scholarly journals Sex pheromones in amphibians: a review 

2012 ◽  
Vol 50 (No. 9) ◽  
pp. 385-389 ◽  
Author(s):  
J. Rajchard
Keyword(s):  
Sex Pheromones ◽  
Sexual Relationships ◽  
Arginine Vasotocin ◽  
Biologically Active ◽  
Amino Acid Residues ◽  
Courtship Pheromone ◽  
Skin Glands ◽  
Inactive Form ◽  
Female Attraction ◽  
Pheromonal Activity

Amphibians are interesting animals, very often kept by aquarists and vivarists. Their ability of intraspecific chemical signalization belongs to very interesting biological features. The skin glands of anurans secrete various biologically active compounds. The pheromones are peptides consisting of various numbers of amino acid residues and their synthesis is regulated by hormones (e.g. prolactin and androgens). Similarly, the responsiveness of the vomeronasal epithelium to some of these compounds is enhanced by some hormonal substances (prolactin and oestrogen). Hypophyseal hormones, arginine vasotocin and gonadotropin-releasing hormone are involved in the humoral regulation of pheromone discharge. The storage of some compounds with pheromonal activity in a biologically inactive form was also proved. The pheromones have an important role in sexual relationships. These chemosignals increase female receptivity and are probably involved in the mate choice. The courtship pheromone signals may be conserved across related species. Chemosignals play an important role in female attraction and/or territorial announcement. In addition to sex pheromones, various neuropeptides, antimicrobial and other biologically active peptides were found in skin glands of these amphibians. The infochemical system can be disturbed by a chemical influence in the environment.

Analogues of the cholecystokinin octapeptide modified in the central part of the molecule

1991 ◽  
Vol 56 (9) ◽  
pp. 1963-1970 ◽  
Author(s):  
Jan Hlaváček ◽  
Václav Čeřovský ◽  
Jana Pírková ◽  
Pavel Majer ◽  
Lenka Maletínská ◽  
...  
Keyword(s):  
Amino Acid ◽  
Biological Activities ◽  
Point Of View ◽  
Biologically Active ◽  
Side Chain ◽  
Amino Acid Residues ◽  
Cholecystokinin Octapeptide ◽  
Biological Tests ◽  
Biological Potency ◽  
Biologically Active Conformation

In a series of analogues of the cholecystokinin octapeptide (CCK-8) the amino acid residues were gradually modified by substituting Gly by Pro in position 4, Trp by His in position 5, Met by Cle in position 6, or the Gly residue was inserted between Tyr and Met in positions 2 and 3 of the peptide chain, and in the case of the cholecystokinin heptapeptide (CCK-7) the Met residues were substituted by Nle or Aib. These peptides were investigated from the point of view of their biological potency in the peripheral and central region. From the results of the biological tests it follows that the modifications carried out in these analogues and in their Nα-Boc derivatives mean a suppression of the investigated biological activities by 2-3 orders of magnitude (at a maximum dose of the tested substance of 2 . 10-2 mg per animal).This means that a disturbance of the assumed biologically active conformation of CCK-8, connected with a considerable decrease of the biological potency of the molecule, takes place not only after introduction of the side chain into its centre (substitution of Gly4), but also after the modification of the side chains of the amino acids or by extension of the backbone in further positions around this central amino acid.

Synthesis of a Biologically Active Nonadecapeptide Corresponding to the First Nineteen Amino Acid Residues of Adrenocorticotropins1a

1961 ◽  
Vol 83 (21) ◽  
pp. 4449-4457 ◽  
Author(s):  
Choh Hao Li ◽  
Johannes Meienhofer ◽  
Eugen Schnabel ◽  
David Chung ◽  
Tung-Bin Lo ◽  
...  
Keyword(s):  
Amino Acid ◽  
Biologically Active ◽  
Amino Acid Residues

The importance of linkers in the structure of PSMA ligands

2021 ◽  
Vol 28 ◽  
Author(s):  
Anastasia A. Uspenskaya ◽  
Ekaterina A. Nimenko ◽  
Aleksei E. Machulkin ◽  
Elena K. Beloglazkina ◽  
Alexander G. Majouga
Keyword(s):  
Prostate Cancer ◽  
Solid Phase ◽  
Biologically Active ◽  
Modern World ◽  
Synthesis Methods ◽  
Amino Acid Residues ◽  
Ongoing Research ◽  
Phase Synthesis ◽  
Diagnose Prostate Cancer ◽  
Positive Effect

: Cancer is one of the leading social problems of the modern world. Today prostate cancer is the second leading cause of cancer deaths among men. Targeted drug delivery is widely used to treat and diagnose prostate cancer. Conjugates selectively binding to prostate specific membrane antigen based on urea ligands are being actively developed against this disease. The linker has a significant influence on the biological activity of such conjugates. The linker performs a large number of functions, and its modification is one of the key methods of creating the best pharmacological profile. This review aims to discuss and analyze the main approaches to the method of introduction and synthesis of linkers for this type of conjugates without a description of the influence of biologically active molecules, as well as to establish the key modification methods that have a significant role on the structure-activity relationship. For this purpose, a review of the current scientific literature was performed, both for the conjugates under development and for those already undergoing clinical trials. It was found that the optimal structure is a linker containing an aliphatic fragment near the vector-molecule (n(CH2) = 3-6), followed by a polypeptide chain consisting of 2 to 4 amino acid residues. The presence of a Phe-Phe dipeptide chain or the introduction of negatively charged groups also has a positive effect. Ongoing research in this field helps to establish the accurate effect of each linker fragment, and the development of solid-phase synthesis methods makes it much easier to achieve this goal.

scholarly journals Primary Structure Analysis of Antifungal Peptides from Cultivated and Wild Cereals

Plants ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 74 ◽  
Author(s):  
Eugene Rogozhin ◽  
Dmitry Ryazantsev ◽  
Alexey Smirnov ◽  
Sergey Zavriev
Keyword(s):  
Antimicrobial Activity ◽  
Amino Acid ◽  
Antifungal Activity ◽  
Antimicrobial Peptides ◽  
Structure Analysis ◽  
Primary Structure ◽  
Biologically Active ◽  
Amino Acid Residues ◽  
Wild Cereals ◽  
Determining Factor

Cereal-derived bioactive peptides with antimicrobial activity have been poorly explored compared to those from dicotyledonous plants. Furthermore, there are a few reports addressing the structural differences between antimicrobial peptides (AMPs) from cultivated and wild cereals, which may shed light on significant varieties in the range and level of their antimicrobial activity. We performed a primary structure analysis of some antimicrobial peptides from wild and cultivated cereals to find out the features that are associated with the much higher antimicrobial resistance characteristic of wild plants. In this review, we identified and analyzed the main parameters determining significant antifungal activity. They relate to a high variability level in the sequences of C-terminal fragments and a high content of hydrophobic amino acid residues in the biologically active defensins in wild cereals, in contrast to AMPs from cultivated forms that usually exhibit weak, if any, activity. We analyzed the similarity of various physicochemical parameters between thionins and defensins. The presence of a high divergence on a fixed part of any polypeptide that is close to defensins could be a determining factor. For all of the currently known hevein-like peptides of cereals, we can say that the determining factor in this regard is the structure of the chitin-binding domain, and in particular, amino acid residues that are not directly involved in intermolecular interaction with chitin. The analysis of amino acid sequences of alpha-hairpinins (hairpin-like peptides) demonstrated much higher antifungal activity and more specificity of the peptides from wild cereals compared with those from wheat and corn, which may be associated with the presence of a mini cluster of positively charged amino acid residues. In addition, at least one hydrophobic residue may be responsible for binding to the components of fungal cell membranes.

scholarly journals In VivoEffects of Leptin-Related Synthetic Peptides on Body Weight and Food Intake in Female ob/obMice: Localization of Leptin Activity to Domains Between Amino Acid Residues 106–140*

Endocrinology ◽  
1997 ◽  
Vol 138 (4) ◽  
pp. 1413-1418 ◽  
Author(s):  
Patricia Grasso ◽  
Matthew C. Leinung ◽  
Stacy P. Ingher ◽  
Daniel W. Lee
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Amino Acid ◽  
Food Intake ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Amino Acid Residues ◽  
Inactive Form ◽  
In Vivo Effects

Abstract In C57BL/6J ob/ob mice, a single base mutation of the ob gene in codon 105 results in the replacement of arginine by a premature stop codon and production of a truncated inactive form of leptin. These observations suggest that leptin activity may be localized, at least in part, to domains distal to amino acid residue 104. To investigate this possibility, we synthesized six overlapping peptide amides corresponding to residues 106–167 of leptin, and examined their effects on body weight and food intake in female C57BL/6J ob/ob mice. When compared with vehicle-injected control mice, weight gain by mice receiving 28 daily 1-mg ip injections of LEP-(106–120), LEP-(116–130), or LEP-(126–140) was significantly (P < 0.01) reduced with no apparent toxicity. Weight gain by mice receiving LEP-(136–150), LEP-(146–160), or LEP-(156–167) was not significantly different from that of vehicle-injected control mice. The effects of LEP-(106–120), LEP-(116–130), or LEP-(126–140) were most pronounced during the first week of peptide treatment. Within 7 days, mice receiving these peptides lost 12.3%, 13.8%, and 9.8%, respectively, of their initial body weights. After 28 days, mice given vehicle alone, LEP-(136–150), LEP-(146–160), or LEP-(156–167) were 14.7%, 20.3%, 25.0%, and 24.8% heavier, respectively, than they were at the beginning of the study. Mice given LEP-(106–120) or LEP-(126–140) were only 1.8% and 4.2% heavier, respectively, whereas mice given LEP-(116–130) were 3.4% lighter. Food intake by mice receiving LEP-(106–120), LEP-(116–130), or LEP-(126–140), but not by mice receiving LEP-(136–150), LEP-(146–160), or LEP-(156–167), was reduced by 15%. The results of this study indicate 1) that leptin activity is localized, at least in part, in domains between residues 106–140; 2) that leptin-related peptides have in vivo effects similar to those of native leptin; and 3) offer hope for development of peptide analogs of leptin having potential application in human or veterinary medicine.

New Antibiotic Uperin Peptides From the Dorsal Glands of the Australian Toadlet Uperoleia mjobergii

1996 ◽  
Vol 49 (12) ◽  
pp. 1325 ◽  
Author(s):  
AM Bradford ◽  
JH Bowie ◽  
MJ Tyler ◽  
JC Wallace
Keyword(s):  
Mass Spectrometry ◽  
Amino Acid ◽  
Related Species ◽  
Antibiotic Activity ◽  
Amino Acid Sequences ◽  
The Other ◽  
Cationic Peptides ◽  
Amino Acid Residues ◽  
Skin Glands ◽  
Edman Sequencing

The dorsal glandular extract of the toadlet Uperoleia mjobergii contains more than 20 peptides. We report the amino acid sequences of the seven major peptides: these were determined by a combination of mass spectrometry and automated Edman sequencing. Three of these peptides have 19 amino acid residues and belong to the uperin 2 group of peptides [e.g. uperin 2.6, Gly Ile Leu Asp Ile Ala Lys Lys Leu Val Gly Gly Ile Arg Asn Val Leu Gly Ile (OH)], while the other four have 17 residues and are classified as uperins 3 [e.g. Uperin 3.4, Gly Val Gly Asp Leu Ile Arg Lys Ala Val Ala Ala Ile Lys Asn Ile Val (NH2)]. Several of these cationic peptides have been synthesized in order for bioassays to be carried out: they show significant antibiotic activity against a range of Gram-positive microorganisms. A major skin peptide from the related species Uperoleia inundata is a powerful neuropeptide named uperin 1.1 ([Ala2] uperolein ): no corresponding neuropeptide is detected in the skin glands of Uperoleia mjobergii.

scholarly journals Natural variation in the HAN1 gene confers chilling tolerance in rice and allowed adaptation to a temperate climate

2019 ◽  
Vol 116 (9) ◽  
pp. 3494-3501 ◽  
Author(s):  
Donghai Mao ◽  
Yeyun Xin ◽  
Yongjun Tan ◽  
Xiaojie Hu ◽  
Jiaojiao Bai ◽  
...  
Keyword(s):  
Chilling Tolerance ◽  
Rice Cultivation ◽  
Biologically Active ◽  
Temperate Climate ◽  
Inactive Form ◽  
Natural Variants ◽  
Specific Allele ◽  
Trait Locus ◽  
Chilling Response ◽  
Staple Crop

Rice (Oryza sativa L.) is a chilling-sensitive staple crop that originated in subtropical regions of Asia. Introduction of the chilling tolerance trait enables the expansion of rice cultivation to temperate regions. Here we report the cloning and characterization of HAN1, a quantitative trait locus (QTL) that confers chilling tolerance on temperate japonica rice. HAN1 encodes an oxidase that catalyzes the conversion of biologically active jasmonoyl-L-isoleucine (JA-Ile) to the inactive form 12-hydroxy-JA-Ile (12OH-JA-Ile) and fine-tunes the JA-mediated chilling response. Natural variants in HAN1 diverged between indica and japonica rice during domestication. A specific allele from temperate japonica rice, which gained a putative MYB cis-element in the promoter of HAN1 during the divergence of the two japonica ecotypes, enhances the chilling tolerance of temperate japonica rice and allows it to adapt to a temperate climate. The results of this study extend our understanding of the northward expansion of rice cultivation and provide a target gene for the improvement of chilling tolerance in rice.

Bovine growth hormone fragment (1–133) has in-vitro somatomedin-like activity

1983 ◽  
Vol 96 (2) ◽  
pp. 195-199 ◽  
Author(s):  
J. P. Liberti ◽  
L. A. Durham
Keyword(s):  
Growth Hormone ◽  
Amino Acid ◽  
Costal Cartilage ◽  
Peptide Bond ◽  
Biologically Active ◽  
The Other ◽  
Bovine Growth Hormone ◽  
Amino Acid Residues ◽  
In Vitro Uptake

Thrombin digestion of bovine growth hormone (1–191) resulted in cleavage of the peptide bond between amino acid residues 133 and 134. Native growth hormone and purified peptides (1–133) and (134–191) were assayed for somatomedin-like activity. Peptide (1–133), ranging in concentration from 0·15–15 nmol/l, stimulated in-vitro uptake of [3H]thymidine by rat costal cartilage. None of the other peptides was biologically active.

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