May 8, 2012

XDH Gene Mutation is the Underlying Cause of Classical Xanthinuria: A Second Report

Xanthinuria is an autosomal recessive disorder that presents itself through excessive excretion of xanthine in urine. Type I xanthinuria results from a deficiency of xanthine dehydrogenase (xdh); the xdh gene is located at chromosome 2p22-23. Type II xanthinuria results from deficiency of both XDH and aldehyde oxidase. The primary purpose of the study was to understand the molecular basis of xanthinuria through an analysis xdh mutations; as such they are dealing with type I xanthinuria. Subtyping xanthinuria was attempted by homozygosity mapping. Mutation detection was accomplished by PCR-SSCP screening of the entire xdh gene; all 36 exons and exon-intron junctions of the patient’s gene. The gene sequence was then confirmed. The researchers determined that the xanthinuria in the patient is linked to the xdh gene mutation; as suggested by their data. As a result a new 1658insC mutation in exon 16 of the xdh gene was identified; through the analysis of the patient’s xdh gene. The researchers demonstrated the linkage of xanthinuria to the xdh locus by homozygosity mapping. Additionally, the newly identified 1658insC mutation predicted an inactivated xdh protein. They conclude by saying that their results “reinforce the notion that mutations in the xdh gene are the underlying cause of classical xanthinuria type I.”

References:

David Levartovsky, Ayala Lagziel, Oded Sperling, Uri Liberman, Michael Yaron, Tatsuo Hosoya, Kimiyoshi Ichida and Hava Peretz. Tel Aviv Sourasky Medical Center and Rabin Medical Center, Tel Aviv University, Tel Aviv, Israel; and The Jikey University School of Medicine, Tokyo, Japan. Published: 7 January 2000.

Additionally a Link to the Full Text is Provided Below:

http://www.nature.com/ki/journal/v57/n6/full/4491562a.html

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April 6, 2012

xdh PCR Results for 4-23 Through 4-33

Michael Page and Latara Janae performed the PCR amplification of extracted DNA 4-23 through 4-33 for the nuclear target region xdh. Following PCR amplification a gel was run to determine the extent of successful amplifications on the DNA. The first lane represents a genetic marker and the second lane is a water control. Results follow.

Figure 1: PCR Results for 4-23 Through 4-33 (xdh)

* Image taken by Dr. Jarrell

Gel Electrophoresis Results: All products had yield with roughly half of the samples having a high yield. Additionally our negative control shows no contamination. As seen in Figure 1, the genetic marker is very clear. Overall, this amplification worked very well.

++ (High Yield) + (Yield) – (No Yield)

Lane	DNA Code	Species or Marker	Success
1	Blank	DNA Marker	N/A
2	Negative Control	Water	N/A
3	4–23	DNA	+
4	4–24	DNA	+
5	4–25	DNA	++
6	4–26	DNA	++
7	4–27	DNA	++
8	4–28	DNA	+
9	4–29	DNA	++
10	4–30	DNA	++
11	4–31	DNA	++
12	4–32	DNA	++
13	4–33	DNA	++

Table 1: Gel Electrophoresis Results

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March 2, 2012

Trichoglottis bipunctata

Figure 1 : Extracted Plant Specimen (Tri. bipunctata)

Trichoglottis bipunctata (C. S. P. Parish & Rchb. f.) Tang & F. T. Wang, a member of the subtribe Aeridinae Pfitzer, is a medium sized monopodial epiphyte (uses another plant species for growth-support and grows upward from a single point). Tri. bipuctata has a scrambling stem from which linear leaves, clasped narrowly to the base of the stem, protrude. These leaves, as they elongate, narrow gradually to a blunt end. Tri. bipunctata can bloom any time of the year and has fragrant flowers. These flowers have pure yellow sepals and petals and are usually .8 centimeters in size.

Tri. bipunctata is found in Myanamar, Malaysia, and Thailand. It is typically found in elevations ranging from 50 to 300 meters above sea level. It is a hot growing plant with a minimum temperature range of around 15.5-28.3°C.