this way the grassland regenerated after the heavy disturbance, and a dense, species-rich vegetation formed. Only a few species showed maximum values already within the first 10 years and faded out later.Period II (1987–1997) spanned 10 years of grazing. During this time total presence, presence of many important species, species richness, number of endangered species, diversity and evenness decreased, whereas areas with bare soil increased. Only two species showed maximum values during this phase, and just one new species invaded (Lolium perenne). During this period a more open type of grassland was formed. Period III (1998–2003) spanned 5 years without grazing and only one grazing year (2002). Here, a partial regeneration of a more closed grassland took place with traits similar to period I.Several phenomena occurred continuously through all three periods. Bromus erectus always was the dominating species. Nevertheless, proportions of graminoids (in % total presence) were lowered, and the proportion of herbs increased. The ratio Bromus erectus/Brachypodium pinnatum was determined mainly by Brachypodium. Seedlings of woody plants were always present, but in most cases survived only one summer. Shrubs did not settle inside the plot, although small bushes developed in the immediate surrounding. In summary the 50-year process can be described as a slow recovery of a calcareous grassland after very heavy disturbance, modified by intermittent grazing, without formation of shrub vegetation.     

“Meganthropus” cranial fossils from Java

There are now twelve significant hominid cranial fossils from the Lower and Middle Pleistocene of Java, all but two being from the Sangiran site. Most of this material is well-known in the literature, but three skulls, possibly representing “Meganthropus” are here described in detail for the first time. Most scholars have assigned them all toHomo erectus, while others have suggested that they represent as many as four different hominoid taxa. The author argues that they represent two possible species of hominids. “Meganthropus” I, II, and III are more massive than any of the knownH. erectus specimens. They are also relatively higher vaulted, apparently smaller brained, and have unusually thick lower occipital planes. “Meganthropus” may represent a species that separated fromH. erectus upon its arrival to Java.