Protective effect of Dunaliella salina (Volvocales, Chlorophyta) against experimentally induced fibrosarcoma on wistar rats

The beta-carotene-yielding microalga, Dunaliella salina (Dunal) Teod. maintained in De Walne's medium was harvested and lyophilized. Fibrosarcoma was induced in rats by 20-methylcholanthrene. 0.5 g and 1.0 g of lyophilized D. salina powder was administered to the rats orally through carboxy methyl cellulose. Cisplatin was administered along with vitamin E to compare the protective effect of D. salina against fibrosarcoma. Administration of D. salina decreased the levels of cholesterol and lactate dehydrogenase as well as the activities of catalase, superoxide dismutase, serum aspartate aminotransaminase, serum alanine aminotransferase, when compared to control. A significant reduction in the levels of hepatic and renal RNA and DNA was observed in the sarcoma rats when treated with D. salina powder. Histopathological studies of tumor tissues showed regenerative and regressive changes. beta-carotene globules isolated from the powder of Dunaliella salina confirmed the presence of 9-cis-beta-carotene and all-trans-beta-carotene.     

Decreased Frequencies of Circulating CD4+ T Follicular Helper Cells Associated with Diminished Plasma IL-21 in Active Pulmonary Tuberculosis

Background

Circulating T follicular helper (Tfh) cells represent a distinct subset of CD4⁺ T cells and are important in immunity to infections. Although they have been shown to play a role in experimental models of tuberculosis infection, their role in human tuberculosis remains unexplored.

Aims/Methodology

To determine the distribution of circulating Tfh cells in human TB, we measured the frequencies of Tfh cells ex vivo and following TB - antigen or polyclonal stimulation in pulmonary TB (PTB; n = 30) and latent TB (LTB; n = 20) individuals, using the markers CXCR5, PD-1 and ICOS.

Results

We found that both ex vivo and TB - antigen induced frequencies of Tfh cell subsets was significantly lower in PTB compared to LTB individuals. Similarly, antigen induced frequencies of Tfh cells expressing IL-21 was also significantly lower in PTB individuals and this was reflected in diminished circulating levels of IL-21 and IFNγ. This was not accompanied by diminished frequencies of activated or memory B cell subsets. Finally, the diminution in frequency of Tfh cells in PTB individuals was dependent on IL-10, CTLA-4 and PD-L1 in vitro.

Conclusions

Thus, PTB is characterized by adiminution in the frequency of Tfh cell subsets.     

Coincident Helminth Infection Modulates Systemic Inflammation and Immune Activation in Active Pulmonary Tuberculosis

Background

Helminth infections are known to modulate innate and adaptive immune responses in active and latent tuberculosis (TB). However, the role of helminth infections in modulating responses associated with inflammation and immune activation (reflecting disease activity and/or severity) in TB is not known.

Methodology

We measured markers of inflammation and immune activation in active pulmonary TB individuals (ATB) with co-incidental Strongyloides stercoralis (Ss) infection. These included systemic levels of acute phase proteins, matrix metalloproteinases and their endogenous inhibitors and immune activation markers. As a control, we measured the systemic levels of the same molecules in TB-uninfected individuals (NTB) with or without Ss infection.

Principal Findings

Our data confirm that ATB is associated with elevated levels of the various measured molecules when compared to those seen in NTB. Our data also reveal that co-incident Ss infection in ATB individuals is associated with significantly decreased circulating levels of acute phase proteins, matrix metalloproteinases, tissue inhibitors of matrix metalloproteinases as well as the systemic immune activation markers, sCD14 and sCD163. These changes are specific to ATB since they are absent in NTB individuals with Ss infection.

Conclusions

Our data therefore reveal a profound effect of Ss infection on the markers associated with TB disease activity and severity and indicate that co-incidental helminth infections might dampen the severity of TB disease.     

Dendritic cells from C57BL/6 mice undergo activation and induce Th1-effector cell responses against Campylobacter jejuni

Food-borne Campylobacter jejuni (Cj) is an important cause of enteritis. We showed that C57BL/6 and congenic interleukin (IL)-10(-/-) mice serve as models of Cj colonization and enteritis, respectively. Thus, C57BL/6 mice are resistant to Cj induced disease. Because dendritic cells (DCs) are central to regulating adaptive immune responses, we investigated the interaction of Cj with murine bone marrow-derived DCs (BM-DCs) to assess bacterial killing, DC activation, and the ability of Cj-infected BM-DCs to stimulate Campylobacter-specific T cell responses in vitro. BM-DCs challenged with Cj efficiently internalized and killed Cj 11168 and significantly upregulated surface MHC-II, CD40, CD80 and CD86 demonstrating a mature phenotype. Infected BM-DCs secreted significant amounts of tumor necrosis factor-alpha (TNF-alpha), IL-6 and IL-12p70. Formalin-killed Cj also induced maturation of BM-DCs with similar cytokine production but at a significantly lower magnitude than live bacteria. Maximal activation of murine BM-DCs required internalization of Cj; attachment alone was not sufficient to elicit significant responses. Also, various strains of Cj elicited different magnitudes of cytokine production from BM-DCs. Finally, in a coculture system, Cj-infected BM-DCs induced high level interferon-gamma (INF-gamma) production from CD4+T cells indicating Th1 polarization. Thus, DCs from resistant C57BL/6 mice initiate T cell responses against Cj.     

Individual optimization: Mechanisms shaping the optimal reaction norm

In general, optimal reaction norms in heterogeneous populations can be obtained only by iterative numerical procedures (McNamara, 1991; Kawecki and Stearns, 1993). We consider two particular, but biologically plausible and analytically tractable cases of individual optimization to gain insight into the mechanisms which shape the optimal reaction norm of fecundity in relation to an environmental variable or an individual trait. In the first case, we assume that the quality of the environment (e.g. food abundance) or the quality of the individual (e.g. body size) is fixed during its entire life; it may also be a heritable individual trait. In the second case, individual quality is assumed to change randomly such that the probability distribution of quality in the next year is the same for the parent and for her offspring. For these two cases, we obtain analytical expressions for the shape of the optimal reaction norm, which are heuristically interpretable in terms of underlying selective mechanisms. It is shown that better quality may reduce the optimal fecundity. This outcome is particularly likely if better quality increases a fecundity-independent factor of parental survival in a long-lived species with fixed quality. This revised version was published online in July 2006 with corrections to the Cover Date.     

Pulmonary vasospasm in rabbits infused with stroma free haemoglobin solution

Effect of infusion of stroma free haemoglobin solution into mice and rabbits was studied. Though no abnormalities were noted in mice, pulmonary vasospasm and hepatocytic necrosis were seen in all rabbits. In addition to reports that low adenosine deaminase levels in the solution could be a cause of vasoconstriction, it is proposed on the basis of present results that either denaturation of haemoglobin molecule itself or release of super oxide anion during oxygenation of haemoglobin, could cause cellular damage leading to toxicity.     

Biological pretreatment and bioconversion of agricultural wastes,using ligninolytic and cellulolytic fungal consortia

Agricultural wastes have attractive potential as alternate energy sources. However, a major bottleneck is to identify eco-friendly treatment methodologies to utilize them. The large diversity of unexplored, novel, and potential microorganisms hold great promise and require periodic isolation and characterization of microorganisms for bioprospection. In this study, approximately 100 fungal isolates were tested for their lignocellulolytic enzyme activities, based on plate assay, followed by quantification of enzyme activity. From this, M2E (Inonotus tropicalis) and 2a (Cerrena unicolor) showed good growth and proficient ligninolytic activity; isolates GK1 (Chaetomium globosum) and GK2 (Chaetomium brasiliense) exhibited exceptional cellulolytic activity on lignocellulosic substrates such as rice straw and sugarcane bagasse. Consortia of the potential ligninolytic and cellulolytic isolates were set up to determine their ability to biodegrade the lignocellulosic substrates such as rice straw and sugarcane bagasse. The efficiency of the consortia was determined on the basis of the increase in enzyme activity; it was also evident through scanning electron microscopy, x-ray diffraction analysis of the degraded substrates, and the sugar yield. Experiments were also carried out to compare the biological with the physical pretreatment methods. The consortium of ligninolytic and cellulolytic marine-derived fungi developed in this study prove to have the potential for application in the effective utilization of agricultural wastes.