Discriminant analysis as a tool to identify catfish (Ariidae) species of the excavated archaeological otoliths

Catfish otoliths excavated from two archaeological sites in Kuwait, Sabiyah (ca. 7000 Years Before Present) and Al-Khidr, ca. 4000 YBP, were compared with those of Kuwait’s modern catfish. Otoliths from Kuwait’s four species of catfish, Netuma bilineata, N. thalassina, Plicofollis dussumieri, and P. tenuispinis were collected after recording total length and weight. Data recorded for both ancient and modern otoliths, including annual ring (age), weight, length and four otolith radii from transverse sections, were subject to discriminant analysis to differentiate among species and develop classification functions for otoliths. Comparisons of the results from the ancient and modern otoliths showed that most of the excavated otoliths (78% from Sabiyah and 100% from Al-Khidr) belong to the two presently dominate species N. bilineata and P. tenuispinis, indicating that ichthyofauna of Kuwait Bay may not have changed much in the past 7000 years.     

Sulfur Isotope Fractionation and Kinetic Studies of Sulfite Reduction in Growing Cells of Salmonella heidelberg

A pulsed feeding technique was used during studies of sulfite reduction by Salmonella heidelberg in order to realize large percentages of SO₃⁼ conversion while simultaneously maintaining a reasonably stable cell population. As a consequence, much data for conventional kinetic and sulfur isotope fractionation computations were obtained in any one experiment. Under the conditions of supplying 150 μg glucose per ml of medium every 6 hr, anaerobiosis, and varying the SO₃⁼ concentration, the following observations were made: 1. Below 0.01% w/v Na₂SO₃, the reduction strictly followed first order kinetics with respect to SO₃⁼ concentration. At higher concentrations, the rate of SO₃⁼ reduction fell below that predicted by first order kinetics suggesting that a saturation effect was occurring. 2. At lower concentrations, the ratio of the isotopic rate constants k₁/k₂ was 1.02 whereas at higher SO₃⁼ levels, k₁/k₂ values of 1.04 were found. These latter effects are much higher than those obtained in the equivalent chemical reduction. On the basis of these observations, a model is considered which features two isotopically dependent steps and an intermediate reservoir which forms at higher SO₃⁼ concentrations. Results of an experiment under aerobic conditions and an experiment wherein the reduction rate was thermally altered, are also presented.     

Protective effect of 6-MFA, an interferon inducer against acrylamide neurotoxicity

Protective effect of 6-MFA, an interferon inducer and antiviral agent of fungal origin, was investigated against the neurotoxic effects induced by acrylamide in rats. Animals of 6-MFA (2.5, 5, 10 mg/100 gm, i.p.) pretreated plus acrylamide (ACR) group exhibited a reduction in development of hind limb paralysis which was 34, 25 and 20 (%) with increasing doses of 6-MFA respectively. Corpus striatal dopamine binding was significantly raised in the ACR treated rats while 6-MFA (10 mg) plus ACR group showed no significant change, in comparison to respective controls. Increased binding in the 6-MFA (2.5, 5 mg) pretreated plus ACR group was also evident. Glutathione-s-transferase (GST) activity was markedly reduced (66%) in ACR alone rats while no change was noted in rats pretreated with either dose of 6-MFA alone. However, a significant reversal was noted in animals of 6-MFA plus ACR group in a dose related manner. Conservation of glutathione levels and involvement of microglia, gamma-interferon and other lymphokines has been suggested for the observed protective effect of 6-MFA against neurotoxicity of ACR.     

Bilateral detection thresholds in dextrals and sinistrals reflect the more sensitive side of the nose, which is not lateralized [published erratum appears in Chem Senses 1998 Dec;23(6):761]

Several fundamental questions remain enigmatic concerning human olfactory sensitivity, including (i) whether detection threshold differences exist between the two sides of the nose (and, if so, whether such differences are influenced by handedness) and (ii) whether bilateral (i.e. binasal) stimulation leads to lower thresholds than unilateral stimulation (and, if so, whether the degree of facilitation is inversely related to general olfactory ability). In this study, and well-validated single staircase procedure was used to establish bilateral and unilateral detection thresholds for the cranial nerve I stimulant phenyl ethyl alcohol in 130 right- and 33 left-handed subjects. No differences in sensitivity between the left and right sides of the nose were observed in either group. Bilateral thresholds were lower, on average, than unilateral thresholds when the latter were categorized in terms of left and right nares. However, the bilateral thresholds did not differ significantly from those of the side of the nose with the lower threshold. Overall smell ability, as measured by the University of Pennsylvania Smell Identification Test, did not interact with any of the test measures. These data imply that (i) the left and right sides of the nose do not systematically differ in detection threshold sensitivity for either dextrals or sinistrals and (ii) if central integration of left:right olfactory threshold sensitivity occurs, its effects do not exceed the function of the better side of the nose.      

Retrotransposon based genetic status of North-West Himalayan Zingiber officinale revealed high heterogeneity

Inter-retrotransposon amplified polymorphism (IRAP) and retrotransposon-microsatellite amplified polymorphism (REMAP) techniques were successfully applied, for the first time, to analyze genetic diversity among 92 ginger landraces collected from north-western Himalayan region of India. Six IRAP primer/combinations generated 75 loci with an average of 12 loci/primer displaying an overall polymorphism of 95.95 %. On the other hand, twenty five REMAP primer combinations produced 414 loci with 96.5 % polymorphism. IRAP showed maximum Rp (5.39) and PIC (0.28) values, while the same in REMAP was observed to be 10.92 and 0.34. Cluster analysis using Jaccard’s similarity coefficient for IRAP and REMAP data ranged between 0.21 to 1.0 and 0.21 to 0.85, respectively distinguishing all the genotypes with diverse genetic makup. The results also confirmed the presence of sukkula retrotransposon (RT6) in the ginger genome which effectively acted as genetic marker revealing high regional genetic diversity in the ginger gene pool. The study will help in giving insight to the genetic constitution of vegetatively grown ginger crop and for its further utilization in improvement, conservation and management programmes.     

Specific inhibition of DNA polymerase beta by its 14 kDa domain: role of single- and double-stranded DNA binding and 5'-phosphate recognition.

DNA polymerase beta (beta-polymerase) has been implicated in short-patch DNA synthesis in the DNA repair pathway known as base excision repair. The native 39 kDa enzyme is organized into four structurally and functionally distinct domains. In an effort to examine this enzyme as a potential therapeutic target, we analyzed the effect of various beta-polymerase domains on the activity of the enzyme in vitro. We show that the 14 kDa N-terminal segment of beta-polymerase, which binds to both single- and double-stranded DNA, but lacks DNA polymerase activity, inhibits beta-polymerase activity in vitro. Most importantly, the 8, 27 and 31 kDa domains of beta-polymerase do not inhibit beta-polymerase activity, demonstrating that the inhibition by the 14 kDa domain is specific. The inhibition of beta-polymerase activity in vitro is abolished by increasing the concentrations of both of the substrates (template-primer and deoxynucleoside triphosphate). In contrast, an in vitro base excision repair assay is inhibited in a domain specific manner by the 14 kDa domain even in the presence of saturating substrates. The inhibition of beta-polymerase activity by the 14 kDa domain appears specific to beta-polymerase as this domain does not inhibit either mammalian DNA polymerase alpha or Escherichia coli polymerase I (Klenow fragment). These data suggest that the 14 kDa domain could be used as a potential inhibitor of intracellular beta-polymerase and that it may provide a means for sensitizing cells to therapeutically relevant DNA damaging agents.     

Thermal stress and physiological strain of children exposed to hot environments in a glass bangle factory

A group of 19 male children (mean age 12.1 years SEM 1.6 years) occupationally exposed to an excessively hot environment for an average duration of 2.5 years SEM 1.7 years in the glass bangle factory in Firozabad, India, were studied to evaluate the physiological strain induced by the thermal radiation (mean radiant temperature 46.2 degrees SEM 5.1 degrees C) and high ambient temperature (38.2 degrees SEM 3.4 degrees C) prevailing in the factory. Over a work-shift the mean increase in oral temperature was 0.90 degrees C in the exposed children, in comparison with the 0.40 degrees C increase recorded in the control children (p less than 0.05). The maximum increase in oral temperature was recorded in 'gulliwalas' (0.90 degrees C) and the minimum in 'battiwalas' (0.80 degrees C). The mean peak value of oral temperature (37.5 degrees C) was observed at 1600 hours. A significant increase in the pulse rate (25.9 beats.min-1) during the work-shift was observed in the exposed children in comparison with a mean increase of 9.4 beats.min-1 in the control group. Ventilatory studies showed pulmonary hyperventilation in the exposed workers. The increase in pulmonary ventilation was in the form of an increase in tidal volume and respiratory frequency induced by high environmental temperatures and thermal radiation. The cardio-respiratory responses showed physiological strain induced by the high ambient temperature and radiant heat prevailing in the glass bangle factory.