A century of regulatory peptides: From discovery to function

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Medicinal plants from the Yanesha (Peru): Evaluation of the leishmanicidal and antimalarial activity of selected extracts

Aim of the study

Ninety-four ethanolic extracts of plants used medicinally by the Yanesha, an Amazonian Peruvian ethnic group, for affections related to leishmaniasis and malaria were screened in vitro against Leishmania amazonensis amastigotes and against a Plasmodium falciparum chloroquine resistant strain.

Materials and methods

The viability of Leishmania amazonensis amastigote stages was assessed by the reduction of tetrazolium salt (MTT) while the impact on Plasmodium falciparum was determined by measuring the incorporation of radio-labelled hypoxanthine.

Results and conclusions

Six plant species displayed good activity against Plasmodium falciparum chloroquine resistant strain (IC₅₀ < 10 μg/ml): a Monimiaceae, Siparuna aspera (Ruiz & Pavon), A. DC., two Zingiberaceae, Renealmia thyrsoidea (Ruiz & Pavon) Poepp. & Endl. and Renealmia alpinia (Rottb.), two Piperaceae (Piper aduncum L. and Piper sp.) and the leaves of Jacaranda copaia (Aubl.) D. Don (Bignoniaceae).Eight species displayed interesting leishmanicidal activities (IC₅₀ < 10 μg/ml): Carica papaya L. (Caricaceae), Piper dennisii Trel (Piperaceae), Hedychium coronarium J. König (Zingiberaceae), Cestrum racemosum Ruiz & Pav. (Solanaceae), Renealmia alpinia (Rottb.) Zingiberaceae, Lantana sp. (Verbenaceae), Hyptis lacustris A. St.-Hil. ex Benth. (Lamiaceae) and Calea montana Klat. (Asteraceae). Most of them are used against skin affections by Yanesha people.Results are discussed herein, according to the traditional use of the plants and compared with data obtained from the literature.     

Neonatal exposure to monosodium glutamate induces morphological alterations in suprachiasmatic nucleus of adult rat

Neonatal exposure to monosodium glutamate (MSG) induces circadian disorders in several physiological and behavioural processes regulated by the suprachiasmatic nucleus (SCN). The objective of this study was to evaluate the effects of neonatal exposure to MSG on locomotor activity, and on morphology, cellular density and expression of proteins, as evaluated by optical density (OD), of vasopressin (VP)‐, vasoactive intestinal polypeptide (VIP)‐ and glial fibrillary acidic protein (GFAP)‐immunoreactive cells in the SCN. Male Wistar rats were used: the MSG group was subcutaneously treated from 3 to 10 days of age with 3.5 mg/g/day. Locomotor activity was evaluated at 90 days of age using ‘open‐field’ test, and the brains were processed for immunohistochemical studies. MSG exposure induced a significant decrease in locomotor activity. VP‐ and VIP‐immunoreactive neuronal densities showed a significant decrease, while the somatic OD showed an increase. Major axes and somatic area were significantly increased in VIP neurons. The cellular and optical densities of GFAP‐immunoreactive sections of SCN were significantly increased. These results demonstrated that newborn exposure to MSG induced morphological alterations in SCN cells, an alteration that could be the basis for behavioural disorders observed in the animals.     

Inhibition of NF-κB Signaling Reduces Virus Load and Gammaherpesvirus-Induced Pulmonary Fibrosis

IgA nephropathy (IgAN) and Henoch-Schönlein purpura (HSP) are diseases characterized by IgA deposits in the kidney and/or skin. Both may arise after upper respiratory tract infections, but the pathogenic mechanisms governing these diseases remain unclear. Patients with IgAN (n = 16) and HSP (n = 17) were included in this study aimed at examining whether IgA-binding M proteins of group A streptococci could be involved. As M proteins vary in sequence, the study focused on the IgA-binding-region (IgA-BR) of three different M proteins: M4, M22, and M60. Renal tissue from IgAN and HSP patients and skin from HSP patients were examined for deposits of streptococcal IgA-BR by immunohistochemistry and electron microscopy using specific antibodies, and a skin sample from a HSP patient was examined by mass spectrometry. IgA-BR deposits were detected in 10/16 IgAN kidneys and 7/13 HSP kidneys. Electron microscopy demonstrated deposits of IgA-BRs in the mesangial matrix and glomerular basement membrane, which colocalized with IgA. Skin samples exhibited IgA-BR deposits in 4/5 biopsies, a result confirmed by mass spectrometry in one patient. IgA-BR deposits were not detected in normal kidney and skin samples. Taken together, these results demonstrate IgA-BR from streptococcal M proteins in patient tissues. IgA-BR, would on gaining access to the circulation, encounter circulatory IgA and form a complex with IgA-Fc that could deposit in tissues and contribute to the pathogenesis of IgAN and HSP.Tissue deposits containing IgA characterize IgA nephropathy (IgAN) and Henoch-Schönlein purpura (HSP), two conditions affecting kidney function. IgAN is the most common primary glomerulonephritis worldwide. Its predominant clinical feature is episodic macroscopic hematuria usually coinciding with upper respiratory tract infections. Symptoms may, however, vary from microscopic hematuria to a severe nephritic-nephrotic syndrome. End-stage kidney disease occurs in 30% to 40% of patients within 20 years. Histopathologically IgAN is characterized by mesangial cell proliferation and in progressive cases crescent formation as well as glomerular sclerosis, interstitial fibrosis, and tubular atrophy. Ultramorphologic findings show mesangial deposits of immune complexes containing predominantly IgA.^1,2HSP is the most common form of vasculitis in childhood. It may affect many organs, but usually presents as skin lesions, varying from purpura to bullous intradermal bleedings, arthritis, gastrointestinal involvement with pain and/or bleeding. Renal involvement occurs in up to 50% of cases³ and is known as Henoch-Schönlein nephropathy (HSN). HSN may manifest as microscopic or macroscopic hematuria as well as glomerulonephritis or nephrotic syndrome. Approximately 20% of HSN cases will develop renal failure.⁴ The histopathological lesion termed leukocytoclastic vasculitis is characterized by inflammation of small vessels with perivascular polymorphonuclear leukocyte and mononuclear cell infiltrates. Immune deposits in affected organs contain IgA, and renal pathology resembles that seen in IgAN.^1,3The IgA mesangial deposits in kidneys of patients with IgAN and HSP are primarily composed of galactose-deficient IgA1.^5,6,7 The mechanism by which under-glycosylated IgA1 deposits in the mesangium, possibly in complex with IgG,^8,9 has not been determined. Environmental antigens have been proposed to contribute to the disease but have not been consistently associated with mesangial deposits.⁹ Although the etiology of IgAN and HSP is unclear, these diseases are often preceded by infections, primarily of the upper respiratory tract, and an infectious agent has therefore been suspected. There is circumstantial evidence for involvement of group A streptococcus (GAS, Streptococcus pyogenes),^{10,11,12,13,14,15} but infections with other bacteria^16,17 as well as viruses¹⁸ have been implicated as well.In this study we hypothesized that GAS infection could trigger IgAN and/or HSN, because GAS is a very common cause of upper respiratory tract infection, and because many GAS strains bind IgA-Fc.^19,20,21 The ability of a GAS strain to bind human IgA results from the presence of an IgA-binding region (IgA-BR) in the surface-localized M protein.^22,23 The fibrillar M protein, which is a major virulence factor of GAS, varies in sequence between strains²⁴ allowing classification of GAS isolates into more than 120 M serotypes.²⁵ The exact function of the IgA-BR in an M protein is not known, but there is evidence that it contributes to bacterial phagocytosis resistance.²⁶ The IgA-BR of an M protein represents a distinct domain that can be studied in isolated form, as a peptide that binds IgA.^27,28 Such IgA-binding peptides, designated Sap (streptococcal IgA-binding peptide), were used in the experiments described herein.To analyze whether IgA-binding streptococcal M proteins are present in affected tissues of patients with IgAN and/or HSP, and colocalize with IgA, we used antibodies to the IgA-BR of three different M proteins M4, M22, and M60. Of note, M4 and M22 are among the most common serotypes of clinical GAS isolates.²⁹ As the IgA-BRs of different M proteins vary extensively in sequence,^22,23 the use of antibodies to three different serotypes enhanced our chances to detect tissue deposition of an IgA-BR.     

An in vivo role for Trypanosoma cruzi calreticulin in antiangiogenesis

Angiogenesis leads to neovascularization from existing blood vessels. It is associated with tumor growth and metastasis and is regulated by pro- and antiangiogenic molecules, some of them currently under clinical trials for cancer treatment. During the last few years we have cloned, sequenced and expressed a Trypanosoma cruzi calreticulin gene (TcCRT). Its product, TcCRT, a 45 kDa protein, is more than 50% identical to human CRT (HuCRT). TcCRT, present on the surface of trypomastigotes, binds both C1q and mannan binding lectin and inhibits the classical activation pathway of human complement. Since TcCRT is highly homologous to a functional antiangiogenic fragment from HuCRT (aa 120–180), recombinant (r) and native (n) TcCRT were tested in their antiangiogenic effects, in the chick embryonic chorioallantoid membrane (CAM) assay. Both proteins mediated highly significant antiangiogenic effects in the in vivo CAM assay. This effect was further substantiated in experiments showing that the plasmid construct pSecTag/TcCRT also displayed significant antiangiogenic properties, as compared to the empty vector. Most likely, the fact that antiangiogenic substances act preferentially on growing neoplasic tissues, but not on already established tumors, is due to their effects on emerging blood vessels. The results shown here indicate that TcCRT, like its human counterpart, has antiangiogenic properties. These properties may explain, at least partly, the reported antineoplasic effect of experimental T. cruzi infection.     

High‐frequency ventilation with the Dräger Babylog 8000plus: measuring the delivered frequency

Background: Ventilator frequency is one of the determinants of tidal volume delivery during high‐frequency ventilation. Clinicians increasingly use data on ventilator displays to inform their decisions. Aim: To measure the frequencies delivered by the Dräger Babylog 8000plus ventilator when used in high‐frequency mode. Methods: Ventilator waveforms using a test lung were recorded at the full range of settings 5–20 Hz using Spectra software at 1000 Hz. The changes in frequency produced by a 1‐ Hz change in set frequency were calculated. Actual and displayed frequencies were compared. Results: For settings up to 12 Hz, median (range) difference between set and delivered frequencies was 0 (?0.4 to +0.1) Hz. Above 12 Hz, delivered frequency varied by ?0.3 (?1.9 to +0.3) Hz. For 1‐ Hz changes in frequency settings, in the range 5–12 Hz, 1‐ Hz changes produced a change in delivered frequency of 1.0 (0.6–1.4) Hz. Above 12 Hz, the corresponding changes were 0.7 (0–2.9) Hz. The ventilator displays the set frequency during operation rather than the delivered frequency. Conclusion: At 12 Hz and below, the differences between set and delivered frequencies were relatively small compared with those at 13 Hz and higher. Above 13 Hz, the difference between set and delivered frequencies was up to 2.9 Hz. Some frequency setting changes did not result in a change in delivered frequency.     

Trypanosoma cruzi histone H1 is phosphorylated in a typical cyclin dependent kinase site accordingly to the cell cycle

Histone H1 of most eukaryotes is phosphorylated during the cell cycle progression and seems to play a role in the regulation of chromatin structure, affecting replication and chromosome condensation. In trypanosomatids, histone H1 lacks the globular domain and is shorter when compared with the histone of other eukaryotes. We have previously shown that in Trypanosoma cruzi, the agent of Chagas' disease, histone H1 is phosphorylated and this increases its dissociation from chromatin. Here, we demonstrate using mass spectrometry analysis that T. cruzi histone H1 is only phosphorylated at the serine 12 in the sequence SPKK, a typical cyclin-dependent kinase site. We also found a correlation between the phosphorylation state of histone H1 and the cell cycle. Hydroxyurea and lactacystin, which, respectively, arrest parasites at the G1/S and G2/M stages of the cell cycle, increased the level of histone H1 phosphorylation. Cyclin-dependent kinase-related enzymes TzCRK3, and less intensely the TzCRK1 were able to phosphorylate histone H1 in vitro. Histone H1 dephosphorylation was prevented by treating the parasites with okadaic acid but not with calyculin A. These findings suggest that T. cruzi histone H1 phosphorylation is promoted by cyclin dependent kinases, present during S through G2 phase of the cell cycle, and its dephosphorylation is promoted by specific phosphatases.     

Antimicrobial Activities of Skincare Preparations from Plant Extracts

In this study, Tithonia diversifolia Helms. (A Gray), Aloe secundiflora (Miller) and Azadirachta indica (A. Juss) plant extracts were used to make herbal soaps while Thevetia peruviana (Schum) seed oil was used to make a herbal lotion for skincare. The soaps were tested for the growth inhibition of Escherichia coli, and Candida albicans. The lotion was evaluated against Staphylococcus aureus and E.coli. Although Tithonia diversifolia soap exhibited the highest inhibitory effect on the test bacterial strains, it had the least inhibition against C. albicans. Results from this study indicated that the ‘Tithonia diversifolia’ soap would have superior skin protection against the tested bacteria but would offer the least skin protection against C. albicans. The herbal lotion inhibited S. aureus and E. coli in a concentration dependent manner, however, the inhibitory effect was more pronounced on S. aureus.