A single lycaenid caterpillar gets an ant‐constructed shelter and uninterrupted ant attendance

Ant‐lycaenid associations range from mutualism to parasitism and the caterpillars of some species of lycaenids are reported to enter ant nests for shelter, diapause, or pupation. The present study aimed to examine the nature of the association between Euchrysops cnejus (Fabricius) (Lepidoptera: Lycaenidae) and Camponotus compressus (Fabricius) (Hymenoptera: Formicidae) worker ants on the extrafloral nectary‐bearing cowpea plant, Vigna unguiculata (L.) Walp. (Fabaceae). The abundance patterns of the ants and the lycaenid caterpillars together with the spatial patrolling patterns of the ants on the plants revealed that ant abundance increased with the occurrence of the lycaenid caterpillars and the ants preferred the lycaenids over the extrafloral nectar. Camponotus compressus worker ants constructed a shelter at the cowpea plant base after interaction with one or more lycaenid caterpillar(s) and tended the caterpillars and pupae till the emergence of the butterfly. The ant‐constructed shelters (ACSs) inhabited by the minor caste workers (13 ± 1.3 ants per ACS), were utilized by the caterpillars to undergo pupation. The ants confined their activities predominantly to tending the pod‐feeding caterpillars and the solitary pupa within each ACS. It appears that the behavior of the tending worker ants is modulated by the lycaenid vulnerable stages.     

Phytohormone Priming: Regulator for Heavy Metal Stress in Plants

Phytohormones act as chemical messengers and, under a complex regulation, allow plants to sustain biotic and abiotic stresses. Thus, phytohormones are known for their regulatory role in plant growth and development. Heavy metals (HMs) play an important role in metabolism and have roles in plant growth and development as micronutrients. However, at a level above threshold, these HMs act as contaminants and pose a worldwide environmental threat. Thus, finding eco-friendly and economical deliverables to tackle this problem is a priority. In addition to physicochemical methods, exogenous application of phytohormones, i.e., auxins, cytokinins, and gibberellins, can positively influence the regulation of the ascorbate–glutathione cycle, transpiration rate, cell division, and the activities of nitrogen metabolism and assimilation, which improve plant growth activity. Brassinosteroids, ethylene and salicylic acid have been reported to enhance the level of the anti-oxidant system, decrease levels of ROS, lipid peroxidation and improve photosynthesis in plants, when applied exogenously under a HM effect. There is a crosstalk between phytohormones which is activated upon exogenous application. Research suggests that plants are primed by phytohormones for stress tolerance. Chemical priming has provided good results in plant physiology and stress adaptation, and phytohormone priming is underway. We have reviewed promising phytohormones, which can potentially confer enhanced tolerance when used exogenously. Exogenous application of phytohormones may increase plant performance under HM stress and can be used for agro-ecological benefits under environmental conditions with high HMs level.

     

Identification of amastigote-specific antigens of Leishmania donovani using kala-azar patient sera

Antigenic characterization of the soluble fraction of axenic amastigotes of Leishmania donovani ( strain Dd8, causative agent of Indian kala-azar) and their comparison with promastigotes is reported. The axenic amastigotes were assessed for their immunological status employing anti-A2 monoclonal antibody which is extremely specific for L. donovani amastigotes. SDS-PAGE of 35[S] methionine labeled proteins of the two parasite stages exhibited few stage specific and some conserved antigens in both the stages. An increased synthesis of heat shock proteins was observed in axenic amastigotes. Western blot experiments employing sera of kala azar positive patients identified immunodominent antigens of 116,83,26 and 12 kDa in axenic amastigotes which were not present in promastigotes. These amastigote stage specific antigens may have immense potential in immunodiagnosis and prophylaxis of kala-azar.     

Moderate severity heart failure does not involve a downregulation of myocardial fatty acid oxidation

Recent human and animal studies have demonstrated that in severe end-stage heart failure (HF), the cardiac muscle switches to a more fetal metabolic phenotype, characterized by downregulation of free fatty acid (FFA) oxidation and an enhancement of glucose oxidation. The goal of this study was to examine myocardial substrate metabolism in a model of moderate coronary microembolization-induced HF. We hypothesized that during well-compensated HF, FFA oxidation would predominate as opposed to a more fetal metabolic phenotype of greater glucose oxidation. Cardiac substrate uptake and oxidation were measured in normal dogs (n = 8) and in dogs with microembolization-induced HF (n = 18, ejection fraction = 28%) by infusing three isotopic tracers ([9,10-(3)H]oleate, [U-(14)C]glucose, and [1-(13)C]lactate) in anesthetized open-chest animals. There were no differences in myocardial substrate metabolism between the two groups. The total activity of pyruvate dehydrogenase, the key enzyme regulating myocardial pyruvate oxidation (and hence glucose and lactate oxidation) was not affected by HF. We did not observe any difference in the activity of carnitine palmitoyl transferase I (CPT-I) and its sensitivity to inhibition by malonyl-CoA between groups; however, malonyl-CoA content was decreased by 22% with HF, suggesting less in vivo inhibition of CPT-I activity. The differences in malonyl-CoA content cannot be explained by changes in the Michaelis-Menten constant and maximal velocity for malonyl-CoA decarboxylase because neither were affected by HF. These results support the concept that there is no decrease in fatty acid oxidation during compensated HF and that the downregulation of fatty acid oxidation enzymes and the switch to carbohydrate oxidation observed in end-stage HF is only a late-stage phenomenon.     

Adaptive response and split-dose effect of radiation on the survival of mice

Although the importance of radiation-induced adaptive response has been recognized in human health, risk assessment and clinical application, the phenomenon has not been understood well in terms of survival of animals. To examine this aspect Swiss albino mice were irradiated with different doses (2–10 Gy) at 0015 Gy/s dose rate and observed on a regular basis for 30 days. Since almost 50% lethality was seen with 8 Gy, it was selected as the challenging dose for further studies. Irradiation of mice with conditioning doses (0.25 or 0.5 Gy) and subsequent exposure to 8 Gy caused significant increase in the survival of mice compared to irradiated control. The splitting of challenging dose did not influence the efficiency of conditioning doses (0.25 Gy and 0.5 Gy) to induce an adaptive response. However conditioning doses given in fractions (0.25 Gy + 0.25 Gy) or (0.5 Gy + 0.5 Gy) were able to modulate the response of challenging dose of 8 Gy. These results clearly showed the occurrence of adaptive response in terms of survival of animals. The conditioning dose given in small fractions seemed to be more effective. The findings have been discussed from a mechanistic point of view. The possible biological implications, potential medical benefits, uncertainties and controversies related to adaptive response have also been addressed     

Integrin-linked kinase is a positive mediator of L6 myoblast differentiation

Overexpression of ILK in L6 myoblasts results in increased ILK kinase activity, stimulating myotube formation and induction of biochemical differentiation markers. Expression of a dominant negative ILK mutant, ILK(E359K), inhibits endogenous ILK activation and L6 differentiation. Cell cycle analysis of ILK(E359K) cells cultured in serum-free conditions indicates significant apoptosis (11-19% sub-diploid peak) which is not seen in insulin treated cells. Expression of ILK variants does not have significant effects on S-phase transit, however. Known targets of ILK, PKB/Akt or glycogen synthase kinase 3beta are not obviously involved in ILK-induced L6 differentiation. Insulin-stimulated phosphorylation of PKB at Ser473 is unimpaired in the ILK(E359K) cells, suggesting that PKB is not a myogenic target of ILK. Inhibition of GSK3beta by LiCl blocks L6 myogenesis, indicating that ILK-mediated inhibition of GSK3beta is not sufficient for differentiation. Our data do suggest that a LiCl-sensitive interaction of ILK is important in L6 myoblast differentiation.     

A data-mining approach to spacer oligonucleotide typing of Mycobacterium tuberculosis

MOTIVATION: The Direct Repeat (DR) locus of Mycobacterium tuberculosis is a suitable model to study (i) molecular epidemiology and (ii) the evolutionary genetics of tuberculosis. This is achieved by a DNA analysis technique (genotyping), called sp acer oligo nucleotide typing (spoligotyping ). In this paper, we investigated data analysis methods to discover intelligible knowledge rules from spoligotyping, that has not yet been applied on such representation. This processing was achieved by applying the C4.5 induction algorithm and knowledge rules were produced. Finally, a Prototype Selection (PS) procedure was applied to eliminate noisy data. This both simplified decision rules, as well as the number of spacers to be tested to solve classification tasks. In the second part of this paper, the contribution of 25 new additional spacers and the knowledge rules inferred were studied from a machine learning point of view. From a statistical point of view, the correlations between spacers were analyzed and suggested that both negative and positive ones may be related to potential structural constraints within the DR locus that may shape its evolution directly or indirectly. RESULTS: By generating knowledge rules induced from decision trees, it was shown that not only the expert knowledge may be modeled but also improved and simplified to solve automatic classification tasks on unknown patterns. A practical consequence of this study may be a simplification of the spoligotyping technique, resulting in a reduction of the experimental constraints and an increase in the number of samples processed.     

A spectrophotometric method to monitor the catalytic activity of microsomal cytochrome P-450 IIB1/2: comparison with fluorometric assay

A simple spectrophotometric method to monitor the catalytic activity of microsomal cytochrome P-450 IIB1/2 has been developed. The method employs measurement of utilization of NADPH, consumption of the substrate, pentoxyresorufin (PRF) and formation of the product, resorufin (RF) in the same reaction mixture containing hepatic microsomes from phenobarbital treated rats. The velocity of NADPH utilization (16.36 nmole/min/nmole P-450), PRF consumption (1.58 nmole/min/nmole P-450) and RF formation (1.57 nmole/min/nmole P-450) suggested a stoichiometry of 1:1 between the substrate and the product alongwith utilization of 10 molecules of NADPH. However, the Km for the enzyme activity (nmole RF formed/min/nmole P-450) using varying concentrations of PRF and NADPH as substrates were found to be 11.6 and 20.2 microM, respectively. The spectrophotometric method was compared with fluorometric method in terms of linearity with time, P-450 content and Vmax, Km values observed for the reaction. Inhibition studies with metyrapone and SKF 525A in the utilization of NADPH, consumption of PRF and formation of RF suggested that the method could be useful in monitoring the effect of various inhibitors on the P-450 IIB1/2 reaction.     

Antifertility,antibacterial, antifungal and percent disease incidence aspects of macrocyclic complexes of manganese(II)

Macrocyclic complexes of Mn(II) were synthesized by template condensation using 2,6-diaminopyridine and diethylenetriamine with malonic, succinic, glutaric and adipic acids. The reaction proceeded smoothly to completion. These 16- to 24-membered N(6), but behaving as tetradentate, macrocyclic complexes were characterized by elemental analyses, molecular weight determinations, infrared, electronic, mass and X-ray spectral analyses. The elemental analyses are consistent with the formation of complexes [Mn(N(6)L(n))Cl(2)]. All the complexes are stable and monomeric in nature, as indicated by the molecular weight determinations. The spectral studies confirmed the proposed framework of the new macrocyclic complexes and indicated an octahedral geometry around the central metal atom. The complexes were screened in vitro against a number of pathogenic fungi and bacteria to assess their growth-inhibiting potential. The testicular sperm density, sperm morphology, sperm motility, density of cauda epididymis, spermatozoa and fertility in mating trials and the biochemical parameters of the reproductive organs of the rat were examined and are discussed.     

A First Insight on the Population Structure of Mycobacterium tuberculosis Complex as Studied by Spoligotyping and MIRU-VNTRs in Santiago,Chile

Tuberculosis (TB) remains a significant public health problem worldwide, but the ecology of the prevalent mycobacterial strains, and their transmission, can vary depending on country and region. Chile is a country with low incidence of TB, that has a geographically isolated location in relation to the rest of South American countries due to the Andes Mountains, but recent migration from neighboring countries has changed this situation. We aimed to assess the genotypic diversity of Mycobacterium tuberculosis complex (MTBC) strains in Santiago, Chile, and compare with reports from other Latin-American countries. We analyzed MTBC isolates from pulmonary tuberculosis cases collected between years 2008 and 2013 in Central Santiago, using two genotyping methods: spoligotyping and 12-loci mycobacterial interspersed repetitive unit-variable number of tandem repeats (MIRU-VNTRs). Data obtained were analyzed and compared to the SITVIT2 database. Mean age of the patients was 47.5 years and 61% were male; 11.6% were migrants. Of 103 strains (1 isolate/patient) included, there were 56 distinct spoligotype patterns. Of these, 16 strains (15.5%) corresponded to orphan strains in the SITVIT2 database, not previously reported. Latin American and Mediterranean (LAM) (34%) and T (33%) lineages were the most prevalent strains, followed by Haarlem lineage (16.5%). Beijing family was scarcely represented with only two cases (1.9%), one of them isolated from a Peruvian migrant. The most frequent clustered spoligotypes were SIT33/LAM3 (10.7%), SIT53/T1 (8.7%), SIT50/H3 (7.8%), and SIT37/T3 (6.8%). We conclude that LAM and T genotypes are the most prevalent genotypes of MTBC in Santiago, Chile, and together correspond to almost two thirds of analyzed strains, which is similar to strain distribution reported from other countries of Latin America. Nevertheless, the high proportion of SIT37/T3, which was rarely found in other Latin American countries, may underline a specific history or demographics of Chile related to probable human migrations and evolutions.