Annual Research & Review in Biology

Cassava brown streak disease (CBSD) is caused by two viruses; Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV) that are genetically distinct. The disease can cause losses of up to 100 million US Dollars and it has a big impact on cassava yields. There is relatively little genetic information of CBSVs, their distribution and genetic diversities in Kenya. This study was therefore to establish the extent of distribution and diversity of CBSV and UCBSV strains in the Kenya. A survey was conducted in Coast, Western and Nyanza which are the major cassava-growing areas of Kenya. The mean disease incidence in Coast was 47.8%, Western 33.0% and Nyanza 55.9%. The average mean severity score cassava brown streak virus was 2.0 for Coast, 2.4 for Western and 2.6 for Nyanza.  A reverse transcriptase polymerase chain reaction (RT-PCR) was used to screen 131 samples and of these 24 positive and negatives samples representing each region were selected for next generation sequencing. RT-PCR detected single infections of CBSV, UCBSV and co infections 19.8%, 22.1% and 34.4% of the positive reactions respectively countrywide. Alignment from assembled coat protein sequences revealed two clusters representing the two strains. The study also revealed a mixed infection in the samples from the surveyed fields. The widespread distribution of CBSV and UCBSV in Coast, Western and Nyanza farmer’s field in Kenya has implications in the cassava production in those regions.

Jatropha curcas is a Euphorbiaceae whose seed lipids attract biofuel industry attention. However, the effects of environmental stressors inducing resistance mechanisms and affecting the seed yield of the plant are very little investigated. In this study, we evaluated the effect of water stress and sunlight luminosity on the antioxidant enzymes activities of Jatropha curcas. Seeds of three Jatropha curcas ecotypes coming from Burkina Faso were sown in reduced sunlight luminosity condition in the greenhouse. A 20 day water stress and/or 20 day direct sunlight stress was applied to 33 weeks old plants. Control plants grew in the greenhouse under a reduced sunlight quantity and received one liter water daily. The activities of leaf antioxidant enzymes, catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) were measured using a spectrophotometer. The results showed that plants of Sahelian zone containing the greatest proline content had the highest enzymatic activity thereby indicating a better adaptation of the sahelian ecotype of J. curcas to water deficit and direct sunlight luminosity. The effect of water stress on enzymatic activities was more pronounced than the effect of direct sunlight luminosity. Our results suggest that the mechanisms modulating the enzymatic activity of young plants of J. curcas controlled by water deficit, such as inhibition of photosynthesis and photorespiration reinforcing, were earlier set up.

Aims and Study Design: Epidermal growth factor receptor (EGFR) regulates a number of cellular processes, including cell motility, proliferation, differentiation and survival. EGFR mediated signal transduction via mitogen activated protein kinase (MAPK) modulates expression and activity of matrix metalloproteinases (MMPs). Elevated expression and activity of MMP-2 strongly correlates with increased tumour invasiveness. As numerous studies indicate that all-trans retinoic acid (ATRA) has considerable anti-tumorigenic potential, the effect of ATRA on EGFR mediated regulation of MMP-2 via MAPK was studied in this paper using the highly metastatic murine melanoma cell line B16F10 as a model.

Methodology: B16F10 cells were cultured in the presence of ATRA (20 μM) for 6, 15 and 24 hrs. EGFR expression and phosphorylation and p38MAPK expression were assayed by Western blot. MMP-2 activity was assayed by gelatin zymography of culture supernatants. MMP-2 and TIMP-2 mRNA expression were assayed by RT-PCR. DNA fragmentation was used to assay the efficacy of ATRA in causing apoptosis.

Results: Treatment of B16F10 murine melanoma cells with ATRA (20 µM) for 24 hrs led to an appreciable downregulation of EGFR phosphorylation and expression of EGFR and p38MAPK. Treatment of B16F10 cells with ATRA also inhibited MMP-2 activity and downregulated transcription of MMP-2 while transcription of TIMP-2 was upregulated. Treatment with ATRA did not show appreciable fragmentation of DNA.

Conclusion: Downregulation of EGFR expression and phosphorylation and EGFR mediated signal transduction through p38 MAPK could lead to downregulation of MMP-2 transcription. Downregulation of MMP-2 transcription and upregulation of transcription of the MMP inhibitor TIMP-2 could result in loss of MMP-2 activity. Loss of MMP-2 activity would render cells less metastatic. Our findings indicate that treatment with ATRA can inhibit EGFR mediated regulation of MMP-2 activity in B16F10 murine melanoma cells. Such inhibition could have therapeutic potential in clinical management of tumours.

Research data on taxonomy of the members of the family Palmariaceae (Palmariales, Rhodophyta) from the Russian Pacific coasts are presented.  Special attention is paid to taxonomic status of two genera of palmarialean algae inhabiting the area: Halosaccion and Devaleraea. The genus Halosaccion is presented in the Russian Pacific area by 3 species: H. glandiforme (=H. hydrophorum), H. minjaii, H. yendoi (= D. yendoi). The first one H. glandiforme is proposed herein as a type species of the genus Halosaccion, while H. hydrophorum is treated as a later taxonomic synonym of H. glandiforme. The generic position of H. yendoiis hitherto controversial. It was described originally as H. yendoi, then transferred to Devaleraea, but later on reinstated within Halosaccion on the basis of genetic data in spite of anatomy typical of the genus Devaleraea. Taxonomic assignment of Halosaccion firmum raised doubts as well. It is anatomically close to Devaleraea and probably should be transferred to this genus. This supposition, based on anatomical parameters, is supported by preliminary genetic data, so a new combination Devaleraea firma (Postels et Ruprecht) Selivanova is presented herein with the proviso that genetic studies will be continued to confirm our results. At present the genus Devaleraea in the studied area is shown to include for sure only one species D. compressa in addition to D. firma. Generic attribution of D. microspora (=H. microsporum) remains questionable until molecular genetic data are available.

Aims: To assess molecular diversity and to determine species-specific loci of Indonesian durio, based on Inter-Simple Sequence Repeat (ISSR) markers.

Study Design: Genomic DNA isolation from fresh durio leaves and then DNA amplification. Electrophoresis PCR product and bands scoring. Calculating the diversity genetic parameter and identification specific loci.

Place and Duration of Study: The research was done in Plant Biology Laboratory, Biology Departments, Bogor Agricultural University, start from April 2014 until January 2016.

Methodology: Ten ISSR primers were used to reveal the genetic diversity of 58 varieties of three species (D. zibethinus, D. kutejensis, and D. tanjungpurensis) sampled from Mekarsari and Cipaku Garden, West Java, and from Sekadau Regency, West Kalimantan, Indonesia. Genetic diversity parameters were estimated based on binary data of PCR bands appearance which calculation using GenAlEx. Construction phenogram using Mega software and validating of loci specific with Chi-Square method invoked SAS® software.

Results: The diversity genetic parameter showed that the mean number of observed alleles, the mean number of effective alleles, Shannon’s Information Index, the genetic diversity, and the percentage of polymorphic loci were 1.25, 1.34, 0.30, 0.20, and 58.3%, respectively. UPGMA based cluster analysis and principal coordinate analysis classified them into three groups according to the species. We found 13 loci from 7 ISSR primers linked to species-specific loci.

Conclusion: The genetic diversity of durio can be assessed using the ISSR markers, which can also be used for species identification of Indonesian durio.

Polycystic ovary syndrome (PCOS) is a common complex condition in women associated with reproductive, metabolic and psychological features. PCOS is the most common endocrine disorder in the reproductive age of women. These patients are prone to develop sleep-disordered breathing (SDB), metabolic disorders and cardiovascular disease (CVD). Studies over the past decade show that lifestyle can help in disease progression. Various lifestyle factors play an important role as prevalence of PCOS is rising in adolescents, particularly with the endorsement of modernized lifestyle. Sleep is an important part of health and wellness. Recent studies have showed that, a reduced sleep duration and quality sleep can have an effect on hypothalamus-pituitary-adrenal (HPA) axis activity. The HPA axis is under regulatory control of circadian oscillators and reduced sleep duration and quality sleep can have an effect on HPA axis activity. In this study we review the quality of sleep and stress in women with PCOS.

The increased abiotic stresses were severe threat to world food security paving to hunger death. To combat this situation crops with high tolerance should be developed. Crop improvement mainly depends on the improvement of traits that increase yield levels with high tolerance to abiotic stresses. It is known that the expression of the trait is purely under control of gene whose expression is temporal, spatial and stimulus specific. The molecular dissection of each tolerance mechanism at transcriptional, post transcriptional, translational and signaling pathway levels helps in easy understanding of the specific traits imparting tolerance. The identification of functional markers associated with abiotic stress tolerance and manipulation of key functional or regulatory genes through molecular approaches like genetic engineering assist crop improvement with in short time. Hence, in this review we would summarize stimulus perception, signal transduction pathway (MAP kinase and ROS pathways), formation of regulatory protein, gene expression, synthesis of osmolytes (proline, glycine betaine, fructans) and other event that takes place under drought stress, heat stress and cold stress.