Host Control Research Articles

Культ огня в охотопромысловой деятельности и бытовой культуре тунгусо-маньчжурских этносов Нижнего Амура и Приморья

The article discusses the problem of ethnic mysteries connected with the worship of the fire cult of the Tungus-Manchurian ethnic groups of the Far East based on field published materials and literary sources. The relevance of the research goal is determined by the scientific and public interests of the small indigenous peoples of the Amur region, Primorye and other regions of Russia. This goal is achieved by a detailed study of numerous rituals, prohibitions and signs that are directly related to hunting and the everyday culture of the fishing population of the Tungus-Manchu ethnic groups. According to the worldview of the Nanai, Negidal, Orochi, the article was prepared taking into account ethnological research methods and ethnographic approaches such as visual observation and personal involvement in the mysteries associated with the rituals of worship, feeding the “god” of fire Pudza and the request of the hunters from the master of the taiga Onku a successful hunt. Ulchi, Udege and other Tungus-Manchurian ethnic groups of the southern part of the Russian Far East, it was believed that the fire master Pudza Ezani had the toad of Jala (guarding the fire from self-extinguishing), Ikte forest ants, who helped the toad, to maintain a “good” fire, as well as the Sugdugu bird - the kingfisher – the servant of the ant host Ikta Ezani, and the wild boar Aulа, who was the first in the taiga to report insane fire (fire) that escaped the host's control. All traditional life, hunting, fishing and gathering of the Tungus-Manchu ethnic groups of the Lower Amur and Primorye were associated with the worship and preservation of old rituals and traditions of the ancient ancestors, who laid the economic and cultural basis for the existence of their descendants.

Responses triggered in chloroplast of Chlorella variabilis NC64A by long-term association with Paramecium bursaria.

The unicellular green alga Chlorella variabilis NC64A is an endosymbiont of the ciliate Paramecium bursaria. The host's control, including the transfer of biochemical substrates from P. bursaria to C. variabilis, is involved in symbiotic relationships. C. variabilis NC64A that had been re-infected to P. bursaria for more than 1year and isolated from the host showed higher chlorophyll levels compared to those in free-living cells. Unlike the host, the expression of C. variabilis NC64A heat shock 70kDa protein was independent of establishment of endosymbiosis. In symbiotic cells, the levels of PII signal transduction protein (CvPII) that coordinate the central C/N anabolic metabolism were slightly higher than those in free-living cells. Furthermore, the environmental cues (light and host food bacteria availability) affected the abundance of CvPII, suggesting that synthesis of the protein was influenced by the host. Moreover, arginine concentrations in the symbiotic algae of P. bursaria were also controlled by the host's nutritional conditions. Together, our results imply that signal substrates and/or products of metabolism in host cells might act as messengers mediating the regulation of key events in symbiont cells.

NDynamic Framework for Secure VM Migration over Cloud Computing

In the centralized cloud controlled environment, the decision-making and monitoring play crucial role where in the host controller (HC) manages the resources across hosts in data center (DC). HC does virtual machine (VM) and physical hosts management. The VM management includes VM creation, monitoring, and migration. If HC down,the services hosted by various hosts in DC can`t be accessed outside the DC. Decentralized VM management avoids centralized failure by considering one of the hosts from DC as HC that helps in maintaining DC in running state. Each host in DC has many VM`s with the threshold limit beyond which it can`t provide service.To maintain threshold , the host`s in DC does VM migration across various hosts. The data in migration is in the form of plaintext, the intruder can analyze packet movement and can control hosts traffic. The incorporation of security mechanism on hosts in DC helps protecting data in migration. This paper discusses an approach for dynamic HC selection, VM selection and secure VM migration over cloud environment.

Insect’s intestinal organ for symbiont sorting

Symbiosis has significantly contributed to organismal adaptation and diversification. For establishment and maintenance of such host-symbiont associations, host organisms must have evolved mechanisms for selective incorporation, accommodation, and maintenance of their specific microbial partners. Here we report the discovery of a previously unrecognized type of animal organ for symbiont sorting. In the bean bug Riptortus pedestris, the posterior midgut is morphologically differentiated for harboring specific symbiotic bacteria of a beneficial nature. The sorting organ lies in the middle of the intestine as a constricted region, which partitions the midgut into an anterior nonsymbiotic region and a posterior symbiotic region. Oral administration of GFP-labeled Burkholderia symbionts to nymphal stinkbugs showed that the symbionts pass through the constricted region and colonize the posterior midgut. However, administration of food colorings revealed that food fluid enters neither the constricted region nor the posterior midgut, indicating selective symbiont passage at the constricted region and functional isolation of the posterior midgut for symbiosis. Coadministration of the GFP-labeled symbiont and red fluorescent protein-labeled Escherichia coli unveiled selective passage of the symbiont and blockage of E. coli at the constricted region, demonstrating the organ's ability to discriminate the specific bacterial symbiont from nonsymbiotic bacteria. Transposon mutagenesis and screening revealed that symbiont mutants in flagella-related genes fail to pass through the constricted region, highlighting that both host's control and symbiont's motility are involved in the sorting process. The blocking of food flow at the constricted region is conserved among diverse stinkbug groups, suggesting the evolutionary origin of the intestinal organ in their common ancestor.

Specific Midgut Region Controlling the Symbiont Population in an Insect-Microbe Gut Symbiotic Association

Many insects possess symbiotic bacteria that affect the biology of the host. The level of the symbiont population in the host is a pivotal factor that modulates the biological outcome of the symbiotic association. Hence, the symbiont population should be maintained at a proper level by the host's control mechanisms. Several mechanisms for controlling intracellular symbionts of insects have been reported, while mechanisms for controlling extracellular gut symbionts of insects are poorly understood. The bean bug Riptortus pedestris harbors a betaproteobacterial extracellular symbiont of the genus Burkholderia in the midgut symbiotic organ designated the M4 region. We found that the M4B region, which is directly connected to the M4 region, also harbors Burkholderia symbiont cells, but the symbionts therein are mostly dead. A series of experiments demonstrated that the M4B region exhibits antimicrobial activity, and the antimicrobial activity is specifically potent against the Burkholderia symbiont but not the cultured Burkholderia and other bacteria. The antimicrobial activity of the M4B region was detected in symbiotic host insects, reaching its highest point at the fifth instar, but not in aposymbiotic host insects, which suggests the possibility of symbiont-mediated induction of the antimicrobial activity. This antimicrobial activity was not associated with upregulation of antimicrobial peptides of the host. Based on these results, we propose that the M4B region is a specialized gut region of R. pedestris that plays a critical role in controlling the population of the Burkholderia gut symbiont. The molecular basis of the antimicrobial activity is of great interest and deserves future study.

Telomeres and viruses: common themes of genome maintenance

Genome maintenance mechanisms actively suppress genetic instability associated with cancer and aging. Some viruses provoke genetic instability by subverting the host’s control of genome maintenance. Viruses have their own specialized strategies for genome maintenance, which can mimic and modify host cell processes. Here, we review some of the common features of genome maintenance utilized by viruses and host chromosomes, with a particular focus on terminal repeat (TR) elements. The TRs of cellular chromosomes, better known as telomeres, have well-established roles in cellular chromosome stability. Cellular telomeres are themselves maintained by viral-like mechanisms, including self-propagation by reverse transcription, recombination, and retrotransposition. Viral TR elements, like cellular telomeres, are essential for viral genome stability and propagation. We review the structure and function of viral repeat elements and discuss how they may share telomere-like structures and genome protection functions. We consider how viral infections modulate telomere regulatory factors for viral repurposing and can alter normal host telomere structure and chromosome stability. Understanding the common strategies of viral and cellular genome maintenance may provide new insights into viral–host interactions and the mechanisms driving genetic instability in cancer.

Ubiquitylation and autophagy in the control of bacterial infections and related inflammatory responses

The ubiquitin proteasome system and autophagy constitute key signalling pathways in the host response to infection. The identification of adaptors linking the two pathways has prompted a re-examination of the latter's involvement in inflammatory reactions and the clearance of bacteria. The ubiquitin-autophagy pathway is a preferred target for effectors from pathogens that seek to exploit and evade the host defence mechanisms. A number of new players and signalling nodes have recently been identified. Here, we discuss these new insights into the host's control of bacterial infection.

Metabolic interactions between algal symbionts and invertebrate hosts

Some invertebrates have enlisted autotrophic unicellular algae to provide a competitive metabolic advantage in nutritionally demanding habitats. These symbioses exist primarily but not exclusively in shallow tropical oceanic waters where clear water and low nutrient levels provide maximal advantage to the association. Mostly, the endosymbiotic algae are localized in host cells surrounded by a host-derived membrane (symbiosome). This anatomy has required adaptation of the host biochemistry to allow transport of the normally excreted inorganic nutrients (CO2, NH3 and PO43-) to the alga. In return, the symbiont supplies photosynthetic products to the host to meet its energy demands. Most attention has focused on the metabolism of CO2 and nitrogen sources. Carbon-concentrating mechanisms are a feature of all algae, but the products exported to the host following photosynthetic CO2 fixation vary. Identification of the stimulus for release of algal photosynthate in hospite remains elusive. Nitrogen assimilation within the symbiosis is an essential element in the host's control over the alga. Recent studies have concentrated on cnidarians because of the impact of global climate change resulting in coral bleaching. The loss of the algal symbiont and its metabolic contribution to the host has the potential to result in the transition from a coral-dominated to an algal-dominated ecosystem.

This month in J Lab Clin Med: Issue highlights for October 2000

This month in J Lab Clin Med: Issue highlights for October 2000

The inhibition of lymphocyte stimulation by autologous human metastatic melanoma cells correlates with the expression of HLA-DR antigens on the tumor cells.

Previous studies indicated that peripheral blood lymphocytes from patients (Pt-PBL) with lymph node metastatic melanomas proliferated in vitro and developed into tumor-restricted cytotoxic lymphocytes in response to alloantigens or interleukin 2 (IL-2). However, Pt-PBL were not stimulated by irradiated autologous metastatic melanoma (Auto-Me) cells. In the present study we report that the lack of stimulatory activity of Auto-Me cells may be due to a suppressive effect exerted by Auto-Me cells on the responder lymphocytes. In fact, we found that in 62% of cases examined, the addition of 5-10% Auto-Me cells to Pt-PBL cultures strongly inhibited both proliferation and the generation of tumor cytotoxic lymphocytes induced by alloantigens or IL-2. The inhibition was dose-dependent and tumor-restricted, and was not due either to toxicity, medium depletion or IL-2 absorption by Auto-Me cells. Normal fibroblasts, K562 cells and autologous E-lymphocytes were not suppressive. Auto-Me cells were able to inhibit Pt-PBL responses only when added during the first 24 h of culture and not later. Phenotypic analysis of Auto-Me cells using monoclonal antibodies directed against HLA-A,B,C, HLA-DR and melanoma-associated antigens revealed that the expression of high levels of DR antigens on Auto-Me cells was associated with an elevated suppressive activity. Conversely, Auto-Me cells with low or undetectable levels of DR antigens were not inhibitory. Furthermore, the increased expression of DR antigens on Auto-Me cells obtained by in vitro treatment with human interferon gamma (IFN-gamma) also resulted in an increased suppressive activity. We conclude that HLA-DR+ metastatic melanoma cells can interfere with the generation of an anti-tumor immune response, thus potentially favoring the escape of the tumor from the host's control mechanism.

Role of NK cells in tumour growth and metastasis in beige mice.

Although natural killer (NK) cells are thought to give the host a spontaneous resistance against tumours and have been postulated to act in vivo as surveillor cells, definitive data in support of these hypotheses has not been obtained. Recently the beige (bg) mouse, a morphological homologue of the human Chediak-Higashi (CH) syndrome, was shown to be deficient in NK activity. Specifically, spleen cells of bg mice were demonstrated to be incapable of in vitro natural cytotoxicity against tumour cells. We report here that a tumour line, modified to be sensitive to NK cytotoxicity by in vitro culture, demonstrated in vivo an increased growth rate, faster induction time and an increased metastatic capability in bg compared to control mice. This was not found with a tumour line insensitive to NK activity (without in vitro culture). In vivo activation of NK cells in bg and control mice resulted in a decrease in tumour growth rate and metastatic frequency. These results demonstrate that NK cells have an important function in the host's control of tumour growth and metastasis.

CANCER BIOLOGY: VIRAL AND EPIGENETIC*

CANCER BIOLOGY: VIRAL AND EPIGENETIC*