Do Unique Proteins Exist in Taste Buds?

Proteins in papillae on the bovine tongue were analyzed by semi-micro, polyacrylamide gel electrophoresis. All the proteins in the papillae with taste buds were observed to be common to proteins in the surrounding epithelium without taste buds. The protein band which was reported to form a weak complex with compounds called sweet by man was also found in all parts of the tongue epithelium. The receptor molecules for chemical stimuli may be distributed in all the cells of the tongue epithelium or the content of receptor molecules in taste bud papillae may be extremely low.     

Circulating Th17 cytokine levels are altered in Hashimoto’s thyroiditis

The disrupted autoimmune response in Hashimoto’s thyroiditis (HT) has long been considered to be dominantly T helper type 1 (Th1) mediated. Recent advances in the field of immunology have introduced a new class of effector T cells, named ‘Th17’, which plays important roles in autoimmune disorders once thought to be merely Th1 mediated. We aimed to examine the levels of major Th17 cytokines in patients with HT in this study. We studied serum interleukin 17 (IL-17) and interleukin 23 (IL-23) levels in 46 newly diagnosed, untreated patients with HT (40 women and 6 men, aged 40.0 ± 11.8 years) divided into euthyroid (n = 22) and hypothyroid (n = 24) groups and compared them with age and sex matched 26 healthy euthyroid controls without HT (21 women and 5 men; aged 36.0 ± 12.9 years). Serum IL-17 and IL-23 levels were significantly different among euthyroid and hypothyroid HT patients and controls, with highest levels obtained in the euthyroid HT group (p = 0.041 for IL-17 and p < 0.001 for IL-23). TSH was negatively and FT4 was positively correlated with IL-17 (p = 0.016 for TSH and p = 0.004 for FT4) and IL-23 (p < 0.001 for TSH and p = 0.003 for FT4) levels. There were no correlations between thyroid volumes calculated on thyroid ultrasonography and IL-17 (p = 0.630) or IL-23 (p = 0.321) levels. In conclusion, the levels of IL-17, one of the major effector cytokines of the Th17 system, and IL-23, which had been implicated in the generation, survival and expansion of Th17 cells, are altered in HT. How thyroid hormone status and the course of disease affect Th17 system in chronic autoimmune thyroiditis needs to be determined with further studies.     

Is There a Phylogenetic Signal in Prokaryote Proteins?

Using the sequence information from nine completely sequenced bacterial genomes, we extract 32 protein families that are thought to contain orthologous proteins from each genome. The alignments of these 32 families are used to construct a phylogeny with the neighbor-joining algorithm. This tree has several topological features that are different from the conventional phylogeny, yet it is highly reliable according to its bootstrap values. Upon closer study of the individual families used, it is clear that the strong phylogenetic signal comes from three families, at least two of which are good candidates for horizontal transfer. The tree from the remaining 29 families consists almost entirely of noise at the level of bacterial phylum divisions, indicating that, even with large amounts of data, it may not be possible to reconstruct the prokaryote phylogeny using standard sequence-based methods. Received: 22 November 1998 / Accepted: 17 February 1999     

ω-Helices in Proteins

A modification of the α-helix, termed the ω-helix, has four residues in one turn of a helix. We searched the ω-helix in proteins by the HELFIT program which determines the helical parameters—pitch, residues per turn, radius, and handedness—and p = rmsd/(N ? 1)^1/2 estimating helical regularity, where “rmsd” is the root mean square deviation from the best fit helix and “N” is helix length. A total of 1,496 regular α-helices 6–9 residues long with p ≤ 0.10 Å were identified from 866 protein chains. The statistical analysis provides a strong evidence that the frequency distribution of helices versus n indicates the bimodality of typical α-helix and ω-helix. Sixty-two right handed ω-helices identified (7.2% of proteins) show non-planarity of the peptide groups. There is amino acid preference of Asp and Cys. These observations and analyses insist that the ω-helices occur really in proteins.     

How are the Non-classically Secreted Bacterial Proteins Released into the Extracellular Milieu?

Most bacterial proteins that are destined to leave the cytoplasm are exported across the cell membrane to their sites of function. These proteins are generally exported via the classical secretion pathway, in which the signal peptide plays a central role. However, some bacterial proteins have been found in the extracellular milieu without any apparent signal peptide. As none of the classical secretion systems is involved in their secretion, this occurrence is termed non-classical protein secretion. The mechanism or mechanisms responsible for non-classical secretion are contentious. This review compiles evidence from the debate over whether the release of the non-classically secreted proteins is the result of cell lysis and discusses how these proteins are exported to the exterior of the cell.     

How objective are genera in euascomycetes?

Intra- and intergeneric distances derived from maximum-likelihood phylogenetic trees inferred from 254 nuclear ITS rDNA sequences were examined for seven families of euascomycetes, representing five classes. The intra- and intergeneric distances were well separated in most cases, but the distances varied between families. The analysis of the distance distributions provides a powerful tool for identifying certain taxa with highly deviating distances and thus cases of excessive lumping or splitting. Some cases of lumping and splitting found in different families are briefly discussed. The results of the analysis show that the generic concepts differ between the families. The consequences for nomenclature are discussed and a method abandoning binomial nomenclature while keeping the style of species names is recommended to ensure nomenclatural stability.     

Cytoskeletal proteins F-actin and β-dystrobrevin are altered by the cryopreservation process in bull sperm

The cryopreservation process has an important impact on sperm structure and physiology. The negative effects have been mainly observed on the plasma membrane, which is directly stabilized by the cytoskeleton. Since cytoskeleton proteins are osmosensitive and thermosensitive, the aim of this study was to evaluate the damage caused to the bull sperm cytoskeleton by cryopreservation (freezing-thawing). Fresh and frozen-thawed bull semen samples were exposed to a treatment with the neutral detergent Brij 36-T. Electron microscopy evidenced important damages at the sperm perinuclear theca after the protein extraction protocol; the perinuclear theca was partially solubilized, the perinuclear theca substructure disappeared in the cryopreserved samples. Furthermore, the sperm head's shape was significantly altered on the cryopreserved samples. Fluorescence analysis showed a decrease of the intensity of actin and dystrobrevin on the frozen-thawed samples. Western blot assays revealed a stronger signal for actin and β-dystrobrevin in the frozen-thawed sperm samples than in the fresh ones. Our results suggest that the cryopreservation process highly alters the sperm cytoskeleton stability, causing its proteins to become more fragile and therefore more susceptible to be extracted.     

Predator–prey interactions and metabolic rates are altered in stable and unstable groups in a social fish

Understanding the determinants and consequences of predation effort, success and prey responses is important since these factors affect the fitness of predators and prey. When predators are also invasive species, the impacts on prey can be particularly far-reaching with ultimate ecosystem-level consequences. However, predators are typically viewed as behaviourally fixed within this interaction and it is unclear how variation in predator social dynamics affects predator–prey interactions. Using the invasive eastern mosquitofish Gambusia holbrooki and a native glass shrimp Paratya australiensis in Australia, we investigated how varying levels of social conflict within predator groups influences predator–prey interactions. By experimentally manipulating group stability of G. holbrooki, we show that rates of social conflict were lower in groups with large size differences, but that routine metabolic rates were higher in groups with large size differences. Predation effort and success did not vary depending on group stability, but in stable groups predation effort by aggressive dominants was greater than subordinates. The anti-predator responses of prey to the stability of predator groups were mixed. While more prey utilized shelters when exposed to stable compared to unstable groups of predators, a greater proportion were sedentary when predator groups were unstable. Overall, this study demonstrates predator group stability is modulated by differences in body size and can influence prey responses. Further, it reveals a hidden metabolic cost of living in stable groups despite reduced overt social conflict. For invasive species management, it is therefore important to consider the behavioural and physiological plasticity of the invasive predators, whose complex social interactions and metabolic demands can modulate patterns of predator–prey interactions.     

Does Intrinsic Disorder in Proteins Favor Their Interaction with Lipids?

Intrinsically disordered proteins (IDPs) are implicated in a range of human diseases, some of which are associated with the ability to bind to lipids. Although the presence of solvent‐exposed hydrophobic regions in IDPs should favor their interactions with low‐molecular‐weight hydrophobic/amphiphilic compounds, this hypothesis has not been systematically explored as of yet. In this study, the analysis of the DisProt database with regard to the presence of lipid‐binding IDPs (LBIDPs) reveals that they comprise, at least, 15% of DisProt entries. LBIDPs are classified into four groups by ligand type, functional categories, domain structure, and conformational state. 57% of LBIDPs are classified as ordered according to the CH‐CDF analysis, and 70% of LBIDPs possess lengths of disordered regions below 50%. To investigate the lipid‐binding properties of IDPs for which lipid binding is not reported, three proteins from different conformational groups are rationally selected. They all are shown to bind linoleic (LA) and oleic (OA) acids with capacities ranging from 9 to 34 LA/OA molecules per protein molecule. The association with LA/OA causes the formation of high‐molecular‐weight lipid–protein complexes. These findings suggest that lipid binding is common among IDPs, which can favor their involvement in lipid metabolism.     

Uterine extracellular matrix components are altered during defective decidualization in interleukin-11 receptor α deficient mice

Background

Implantation of the embryo and successful pregnancy are dependent on the differentiation of endometrial stromal cells into decidual cells. Female interleukin-11 receptor α (IL-11Rα) deficient mice are infertile due to disrupted decidualization, suggesting a critical role for IL-11 and its target genes in implantation. The molecular targets of IL-11 in the uterus are unknown, but it is likely that IL-11 signaling modifies the expression of other genes important in decidualization. This study aimed to identify genes regulated by IL-11 during decidualization in mouse uterus, and to examine their expression and localization as an indication of functional significance during early pregnancy.

Methods

Decidualization was artificially induced in pseudopregnant wild type (IL11Ra^+/+) and IL-11Rα deficient (IL11Ra^-/-) littermates by oil injection into the uterine lumen, and gene expression analyzed by NIA 15K cDNA microarray analysis at subsequent time points. Quantitative real-time RT-PCR was used as an alternative mRNA quantitation method and the expression and cellular localization of the protein products was examined by immunohistochemistry.

Results

Among 15,247 DNA probes, 13 showed increased and 4 decreased expression in IL11Ra^-/- uterus at 48 h of decidualization. These included 4 genes encoding extracellular matrix proteins; collagen III α1, secreted acidic cysteine-rich glycoprotein (SPARC), biglycan and nidogen-1 (entactin). Immunohistochemistry confirmed increased collagen III and biglycan protein expression in IL11Ra^-/- uterus at this time. In both IL11Ra^-/- and wild type uterus, collagen III and biglycan were primarily localized to the outer connective tissue and smooth muscle cells of the myometrium, with diffuse staining in the cytoplasm of decidualized stromal cells.

Conclusion

These data suggest that IL-11 regulates changes in the uterine extracellular matrix that are necessary for decidualization.

     

Do induced sperm-head abnormalities in mice specifically identify mammalian mutagens rather than carcinogens?

The results of testing 54 compounds including 19 carcinogen/non-carcinogen pairs from a wide range of chemical classes are reported. Many carcinogens did not induce increases in abnormal sperm heads. In contrast compounds known to induce transmissible genetic damage in whole animals invariably induced dose-dependent large increases in the incidence of abnormal sperm heads. The test may be useful in assisting discrimination between compounds that only cause mutations in isolated cell systems from those which constitute a real genetic hazard for whole mammals.     

Can changes in sarcolemmal membranes account for the altered inotropic responsiveness in hypertrophied heart?

Hypertrophy is an adaptive mechanism of the heart subjected to pressure overload. Ultrastructural, electrophysiological and mechanical changes occur during this adaptation. A decrease in the inotropic responsiveness of the hypertrophied heart has often been observed as compared to the normal heart. Four sarcolemmal mechanisms that could account for this modification have been described. The mechanism of action of each system (calcium channel, alpha-and beta-adrenergic systems, (Na+,K+)-ATPase) of the hypertrophied heart has been compared to that of the normal heart. In spite of the paucity of results available relating to the calcium channel, the lengthening of the action potential in every case of compensatory hypertrophy could be explained by an altered functioning of the calcium channel. alpha- and beta-adrenergic systems in the hypertrophied heart could be modified at the receptor level itself, or at another level in the cascade of events under their control. For example, two different models of hypertrophy showed a decreased inotropic responsiveness correlated to a defect in the GS regulatory protein. The modification of the ouabain-receptor (Na+,K+)-ATPase mediates a decrease and a prolongation of the inotropic response. According to the modifications of each system, a direct relationship does not seem to exist between the stimulated membrane system and the inotropic responsiveness of the hypertrophied heart.     

Were Ancestral Proteins Less Specific?

Some have hypothesized that ancestral proteins were, on average, less specific than their descendants. If true, this would provide a universal axis along which to organize protein evolution and suggests that reconstructed ancestral proteins may be uniquely powerful tools for protein engineering. Ancestral sequence reconstruction studies are one line of evidence used to support this hypothesis. Previously, we performed such a study, investigating the evolution of peptide-binding specificity for the paralogs S100A5 and S100A6. The modern proteins appeared more specific than their last common ancestor (ancA5/A6), as each paralog bound a subset of the peptides bound by ancA5/A6. In this study, we revisit this transition, using quantitative phage display to measure the interactions of 30,533 random peptides with human S100A5, S100A6, and ancA5/A6. This unbiased screen reveals a different picture. While S100A5 and S100A6 do indeed bind to a subset of the peptides recognized by ancA5/A6, they also acquired new peptide partners outside of the set recognized by ancA5/A6. Our previous work showed that ancA5/A6 had lower specificity than its descendants when measured against biological targets; our new work shows that ancA5/A6 has similar specificity to the modern proteins when measured against a random set of peptide targets. This demonstrates that altered biological specificity does not necessarily indicate altered intrinsic specificity, and sounds a cautionary note for using ancestral reconstruction studies with biological targets as a means to infer global evolutionary trends in specificity.     

Does the autoimmune serum 5051 specifically recognise microtubule organising centres in plant cells?

The autoimmune serum 5051 recognises pericentriolar microtubule nucleating sites in animal cells. Because this whole serum immunostains higher plant cells it has previously been suggested that it is detecting microtubule organising centres in plants. From a study comparing immunostaining and immunoblotting activity of 5051 and normal human serum controls, in various plant and animal cells, we argue that there is no clear evidence to support this suggestion. A normal human serum, that did not recognise animal cell pericentriolar material, had a staining pattern in Allium cells indistinguishable from 5051. The spindle poles in Funaria or Chlamydomonas were not recognised by 5051 and several normal human sera mimicked the 5051 staining patterns observed. There was no similarity in the sizes of proteins detected by 5051 in animals and plants, and no proteins were detected only by 5051 and other sera giving the same staining.     

Age- and Sex-Associated Effects on Acute-Phase Proteins in G?ttingen Minipigs

Göttingen minipigs are a useful model for diseases having an inflammatory component, and the associated use of acute-phase proteins (APP) as biomarkers of inflammation warrants establishment of their reference ranges. The objective of this study was to establish reference values for selected APP in Göttingen minipigs and to investigate the effects of age, sex, and various stimuli on these ranges. Serum concentrations of C-reactive protein (CRP), serum amyloid A (SAA), haptoglobin, pig major acute-phase protein (PMAP), albumin, and porcine α-1 acid glycoprotein (PAGP) were evaluated in 4 age groups (6, 16, 24 and 40–48 wk) of male and female Göttingen minipigs. In addition, minipigs were tested under 2 housing conditions, after acute LPS challenge, and after diet-induced obesity with and without mild diabetes. Changing the pigs to a new environment induced significant increases in CRP, PMAP, haptoglobin and PAGP and a decrease in albumin. An acute LPS stimulus increased CRP, PMAP, haptoglobin, and SAA; PAGP was unchanged and albumin decreased. Obese pigs with and without diabetes showed increases in CRP and PAGP, albumin decreased, and haptoglobin and SAA were unchanged. PMAP was increased only in obese pigs without diabetes. In conclusion, reference values for CRP, PMAP, haptoglobin, SAA, PAGP and albumin were established for male and female Göttingen minipigs of different ages. These APP were influenced by age and sex, underlining the importance of considering these factors when designing and interpreting studies including aspects of inflammation. In addition, an APP response was verified after both acute and chronic stimuli. Abbreviations: APP, acute-phase proteins; APR, acute-phase response; CRP, C-reactive protein; HFD, high-fat diet; HFD+D, high fat diet + diabetes; PAGP, porcine α1 acid glycoprotein; PMAP, pig major acute-phase protein; SAA, serum amyloid AInflammation is involved in a number of important and increasingly widespread human diseases, including inflammatory bowel diseases, cancers, infections, metabolic diseases like obesity and diabetes, and cardiovascular diseases like atherosclerosis.^{1,5,7,11,20,41} The systemic response to inflammation is the acute-phase response (APR) which, together with innate immune responses, prevents infection, clears pathogens, and contributes to inflammation resolution and the healing process. The APR has been extensively described in humans^10,22 and other mammals,^8,14,29,31 and in all cases, it is regulated by cytokines including IL6 and TNFα.^21,30 The APR is activated by many different stimuli, including trauma, infection, stress, neoplasia, and inflammatory stimuli, resulting in significant changes in the circulating concentrations of the so-called acute-phase proteins (APP). The APP are synthetized primarily by the liver and can be divided into positive and negative APP depending on whether their concentration in plasma increases (positive) or decreases (negative) in response to a stimulus.¹⁰ In addition, they can be divided into major and minor APP, depending on the magnitude of their concentration change after a given stimulus.²² Because the concentrations of the APP change in response to a given stimulus, their serum or plasma levels can be used diagnostically as biomarkers of disease severity and progression or to evaluate the effect of various interventions.^8,14,31 The APP show different kinetics after a stimulus, with C-reactive protein (CRP) and serum amyloid A (SAA) displaying rapid increases and normalization after the stimulus has been removed, whereas haptoglobin shows a later and more prolonged response.^10,31 The APR may be transient and revert to normal with recovery, or it can persist, as during chronic conditions.²¹ Importantly, APP and their kinetics differ somewhat between species.³¹To further elucidate the involvement of inflammation in human diseases, accurate animal models of inflammation, including species validated biomarkers of inflammation, are needed. Mouse models are commonly used in many research areas, but their response to several different inflammatory conditions is not comparable to that of humans, and therefore the predictive validity of these models may be limited.³⁹ Pigs are highly comparable to humans with respect to anatomy and physiology,⁴⁴ and their APR to various stimuli has been described.^14,23,26 In general, the APR and the resulting changes in APP seem to be very similar in pigs compared with humans, with CRP, haptoglobin, and SAA being major positive APP and albumin being a negative APP.¹⁴ In humans, α1-acid glycoprotein (AGP) is a positive APP but has been reported to either increase,¹⁷ remain unchanged^23,45 or to decrease¹² in pigs, depending on the stimulus investigated. The concentrations of some of the major APP characterized in domestic pigs show significant effects of age and sex.^32,34 In addition to age and sex effects, significant differences in APP between herds have been observed, most likely reflecting different pathogenic pressures in the different herds.³² Furthermore, some indications exist for possible interbreed differences in APP concentrations, although this possibility has not been investigated in detail.¹²Minipigs are especially relevant in biomedical research, given their smaller size and well-defined microbiology and genetics.⁴ Göttingen minipigs are a useful model for several conditions involving inflammation and the APR, including infection,² obesity,¹⁹ diabetes²⁴ and atherosclerosis,¹⁸ and different APP have already been used as biomarkers in some of these models.² Therefore, existing data suggest that APP commonly applied in human medicine could be relevant in Göttingen minipigs as well. However, the APR and reference values of APP, including the potential influence of age and sex indicated in other studies, have not been investigated systematically in this breed.^12,32,34The objective of the current study was to establish reference values of selected APP in normal Göttingen minipigs, including evaluation of the possible effects of age and sex. In addition, the effects of housing condition and acute and chronic inflammatory stimuli were assessed.