Clumping behavior as a strategy against drilling predation: Implications for the fossil record

Drilling gastropod predators are of particular interest to paleontologists, because predatory drill-holes in marine invertebrates serve as one of the rare sources of data for the study of ancient predator-prey interactions. Modern laboratory studies are an important part of predation research providing valuable ecological insight and constraining fossil evidence and interpretations. Previous studies have shown that mussels use clumping behavior against durophagous predation [Okamura, B., 1986. Group living and the effects of spatial position in aggregations of Mylitus edulis. Oecologia 69, 341-347.; Lin, J., 1991. Predator-prey interactions between blue crabs and ribbed mussels living in clumps. Estuar. Coast. Shelf Sci. 32, 61-69.], but its role against drilling predation had not been explored. In this study, we explore the effect of clumping on predator success (drill-hole frequency) and prey handling (drill-hole position) using the mussel, Mytilus trossulus, as prey and the gastropod, Nucella lamellosa, as drilling predator. We assigned mussels to two groups: in one, mussels were allowed to clump together with their byssal threads, and in the other, they were kept separate. We observed a significant decrease in the drilling frequency within the group containing clumped mussels, confirming that clumping acts as a successful anti-predatory strategy against drilling predators. The use of clumping as an effective strategy against multiple types of predators may relax the trade-offs associated with aggregated lifestyles [Bertness, M.D., Grosholz, E., 1985. Population dynamics of the ribbed mussel, Geukensia demissa: the costs and benefits of an aggregated distribution. Oecologia 67, 192-204.]. The increased benefit and unchanged metabolic cost of clumped living alters estimates of individual fitness with evolutionarily significant implications (e.g., eliminating the need to invoke group or species selection to explain the adaptive benefit of an aggregated lifestyle). In spite of potential differences in prey handling and grappling due to clumping, mean drill-hole placement and variation in drill-hole placement showed no significant differences between the two groups. These observations suggest that comparison of predation intensities across clumping and non-clumping taxa must consider the anti-predatory effect of this behavior.     

Chemotherapeutic potential of novel non-toxic nucleoside analogues on EAC ascitic tumour cells

Therapeutic efficacy of nucleoside analogues (NAs) like Gemcitabine, 5-fluorouracil in cancer treatment is already well established. Most of the known NAs are highly toxic to normal cells due to its non-specific action; thus searching for non-toxic NAs are still going on. For that purpose we have synthesised nine different NAs by alteration of their structural and functional groups. The aim of present study is to investigate the therapeutic potential of NAs against mice bearing breast adenocarcinoma cells at IC50 dose for 10 days treatment schedule. Results of the present study showed that, among the seven nucleoside analogues, NA-7 and NA-9 showed maximum therapeutic efficacy in controlling cancer cells by inhibiting cell proliferation and inducing apoptosis without any adverse effects to normal host cells. Additionally, NAs significantly decreased the tumour burden and enhanced survivability of host through generation of reactive oxygen species in tumour cells. These ultimately led to DNA damage, depolarisation of mitochondrial membrane potential and apoptosis in tumour cells. To find out the molecular mechanisms, we showed that administration of NA-7 and NA-9, down- regulating the expression of Bcl-2, cyclin D1, C-myc, P-21 and up-regulating the expression of P-53, Cyt-c, Bax, caspase-3 and caspase-9. The results suggest that NA-7 and NA-9 exhibits significant antitumor activity than 5-fluorouracil by modulating the cell cycle checkpoints and inducing apoptosis in Ehrlich ascites carcinoma (EAC)-bearing mice. Additionally, NA-7 and NA-9 did not show any clastogenic effect on bone marrow cells at sub-lethal dose. Thus, the present study clearly suggested therapeutic benefit of NAs by augmenting anticancer efficacy and diminishing toxicity to the host.     

Mucin-derived O-glycans supplemented to diet mitigate diverse microbiota perturbations

Microbiota-accessible carbohydrates (MACs) are powerful modulators of microbiota composition and function. These substrates are often derived from diet, such as complex polysaccharides from plants or human milk oligosaccharides (HMOs) during breastfeeding. Host-derived mucus glycans on gut-secreted mucin proteins serve as a continuous endogenous source of MACs for resident microbes; here we investigate the potential role of purified, orally administered mucus glycans in maintaining a healthy microbial community. In this study, we liberated and purified O-linked glycans from porcine gastric mucin and assessed their efficacy in shaping the recovery of a perturbed microbiota in a mouse model. We found that porcine mucin glycans (PMGs) and HMOs enrich for taxonomically similar resident microbes. We demonstrate that PMGs aid recovery of the microbiota after antibiotic treatment, suppress Clostridium difficile abundance, delay the onset of diet-induced obesity, and increase the relative abundance of resident Akkermansia muciniphila. In silico analysis revealed that genes associated with mucus utilization are abundant and diverse in prevalent gut commensals and rare in enteric pathogens, consistent with these glycan-degrading capabilities being selected for during host development and throughout the evolution of the host–microbe relationship. Importantly, we identify mucus glycans as a novel class of prebiotic compounds that can be used to mitigate perturbations to the microbiota and provide benefits to host physiology.Subject terms: Microbial ecology, Diseases     

Variation in colour-blindness in North-East India

Variation in colour-blindness in some of the populations of North-East India has been examined. The people of North-East India are found to be extremely variable with regard to this trait, the frequency ranging from 0 to 8.05%. An attempt has also been made to examine the present findings in light of the hypothesis put forward by Post (1962a,b) and others about selection relaxation.     

Kolavane and kaurane diterpenes from the stem bark of Xylopia aethiopica

The stem bark of Xylopia aethiopica has yielded four diterpenes, two of them novel. Three of the diterpenes were identified as (?)-kaur-16-en-19-oic acid and its 7-oxo and 7β-hydroxy derivatives. The fourth was the novel kolavane derivative 2-oxo-kolav-3,13-dien-15-oic acid, a type of compound not previously recorded in the Annonaceae.