CHAPTER FOUR DISCUSSION AND CONCLUSIONS 4.1, General

CHAPTER FOUR
DISCUSSION AND CONCLUSIONS
4.1, General Discussion
The present study is a good example for protein polymorphism. Although
the samples were limited, results are very informative. Milk proteins from donkeys
are quite distinct from camel proteins. Results of this study are consistent with
other studies of mammalian milk proteins. Differences in PH, other physical and
chemical properties are clear in this study, same results are obtained by Miranda et
al. (2004).
The molecular mass of each class of caseins in Equids is in the range of
19.0-25.0 kDA (Miranda et a/,2004).In this study a crude estimate of molecular
weight is made due to lack of accurate protein markers. In mares milk the caseins
are present at maximum concentration, and therefore detectable quantities are
present making their characterization easy. On the other hand the separation
approaches described here (casein were precipitated by two methods: total protein
precipitation and casein isolectricly) followed by SDS-PAGE electrophoresis
reveled 4 classes, that is csl ,acasiens2 ,~ casein and k casein .However, Egito et
al. (2001, 2002) using HPLC under reducing conditions were not able to
differentiate as 1,acasiens2 and k casein.
The o-lacto albumin content are found in each sample of female milk in
conformity with previous studies. The ~ lacto globins varied and casein alleles
between the two mammals varied which may indicate that the casein allele
frequencies are highly affected by each other.
31
4.2. Conclusions and recommendations
Although donkeys are used in many parts of the country, very few studies
were carried on them. It can be concluded that milk proteins are useful genetic
tools to study genetic variation between different mammals. Not only that but they
can be used as genetic markers to differentiate mammalian breeds of both donkeys
and camels.
Doing this study some difficulties appeared of which getting the donkey milk was
the most difficult. Another difficulty was the preparation of acryl amide separating
gels.
Recommendations to be given from this study are:
1. More genetic studies for mammals of Sudan.
2. Future comparisons between milk donkeys and humans will be of great
importance.
3. Use of genetic markers, protein and DNA, are needed to differentiate
between donkey breeds.
32
REFERENCES
Beach A.M. and R.K. Kristiansen.
(1990). Milk protein polymorphism
in Danish
dairy cattle and the influence of genetic variants on milk yield. Journal of
Dairy Research 57: 53-62. Aaltonen, M.L and Antilal. (1987). Milk
renneting properties and genetic variants of proteins. Milch Wiss Enchatt,
42:490-492.
Aleandri, R.,Buttazzani,
G. ,Schneider, lC., Caroli, A. and R. Davoli .. (1990). The
effect of milk protein polymorphism
on milk components
and cheese
producing ability. Journal of Dairy Science 73:241-255.
Boirie, Y., Dangin, M., Gachon, P., Vasson, M.P., Maubois, lL. and Beaufrere, B.
(1997) . Slow and fast dietary proteins differently modulate postprandial
protein accretion. Proclamations
of National Academy of Sciences 94:
14930-14935.
Bovenhnis H.,Van arendank J.A.M.& Korvers (1992) Association
proteins polymorphism
between milk
and milk production traits. Journal of Dairy science
75: 2549-2559.
Bulliet, Richard (1975). THE CAMEL AND THE WHEEL. Morningside
Book
Series, Columbia University Press. p. 183.
chem.-43 :03-151
Chem.43:63-151
doi 10.1016/50065-3233(08)60554-9.PMID
1442324
Clin Immuno1.97(1996)1304-1307
Doi: 10.1016 / 50065-3233
Gall, H., Kalveram,C.M.,
(08) 60554-9. PMID 1442324.
Sick, H. and W. Sterry. (19977). Allergy to the heat-
labile .
33
•
Graml R.Buchberger H.&pirchner F (1985) pleiotrope Wirkungen von.blactoglobin and casein genotypean oul milchtett.und millchprotein
mengolendes Bayerischen fleckviehs und zuechtungsbio logi 102/33-45
Horne, D. S. (1998). Casein interactions casting light on the black boxes. The
structure in Diary product.lnt Dairy j. 8 (3): 171-177.
Horne, D.S. (1998). Casein interaction in diary production. lnt Dairy J 8 (3): 171177.
its Implication of Dairy sciuk 49(2) 317-22
Jakob E (1991) frequencies of casein phenotype and haplotypes in different breeds
in Switzerland and the effect ofK-casienC and Eon renneting properties of
milk
Lucay, lA. (2002). Formation and physical properties of milk proteins gel: J Dairy
Sci 88 (2) 281-94.
Ochirkhuyag, B, Chobert, J.M., Dalgalarrondo, M. and T. Haertle. (2002).
.
Characterization of mare casiens: Identification of as l-and as2 casien. Lait
80223-235
protiensAlpha-lactoabumin and b(eta -lactoglobin in mares milk,j,Allergy.
Walstia, P. (1979). The voluminosity of bovine casein micelles and some of its
implication. Dairy scin 46 (2) :317-322)
Walstra, P. (1979).The voluminosity of bovine casein micellels and some of some
of its implication of Dairy sciuk46(2)317-22 .
Rao et al(1998) hydrolyzes the peptide bond of K-casien.
Eistenmann(1995) competing aregument.
Bokanyi (1991 ).argud that domestication took place in elutton.
34
•
Mason and Maule, 1960.Somali donkey is described having Zebra marking on the
legs.
Haltenorth and Diller(1980).Donkeys rejected races.
3S
•
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__ w
_ Appendix I
Materials and amounts used to prepare two gels in SDS-PAGE:
Resolving gel
Staking gel
polyacrylamide
4ml
1.7ml
dH2
3.2ml
6.8ml
Tris-oH(I.5)m
2.5ml PH=8.8
1.25ml PH=6.8
lo%SDS
O.Olml
O.Olml
lo%ApS
O.Olml
O.Olml
Temed
O.Olml
O.Olml
Appendix 2
Running buffer
Tris-Base
3.02g
Glycine
14.4g
IO%SDS
l Oul
dH20
I liter
36
Appendix 3
Sample buffer( 4x)
Glycerol
SDS
4ml
.O.8g
Beta-mercapto ethanol
2.ml
Bromophenol blue20%
80ul
Sample
O.OOlg
dH20
8ml
Appendix 4
Staining buffer
Glacial acetic acid
56.7ml
Methanol
28.5ml
Coommassi blue
2g
dH20
62.5ml
37
.
•
Appendix 5
De-staining buffer
Glacial acetic acid
lOml
Methanol
50ml
dH20
lOOml
38