Evidence for a synergistic effect of post-translational modifications and genomic composition of eEF-1α on the adaptation of Phytophthora infestans

Genetic variation plays a fundamental role in pathogen's adaptation to environmental stresses. Pathogens with low genetic variation tend to survive and proliferate more poorly due to their lack of genotypic/phenotypic polymorphisms in responding to fluctuating environments. Evolutionary theory hypothesizes that the adaptive disadvantage of genes with low genomic variation can be compensated for structural diversity of proteins through post-translation modification (PTM) but this theory is rarely tested experimentally and its implication to sustainable disease management is hardly discussed. In this study, we analyzed nucleotide characteristics of eukaryotic translation elongation factor-1α (eEF-lα) gene from 165 Phytophthora infestans isolates and the physical and chemical properties of its derived proteins. We found a low sequence variation of eEF-lα protein, possibly attributable to purifying selection and a lack of intra-genic recombination rather than reduced mutation. In the only two isoforms detected by the study, the major one accounted for >95% of the pathogen collection and displayed a significantly higher fitness than the minor one. High lysine representation enhances the opportunity of the eEF-1α protein to be methylated and the absence of disulfide bonds is consistent with the structural prediction showing that many disordered regions are existed in the protein. Methylation, structural disordering, and possibly other PTMs ensure the ability of the protein to modify its functions during biological, cellular and biochemical processes, and compensate for its adaptive disadvantage caused by sequence conservation. Our results indicate that PTMs may function synergistically with nucleotide codes to regulate the adaptive landscape of eEF-1α, possibly as well as other housekeeping genes, in P. infestans. Compensatory evolution between pre- and post-translational phase in eEF-1α could enable pathogens quickly adapting to disease management strategies while efficiently maintaining critical roles of the protein playing in biological, cellular, and biochemical activities. Implications of these results to sustainable plant disease management are discussed.

Human-Mediated Gene Flow Contributes to Metapopulation Genetic Structure of the Pathogenic Fungus Alternaria alternata from Potato

Metapopulation structure generated by recurrent extinctions and recolonizations plays an important role in the evolution of species but is rarely considered in agricultural systems. In this study, generation and mechanism of metapopulation structure were investigated by microsatellite assaying 725 isolates of Alternaria alternata sampled from potato hosts at 16 locations across China. We found a single major cluster, no isolate-geography associations and no bottlenecks in the A. alternata isolates, suggesting a metapopulation genetic structure of the pathogen. We also found weak isolation-by-distance, lower among than within cropping region population differentiation, concordant moving directions of potato products and net gene flow and the highest gene diversity in the region with the most potato imports. These results indicate that in addition to natural dispersal, human-mediated gene flow also contributes to the generation and dynamics of the metapopulation genetic structure of A. alternata in China. Metapopulation structure increases the adaptive capacity of the plant pathogen as a result of enhanced genetic variation and reduced population fragmentation. Consequently, rigid quarantine regulations may be required to reduce population connectivity and the evolutionary potential of A. alternata and other pathogens with a similar population dynamics for a sustainable plant disease management.

Viruliferous rate of small brown planthopper is a good indicator of rice stripe disease epidemics

Rice stripe virus (RSV), its vector insect (small brown planthopper, SBPH) and climatic conditions in Jiangsu, China were monitored between 2002 and 2012 to determine key biotic and abiotic factors driving epidemics of the disease. Average disease severity, disease incidence and viruliferous rate of SBPH peaked in 2004 and then gradually decreased. Disease severity of RSV was positively correlated with viruliferous rate of the vector but not with the population density of the insect, suggesting that the proportion of vectors infected by the virus rather than the absolute number of vectors plays an important role in RSV epidemics and could be used for disease forecasting. The finding of a positive correlation of disease severity and viruliferous rate among years suggests that local infection is likely the main source of primary inoculum of RSV. Of the two main climatic factors, temperature plays a more important role than rainfall in RSV epidemics.

Effect of steam-flaked corn and soybeans on muscle and intramuscular fatty acid composition in Holstein calves

This study aimed to evaluate the effects of steam-flaked corn grains and soybeans on muscle fatty acid composition. Thirty Holstein bull calves (21 ± 3 d) were divided into 3 groups according to birth date and BW and were randomly assigned to receive fresh milk and a commercial pelleted starter diet containing extruded corn and soybean (ECS), steam-flaked corn and soybean (SFCS), or ground corn and raw soybean (GCS). The calves were fed the designated diet from 3 to 13 wk of age, after which they were slaughtered. The supraspinatus (CTM), longissimus lumborum (RLM), and spinalis dorsi (ERM) were analyzed to determine the chemical and intramuscular fatty acid composition. The fatty acid composition of muscle and its deposition differed among calves fed different starter feeds. Medium-chain fatty acid levels of the RLM and CTM were greater in GCS-fed calves than in ECS- and SFCS-fed calves ( < 0.05). Extruded processing increased the content of linoleic, linolenic, and arachidonic acids of the RLM ( < 0.05). The palmitoleic and -vaccenic acid content of the ERM were greater in GCS-fed calves than in ECS- or SFCS-fed calves ( < 0.05). No significant differences were observed among the 3 diets with respect to the stearic, oleic, linoleic, -9 -11 CLA, or arachidonic acid content of the ERM ( > 0.05). The levels of -3 and -6 fatty acids were similar among the 3 groups; a lower -6:-3 PUFA ratio was observed in GCS-fed calves ( < 0.05). The cereal processing method of the calf starter feed had no significant effect on the chemical composition of the CTM, RLM, or ERM. Therefore, different methods of processing corn and soybean in calf starter feeds had no effect on the chemical composition of the RLM, CTM, or ERM but had a significant effect on the intramuscular fatty acid composition.

Effect of Jianpi Bushen prescription on the expression of SHP-1 and apoptosis-related genes in chemically damaged model mice

We investigated the effect of Jianpi Bushen prescription (JBP) on the expression of the SHP-1 and apoptosis-related genes in chemically damaged model mice and a compound e-jiao slurry (EJS) group (positive control). Kunming mice received an abdominal injection of 100 mg/kg cyclophosphamide once a day for 3 consecutive days to induce chemical damage. The mice underwent lavage at a suspension of 0.1 g/kg low-dose JBP (100%), high-dose JBP (200%), and 0.2 mL/10 g EJS twice a day for 9 days. mRNA and protein expression of SHP-1 in bone marrow mononuclear cells was detected using real-time polymerase chain reaction and Western blot; mRNA expression of B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X (Bax) protein was detected by in situ hybridization. Expression of SHP-1 and Bax mRNA was significantly upregulated in the model group compared to the control group (P < 0.05). Expression in the low-dose JBP, high-dose JBP, and EJS groups was significantly downregulated compared with the model group (P < 0.05). The low-dose JBP group exhibited much lower SHP-1 and Bax mRNA expression levels. Compared with controls, Bcl-2 mRNA expression was significantly reduced in the model group (P < 0.05). Expression in the low-dose JBP, high-dose JBP, and EJS groups significantly increased compared with the model group (P < 0.05). The low-dose JBP group showed much higher Bcl-2 mRNA expression. Therefore, JBP regulates the expression of the SHP- 1, Bax, and Bcl-2 genes in chemically damaged mice.

Effect of the Jianpi Bushen Prescription on the expression of SHP-1, Wnt3a, and AP-1 proteins in chemically damaged mice

This study investigated the effect of the Jianpi Bushen Prescription (JBP) on the expression of 3 major proteins in chemically damaged model mice. The 3 proteins were the Wnt3a, the SHP-1, and the transcription factors (NF-E2, c-jun, and c-fos) of the AP-1 protein family. Kunming mice were randomly divided into chemically damaged group (N=48), which received an abdominal injection of (100 mg/kg) cyclophosphamide once a day for 3 consecutive days, and control group (N=12), which received the same amount of saline. Then, the chemically damaged mice were randomly divided into chemically damaged model group (N=12), which received 0.2 mL/10 g of saline twice a day for 9 days, positive control group (N=12), which received 0.2 mL/10 g of the e-jiao slurry (EJS) compound twice a day for 9 days, low dose JBP group (N=12), which received 0.1 g/kg suspension JBP (100% concentration) twice a day for 9 days and high dose JBP group (N=12), which received 0.1 g/kg suspension JBP (200% concentration) twice a day for 9 days. The bilateral femur and tibia bone marrow were collected from the mice in all groups. The protein expression of the specified proteins and transcription factors in the bone marrow mononuclear cells were detected by Western blot analysis. The results showed that the protein expression of Wnt3a was significantly downregulated in the chemically damaged model group compared to the control group (P<0.05). The low dose JBP, high dose JBP, and e-jiao slurry treatments significantly upregulated the protein expression of Wnt3a compared to the chemically damaged model group (P<0.05), with the low dose JBP producing the best results. Compared to the control group, the protein expressions of SHP-1, c-fos, c-jun, and NF-E2 were significantly higher in the chemically damaged model group (all P<0.05). The protein expressions of SHP-1, c-fos, c-jun, and NF-E2 were significantly lower in the chemically damaged model+the low dose JBP, chemically damaged model+high dose JBP, or chemically damaged model+EJS group compared to chemically damaged model (all P<0.05), with the low dose JBP producing the best results. These results indicate that JBP regulates the expressions of SHP-1, Wnt3a, and AP-1 proteins in chemically damaged mice.

Effect of the Jianpi Bushen Prescription on expressions of the Wnt3a and Cyclin D1 genes in radiation-damaged mice

The effects of the traditional Chinese drug Jianpi Bushen Prescription (JBP) were investigated on expressions of Wnt3a and Cyclin D1 genes in radiation-damaged mice. The radiation damage model was induced in Kumming mice by single total body irradiation treatment for 9 days. Mice were divided into the radiation group, low-dose (100%) JBP group, high-dose (200%) JBP group, or batyl alcohol group (positive control), which were administered twice a day for 9 days. mRNA and protein expressions of Wnt3a were detected in bone marrow mononuclear cells by real-time polymerase chain reaction and Western blot, whereas Cyclin D1 mRNA was detected by in situ hybridization. Wnt3a expressions were significantly downregulated in the radiation damage model group compared with all other groups (P < 0.05). The positive cell rate of Cyclin D1 mRNA expression and the number of granulocyte macrophage colonies were significantly decreased in the radiation damage model group relative to all other groups (P < 0.05). Furthermore, mRNA and protein expressions of Wnt3a, the positive cell rate of Cyclin D1 mRNA expression in bone marrow cells, and the number of granulocyte macrophage colonies were all significantly higher in the low-dose JBP group than in the high-dose JBP group (P < 0.05). In summary, JBP plays a protective role on radiation-induced bone marrow through the activation of the Wnt3a signaling pathway, and promotes the transcription and expression of Cyclin D1.

Dynamics of human replication protein A subunit distribution and partitioning in the cell cycle

Human replication protein A (RPA) is a three-sub-unit protein complex involved in DNA replication, repair, and recombination. To gain insight into the dynamics of subunit assembly, we examined the subcellular distribution of RPA subunits (p70, p34, and p11) during the cell cycle. All three subunits colocalized in G1 and S phases, showing a diffuse nuclear distribution in G1 but a dot-like nuclear pattern in S phase. During S phase, the subunits showed a pattern reminiscent of the replication granules/factories described by others as sites of replication machinery. In meta-phase, p70 preferentially associated with the spindle poles, p34 was found on chromosomes, and p11 remained in the cytoplasm. In telophase, p70 and p34 appeared in the forming daughter nuclei; p11 remained in the cytoplasm until G1. Among the three subunits only p34 was associated with the nuclear matrix and this association persisted throughout the cell cycle. We conclude that (i) RPA complex assembly is differentially regulated, (ii) the replication machinery may be anchored to the nuclear matrix, and (iii) RPA subunits partition during mitosis and sort into daughter nuclei by different routes.

Localization of heterogeneous nuclear ribonucleoprotein in the interphase nuclear matrix core filaments and on perichromosomal filaments at mitosis

Although heterogeneous nuclear RNA (hnRNA) has been localized to the core filament substructure of the nuclear matrix, its precise location in the filament network has been unknown. The fA12 monoclonal antibody can localize, at high resolution, hn ribonucleoproteins (hnRNPs) and, presumably, hnRNA. Gold bead immunolabeling of resinless electron microscopy sections showed the fA12 antigens were in the fibrogranular material enmeshed in the filament network and not in the filaments themselves. At mitosis, hnRNP antigens became dispersed into a halo surrounding the chromosomes and spindle poles. Immunogold staining showed fA12 stained fibrogranular material associated with perichromosomal and pericentriolar filaments distinct from the mitotic spindle fibers. fA12 also labeled the midbody remaining after cytokinesis.

Core filaments of the nuclear matrix

The nuclear matrix is concealed by a much larger mass of chromatin, which can be removed selectively by digesting nuclei with DNase I followed by elution of chromatin with 0.25 M ammonium sulfate. This mild procedure removes chromatin almost completely and preserves nuclear matrix morphology. The complete nuclear matrix consists of a nuclear lamina with an interior matrix composed of thick, polymorphic fibers and large masses that resemble remnant nucleoli. Further extraction of the nuclear matrices of HeLa or MCF-7 cells with 2 M sodium chloride uncovered a network of core filaments. A few dark masses remained enmeshed in the filament network and may be remnants of the nuclear matrix thick fibers and nucleoli. The highly branched core filaments had diameters of 9 and 13 nm measured relative to the intermediate filaments. They may serve as the core structure around which the matrix is constructed. The core filaments retained 70% of nuclear RNA. This RNA consisted both of ribosomal RNA precursors and of very high molecular weight hnRNA with a modal size of 20 kb. Treatment with RNase A removed the core filaments. When 2 M sodium chloride was used directly to remove chromatin after DNase I digestion without a preceding 0.25 M ammonium sulfate extraction, the core filaments were not revealed. Instead, the nuclear interior was filled with amorphous masses that may cover the filaments. This reflected a requirement for a stepwise increase in ionic strength because gradual addition of sodium chloride to a final concentration of 2 M without an 0.25 M ammonium sulfate extraction uncovered core filaments.

Immunolocalization in three dimensions: immunogold staining of cytoskeletal and nuclear matrix proteins in resinless electron microscopy sections

We describe two methods for staining resinless thin sections with antibodies and gold-conjugated second antibodies. Immunolocalization of specific proteins is a powerful tool for cell structure studies but current techniques do not develop its full potential. Immunofluorescence provides only low-resolution localization, whereas conventional thin-section electron microscopy images and immunostains only the section surface. Resinless sections of extracted cell structures offer a simple and effective means of immuno-electron microscopy. Without embedding plastic or soluble proteins, the cell cytostructure produces high-contrast, three-dimensional images. Resinless sections of detergent-extracted cells are prepared by embedding in diethylene glycol distearate, sectioning, and removing diethylene glycol distearate before microscopy. In the first method of immunostaining, extracted cells were fixed and stained with antibodies before embedment, sectioning, removal of the embedding resin, and critical point drying. In the postembedment method, the sample was embedded and sectioned, the diethylene glycol distearate was removed, and the sample was rehydrated before antibody staining. With these techniques, specific proteins were localized with high resolution throughout the entire section. Stereoscopic micrographs of resinless sections revealed the precise localization of specific cytoskeleton and nuclear matrix proteins in three dimensions with unprecedented clarity.

Repair of severe tissue loss and deformity of maxillofacial area

Our experience in the management of 125 patients with massive facial defects since 1975 is detailed. The defects were closed in one of four principal ways (or a combination thereof): (1) free flap, (2) musculocutaneous flap, (3) forehead flap, and (4) dorsal tube flap. The surgical details and indications for each of these are outlined and examples given.