Ecophysiological factors affecting growth,sporulation and survival of the biocontrol agent Penicillium oxalicum

The effect of temperature, pH, water potential and sources of nitrogen and carbon on the biocontrol agent Penicillium oxalicum were studied in vitro. The fungus is xerotolerant, mesophillic and has a wide pH tolerance. The parameters evaluated (germination, germ tube length, growth rate and sporulation) showed different sensitivities to the environmental factors. Peptone and free amino acids gave the highest growth rates and high levels of sporulation. Xylose, mannose and fructose gave the highest growth rates and mannose induced strong sporulation. The effect of nutrients (mannose + arginine) and water potential was also studied in vivo. The xerotolerant character of the fungus was confirmed. From this study we consider Penicillium oxalicum ecologically competent to perform effectively as a biocontrol agent in the soil environment. This revised version was published online in June 2006 with corrections to the Cover Date.     

Purification and characterization of a mucin-binding mycelial lectin from <Emphasis Type=Italic>Aspergillus nidulans</Emphasis> with potent mitogenic activity

Mucin-specific lectin from mycelium of Aspergillus nidulans was purified using anion exchange and gel filtration chromatographic techniques with an overall recovery of 32% and 21.97-fold purification. The purified lectin migrated as a single band in SDS–PAGE with an apparent molecular mass of 34 kDa. Carbohydrate analysis revealed that it is a glycoprotein with total sugar content of 2.54%. Optimal agglutination was observed when serially diluted lectin was incubated with human type O erythrocyte suspension at pH 7.0–8.0 and temperature 20–30°C. Lectin was found to be completely stable within pH 5.0–8.0 and temperature at or below 40°C. Demetallization by extensive dialysis against EDTA did not alter its haemagglutination activity. Lectin activity was reduced to half after 24 h incubation with urea and thiourea, with no such effect of guanidine HCl. The lectin showed potent mitogenic response towards mouse splenocytes, attaining a maximum at 200 μg/ml as compared to untreated control cells. Mitogenic lectins are invaluable tools to assess the functioning of immune cells. None of the microfungal lectin has yet been investigated for mitogenic activity. This is the first report on mitogenic activity of lectin from Aspergillus sp.     

Atomic Layer Deposition of CdS Quantum Dots for Solid‐State Quantum Dot Sensitized Solar Cells

Functioning quantum dot (QD) sensitized solar cells have been fabricated using the vacuum deposition technique atomic layer deposition (ALD). Utilizing the incubation period of CdS growth by ALD on TiO₂, we are able to grow QDs of adjustable size which act as sensitizers for solid‐state QD‐sensitized solar cells (ssQDSSC). The size of QDs, studied with transmission electron microscopy (TEM), varied with the number of ALD cycles from 1‐10 nm. Photovoltaic devices with the QDs were fabricated and characterized using a ssQDSSC device architecture with 2,2',7,7'‐tetrakis‐(N,N‐di‐p methoxyphenylamine) 9,9'‐spirobifluorene (spiro‐OMeTAD) as the solid‐state hole conductor. The ALD approach described here can be applied to fabrication of quantum‐confined structures for a variety of applications, including solar electricity and solar fuels. Because ALD provides the ability to deposit many materials in very high aspect ratio substrates, this work introduces a strategy by which material and optical properties of QD sensitizers may be adjusted not only by the size of the particles but also in the future by the composition.     

Enhancing estimation methods for integrating probability and nonprobability survey samples with machine-learning techniques. An application to a Survey on the impact of the COVID-19 pandemic in Spain

Web surveys have replaced Face-to-Face and computer assisted telephone interviewing (CATI) as the main mode of data collection in most countries. This trend was reinforced as a consequence of COVID-19 pandemic-related restrictions. However, this mode still faces significant limitations in obtaining probability-based samples of the general population. For this reason, most web surveys rely on nonprobability survey designs. Whereas probability-based designs continue to be the gold standard in survey sampling, nonprobability web surveys may still prove useful in some situations. For instance, when small subpopulations are the group under study and probability sampling is unlikely to meet sample size requirements, complementing a small probability sample with a larger nonprobability one may improve the efficiency of the estimates. Nonprobability samples may also be designed as a mean for compensating for known biases in probability-based web survey samples by purposely targeting respondent profiles that tend to be underrepresented in these surveys. This is the case in the Survey on the impact of the COVID-19 pandemic in Spain (ESPACOV) that motivates this paper. In this paper, we propose a methodology for combining probability and nonprobability web-based survey samples with the help of machine-learning techniques. We then assess the efficiency of the resulting estimates by comparing them with other strategies that have been used before. Our simulation study and the application of the proposed estimation method to the second wave of the ESPACOV Survey allow us to conclude that this is the best option for reducing the biases observed in our data.     

Photoacoustic Imaging of Breast Microcalcifications: A Preliminary Study with 8-Gauge Core-Biopsied Breast Specimens

Background

We presented the photoacoustic imaging (PAI) tool and to evaluate whether microcalcifications in breast tissue can be detected on photoacoustic (PA) images.

Methods

We collected 21 cores containing microcalcifications (n = 11, microcalcification group) and none (n = 10, control group) in stereotactic or ultrasound (US) guided 8-gauge vacuum-assisted biopsies. Photoacoustic (PA) images were acquired through ex vivo experiments by transmitting laser pulses with two different wavelengths (700 nm and 800 nm). The presence of microcalcifications in PA images were blindly assessed by two radiologists and compared with specimen mammography. A ratio of the signal amplitude occurring at 700 nm to that occurring at 800 nm was calculated for each PA focus and was called the PAI ratio.

Results

Based on the change of PA signal amplitude between 700 nm and 800 nm, 10 out of 11 specimens containing microcalcifications and 8 out of 10 specimens without calcifications were correctly identified on blind review; the sensitivity, specificity, accuracy, positive predictive and negative predictive values of our blind review were 90.91%, 80.0%, 85.71%, 83.33% and 88.89%. The PAI ratio in the microcalcification group was significantly higher than that in the control group (the median PAI ratio, 2.46 versus 1.11, respectively, P = .001). On subgroup analysis in the microcalcification group, neither malignant diagnosis nor the number or size of calcification-foci was proven to contribute to PAI ratios.

Conclusion

Breast microcalcifications generated distinguishable PA signals unlike breast tissue without calcifications. So, PAI, a non-ionizing and non-invasive hybrid imaging technique, can be an alternative in overcoming the limitations of conventional US imaging.     

Biofilm formation onto starch fibres by Bacillus subtilis governs its successful adaptation to chickpea milk

Beneficial biofilms may confer effective adaptation to food matrices that assist bacteria in enduring hostile environmental conditions. The matrices, for instance, dietary fibres of various food products, might serve as a natural scaffold for bacterial cells to adhere and grow as biofilms. Here, we report on a unique interaction of Bacillus subtilis cells with the resistant starch fibresof chickpea milk (CPM), herein CPM fibres, along with the production of a reddish-pink pigment. Genetic analysis identified the pigment as pulcherrimin, and also revealed the involvement of Spo0A/SinI pathway in modulating the observed phenotypes. Besides, through successful colonization of the CPM fibres, the wild-type cells of B. subtilis displayed enhanced survivability and resilience to environmental stress, such as heat and in vitro gastrointestinal treatments. In total, we infer that the biofilm formation on CPM fibres is an adaptation response of B. subtilis for strategic survival.     

Enzymatic synthesis of poly-l-lactide and poly-l-lactide-co-glycolide in an ionic liquid

The syntheses of poly-l-lactide (PLLA) and poly-l-lactide-co-glycolide (PLLGA) is reported in the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate [HMIM][PF₆] mediated by the enzyme lipase B from Candida antarctica (Novozyme 435). The highest PLLA yield (63%) was attained at 90 °C with a molecular weight (M _n ) of 37.8 × 10³ g/mol determined by size exclusion chromatography. This procedure produced relatively high crystalline polymers (up to 85% PLLA) as determined by DSC. In experiments at 90 °C product synthesis also occurred without biocatalyst, however, PLLA synthesis in [HMIM][PF₆] at 65 °C followed only the enzymatic mechanism as ring opening was not observed without the enzyme. In addition, the enzymatic synthesis of PLLGA is first reported here using Novozyme 435 biocatalyst with up to 19% of lactyl units in the resulting copolymer as determined by NMR. Materials were also characterized by TGA, MALDI-TOF–MS, X-ray diffraction, polarimetry and rheology.     

Functional evaluation of domain-domain interactions and human protein interaction networks

MOTIVATION: Large amounts of protein and domain interaction data are being produced by experimental high-throughput techniques and computational approaches. To gain insight into the value of the provided data, we used our new similarity measure based on the Gene Ontology (GO) to evaluate the molecular functions and biological processes of interacting proteins or domains. The applied measure particularly addresses the frequent annotation of proteins or domains with multiple GO terms. RESULTS: Using our similarity measure, we compare predicted domain-domain and human protein-protein interactions with experimentally derived interactions. The results show that our similarity measure is of significant benefit in quality assessment and confidence ranking of domain and protein networks. We also derive useful confidence score thresholds for dividing domain interaction predictions into subsets of low and high confidence. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.     

Decadal weakening of the wind-induced upwelling reduces the impact of nutrient pollution in the Bay of Málaga (western Mediterranean Sea)

The hypothesis that nitrate versus phosphate regulates the coastal primary production has been assessed at different time scales in the northwest Alboran Sea. Time series of temperature, salinity, nutrients and chlorophyll a obtained at three stations located off Málaga city (the greatest coastal urban core along the Alboran Sea shoreline) from 1992 to 2006 have been analysed. At the decadal scale, temperature increased linearly while salinity decreased. These changes were related to a shift in the wind regime suggesting that coastal upwelling became steadily weaker. In contrast to phosphate, nitrate was positively correlated with salinity at the seasonal scale and decreased linearly from 1992 to 2006. Seasonal and decadal changes in chlorophyll a were correlated with nitrate (and uncorrelated with phosphate). However, non-regular variability in chlorophyll a was correlated with phosphate. Consequently, the results demonstrate that nitrate controls the phytoplankton biomass at the inter-annual scale while both nitrate and phosphate do so at a shorter time scale. The Bay of Málaga receives elevated entries of domestic waste waters that release high loads of phosphate compared to nitrate. Our analysis indicates that the expected impact of this pollution on chlorophyll a at the inter-annual scale is reduced in comparison with the effects of atmospheric forcing.