RF2a, a bZIP transcriptional activator of the phloem-specific rice tungro bacilliform virus promoter, functions in vascular development

Rice tungro bacilliform virus (RTBV) replicates only in phloem cells in infected rice plants and its promoter drives strong phloem-specific reporter gene expression in transgenic rice plants. We isolated a cDNA encoding a basic leucine zipper (bZIP) protein, RF2a, which binds to the Box II cis element that is important for expression from the promoter. RF2a, which stimulates Box II-dependent transcription in a homologous in vitro transcription system, accumulates in nuclei of phloem and certain other cell types in shoots, but is found at only very low levels in roots. Transgenic antisense plants in which RF2a accumulation was suppressed had normal roots but stunted, twisted leaves with small, disorganized vascular bundles, an enlarged sclerenchyma and large air spaces. We propose that the RTBV promoter exploits a host transcription factor that is critical for leaf tissue differentiation and vascular development for its expression.

Experimental cryptorchidism induces testicular germ cell apoptosis by p53-dependent and -independent pathways in mice

Cryptorchidism is associated with male infertility: germ cell loss occurs by apoptosis in response to elevated temperature. Since the tumor suppressor p53 is highly expressed in the testis and is known to induce apoptosis, an investigation was undertaken to establish whether heat stress causes p53-mediated germ cell apoptosis. Using a mouse model of experimental unilateral cryptorchidism, it was observed that testicular weight reduction, germ cell loss, and DNA fragmentation all began in the cryptorchid testes on Day 6-7 in wild-type mice. In contrast, these changes were delayed by 3 days in p53-/- mice. These results suggest that abdominal heat stress induces germ cell loss through two apoptotic pathways: a p53-dependent pathway responsible for the initial phase of germ cell apoptosis, and a p53-independent pathway that accounts for subsequent apoptosis.

Mapping and characterization of a novel cochlear gene in human and in mouse: a positional candidate gene for a deafness disorder, DFNA9

Previously we identified a partial human cDNA for a novel cochlear transcript, hCoch-5B2 (HGMW-approved symbol D14S564E), using subtractive hybridization techniques. Herein we report isolation and characterization of both human and mouse (D12H14S564E) cDNAs for Coch-5B2. Full-length Coch5B2 deduced amino acid sequences reveal a very high degree of conservation in the coding region (89% nucleotide and 94% amino acid identity and a potential signal peptide and two regions of extensive homology to the collagen-binding type A domains of von Willebrand factor, also present in other secreted proteins, including extracellular matrix components. High levels of hCoch-5B2 expression are seen only in human fetal inner ear structures, cochlea, and vestibule, among a large panel of human fetal and adult tissues. Coch-5B2 expression in the mouse is more widespread than in the human, with message detected in mouse adult spleen, cerebrum, cerebellum/medulla, and thymus. In both species very low level expression is detected in total eye. More specifically, mouse retina shows a higher level of mCoch-5B2 message than sclera and choroid. We have mapped hCoch-5B2 to human 14q11.2-q13 by somatic cell hybrid analysis and FISH and, more precisely, using radiation hybrids to a region of markers linked to DFNA9, a nonsyndromic autosomal dominant sensorineural hearing loss with vestibular defects. Furthermore, we detect hCoch-5B2 on three overlapping YACs, two of which also contain one of the markers linked to DFNA9. mCoch-5B2 was genetically mapped in the mouse to chromosome 12, in a region of homologous synteny with human 14q11.2-q13, which contains the asp1 (audiogenic seizure prone) locus in the mouse.

Stability of family interaction from ages 6 to 18

Research has demonstrated the stability of juvenile offending during childhood and adolescence but generally has not focused on the continuity of family interactions associated with juvenile offending. The present report focused on the stability of several family interaction events and attributes (i.e., physical punishment, communication, supervision, positive parenting, and parent-child relationship) for a large sample of male adolescents and their primary caretakers, drawn from a multiyear longitudinal study that represented middle childhood through late adolescence (ages 6-18). We also assessed the impact of ethnicity, family composition, teenage motherhood, and youth delinquency on these interactions. Test-retest correlations and growth-curve analyses were used to assess relative and absolute stability of the interactions, respectively. As predicted, relative stability of family interaction was high. There was an absolute change in scores of physical punishment (decreased) compared to poor supervision and low positive parenting (both increased), whereas poor communication and bad relationship with the caretaker did not measurably change with age. Single-parent families and families with teenage mothers experienced significantly worse interactions over time than did families consisting of two biological parents present in the household. These findings are discussed in relation to the development of juvenile offending.

Characterization of sterol demethylation inhibitor-resistant isolates of Fusarium asiaticum and F. graminearum collected from wheat in China

Fusarium asiaticum and F. graminearum are the primary causal agents of Fusarium head blight (FHB) of wheat in China. In this study, sensitivities of 159 F. asiaticum and F. graminearum isolates to a benzimidazole fungicide carbendazim (MBC) and to sterol demethylation inhibitors (DMIs) tebuconazole and prochloraz were determined. Among the 159 isolates, 9 were resistant to MBC and designated as MBC-R isolates. Three showed resistance to tebuconazole and prochloraz and designated as DMI-R isolates. There was no cross-resistance between MBC and DMI. Genetic analysis by microsatellite-primed polymerase chain reaction (PCR) showed that MBC-R or DMI-R isolates had different genotypes, which indicated that they originated from different wild-type parents. Analysis of two 14alpha-demethylase (cyp51) homologous genes (cyp51A and cyp51B) showed that the F. asiaticum isolates could be distinguished from F. graminearum isolates based on the sequence of cyp51A. Analysis of deduced amino acid sequence of cyp51A and cyp51B suggested that no mutations were associated with DMI resistance. Real-time PCR analysis showed that the DMI resistance was not related to the expression of cyp51A and cyp51B in F. asiaticum and F. graminearum, but expressions of both genes were induced greatly by the tebuconazole. Results of this study indicated that cyp51A would be an informative marker for analysis of population structure of F. asiaticum and F. graminearum, and the existence of homologous cyp51 genes in F. asiaticum and F. graminearum could provide new insights into DMI resistance in phytopathogenic fungi.

Imaging of pelvic insufficiency fractures

Insufficiency fractures of the pelvis are being increasingly recognized as a major cause of low back pain in elderly women with osteoporosis. Fractures in the sacrum are difficult to diagnose, as plain radiographic findings are either unhelpful or misleading. Bone scintigraphy is very sensitive for the detection of fractures in the sacrum, with demonstration of the H-shaped (or butterfly) sacral pattern or the combination of concomitant sacral and parasymphyseal uptake being considered as characteristic of insufficiency fractures. Computed tomography (CT) is helpful for confirming the presence of fractures in cases with atypical scintigraphic patterns, particularly in those with a known primary malignant neoplasm. CT is especially useful in the further evaluation of parasymphyseal and pubic rami lesions. The majority of patients respond well to periods of enforced bed rest and administration of analgesics. Recognition of the spectrum of imaging findings for this entity should lead to its correct identification and the institution of appropriate treatment.

p53-mediated germ cell quality control in spermatogenesis

Spontaneous germ cell death is a common cellular process in the mammalian testis, although the function of this process during spermatogenesis is unclear. An investigation was undertaken to determine whether p53 serves as a mechanism in germ cell quality control by causing spontaneous germ cell death. Using an annexin V assay, lower levels of spontaneous apoptosis were found in the testes of p53-/- mice compared to p53+/+ mice. Propidium iodine staining revealed that the greatest reduction in apoptosis and the largest increase in cell numbers occurred in the tetraploid germ cell population of p53-/- mice. Microscopic examination of sperm morphology showed an increased percentage of abnormal forms in p53-/- mice. Furthermore, p53-/- mice sired fewer offspring than p53+/+ mice did when both groups were mated with p53+/+ females. These results suggest that p53 mediates spontaneous testicular germ cell apoptosis and failure to remove defective germ cells by this mechanism results in increased percentages of abnormal sperm and reduced fertility. p53-mediated apoptosis may be an effector of cellular proofreading that acts to maintain the cellular integrity of germ cells during spermatogenesis.

Abnormalities in whole-brain functional connectivity observed in treatment-naive post-traumatic stress disorder patients following an earthquake

BACKGROUND

Convergent studies have highlighted the dysfunction of the amygdala, prefrontal cortex and hippocampus in post-traumatic stress disorder (PTSD). However, only a few studies have investigated the functional connectivity between brain regions in PTSD patients during the resting state, which may improve our understanding of the neuropathophysiology of PTSD. The aim of this study was to investigate patterns of whole-brain functional connectivity in treatment-naive PTSD patients without co-morbid conditions who experienced the 8.0-magnitude earthquake in the Sichuan province of China.

METHOD

A total of 72 PTSD patients and 86 trauma-exposed non-PTSD controls participated in the resting-state functional magnetic resonance imaging study. All these subjects were recruited from the disaster zone of the 2008 Sichuan earthquake. Functional connectivities between 90 paired brain regions in PTSD patients were compared with those in trauma-exposed non-PTSD controls. Furthermore, Pearson correlation analysis was performed between significantly abnormal connectivities in PTSD patients and their clinician-administered PTSD scale (CAPS) scores.

RESULTS

Compared with non-PTSD controls, PTSD patients showed weaker positive connectivities between the middle prefrontal cortex (mPFC) and the amygdala, hippocampus, parahippocampal gyrus and rectus, as well as between the inferior orbitofrontal cortex and the hippocampus. In addition, PTSD patients showed stronger negative connectivity between the posterior cingulate cortex (PCC) and the insula. The CAPS scores in PTSD patients correlated negatively with the connectivity between the amygdala and the mPFC.

CONCLUSIONS

PTSD patients showed abnormalities in whole-brain functional connectivity, primarily affecting the connectivities between the mPFC and limbic system, and connectivity between the PCC and insula.

SOX9 is a regulator of ADAMTSs-induced cartilage degeneration at the early stage of human osteoarthritis

OBJECTIVE

To identify whether cartilage master regulator SRY-related protein 9 (SOX9) mediates A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) dysregulation during osteoarthritis (OA) cartilage degeneration.

METHOD

Twenty-two randomly selected OA patients were evaluated using Outerbridge Classification via arthroscopy. Haematoxylin-eosin (HE), Safranin O and Masson staining were performed for the histopathological assessment. The expression of ADAMTSs, collagen 2A1 (COL2A1), aggrecan (ACAN), cartilage oligomeric matrix protein (COMP) and SOX9 were examined using real-time quantitative Polymerase Chain Reaction (PCR) (RT-qPCR) and western blotting analysis. Immunohistochemistry (IHC) analysis was performed to investigate the production of ADAMTSs in cartilage tissues. The association between SOX9 production and ADAMTSs, COL2A1, ACAN, and COMP expression was established by full-depth cartilage biopsies.

RESULTS

ADAMTSs expression levels were repressed at stage 1, while a significant increase was observed at the progressive stage of OA. SOX9 was upregulated at stage 1 and suppressed at a later stage of cartilage development, particularly in cartilage with severe damage. In addition, SOX9 repressed the expression of ADAMTSs and promoted COL2A1, ACAN and COMP expression in human chondrocytes. SOX9 was recruited to the promoters of ADAMTS-4 and ADAMTS-7. SOX9 expression was negatively correlated with ADAMTSs production and was positively associated with COL2A1, ACAN and COMP expression. Inhibition of ADAMTSs markedly increased the production of COL2A1, ACAN and COMP in chondrocytes isolated from the early stage of OA.

CONCLUSIONS

These findings indicated that SOX9 upregulation might mediate ADAMTSs suppression at the early stage of human OA. In addition, SOX9 could be used as a potential therapeutic agent for human OA at an early stage.

Regulatory circuit of PKM2/NF-κB/miR-148a/152-modulated tumor angiogenesis and cancer progression

Upregulation of the embryonic M2 isoform of pyruvate kinase (PKM2) emerges as a critical player in the cancer development and metabolism, yet the underlying mechanism of PKM2 overexpression remains to be elucidated. Here we demonstrate that IGF-1/IGF-IR regulates PKM2 expression by enhancing HIF-1α-p65 complex binding to PKM2 promoter. PKM2 expression is regulated by miR-148a/152 suppression. PKM2 directly interacts with NF-κB p65 subunit to promote EGR1 expression for regulating miR-148a/152 feedback circuit in normal cells, but not in cancer cells because of the DNA hypermethylation of miR-148a and miR-152 gene promoters. The silencing of miR-148a/152 contributes to the overexpression of PKM2, NF-κB or/and IGF-IR in some cancer cells. We show that disruption of PKM2/NF-κB/miR-148a/152 feedback loop can regulate cancer cell growth and angiogenesis, and is also associated with triple-negative breast cancer (TNBC) phenotype, which may have clinical implication for providing novel biomarker(s) of TNBC and potential therapeutic target(s) in the future.

Identification and expression of mouse netrin-4

Netrins are secreted proteins that serve as potent axon guidance molecules in vertebrates and invertebrates. We report the identification of a novel mammalian member of this family. Netrin-4 is similar in predicted size and secondary structure to the other three netrins; all contain, in order, an amino-terminal signal sequence, a laminin-type globular domain of the 'VI' type, three laminin-type epidermal growth factor (EGF) repeats, and a carboxyl-terminal 'netrin module'. In terms of primary sequence, however, netrin-4 is a distant relative of netrins-1-3, and its globular domain is more closely related to those of laminins than to those of other netrins. Netrin-4 is broadly expressed in both neural and non-neural tissues of embryonic and adult mice. In embryonic spinal cord, it is selectively expressed by cells at the lateral margins of the floor plate. In postnatal brain, it is selectively expressed in subsets of neurons, including cerebellar granule and hippocampal pyramidal cells.

Diet, aberrant crypt foci and colorectal cancer

We have used the aberrant crypt focus (ACF) assay to test and develop hypotheses linking diet and colon cancer. The hypotheses were suggested by epidemiological studies that identified possible dietary factors associated with colorectal cancer risk. The ACF assay was used to quantitate the effect of the dietary factors on the initiation and growth of these putative precursors of colon cancers in experimental animals. Using this approach we have developed 3 new hypotheses for the role of diet in colorectal cancer. These are (1) a risk associated with 5-hydroxymethyl-2-furaldehyde in caramelized sugar, (2) a risk associated with some factor in thermolyzed casein, and (3) a risk associated with single nutrient boluses of sucrose and fructose. The importance of these hypotheses has still to be tested in long term carcinogenesis experiments, in analytic epidemiology studies and then, perhaps, in intervention trials.

The role of macrophages in optic nerve regeneration

Following injury to the nervous system, the activation of macrophages, microglia, and T-cells profoundly affects the ability of neurons to survive and to regenerate damaged axons. The primary visual pathway provides a well-defined model system for investigating the interactions between the immune system and the nervous system after neural injury. Following damage to the optic nerve in mice and rats, retinal ganglion cells, the projection neurons of the eye, normally fail to regenerate their axons and soon begin to die. Induction of an inflammatory response in the vitreous strongly enhances the survival of retinal ganglion cells and enables these cells to regenerate lengthy axons beyond the injury site. T cells modulate this response, whereas microglia are thought to contribute to the loss of retinal ganglion cells in this model and in certain ocular diseases. This review discusses the complex and sometimes paradoxical actions of blood-borne macrophages, resident microglia, and T-cells in determining the outcome of injury in the primary visual pathway.

Lack of functional retinoblastoma protein mediates increased resistance to antimetabolites in human sarcoma cell lines

Growth inhibition assays indicated that the IC50 values for methotrexate (MTX) and 5-fluorodeoxyuridine (FdUrd) in HS-18, a liposarcoma cell line lacking retinoblastoma protein (pRB), and SaOS-2, an osteosarcoma cell line with a truncated and nonfunctional pRB, were 10- to 12-fold and 4- to 11-fold higher, respectively, than for the HT-1080 (fibrosarcoma) cell line, which has wild-type pRB. These Rb-/- cell lines exhibited a 2- to 4-fold increase in both dihydrofolate reductase (DHFR) and thymidylate synthase (TS) enzyme activities as well as a 3- to 4-fold increase in mRNA levels for these enzymes compared to the HT-1080 (Rb+/+) cells. This increase in expression was not due to amplification of the DHFR and TS genes. Growth inhibition by MTX and FdUrd was increased and DHFR and TS activities and expression were correspondingly decreased in Rb transfectants of SaOS-2 cells. In contrast, there was no significant difference in growth inhibition among these cell lines for the nonantimetabolites VP-16, cisplatin, and doxorubicin. A gel mobility-shift assay showed that parental SaOS-2 cells had increased levels of free E2F compared to the Rb-reconstituted SaOS-2 cells. These results indicate that pRB defective cells may have decreased sensitivity to growth inhibition by target enzymes encoded by genes whose transcription is enhanced by E2F proteins and suggest mechanisms of interaction between cytotoxic agents and genes involved in cell cycle progression.

Tumor suppressor p53 is required to modulate BRCA1 expression

Individuals carrying mutations in BRCA1 or p53 genes are predisposed to a variety of cancers, and both tumor suppressor genes have been implicated in DNA damage response pathways. We have analyzed a possible functional link between p53 and BRCA1 genes. Here we show that BRCA1 expression levels are down-regulated in response to p53 induction in cells that undergo either growth arrest, senescence, or apoptosis. Physiological stimuli, such as exposure to DNA-damaging agents, also result in negative regulation of BRCA1 levels in a p53-dependent manner prior to causing cell cycle arrest. Nuclear run-on experiments and luciferase reporter assays demonstrate that the changes in BRCA1 expression are mainly due to transcriptional repression induced by p53. In conclusion, the data show that BRCA1 expression levels are controlled by the presence and activity of wild-type p53 and suggest the existence of an intracellular p53/BRCA1 pathway in the response of cells to stress conditions.

Conformational changes at the active site of creatine kinase at low concentrations of guanidinium chloride

It has been previously reported that, during denaturation of creatine kinase by guanidinium chloride (GdmCl) or urea [Tsou (1986), Trends Biochem. Sci. 11, 427-429], inactivation occurs before noticeable conformational change can be detected, and it is suggested that the conformation at the active site is more easily perturbed and hence more flexible than the molecule as a whole. In this study, the thiol and amino groups at or near the active site of creatine kinase are labelled with o-phthalaldehyde to form a fluorescent probe. Both the emission intensity and anisotropy decrease during denaturation indicating exposure of this probe and increased mobility of the active site. The above conformational changes take place together with enzyme inactivation at lower GdmCl concentrations than required to bring about intrinsic fluorescence changes of the enzyme. At the same GdmCl concentration, the rate of exposure of the probe is comparable with that of inactivation and is several orders of magnitude faster than that for the unfolding of the molecule as a whole.

Review: Chinese herbs as alternatives to antibiotics in feed for swine and poultry production: Potential and challenges in application

Gong, J., Yin, F., Hou, Y. and Yin, Y. 2014. Chinese herbs as alternatives to antibiotics in feed for swine and poultry production: Potential and challenges in application. Can. J. Anim. Sci. 94: 223–241. Traditional Chinese medicine (TCM) has a long history of clinical practice, and its own theoretical framework focused on functions at the whole-body level. However, due to cultural differences, TCM has not been fully recognized in Western countries. With the recent development of the theory of whole-body systems biology and “-omics”, there is a new opportunity to study TCM and to close the gap between TCM and Western medicine, because of the similarity in the theoretical foundations between TCM and whole-body systems biology. The uniqueness of TCM theory and practice is the approach to maintain and restore the body balance as a whole with no or little unfavourable side effects. Recent studies have also shown that Chinese herbs used as feed additives can modulate nutritional metabolism, immune responses, and intestinal health of food-producing animals, demonstrating good potential as substitutes for dietary antibiotics. Nonetheless, some issues need to be addressed before Chinese herbs can reach their full application. This article has critically reviewed recent progresses in scientific research of Chinese herbs as feed additives and their potential to replace dietary antibiotics. Possible challenges in future application for swine and poultry production are also discussed.

Identification of a carbohydrate recognition domain in filamentous hemagglutinin from Bordetella pertussis

The adherence of Bordetella pertussis to ciliated cells and macrophages is critical to colonization and infection of the respiratory tract. Adherence to both types of cells involves the recognition of eukaryotic carbohydrates by the bacterial adhesin filamentous hemagglutinin (Fha). The carbohydrate recognition domain (CRD) of Fha is considered an important antigen for subcomponent vaccines to maximize the generation of antiadherence antibodies capable of protecting against colonization. For identification of the CRD of Fha, a bank of eight monoclonal antibodies (MAbs) that mapped to four contiguous regions were tested for their ability to block Fha binding to lactosylceramide or to block bacterial binding to ciliated cells. Only MAb 12.5A9, which maps to amino acid residues 1141 to 1279, blocked both Fha binding to lactosylceramide and bacterial binding to ciliated cells. An 18-kDa polypeptide corresponding to this region was expressed in Escherichia coli. Cell lysates containing this protein bound to lactosylceramide in a manner identical to that of native Fha. Mutant strains of B. pertussis that contained an in-frame deletion of the coding sequence for this region produced a truncated Fha that showed negligible cross-reactivity with MAb 12.5A9. In an adherence assay, these mutant strains failed to bind efficiently to either ciliated cells or macrophages. The numbers of adherent bacteria for these strains were reduced to the number obtained with a nonadherent strain. We conclude that the region defined by residues 1141 to 1279 of Fha constitutes a CRD critical for bacterial adherence and represents a potential candidate for a subcomponent vaccine.

Associative memory realized by a reconfigurable memristive Hopfield neural network

Although synaptic behaviours of memristors have been widely demonstrated, implementation of an even simple artificial neural network is still a great challenge. In this work, we demonstrate the associative memory on the basis of a memristive Hopfield network. Different patterns can be stored into the memristive Hopfield network by tuning the resistance of the memristors, and the pre-stored patterns can be successfully retrieved directly or through some associative intermediate states, being analogous to the associative memory behaviour. Both single-associative memory and multi-associative memories can be realized with the memristive Hopfield network.

2.9 A crystal structure of ligand-free tryptophanyl-tRNA synthetase: domain movements fragment the adenine nucleotide binding site

The crystal structure of ligand-free tryptophanyl-tRNA synthetase (TrpRS) was solved at 2.9 A using a combination of molecular replacement and maximum-entropy map/phase improvement. The dimeric structure (R = 23.7, Rfree = 26.2) is asymmetric, unlike that of the TrpRS tryptophanyl-5'AMP complex (TAM; Doublié S, Bricogne G, Gilmore CJ, Carter CW Jr, 1995, Structure 3:17-31). In agreement with small-angle solution X-ray scattering experiments, unliganded TrpRS has a conformation in which both monomers open, leaving only the tryptophan-binding regions of their active sites intact. The amino terminal alphaA-helix, TIGN, and KMSKS signature sequences, and the distal helical domain rotate as a single rigid body away from the dinucleotide-binding fold domain, opening the AMP binding site, seen in the TAM complex, into two halves. Comparison of side-chain packing in ligand-free TrpRS and the TAM complex, using identification of nonpolar nuclei (Ilyin VA, 1994, Protein Eng 7:1189-1195), shows that significant repacking occurs between three relatively stable core regions, one of which acts as a bearing between the other two. These domain rearrangements provide a new structural paradigm that is consistent in detail with the "induced-fit" mechanism proposed for TyrRS by Fersht et al. (Fersht AR, Knill-Jones JW, Beduelle H, Winter G, 1988, Biochemistry 27:1581-1587). Coupling of ATP binding determinants associated with the two catalytic signature sequences to the helical domain containing the presumptive anticodon-binding site provides a mechanism to coordinate active-site chemistry with relocation of the major tRNA binding determinants.