Altered nuclear distribution of recombination protein RAD51 in maize mutants suggests the involvement of RAD51 in meiotic homology recognition

The recombination protein RAD51 is a component of the meiotic recombination pathway and has been proposed to play a role in the homology search, a process by which homologous chromosomes find each other before they pair in the prophase of meiosis. To study the relationship between recombination and chromosome pairing, we examined the distribution of RAD51 foci on meiotic chromosomes in maize mutants with defects in chromosome pairing. The patterns of RAD51 distribution showed dramatic variation among the meiotic mutants. The mutants generally exhibited significant decreases in the number of RAD51 foci at zygotene, corresponding to the degree of their pairing defects. These results provide evidence for a key role of RAD51 structures in the homology search.     

Interaction between yeast eukaryotic initiation factor eIF4E and mRNA 5' cap analogues differs from that for murine eIF4E

Measurements of interaction of 7-methyl-GTP eIF4E from S. cerevisiae were performed by means of two methods: Isothermal Titration Calorimetry (ITC) and fluorescence titration. The equilibrium association constants (Kas) derived from the two methods show significantly different affinity of yeast eIF4E for the mRNA 5' cap than those of the murine and human proteins. The observed differences in the Kas values and the enthalpy changes of the association (deltaH(o)) suggest some dissimilarity in the mode of binding and stabilization of cap in the complexes with eIF4E from various sources.     

Antiendotoxin activity of protegrin analog IB-367 alone or in combination with piperacillin in different animal models of septic shock

The therapeutic efficacy of protegrin peptide IB-367 was investigated in three rat models of septic shock: (i) rats injected intraperitoneally with 1mg Escherichia coli 0111:B4 lipopolysaccharide, (ii) rats given an intraperitoneal injection of 2 X 10(10) CFU of E. coli ATCC 25922, and (iii) rats in which intra-abdominal sepsis was induced via cecal ligation and puncture. All animals were randomized to receive parenterally isotonic sodium chloride solution, 1mg/kg of IB-367, 60mg/kg piperacillin and 1mg/kg of IB-367 plus 60mg/kg piperacillin. The peptide demonstrated lower level of antimicrobial activity than piperacillin, nevertheless it exhibited the dual properties of antimicrobial and antiendotoxin agent. Finally IB-367 and piperacillin association showed to be the most effective therapeutic approach.     

The circling behavior of the deafblind LEW-<Emphasis Type="Italic">ci2</Emphasis> rat is linked to a segment of RNO10 containing <Emphasis Type="Italic">Myo15</Emphasis> and <Emphasis Type="Italic">Kcnj12</Emphasis>

The LEW/Ztm-ci2 rat is an autosomal recessive mutant that displays circling behavior, deafness, progressive retinopathy, locomotor hyperactivity, ataxia, and opisthotonus. We performed a genome-wide scan of a (LEW/Ztm-ci2 × BN/Ztm) F₁ × LEW/Ztm-ci2 backcross population with anonymous microsatellite markers to analyze the genetics of this mutant rat. This linkage analysis demonstrated a very strong association of RNO10 SSLP markers to the phenotype with a core region in the central part of the chromosome. The knowledge of genes mapping to this part of the rat genome and their linkage to SSLP markers is still poor. We developed SSLP markers closely linked to genes, which might be responsible for the mutant phenotype by using the growing amount of rat-specific DNA sequences available at World Wide Web databases. Application of this method facilitated the search for candidate genes for the phenotype of the LEW-ci2 rat. We were able to map Myo15 and its neighboring genes, Znf179 and Aldh3a1, to the region of interest and Myo1c to a more distal location on RNO10. Further rat BAC clones were used to create a physical map of the region of interest. This map revealed the position of further genes. Among those is Kcnj12. Owing to their localization on RNO10 and their involvement in a similar pathology in human and mouse, Myo15 and Kcnj12 can be regarded as candidate genes for the deafblind phenotype of the LEW-ci2 rat.     

Serological characterization of anti-endotoxin serum directed against the conjugate of oligosaccharide core of Escherichia coli type R4 with tetanus toxoid

The covalent conjugate of oligosaccharide core of Escherichia coli type R4 with tetanus toxoid was prepared using reaction of reductive amination. The neoglycoconjugate was a good immunogen in rabbits yielding a high level of anti-lipopolysaccharide (LPS) antibodies of the IgG class. It was found that antiserum was able to react with the smooth LPS molecules of identical (R4) or related (R1) core type. The reactions were shown in the enzyme-linked immunosorbent assay and the immunoblotting test. Flow cytometry showed that anti-core antibodies reacted with LPS present on intact, live, smooth bacteria labelling more than 90% of cells. The anti-OS R4-TT serum used for in vitro studies showed high endotoxin neutralization activity. The serum inhibited endotoxin-induced tumor necrosis factor alpha and nitric oxide synthesis by the J-774A.1 cell line and attenuated pulmonary retention of YAC-1 cells.     

Changes in serum copper level during detoxification of acutely poisoned drug addicts

Although it is known that drug addicts are a high-risk group for disruption of many homeostatic processes, little is know about changes in serum trace elements concentrations after taking the psychoactive substances. The aim of the study was to check the influence of the taking homemade heroin on serum level of copper. Blood samples were taken from 30 opiate addicts, and copper concentrations were measured by the means of atomic absorption spectrophotometry. The result of the study show that in the examined group, copper serum concentrations (1.35 mg/L) upon admission to the clinic were higher than in the control group (1.11 mg/L) but decreased during hospitalization (1.18 mg/L). There was no correlation between duration of stay at the hospital and changes in serum copper concentration.     

Irregular patterns of transgene silencing in allohexaploid oat

An irregular pattern of transgene silencing was revealed in expression and inheritance studies conducted over multiple generations following transgene introduction by microprojectile bombardment of allohexaploid cultivated oat (Avena sativa L.). Expression of two transgenes, bar and uidA, delivered on the same plasmid was investigated in 23 transgenic oat lines. Twenty-one transgenic lines, each derived from an independently selected transformed tissue culture, showed expression of both bar and uidA while two lines expressed only bar. The relationship of the transgenic phenotypes to the presence of the transgenes in the study was determined using (1) phenotypic scoring combined with Southern blot analyses of progeny, (2) coexpression of the two transgenic phenotypes since the two transgenes always cosegregated, and (3) reactivation of a transgenic phenotype in self-pollinated progenies of transgenic plants that did not exhibit a transgenic phenotype. Transgene silencing was observed in 19 of the 23 transgenic lines and resulted in distorted segregation of transgenic phenotypes in 10 lines. Silencing and inheritance distortions were irregular and unpredictable. They were often reversible in a subsequent generation of self-pollinated progeny and abnormally segregating progenies were as likely to trace back to parents that exhibited normal segregation in a previous generation as to parents showing segregation distortions. Possible causes of the irregular patterns of transgene silencing are discussed.     

A study on giant panda recognition based on images of a large proportion of captive pandas

1. As a highly endangered species, the giant panda (panda) has attracted significant attention in the past decades. Considerable efforts have been put on panda conservation and reproduction, offering the promising outcome of maintaining the population size of pandas. To evaluate the effectiveness of conservation and management strategies, recognizing individual pandas is critical. However, it remains a challenging task because the existing methods, such as traditional tracking method, discrimination method based on footprint identification, and molecular biology method, are invasive, inaccurate, expensive, or challenging to perform. The advances of imaging technologies have led to the wide applications of digital images and videos in panda conservation and management, which makes it possible for individual panda recognition in a noninvasive manner by using image‐based panda face recognition method.
2. In recent years, deep learning has achieved great success in the field of computer vision and pattern recognition. For panda face recognition, a fully automatic deep learning algorithm which consists of a sequence of deep neural networks (DNNs) used for panda face detection, segmentation, alignment, and identity prediction is developed in this study. To develop and evaluate the algorithm, the largest panda image dataset containing 6,441 images from 218 different pandas, which is 39.78% of captive pandas in the world, is established.
3. The algorithm achieved 96.27% accuracy in panda recognition and 100% accuracy in detection.
4. This study shows that panda faces can be used for panda recognition. It enables the use of the cameras installed in their habitat for monitoring their population and behavior. This noninvasive approach is much more cost‐effective than the approaches used in the previous panda surveys.

     

Characterization of pNiXa,a serpin of Xenopus laevis oocytes and embryos,and its histidine-rich,Ni(II)-binding domain

A Ni(II)-binding serpin, pNiXA, is abundant in Xenopus oocytes and embryos. Kinetic assays show that purified pNiXa strongly inhibits bovine α-chymotrypsin (K₁ = 3 mM), weakly inhibits porcine elastase (K₁ = 0.5 μM), and does not inhibit bovine trypsin. The reversible, slow-binding inhibition of α-chymotrypsin by pNiXa is unaffected by Ni(II). Ovochymase in egg exudates is inhibited by pNiXa, but to a limited extent, even at high pNiXa concentrations. An octadecapeptide that models the His-rich domain (-HRHRHEQQGHHDSAKHGH-) of pNiXa forms six-coordinate, octahedral Ni(II)-complexes when the N-terminus is acetylated, and a square-planar Ni(II)-complex when the N-terminus is unblocked. Spectroscopy reveals two distinct types of octahedral Ni(II)-coordination to the N-acetylated octadecapeptide, involving, respectively, 3–4 and 5–6 imidazole nitrogens; the octadecapeptide undergoes partial, reversible precipitation in pH-and Ni(II)-dependent fashion, suggesting an insoluble, Ni(II)-coupled (Hx)_n-dimer. Such (Hx)_n-peptide interaction is confirmed by an enzyme-linked biotin-avidin assay with N-biotin-KHRHRHE-amide and N-acetyl-KHRHRHE-resin beads, which become coupled after adding Ni(II) or Zn(II). H₂O₂ oxidation of 2′-deoxyguanosine to mutagenic 8-hydroxy-2′deoxyguanosine is enhanced by the octahedral Ni(II)-octadecapeptide complex, although the effect is more intense with the square-planar Ni(II) octadecapeptide complex. Immunoperoxidase staining of whole mounts wish pNiXa antibody shows that pNiXa is distributed throughout gastrula-stage embryos and is localized during organogenesis in the brain, eye, spinal cord, myotomes, craniofacial tissues, and other sites of Ni(II) induced anomalies. Patterns of pNiXa staining are similar in controls and Ni(II)-exposed embryos. Binding of Ni(II) to pNiXa may cause embryotoxicity by enhancing oxidative reactions that produce tissue injury and genotoxicity. Although the natural target proteinases for pNiXa inhibition have not been established, pNiXa may be an important regulator of proteolysis during embryonic development. © 1996 Wiley-Liss, Inc.     

Structure of human insulin monomer in water/acetonitrile solution

Here we present evidence that in water/acetonitrile solvent detailed structural and dynamic information can be obtained for important proteins that are naturally present as oligomers under native conditions. An NMR-derived human insulin monomer structure in H₂O/CD₃CN, 65/35 vol%, pH 3.6 is presented and compared with the available X-ray structure of a monomer that forms part of a hexamer (Acta Crystallogr. 2003 Sec. D59, 474) and with NMR structures in water and organic cosolvent. Detailed analysis using PFGSE NMR, temperature-dependent NMR, dilution experiments and CSI proves that the structure is monomeric in the concentration and temperature ranges 0.1–3 mM and 10–30°C, respectively. The presence of long-range interstrand NOEs, as found in the crystal structure of the monomer, provides the evidence for conservation of the tertiary structure. Starting from structures calculated by the program CYANA, two different molecular dynamics simulated annealing refinement protocols were applied, either using the program AMBER in vacuum (AMBER_VC), or including a generalized Born solvent model (AMBER_GB). Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Wojciech Bocian contributed equally to this work.