血卟啉单甲醚介导的声动力疗法对牙龈卟啉单胞菌生物膜中丙二醛含量的影响

目的:探讨血卟啉单甲醚(hematoporphyrin monomethyl ether,HMME)介导的声动力疗法(sonodynamic therapy,SDT)对牙龈卟啉单胞菌(Porphyromonas gingivalis,Pg)生物膜中脂质过氧化物丙二醛(malondialdehyde,MDA)含量的影响。方法:羟基磷灰石片培养Pg生物膜厌氧培养3天,将生物膜随机分为4组(对照组、HMME组、超声组、SDT组),分别与无菌生理盐水或HMME进行避光孵育,然后进行声动力处理。采用平板计数法计算细菌存活率,MDA含量使用MDA检测试剂盒在可见光分光光度计下进行检测。结果:当超声强度为3 W/cm~2,超声时间为5 min时,SDT组的生物膜细菌存活率仅为40%,与对照组相比显著降低(P0.05),超声组细菌存活率为62%,与对照组相比亦显著降低(P0.05)。相同超声参数下,SDT组Pg生物膜中MDA含量最高,达17.3±1.2 nmol/mL(P0.05),超声组生物膜中MDA含量为7±0.8 nmol/mL,与对照组相比差异并无统计学意义(P0.05)。结论:HMME介导的SDT对Pg生物膜有一定杀伤效果,并且在杀伤过程中,可引发脂质过氧化反应,导致MDA释放。     

Immunomodulation of carcinogens-induced steroids-dependent human diseases

The experimental and clinical data about antibodies against environmental chemical carcinogens and endogenous steroids are represented. The conception of immunomodulation of carcinogens- and steroids-dependent human diseases is proposed. It is postulated that antibodies to polycyclic aromatic hydrocarbons and heterocyclic amines in cooperation with antibodies to cholesterol, sex hormones, mineralo- and glucocorticoids stimulate or inhibit cancer, malformation, cardiovascular and autoimmune diseases depending on their personal combination. It is recommended to use immunoassay of these antibodies for the human diseases prediction. The alternative approaches for prevention using the probiotics transformed by anti-carcinogen antibodies are substantiated.     

Enhanced plasminogen activation by staphylokinase in the presence of streptokinase beta/betagamma domains: plasminogen kringles play a role

Presence of isolated beta or betagamma domains of streptokinase (SK) increased the catalytic activity of staphylokinase (SAK)-plasmin (Pm) complex up to 60%. In contrast, fusion of SK beta or betagamma domains with the C-terminal end of SAK drastically reduced the catalytic activity of the activator complex. The enhancement effect mediated by beta or betagamma domain on Pg activator activity of SAK-Pm complex was reduced greatly (45%) in the presence of isolated kringles of Pg, whereas, kringles did not change cofactor activity of SAK fusion proteins (carrying beta or betagamma domains) significantly. When catalytic activity of SAK-microPm (catalytic domain of Pm lacking kringle domains) complex was examined in the presence of isolated beta and betagamma domains, no enhancement effect on Pg activation was observed, whereas, enzyme complex formed between microplasmin and SAK fusion proteins (SAKbeta and SAKbetagamma) displayed 50-70% reduction in their catalytic activity. The present study, thus, suggests that the exogenously present beta and betagamma interact with Pg/Pm via kringle domains and elevate catalytic activity of SAK-Pm activator complex resulting in enhanced substrate Pg activation. Fusion of beta or betagamma domains with SAK might alter these intermolecular interactions resulting in attenuated functional activity of SAK.     

Five hundred million years of extinction and recovery: a phanerozoic survey of large‐scale diversity patterns in fishes

Abstract: Fishes include more than half of all living animals with backbones, but large‐scale palaeobiological patterns in this assemblage have not received the same attention as those for terrestrial vertebrates. Previous surveys of the fish record have generally been anecdotal, or limited either in their stratigraphic or in their taxonomic scope. Here, we provide a broad overview of the Phanerozoic history of fish diversity, placing a special emphasis on intervals of turnover, evolutionary radiation, and extinction. In particular, we provide in‐depth reviews of changes during, and ecological and evolutionary recovery after, the end‐Devonian (Hangenberg) and Cretaceous–Palaeogene (K–Pg) extinctions.     

Gradualistic characean lineages in the Upper Cretaceous–Palaeocene of southern Europe

Two charophyte lineages from the Upper Cretaceous–Palaeocene of southern Europe are described here, constituting a useful biostratigraphic tool for correlating non-marine stratigraphic sequences. The Peckichara pectinata lineage, ranging from the middle Campanian to the middle–upper Maastrichtian, consists of four successive gyrogonite morphotypes that displayed progressively more complex gyrogonite ornamentation and increasingly smaller gyrogonites with time. The Peckichara sertulata lineage, ranging from the middle Campanian to the Danian, consists of three morphotypes that followed a more common evolutionary trend, developing progressively larger gyrogonites without any changes in ornamentation. Intermediate forms between the successive morphotypes suggest that they corresponded to anagenetic varieties of the same evolutionary species rather than to separate species. The different trends observed appear to be palaeoenvironmentally controlled. The grades of the P. pectinata lineage first occurred in permanent lakes that later shifted to fluvial influenced floodplain ponds, this shift accounting for the reduction in gyrogonite size. By contrast, the P. sertulata lineage mainly occurred in permanent lakes, where stable palaeoenvironmental conditions enabled a steady rise in gyrogonite size to increase the space available for the zygote.     

Crystal structure and thermal characterization of cadmium oxalate [CdC2O4 · 3H2O] and barium-doped cadmium oxalate [Ba0.5Cd0.5(C2O4)2 · 5H2O] single crystals grown in silica gel

Pure cadmium oxalate trihydrate (COT) and barium added cadmium oxalate (BCO) single crystals were grown by controlled diffusion of Cd²⁺ and Ba²⁺ ions in silica gel at ambient temperature. A single test tube technique coupled with gel aging conferred maximum size crystals by controlling the nucleation rate. It was found that the pH and age of the gel greatly influenced the crystal quality, their size and transparency. Grown crystals CdC₂O₄ · 3H₂O and Ba_0.5Cd_0.5(C₂O₄)₂ · 5H₂O were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and thermal analysis. Effect of barium dopant on the growth and morphology of cadmium oxalate was studied. Pure cadmium oxalate crystallized in triclinic system and the barium-doped cadmium oxalate crystallized in hexagonal system with massive changes in their unit cell parameters. The infrared spectrum revealed the presence of oxalate ligands and water of hydration in both the pure and barium-doped crystals. Thermal analysis showed that the grown crystals were dehydrated thermally even from lower temperatures and the doped crystals were found more stable.     

Ancient dates or accelerated rates? Morphological clocks and the antiquity of placental mammals

Analyses of a comprehensive morphological character matrix of mammals using ‘relaxed’ clock models (which simultaneously estimate topology, divergence dates and evolutionary rates), either alone or in combination with an 8.5 kb nuclear sequence dataset, retrieve implausibly ancient, Late Jurassic–Early Cretaceous estimates for the initial diversification of Placentalia (crown-group Eutheria). These dates are much older than all recent molecular and palaeontological estimates. They are recovered using two very different clock models, and regardless of whether the tree topology is freely estimated or constrained using scaffolds to match the current consensus placental phylogeny. This raises the possibility that divergence dates have been overestimated in previous analyses that have applied such clock models to morphological and total evidence datasets. Enforcing additional age constraints on selected internal divergences results in only a slight reduction of the age of Placentalia. Constraining Placentalia to less than 93.8 Ma, congruent with recent molecular estimates, does not require major changes in morphological or molecular evolutionary rates. Even constraining Placentalia to less than 66 Ma to match the ‘explosive’ palaeontological model results in only a 10- to 20-fold increase in maximum evolutionary rate for morphology, and fivefold for molecules. The large discrepancies between clock- and fossil-based estimates for divergence dates might therefore be attributable to relatively small changes in evolutionary rates through time, although other explanations (such as overly simplistic models of morphological evolution) need to be investigated. Conversely, dates inferred using relaxed clock models (especially with discrete morphological data and MrBayes) should be treated cautiously, as relatively minor deviations in rate patterns can generate large effects on estimated divergence dates.     

Integrated biostratigraphy based on planktonic foraminifera and dinoflagellates across the Cretaceous/Paleogene (K/Pg) transition at the Izeh section (SW Iran)

The present work is based on semi-quantitative study carried on detailed sampling (samples are spaced by 5, 10 and 15 cm close to the boundary) of an essentially continuous and expanded section crossing the Cretaceous–Paleogene (K/Pg) boundary in Iran. By this work, we attempt to detail biostratigraphy based on planktonic foraminifera biozones and correlate biozones and subzones with dinocyst events. The entire Cretaceous–Paleogene interval contains rich, diversified and well-preserved planktonic foraminifera and dinoflagellate cyst assemblages. Four planktonic foraminiferal biozones have been recognized across the Cretaceous–Paleogene transition (K/Pg): Abathomphalus mayaroensis Biozone including Plummerita hantkeninoides Subzone from the Late Maastrichtian and Guembelitria cretacea (including Hedbergella holmdelensis and Parvularugoglobigerina longiapertura subzones), Parvularugoglobigerina eugubina Biozone and Parasubbotina pseudobulloides Biozone belonging to the Early Danian. These biozones have been correlated with four dinocyst biozones: the Manumiella seelandica Biozone belonging to the Late Maastrichtian and the Alisocysta reticulata, Senoniasphaera inornata and Damassadinium californicum biozones from the Early Danian. At this section, like at the El Kef section (GSSP for the K/Pg) and the auxiliary sections, an Ir anomaly is detected indicating the K/Pg boundary. This geochemical anomaly coincides also with mass extinctions of planktonic foraminifera species. The extinct species are in particular the large, complex tropical and subtropical taxa dwelling in subsurface and lower photic water. The mass extinctions at the Izeh section occurred over a succinct period of time similar to the K/Pg type section at El Kef (Tunisia). These sudden mass extinctions indicate a catastrophic pattern event occurring at the Maastrichtian/Danian boundary. In contrast the organic-walled dinocysts were less affected by the mass extinction and most species crossed the K/Pg boundary without showing mass and sudden extinctions. Nevertheless, they showed changes in their assemblages’ structure beyond the K/Pg boundary. Especially, Manumiella seelandica and M. druggii, typical species of Antarctic Maastrichtian dinocysts assemblages, occur in coeval deposits at the Izeh section; they persist through the Lower Danian and, like in Tunisia (e.g., El Kef section, Ellès section) show an obvious increase in relative abundance.