dark pigmentation
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Author(s):  
Noriyoshi Akiyama ◽  
Shoma Sato ◽  
Kentaro M Tanaka ◽  
Takaomi Sakai ◽  
Aya Takahashi

Abstract The spatiotemporal regulation of gene expression is essential to ensure robust phenotypic outcomes. Pigmentation patterns in Drosophila are determined by pigments biosynthesized in the developing epidermis and the cis-regulatory elements (CREs) of the genes involved in this process are well-characterized. Here we report that the known primary epidermal enhancer (priEE) is dispensable for the transcriptional activation of ebony (involved in light-colored pigment synthesis) in the developing epidermis of D. melanogaster. The evidence was obtained by introducing an approximately 1 kbp deletion at the priEE by genome editing. The effect of the priEE deletion on pigmentation and on the endogenous expression pattern of a mCherry-fused ebony allele was examined in the abdomen. The expression levels of the mCherry-fused ebony in the priEE-deleted strains were slightly higher than that of the control strain, indicating that the sequences outside the priEE have an ability to drive an expression of this gene in the epidermis. Interestingly, the priEE deletion resulted in a derepression of this gene in the dorsal midline of the abdominal tergites, where dark pigmentation is present in the wild-type individuals. This indicated that the priEE fragment contains a silencer. Furthermore, the endogenous expression pattern of ebony in the two additional strains with partially deleted priEE revealed that the silencer resides within a 351-bp fragment in the 5' portion of the priEE. These results demonstrated that deletion assays combined with reporter assays are highly effective in detecting the presence of positively and negatively regulating sequences within and outside the focal CREs.


2021 ◽  
Vol 9 (2) ◽  
pp. 542-549
Author(s):  
Dewi Hidayati ◽  
Moh. Ulya Alfarisy ◽  
Khairunissa Khairunissa ◽  
Fredy Kurniawan ◽  
Endry Nugroho Prasetyo ◽  
...  

Fish skin is the potential gelatin source since the increase of the demand for the halal food due to the religious consideration. The yield of gelatin obtained from connective tissue of animal skin greatly affected by the extraction process and age of the animals that used as raw material. Research about the potential of the Pangasius hypophthalmus (striped catfish) skin as halal gelatin source have been developing. However, there was no information about the correlation between the length of striped catfish that representing age with the gelatin content. Here we optimize the gelatin extraction method from striped catfish skin with different length body size (sub adult and adult size) using statistical analysis of Placket Burman Design. We performed preliminary study to determine the variables used in the main study. We used 9 variables in the extraction process and analyzed the p-value of each variable. According to this analysis, three variables with the lowest p-values were selected: temperature (p=0.000); soaking time in alkali solution (p=0.055) and soaking time in acid solution (p=0.244). Range value of selected variables were determined according to the related previous studies. Results from our study showed that the maximum yield of sub adult and adult were obtained when we used 70 °C as temperature of extraction, i.e. 37.42% and 30.31%, respectively. In general, sub adult striped catfish have higher yield than the adult one at the temperature of 40 and 70 °C. However, the gelatin yielded from extraction process temperature of ≥70 °C exhibited dark pigmentation, while the gelatin that obtained with temperature treatment of ≤ 55°C showed less pigmentation. The gelatin yielded from sub adult striped catfish showed more pigmentation than the adult one. We suggested for process of extraction both size of striped catfish should be at 55°C, since it showed higher yield extraction with less pigmentation.


2021 ◽  
pp. 689-694
Author(s):  
Yuichiro Hirai ◽  
Hideki Mori ◽  
Ai Fujimoto

Pseudomelanosis duodeni is a rare condition characterized by the endoscopic appearance of diffuse dark pigmentation of the duodenal mucosa. It is typically seen in older women and has been reported to be associated with hypertension, chronic renal disease, diabetes mellitus, gastrointestinal hemorrhage, and the use of medications such as oral iron, furosemide, thiazide, hydralazine, and propranolol. We present a case of pseudomelanosis duodeni appearing after 2 years of oral iron therapy in an 85-year-old woman. Although oral iron supplementation seemed the strongest possible etiology, our patient had multiple comorbidities and was on other medications that have been described as associations. The majority of individuals taking oral iron or under these clinical conditions do not develop this entity; some other factors in patients may be responsible for its occurrence.


Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 485
Author(s):  
Anna Łubek ◽  
Martin Kukwa ◽  
Bogdan Jaroszewicz ◽  
Patryk Czortek

Current trends emphasize the importance of the examination of the functional composition of lichens, which may provide information on the species realized niche diversity and community assembly processes, thus enabling one to understand the specific adaptations of lichens and their interaction with the environment. We analyzed the distribution and specialization of diverse morphological, anatomical and chemical (lichen secondary metabolites) traits in lichen communities in a close-to-natural forest of lowland Europe. We considered these traits in relation to three levels of forest ecosystem organization: forest communities, phorophyte species and substrates, in order to recognize the specialization of functional traits to different levels of the forest complexity. Traits related to the sexual reproduction of mycobionts (i.e., ascomata types: lecanoroid apothecia, lecideoid apothecia, arthonioid apothecia, lirellate apothecia, stalked apothecia and perithecia) and asexual reproduction of mycobionts (pycnidia, hyphophores and sporodochia) demonstrated the highest specialization to type of substrate, tree species and forest community. Thallus type (foliose, fruticose, crustose and leprose thalli), ascospore dark pigmentation and asexual reproduction by lichenized diaspores (soredia and isidia) revealed the lowest specialization to tree species and substrate, as well as to forest community. Results indicate that lichen functional trait assemblage distribution should not only be considered at the level of differences in the internal structure of the analyzed forest communities (e.g., higher number of diverse substrates or tree species) but also studied in relation to specific habitat conditions (insolation, moisture, temperature, eutrophication) that are characteristic of a particular forest community. Our work contributes to the understanding of the role of the forest structure in shaping lichen functional trait composition, as well as enhancing our knowledge on community assembly rules of lichen species.


Zootaxa ◽  
2021 ◽  
Vol 4926 (1) ◽  
pp. 26-42
Author(s):  
MARK O’SHEA ◽  
STEPHEN J. RICHARDS

We describe a new species of groundsnake of the genus Stegonotus (Colubridae) from the Purari River basin in Gulf Province, Papua New Guinea. The new species can be most readily distinguished from all other New Guinean Stegonotus by its unique dorsal colour pattern which consists of a dark head and creamy-white anterior one third to two thirds of the body, grading into increasingly dense dark pigmentation on the posterior of the body and tail. It is most similar to S. iridis from the Raja Ampat Archipelago off western New Guinea, but that species has a different pattern of pigmentation dorsally, has a lower ventral scale count (198–211 vs. 229–239), and exhibits a different temporal scale arrangement. The description of S. aplini sp. nov. brings to fourteen the number of Stegonotus species described from New Guinea. A dichotomous key to described species in the New Guinea region is provided. 


2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Fazleenah Hussain ◽  
Dushyanth Gnanappiragasam ◽  
Freida Shaffrali

Abstract Background Chemotherapy medications are reported to cause discoloration of the nails known as melanonychia. Depending on the nail structure affected and the severity of the insult, the clinical features can be variable. There are a great deal of unreported cases of pigmentary nail changes associated with chemotherapy treatment. By sharing our knowledge, we hope to raise the awareness of these nail changes amongst clinicians. Early recognition is crucial to allay anxiety among patients and avoid any unnecessary investigations. Case presentation We present a case of 36-year-old woman of south Asian origin, who developed dark pigmentation in the left thumb nail during neoadjuvant chemotherapy with 5-fluorouracil, epirubicin, cyclophosphamide, and docetaxel (FEC-D) for triple negative breast cancer. Upon examination, the left thumb nail pigmentation was strikingly linear, uniform, and well demarcated extending from proximal nail fold to free margin. Despite the reassuring clinical features, the patient was understandably anxious that this could be a presentation of acral melanoma and was referred to the plastic surgeons for a nail matrix biopsy. Biopsy reassuringly was reported as melanosis and a diagnosis of striate melanonychia was made. The patient was discharged after 2-year follow-up. Conclusion Chemotherapy medications have improved survival rates and patient outcomes. It is important for clinicians to be aware of the association of melanonychia with certain chemotherapy medications to reduce anxiety and allow successful management of these patients without delay. Striate melanonychia in this patient was felt most likely due to the synergistic effect of chemotherapy drugs compounded with racial predisposition. Chemotherapy agents most likely to have contributed include cyclophosphamide, docetaxel, and 5-fluorouracil.


Biology Open ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. bio056523
Author(s):  
Xin Huang ◽  
Sijia Wang ◽  
Li Jin ◽  
Yungang He

ABSTRACTHuman pigmentation is a highly diverse and complex trait among populations and has drawn particular attention from both academic and non-academic investigators for thousands of years. Previous studies detected selection signals in several human pigmentation genes, but few studies have integrated contribution from multiple genes to the evolution of human pigmentation. Moreover, none has quantified selective pressures on human pigmentation over epochs and between populations. Here, we dissect dynamics and differences of selective pressures during different periods and between distinct populations with new approaches. We use genotype data of 19 genes associated with human pigmentation from 17 publicly available datasets and obtain data for 2346 individuals of six representative population groups from across the world. Our results quantify the strength of natural selection on light pigmentation not only in modern Europeans (0.0259/generation) but also in proto-Eurasians (0.00650/generation). Our results also suggest that several derived alleles associated with human dark pigmentation may be under positive directional selection in some African populations. Our study provides the first attempt to quantitatively investigate the dynamics of selective pressures during different time periods in the evolution of human pigmentation.This article has an associated First Person interview with the first author of the article.


2020 ◽  
Vol 28 (2) ◽  
pp. 59-62
Author(s):  
Ugur Gonlugur ◽  
Tanseli Gonlugur ◽  
Sule Ozer

Bronchial anthracofibrosis has been defined as airway narrowing associated with dark pigmentation on bronchoscopy without an appropriate history of pneumoconiosis or smoking. We present a case of a 67-year-old, non-smoking female patient who was referred to our clinic for two years of persistent cough. Spirometry was within normal limits. Radiological evaluation showed right middle lobe atelectasis and positron emission tomography-positive mediastinal lymph nodes. Bronchoscopy revealed black airway discoloration and distortions. In conclusion, we propose monthly radiological controls before an invasive procedure in such cases if a strong suspicion of malignancy/tuberculosis is not present.


Author(s):  
Jan Pukalski ◽  
Natalia Marcol ◽  
Norbert Wolan ◽  
Przemysław Mieszko Płonka ◽  
Przemysław Ryszka ◽  
...  

Melanin occurrence in Plenodomus biglobosus was investigated using electron paramagnetic (spin) resonance (EPR, ESR) spectroscopy. The fungus was isolated from living and dead leaves of European ash (Fraxinus excelsior L.). Dark pigmentation of P. biglobosus mycelium in vitro, especially on the reverse, was observed. The black coloration intensified with the age of the culture and inspired us to check if the analyzed fungus species synthesizes melanin. Melanin contains unpaired electrons, thus, EPR spectroscopy was applied, as a specific technique, to verify its presence in P. biglobosus. The EPR spectrum of the mycelium showed a very strong melanin signal, revealing pheomelanin-like features. Thus, the black pigment of P. biglobosus was clearly identified as melanin. However, no melanin was detected in the apparently dark culture medium even when zinc (II) acetate was added to increase the sensitivity of detection. Pheomelanin has many unusual biological functions but it is not commonly found in fungi. Detection of this type of melanin in P. biglobosus, which can be both endophytic or pathogenic, suggests a closer examination of the potential role of this melanin in host-parasite interaction.


2020 ◽  
Vol 130 (3) ◽  
pp. 421-432 ◽  
Author(s):  
Horst Wilkens

Abstract The forces driving regression of biologically functionless traits remain disputed. There is ongoing debate regarding whether selection, as opposed to disuse and neutral mutations, is involved in this process. Cave species are of particular relevance for study in this regard because in continuous darkness all traits that depend on information from light, such as eyes, dark pigmentation and certain behaviours, abruptly lose their function. Recently, strong selection driving reduction has again been proposed, which relied on modelling analyses based on assumptions such as immigration of surface alleles into the cave forms or no fitness difference existing between Astyanax surface and cave fish. The validity of these assumptions, often applied to reject neutral processes in functionless traits, is questioned in this review. Morphological variation in a trait resulting from genetic variability is typical of biologically functionless traits and is particularly notable in phylogenetically young cave species. It is the most evident indicator of loss of selection, which normally enforces uniformity to guarantee optimal functionality. Phenotypic and genotypic variability in Astyanax cave fish eyes does not derive from genetic introgression by the surface form, but from regressive mutations not being eliminated by selection. This matches well with the principles of Kimura’s neutral theory of molecular evolution.


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