In-vitro and In-vivo management of Meloidogyne incognita (Kofoid and White) Chitwood and Rhizoctonia bataticola (Taub.) Butler in cotton using organic’s

Root-knot nematodes Meloidogyne incognita (Kofoid and White) Chitwood and Rhizoctonia bataticola (Taub.) Butler, fungus, are very dangerous root damaging pathogens. Present study was planned to establish a chemical control of these root deteriorating pathogens under lab conditions as well as in field. Maximum death rate of nematode juveniles and minimum numbers of nematode eggs hatched were recorded in plates treated with Cadusafos (Rugby® 100G) @12 g/100 ml and Cartap® (4% G) @9g/100 ml. Chemical treatment of Rhizoctonia bataticola with Trifloxystrobin + Tebuconazole (Nativo®) @0.2 g/100 ml and Mancozeb + Matalaxyl (Axiom) @0.25 g/100 ml significantly controlled the mycelial growth in plates. The best treatments tested in laboratory were applied in field as protective and curative treatments. Results proved that chemical control of root-knot nematode and root rot fungi by tested chemicals at recommended time and dose is a significant management technique under field conditions.     

Gut microbiota composition is associated with environmental landscape in honey bees

There is growing recognition that the gut microbial community regulates a wide variety of important functions in its animal hosts, including host health. However, the complex interactions between gut microbes and environment are still unclear. Honey bees are ecologically and economically important pollinators that host a core gut microbial community that is thought to be constant across populations. Here, we examined whether the composition of the gut microbial community of honey bees is affected by the environmental landscape the bees are exposed to. We placed honey bee colonies reared under identical conditions in two main landscape types for 6 weeks: either oilseed rape farmland or agricultural farmland distant to fields of flowering oilseed rape. The gut bacterial communities of adult bees from the colonies were then characterized and compared based on amplicon sequencing of the 16S rRNA gene. While previous studies have delineated a characteristic core set of bacteria inhabiting the honey bee gut, our results suggest that the broad environment that bees are exposed to has some influence on the relative abundance of some members of that microbial community. This includes known dominant taxa thought to have functions in nutrition and health. Our results provide evidence for an influence of landscape exposure on honey bee microbial community and highlight the potential effect of exposure to different environmental parameters, such as forage type and neonicotinoid pesticides, on key honey bee gut bacteria. This work emphasizes the complexity of the relationship between the host, its gut bacteria, and the environment and identifies target microbial taxa for functional analyses.     

Enhancement of growth rate and β-galactosidase activity, and variation in organic acid profile of Bifidobacterium animalis subsp. lactis Bb 12

The behavior of Bifidobacterium animalis subsp. lactis Bb 12 under batch cultivation, after continuous culturing for up to 12 d, was monitored in skim milk-based media. Previous continuous culture for longer than 6 d affected the physiology of said microorganism. The minimum inhibitory concentrations of lactic and acetic acids increased from 18 to 26 g/l, whereas the molar ratio of acetic to lactic acid increased from 0.8 to 1.55, when the previous continuous culture increased its duration from 1 to 12 d. The specific lactose consumption rate decreased from 0.94 to 0.77 g_lactose/g_{cell dry mass}/h within the batch culture timeframe; this was concomitant with greater amounts of acetic and formic acids, and lower amounts of lactic acid produced. The β-galactosidase activity increased as continuous culturing time increased, and reached 446 units/ml by 12 d; however, the rate of enzyme synthesis decreased concomitantly. Succinic acid was produced during the exponential growth and stationary phases of the batch culture, but the former at exponential growth phase was higher as the continuous culturing time was longer. For comparison purposes, batch cultivation of samples taken from continuous cultures by 1 and 12 d was done using a semi-synthetic medium with glucose as carbon source; a pattern similar to that observed when using skim milk-based media was observed.     

CCL2/MCP-I genotype-phenotype relationship in latent tuberculosis infection

Among the known biomarkers, chemokines, secreted by activated macrophages and T cells, attract groups of immune cells to the site of infection and may determine the clinical outcome. Association studies of CCL-2/MCP-1 -2518 A/G functional SNP linked to high and low phenotypes with tuberculosis disease susceptibility have shown conflicting results in tuberculosis. Some of these differences could be due the variability of latent infection and recent exposure in the control groups. We have therefore carried out a detailed analysis of CCL-2 genotype SNP -2518 (A/G transition) with plasma CCL-2 levels and related these levels to tuberculin skin test positivity in asymptomatic community controls with no known exposure to tuberculosis and in recently exposed household contacts of pulmonary tuberculosis patients. TST positivity was linked to higher concentrations of plasma CCL2 (Mann Whitney U test; p = 0.004) and was more marked when the G allele was present in TST+ asymptomatic controls (A/G; p = 0.01). Recent exposure also had a significant effect on CCL-2 levels and was linked to the G allele (p = 0.007). Therefore association studies for susceptibility or protection from disease should take into consideration the PPD status as well as recent exposure of the controls group used for comparison. Our results also suggest a role for CCL-2 in maintaining the integrity of granuloma in asymptomatic individuals with latent infection in high TB burden settings. Therefore additional studies into the role of CCL-2 in disease reactivation and progression are warranted.     

Target cell contact suppresses neurite outgrowth from soma–soma paired Lymnaea neurons

Neurite extension from developing and/or regenerating neurons is terminated on contact with their specific synaptic partner cells. However, a direct relationship between the effects of target cell contact on neurite outgrowth suppression and synapse formation has not yet been demonstrated. To determine whether physical/synaptic contacts affect neurite extension from cultured cells, we utilized soma–soma synapses between the identified Lymnaea neurons. A presynaptic cell (right pedal dorsal 1, RPeD1) was paired either with its postsynaptic partner cells (visceral dorsal 4, VD4, and Visceral dorsal 2, VD2) or with a non‐target cell (visceral dorsal 1, VD1), and the interactions between their neurite outgrowth patterns and synapse formation were examined. Specifically, when cultured in brain conditioned medium (CM, contains growth‐promoting factors), RPeD1, VD4, and VD2 exhibited robust neurite outgrowth within 12–24 h of their isolation. Synapses, similar to those seen in vivo, developed between the neurites of these cells. RPeD1 did not, however, synapse with its non–target cell VD1, despite extensive neuritic overlap between the cells. When placed in a soma–soma configuration (somata juxtaposed against each other), appropriate synapses developed between the somata of RPeD1 and VD4 (inhibitory) and between RPeD1 and VD2 (excitatory). Interestingly, pairing RPeD1 with either of its synaptic partner (VD4 or VD2) resulted in a complete suppression of neurite outgrowth from both pre‐ and postsynaptic neurons, even though the cells were cultured in CM. A single cell in the same dish, however, extended elaborate neurites. Similarly, a postsynaptic cell (VD4) contact suppressed the rate of neurite extension from a previously sprouted RPeD1. This suppression of the presynaptic growth cone motility was also target cell contact specific. The neurite suppression from soma–soma paired cells was transient, and neuronal sprouting began after a delay of 48–72 h. In contrast, when paired with VD1, both RPeD1 and this non‐target cell exhibited robust neurite outgrowth. We demonstrate that this neurite suppression from soma–soma paired cells was target cell contact/synapse specific and Ca²⁺ dependent. Specifically, soma–soma pairing in CM containing either lower external Ca²⁺ concentration (50% of its control level) or Cd²⁺ resulted in robust neurite outgrowth from both cells; however, the incidence of synapse formation between the paired cells was significantly reduced. Taken together, our data show that contact (physical and/or synaptic) between synaptic partners strongly influence neurite outgrowth patterns of both pre‐ and postsynaptic neurons in a time‐dependent and cell‐specific manner. Moreover, our data also suggest that neurite outgrowth and synapse formation are differentially regulated by external Ca²⁺ concentration. © 2000 John Wiley & Sons, Inc. J Neurobiol 42: 357–369, 2000     

Shigella dysenteriae type 1-specific bacteriophage from environmental waters in Bangladesh

Shigella dysenteriae type 1 is the causative agent of the most severe form of bacillary dysentery, which occurs as epidemics in many developing countries. We isolated a bacteriophage from surface water samples from Bangladesh that specifically lyses strains of S. dysenteriae type 1. This phage, designated SF-9, belongs to the Podoviridae family and has a 41-kb double-stranded DNA genome. Further screening of water samples for the prevalence of the phage revealed 9 of 71 (12.6%) water samples which were positive for the phage. These water samples were also positive in PCR assays for one or more S. dysenteriae type 1-specific genes, including ipaBCD and stx1, and live S. dysenteriae type 1 was isolated from three phage-positive samples. The results of this study suggest that phage SF-9 may have epidemiological applications in tracing the presence of S. dysenteriae type 1 in environmental waters.     

Virtual high-throughput screening of natural compounds in-search of potential inhibitors for protection of telomeres 1 (POT1)

Communicated by Ramaswamy H. Sarma     

Impact of Protein Palmitoylation on the Virulence Potential of Cryptococcus neoformans

The localization and specialized function of Ras-like proteins are largely determined by posttranslational processing events. In a highly regulated process, palmitoyl groups may be added to C-terminal cysteine residues, targeting these proteins to specific membranes. In the human fungal pathogen Cryptococcus neoformans, Ras1 protein palmitoylation is essential for growth at high temperature but is dispensable for sexual differentiation. Ras1 palmitoylation is also required for localization of this protein on the plasma membrane. Together, these results support a model in which specific Ras functions are mediated from different subcellular locations. We therefore hypothesize that proteins that activate Ras1 or mediate Ras1 localization to the plasma membrane will be important for C. neoformans pathogenesis. To further characterize the Ras1 signaling cascade mediating high-temperature growth, we have identified a family of protein S-acyltransferases (PATs), enzymes that mediate palmitoylation, in the C. neoformans genome database. Deletion strains for each candidate gene were generated by homogenous recombination, and each mutant strain was assessed for Ras1-mediated phenotypes, including high-temperature growth, morphogenesis, and sexual development. We found that full Ras1 palmitoylation and function required one particular PAT, Pfa4, and deletion of the PFA4 gene in C. neoformans resulted in altered Ras1 localization to membranes, impaired growth at 37°C, and reduced virulence.