Low-temperature increases the yield of biologically active herring antifreeze protein in Pichia pastoris

Antifreeze proteins and antifreeze glycoproteins are structurally diverse molecules that share a common property in binding to ice crystals and inhibiting ice crystal growth. Type II fish antifreeze protein of Atlantic herring (Clupea harengus harengus) is unique in its requirement of Ca(2+) for antifreeze activity. In this study, we utilized the secretion vector pGAPZalpha A to express recombinant herring antifreeze protein (WT) and a fusion protein with a C-terminal six-histidine tag (WT-6H) in yeast Pichia pastoris wild-type strain X-33 or protease-deficient strain SMD1168H. Both recombinant proteins were secreted into the culture medium and properly folded and functioned as the native herring antifreeze protein. Furthermore, our studies demonstrated that expression at a lower temperature increased the yield of the recombinant protein dramatically, which might be due to the enhanced protein folding pathway, as well as increased cell viability at lower temperature. These data suggested that P. pastoris is a useful system for the production of soluble and biologically active herring antifreeze protein required for structural and functional studies.

Greater movement-related cortical potential during human eccentric versus concentric muscle contractions

Despite abundant evidence that different nervous system control strategies may exist for human concentric and eccentric muscle contractions, no data are available to indicate that the brain signal differs for eccentric versus concentric muscle actions. The purpose of this study was to evaluate electroencephalography (EEG)-derived movement-related cortical potential (MRCP) and to determine whether the level of MRCP-measured cortical activation differs between the two types of muscle activities. Eight healthy subjects performed 50 voluntary eccentric and 50 voluntary concentric elbow flexor contractions against a load equal to 10% body weight. Surface EEG signals from four scalp locations overlying sensorimotor-related cortical areas in the frontal and parietal lobes were measured along with kinetic and kinematic information from the muscle and joint. MRCP was derived from the EEG signals of the eccentric and concentric muscle contractions. Although the elbow flexor muscle activation (EMG) was lower during eccentric than concentric actions, the amplitude of two major MRCP components-one related to movement planning and execution and the other associated with feedback signals from the peripheral systems-was significantly greater for eccentric than for concentric actions. The MRCP onset time for the eccentric task occurred earlier than that for the concentric task. The greater cortical signal for eccentric muscle actions suggests that the brain probably plans and programs eccentric movements differently from concentric muscle tasks.

Chitinase genes responsive to cold encode antifreeze proteins in winter cereals

Antifreeze proteins similar to two different chitinases accumulate during cold acclimation in winter rye (Secale cereale). To determine whether these cold-responsive chitinases require post-translational modification to bind to ice, cDNAs coding for two different full-length chitinases were isolated from a cDNA library produced from cold-acclimated winter rye leaves. CHT9 is a 1,193-bp clone that encodes a 31.7-kD class I chitinase and CHT46 is a 998-bp clone that codes for a 24.8-kD class II chitinase. Chitinase-antifreeze proteins purified from the plant were similar in mass to the predicted mature products of CHT9 and CHT46, thus indicating that there was little chemical modification of the amino acid sequences in planta. To confirm these results, the mature sequences of CHT9 and CHT46 were expressed in Escherichia coli and the products of both cDNAs modified the growth of ice. Transcripts of both genes accumulated late in cold acclimation in winter rye. Southern analysis of winter rye genomic DNA indicated the presence of a small gene family homologous to CHT46. In hexaploid wheat, CHT46 homologs mapped to the homeologous group 1 chromosomes and were expressed in response to cold and drought. We conclude that two novel cold-responsive genes encoding chitinases with ice-binding activity may have arisen in winter rye and other cereals through gene duplication.

Overexpression and purification of human calcineurin alpha from Escherichia coli and assessment of catalytic functions of residues surrounding the binuclear metal center

Calcineurin is an important signal-transducing enzyme in many cell types including T lymphocytes and is a common target for the immunosuppressants cyclosporin A and FK506. The crystal structures of both calcineurin [Griffith et al. (1995) Cell 82, 507-522; Kissinger et al. (1995) Nature 378, 641-644] and a related enzyme, protein phosphatase-1 [Goldberg et al. (1995) Nature 376, 745-753], revealed that this class of serine/threonine phosphatases contain in their putative active sites a binuclear metal center formed by an Asn, two Asp, and three His residues. In addition, one His and two Arg residues lie in close vicinity of the binuclear metal centers. The importance of the binuclear metal center and its surrounding residues in catalysis by calcineurin has not been investigated experimentally. Herein, we report an efficient bacterial expression and purification system for human calcineurin alpha. Using this system, a systematic alanine-scan mutagenesis on the residues surrounding the putative active site was performed. It was found that an intact binuclear metal center is essential for the catalytic activity of the enzyme. In addition, His151, Arg122, and Arg254 also exhibited either a loss or a dramatic decrease in catalytic activity upon mutation into alanines. Interestingly, the Arg254Ala mutant retained a small but significant amount of catalytic activity toward the small substrate p-nitrophenyl phosphate, but is completely inactive toward a phosphopeptide substrate, suggesting that this arginine may be involved in the binding of phosphoprotein substrates as well as in catalysis. As all the residues in the putative active site are conserved between different eukaryotic serine/threonine phosphatases, these results should apply to all members of this family of protein phosphatases.

Organic nitrate chemistry and its implications for nitrogen budgets in an isoprene- and monoterpene-rich atmosphere: constraints from aircraft (SEAC4RS) and ground-based (SOAS) observations in the Southeast US

Formation of organic nitrates (RONO₂) during oxidation of biogenic volatile organic compounds (BVOCs: isoprene, monoterpenes) is a significant loss pathway for atmospheric nitrogen oxide radicals (NO_x), but the chemistry of RONO₂ formation and degradation remains uncertain. Here we implement a new BVOC oxidation mechanism (including updated isoprene chemistry, new monoterpene chemistry, and particle uptake of RONO₂) in the GEOS-Chem global chemical transport model with ∼25 × 25 km² resolution over North America. We evaluate the model using aircraft (SEAC⁴RS) and ground-based (SOAS) observations of NO_x, BVOCs, and RONO₂ from the Southeast US in summer 2013. The updated simulation successfully reproduces the concentrations of individual gas- and particle-phase RONO₂ species measured during the campaigns. Gas-phase isoprene nitrates account for 25-50% of observed RONO₂ in surface air, and we find that another 10% is contributed by gas-phase monoterpene nitrates. Observations in the free troposphere show an important contribution from long-lived nitrates derived from anthropogenic VOCs. During both campaigns, at least 10% of observed boundary layer RONO₂ were in the particle phase. We find that aerosol uptake followed by hydrolysis to HNO₃ accounts for 60% of simulated gas-phase RONO₂ loss in the boundary layer. Other losses are 20% by photolysis to recycle NO_x and 15% by dry deposition. RONO₂ production accounts for 20% of the net regional NO_x sink in the Southeast US in summer, limited by the spatial segregation between BVOC and NO_x emissions. This segregation implies that RONO₂ production will remain a minor sink for NO_x in the Southeast US in the future even as NO_x emissions continue to decline.

Distinct tissue and cellular distribution of two major isoforms of calcineurin

The protein phosphatase calcineurin is known to be an essential intracellular signal transducer involved in the TCR-mediated signal transduction pathway and is the common target of the immunosuppressive drugs cyclosporin A (CsA) and FK506. The catalytic subunit of calcineurin exists in multiple isoforms, but their functional differences are not known. It has been assumed that the alpha isoform of calcineurin is the relevant isoform mediating TCR signaling. Recently, calcineurin alpha was knocked out in mice, but no defect in the TCR-mediated IL-2 production was observed, suggesting that another isoform of calcineurin mediates the TCR signal transduction pathway. We have generated specific polyclonal antibodies against the alpha and the beta2 isoforms of calcineurin and examined their distribution in murine tissues and immune cells by immunohistochemical staining and Western blot analysis. We found that the beta2 isoform of calcineurin is predominant in T and B lymphocytes as well as in thymus compared to the alpha isoform, suggesting that the beta2 isoform may play a key role in TCR signaling. Furthermore, we observed that the two isoforms exhibit distinct expression patterns in both kidney and thymus, indicating that the two isoforms of calcineurin have distinct cellular functions. Together, these findings raise the possibility that the nephrotoxicity associated with CsA and FK506 can be reduced by designing novel inhibitors of calcineurin that target specific isoforms of the enzyme.

Activated beta-catenin induces myogenesis and inhibits adipogenesis in BM-derived mesenchymal stromal cells

BACKGROUND

Mesenchymal stromal cells (MSC) have been thought to be attractive candidates for the treatment of degenerative muscle diseases. However, little is known about the molecular mechanisms governing the myogenic differentiation in MSC. As the Wnt signaling pathway has been associated with myogenesis in embryogenesis and post-natal muscle regeneration, we hypothesized that the Wnt signaling pathway may be involved in governing the myogenic differentiation in MSC.

METHODS

Primary MSC were isolated from Sprague-Dawley rats and expanded in proliferation medium. The rMSC were transfected with a constitutively active hbeta-catenin (S37A) plasmid or control vector by Lipofectamine followed by G418 selection. The transfected rMSC were grown to 80% confluence and then cultured in myogenic or adipogenic differentiation medium. Cells were characterized by light microscopy, immunofluorescence and RT-PCR at different time points after myogenic or adipogenic introduction.

RESULTS

Ectopic expression of activated beta-catenin located primarily in the nucleus and activated transcription in rMSC. Overexpression of stabilized beta-catenin induced 27.1 +/- 3.91% rMSC forming long multinucleated cells expressing MyoD, myogenin, desmin and myosin heavy chain (MHC) via evoking the expression of skeletal muscle-specific transcription factors. In addition, overexpression of activated beta-catenin inhibited the adipogenic differentiation in rMSC through down-regulated expressions of C/EBPalpha and PPARgamma.

DISCUSSION

To our knowledge, this is the first evidence that activated beta-catenin can induce myogenic differentiation in rMSC. The ability of stabilized beta-catenin to induce myogenic differentiation in rMSC may allow for its therapeutic application.

Liver-specific and seasonal expression of transgenic Atlantic salmon harboring the winter flounder antifreeze protein gene

We have analyzed the inheritance and expression of a line of transgenic salmon harboring the antifreeze protein gene from the winter flounder. The genomic clone 2A-7 coding for a major liver-type antifreeze protein gene (wflAFP-6) was integrated into the salmon genome. From a transgenic founder (#1469), an F3 generation was produced. In this study, southern blot analysis showed that only one copy of the antifreeze protein transgene was integrated into a unique site in F3 transgenic fish. The integration site was cloned and characterized. Northern analysis indicated that the antifreeze protein mRNA was only expressed in the liver and showed seasonal variation. All of the F3 offspring contained similar levels of the antifreeze protein precursor protein in the sera and the sera of these offspring showed a characteristic hexagonal ice crystal pattern indicating the presence of antifreeze activity. In addition, the antifreeze protein precursor protein level was found to vary with the season, being highest in the month of November and lowest in May. This study had demonstrated a tissue-specific and stable expression of the antifreeze protein transgene in the F3 generation of the transgenic salmon 1469 line.

Structural and physiological characterization during wheat pericarp development

The cytological and physiological features of developing wheat pericarp were clearly characterized in this report. Our results may be helpful to articulate the functions of pericarp during the seed development. Although wheat pericarp has been well studied, knowledge of the sequence of events in the process of pericarp development is incomplete. In the present study, the structural development process of wheat (Triticum aestivum L.) pericarp was investigated in detail using resin microtomy and microscopy. Chlorophyll contents, and photosynthetic and respiratory rates, in pericarp were determined using spectrophotometer and an oxygen electrode, respectively. Mineral nutrient contents were also determined using scanning electron microscopy. The main results are as follows: (1) based on the structures and physiological characteristics observed, the developmental process of pericarp was divided into four stages, growth, formation, extinction and maturation stages, pericarp exhibited specific features at each stage. (2) Pericarp development differed in different parts, or varieties, of wheat. The dorsal pericarp had fewer starch grains and slower rates of apoptosis than the abdominal mesocarp. The cross cells in dorsal pericarp had an irregular outline. When compared with soft wheat cv. Yangmai 11, mesocarp cells in hard wheat cv. Xumai 30 had more starch grains, larger cell size and longer development duration. (3) The chlorophyll content, photosynthesis rate and respiratory rate in pericarp increased gradually, reaching a maximum about 16 days after anthesis, and later decreased continually. The photosynthetic rate in pericarp was lower than the respiration rate. (4) The contents of mineral elements in pericarp, such as calcium, zinc, iron and potassium were higher than those in the inner endosperm. The data indicate that wheat pericarp has many functions, e.g. protection, photosynthesis, mineral accumulation, synthesis and degradation of starch.

G(E(p))/G(M(p)) ratio by polarization transfer in e-->p --> ep-->

The ratio of the proton's elastic electromagnetic form factors, G(E(p))/G(M(p)), was obtained by measuring P(t) and P(l), the transverse and the longitudinal recoil proton polarization, respectively. For elastic e-->p-->ep-->, G(E(p))/G(M(p)) is proportional to P(t)/P(l). Simultaneous measurement of P(t) and P(l) in a polarimeter provides good control of the systematic uncertainty. The results for the ratio G(E(p))/G(M(p)) show a systematic decrease as Q2 increases from 0.5 to 3.5 GeV2, indicating for the first time a definite difference in the spatial distribution of charge and magnetization currents in the proton.

Dentin dysplasia type I-A dental disease with genetic heterogeneity

Hereditary dentin disorders include dentinogenesis imperfecta (DGI) and dentin dysplasia (DD), which are autosomal dominant diseases characterized by altered dentin structure such as abnormality in dentin mineralization and the absence of root dentin. Shields classified DGI into three subgroups and DD into two subtypes. Although they are all hereditary dentin diseases, they do not share the same causative genes. To date, the pathogenic genes of DGI type I, which is considered a clinical manifestation of syndrome osteogenesis imperfecta, include COL1A1 and COL1A2. Mutations of the DSPP gene, which encodes the dentin sialophosphoprotein, a major non-collagenous protein, are responsible for three isolated dentinal diseases: DGI-II, DGI-III, and DD-II. However, DD-I appears to be special in that researchers have found three pathogenicity genes-VPS4B, SSUH2, and SMOC2-in three affected families from different countries. It is believed that DD-I is a genetically heterogeneous disease and is distinguished from other types of dentin disorders. This review summarizes the DD-I literature in the context of clinical appearances, radiographic characteristics, and functions of its pathogenic genes and aims to serve clinicians in further understanding and diagnosing this disease.

Functional analysis of estrogen-responsive elements in chinook salmon (Oncorhynchus tschawytscha) gonadotropin II beta subunit gene

The salmon gonadotropin II gene regulates ovulation and spawning. Analysis of the 5' flanking sequence of the hormone-specific beta-subunit of salmon gonadotropin II (sGTHII beta) gene reveals the presence of several presumptive estrogen-responsive elements (ERE). The participation of ERE in the control of sGTHII beta gene transcription was examined by the transient expression of sGTHII beta gene promoter-chloramphenicol acetyltransferase chimeric DNA constructs in HeLa cells, with the cotransfection of a rainbow trout estrogen receptor expression vector. Three ERE have been identified: the proximal ERE [pERE, at -267 base pair (bp) from the transcription start site], the distal ERE (dERE, at -2698 bp, three GGTCA motifs each separated by exactly 31 bp), and the half-ERE (1/2ERE, at -157 bp as a GGTCA motif), respectively. The pERE (TGTCAATCTGACC) represents a novel but less effective variation of the consensus ERE (cERE). The dERE is a unique estrogen-induced enhancer. It requires the participation of the pERE to be functional and the enhancer activity of pERE and dERE is promoter specific. The contribution of 1/2ERE is minor and is not cell-type specific. The activation of the ERE in the sGTHII beta gene and the synergistic cooperation between the dERE and pERE by estradiol-17 beta is dose dependent. DNA sequences in the vicinity of the ERE decreases their hormone responsiveness and the synergism between dERE and pERE. These negative regions may contribute to the quiescent endocrine state of the sGTHII beta gene during the regressive phase of the reproductive cycle in teleost.

The relationship between multimorbidity and suicidal ideation: A meta-analysis

OBJECTIVE

Multimorbidity refers to the individual has two or more medical conditions, which include physical multimorbidity (two or more physical conditions), mental multimorbidity (two or more mental conditions) and physical and mental multimorbidity (one or more mental and one or more physical conditions). This study is to assess the relationship between multimorbidity and suicidal ideation (SI) by conducting a meta-analysis.

METHODS

Through using subject word and random word, Web of Science, Cochrane Library and PubMed were searched for related records up to March 2020. The Newcastle-Ottawa scale and the Agency for Healthcare Research and Quality were used to evaluate the quality of included studies. Subgroup and sensitivity analysis were performed. The publication bias was evaluated by the funnel plots, Begg's test and Egger's test.

RESULTS

A total of 19 studies were included for analysis. The pooled odd ratio (OR) for the association between multimorbidity and SI was 2.90 (95%CI 2.29-3.67, P < .001). Subgroup analysis based on nature of study, category of multimorbidity, country, whether adjusted the covariates, and quality ratings was performed. The result of sensitivity analysis indicated that no individual studies had a substantial impact on the pooled OR. There was no publication bias in the studies.

CONCLUSIONS

Multimorbidity is one important factor in increased risk of SI. It is critical to assessing SI among patients with multimorbidity in primary care and specialty medical practices, particularly among physical and mental multimorbidity patients who may have higher risk of SI.

A zebrafish ftz-F1 (Fushi tarazu factor 1) homologue requires multiple subdomains in the D and E regions for its transcriptional activity

A zebrafish Ftz-F1 homologue, zFF1A (zebrafish Ff1a or Nr5a2, a member of nuclear receptor superfamily) and its C-terminally truncated variant (zFF1B) were previously identified. Due to lack of the identity box (I-box) and activation function 2 (AF-2) domain, zFF1B lacks transactivation function and fails to synergize with estrogen receptor (ER) in regulating promoters. It was speculated that the I-box might be involved in the zFF1A/ER interaction. In the present study, the function of the I-box was examined. In the absence of the I-box or with an altered heptad 9, the AF-2 of zFF1A was not functional, either in the presence or absence of ER. The GST pull-down assay showed that zFF1A and its mutants exerted similar physical contacts with ER-LBD, suggesting that the "dimerization" domain (I-box) is essential for the transcriptional activity of zFF1A. Moreover, nuclear receptor coactivator selectively activated zFF1 with the I-box but exerted no effect on zFF1B, indicating that the I-box is able to interact with the coactivators. By deletion study and analysis of the identified domains in GAL4-DNA binding domain, other regions of zFF1A critical for its AF were also delineated. Consistent with the mutation analysis, AF-2 was active only in the presence of the I-box. We also identified a novel AF domain (AF-3) located in the hinge region (amino acids 155-267), although the activity of AF-3 was inhibited by its flanking region. We suggest that the D and E regions of zFF1A possess both positive and negative transactivation functions, and interdomain "cross-talk" may confer the full transcriptional activity of the protein.

Presence of distinct cis-acting elements on gonadotropin gene promoters in diverse species dictates the selective recruitment of different transcription factors by steroidogenic factor-1

The nuclear receptor steroidogenic factor-1 (SF-1) regulates the cell-specific expression of the pituitary gonadotropin subunit genes. Several potential DNA-binding sites for SF-1, estrogen receptor (ER) and the immediate-early transcription factor NGFI-A are found in LHbeta genes from many species. In this study, we have examined the action and interaction of these transcription factors on LHbeta gene promoters from two representative vertebrate species, i.e. rat and salmon. Cotransfection studies in COS-1 cells have shown that the action of SF-1 on salmon gonadotropin IIbeta (sGTHIIbeta) gene promoter was dramatically enhanced when combined with ER. The rat LHbeta promoter was activated by SF-I or ER individually, but these two factors, however, were unable to act in synergism on this promoter. In contrast, NGFI-A, specifically in cooperation with SF-1, transactivated the rat LHbeta gene expression but was ineffective on the sGTHIIbeta gene. Gel shift experiments showed that this lack of activation was due to the low affinity of the salmon NGFI-A-responsive element for its binding protein. In conclusion, our studies demonstrate that differential recruitment of distinct transcription factors by SF-1 might be a common mechanism to activate the cell-specific gonadotropin gene expression in different species.

Expression of APOB, ADFP and FATP1 and their correlation with fat deposition in Yunnan's top six famous chicken breeds

1. Adipose differentiation related protein (ADFP), fatty acid transport protein 1 (FATP1) and apolipoprotein B (APOB) are suspected to play an important role in determining intramuscular fat and in overall meat quality. 2. Yunnan's top six famous chicken breeds (the Daweishan Mini, Yanjin Black-bone, Chahua, Wuding, Wuliangshan Black-bone and Piao chicken) are known for the high quality of their meat, but little is known about their expression of these three genes. 3. The present study aimed to examine the ADFP, FATP1 and APOB genes in different tissues of these six breeds at different development stages. The subcutaneous fat from the back midline and front, abdominal fat, liver and muscle tissue was sampled at 28, 49, 70, 91 and 112 days. The expression of ADFP, FATP1 and APOB was measured by real-time PCR. 4. The results showed that the expression of the three genes differed depending on age, tissue types and breeds. However, the expression of the three genes correlated with fat traits. In conclusion, the expression of the ADFP, FATP1 and APOB genes is associated with the fat traits of Yunnan's top six chicken breeds. These results could help with molecular marker screening and marker-assisted breeding to improve the quality of poultry for meat production.

Etude sur les acides fulviques extraits d'eaux superficielles françaises - Extraction, caractérisation et réactivité avec le chlore

Après avoir présenté quelques données bibliographiques sur les substances humiques aquatiques, l'extraction de plusieurs substances humiques issues de onze eaux de surface françaises, est discutée en terme de rendements d'extraction. Quelques paramètres de caractérisation des acides fulviques sont présentés et en particulier, l'analyse élémentaire, l'absorption UV, les fonctions carboxyles et les potentiels de réactivité avec le chlore. Concernant la chloration, une attention particulière a été portée d'une part sur la nature produits organo-chlorés formés et d'autre part sur les corrélations qui existent entre la nature des acides fulviques et leur potentiel de réactivité avec le chlore.

Steroidogenic factor 1 and estradiol receptor act in synergism to regulate the expression of the salmon gonadotropin II beta subunit gene

The orphan nuclear receptor steroidogenic factor-1 (SF-1) regulates the expression of several genes involved in the reproductive function and development of the adrenal, the gonads, and the pituitary gonadotropes. It also confers the gonadotrope-specific expression of the glycoprotein hormone a subunit gene by the binding to a gonadotrope-specific element (GSE). In this study, we have shown that SF-1 transactivates the salmon gonadotropin II beta subunit (sGTHII beta) gene expression. SF-1 alone offered a slight but significant enhancement on sGTHII beta promoter activity (7.2 +/- 0.6 fold). However, it stimulated sGTHII beta gene expression dramatically (127 +/- 37 fold) when combined with the estrogen receptor (ER). This synergistic interaction was specific for sGTHII beta promoter as well as for both SF-1 and ER and was estradiol-dose dependent. 5'-Deletion studies of the sGTHII beta promoter identified two putative SF-1 binding sites (GSE) and one previously identified proximal estrogen-responsive element (pERE) at -274 bp involved in this activation. The two GSE sequences located at -354 bp (sGSE(3) and -162 bp (sGSE(2) upstream of the transcription site, although imperfect as compared with the consensus GSE, bound specifically to the in vitro-translated mouse SF-1 protein. 5'-Deletion studies, competition experiments, and site-directed mutagenesis showed that binding to pERE and GSE(2) were necessary for the SF-1/ER synergistic effect. These studies suggest that the synergistic interaction of SF-1 and ER, possibly through cooperative binding or protein-protein interaction, is essential in conferring a cell type-specific expression of the GTHII beta subunit gene.