FISH analysis of Zanthoxylum armatum based on oligonucleotides for 5S rDNA and (GAA)6.

Fluorescence in situ hybridization (FISH) using oligonucleotide probes for (GAA)6 (18 bp) and ribosomal DNA (rDNA) (5S rDNA, 41 bp) was applied to analyse Zanthoxylum armatum. (GAA)6 loci were detected on the pericentromeric regions of five chromosome pairs, and 5S rDNA loci were also detected on the pericentromeric regions of another two chromosome pairs. The densities and locations of (GAA)6 and 5S rDNA signals varied between individual chromosomes. High-intensity (GAA)6 signals were detected at the centromeres of two large and two smaller metacentric chromosomes. Relatively strong (GAA)6 signals were detected at the centromeres of two relatively small metacentric chromosomes, although strong 5S rDNA signals were detected at the centromeres of two additional smaller metacentric chromosomes. Weak (GAA)6 signals were detected at the centromeres of four large metacentric chromosomes, whereas weak 5S rDNA signals were detected at the centromeres of two smaller metacentric chromosomes. The remaining chromosomes exhibited no signals. Zanthoxylum armatum had 2n = ∼128. The lengths of the mitotic metaphase chromosomes ranged from 1.22 to 2.34 µm. Our results provide information that may be beneficial for future cytogenetic studies and could contribute to the physical assembly of the Zanthoxylum genome.

Genomic relationships among sixteen species of Avena based on (ACT)6 trinucleotide repeat FISH.

Knowledge of the locations of repeat elements could be very important in the assembly of genome sequences and their assignment to physical chromosomes. Genomic and species relationships among 16 species were investigated using fluorescence in situ hybridization (FISH) with the Am1 and (ACT)6 probes. The Am1 oligonucleotide probe was particularly enriched in the C genomes, whereas the (ACT)6 trinucleotide repeat probe showed a diverse distribution of hybridization patterns in the A, AB, C, AC, and ACD genomes but might not be present in the B and D genomes. The hybridization pattern of Avena sativa was very similar to that of A. insularis, indicating that this species most likely originated from A. insularis as a tetraploid ancestor. Although the two FISH probes failed to identify relationships of more species, this proof-of-concept approach opens the way to the use of FISH probes in assigning other signature elements from genomic sequence to physical chromosomes.

Breastfeeding after a cesarean section: A literature review.

BACKGROUND: Breast milk is recognized as the best source of nutrition for babies. The World Health Organization (WHO) recommends exclusive breastfeeding in the first six months after birth and continued breastfeeding for up to two years. According to the reported literature, breastfeeding and exclusive breastfeeding rates worldwide are relatively low, especially after a cesarean section (C-section). Therefore, this review aims to summarize existing data on C-section and breastfeeding performance worldwide to interpret their relationship further. METHODS: Research articles related to C-section and breastfeeding were retrieved from electronic databases, including CINAHL Complete, Health Source: Nursing/Academic Edition, Academic Search Complete, MEDLINE, PubMed, and Google Scholar. Only full-text English articles reported from 2015 to 2020 are summarized in this review. RESULTS: Among a total of 389 articles identified, 18 papers met our inclusion criteria, which reported that the C-section was associated with the initiation of breastfeeding and the duration of exclusive breastfeeding. Furthermore, these studies also discussed factors and experiences related to breastfeeding difficulties in mothers who have a C-section. Besides, several studies investigated effective initiatives that support breastfeeding in mothers who have a C-section. CONCLUSION: C-section is thought to be related to the initiation and duration of breastfeeding. In comparison with natural childbirth, C-section can delay the start of breastfeeding and shorten the duration of exclusive breastfeeding. Moreover, the planned C-section is considered the most critical factor affecting breastfeeding. Also, breastfeeding initiatives are highly recommended to support mothers who have a C-section. According to the literature, different regions and populations may have distinct experiences of breastfeeding. Therefore, future research is required to identify breastfeeding support for diverse populations with higher quality.

Molecular analysis of chloroquine resistance in Plasmodium falciparum in Yunnan Province, China.

Resistance of Plasmodium falciparum to chloroquine (CQ) is determined by the mutation at K76T of the P. falciparum chloroquine resistance transporter (pfcrt) gene and modified by other mutations in this gene and in the P. falciparum multidrug resistance 1 (pfmdr1) gene. To determine the extent of polymorphisms in these genes in field P. falciparum isolates from Yunnan province of China, we genotyped the pfcrt codon 76, pfmdr1 codons 86 and 1246. Our results showed that although CQ has been withdrawn from treating falciparum malaria for over two decades, 90.3% of the parasites still carried the pfcrt K76T mutation. In contrast, mutations at pfmdr1 codons 86 and 1246 were rare. Sequencing analysis of the pfcrt gene in 34 parasite field isolates revealed CVIET at positions 72-76 as the major type, consistent with the theory of Southeast Asian origin of CQ resistance in the parasite. In addition, two novel pfcrt haplotypes (75D/144Y/220A and 75E/144Y/220A) were identified. Real-time polymerase chain reaction was used to determine pfmdr1 gene amplification, which is associated with mefloquine resistance. Our result indicated that in agreement with that mefloquine has not been used in this area, most (>90%) of the parasites had one pfmdr1 copy. Genotyping at two hypervariable loci showed relatively low levels of genetic diversity of the parasite population. Meanwhile, 28.4% of cases were found to contain mixed clones, which favour genetic recombination. Furthermore, despite a unique history of antimalarial drugs in Yunnan, its geographical connections with three malarious countries facilitate gene flow among parasite populations and evolution of novel drug-resistant genotypes. Therefore, continuous surveillance of drug resistance in this area is necessary for timely adjustment of local drug policies and more effective malaria control.