Effect of sciatectomy and induced ammonia stress on Mg2+_adenosine triphosphatase activity in frog tissues

Mg² + dependent —adenosine triphosphatase activity has been studied in the muscle, brain, kidney and liver tissues of frog,Rana hexadactyla (Lesson) after sciatectomy and induced chronic ammonia stress. The enzyme activity decreased in the tissues of the denervated frog. The activity of the enzyme increased in all the tissues of the normal and denervated frogs except in the denervated muscle when ammonium lactate was infused intraperitoneally.     

Aquatic oligochaeta from among the roots of eichhornia crassipes solms

The paper records the presence of sixteen species of aquatic oligochaetes, belonging to the Aeolosomatidae (1 species). Naididae (13 species) and Tubificidae (2 species), living in association with the floating roots of the water hyacinth, Eichhornia crassipes Solms., from a tank in Vizianagaram town in Andhra Pradesh, India. Of these, Aeolosoma hyalinum Bunke, 1967 and Dero obtusa D'Udekem, 1855 are new records for the Indian sub-continent.     

Two species of phreodrilidae (oligochaeta) new to Australia and Tasmania

Phreodrilus (Phreodrilus) branchiatus (Beddard, 1894) is reported for the first time in the eastern hemisphere from Tasmania. Phreodrilus (Phreodrilus) mauienensis Brinkhurst, 1971 is reported for the first time from Australia and Tasmania.     

Some aquatic oligochaetes of the Nilgiris,South India

Eight species of aquatic oligochaetes, belonging to the families Naididae and Tubificidae, are reported, of which six species are new to the Nigiris. Tubifex tubifex known from Coonoor is reported again from this area.     

Synthesis,characterization and in vitro biological evaluation of some novel 1,3,5-triazine–Schiff base conjugates as potential antimycobacterial agents

A series of some novel 1,3,5-triazine–Schiff base conjugates (1–32) have been synthesized and evaluated for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv using Alamar Blue assay and the activity expressed as the minimum inhibitory concentration (MIC) in μg/mL. Compounds 4 (4-Methoxy-6-methyl-N-(3,4,5-trimethoxybenzylidene)-1,3,5-triazin-2-amine), 11 (4-Methoxy-6-methyl-N-(2-hydroxy-3-bromo-5-chloro-benzylidene)-1,3,5-triazin-2-amine) and 24 (4-Methoxy-6-methyl-N-(1-(2,5-dihydroxyphenyl)ethylidene)-1,3,5-triazin-2-amine) exhibited a significant activity at 3.125, 6.25 and 6.25 μg/mL, respectively, when compared with the antitubercular drugs such as ethambutol (3.125 μg/mL), pyrazinamide (6.25 μg/mL) and streptomycin (6.25 μg/mL) and it could be a potential starting point to develop new lead compounds in the fight against Mycobacterium tuberculosis H37Rv.     

Enlarging a training set for genomic selection by imputation of un-genotyped animals in populations of varying genetic architecture

Background

The most common application of imputation is to infer genotypes of a high-density panel of markers on animals that are genotyped for a low-density panel. However, the increase in accuracy of genomic predictions resulting from an increase in the number of markers tends to reach a plateau beyond a certain density. Another application of imputation is to increase the size of the training set with un-genotyped animals. This strategy can be particularly successful when a set of closely related individuals are genotyped.

Methods

Imputation on completely un-genotyped dams was performed using known genotypes from the sire of each dam, one offspring and the offspring’s sire. Two methods were applied based on either allele or haplotype frequencies to infer genotypes at ambiguous loci. Results of these methods and of two available software packages were compared. Quality of imputation under different population structures was assessed. The impact of using imputed dams to enlarge training sets on the accuracy of genomic predictions was evaluated for different populations, heritabilities and sizes of training sets.

Results

Imputation accuracy ranged from 0.52 to 0.93 depending on the population structure and the method used. The method that used allele frequencies performed better than the method based on haplotype frequencies. Accuracy of imputation was higher for populations with higher levels of linkage disequilibrium and with larger proportions of markers with more extreme allele frequencies. Inclusion of imputed dams in the training set increased the accuracy of genomic predictions. Gains in accuracy ranged from close to zero to 37.14%, depending on the simulated scenario. Generally, the larger the accuracy already obtained with the genotyped training set, the lower the increase in accuracy achieved by adding imputed dams.

Conclusions

Whenever a reference population resembling the family configuration considered here is available, imputation can be used to achieve an extra increase in accuracy of genomic predictions by enlarging the training set with completely un-genotyped dams. This strategy was shown to be particularly useful for populations with lower levels of linkage disequilibrium, for genomic selection on traits with low heritability, and for species or breeds for which the size of the reference population is limited.     

Bacterial colonization of Hydra hatchlings follows a robust temporal pattern

Animals are colonized by complex bacterial communities. The processes controlling community membership and influencing the establishment of the microbial ecosystem during development are poorly understood. Here we aimed to explore the assembly of bacterial communities in Hydra with the broader goal of elucidating the general rules that determine the temporal progression of bacterial colonization of animal epithelia. We profiled the microbial communities in polyps at various time points after hatching in four replicates. The composition and temporal patterns of the bacterial communities were strikingly similar in all replicates. Distinct features included high diversity of community profiles in the first week, a remarkable but transient adult-like profile 2 weeks after hatching, followed by progressive emergence of a stable adult-like pattern characterized by low species diversity and the preponderance of the Betaproteobacterium Curvibacter. Intriguingly, this process displayed important parallels to the assembly of human fecal communities after birth. In addition, a mathematical modeling approach was used to uncover the organizational principles of this colonization process, suggesting that both, local environmental or host-derived factor(s) modulating the colonization rate, as well as frequency-dependent interactions of individual bacterial community members are important aspects in the emergence of a stable bacterial community at the end of development.