Chapter two begins by providing an overview of the prehistory and early history of the western Indian Ocean, setting the Comoros in the wider context. It then goes on to discuss various hypotheses regarding the first settlement of the islands, based on the archaeology of the islands, the nearby African coast and Madagascar. Genetic analysis and archaeological findings confirm the contributions of Arab, Austronesian and African settlers to the local population. The basic social structures of the islands’ people are discussed, matrilineality and the development of religious practices following the arrival of Islam, drawing on both oral traditions and archaeological evidence. It looks at how the islands were incorporated into wider trading systems and, with the arrival of Shirazis, a regional cultural complex.

From the Origins: Archaeology and Traditions

Insects have several different types of blood cell, many of which are unable to divide to form new cells once they have matured. Instead, fresh blood cells are normally generated in specialized ‘hematopoietic’ organs, such as the lymph gland in the Drosophila species of fruit fly. The structure of these organs plays an important role in controlling how new blood cells develop. Drosophila embryos make two types of blood cell: plasmatocytes and crystal cells. Both defend against harmful microorganisms, but in different ways. Plasmatocytes engulf and destroy invaders, whereas crystal cells release chemicals that encase microbes in a hardened gel. The blood cells made in the Drosophila embryo are still present once the fly enters its larval stages. At this stage of development, most of the blood cells are found in clusters attached to the cuticle that covers the larva's surface, but a few circulate freely around the larva's body. As a Drosophila larva develops, the number of blood cells in the larva increases. However, previous work has shown these additional blood cells are not normally released from the lymph gland of the larva. Furthermore, mature crystal cells do not appear to form new cells by dividing in two. Leitao and Sucena now show that the stationary clusters of blood cells produce new crystal cells in Drosophila larvae. Within the clusters, plasmatocytes are made to turn into crystal cells via a signaling pathway controlled by a protein called Notch. This pathway was already known to be essential for forming crystal cells. Leitao and Sucena also show that the structure of the clusters influences whether crystal cells are made, which means that the clusters can be considered to be hematopoietic tissue. It is now important to compare how the production of the same cell type is controlled in two distinct hematopoietic structures: the clusters and the lymph gland. From this comparison, general principles may be drawn and tested in other systems, including vertebrates.

https://arca.igc.gulbenkian.pt/bitstream/10400.7/414/1/Leitao_Elife2015.pdf

Drosophila sessile hemocyte clusters are true hematopoietic tissues that regulate larval blood cell differentiation

Insects and mammals share an ancient innate immune system comprising both humoral and cellular responses. The insect immune system consists of the fat body, which secretes effector molecules into the hemolymph and several classes of hemocytes, which reside in the hemolymph and of protective border epithelia. Key features of wound- and immune responses are shared between insect and mammalian immune systems including the mode of activation by commonly shared microbial (non-self) patterns and the recognition of these patterns by dedicated receptors. It is unclear how metazoan parasites in insects, which lack these shared motifs, are recognized. Research in recent years has demonstrated that during entry into the insect host, many eukaryotic pathogens leave traces that alert potential hosts of the damage they have aﬄicted. In accordance with terminology used in the mammalian immune systems, these signals have been dubbed danger- or damage-associated signals. Damage signals are necessary byproducts generated during entering hosts either by mechanical or proteolytic damage. Here, we briefly review the current stage of knowledge on how wound closure and wound healing during mechanical damage is regulated and how damage-related signals contribute to these processes. We also discuss how sensors of proteolytic activity induce insect innate immune responses. Strikingly damage-associated signals are also released from cells that have aberrant growth, including tumor cells. These signals may induce apoptosis in the damaged cells, the recruitment of immune cells to the aberrant tissue and even activate humoral responses. Thus, this ensures the removal of aberrant cells and compensatory proliferation to replace lost tissue. Several of these pathways may have been co-opted from wound healing and developmental processes.

/pdf/damage-signals-in-the-insect-immune-response-44dudou6v5.pdf

Damage signals in the insect immune response

Yeast studies identified two heterohexameric tethering complexes, which consist of 4 shared (Vps11, Vps16, Vps18 and Vps33) and 2 specific subunits: Vps3 and Vps8 (CORVET) versus Vps39 and Vps41 (HOPS). CORVET is an early and HOPS is a late endosomal tether. The function of HOPS is well known in animal cells, while CORVET is poorly characterized. Here we show that Drosophila Vps8 is highly expressed in hemocytes and nephrocytes, and localizes to early endosomes despite the lack of a clear Vps3 homolog. We find that Vps8 forms a complex and acts together with Vps16A, Dor/Vps18 and Car/Vps33A, and loss of any of these proteins leads to fragmentation of endosomes. Surprisingly, Vps11 deletion causes enlargement of endosomes, similar to loss of the HOPS-specific subunits Vps39 and Lt/Vps41. We thus identify a 4 subunit-containing miniCORVET complex as an unconventional early endosomal tether in Drosophila.

MiniCORVET is a Vps8-containing early endosomal tether in Drosophila.

Eater and NimC1 are transmembrane receptors of the Drosophila Nimrod family, specifically expressed in haemocytes, the insect blood cells. Previous ex vivo and in vivo RNAi studies have pointed to their role in the phagocytosis of bacteria. Here, we have created a novel NimC1 null mutant to re‐evaluate the role of NimC1, alone or in combination with Eater, in the cellular immune response. We show that NimC1 functions as an adhesion molecule ex vivo, but in contrast to Eater it is not required for haemocyte sessility in vivo. Ex vivo phagocytosis assays and electron microscopy experiments confirmed that Eater is the main phagocytic receptor for Gram‐positive, but not Gram‐negative bacteria, and contributes to microbe tethering to haemocytes. Surprisingly, NimC1 deletion did not impair phagocytosis of bacteria, nor their adhesion to the haemocytes. However, phagocytosis of both types of bacteria was almost abolished in NimC1 1 ;eater 1 haemocytes. This indicates that both receptors contribute synergistically to the phagocytosis of bacteria, but that Eater can bypass the requirement for NimC1. Finally, we uncovered that NimC1, but not Eater, is essential for uptake of latex beads and zymosan particles. We conclude that Eater and NimC1 are the two main receptors for phagocytosis of bacteria in Drosophila, and that each receptor likely plays distinct roles in microbial uptake.

Two Nimrod receptors, NimC1 and Eater, synergistically contribute to bacterial phagocytosis in Drosophila melanogaster.

Genes encoding cuticular proteins are components of the Nimrod gene cluster in Drosophila.

In recent years, Drosophila melanogaster has become an attractive model organism in which to study the structure and development of the cellular immune components. The emergence of immunological markers greatly accelerated the identification of the immune cells (hemocytes), while the creation of genetic reporter constructs allowed unique insight into the structural organization of hematopoietic tissues. However, investigation of the hemocyte compartments by the means of immunological markers requires dissection and fixation, which regularly disrupt the delicate structure and hamper the microanatomical characterization. Moreover, the investigation of transgenic reporters alone can be misleading as their expression often differs from the native expression pattern of their respective genes. We describe here a method that combines the reporter constructs and the immunological tools in live imaging, thereby allowing use of the array of available immunological markers while retaining the structural integrity of the hematopoietic compartments. The procedure allows the reversible immobilization of Drosophila larvae for high-resolution confocal imaging and the time-lapse video analysis of in vivo reporters. When combined with our antibody injection-based in situ immunostaining assay, the resulting double labeling of the hemocyte compartments can provide new information on the microanatomy and functional properties of the hematopoietic tissues in an intact state. Although this method was developed to study the immune system of Drosophila melanogaster, we anticipate that such a combination of genetic and immunological markers could become a versatile technique for in vivo studies in other biological systems too.

/pdf/in-vivo-immunostaining-of-hemocyte-compartments-in-42mpcyf4gt.pdf

In vivo immunostaining of hemocyte compartments in Drosophila for live imaging.

Nomadic groups of conquering Hungarians played a predominant role in Hungarian prehistory, but genetic data are available only from the immigrant elite strata. Most of the 10–11th century remains in the Carpathian Basin belong to common people, whose origin and relation to the immigrant elite have been widely debated. Mitogenome sequences were obtained from 202 individuals with next generation sequencing combined with hybridization capture. Median joining networks were used for phylogenetic analysis. The commoner population was compared to 87 ancient Eurasian populations with sequence-based (Fst) and haplogroup-based population genetic methods. The haplogroup composition of the commoner population markedly differs from that of the elite, and, in contrast to the elite, commoners cluster with European populations. Alongside this, detectable sub-haplogroup sharing indicates admixture between the elite and the commoners. The majority of the 10–11th century commoners most likely represent local populations of the Carpathian Basin, which admixed with the eastern immigrant groups (which included conquering Hungarians).

https://www.mdpi.com/2073-4425/12/3/460/pdf

Maternal Lineages from 10–11th Century Commoner Cemeteries of the Carpathian Basin

Due to the evolutionary conservation of the regulation of hematopoiesis, Drosophila provides an excellent model organism to study blood cell differentiation and hematopoietic stem cell (HSC) maintenance. The larvae of Drosophila melanogaster respond to immune induction with the production of special effector blood cells, the lamellocytes, which encapsulate and subsequently kill the invader. Lamellocytes differentiate as a result of a concerted action of all three hematopoietic compartments of the larva: the lymph gland, the circulating hemocytes, and the sessile tissue. Within the lymph gland, the communication of the functional zones, the maintenance of HSC fate, and the differentiation of effector blood cells are regulated by a complex network of signaling pathways. Applying gene conversion, mutational analysis, and a candidate based genetic interaction screen, we investigated the role of Headcase (Hdc), the homolog of the tumor suppressor HECA in the hematopoiesis of Drosophila. We found that naive loss-of-function hdc mutant larvae produce lamellocytes, showing that Hdc has a repressive role in effector blood cell differentiation. We demonstrate that hdc genetically interacts with the Hedgehog and the Decapentaplegic pathways in the hematopoietic niche of the lymph gland. By adding further details to the model of blood cell fate regulation in the lymph gland of the larva, our findings contribute to the better understanding of HSC maintenance.

https://www.mdpi.com/2073-4425/10/3/173/pdf

Headcase is a Repressor of Lamellocyte Fate in Drosophila melanogaster.

Középkori uralkodóink sírjai a történelem viharaiban elvesztek, maradványaik ismeretlen helyen, azonosítatlanul nyugszanak. Máig egyedül III. Béla maradványai kerültek elő, valamint szent királyaink ereklyéi maradtak meg az utókornak, melyek eredetiségét azonban sokan kétségbe vonják. Munkánk során a legtöbb királyunk temetkezési helyéül szolgált székesfehérvári királyi bazilika területén feltárt maradványok archeogenetikai vizsgálatát végezzük el, és azonosítjuk uralkodóink csontvázait. Emellett a Szent László-herma koponyaereklyéjét is megvizsgáltuk, hogy valódiságát igazoljuk. Míg a székesfehérvári vizsgálatokból csak részeredményeket közlünk, lévén a munka még nem fejeződött be, addig a herma vizsgálata lezajlott, bemutatjuk, hogy eredetisége igazolást nyert, valóban Szent László koponyáját rejti. Mi több, azt is ismertetjük, hogyan járult hozzá Szent László genomvizsgálata az Árpád-házi maradványok személyazonosításához, és kimutatjuk a honfoglalók genetikai örökségét a Szent Király örökítőanyagában. 

/pdf/kozepkori-magyar-uralkodok-archeogenetikai-vizsgalata-k5p4p0l7.pdf

Gergely I. B. Varga

Papers

Genes encoding cuticular proteins are components of the Nimrod gene cluster in Drosophila.

In vivo immunostaining of hemocyte compartments in Drosophila for live imaging.

Maternal Lineages from 10–11th Century Commoner Cemeteries of the Carpathian Basin

Headcase is a Repressor of Lamellocyte Fate in Drosophila melanogaster.

Középkori magyar uralkodók archeogenetikai vizsgálata