Biological Time‐Dependent Difference in Effect of Peroxynitrite Demonstrated by the Mouse Hot Plate Pain Model

We previously demonstrated the rhythmic pattern of L‐arginine/nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) cascade in nociceptive processes. The coupled production of excess NO and superoxide leads to the formation of an unstable intermediate peroxynitrite, which is primarily responsible for NO‐mediated toxicity. In the present study, we evaluated the biological time‐dependent effects of exogenously administered peroxynitrite on nociceptive processes and peroxynitrite‐induced changes in the analgesic effect of morphine using the mouse hot‐plate pain model. Experiments were performed at four different times of day (1, 7, 13, and 19 hours after lights on, i.e., HALO) in mice of both sexes synchronized to a 12 h:12 h light‐dark cycle. Animals were injected intraperitoneally (i.p.) with saline or 10 mg/kg morphine 30 min before and 0.001 mg/kg peroxynitrite 30 sec before hot‐plate testing, respectively. The analgesic effect of morphine exhibited significant biological time‐dependent differences in the thermally‐induced algesia; whereas, administration of peroxynitrite alone exhibited either significant algesic or analgesic effect, depending on the circadian time of its injection. Concomitant administration of peroxynitrite and morphine reduced morphine‐induced analgesia at three of the four different study time points. In conclusion, peroxynitrite displayed nociceptive and antinociceptive when administered alone according to the circadian time of treatment, while it diminished analgesic activity when administered in combination with morphine at certain biological times.     

Seasonal Variation in Human Salivary Cortisol Concentration

Measurement of cortisol concentration can contribute important information about an individual's ability to adjust to various environmental demands of both physical and psychosocial origin. However, one uncertainty that affects the possibilities of correctly interpreting and designing field studies is the lack of observations of the impact of seasonal changes on cortisol excretion. For this reason, the month‐to‐month changes in diurnal cortisol concentration, the awakening cortisol response (ACR), maximum morning concentration, and fall during the day were studied in a group of 24 healthy men and women 32 to 61 yrs of age engaged in active work. On one workday for 12 consecutive months, participants collected saliva at four time points for determination of cortisol: at awakening, +30 min, +8 h, and at 21:00 h. Data were analyzed by a repeated measures design with month (12 levels) and time‐of‐day (4 levels) as categorical predictors. Cortisol concentrations were analyzed on a log scale. The diurnal pattern of cortisol was similar across months (interaction between month and time of day: p>0.4). The main effects of month and time‐of‐day were statistically significant (p <0.001). Highest concentrations were observed in February, March, and April, and lowest concentrations were observed in July and August. There were no statistically significant effects in any of the other measures, or between men and women. In conclusion, a seasonal variation in salivary cortisol concentrations was detected in an occupationally active population. Thus, seasonal variation needs to be taken into account when designing and evaluating field studies and interventions and when making comparisons across studies.     

Replication and discrimination of limb movement velocity

It is well known that proprioception is composed of the senses of movement and position. Whereas tests of position sense are quite commonly used, tests of the acuity in perception of movement velocity are scarce. In the present study we examined some novel tests for assessing the sense of limb movement velocity, involving replication and discrimination of single-joint movement velocity. Specifically, we investigated: (1) whether replication of limb movement velocity is more accurate following active criterion movements as compared to passive; (2) whether antagonist muscle contraction during passive limb movement enhances velocity discrimination; (3) how criterion movement velocity influences response accuracy; (4) the relationship between movement velocity and movement extent during velocity replication; and (5) whether subjects really base discrimination of velocities on perceived velocity. Sixteen healthy subjects participated in four tests (I-IV). For each test, horizontal abductions were performed about the right glenohumeral joint from the sagittal plane. The subjects were required to actively replicate the velocity of either an active (Test I) or passive (Test II) criterion movement, or judge whether a passive/semipassive (passive during antagonist muscle contraction) movement was faster or slower than a previous passive/semipassive criterion movement (Test III/IV). The results revealed higher response accuracy for Test I compared to Test II and for slower movements compared to faster, but no difference in response accuracy between Test III and IV. For velocity discrimination, the analysis revealed that the subjects based their judgment on the difference between criterion and comparison velocity rather than time or extent cues.     

Biometry of Cenomanian–Turonian placoliths: a proxy for changes of fertility and surface‐water temperature?

Most publications discussing Cenomanian–Turonian calcareous nannofossils focus on abundance fluctuations across the boundary interval. So far, there have been no studies that deal with the influence of palaeoenvironmental changes on the size of common Cenomanian–Turonian nannofossil taxa. The genera Biscutum, Broinsonia, Prediscosphaera, Retecapsa and Watznaueria have therefore been analysed from 19 samples of Cenomanian–Turonian age from the Goban Spur, northeast Atlantic. The genus Biscutum shows a slight decrease of mean length from 4.14 μm in the Cenomanian to 3.94 μm in the Turonian. Broinsonia is marked by a decrease from 6.07 μm in the Cenomanian to 5.64 μm in the Turonian. On the other hand, Prediscospheara increases in size from 4.98 μm in the Cenomanian to 5.61 μm in the Turonian. Two genera (Retecapsa, Watznaueria) show no significant changes in their mean length. The mean size of Biscutum is perhaps controlled by nutrients, where larger specimens may have preferred the more fertile palaeoenvironment of the Late Cenomanian. The size decrease of Biscutum in the Turonian is probably related to reduced nutrient availability. The genus Prediscosphaera spp., may have favoured low‐fertility conditions, as its mean size increases in the Turonian. A worldwide decline of the frequency of Broinsonia spp. during the Cenomanian–Turonian transition implies that this genus is not solely controlled by the nutrient content. The size of Broinsonia spp. may have been therefore influenced by the latest Cenomanian warming event. The increase in sea‐surface temperature may have been unfavourable for Broinsonia spp. as reflected by decreasing mean size and frequency. □Calcareous nannofossils, biometry, morphometry, Oceanic Anoxic Event 2.     

Phylogenetic analysis reveals that Rhabdopleura is an extant graptolite

A phylogenetic analysis of morphological data from modern pterobranch hemichordates (Cephalodiscus, Rhabdopleura) and representatives of each of the major graptolite orders reveals that Rhabdopleura nests among the benthic, encrusting graptolite taxa as it shares all of the synapomorphies that unite the graptolites. Therefore, rhabdopleurids can be regarded as extant members of the Subclass Graptolithina (Class Pterobranchia). Combined with the results of previous molecular phylogenetic studies of extant deuterostomes, these results also suggest that the Graptolithina is a sister taxon to the Subclass Cephalodiscida. The Graptolithina, as an important component of Early–Middle Palaeozoic biotas, provide data critical to our understanding of early deuterostome phylogeny. This result allows one to infer the zooid morphology, mechanics of colony growth and palaeobiology of fossil graptolites in direct relation to the living members of the clade. The Subdivision Graptoloida (nom. transl.), which are all planktic graptolites, is well supported in this analysis. In addition, we recognize the clade Eugraptolithina (nov.). This clade comprises the Graptoloida and all of the other common and well‐known graptolites of the distinctive Palaeozoic fauna. Most of the graptolites traditionally regarded as tuboids and dendroids appear to be paraphyletic groups within the Eugraptolithina; however, Epigraptus is probably not a member of this clade. The Eugraptolithina appear to be derived from an encrusting, Rhabdopleura‐like species, but the available information is insufficient to resolve the phylogeny of basal graptolites. The phylogenetic position of Mastigograptus and the status of the Dithecoidea and Mastigograptida also remain unresolved. □ Biodiversity, Cambrian, Hemichordata, Deuterostomia, Ordovician.     

Hydrogen peroxide pretreatment of roots enhanced oxidative stress response of tomato under cold stress

In the view of physiological role of H₂O₂, we investigated whether exogenous H₂O₂ application would affect short-term cold response of tomato and induce acclimation. Pretreatments were performed by immersing roots into 1 mM H₂O₂ solution for 1 h when transferring seedlings from seedling substrate to soil (acclimated group). Cold stress (3 °C for 16 h) caused significant reduction in relative water content (RWC) of control and non-acclimated (distilled water treated) groups when compared with unstressed plants. H₂O₂ promoted maintenance of relatively higher RWC under stress. Anthocyanin level in leaves of acclimated plants under cold stress was significantly higher than that of unstressed control and non-acclimated plants. Malondialdehyde (MDA) levels demonstrated low temperature induced oxidative damage to control and non-acclimated plants. MDA remained around unstressed conditions in acclimated plants, which demonstrate that H₂O₂ acclimation protected tissues against cold induced lipid peroxidation. H₂O₂ acclimation caused proline accumulation in roots under cold stress. Ascorbate peroxidase (APX) activity in roots of cold stressed and unstressed H₂O₂ acclimated plants increased when compared with control and non-acclimated plants, with highest increase in roots of acclimated plants under cold stress. CAT levels in roots of acclimated plants also increased, whereas levels remained unchanged in unstressed plants. Endogenous H₂O₂ levels significantly increased in roots of control and non-acclimated plants under cold stress. On the other hand, H₂O₂ content in roots of acclimated plants was significantly lower than control and non-acclimated plants under cold stress. The results presented here demonstrated that H₂O₂ significantly enhanced oxidative stress response by elevating the antioxidant status of tomato.     

A novel protein kinase involved in Na+ exclusion revealed from positional cloning

Salinity is a major abiotic stress which affects crop plants around the world, resulting in substantial loss of yield and millions of dollars of lost revenue. High levels of Na⁺ in shoot tissue have many adverse effects and, crucially, yield in cereals is commonly inversely proportional to the extent of shoot Na⁺ accumulation. We therefore need to identify genes, resistant plant cultivars and cellular processes that are involved in salinity tolerance, with the goal of introducing these factors into commercially available crops. Through the use of an Arabidopsis thaliana mapping population, we have identified a highly significant quantitative trait locus (QTL) linked to Na⁺ exclusion. Fine mapping of this QTL identified a protein kinase (AtCIPK16), related to AtSOS2, that was significantly up‐regulated under salt stress. Greater Na⁺ exclusion was associated with significantly higher root expression of AtCIPK16, which is due to differences in the gene's promoter. Constitutive overexpression of the gene in Arabidopsis leads to plants with significant reduction in shoot Na⁺ and greater salinity tolerance. amiRNA knock‐downs of AtCIPK16 in Arabidopsis show a negative correlation between the expression levels of the gene and the amount of shoot Na⁺. Transgenic barley lines overexpressing AtCIPK16 show increased salinity tolerance.     

Effects of a transient oxic period on mineralization of organic matter to CH4 and CO2 in anoxic peat incubations

Rates of organic matter mineralization in peatlands, and hence production of the greenhouse gases CH₄ and CO₂, are highly dependent on the distribution of oxygen in the peat. Using laboratory incubations of peat, we investigated the sensitivity of the anoxic production of CH₄ and CO₂ to a transient oxic period of a few weeks’ duration. Production rates during 3 successive anoxic periods were compared with rates in samples incubated in the presence of oxygen during the second period. In surface peat (5–10‐cm depth), with an initially high level of CH₄ production, oxic conditions during period 2 did not result in a lower potential CH₄ production rate during period 3, although production was delayed ～1 week. In permanently anoxic, deep peat (50–55‐cm depth) with a comparatively low initial production of CH₄, oxic conditions during period 2 resulted in zero production of CH₄ during period 3. Thus, the methanogens in surface peal—but not in deep peat—remained viable after several weeks of oxic conditions. In contrast to CH₄ production, the oxic period had a negligible effect on anoxic CO₂ production during period 3, in surface as well as deep peat. In both surface and deep peat, CO₂ production was several times higher under oxic than under anoxic conditions. However, for the first 2 weeks of oxic conditions, CO₂ production in the deep peat was very low. Still, deep peat obviously contained facultative microorganisms that, after a relatively short period, were able to maintain a considerably higher rate of organic matter mineralization under oxic than under anoxic conditions.     

Water mites of the genus Sperchon Kramer (Acari: Hydrachnidia: Sperchontidae) from Turkey,with description of a new species from Taurus Mountains (southern Turkey)

A new water mite species Sperchon (Hispidosperchon) serapae n. sp. is described. The material was collected from a slow-flowing stream during field study on the water mite fauna of the Lakes region in southwestern Turkey. An updated list of hitherto known species of Sperchon Kramer from Turkey, including nomenclatural changes and numerous new locality records to the species, is also given.     

Role of the Dinaric Karst (western Balkans) in shaping the phylogeographic structure of the threatened crayfish Austropotamobius torrentium

1. This study examines phylogeography and phylogeny of the threatened stone crayfish, Austropotamobius torrentium, in order to elucidate the role of the Dinaric Karst geology in shaping the evolutionary history and genetic diversity of aquatic fauna in the western Balkans. Mitochondrial 16S rRNA and COI genes were partially sequenced from 188 and 159 crayfish, respectively, sampled from 70 localities. Phylogenetic relationships were reconstructed using four methods of phylogenetic inference. Divergence times between phylogroups were estimated in a Bayesian framework, and their demographic history was examined using neutrality tests and mismatch distribution analysis. 2. Seven geographically localised phylogroups separated by pronounced genetic gaps were found. Five of them have a distribution range within the northern‐central Dinaric (NCD) region, while the remaining two include populations from the southern Balkans (SB) and central and south‐eastern Europe (CSE). The oldest divergence event separated two NCD lineages from the rest of populations in the Late Miocene or Early Pliocene. Divergences amongst the five NCD phylogroups and SB + CSE occurred in the Pliocene. The most recent split separated SB and CSE phylogroups during the Late Pliocene. For both genes, uncorrected pairwise divergences between most of the phylogroups (4.1–8.7% for COI and 1.6–4.8% for 16S rRNA) were of the same range as, or higher than, some of the interspecific distances previously reported for the genus Austropotamobius. 3. Geographically isolated and deeply divergent cryptic monophyletic phylogroups within A. torrentium in the NCD region arose in the course of intensification of Neotectonic movements during the Pliocene and the beginning of the Pleistocene and the development of karstification that has heavily fragmented the palaeohydrography of the area. The results confirm a gradual north–south expansion of stone crayfish during the pre‐Pleistocene that preceded the rapid northward post‐glacial re/colonisation of central Europe (CSE phylogroup) through the Danube drainage. 4. Austropotamobius torrentium comprises morphologically cryptic but molecularly distinct taxa. Considering the relatively small geographical areas they inhabit, the NCD phylogroups of stone crayfish should be given the highest conservation priority.