Landscape structure influences natural pest suppression in a rice agroecosystem.

Agricultural landscapes are constantly changing as farmers adopt new production practices and respond to changing environmental conditions. Some of these changes alter landscape structure with impacts on natural pest control, pesticide use, and conservation of biodiversity. In rice agroecosystems the effect of landscape structure on natural enemies and pest suppression is often poorly understood. Here we investigate the effect of landscape composition and configuration on a key pest of rice, the brown planthopper (Nilaparvata lugens). Using N. lugens as sentinel prey coupled with predator exclusions, we investigated landscape effects on herbivore suppression and rice grain yield at multiple spatial scales in two regions of Bangladesh. Ladybird beetles and spiders were the most abundant natural enemies of N. lugens with landscape effects observed at all scales on ladybird beetles. Specifically, ladybird beetles were positively influenced by road edges, and fallow land, while spiders were strongly influenced only by rice phenology. Predator exclusion cages showed that N. lugens abundance significantly increased in caged plots, reducing rice gain yield. We also used an estimated biocontrol service index that showed a significant positive relationship with landscape diversity and a significant negative impact on pest density and yield loss. These results suggest that promoting fallow lands and fragmented patches between rice fields could lead to more sustainable insect pest management in rice agroecosystems, potentially reducing the practice of prophylactic insecticide use.

Role of White Blood Cell Count, Immature to Total Ratio and C-Reactive Protein in Early Detection of Clinically Suspected Neonatal Sepsis.

Despite recent advances in neonatal care, early detection of neonatal sepsis still remains challenging. Positive blood culture is the gold standard for definitive diagnosis of neonatal sepsis but is time consuming and demands a well equipped laboratory setting. Therefore, it becomes imperative to evaluate usefulness of white blood cell count, Immature to total (IT) ratio and C-reactive protein as potential markers in the early diagnosis of neonatal sepsis. The objective of the study was to evaluate role of white blood cell count, IT ratio and C-reactive protein in early detection of clinically suspected neonatal sepsis. This cross-sectional descriptive study was conducted from January 2017 to December 2018 at Special Care Newborn Unit (SCANU) of Rangpur Medical College Hospital, Rangpur, Bangladesh. After parental permission and ethical clearance, a total of 70 eligible neonates were included into the study. Estimation of total white blood cell count, IT ratio and C-reactive protein as well as blood culture were done for each case. Significance for Chi-Square test and Pearson's correlation coefficient test was predetermined as p<0.05. Of the total 70 neonates studied, 19(27.14%) were blood culture positive and most common organism was Escherichia coli (7/14, 37.0%). Among individual and combination tests, CRP was highly sensitive (100%) followed by WBC count (74.94%). Highly specific tests in diagnosing sepsis were combination test of IT ratio and CRP (88.23%) followed by combination test of WBC count and CRP (82.35%). Positive predictive value (PPV) was high for combination test of WBC count and CRP (90.90%) followed by combination test of IT ratio and CRP (90.47%). Negative predictive value (NPV) was high in CRP (100.0%) followed by WBC count (89.19%). IT ratio positively correlated with CRP (p=0.002) and there was significant association between raised CRP and WBC count (p=0.005) in neonatal sepsis. Diagnostic role of both individual and combination tests were significant in early detection of clinically suspected neonatal sepsis while awaiting results of blood culture. However, none of the combination tests were able to achieve 100.0% sensitivity.

Establishing next-generation pest control services in rice fields: eco-agriculture.

Pesticides are commonly used in food crop production systems to control crop pests and diseases and ensure maximum yield with high market value. However, the accumulation of these chemical inputs in crop fields increases risks to biodiversity and human health. In addition, people are increasingly seeking foods in which pesticide residues are low or absent and that have been produced in a sustainable fashion. More than half of the world's human population is dependent on rice as a staple food and chemical pesticides to control pests is the dominant paradigm in rice production. In contrast, the use of natural enemies to suppress crop pests has the potential to reduce chemical pesticide inputs in rice production systems. Currently, predators and parasitoids often do not persist in rice production landscapes due to the absence of shelter or nutritional sources. In this study, we modified the existing rice landscape through an eco-engineering technique that aims to increase natural biocontrol agents for crop protection. In this system, planting nectar-rich flowering plants on rice bunds provides food and shelter to enhance biocontrol agent activity and reduce pest numbers, while maintaining grain yield. The abundance of predators and parasitoids and parasitism rates increased significantly in the eco-engineering plots compared to the insecticide-treated and control plots. Moreover, a significantly lower number of principal insect pests and damage symptoms were found in treatments where flowering plants were grown on bunds than in plots where such plants were not grown. This study indicates that manipulating habitat for natural enemies in rice landscapes enhances pest suppression and maintains equal yields while reducing the need for insecticide use in crop fields.

Serum hyaluronic acid as a predictor of fibrosis in chronic hepatitis B and C virus infection.

Chronic hepatitis B and C virus infection can lead to cirrhosis and hepatocellular carcinoma. Several studies investigated the diagnostic and prognostic value of some biochemical markers to detect the hepatic fibrosis and found a correlation between serum markers and hepatic fibrosis. Among them serum hyaluronic acid (HA) has been identified as a potential marker of fibrosis or cirrhosis in different studies. A prospective study in 60 subjects was conducted to evaluate the association between serum HA and hepatic fibrosis. Thirty consecutive patients with chronic HBV or HCV infection undergoing liver biopsy were studied. Sera were obtained for HA using enzyme linked protein binding assay. Patients with hepatic fibrosis had higher serum HA concentration compared with healthy subjects (236.65 ± 227.07 vs. 23.32 ± 14.22 respectively, p<0.001). Correlation was found between high serum HA concentration and increasing degree of hepatic fibrosis (R-0.322 and p<0.041). This study had shown a good correlation between serum HA and different stages of hepatic fibrosis. So serum HA may be used as a useful marker of hepatic fibrosis.

Proteome analysis of a temperature-inducible recombinant Escherichia coli for poly-beta-hydroxybutyrate production.

A recombinant Escherichia coli strain harboring the lambdap(R)-p(L) promoter and heterologous poly-beta-hydroxybutyrate (PHB) biosynthesis genes was shown to accumulate PHB when the incubation temperature was changed from 34 degrees C to temperatures higher than 37 degrees C. In the present research, total gene expression patterns of the recombinant E. coli before and after induction were investigated by two-dimensional gel electrophoresis. Proteins encoded by serS, sucC, trpA, and alaS were found to be expressed before induction of phb genes at a culture temperature of 34 degrees C. On the other hand, proteins encoded by metG, rplI, and carA were found to be expressed after induction achieved by increasing the temperature to 40 degrees C. In the case of plasmid-free cells, all the selected genes have been shown to be expressed except metG, and ibpA and ibpB among the heat-shock proteins. The heat-shock proteins were found to be upregulated upon induction of phb genes, which may be due to the stress caused by the accumulation of PHB granules as well as by the temperature upshift. The changes in the expression of some of the metabolic pathway-related proteins before and after induction were interpreted in relation to the consumption of NADPH and acetyl-CoA for PHB synthesis.

Oligonucleotide probes based on 16S rRNA sequences for the identification of four Azospirillum species.

Partial sequences of the 16S rRNA molecules of nine strains belonging to four Azospirillum species were used to design species-specific oligonucleotide probes. Azospirillum strains sequences were analyzed and three homologous fragments containing 16 nucleotides were determined. These three probes were found to be characteristic of A. lipoferum (Al), A. irakense (Ai), and A. brasilense/amazonense species (Aba) and of few nontarget organisms. The specificity of these three probes was tested both against sequences in the GenBank data base and in numerous colony hybridization experiments. As a few non-target organisms hyridized with the different Azospirillum probes, the use of these probes in bulk soil hybridization is not permitted. However, their use together with specific isolation techniques is validated.