scholarly journals The Role of Photobionts as Drivers of Diversification in an Island Radiation of Lichen-Forming Fungi

2022 ◽  
Vol 12 ◽  
Author(s):  
Miguel Blázquez ◽  
Lucía S. Hernández-Moreno ◽  
Francisco Gasulla ◽  
Israel Pérez-Vargas ◽  
Sergio Pérez-Ortega

Speciation in oceanic islands has attracted the interest of scientists since the 19th century. One of the most striking evolutionary phenomena that can be studied in islands is adaptive radiation, that is, when a lineage gives rise to different species by means of ecological speciation. Some of the best-known examples of adaptive radiation are charismatic organisms like the Darwin finches of the Galapagos and the cichlid fishes of the great African lakes. In these and many other examples, a segregation of the trophic niche has been shown to be an important diversification driver. Radiations are known in other groups of organisms, such as lichen-forming fungi. However, very few studies have investigated their adaptive nature, and none have focused on the trophic niche. In this study, we explore the role of the trophic niche in a putative radiation of endemic species from the Macaronesian Region, the Ramalina decipiens group. The photobiont diversity was studied by Illumina MiSeq sequencing of the ITS2 region of 197 specimens spanning the phylogenetic breadth and geographic range of the group. A total of 66 amplicon sequence variants belonging to the four main clades of the algal genus Trebouxia were found. Approximately half of the examined thalli showed algal coexistence, but in most of them, a single main photobiont amounted to more than 90% of the reads. However, there were no significant differences in photobiont identity and in the abundance of ITS2 reads across the species of the group. We conclude that a segregation of the trophic niche has not occurred in the R. decipiens radiation.

2019 ◽  
Vol 127 (2) ◽  
pp. 479-492 ◽  
Author(s):  
Anna E Hiller ◽  
Michelle S Koo ◽  
Kari R Goodman ◽  
Kerry L Shaw ◽  
Patrick M O’Grady ◽  
...  

Abstract The role of the environmental niche in fostering ecological divergence during adaptive radiation remains enigmatic. In this study, we examine the interplay between environmental niche divergence and conservatism in the context of adaptive radiation on oceanic islands, by characterizing the niche breadth of four Hawaiian arthropod radiations: Tetragnatha spiders (Tetragnathidae Latreille, 1804), Laupala crickets (Gryllidae Otte, 1994), a clade of Drosophila flies (Drosophilidae Fallén, 1823) and Nesosydne planthoppers (Delphacidae Kirkaldy, 1907). We assembled occurrence datasets for the four lineages, modelled their distributions and quantified niche overlap. All four groups occupy the islands in distinct ways, highlighting the contrasting axes of diversification for different lineages. Laupala and Nesosydne have opposite environmental niche extents (broad and narrow, respectively), whereas Tetragnatha and Drosophila share relatively intermediate tolerances. Temperature constrains the distributions of all four radiations. Tests of phylogenetic signal suggest that, for Tetragnatha and Drosophila, closely related species exhibit similar environmental niches; thus, diversification is associated with niche conservatism. Sister species comparisons also show that populations often retain similar environmental tolerances, although exceptions do occur. Results imply that diversification does not occur through ecological speciation; instead, adaptive radiation occurs largely within a single environment.


2020 ◽  
Vol 2 (1) ◽  
pp. 73-90
Author(s):  
Ahmad Tohri ◽  
H. Habibuddin ◽  
Abdul Rasyad

This article discusses the Sasak people’s resistance against MataramKarangasem and Dutch colonial rulers in the 19th century in Lombok, Indonesia. It particularly focuses on Tuan Guru Umar Kelayu and his central role in the emergence of Sasak people’s resistance which transformed into Sasak physical revolution local and global imperialismcolonialism. Using the historical method, this article collected data through observation, in-depth interviews, and documentation. The data analysis involved the historical methods of heuristics, verification or criticism, interpretation, and historiography. The findings show that Sasak people’s resistance was not only caused by economic factors but also related to other factors such as social, cultural, and religious ones. Tuan Guru Umar Kelayu played a key role in the Sasak people’s resistance in that it was under his leadership and influence that the resistance transformed into a physical struggle against MataramKarangasem and Dutch colonialism as seen in Sakra War and Praya War which were led by his students and friends.


2020 ◽  
pp. 64-70
Author(s):  
Anastasiya Laknitskaya

Currently, one of the priority medical and social problems is the optimization of treatment methods for pyoderma associated with Streptococcus pyogenes — group A streptococcus (GAS). To date, the proportion of pyoderma, the etiological factor of which is Streptococcus pyogenes, is about 6 % of all skin diseases and is in the range from 17.9 to 43.9 % of all dermatoses. Role of the bacterial factor in the development of streptococcal pyoderma is obvious. Traditional treatment complex includes antibacterial drugs selected individually, taking into account the antibiotic sensitivity of pathognomonic bacteria, and it is not always effective. Currently implemented immunocorrection methods often do not take into account specific immunological features of the disease, the individual, and the fact that the skin performs the function of not only a mechanical barrier, but it is also an immunocompetent organ. Such an approach makes it necessary to conduct additional studies clarifying the role of factors of innate and adaptive immunity, intercellular mediators and antioxidant defense system, that allow to optimize the treatment of this pathology.


Author(s):  
Magdalena Zarzyka-Ryszka

The paper describes the past and present distribution of Colchicum autumnale in the vicinity of Cracow, highlights the role of Stanisław Dembosz (who published the first locality of C. autumnale near Igołomia in 1841). Gives information about the occurrence of C. autumnale in Krzeszowice in the 19th century (reported by Bronisław Gustawicz), presents new localities noted in 2012–2014 in meadows in the north-eastern part of the Puszcza Niepołomicka forest and adjacent area (between the Vistula and Raba rivers), and gives a locality found in Cracow in 2005 (no longer extant).


Author(s):  
D.R. Zhantiev

Аннотация В статье рассматривается роль и место Сирии (включая Ливан и Палестину) в системе османских владений на протяжении нескольких веков от османского завоевания до периода правления султана Абдул-Хамида II. В течение четырех столетий османского владычества территория исторической Сирии (Билад аш-Шам) была одним из важнейших компонентов османской системы и играла роль связующего звена между Анатолией, Египтом, Ираком и Хиджазом. Необходимость ежегодной организации хаджа с символами султанской власти и покровительства над святынями Мекки и Медины определяла особую стратегическую важность сирийских провинций Османской империи. Несмотря на ряд серьезных угроз во время общего кризиса османской государственности (конец XVI начало XIX вв.), имперскому центру удалось сохранить контроль над Сирией путем создания сдержек и противовесов между местными элитами. В XIX в. и особенно в период правления Абдул- Хамида II (18761909 гг.), сохранение Сирии под османским контролем стало вопросом существования Османской империи, которая перед лицом растущего европейского давления и интервенции потеряла большую часть своих владений на Балканах и в Северной Африке. Задача укрепления связей между имперским центром и периферией в сирийских вилайетах в последней четверти XIX в. была в целом успешно решена. К началу XX в. Сирия была одним из наиболее политически спокойных и прочно связанных со Стамбулом регионов Османской империи. Этому в значительной степени способствовали довольно высокий уровень общественной безопасности, развитие внешней торговли, рост образования и постепенная интеграция местных элит (как мусульман, так и христиан) в османские государственные и социальные механизмы. Положение Сирии в системе османских владений показало, что процесс ослабления и территориальной дезинтеграции Османской империи в эпоху реформ не был линейным и наряду с потерей владений и влияния на Балканах, в азиатской части империи в течение XIX и начала XX вв. происходил параллельный процесс имперской консолидации.Abstract The article examines the role and place of Greater Syria (including Lebanon and Palestine) in the system of Ottoman possessions over several centuries from the Ottoman conquest to the period of the reign of Abdul Hamid II. For four centuries of Ottoman domination, the territory of historical Syria (Bilad al-Sham) was one of the most important components in the Ottoman system and played the role of a link between Anatolia, Egypt, Iraq and Hijaz. The need to ensure the Hajj with symbols of Sultan power and patronage over the shrines of Mecca and Medina each year determined the special strategic importance of the Syrian provinces of the Ottoman Empire. Despite a number of serious threats during the general crisis of the Ottoman state system (late 16th early 19th centuries), the imperial center managed to maintain control over Syria by creating checks and balances between local elites. In the 19th century. And especially during the reign of Abdul Hamid II (18761909), keeping Syria under Ottoman control became a matter of existence for the Ottoman Empire, which, in the face of increasing European pressure and intervention, lost most of its possessions in the Balkans and North Africa. The task of strengthening ties between the imperial center and the periphery in Syrian vilayets in the last quarter of the 19th century was generally successfully resolved. By the beginning of the 20th century, Syria was one of the most politically calm and firmly connected with Istanbul regions of the Ottoman Empire. This was greatly facilitated by a fairly high level of public safety, the development of foreign trade, the growth of education and the gradual integration of local elites (both Muslims and Christians) into Ottoman state and social mechanisms. Syrias position in the system of Ottoman possessions clearly showed that the process of weakening and territorial disintegration of the Ottoman Empire during the era of reform was not linear, and along with the loss of possessions and influence in the Balkans, in the Asian part of the empire during the 19th and early 20th centuries there was a parallel process of imperial consolidation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yosuke Ono ◽  
Osamu Yoshino ◽  
Takehiro Hiraoka ◽  
Erina Sato ◽  
Akiko Furue ◽  
...  

AbstractIn endometriosis, M2 MΦs are dominant in endometriotic lesions, but the actual role of M2 MΦ is unclear. CD206 positive (+) MΦ is classified in one of M2 type MΦs and are known to produce cytokines and chemokines. In the present study, we used CD206 diphtheria toxin receptor mice, which enable to deplete CD206+ cells with diphtheria toxin (DT) in an endometriosis mouse model. The depletion of CD206+ MΦ decreased the total weight of endometriotic-like lesions significantly (p < 0.05). In the endometriotic-like lesions in the DT group, a lower proliferation of endometriotic cells and the decrease of angiogenesis were observed. In the lesions, the mRNA levels of VEGFA and TGFβ1, angiogenic factors, in the DT group significantly decreased to approximately 50% and 30% of control, respectively. Immunohistochemical study revealed the expressions of VEGFA and an endothelial cell marker CD31 in lesions of the DT group, were dim compared to those in control. Also, the number of TGFβ1 expressing MΦ was significantly reduced compared to control. These data suggest that CD206+ MΦ promotes the formation of endometriotic-like lesions by inducing angiogenesis around the lesions.


2021 ◽  
pp. 112972982110154
Author(s):  
Raffaella Mauro ◽  
Cristina Rocchi ◽  
Francesco Vasuri ◽  
Alessia Pini ◽  
Anna Laura Croci Chiocchini ◽  
...  

Background: Arteriovenous fistula (AVF) for hemodialysis integrates outward remodeling with vessel wall thickening in response to drastic hemodynamic changes. Aim of this study is to determine the role of Ki67, a well-established proliferative marker, related to AVF, and its relationship with time-dependent histological morphologic changes. Materials and methods: All patients were enrolled in 1 year and stratified in two groups: (A) pre-dialysis patients submitted to first AVF and (B) patients submitted to revision of AVF. Morphological changes: neo-angiogenesis (NAG), myointimal thickening (MIT), inflammatory infiltrate (IT), and aneurysmatic fistula degeneration (AD). The time of AVF creation was recorded. A biopsy of native vein in Group A and of arterialized vein in Group B was submitted to histological and immunohistochemical (IHC) analysis. IHC for Ki67 was automatically performed in all specimens. Ki67 immunoreactivity was assessed as the mean number of positive cells on several high-power fields, counted in the hot spots. Results: A total of 138 patients were enrolled, 69 (50.0%) Group A and 69 (50.0%) Group B. No NAG or MIT were found in Group A. Seven (10.1%) Group A veins showed a mild MIT. Analyzing the Group B, a moderate-to-severe MIT was present in 35 (50.7%), IT in 19 (27.5%), NAG in 37 (53.6%); AD was present in 10 (14.5%). All AVF of Group B with the exception of one (1.4%) showed a positivity for Ki67, with a mean of 12.31 ± 13.79 positive cells/hot spot (range 0–65). Ki67-immunoreactive cells had a subendothelial localization in 23 (33.3%) cases, a myointimal localization in SMC in 35 (50.7%) cases. The number of positive cells was significantly correlated with subendothelial localization of Ki67 ( p = 0.001) and with NA ( p = 0.001). Conclusions: Native veins do not contain cycling cells. In contrast, vascular cell proliferation starts immediately after AVF creation and persists independently of the time the fistula is set up. The amount of proliferating cells is significantly associated with MIT and subendothelial localization of Ki67-immunoreactive cells, thus suggesting a role of Ki-67 index in predicting AVF failure.


Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2876
Author(s):  
Giovanni Manfredi Assanto ◽  
Giulia Ciotti ◽  
Mattia Brescini ◽  
Maria Lucia De Luca ◽  
Giorgia Annechini ◽  
...  

Background: Despite that the unfavorable prognostic role of a high Total Metabolic Tumor Volume (TMTV) in Follicular Lymphoma has been demonstrated, the role of SUVmax alone at baseline PET/CT could have a different prognostic role. Patients and Methods: We performed a retrospective observational monocentric cohort study. All patients affected by FL who underwent a basal PET/CT were included. Two subgroups were identified and compared in terms of PFS and OS: (A) Basal SUVmax ≤ 6; and (B) Basal SUVmax > 6. Results: Ninety-four patients were included, 34 in group A (36.2%) and 60 in group B (63.8%). The PFS at two years was comparable in the two groups (97%). The five-year PFS was 73.5% for group A and 95% for group B (p 0.005). The five-year PFS in the whole cohort was 87.5%. A clear advantage was confirmed in group A in the absence of other risk factors. Patients with SUVmax ≤ 6 and no risk factors showed a 5-year PFS of 73% against 83% for patients with SUVmax > 6 and at least two risk factors. Conclusion: A high FDG uptake favorably correlated with PFS. A low basal SUVmax reflected a higher rate of late relapse requiring a prolonged follow-up. The basal SUVmax is an approachable parameter with prognostic implications.


Sign in / Sign up

Export Citation Format

Share Document