High-Throughput Nonlinear Optical Microscopy

High-resolution microscopy methods based on different nonlinear optical (NLO) contrast mechanisms are finding numerous applications in biology and medicine. While the basic implementations of these microscopy methods are relatively mature, an important direction of continuing technological innovation lies in improving the throughput of these systems. Throughput improvement is expected to be important for studying fast kinetic processes, for enabling clinical diagnosis and treatment, and for extending the field of image informatics. This review will provide an overview of the fundamental limitations on NLO microscopy throughput. We will further cover several important classes of high-throughput NLO microscope designs with discussions on their strengths and weaknesses and their key biomedical applications. Finally, this review will close with a perspective of potential future technological improvements in this field.     

The fate of the fusarium mycotoxin zearalenone in maize cell suspension cultures

The fusarium mycotoxin zearalenone was transformed in cell suspension cultures of Zea mays giving α- and β-zearalenol and the β-D-glu cos ides of zearalenone and α- and β-zearalenol. The structure of zearalenone-4-β-D-glucopyranoside was determined by liquid — chromatography-mass spectrometry and specific hydrolysis with β-glucosidase. α- and β-zearalenol and their glucosides were identified by co chromatography using tic and HPLC and glucosidase — treatment Up to 50% of the mycotoxin added was bound to a non extractable or “bound” residue fraction. After treating this residue by a sequential cell wall fractionation procedure, zearalenone was found to be bound mainly to starch, hemicellulose, and lignin fractions.     

Gene transfer is a major factor in bacterial evolution

Lateral gene transfer in four strains of Salmonella enterica has been assessed using genomic subtraction. Strain LT2 (subspecies I serovar Typhimurium) chromosomal DNA was used as target and subtracted by three subspecies I strains of serovars Typhimurium (S21), Muenchen (S71), Typhi (M229), and a subspecies V strain (M321). Data from probing random cosmids of LT2 DNA with preparations of the residual LT2 DNA after subtraction were used to estimate the amounts of LT2 DNA not able to hybridize to strains S21, S71, M229, and M321 to be in the range of 84-106, 191-355, 305-629, and 778-1,286 kb, respectively. Several lines of evidence indicate that most of this DNA is from genes not present in strain M321 and not from genes that have diverged in sequence. The amounts correlate with the divergence of the four strains as revealed by multilocus enzyme electrophoresis and sequence variation of housekeeping genes. Sequence of 39 of the fragments from the M321 subtracted residual LT2 DNA revealed only six inserts of known gene function with evidence of both gain and loss of genes during the development of S. enterica clones. Sixteen of the 39 segments have 45% or lower G+C content, below the species average, but over half are within the normal range for the species. We conclude that even within a species, clones may differ by up to 20% of chromosomal DNA, indicating a major role for lateral transfer, and that on the basis of G+C content, a significant proportion of the DNA is from distantly related species.      

Systematics of white-toothed shrews (Crocidura) (Mammalia: Insectivora: Soricidae) of Taiwan: Karyological and morphological Studies

We define the species boundaries of white-toothed shrews (genus Crocidura ) in Taiwan using karyological and morphological characteristics. Ninety-nine animals were obtained from all over Taiwan at capture rates usually less than 10%. Three species are recognized by distinct cytotypes: Crocidura attenuata tanakae 2n = 40, FN = 56; Crocidura suaveolens hosletti 2n = 40, FN = 50; Crocidura kurodai 2n = 40, FN = 54. A suite of six morphological characters diagnose the three species: shape of skull, position of incisive foramina, shape of fourth upper premolar, shape of pinna, tail vibrissae, and foot pads. A species key and notes on the life history of each species are provided. Finally, we discuss chromosomal evolution and biolgeography of Crocidura in East and South East Asia.     

Enhanced production of biomass and lipids by supplying CO2 in marine microalga Dunaliella sp.

Non-food-based biofuel feedstocks are in high demand worldwide. Among the various feedstocks, microalgae are the most promising feedstock for mitigating atmospheric CO₂ and producing biodiesel. In this study, various concentrations of CO₂, from 0.03 to 12%, were used to investigate their effect on the cell growth, biomass and lipid production and fatty acid composition of Dunaliella sp. in a closed photobioreactor. The results showed that the highest biomass and total lipids, 521 mg/L/d and 40 mg/L/d, respectively, were produced with 5% CO₂ aeration during the logarithmic growth phase. The oleic acid (18:1n9c) and elaidic acid (18:1n9t) contents were increased approximately two fold. The physiological responses of Dunaliella sp. at 10% CO₂ were similar to those at 5% CO₂. Therefore, the present results suggest that 5–10% is a suitable CO₂ concentration range for Dunaliella sp. growth to mitigate atmospheric CO₂ and increase biofuel production.     

Association of polymorphisms in the Chr18q11.2 locus with tuberculosis in Chinese population

A GWAS study has reported that two single nucleotide polymorphisms (SNPs) were associated with predisposition to tuberculosis (TB) in African populations. These two loci represented the long-waited GWAS hits for TB susceptibility. To determine whether these two SNPs are associated with TB in Chinese population, we attempted an replication in a cohort of over one thousand Chinese TB patients and 1,280 healthy controls using melting temperature shift allele-specific genotyping analysis. We found that only SNP rs4331426 was significantly associated with TB in Chinese population (p = 0.011). However, the effect was opposite. The G allele of the SNP in Chinese population is a protective allele (OR = 0.62, 95 % CI 0.44–0.87), while it was the risk allele for African population (OR = 1.19, 95 % CI 1.12–1.26). No significance was found for SNP rs2335704. The results provided an independent support for a role in susceptibility to TB for SNP rs4331426. However, it also indicated that direct predisposition element to TB and the association effects may vary across ethnic groups.     

High-Throughput Nonlinear Optical Microscopy

High-resolution microscopy methods based on different nonlinear optical (NLO) contrast mechanisms are finding numerous applications in biology and medicine. While the basic implementations of these microscopy methods are relatively mature, an important direction of continuing technological innovation lies in improving the throughput of these systems. Throughput improvement is expected to be important for studying fast kinetic processes, for enabling clinical diagnosis and treatment, and for extending the field of image informatics. This review will provide an overview of the fundamental limitations on NLO microscopy throughput. We will further cover several important classes of high-throughput NLO microscope designs with discussions on their strengths and weaknesses and their key biomedical applications. Finally, this review will close with a perspective of potential future technological improvements in this field.