Topological conflicts in phylogenetic analysis of different regions of the sable ( Martes zibellina L.) mitochondrial genome

Phylogenetic analysis of different regions of the mitochondrial genome of the sable showed the presence of several topologies of phylogenetic trees, but the most statistically significant topology is A-BC, which was obtained as a result of the analysis of the mitochondrial genome as a whole, as well as of the individual CO1, ND4, and ND5 genes. Analysis of the intergroup divergence of the mtDNA haplotypes (D xy) indicated that the maximum D xy values between A and BC groups were accompanied by minimum differences between B and C groups only for six genes showing the A-BC topology (12S rRNA, CO1, CO2, ND4, ND5, and CYTB). It is assumed that the topological conflicts observed in the analysis of individual sable mtDNA genes are associated with the uneven distribution of mutations along the mitochondrial genome and the mitochondrial tree. This may be due to random causes, as well as the nonuniform effect of selection.     

Metabolomics reveals herbivore‐induced metabolites of resistance and susceptibility in maize leaves and roots

Plants respond to herbivory by reprogramming their metabolism. Most research in this context has focused on locally induced compounds that function as toxins or feeding deterrents. We developed an ultra‐high‐pressure liquid chromatography time‐of‐flight mass spectrometry (UHPLC‐TOF‐MS)‐based metabolomics approach to evaluate local and systemic herbivore‐induced changes in maize leaves, sap, roots and root exudates without any prior assumptions about their function. Thirty‐two differentially regulated compounds were identified from Spodoptera littoralis‐infested maize seedlings and isolated for structure assignment by microflow nuclear magnetic resonance (CapNMR). Nine compounds were quantified by a high throughput direct nano‐infusion tandem mass spectrometry/mass spectrometry (MS/MS) method. Leaf infestation led to a marked local increase of 1,3‐benzoxazin‐4‐ones, phospholipids, N‐hydroxycinnamoyltyramines, azealic acid and tryptophan. Only few changes were found in the root metabolome, but 1,3‐benzoxazin‐4‐ones increased in the vascular sap and root exudates. The role of N‐hydroxycinnamoyltyramines in plant–herbivore interactions is unknown, and we therefore tested the effect of the dominating p‐coumaroyltyramine on S. littoralis. Unexpectedly, p‐coumaroyltyramine was metabolized by the larvae and increased larval growth, possibly by providing additional nitrogen to the insect. Taken together, this study illustrates that herbivore attack leads to the induction of metabolites that can have contrasting effects on herbivore resistance in the leaves and roots.     

聚酸酐控释制剂的研究进展

聚酸酐材料是一种良好的生物可降解材料,它可以作为药物载体将药物递送入人体的各个器官,如脑、骨骼、血管等,也可作为基因的载体对患者进行基因治疗。聚酸酐的合成工艺简单、成本低廉,可以满足不同的用途。它奇在人体内降解为对人体无害的二元酸而排除体内,具有良好的生物相容性。文中综述了聚酸酐的合成,聚酸酐控释制剂的制备工艺、降解、体内安全性和临床应用方面的研究进展,并提出了今后的发展方向。聚酸酐在医学方面的研究和应用必将日益广泛。     

Radiation diagnosis for tuberculous gonitis in children

Tuberculous knee joint lesion in children is the most common form of articular pathology. The high sociomedical significance of this disease in modern society is determined by not only its prevalence, but also economic losses caused by high disability rates in children. The purpose of the study was to determine the possibilities and place of a comprehensive radiation study in the diagnosis of tuberculous gonitis in children. Sixty patients aged 10 months to 18 years were examined. Clinical studies were comprehensively assessed, by taking into account the collected history data and orhthopedic and laboratory findings. Surgery was made in 26 children. All the patients underwent mutiprojection X-ray study, knee joint ultrasound study being made in 48 patients. Knee joint X-ray study was performed on Siregraph (Siemens) apparatuses. Real-time ultrasonography was conducted on Aloka SSD-1100 and Aloka--3500+ apparatuses, by employing a 7.5-MHz linear transducer. According to P.G. Kornev (1971), three phases were identified in the course of tuberculous gonitis. These included prearthritic (the development of primary ostitis); arthritic (articular cartilage destruction, followed by the development of secondary arthritis; and postarthritic (sequels of prior tuberculous osteomyelitis) phases. Analysis indicated that the use of the routine X-ray study in combination with ultrasound scanning in the diagnosis of tuberculous gonitis in children yielded more adequate information on tissue and knee joint structural changes and made it possible to define further policy treatment and to predict the outcomes of the disease.     

Fungi associated with rice at entre rios province, Argentina. toxigenic capacity offusarium graminearum andmicrodochium nivale isolates

A mycological survey was carried out on rice samples harvested in 1997 and 1998 from Entre Ríos province, belonging to the main production area of Argentina. The relative density and isolation frequency of the prevalent fungi were statistically compared between locations and harvest seasons. The genusAlternaria was the most prevalent component of the internal seedborne mycoflora in the two harvest seasons. Fungi belonging to the generaPhoma, Fusarium, Microdochium, Penicillium andAspergillus were also isolated. The predominant species of these genera wereAlternaria alternata, Phoma glomerata, Fusarium graminearum, Microdochium nivale, Penicillium citrinum and Aspergillus flavus.     

Climate change hastens the turnover of stream fish assemblages

Stream fish are expected to be significantly influenced by climate change, as they are ectothermic animals whose dispersal is limited within hydrographic networks. Nonetheless, they are also controlled by other physical factors that may prevent them moving to new thermally suitable sites. Using presence–absence records in 655 sites widespread throughout nine French river units, we predicted the potential future distribution of 30 common stream fish species facing temperature warming and change in precipitation regime. We also assessed the potential impacts on fish assemblages' structure and diversity. Only cold-water species, whose diversity is very low in French streams, were predicted to experience a strong reduction in the number of suitable sites. In contrast, most cool-water and warm-water fish species were projected to colonize many newly suitable sites. Considering that cold headwater streams are the most numerous on the Earth's surface, our results suggested that headwater species would undergo a deleterious effect of climate change, whereas downstream species would expand their range by migrating to sites located in intermediate streams or upstream. As a result, local species richness was forecasted to increase greatly and high turnover rates indicated future fundamental changes in assemblages' structure. Changes in assemblage composition were also positively related to the intensity of warming. Overall, these results (1) stressed the importance of accounting for both climatic and topographic factors when assessing the future distribution of riverine fish species and (2) may be viewed as a first estimation of climate change impacts on European freshwater fish assemblages.     

Lead-phase and red-stripe color morphs of red-backed salamanders Plethodon cinereus differ in hematological stress indices: A consequence of differential predation pressure?

Throughout the animal kingdom there are species that have two or more phenotypic forms or 'morphs', and many of these are amphibians. In North America, the red-backed salamander Plethodon cinereus can have either a red dorsal stripe or no dorsal stripe (lead-phase form), and evidence to date indicates the lead-phase form incurs a greater number of attacks from predators. In a recent collection of 51 P. Cinereus, blood smears of both color morphs (35 red-stripe, 16 lead-phase) were examined to obtain numbers of circulating leukocytes (via light microscopy), which can be used to indirectly estimate levels of stress hormones in vertebrates via a 'hematological stress index', which is the ratio between the number of two leukocyte types (neutrophils and lymphoeytes). Our results showed that lead-phase salamanders tended to have greater numbers of circulating neutrophils and lower numbers of circulating iymphocytes than red-stripe morphs, leading to higher average neutrophil-lymphocyte ratios in lead-phase individuals. Since the salamanders were held (refrigerated) for 7 days before sampling, we cannot be certain if this effect is a stress reaction to the captivity or the normal level for this morph. However comparison with two sets of related salamanders that were captured and sampled immediately indicates the red-stripe salamanders were either not stressed from the captivity at all, or their white blood cell distributions had returned to normal after 7 days of captivity. Taken together, our results indicate that lead-phase forms of P. Cinereus have higher stress levels than the red-stripe forms, which may be a consequence of their higher exposure to, and/or attacks from, predators. They may also indicate that the lead-phase form is less-suited to captivity than the red-stripe form of this species.     

Magnetic resonance cholangiopancreatography and a problem in diagnosis of hepatopancreatoduodenal diseases

Based on the findings of 54 magnetic resonance studies, the authors used 19 of them authors to study the types of normalcy. A role of the new noninvasive technique magnetic resonance cholangiopancreatography (MRCPG) in the diagnosis of hepatopancreatoduodenal diseases is assessed. The potentialities of MRCPG in the detection of most common diseases and malformations of the biliary system are demonstrated. Comparative studies of MRCPG and endoscopic retrograde cholangiopancreatography (ERCPG) were conducted in 18 cases. The paper shows a methodological approach to MRCPG and analyzes the studies by describing the MR semiotics of major diseases. Emphasis is laid on how it is important to combine routine MRI and MRCPG in certain diagnostic situations. The authors consider that MRCPG is able to replace X-ray endoscopic studies and primarily ERCPG in diagnostic terms, by reserving their therapeutical functions for itself. MRCPG has great potentialities that, require further investigations and analysis.     

Mitochondrial DNA variation in two Russian populations from Novgorod oblast

Mitochondrial DNA (mtDNA) polymorphism was examined in two Russian populations of Novgorod oblast, from the city of Velikii Novgorod (n = 81), and the settlement of Volot (n = 79). This analysis showed that the mitochondrial gene pool of Russians examined was represented by the mtDNA types belonging to 20 haplogroups and subhaplogroups distributed predominantly among the European populations. Haplogroups typical of the indigenous populations of Asia were found in the population sample from Velikii Novgorod with the average frequency of 3.7% (haplogroups A, Z, and D5), and with the frequency of 6.3% (haplogroups Z, D, and M*) in the Volot population. It was demonstrated that the frequency of the mitochondrial lineages combination, D5, Z, U5b-16144, and U8, typical of the Finnish-speaking populations of Northeastern Europe, was somewhat higher in the urban population (7.4%) compared to rural one (3.8%). The problem of genetic differentiation of Russians from Eastern Europe inferred from mtDNA data, is discussed.