Polycarpaea majumdariana (Caryophyllaceae)—a new species from Tamil Nadu, India

Polycarpaea majumdariana , a new species allied to P. aurea (Wight) Dunn from the Tamil Nadu plains, is described and illustrated.     

Protective effect of ellagic acid (EA) on micronucleus formation induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in mammalian cells, in in vitro assays and in vivo

The beneficial effects of fruits and vegetables with respect to age-related diseases such as diabetes, atherosclerosis and several types of cancer are widely recognized and confirmed by several epidemiological studies. A possible approach for evaluating the protective potential of promising diet constituents is to evaluate their beneficial effect with respect to a set of biomarkers that are indicative of a potential risk for developing degenerative diseases. Among the numerous biomarkers of the effect of food-related carcinogens and for the assessment of the degree of risk for disease, chromosomal damage detection is very predictive. The aim of this study was to test antigenotoxic effect of ellagic acid (EA) both in in vitro and in vivo studies, in combination with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a methylating agent. EA, a naturally occurring and widely distributed plant phenol, has been intensively studied but with conflicting results, depending on the endpoints considered and the experimental material employed. In vitro and in vivo studies differ in their experimental schedule: in the in vitro study pre- and post-treatments and simultaneous treatments with EA were performed, while in the in vivo study only pre-treatment was carried out. The results of this study clearly demonstrate a protective action of EA with respect to MNNG-induced micronuclei and cell proliferation both in vitro and in vivo. The lack of effect in the post-treatment in in vitro experiments excludes a possible effect of EA on DNA-repair systems. On the other hand, consumption of EA can have a protective action against primary DNA damage induced by oxidative stress.     

Morphological indicators of salinity stress and their relation with osmolyte associated redox regulation in mango cultivars

Soil salinization is a global issue impeding horticulture production and is approaching an alarming status due to climate change and urbanization. Breeding salt-tolerant rootstock varieties is an ideal strategy to mitigate stress due to salinity in mango and other perennial fruit species. Stress combating strategies employed by seedlings of 7 mango were studied under saline conditions (200 mM NaCl, EC: > 4.0 dSm⁻¹, pH 8.5) in pot experiments. Significantly high accumulation of proline (19.07 µg g⁻¹ FW in Bappakai), glycine betaine (55.11 µg g⁻¹ FW in 13–1), and total sugars (17.33 mg g⁻¹ FW in Kurukkan) were found to be the common mechanism employed by the tolerant cultivars to counter the osmotic stress, under suboptimal conditions. Non-enzymatic antioxidants viz., tannins (17.18 mg g⁻¹), phenols (18.68 mg g⁻¹), and anthocyanins (1.59 mg g⁻¹) were increased in seedling of "13–1", the salt-resistant cultivar from Israel. Reactive oxygen species (ROS) regulation by increased activity of superoxide dismutase and catalase in the two polyembryonic cultivars of Indian origin (Kurukkan and Nekkare) suggests their potential use as rootstocks to combat oxidative stress. The tolerance index of various cultivars was calculated by averaging the scores of morphological stress indicators, and its correlation with studied parameters suggests that salinity resilience is more tightly linked to enhanced catalase accumulation (r² = 0.8361) that is reduced ionic stress. This evidence assign the role of osmotic stress alleviation and redox regulation in salt tolerance mechanism operational in native Indian cultivars, Nekkare and Kurukkan at par with known salt tolerant rootstocks.

     

Gut Microbiota and Tacrolimus Dosing in Kidney Transplantation

Tacrolimus dosing to establish therapeutic levels in recipients of organ transplants is a challenging task because of much interpatient and intrapatient variability in drug absorption, metabolism, and disposition. In view of the reported impact of gut microbial species on drug metabolism, we investigated the relationship between the gut microbiota and tacrolimus dosing requirements in this pilot study of adult kidney transplant recipients. Serial fecal specimens were collected during the first month of transplantation from 19 kidney transplant recipients who either required a 50% increase from initial tacrolimus dosing during the first month of transplantation (Dose Escalation Group, n=5) or did not require such an increase (Dose Stable Group, n=14). We characterized bacterial composition in the fecal specimens by deep sequencing of the PCR amplified 16S rRNA V4-V5 region and we investigated the hypothesis that gut microbial composition is associated with tacrolimus dosing requirements. Initial tacrolimus dosing was similar in the Dose Escalation Group and in the Stable Group (4.2±1.1 mg/day vs. 3.8±0.8 mg/day, respectively, P=0.61, two-way between-group ANOVA using contrasts) but became higher in the Dose Escalation Group than in the Dose Stable Group by the end of the first transplantation month (9.6±2.4 mg/day vs. 3.3±1.5 mg/day, respectively, P<0.001). Our systematic characterization of the gut microbial composition identified that fecal Faecalibacterium prausnitzii abundance in the first week of transplantation was 11.8% in the Dose Escalation Group and 0.8% in the Dose Stable Group (P=0.002, Wilcoxon Rank Sum test, P<0.05 after Benjamini-Hochberg correction for multiple hypotheses). Fecal Faecalibacterium prausnitzii abundance in the first week of transplantation was positively correlated with future tacrolimus dosing at 1 month (R=0.57, P=0.01) and had a coefficient±standard error of 1.0±0.6 (P=0.08) after multivariable linear regression. Our novel observations may help further explain inter-individual differences in tacrolimus dosing to achieve therapeutic levels.     

Scaling theory of polymer translocation into confined regions

We examine the voltage-driven polymer translocation from a spacious region into a confined region imposed by two parallel planes, so that the entry is impeded by the entropic confinement but aided by the electric field inside the confined region. Two modes of entry are examined: linear translocation where a chain enters the confined region with chain ends, and hairpin translocation where a chain enters the confined region by forming a hairpin. Our calculation shows that translocation time increases with polymer length for linear entries but decreases with polymer length for hairpin entries. Applying to electrophoresis of DNA molecules through periodic spacious and confined regions, our theory shows that the dominance of hairpin translocations leads to the experimentally observed faster migration of longer DNA molecules. Our theory predicts experimental conditions for the validity of this law in terms of polymer length, size of the confined region, and solution conditions.     

Ganoderma australe from southern India

The genetic diversity of Ganoderma australe (Fr.) Pat. from southern India was investigated by using ITS1/2 rDNA. The phylogenetic analysis showed that six isolates clustered into two groups viz. biological species I and II. The four strains of BS I (YER03, MYC5, MYC2 and KE) clustered with G. australe TAI-01 and the two other strains of BS II (KMK3 and K39) were grouped with G. australe TAI-05 from Taiwan. The two strains namely TAI-01 and TAI-05 were described as G. australe intersterile Group 1 and 2 from Taiwan, respectively. The higher level nucleotide divergence among BS I and BS II and the high bootstrapping support clearly represent the presence of two biological species of G. australe in southern India which are genetically isolated.