Song pattern recognition in the grasshopper Chorthippus biguttulus: the mechanism of syllable onset and offset detection

The male song of the duetting grasshopper Chorthippus biguttulus consists of syllables alternating with noisy pauses. The syllable-pause structure is important for song recognition by the female. Using playback experiments we investigated the mechanism by which intensity modulations within the song pattern are used to detect syllable onsets and offsets. We varied the relative onset level (level of the syllable beginning relative to the noisy pause) and the relative offset level (level of the noisy pause relative to the syllable end) independently in different experiments. For all females, an increase in intensity defining the syllable onset was necessary to evoke responses. Syllable offset cues were not always necessary: some females responded to continuous noise stimuli wherein only syllable onsets were marked by short pulses of high intensity. Those females that did not require syllable offset cues did not, however, lack a functional pause detection mechanism, since their responses to model songs containing silent pauses were restricted to a given range of pause durations. We propose that syllable-pause detection involves two independent processes: (1) syllable onset detection by a phasic neuronal unit that can be re-activated only after a short pause, and (2) the rejection of unacceptably long pauses by a second unit.     

Microbiologically influenced corrosion in petroleum product pipelines--a review

Microbiologically influenced corrosion is responsible for most of the internal corrosion problems in oil transportation pipelines and storage tanks. One problematic area in treating gas lines is the occurrence of the stratification of water in the line. Under these conditions, corrosion inhibitors do not come into contact properly and oil and inhibitors undergo degradation. The role of bacteria on oil degradation, the consequences of oil degradation in fuel systems and its influence on corrosion have been explained in detail. Besides, factors influencing on degradation of oil and corrosion inhibitors have also been discussed. Mechanism of microbiologically influenced corrosion in oil pipeline has been explained. Many of the misapplication of biocides/inhibitors occur mainly because the characteristics of biocides/inhibitors are not considered before use in pipeline industry. List of biocides and monitoring programme have been collected from literature and presented.     

Growth and nutritional status of the Bharia--a primitive tribe of Madhya Pradesh

This study is an attempt to understand the physical growth and nutritional status of Bharia, a primitive tribe of Central India. A cross sectional study was conducted on 551 children (283 boys and 268 girls) aged 4 to 18 years. Body weight, height, sitting height, head circumference, upper arm circumference, chest circumference, biceps, triceps, sub scapular and calf skin fold thickness were measured. Body Mass Index was calculated as weight/height2 to calculate chronic energy deficiency. All anthropometric measurements except skin fold measurement exhibit uniform increase with age in both the sexes. Age-specific Body Mass Index (BMI) indicated substantial changes and falls during pre-school age and rise in adolescence. The BMI according to the Indian standard was normal, but when the data was compared with the International standard malnutrition in both sexes was noticed in childhood. Boys remained undernourished after adolescence, while girls reached the normal growth patterns.     

ACTION OF PURINE AND PYRIMIDINE ANALOGS ON THE GROWTH AND DIFFERENTIATION OF THE GAMETOPHYTES OF THE FERN ASPLENIUM NIDUS

The purine analogs, 8-azaadenine, 8-azaguanine, 8-azaxanthine and 8-azahypoxanthine, and the pyrimidine analogs, 2-thiocytosine, 5-fluorouracil, 2-thiouracil and 6-azauracil, inhibited the induction of 2-dimensional growth in the gametophytes of the fern Asplenium nidus L. In contrast, thymine analogs such as 5-fluorodeoxyuridine, 2-thiothymine, 6-azathymine and 5-bromouracil caused non-specific growth inhibitions without suppressing 2-dimensional growth. Subinhibitory concentrations of 8-azaxanthine, 8-azahypoxanthine, and 2-thiouracil promoted both 1-dimensional and 2-dimensional phases of growth of the gametophytes. Inhibitory effects of the analogs were observed on treatment of the spores or of gametophytes of different ages. Gametophytes growing in the analogs for different periods of time recovered from inhibition on transfer to the basal medium.     

Chloroplast activities of dark-imbibed and photoinduced spores of the fernOnoclea sensibilis

Summary Chloroplast activities of dark-imbibed (non-germinating) and photoinduced (germinating) spores of the sensitive fern,Onoclea sensibilis were compared to gain insight into the germination process. There were no changes in the number of chloroplasts or in the chlorophyll contents of the spore during dark-imbibition and during the early phase of germination. Levels of increase in the Chloroplast DNA content of dark-imbibed and photoinduced spores were nearly the same and were associated with autoradiographic incorporation of [³H]thymidine into the cytoplasm. However, incorporation of the label into the nucleus occurred only during photoinduction of spores. Analysis of Chloroplast and nuclear DNA contents by dot-blot hybridization with labeled gene-specific probes has confirmed that chloroplast DNA content of the spore increases during dark-imbibition and photoinduction, while increase in nuclear DNA occurs only in photoinduced spores. Chloroplasts isolated from dark-imbibed and photoinduced spores incorporated [³H]TTP into an acid-insoluble fraction identified as DNA. The results show that physiological activities of chloroplasts of dark-imbibed and photoinduced spores ofO. sensibilis are similar and support an exclusive role for nuclear DNA synthesis in spore germination.     

In-vitro cytotoxicity and cell cycle analysis of two novel bis-1,2, 4-triazole derivatives: 1,4-bis[5-(5-mercapto-1,3,4-oxadiazol-2-yl-methyl)-thio-4-(p-tolyl)-1,2,4-triazol-3-yl]-butane (MNP-14) and 1,4-bis[5-(carbethoxy-methyl)-thio-4-(p-ethoxy phenyl)-1,2,4-triazol-3-yl]-butane (MNP-16)

In the present study, we have tested the cytotoxic and DNA damage activity of two novel bis-1,2,4 triazole derivatives, namely 1,4-bis[5-(5-mercapto-1,3,4-oxadiazol-2-yl-methyl)-thio-4-(p-tolyl)-1,2,4-triazol-3-yl]-butane (MNP-14) and 1,4-bis[5-(carbethoxy-methyl)-thio-4-(p-ethoxy phenyl) -1,2,4-triazol-3-yl]-butane (MNP-16). The effect of these molecules on cellular apoptosis was also determined. The in-vitro cytotoxicity was evaluated by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay as well as Trypan blue dye exclusion methods against human acute lymphoblastic leukemia (MOLT4) and lung cancer cells (A549). Our results showed that MNP-16 induced significant cytotoxicity (IC(50) of 3-5 μM) compared with MNP-14. The cytotoxicity induced by MNP-16 was time and concentration dependent. The cell cycle analysis by flow cytometry (fluorescence-activated cell sorting [FACS]) revealed that though there was a significant increase in the apoptotic population (sub-G(1) phase) with an increased concentration of MNP-14 and 16, there was no cell cycle arrest. Further, the comet assay results indicated considerable DNA strand breaks upon exposure to these compounds, thereby suggesting the possible mechanism of cytotoxicity induced by MNP-16. Hence, we have identified a novel molecule (MNP-16) which could be of great clinical relevance in cancer therapeutics.     

STUDIES ON THE GERMINATION OF SEEDS OF THE ROOT PARASITES,ALECTRA VOGELII AND STRIGA GESNERIOIDES. II. DNA SYNTHESIS AND DEVELOPMENT OF THE QUIESCENT CENTER IN THE RADICLE

DNA synthetic activity in the radicle meristem of embryos of germinating seeds of the obligate root parasites, Alectra vogelii and Striga gesnerioides was followed by autoradiography of ³H-thymidine incorporation. Incorporation of ³H-thymidine occurred in the nuclei of cells destined to form the vascular tissues, ground meristem and epidermis. An analysis of the distribution of labeled nuclei demonstrated the presence of a quiescent center of 2-4 cells in the radicle at the beginning of seed germination, becoming more prominent at later stages of germination. During continued growth of the radicle which resulted in a reduction in size of the meristem, cells of the original quiescent center were activated to undergo DNA synthesis.